研究者データベース

川﨑 了(カワサキ サトル)
工学研究院 環境循環システム部門 地圏循環工学分野
教授

基本情報

所属

  • 工学研究院 環境循環システム部門 地圏循環工学分野

職名

  • 教授

学位

  • 博士(工学)(鳥取大学)
  • 工学修士(鳥取大学)

ホームページURL

科研費研究者番号

  • 00304022

J-Global ID

研究キーワード

  • 微生物   シリカ   リン酸カルシウム   炭酸カルシウム   軟岩   ビーチロック   地盤改良   応用地質   試験法   新材料   物性評価   力学特性   非破壊試験   バイオグラウト   保存材料   

研究分野

  • エネルギー / 地球資源工学、エネルギー学
  • 社会基盤(土木・建築・防災) / 地盤工学
  • 人文・社会 / 博物館学
  • 人文・社会 / 文化財科学

職歴

  • 2014年04月 - 現在 北海道大学(大学院工学研究院環境循環システム部門) 教授
  • 2010年04月 - 2014年03月 北海道大学(大学院工学研究院環境循環システム部門) 准教授
  • 2007年04月 - 2010年03月 北海道大学(大学院工学研究科環境フィールド工学専攻) 准教授
  • 2006年12月 - 2007年03月 岐阜大学(工学部社会基盤工学科) 非常勤講師
  • 2005年04月 - 2007年03月 北海道大学(大学院工学研究科環境フィールド工学専攻) 助教授
  • 2002年05月 - 2005年03月 北海道大学(大学院工学研究科環境資源工学専攻) 助教授
  • 2000年02月 - 2002年04月 大阪大学(大学院工学研究科地球総合工学専攻) 学内講師
  • 2001年06月 - 2001年09月 岐阜大学(工学部土木工学科) 非常勤講師
  • 1998年04月 - 2000年01月 大阪大学(大学院工学研究科地球総合工学専攻) 助手
  • 1998年03月 - 1998年03月 大阪大学(工学部土木工学科) 助手
  • 1997年01月 - 1998年02月 財団法人電力中央研究所(我孫子研究所地盤耐震部) 主任研究員
  • 1995年08月 - 1996年12月 財団法人電力中央研究所(我孫子研究所耐震部土質グループ) 主査研究員
  • 1990年08月 - 1995年07月 財団法人電力中央研究所(我孫子研究所立地部土質研究室) 担当研究員
  • 1988年04月 - 1990年07月 財団法人電力中央研究所(我孫子研究所立地部土質研究室) 研究員

学歴

  • 1997年04月 - 1999年03月   鳥取大学   大学院工学研究科   社会開発工学専攻 博士後期課程(社会人コース)
  • 1986年04月 - 1988年03月   鳥取大学   大学院工学研究科   海洋土木工学専攻 修士課程
  • 1982年04月 - 1986年03月   鳥取大学   工学部   土木工学科

所属学協会

  • 日本生物工学会   日本地球惑星科学連合   日本工学教育協会   日本応用地質学会   土木学会   資源・素材学会   岩の力学連合会   ISSMGE   ISRM   地盤工学会   

研究活動情報

論文

  • Maksym Avramenko, Kazunori Nakashima, Satoru Kawasaki
    Materials 15 19 6878  2022年10月03日 [査読有り][通常論文]
  • Influence of humic acid on microbial induced carbonate precipitation for organic soil improvement
    Meiqi Chen, Sivakumar Gowthaman, Kazunori Nakashima, Satoru Kawasaki
    Environmental Science and Pollution Research 1 - 11 2022年09月 [査読有り][通常論文]
  • Control of adhesion property of mussel foot protein by fusing soluble protein
    Anju Pilakka Veedu, Kazunori Nakashima, Takahiro Sato, Satoru Kawasaki
    The 19th Asian Pacific Confederation of Chemical Engineering (APCChE) Congress 2022年08月 [査読有り][通常論文]
  • Metal biosorption process under strongly acidic conditions: A part of sustainable metal recycling system
    Chikara Takano, Koichi Murayama, Kazunori Nakashima, Satoru Kawasaki, Hideki Aoyagi
    International Union of Microbiological Societies 2022年07月 [査読有り][通常論文]
  • Zhen Yan, Sivakumar Gowthaman, Kazunori Nakashima, Satoru Kawasaki
    Scientific Reports 12 8821  2022年05月25日 [査読有り][通常論文]
  • Functional modification of mussel adhesive protein for the control of adhesion and aggregation property
    Anju Pilakka Veedu, Kazunori Nakashima, Takahiro Sato, Satoru Kawasaki
    European Federation of Biotechnology (EFB) Spring 2022 2022年05月 [査読有り][通常論文]
  • Effects of reaction conditions on EICP-treated desert aeolian sand
    Linyu Wu, Linchang Miao, Satoru Kawasaki, Hengxing Wang
    KSCE Journal of Civil Engineering 2022年03月24日 [査読有り][通常論文]
  • Durability improvement of biocemented sand by fiber-reinforced MICP for coastal erosion protection
    Md Al Imran, Kazunori Nakashima, Niki Evelpidou, Satoru Kawasaki
    Materials 15 7 2389  2022年03月24日 [査読有り][通常論文]
  • Solubilization and aggregation control of silica-polymerizing enzyme fused with a removable soluble protein
    Hidetoshi Oguri, Kazunori Nakashima, Kasun Godigamuwa, Junnosuke Okamoto, Yudai Takeda, Fumiyoshi Okazaki, Masafumi Sakono, Satoru Kawasaki
    Journal of Bioscience and Bioengineering 133 3 222 - 228 2022年03月 [査読有り][通常論文]
  • Developing a new soil improvement technology using calcium phosphate bio-cement derived from bone waste
    M. M. S. Ahamed, M. Y. M. Husny, Sivakumar Gowthaman, Satoru Kawasaki
    The 3rd Edition of Advancements in Geotechnical Engineering from Research to Practice (AGERP): International Workshop on Biogeotechnics 2022年02月 [査読有り][通常論文]
  • Coir fiber reinforced EICP-based bio-cementation for the production of low-cost sand bricks
    R. Dinoth, P. Purushalini, S. Gowthaman, Satoru Kawasaki
    The 3rd Edition of Advancements in Geotechnical Engineering from Research to Practice (AGERP): International Workshop on Biogeotechnics 2022年02月 [査読有り][通常論文]
  • Bio-cementation of demolition waste and recycled aggregates for sustainable pavement construction
    W. M. Nabris, J. P. Roshan, S. Gowthaman, Satoru Kawasaki
    The 3rd Edition of Advancements in Geotechnical Engineering from Research to Practice (AGERP): International Workshop on Biogeotechnics 2022年02月 [査読有り][通常論文]
  • Sivakumar Gowthaman, Arash Mohsenzadeh, Kazunori Nakashima, Satoru Kawasaki
    Materials Today: Proceedings 61 2 243 - 249 2022年02月 [査読有り][通常論文]
  • Ning‐Jun Jiang, Yi‐Jie Wang, Jian Chu, Satoru Kawasaki, Chao‐Sheng Tang, Liang Cheng, Yan‐Jun Du, Bettadapura S. Shashank, Devendra N. Singh, Xiao‐Le Han, Yu‐Ze Wang
    Soil Use and Management 38 1 68 - 93 2022年01月28日 [査読有り][通常論文]
  • Beachrock formation mechanism using multiproxy experimental data from natural and artificial beachrocks: Insights for a potential soft engineering method
    Giannis Saitis, Anna Karkani, Eleni Koutsopoulou, Konstantinos Tsanakas, Satoru Kawasaki, Niki Evelpidou
    Journal of Marine Science and Engineering 10 1 87  2022年01月10日 [査読有り][通常論文]
  • Geochemical characterization of the coastal alluvial aquifer in Wates, Yogyakarta, Indonesia
    Phyu Phyu Thin, Heru Hendrayana, Wahyu Wilopo, Satoru Kawasaki
    Proceedings of the 13th AUN/SEED-Net Regional Conference on Geological and Geo-Resource Engineering (RC GeoE 2021) 2021年12月 [査読有り][通常論文]
  • Influence of cementation level on the mechanical behavior of bio-cemented slope soil treated by surface injection
    S. Gowthaman, M. Chen, H. Nakamura, K. Nakashima, S. Kawasaki
    Proceedings of the Third International Conference on Geotechnical Engineering ICGE-Colombo-2020 401 - 406 2021年12月 [査読有り][通常論文]
  • Polymer modified microbial induced carbonate precipitation: Novel approach to densify the loose sand
    T. H. K. Nawarathna, K. Nakashima, S. Kawasaki
    Proceedings of the Third International Conference on Geotechnical Engineering ICGE-Colombo-2020 332 - 336 2021年12月 [査読有り][通常論文]
  • A soil improvement method based on plant-derived urease-induced carbonate precipitation
    R. A. N. Dilrukshi, K. Nakashima, S. Kawasaki
    Proceedings of the Third International Conference on Geotechnical Engineering ICGE-Colombo-2020 361 - 366 2021年12月 [査読有り][通常論文]
  • Aggregation of magnetite particles by mussel adhesive protein triggered by protease
    Anju Pilakka Veedu, Kazunori Nakashima, Hiroki Miyagawa, Satoru Kawasaki
    The 26th Symposium of Young Asian Biological Engineers’ Community (YABEC2021) 2021年11月 [査読有り][通常論文]
  • Plant enzyme induced carbonate precipitation for sand cementation
    Linyu Wu, Linchang Miao, Satoru Kawasaki
    Proceedings of the Eleventh International Conference on Geotechnique, Construction Materials and Environment (GEOMATE 2021) 63 - 68 2021年11月 [査読有り][通常論文]
  • High water content peat soil improved by MICP technique with fiber reinforcement
    Meiqi Chen, Sivakumar Gowthaman, Kazunori Nakashima, Shin Komatsu, Satoru Kawasaki
    Proceedings of the Eleventh International Conference on Geotechnique, Construction Materials and Environment (GEOMATE 2021) 16 - 21 2021年11月 [査読有り][通常論文]
  • Evaluating the effects of polymers on microbially induced carbonate precipitation
    Zhen Yan, Sivakumar Gowthaman, Kazunori Nakashima, Satoru Kawasaki
    Proceedings of the Eleventh International Conference on Geotechnique, Construction Materials and Environment (GEOMATE 2021) 10 - 15 2021年11月 [査読有り][通常論文]
  • Used Paper Fibers for Sustainably Enhancing the MICP Stabilization of Sand
    Meiqi Chen, Sivakumar Gowthaman, Kazunori Nakashima, Shin Komatsu, Satoru Kawasaki
    Proceedings of the 6th GeoChina International Conference on Civil & Transportation Infrastructures: From Engineering to Smart & Green Life Cycle Solutions (GeoChina 2021) 52 - 64 2021年09月19日 [査読有り][通常論文]
  • Meiqi Chen, Sivakumar Gowthaman, Kazunori Nakashima, Shin Komatsu, Satoru Kawasaki
    Materials 14 18 5164  2021年09月08日 [査読有り][通常論文]
     
    Recently, green materials and technologies have received considerable attention in geotechnical engineering. One of such techniques is microbially-induced carbonate precipitation (MICP). In the MICP process, CaCO3 is achieved bio-chemically within the soil, thus enhancing the strength and stiffness. The purpose of this study is to introduce the wastepaper fiber (WPF) onto the MICP (i) to study the mechanical properties of MICP-treated sand with varying WPF content (0-8%) and (ii) to assess the freeze-thaw (FT) durability of the treated samples. Findings revealed that the ductility of the treated samples increases with the increase in WPF addition, while the highest UCS is found with a small fiber addition. The results of CaCO3 content suggest that the WPF addition enhances the immobilization of the bacteria cells, thus yielding the precipitation content. However, shear wave velocity analysis indicates that a higher addition of WPF results in rapid deterioration of the samples when subjected to freeze-thaw cycles. Microscale analysis illuminates that fiber clusters replace the solid bonding at particle contacts, leading to reduced resistance to freeze-thaw damage. Overall, the study demonstrates that as a waste material, WPF could be sustainably reused in the bio-cementation.
  • Calcium phosphate biocement using bone meal and acid urease: An eco-friendly approach for soil improvement
    Sivakumar Gowthaman, Moeka Yamamoto, Kazunori Nakashima, Volodymyr Ivanov, Satoru Kawasaki
    Journal of Cleaner Production 319 128782  2021年08月22日 [査読有り][通常論文]
  • Thiloththama H. K. Nawarathna, Kazunori Nakashima, Tetsuya Kawabe, Wilson Mwandira, Kiyofumi Kurumisawa, Satoru Kawasaki
    ACS Sustainable Chemistry & Engineering 9 34 11493 - 11502 2021年08月12日 [査読有り][通常論文]
     
    Biomineralization is a process of mineral formation in living organisms. Compared with nonbiogenic minerals, biominerals can be defined as organic-inorganic hybrid materials that have excellent physical and optical properties. In the current study, an artificial protein mimicking the outer shell of crayfish, composed of CaCO3, chitin, and proteins, was developed to facilitate organic-inorganic hybrid material formation by precipitation of calcium carbonate on the chitin matrix. The fusion protein (CaBP-ChBD) was constructed by introducing a short-sequence calcite-binding peptide (CaBP) into the chitin-binding domain (ChBD). Calcium carbonate precipitation experiments by enzymatic urea hydrolysis revealed that a significant increase in the CaCO3 formation was achieved by adding CaBP-ChBD. Also, CaCO3 was efficiently deposited on chitin particles decorated with CaBP-ChBD. Most interestingly, CaBP-ChBD would improve the performance in sand solidification more efficiently and sustainably in the process of biocementation technique. The developed recombinant protein could be used for the sustainable production of organic-inorganic green materials for engineering applications.
  • CO2-induced carbonate minerals as soil stabilizing agents for dust suppression
    Hamed A. Keykha, Hadi Mohamadzadeh Romiani, Ehsan Zebardast, Afshin Asadi, Satoru Kawasaki
    Aeolian Research 52, 100731 2021年08月03日 [査読有り][通常論文]
  • Sivakumar Gowthaman, Meiqi Chen, Kazunori Nakashima, Satoru Kawasaki
    Frontiers in Environmental Science 9: 690376 1 - 13 2021年07月12日 [査読有り][通常論文]
     
    Peat is one of the most challenging and problematic soils in the fields of geotechnical and environmental engineering. The most critical problems related to peat soils are extremely low strength and high compressibility, resulting in poor inhabitancy and infrastructural developments in their vicinity. Thus far, peat soils were stabilized using Portland cement; however, the production of Portland cement causes significant emission of greenhouse gases, which is not environmentally desirable. Microbial-induced carbonate precipitation (MICP) is an innovative technique for improving the mechanical properties of soil through potentially environmentally friendly processes. This article presents a laboratory study carried out with the aim of investigating the viability and effect of scallop shell powder (SSP) on enhancing the mechanical properties of the MICP-treated amorphous peat. The hypothesis was that the distribution of SSP (as-derived calcite particles) would (i) provide more nucleation sites to precipitates and (ii) increase the connectivity of MICP bridges to facilitate mineral skeleton to amorphous peat, accompanied by an increase in its compressive strength. Specimens were treated at varying combinations of SSP and MICP reagents, and the improvement was comprehensively assessed through a series of unconfined compression tests and supported by microscale and chemical analyses such as scanning electron microscopy, energy-dispersive X-ray analysis, and X-ray diffraction analysis. The outcomes showed that incorporating SSP in MICP treatment would be a promising approach to treat amorphous peat soils. The proposed approach could improve the unconfined compressive strength by over 200% after a 7-day curing period, while the conventional MICP could not exhibit any significant improvements.
  • Sivakumar Gowthaman, Kazunori Nakashima, Satoru Kawasaki
    Journal of Soils and Sediments 21 2831 - 2844 2021年06月11日 [査読有り][通常論文]
  • Pahala Ge Nishadi Nayanthara, Anjula Buddhika Nayomi Dassanayake, Kazunori Nakashima, Satoru Kawasaki
    Journal of Sedimentary Environments 6 93 - 106 2021年06月 [査読有り][通常論文]
     
    AbstractBeachrocks are sedimentary structures where gravelly or sandy beaches have been transformed into rock outcrops formed through precipitation of connective cements amid their interstices. They are well-noted coastal features along the coastal belt of Sri Lanka due to the prevalent tropical climate. This study was aimed at gathering data on surface nature and cementation characteristics of beachrock occurrences along a part of Sri Lankan shoreline through field observations and a series of analyses including X-ray diffraction, X-ray fluorescence, scanning electron microscopy (SEM) techniques and petrographic thin-section analysis. The combined research findings from different techniques are also employed as a preliminary step to determine the formation mechanism of the studied beachrocks. The seaward-inclined low-angle beds running parallel to present shoreline are composed mostly of sandstone with occasional conglomerate. Almost all the beachrocks are made of quartz grains amalgamated by cement. One remarkable feature of Sri Lankan beachrocks is the presence of heavy minerals generally in thin lamina form. The cementing agents are predominantly composed of metastable carbonate phases, high magnesium calcite (HMC) and aragonite (Ar) with varying microfabrics and textures. From SEM examinations and thin-section images, main morphologies identified are acicular Ar, scalenohedral magnesium calcites along with bridge cements and micritic coatings which are typical of a marine-phreatic precipitation with the exception of occasional meniscus cements. Further, the presence of evidences of living organisms may be an indication of influence from the biological aspects which can be confirmed by more detailed analyses.
  • Fabrication of silica on chitin in ambient conditions using silicatein fused with a chitin-binding domain
    Kasun Godigamuwa, Kazunori Nakashima, Sota Tsujitani, Satoru Kawasaki
    Bioprocess and Biosystems Engineering 44 9 1883 - 1890 2021年05月11日 [査読有り][通常論文]
  • Md Al Imran, Kazunori Nakashima, Satoru Kawasaki
    Crystals 11 5 516  2021年05月06日 [査読有り][通常論文]
     
    Recently, soil improvement using EICP (Enzyme-Induced Carbonate Precipitation) methods in the geotechnical and geo-environmental field has become a prominent interest worldwide. The objective of this study was to develop an improved extraction technique of crude urease from watermelon seeds in both dry and germinated conditions. Subsequently, this study also analyzed the improvement methodology of crystal polymorphs and soil bonding incorporation of various Mg2+/Ca2+ ratios. The optimization of enzyme-mediated carbonate precipitation was also investigated by Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) analysis. Results confirmed that the precipitated crystals are mainly calcite, vaterite and aragonite primarily (depending on the Mg2+/Ca2+ ratios). Therefore, to improve the bonding capacity in between the sand particles a novel improvement methodology was investigated by adding various Mg2+/Ca2+ ratios. The mechanical properties of the treated soil (Mikawa Sand, D-50 = 0.870 mm) specimens were tested by unconfined compressive strength (UCS) and this confirmed the effectiveness of adding various Mg2+/Ca2+ ratios. The results of the UCS tests showed that, the lower molar ratios of Mg2+/Ca2+ can significantly improve the UCS of the specimen (up to 50%) which could be considered a significant outcome for different bio-geotechnical applications.
  • Fabrication of chitosan gel-silica hybrid materials using fusion silicatein
    Kasun Godigamuwa, Kazunori Nakashima, Satoru Kawasaki
    Virtual conference organized by the European Federation of Biotechnology (EFB2021) 2021年05月 [査読有り][通常論文]
  • Insights in beachrock formation mechanism using multiproxy experimental data: Case study of Diolkos, Corinth, Greece
    Giannis Saitis, Konstantinos Tsanakas, Anna Karkani, Satoru Kawasaki, Niki Evelpidou
    European Geosciences Union General Assembly 2021, vEGU21 2021年04月27日 [査読有り][通常論文]
  • S. Gowthaman, K. Nakashima, S. Kawasaki
    International Journal of Environmental Science and Technology Online first article 1 - 14 2021年04月15日 [査読有り][通常論文]
  • Experimental study on strengthening near-surface of slopes using bio-grouting technique
    Sivakumar Gowthaman, Kazunori Nakashima, Hiromi Nakamura, Satoru Kawasaki
    Proceedings of the 1st International Symposium on Construction Resources for Environmentally Sustainable Technologies (CREST 2020) 2021年03月10日 [査読有り][通常論文]
  • Hadi Mohamadzadeh Romiani, Hamed Abdeh Keykha, Milad Talebi, Afshin Asadi, Satoru Kawasaki
    Proceedings of the Institution of Civil Engineers - Ground Improvement Ahead of Print 1 - 26 2021年02月22日 [査読有り][通常論文]
  • Md Al Imran, Kazunori Nakashima, Niki Evelpidou, Satoru Kawasaki
    International Journal of GEOMATE 20 78 148 - 153 2021年02月 [査読有り][通常論文]
     
    In recent years, the formation of artificial beachrock and bio-cementation method has gained considerable attention as a sustainable alternative tool in the area of geotechnical and geo-environmental engineering field for soil improvement and construction materials. In general, earlier methods of soil improvement were mostly concentrated on microbes (Bacteria, Fungi, etc.) as a source of urease enzyme widely known as MICP method (Microbial Induced Carbonate Precipitation). To address some of the key limitations of MICP method this study focused on using crude enzyme (low cost, eco-friendly). Crude enzyme was extracted from watermelon seeds (Citrullus lanatus) considered as "food waste material" and the carbonate formation process known as EICP "Enzyme Induced Carbonate Precipitation." Crushed and blended watermelon seeds (both dry and germinated) used as a source of urease enzyme. Subsequently, their urease activity was also investigated with various environmental parameters (Temperature, pH, etc.) and investigated the carbonate precipitation trend using calcium chloride (CaCl2) and urea [(CO(NH2)(2)]. The form of carbonate (calcite, aragonite, vaterite, etc.) was also confirmed by XRD and SEM-EDX analysis. Finally, syringe (d = 2.3 cm, h= 7.1 cm) sand solidification test was conducted using commercially available "Mikawa sand" (mean diameter, D-50 = 870 mm) and successfully achieved unconfined compressive strength (UCS) of about 1.2 MPa at neutral pH (similar to 7) and temperature condition (30 degrees C) considering various curing days and conditions. This study could be useful as an eco-friendly and sustainable method for numerous bio-geotechnical applications (for instance, ground improvement, liquefaction mitigation, artificial beach rock formations, coastal erosion protection, etc.) and the extracted crude urease from watermelon seeds could play as an alternative to replace commercially available urease for carbonate precipitation.
  • Meiqi Chen, Sivakumar Gowthaman, Kazunori Nakashima, Satoru Kawasaki
    International Journal of GEOMATE 20 78 121 - 127 2021年02月 [査読有り][通常論文]
     
    Peat soil is an accumulation of partially decayed vegetation, formed under the condition of nearly permanent water saturation, which makes the high moisture and compressibility as two main features of peat. In recent years, the lack of construction lands diverts researchers' attention to make use of marginal grounds, like peatland, after some improvements. The past decade has witnessed a growing interest in microbial induced carbonate precipitation (MICP) due to its reliability, broad application, and potential contribution to sustainable and green development. This study has two primary aims: (i) investigating the feasibility and effectiveness of MICP in peat soil combined with bamboo fiber reinforcement, and (ii) ascertaining the mechanism of bamboo fiber incorporated MICP. Bamboo fiber possesses some unparalleled advantages owing to its fast growth and ability to survive in diverse climates. This study differs from previous researches in the use of native bacteria isolated from the peat soil, while most of them were conducted using exogenous bacteria, which might pose a threat regarding adaption and microbial pollution. Different concentrations of cementation resources (1-3 mol/L) and proportion of fibers (0-50%) were studied, and each case was well designed. Treated samples were subjected to the fall cone test to estimate the undrained shear strength at certain time intervals. The results revealed that samples with higher fiber content gained higher strength than others did, whereas high initial cementation resources in soil could reduce strength. Microscale observations were also performed on treated samples to clarify the mechanism of MICP incorporated with fiber.
  • A. Mohsenzadeh, E. Aflaki, S. Gowthaman, K. Nakashima, S. Kawasaki, T. Ebadi
    International Journal of Environmental Science and Technology Online first article 2021年01月27日 [査読有り][通常論文]
  • Lutfian R. Daryono, Kazunori Nakashima, Satoru Kawasaki, Anastasia D. Titisari, Didit H. Barianto, Imam Suyanto, Arief Rahmadi
    Bulletin of Engineering Geology and the Environment 80 3 2825 - 2844 2021年01月10日 [査読有り][通常論文]
     
    A great deal of progress has been made in recent years to investigate the chemical characteristics of beachrocks. Beachrocks found in Krakal-Sadranan Beach (Yogyakarta, Indonesia) are spread locally, parallel to the coastline with a breadth of about 10-30 m(2). In this research, unmanned aerial vehicle (UAV) drone mapping, geological analysis, direct current resistivity survey, and surface seismic surveys were conducted to detect the underground structure of the beachrocks and to emphasize the coastal mapping based on targeted beachrocks. The correlation was developed between the sections and the data on the study site. Toward survey validation, laboratory tests were conducted on the beachrock samples collected from the study site to identify its properties. The evolution of the coastal zone based on beachrocks study is highly affected by relative sea-level changes that were described in the 3D model of beachrocks. The coastal changes are significantly impact the natural and cultural resources, and the understanding of coastal evolution is important for the preservation, development, and management of the coastal zone. This paper focused on the cementation processes and mechanism of beachrocks as a natural wave barrier in a tropical area, which is also appropriate for advanced marine ecosystems study including shorelines microbiotas.
  • Wilson Mwandira, Kazunori Nakashima, Satoru Kawasaki, Allison Arabelo, Kawawa Banda, Imasiku Nyambe, Meki Chirwa, Mayumi Ito, Tsutomu Sato, Toshifumi Igarashi, Hokuto Nakata, Shouta Nakayama, Mayumi Ishizuka
    Scientific Reports 10 1 21189 - 21189 2020年12月 [査読有り][通常論文]
     
    AbstractThe present study investigated biosorption of Pb (II) and Zn (II) using a heavy metal tolerant bacterium Oceanobacillus profundus KBZ 3-2 isolated from a contaminated site. The effects of process parameters such as effect on bacterial growth, pH and initial lead ion concentration were studied. The results showed that the maximum removal percentage for Pb (II) was 97% at an initial concentration of 50 mg/L whereas maximum removal percentage for Zn (II) was at 54% at an initial concentration of 2 mg/L obtained at pH 6 and 30 °C. The isolated bacteria were found to sequester both Pb (II) and Zn (II) in the extracellular polymeric substance (EPS). The EPS facilitates ion exchange and metal chelation-complexation by virtue of the existence of ionizable functional groups such as carboxyl, sulfate, and phosphate present in the protein and polysaccharides. Therefore, the use of indigenous bacteria in the remediation of contaminated water is an eco-friendly way of solving anthropogenic contamination.
  • Development of artificial beachrock using watermelon seeds as a source of urease
    Md. Al Imran, Kazunori Nakashima, Niki Evelpidou, Satoru Kawasaki
    Proceedings of the Tenth International Conference of Geotechnique, Construction Materials and Environment (GEOMATE 2020) 356 - 361 2020年11月 [査読有り][通常論文]
  • Evaluation on the performance of MICP treated slope soil under acid rain environment
    Sivakumar Gowthaman, Arash Mohsenzadeh, Kazunori Nakashima, Hiromi Nakamura, Satoru Kawasaki
    Proceedings of the Tenth International Conference of Geotechnique, Construction Materials and Environment (GEOMATE 2020) 82 - 87 2020年11月 [査読有り][通常論文]
  • Mechanical strength of peat soil treated by fiber incorporated microbial cementation
    Meiqi Chen, Sivakumar Gowthaman, Kazunori Nakashima, Satoru Kawasaki
    Proceedings of the Tenth International Conference of Geotechnique, Construction Materials and Environment (GEOMATE 2020) 41 - 46 2020年11月 [査読有り][通常論文]
  • Enzyme Induced Biocementation Using Watermelon Seed as a Source of Urease
    Md Al Imran, Kazunori Nakashima, Satoru Kawasaki
    Proceedings of the First International Conference (Online) on Microbial Biotechnology in Construction Materials and Geotechnical Engineering (MBCMG2020) 2020年11月 [査読有り][通常論文]
  • Mechanical Strength of Organic Soil Treated by Fiber Incorporated Microbial Cementation
    Sivakumar Gowthaman, Pahala Ge Nishadi Nayanthara, Kazunori Nakashima, Satoru Kawasaki, Atsuko Sato
    Proceedings of the First International Conference (Online) on Microbial Biotechnology in Construction Materials and Geotechnical Engineering (MBCMG2020) 2020年11月 [査読有り][通常論文]
  • Heru Hendrayana, Phyu Phyu Thin, Wahyu Wilopo, Satoru Kawasaki
    E3S Web of Conferences, The 1st Geosciences and Environmental Sciences Symposium (ICST 2020) 200 02005 - 02005 2020年10月23日 [査読有り][通常論文]
     
    The studied coastal aquifer has been encountered a complex hydrochemical evolution. Interesting aspect is the occurrence of groundwater facies with different water chemistries in close proximity to each other. Water salinity is reported from local parts away from shore. This research was conducted for assessment of aquifer weathering and its control on groundwater chemistry. An investigation of major ions in 27 water samples was performed with geostatistics, graphical method, mineral saturation index and mass balance transport to identify the groundwater evolution. Geochemical analysis of sediments was made of 8 samples, to estimate the weathering degree using chemical index of alteration and chemical index of weathering. Silicate dissolution was promoted by low weathering, which was reflected in low ions dominated by calcium and bicarbonate in fresh water. It leaded to fine sands. Silts were dominant under moderate weathering. Sodium and calcium were higher than fresh water. Bicarbonate was still highest concentration. Main water was the mixed type which was indicated by moderate ions. Clays were formed by high weathering. Water salinity with highest dissolved solids was caused by halite dissolution and calcium adsorption on clays. Overall, groundwater chemistry in the study area is locally characterized by prevailing lithology in grouping patterns.
  • The Influence of the Addition of Plant-Based Natural Fibers (Jute) on Biocemented Sand Using MICP Method
    Md Al Imran, Sivakumar Gowthaman, Kazunori Nakashima, Satoru Kawasaki
    Materials 13 18 4198  2020年09月 [査読有り][通常論文]
  • Jing He, Satoru Kawasaki, Varenyam Achal
    Sustainability 12 17 6971 - 6971 2020年08月27日 [査読有り][通常論文]
     
    Concrete, as the world’s most implemented construction material, is increasingly being used because of the rapid development of industrialization and urbanization. Limited resources and progressive depravation of the environment are forcing scientific efforts to seek alternative and effective materials from large amounts of natural resources as additives in the partial replacement of cement. Cement is a main constituent of concrete. To solve and minimize environmental issues, research works attempting to employ the wide availability of agricultural wastes, such as sugar cane bagasse, rice husk, sugar cane straw, and palm oil fuel, among others, into cement, and to finally bring sustainable and environmentally friendly properties to concrete are being examined. Agro-waste materials are crushed into fine and coarse aggregates or are burnt into ash, and are then mixed with cement, which is known as agro-cement. The replacement of aggregates, either partially or fully, is also deemed as a sustainable material in construction. This paper mainly reviews the current research on agro-cement that has been researched and applied for the enhancement of the strength and durability of concrete. It further summarizes the relevant knowledge and techniques, while providing optimal parameters for applying agricultural wastes in concrete.
  • Sivakumar Gowthaman, Kazunori Nakashima, Satoru Kawasaki
    Soils and Foundations 60 4 840 - 855 2020年08月 [査読有り][通常論文]
  • Kasun Godigamuwa, Kazunori Nakashima, Junnosuke Okamoto, Satoru Kawasaki
    Biomacromolecules 2020年06月16日 [査読有り][通常論文]
  • Influence of Wet-Dry and Freeze-Thaw Cycles on the Physical and Mechanical Properties of MICP Treated Slope Soil
    S. Gowthaman, K. Nakashima, H. Nakamura, S. Kawasaki
    Proceedings of the 54th U.S. Rock Mechanics/Geomechanics Symposium ARMA-2020-1119 2020年06月 [査読有り][通常論文]
  • Innovative Approach for Addressing Coastal Erosion Protection Using Microbial Induced Carbonate Precipitation
    Md Al Imran, Kazunori Nakashima, Niki Evelpidou, Satoru Kawasaki
    European Geosciences Union General Assembly 2020 2020年05月 [査読有り][通常論文]
  • A Feasibility Investigation for Developing Artificial Beachrocks: A Potential Measure for Coastal Protection in Southeast Yogyakarta Coast, Indonesia
    Lutfian Rusdi Daryono, Kazunori Nakashima, Satoru Kawasaki, Koichi Suzuki, Anastasia Dewi Titisari, Didit Hadi Barianto, Imam Suyanto, Arief Rahmadi
    European Geosciences Union General Assembly 2020 2020年05月 [査読有り][通常論文]
  • Cellulose-metallothionein biosorbent for removal of Pb(II) and Zn(II) from polluted water
    Wilson Mwandira, Kazunori Nakashima, Yuki Togo, Tsutomu Sato, Satoru Kawasaki
    Chemosphere 246 125733  2020年05月 [査読有り][通常論文]
  • Investigation of natural beachrock and physical-mechanical comparison with artificial beachrock induced by MICP as a protective measure against beach erosion at Yogyakarta, Indonesia
    Lutfian R. Daryono, Kazunori Nakashima, Satoru Kawasaki, Koichi Suzuki, Imam Suyanto, Arief Rahmadi
    Geosciences 10 4 143  2020年04月 [査読有り][通常論文]
  • A novel metal adsorbent composed of hexa-histidine tag and carbohydrate-binding module on cellulose
    Yuki Togo, Kazunori Nakashima, Wilson Mwandira, Satoru Kawasaki
    Analytical Sciences 36 4 459 - 464 2020年04月 [査読有り][通常論文]
  • Microbial Leaching of Iron from Hematite: Direct or Indirect Elution
    Apichaya Aneksampant, Kazunori Nakashima, Satoru Kawasaki
    Materials Transactions 61 2 396 - 401 2020年02月 [査読有り][通常論文]
  • Sediment characteristics of beachrock: A baseline investigation based on microbial induced carbonate precipitation at Krakal-Sadranan Beach, Yogyakarta, Indonesia
    Lutfian Rusdi Daryono, Kazunori Nakashima, Satoru Kawasaki, Anastasia Dewi Titisari, Didit Hadi Barianto
    Applied Sciences 10 2 520  2020年01月 [査読有り][通常論文]
  • Evolution of relative sea level in Okinawa (Japan) during Holocene
    Niki Evelpidou, Satoru Kawasaki, Anna Karkani, Giannis Saitis, Giorgio Spada, Georgios Economou
    Geografia Fisica e Dinamica Quaternaria 42 1 3 - 16 2019年12月 [査読有り][通常論文]
  • Laboratory conditions for maximal calcium carbonate precipitation induced by Sporosarcina pasteurii and Sporosarcina aquimarina bacteria
    Hamed A. Keykha, Afshin Asadi, Bujang B. K. Huat, Satoru Kawasaki
    Environmental Geotechnics 6 8 562 - 566 2019年12月 [査読有り][通常論文]
  • Feasibility study for slope soil stabilization by microbial induced carbonate precipitation (MICP) using indigenous bacteria isolated from cold subarctic region
    Sivakumar Gowthaman, Takashi Iki, Kazunori Nakashima, Koji Ebina, Satoru Kawasaki
    SN Applied Sciences 1 11 1480  2019年11月 [査読有り][通常論文]
  • Biocementation of Sri Lankan beach sand using locally isolated bacteria: A baseline study on the effect of segregated culture media
    Pahala Ge Nishadi Nayanthara, Anjula Buddhika Nayomi Dassanayake, Kazunori Nakashima, Satoru Kawasaki
    International Journal of GEOMATE 17 63 55 - 62 2019年11月 [査読有り][通常論文]
  • A novel sustainable approach for coastal erosion protection through biocementation
    Md Al Imran, Shuya Kimura, Kazunori Nakashima, Niki Evelpidou, Satoru Kawasaki
    Applied Sciences 9 20 4462  2019年10月 [査読有り][通常論文]
  • A Comparative Study of Beachrock Mechanism Formation Focusing on Natural and Artificial Beachrocks: Case of Diolkos, Corinth, Greece and Sumuide, Okinawa, Japan
    Giannis Saitis, Eleni Koutsopoulou, Niki Evelpidou, Satoru Kawasaki
    The International Association of Geomorphologists (IAG) Regional Conference on Geomorphology (RCG2019) P.2.05 2019年09月 [査読有り][通常論文]
  • Engineered Escherichia coli cell capable of specific binding to metal surface
    K. Nakashima, Y. Iwata, S. Kawasaki
    ACS Fall 2019 National Meeting & Exposition, San Diego, United States 2019年08月 [査読有り][通常論文]
  • Microbially induced carbonate precipitation assisted by poly-L-lysine: ecofriendly approach inspired by nature
    T.H.K. Nawarathna, K. Nakashima, S. Kawasaki
    ACS Fall 2019 National Meeting & Exposition, San Diego, United States 2019年08月 [査読有り][通常論文]
  • Beachrock identification using geology and geophysical approaches in Indonesia
    Daryono L. R, Nakashima K, Kawasaki S, Titisari A. D, Barianto D. H, Suyanto I, Rahmadi A
    Proceedings of International Symposium on Earth Resources Management and Environment, ISERME 2019 51 - 59 2019年08月 [査読有り][通常論文]
  • Microbial Induced Carbonate Precipitation Using a Native Inland Bacterium for Beach Sand Stabilization in Nearshore Areas
    Pahala Ge Nishadi Nayanthara, Anjula Buddhika Nayomi Dassanayake, Kazunori Nakashima, Satoru Kawasaki
    Applied Sciences 9 15 3201  2019年08月 [査読有り][通常論文]
  • Wilson Mwandira, Kazunori Nakashima, Satoru Kawasaki, Mayumi Ito, Tsutomu Sato, Toshifumi Igarashi, Meki Chirwa, Kawawa Banda, Imasiku Nyambe, Shouta Nakayama, Hokuto Nakata, Mayumi Ishizuka
    Chemosphere 228 17 - 25 2019年08月 [査読有り][通常論文]
     
    Environmental impacts resulting from historic lead and zinc mining in Kabwe, Zambia affect human health due to the dust generated from the mine waste that contains lead, a known hazardous pollutant. We employed microbially induced calcium carbonate precipitation (MICP), an alternative capping method, to prevent dust generation and reduce the mobility of contaminants. Pb-resistant Oceanobacillus profundus KBZ 1-3 and O. profundus KBZ 2-5 isolated from Kabwe were used to biocement the sand that would act as a cover to prevent dust and water infiltration. Sand biocemented by KBZ 1-3 and KBZ 2-5 had maximum unconfined compressive strength values of 3.2 MPa and 5.5 MPa, respectively. Additionally, biocemented sand exhibited reduced water permeability values of 9.6 × 10-8 m/s and 8.9 × 10-8 m/s for O. profundus KBZ 1-3 and KBZ 2-5, respectively, which could potentially limit the entrance of water and oxygen into the dump, hence reducing the leaching of heavy metals. We propose that these isolates represent an option for bioremediating contaminated waste by preventing both metallic dust from becoming airborne and rainwater from infiltrating into the waste. O. profundus KBZ 1-3 and O. profundus KBZ 2-5 isolated form Kabwe represent a novel species that has, for the first time, been applied in a bioremediation study.
  • Microbial induced slope surface stabilization using industrial-grade chemicals: A preliminary laboratory study
    Sivakumar Gothaman, Shumpei Mitsuyama, Kazunori Nakashima, Masahiro Komatsu, Satoru Kawasaki
    International Journal of GEOMATE 17 60 110 - 116 2019年08月 [査読有り][通常論文]
  • Zinc and Lead Biosorption by Oceanobacillus Profundus Kbz 3-2: a Bacterial Strain Resistant to Metals Isolated from Metal polluted Soils in Kabwe, Zambia
    Wilson Mwandira, Kazunori Nakashima, Satoru Kawasaki, Mayumi Ito, Tsutomu Sato, Toshifumi Igarashi, Meki Chirwa, Kawawa Banda, Imasiku Nyambe, Shouta Nakayama, Mayumi Ishizuka
    Proceedings of the 14th Asian Congress on Biotechnology (ACB2019) 2019年07月 [査読有り][通常論文]
  • Biological Control of Filament Formation Composed of Silica-polymerizing Enzymes
    Kazunori Nakashima, Junnosuke Okamoto, Satoru Kawasaki
    Proceedings of the 14th Asian Congress on Biotechnology (ACB2019) 2019年07月 [査読有り][通常論文]
  • Chitosan enhances calcium carbonate precipitation and solidification mediated by bacteria
    Thiloththama Hiranya Kumari Nawarathna, Kazunori Nakashima, Satoru Kawasaki
    International Journal of Biological Macromolecules 133 867 - 874 2019年07月 [査読有り][通常論文]
  • Bio-cementation for Slope Soil Stabilization againstSurface Erosion: A Bench-scale Preliminary Investigation
    S. Gowthaman, K. Nakashima, K. Ebina, S. Kawasaki
    Proceedings of the 53rd US Rock Mechanics/Geomechanics Symposium 2019年06月 [査読有り][通常論文]
  • Development of small scale biocemented rocks based on natural beachrock cement characteristics as a novel approach towards coastal erosion mitigation
    P. G. N. Nayanthara, A. B. N. Dassanayake, K. Nakashima, S. Kawasaki
    Proceedings of the 53rd US Rock Mechanics / Geomechanics Symposium 2019年06月 [査読有り][通常論文]
  • A minerochemical cement study of a beachrock slab: The case study of Peristeria, Salamis Island
    Saitis G, Evelpidou N, Kawasaki S, Koutsopoulou E, Komi A
    Proceedings of the 15th International Congress of the Goelogical Society of Greece 2019年05月 [査読有り][通常論文]
  • Ecofriendly calcium phosphate and calcium bicarbonate biogrouts
    Volodymyr Ivanov, Viktor Stabnikov, Satoru Kawasaki
    Journal of Cleaner Production 218 328 - 334 2019年05月 [査読有り][通常論文]
  • Efficacy of biocementation of lead mine waste from the Kabwe Mine site evaluated using Pararhodobacter sp.
    Wilson Mwandira, Kazunori Nakashima, Satoru Kawasaki, Mayumi Ito, Tsutomu Sato, Toshifumi Igarashi, Kawawa Banda, Meki Chirwa, Imasiku Nyambe, Shouta Nakayama, Mayumi Ishizuka
    Environmental Science and Pollution Research 26 15653 - 15664 2019年04月 [査読有り][通常論文]
  • Biogeotechnical approach for slope soil stabilization using locally isolated bacteria and inexpensive low-grade chemicals: A feasibility study on Hokkaido expressway soil, Japan
    Sivakumar Gothaman, Shumpei Mitsuyama, Kazunori Nakashima, Masahiro Komatsu, Satoru Kawasaki
    Soils and Foundations 59 2 484 - 499 2019年04月 [査読有り][通常論文]
  • Factors affecting the urease activity of native ureolytic bacteria isolated from coastal areas
    Md Al Imran, Kazunori Nakashima, Niki Evelpidou, Satoru Kawasaki
    Geomechanisc and Engineering, An International Journal 17 5 421 - 427 2019年04月 [査読有り][通常論文]
  • Biogeochemical simulation of microbially induced calcite precipitation with Pararhodobacter sp. strain SO1
    Masaru Akiyama, Satoru Kawasaki
    Acta Geotechnica 14 3 685 - 696 2019年03月 [査読有り][通常論文]
  • Environmental safety and biosafety in construction biotechnology
    Volodymyr Ivanov, Viktor Stabnikov, Olena Stabnikova, Satoru Kawasaki
    World Journal of Microbiology and Biotechnology 35 26 1 - 11 2019年02月 [査読有り][通常論文]
  • Ammonium-free carbonate-producing bacteria as an ecofriendly soil biostabilizer
    Keykha, H. A, Mohamadzadeh, H, Asadi, A, Kawasaki, S
    Geotechnical Testing Journal 42 1 19 - 29 2019年01月 [査読有り][通常論文]
  • Geological spatial plan toward groundwater resources in Kertek, Wonosobo Basin, Central Java, Indonesia
    L.R. Daryono, M.S.D. Wijayaningsih, A. Hendratno, M. Nukman, E. Hartantyo, S. Kawasaki
    Journal of Degraded and Mining Lands Management 6 2 1595 - 1608 2019年01月 [査読有り][通常論文]
  • Evaluating possible avenues for soil improvement by biocementation in Sri Lanka: A preliminary investigation
    P. G. N. Nayanthara, A. B, N. Dassanayake, Kazunori Nakashima, Satoru Kawasaki
    Proceedings of the Eighth International Conference of Geotechnique, Construction Materials and Environment (GEOMATE 2018) 759 - 764 2018年11月 [査読有り][通常論文]
  • Bio-inspired stabilization of embankment soil mediating Psychrobacillus sp. and low-grade chemicals: Preliminary laboratory investigation
    Sivakumar Gowthaman, Shumpei Mitsuyama, Kazunori Nakashima, Masahiro Komatsu, Satoru Kawasaki
    Proceedings of the Eighth International Conference of Geotechnique, Construction Materials and Environment (GEOMATE 2018) 163 - 168 2018年11月 [査読有り][通常論文]
  • Yuta Yoshimura, Kazunori Nakashima, Masaji Kato, Kengo Inoue, Fumiyoshi Okazaki, Hitoshi Soyama, Satoru Kawasaki
    ACS Omega 3 11 15267 - 15271 2018年11月 [査読有り][通常論文]
     
    Single-chamber microbial fuel cells (MFCs) were constructed using rice bran (carbon source) and pond bottom mud (microbial source). The total electric charge obtained in the MFC combining rice bran with pond bottom mud was four times higher than that in MFC using only rice bran. Phylogenetic analyses revealed dominant growth of fermentative bacteria such as Bacteroides and Clostridium species, and exoelectrogenic Geobacter species in the anode biofilms, suggesting that mutualism of these bacteria is a key factor for effective electricity generation in the MFC. Furthermore, rice bran, consisting of persistent polysaccharide, was pretreated by the hydrodynamic cavitation system to improve the digestibility and enhance the efficiency in MFC, resulting in 26% increase in the total production of electricity.
  • Bio-based cementation using urease-producing bacteria: Sand solidification and kinetics
    K. Nakashima, M. Fujita, T. H. K. Nawarathna, S. Kawasaki
    New Biotechnology 44 s154  2018年10月 [査読有り][通常論文]
  • Comparative characteristics of cement materials in natural and artificial beachrocks using a petrographic method
    L. R. Daryono, A. D. Titisari, I. W. Warmada, S. Kawasaki
    Bulletin of Engineering Geology and the Environment 2018年09月 [査読有り][通常論文]
  • Effects of various factors on carbonate particle growth using ureolytic bacteria
    Md. Al Imran, Mai Shinmura, Kazunori Nakashima, Satoru Kawasaki
    Materials Transactions 59 9 1520 - 1527 2018年09月 [査読有り][通常論文]
  • A preliminary investigation on isolation and identification of marine bacteria for biocementation in nearshore environments
    Nayanthara P. G. N, Dassanayake A. B. N, Nakashima K, Kawasaki S
    Proceedings of International Symposium on Earth Resources Management and Environment, ISERME 2018 111 - 118 2018年08月 [査読有り][通常論文]
  • Experimental optimization of biocement formation: Alternative countermeasure for surface erosion of cut slope
    Gowthaman S, Nakashima K, Ebina K, Kawasaki S
    Proceedings of International Symposium on Earth Resources Management and Environment, ISERME 2018 97 - 103 2018年08月 [査読有り][通常論文]
  • Soil improvement using plant-derived urease-induced calcium carbonate precipitation
    R. A. N. Dilrukshi, Kazunori Nakashima, Satoru Kawasaki
    Soils and Foundations 58 4 894 - 910 2018年08月 [査読有り][通常論文]
  • Applicability of coastal ureolytic bacteria to coastal protection in Greece
    Md. Al Imran, Kazunori Nakashima, Niki Evelpidou, Satoru Kawasaki
    2018 International Conference on Geomechanics and Engineering (ICGE18) 2018年08月 [査読有り][通常論文]
  • Effects of cationic polypeptide on CaCO3 crystallization and sand solidification by microbial-induced carbonate precipitation
    Thiloththama H. K. Nawarathna, Kazunori Nakashima, Masahiro Fujita, Momoko Takatsu, Satoru Kawasaki
    ACS Sustainable Chemistry and Engineering 6 8 10315 - 10322 2018年07月 [査読有り][通常論文]
  • Assessment of groundwater facies in Wates coastal area, Kulon Progo, Yogyakarta, Indonesia
    Phyu Phyu Thin, Heru Hendrayana, Wahyu Wilopo, Satoru Kawasaki
    Journal of Degraded and Mining Lands Management 5 4 1389 - 1401 2018年07月 [査読有り][通常論文]
  • Sivakumar Gowthaman, Kazunori Nakashima, Satoru Kawasaki
    Materials 11 4 553  2018年04月04日 [査読有り][通常論文]
     
    Incorporating sustainable materials into geotechnical applications increases day by day due to the consideration of impacts on healthy geo-environment and future generations. The environmental issues associated with conventional synthetic materials such as cement, plastic-composites, steel and ashes necessitate alternative approaches in geotechnical engineering. Recently, natural fiber materials in place of synthetic material have gained momentum as an emulating soil-reinforcement technique in sustainable geotechnics. However, the natural fibers are innately different from such synthetic material whereas behavior of fiber-reinforced soil is influenced not only by physical-mechanical properties but also by biochemical properties. In the present review, the applicability of natural plant fibers as oriented distributed fiber-reinforced soil (ODFS) and randomly distributed fiber-reinforced soil (RDFS) are extensively discussed and emphasized the inspiration of RDFS based on the emerging trend. Review also attempts to explore the importance of biochemical composition of natural-fibers on the performance in subsoil reinforced conditions. The treatment methods which enhances the behavior and lifetime of fibers, are also presented. While outlining the current potential of fiber reinforcement technology, some key research gaps have been highlighted at their importance. Finally, the review briefly documents the future direction of the fiber reinforcement technology by associating bio-mediated technological line.
  • Fly ash incorporated with biocement to improve strength of expansive soil
    Mengmeng Li, Chaolin Fang, Satoru Kawasaki, Varenyam Achal
    Scientific Reports 8:2565 2018年02月 [査読有り][通常論文]
  • Mengmeng Li, Chaolin Fang, Satoru Kawasaki, Minsheng Huang, Varenyam Achal
    International Biodeterioration and Biodegradation 141 94 - 100 2018年 [査読有り][通常論文]
     
    Microbially induced carbonate precipitation (MICP) is one of techniques for consolidation of cementitious materials however, limited biodiversity and inadequate information on its application suggests further extensive research in this area. In this study, bacteria with ability to precipitate carbonate, preferably CaCO3, were isolated from Yixing Shanjuan Cave, China after analyzing bacterial diversity using Illumina MiSeq sequencing the V3-V4 region of 16S rRNA gene. A total of 58,712 effective 16S rRNA gene sequences were obtained, classified into 31 bacterial phyla. One of the highest urease-producing bacterium, Acinetobacter sp. SC4, was then used in consolidation of cracks created in masonry cement mortars. The bio-consolidation led to significant improvement in compressive strength and reduction in water absorption of mortars. It formed calcite observed under scanning electron microscopy, which were in agreement with X-ray diffraction and thermogravimetric analysis. The presented work is the first extensive study on Acinetobacter sp. induced carbonate precipitation in MICP related research.
  • Thiloththama Hiranya Kumari Nawarathna, Kazunori Nakashima, Satoru Kawasaki
    International Journal of GEOMATE 14 41 7 - 12 2018年 [査読有り][通常論文]
     
    Microbially induced carbonate precipitation (MICP) by using ureolytic bacteria is a novel and environmentally friendly way to treat the un-cemented sand. It was implemented successfully in number of geotechnical applications. Use of organic additives to improve the MICP process is a novel and interesting approach. In this research, effect of the cationic biopolymer poly-l-lysine on the MICP process was investigated by using ureolytic bacteria Pararhodobacter sp. Urea hydrolysis by the bacteria in the presence of CaCl2 was conducted with the addition of the polymer under different conditions. Morphology of the precipitate of CaCO3 after oven dried was analyzed by using the scanning electron microscope. Bell-shaped curve was obtained for the variation between the amount of the precipitate with the increase of the amount of the poly-l-lysine. Poly-L-lysine gives higher amount of precipitate than conventional MICP process and morphology of the crystals changed drastically from well-developed rhombohedral crystals to ellipsoidal shaped aggregates.
  • G. G.N.N. Amarakoon, Satoru Kawasaki
    Materials Transactions 59 1 72 - 81 2018年 [査読有り][通常論文]
     
    Biomineralization is an environmentally friendly technology for improving soil-engineering properties. One of the most common biomineralization processes is microbially induced calcite precipitation (MICP). In this study, sand solidification tests were conducted using Pararhodobacter sp., which is a local ureolytic bacteria obtained from the sand near beach rock in Okinawa, Japan. The goal of this study was to solidify a specimen having an estimated unconfined compressive strength (UCS) of more than several MPa to improve soil properties and investigate the influence of various factors on the engineering properties of treated soil catalyzed by ureolytic bacteria (curing temperature, injection interval of cementation solution, Ca2+ concentration, curing time, bacterial population, re-injection of bacteria and particle size of sand). Model test specimens were cemented up to an estimated UCS of 10 MPa after 14 days under the following conditions: a curing temperature of 30°C, an injection interval of 1 day, and a Ca2+ concentrations in cementation solution of 0.5 M. Multiple regression analysis showed that the relevant conditions for estimating UCS were test period, D (days), and Ca2+ concentration of the cementation solution, Cca (M). The formula for predicting the estimated UCS (qeu (MPa)) was qeu = 13.99 Cca + 0.37 D-0.09. Overall, the results of this study will contribute to the application of a new technique to sand improvement and bio-stimulation.
  • Wilson Mwandira, Kazunori Nakashima, Satoru Kawasaki
    ECOLOGICAL ENGINEERING 109 Part A 57 - 64 2017年12月 [査読有り][通常論文]
     
    Lead (Pb2+) is a toxic heavy metal that has a severe negative effect on human health and the environment. Physical, chemical and biological remediation techniques have long been used to remediate lead contamination. However, because of the great danger posed by lead contamination, there is increasing interest to apply ecofriendly and sustainable methods to remediate lead. Therefore, this study was conducted to use the microbially induced calcium carbonate precipitation (MICP) technique in conjunction with the bacterium Pararhodobacter sp. to bioremediate lead. Laboratory scale experiments were conducted and complete removal of 1036 mg/L of Pb2+ was achieved. These results were further confirmed by scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis, which indicated coprecipitation of calcium carbonate (CaCO3) and lead. The unconfined compressive strength increased with an increase in injection interval with maximum unconfined compressive strength of 1.33 MPa for fine sand, 2.87 MPa for coarse sand and 2.80 MPa for mixed sand. For Pararhodobacter sp. to efficiently induce lead immobilisation the bacterial interval required is four times with a calcium and urea concentration of 0.5 M and bacterial concentration of 109 cfu/mL. Very few low-cost in situ heavy metal treatment processes for lead bioremediation are available; therefore, bioimmobilization of lead by MICP has the potential for application as a low-cost and eco-friendly method for heavy metal remediation.
  • Microbially induced carbonate precipitation for expressway slope protection
    Mitsuyama, S, Nakashima, K, Komatsu, M, Kawasaki, S
    Abstract Proceedings of the 1st International KAMPAI Symposium on Sustainable Management of Resources and Environment in the 21st Century 23  2017年11月 [査読有り][通常論文]
  • Effect of cationic bio-polymer on CaCO3 crystallization by microbe
    T.H.K. Nawarathna, Kazunori Nakashima, Satoru Kawasaki
    Abstract Proceedings of the 1st International KAMPAI Symposium on Sustainable Management of Resources and Environment in the 21st Century 24  2017年11月 [査読有り][通常論文]
  • Immobilization of Lead-Contaminated Mine Waste by Pararhodobacter sp.
    Mwandira, W, Nakashima, K, Kawasaki, S, Chirwa, M, Banda, K.E, Nyambe, I.A
    Abstract Proceedings of the 1st International KAMPAI Symposium on Sustainable Management of Resources and Environment in the 21st Century 39  2017年11月 [査読有り][通常論文]
  • Effect of Organic biopolymer on the microbially induced carbonate precipitation and its morphology
    Thiloththama Hiranya Kumari Nawarathna, Kazunori Nakashima, Satoru Kawasaki
    Proceedings of the Seventh International Conference of Geotechnique, Construction Materials and Environment (GEOMATE 2017) 7 1 719 - 724 2017年11月 [査読有り][通常論文]
  • Usefulness of artificial beachrock and geotextile tube technology
    Md. Al Imran, Kazanori Nakashima, Satoru Kawasaki
    Proceedings of the Seventh International Conference of Geotechnique, Construction Materials and Environment (GEOMATE 2017) 7 1 423 - 428 2017年11月 [査読有り][通常論文]
  • 秋山 克, 川﨑 了
    地盤工学ジャーナル 12 3 337 - 349 公益社団法人 地盤工学会 2017年09月 [査読有り][通常論文]
     
    尿素分解型バイオグラウトを用いたシリンジ固化試験に対し,固化反応に関する現況再現解析ならびに再現精度向上のためのパラメータ調整を実施した。ウレアーゼ活性試験に基づく再現解析で得られた,尿素分解菌Pararhodobacter sp. strain SO1の尿素分解反応の反応速度定数は1×10-8 mol/mg/sec,半飽和定数は0.635 mol/Lとなった。鉱物析出解析の結果より,実測と解析の析出鉱物を整合させるために,カルサイトのみが析出する設定とした。シリンジ固化試験再現の逐次解析において,反応に寄与する微生物量を考慮した「調整指数」の導入により,排出されるCa2+濃度の変化を再現できた。以上の結果は,尿素分解型バイオグラウトのカルサイト析出に関わる微生物反応シミュレーションを実施することによって,施工時の強度発現の予測や施工管理が可能であることを示している。
  • Efect of organic bio-polymer on bio-mineralization of CaCO3
    T.H.K. Hiranya, Kazunori Nakashima, Satoru Kawasaki
    Proceedings of International Symposium on Earth Resources Management and Environment, ISERME 2017 59 - 66 2017年08月 [査読有り][通常論文]
  • Bioremediation of lead-contaminated mine waste using microbially induced carbonate precipitation
    Wilson Mwandira, Kazunori Nakashima, Satoru Kawasaki
    Proceedings of International Symposium on Earth Resources Management and Environment, ISERME 2017 21 - 25 2017年08月 [査読有り][通常論文]
  • Masahiro Fujita, Kazunori Nakashima, Varenyam Achal, Satoru Kawasaki
    BIOCHEMICAL ENGINEERING JOURNAL 124 1 - 5 2017年08月 [査読有り][通常論文]
     
    Pararhodobacter sp. SW is a urease-producing bacterium and can be used for microbial induced calcium carbonate precipitation (MICP). In the present study, microbial cells are directly used for the analysis of urease activity without extraction or purification of urease. The whole-cell evaluation of the bacteria provides important and comprehensive information on urease activity because the bacterial cells are directly used in biomineralization process. The urease activity of Pararhodobacter sp. increased with cell growth during cultivation and the bacteria maintained its enzyme activity even after 15-days culture. High urease activity was obtained at relatively high temperature around 60 degrees C and neutral pH around 8. It is revealed that urease was not secreted in culture medium but would accumulate in/on the cell, and resuspended cells obviously showed urease activity. Meanwhile, the enzyme activity was detected in a soluble fraction of cell lysate. Furthermore, clear band based on urease activity was observed in soluble fraction of cell lysate in native PAGE analysis followed by activity staining. These findings will contribute to the efficient biocementation using this ureolytic bacteria. (c) 2017 Elsevier B.V. All rights reserved.
  • Solubilization and functional evaluation of silica-polymerizing enzyme
    Hidetoshi Oguri, Kazunori Nakashima, Satoru Kawasaki
    The 13th the Asian Congress on Biotechnology 2017 (ACB2017) 2017年07月 [査読有り][通常論文]
  • Md. Al Imran, Kazunori Nakashima, Satoru Kawasaki
    International Journal of GEOMATE 13 39 67 - 72 2017年 [査読有り][通常論文]
     
    In recent years, traditional forms of river and coastal structures have become very expensive to build and maintain, because of the shortage of natural rock. Therefore, the materials used in hydraulic and coastal structures are changing from traditional rubble and concrete systems to cheaper, sustainable, and eco-friendly materials and systems such as artificial rock, gabion, slags, geosynthetics, and so on. Moreover, shorelines are being continually eroded by the wave action of the sea, and the river and coastal structures are frequently damaged by both anthropogenic and natural causes such as over wash and storm. How to deal with eroding coastal problems is a main topic of this article. Recently, artificial beachrock and geotextile tube technology has changed from being an alternative construction technique and, in fact, has advanced to become the prime solution of choice. Therefore, the objectives of the present study is to find out the feasibility to protect coastal erosion in Asia along with using artificial beachrock and geotextile tube technology in a cheaper, sustainable and eco-friendly way.
  • Shumpei Mitsuyama, Kazunori Nakashima, Satoru Kawasaki
    International Journal of GEOMATE 12 31 71 - 76 2017年 [査読有り][通常論文]
     
    Biogrouting is a method employed for ground improvement based on microbially induced calcium carbonate precipitation. It is commonly believed that biogrout has environmental and economic benefits. However, there remains the need to clearly understand the internal structure of biogrouted soil. In this study, we use microfocus X-ray computed tomography (CT) to evaluate the porosity in biogrouted sand. X-ray CT is useful as a non-distractive inspection tool. First, we prepare small specimens using coral sand at different dilution rates of culture solution. After carrying out a solidification test for 2 wks., we perform an unconfined compressive strength (UCS) test and measure the porosity of the specimens. Our aim is to investigate the influence of the dilution rate on the UCS and the porosity of sand specimens. The results show that a lower dilution rate resulted in a lower sand-specimen porosity and an increase in the UCS. We investigate the precipitation that fills a void. Then, we investigate the relationship between UCS and the ratio of porosity. There was a negative correlation between UCS and porosity, which closely agrees with previous research. We confirm the validity of the result, and we determine the UCS from the porosity.
  • Zeinab Bakhshipour, Afshin Asadi, Bujang B. K. Huat, A. Sridharan, Satoru Kawasaki
    SOILS AND FOUNDATIONS 56 6 1008 - 1020 2016年12月 [査読有り][通常論文]
     
    In this study, the effect of acid rain on the physico-chemical and microstructural properties of two different residual soils was investigated. In order to reproduce the process of soil-acid rain-chemical interaction, an infiltration setup was fabricated. The samples were then infiltrated by different pH levels of acid rain, and for different fluxes of acid rain equivalent to the precipitation, for 1-20 years. The compressive strength, consistency limit, compaction characteristics, and coefficient of permeability were evaluated, to investigate the mechanical changes of the soils after being exposed to acid rain. In addition, zeta potential, atomic adsorption spectroscopy (AAS), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX) were carried out to identify the underlying controlling mechanisms. The results showed that low pH and high fluxes of acid rain led to a reduction in soil strength and maximum dry density as well as an increase in the coefficient of permeability, liquid limit, and optimum moisture content of the soil. The SEM, EDX, and atomic absorption analysis of the soils confirmed the reduction in the concentration of elements, and the loose structure for both soils due to the effects of acid rain. (C) 2017 The Japanese Geotechnical Society. Production and hosting by Elsevier B.V.
  • Evaluation of porosity in biogrouted sand using microfocus X-ray CT
    Shumpei Mitsuyama, Kazunori Nakashima, Satoru Kawasaki
    Proceedings of the Sixth International Conference of Geotechnique, Construction Materials and Environment (GEOMATE 2016) 145 - 150 2016年11月 [査読有り][通常論文]
  • Effects of various powders on strength reinforcement of calcium phosphate compounds precipitated in sand specimens
    Dilrukshi, R.A.N, Kawasaki, S
    Abstract Proceedings of International Doctoral Symposium on Sustainable Management of Resources and Environment in the 21st Century 8  2016年11月 [査読有り][通常論文]
  • Anthropogenic Beachrock for Eco-Environment Shoreline Development
    L. R. Daryono, A. D. Titisari, I. W. Warmada, S. Kawasaki
    The 2nd International Conference on Science and Technology 2016 (ICST2016) 2016年10月 [査読有り][通常論文]
  • Strength reinforcement of sand test specimens cemented with calcium phosphate compounds and different powders
    R.A.N. Nadeeka, S. Kawasaki
    Proceedings of the 9th Asian Rock Mechanics Symposium ARMS9-RMC3-P86  2016年10月 [査読有り][通常論文]
  • Coral sand solidification test through microbial calcium carbonate precipitation using Pararhodobacter sp.
    Md. Nakibul, Hasan Khan, S. Shimazaki, S. Kawasaki
    International Journal of GEOMATE 11 26 2665 - 2670 2016年10月 [査読有り][通常論文]
  • Comparison of Cementation Mechanism between Natural Beachrock and Anthropogenic Beachrock, Case Study: Okinawa Island, Japan
    L. R. Daryono, A. D. Titisari, I. W. Warmada, S. Kawasaki
    The 41st Scientific Annual Meeting of Indonesian Association of Geophysicists PITHAGI2016-042  2016年09月 [査読有り][通常論文]
  • Plant-derived urease induced sand cementation used in geotechnical engineering applications
    R. A. N. Dilrukshi, S. Kawasaki
    Proceedings of the International Conference on Geomechanics, Geo-energy and Geo-resources IC3G 2016 Theme 7-100 - Theme 7-107 2016年09月 [査読有り][通常論文]
  • Strengthening of sand cemented with calcium phosphate compounds using plant-derived urease
    R. A. N. Dilrukshi, Jun Watanabe, Satoru Kawasaki
    International Journal of GEOMATE 11 25 2461 - 2467 2016年09月 [査読有り][通常論文]
  • Development of biogrouting using plant-derived urease and calcium phosphate compound
    M. Takatsu, R. A. N. Dilrukshi, S. Kawasaki
    Proceedings of the 50th US Rock Mechanics / Geomechanics Symposium ARMA 16-471  2016年06月 [査読有り][通常論文]
  • Soil reinforcement using calcium phosphate compounds
    S. Kawasaki, M. Akiyama
    ASEAN Engineering Journal, Part C 5 1 5 - 13 2016年06月 [査読有り][招待有り]
  • Atsuko Sato, Satoru Kawasaki, Toshiro Hata, Toshihiro Hayashi
    International Journal of GEOMATE 10 22 2071 - 2076 2016年06月 [査読有り][通常論文]
     
    Peaty soil is widely distributed in Hokkaido. Untreated, it is too soft for use as a civil engineering material. Soil solidification improvement technologies that harness the metabolism of microbes in soil have recently been gaining attention. Such research and development has proceeded within and beyond Japan. The researchers investigated a technology for peat solidification that harnesses the ability of microbes inhabiting the soil of construction sites to precipitate calcium carbonate, and consideration was given to solidifying peaty soil by harnessing the ability of those microbes. Focusing on the urease activity of microbes, which has an influence on solidification of peaty soil, a soil solidification test, in which the metabolism of microbes was utilized, and an experiment, in which the degree of solidification of peaty soil was tested, were done by using peaty soil samples from Hokkaido. The two experiments found the following. 1) Microbes that have urease activity inhabit the peaty soil of Hokkaido. 2) It is possible to solidify peaty soil by enhancing the urease activity of these microbes. 3) It is possible to evaluate the degree of urease activity in peaty soil by measuring its electric conductivity.
  • Study of beachrocks in East Attica
    A. Karkani, N. Evelpidou, H. Maroukian, S. Kawasaki
    Bulletin of the Geological Society of Greece 50 1 434 - 440 2016年05月 [査読有り][通常論文]
  • Varenyam Achal, Satoru Kawasaki
    FRONTIERS IN MICROBIOLOGY 7 314 2016年03月 [査読有り][通常論文]
  • Takashi Danjo, Satoru. Kawasaki
    MATERIALS TRANSACTIONS 57 3 428 - 437 2016年03月 [査読有り][通常論文]
     
    To develop an alternative ground improvement technique in coastal areas based on bio-stimulation, we investigated sand cementation using bacteria that have been shown to enhance beachrock formation. We conducted cementation tests using Pararhodobacter sp. strain SO1, a local ureolytic bacteria originating from the sand near beachrock in Okinawa, Japan. Specifically, we attempted to cement sand specimens to unconfined compressive strength (UCS) of several MPa and establish the influence of several test conditions (curing temperature, injection interval of cementation solution, Ca2+ concentration and sodium malate concentration in the cementation solution, and test period) on the UCS. Column specimens were cemented up to UCS of 10 MPa after 28 days under the conditions (curing temperature; 30 degrees C, injection interval; 1 day, Ca2+ concentrations in cementation solution; 0.3 M). Multiple regression analysis showed that the relevant conditions for UCS were test period, D (days), and Ca2+ concentration of the cementation solution, C-ua (M). The prediction formula for UCS, q(ud) (MPa), was experimentally determined to be q(ud) = 48.3C(ca) + 0.456D - 19.51. Overall, the results of this study will contribute to the application of a new technique for coastal sand improvement and bio-stimulation.
  • Sand solidification through microbially induced carbonate precipitation for erosion control: Prospects in Bangladesh
    M. N, H. Khan, S. Kawasaki, M. R. Hassan
    Journal of Environmental Science and Natural Resources 9 1 59 - 61 2016年 [査読有り][通常論文]
  • R. A.N. Dilrukshi, S. Kawasaki
    Geotechnical Special Publication 2016- 269 104 - 115 2016年 [査読有り][通常論文]
     
    The effect of pH increasing ability of plant-derived urease to induce the precipitation of calcium phosphate compounds (CPCs) as CPC-biogrout (CPC-Bio) and addition of powder materials to induce the precipitation of CPCs as CPC-chemical grout (CPC-Chem) was examined separately using unconfined compressive strength (UCS) test for applying as novel, eco-friendly ground improvement methods. Initially, Toyoura sand test pieces were cemented only from CPC solutions made from stock solutions of calcium acetate and di-potassium phosphate. Subsequent sand test pieces were cemented by different concentrations of urea and CPC solution, and concentration fixed watermelon seeds extract. All test pieces were cured in an airtight container at high humidity at 25°C. Furthermore, the UCS on sand test pieces cemented with same stock solutions mentioned above with different powders such as tricalcium phosphate (TCP), magnesium phosphate (MgP), calcium carbonate (CC) and magnesium carbonate (MgC) were conducted. Maximum UCS of greater than 100 kPa was obtained after 28 days of curing for both CPC-Bio and CPC-Chem and obtained UCS was higher than the UCS of test pieces made only from CPC. pH for optimal cementation was around 8.0 and the best Ca/P ratio in CPC solutions producing the highest cementation was 0.5 for CPC-Bio.
  • G. G.N.N. Amarakoon, S. Kawasaki
    Geotechnical Special Publication 2016- 269 72 - 83 2016年 [査読有り][通常論文]
     
    Bio-mineralization is an environment-friendly technology to improve soil engineering properties. One of common bio-mineralization processes is microbially induced calcite precipitation (MICP). A series of laboratory tests was conducted to produce solidification of the specimen having an estimated unconfined compressive strength (UCS) of more than several MPa, and investigate the influence of varies factors on soil properties treated with MICP. A solidification test was conducted using a syringe (30 mL) on different particle size of Mikawa sand (mean diameter: 0.6mm) and Toyoura sand (mean diameter: 0.2mm) using local ureolytic bacteria: Parahadobactor sp. isolated in Japan. The bacteria were grown up for 72 hours to increase the optical density (OD) of 600 nm (OD600). The cementation media was added and the solidification test was conducted until 14 days. After that, needle penetration tests were conducted to obtain the estimated UCS value of the specimen. The results indicated that the estimated UCS value was exceeded 3 MPa for three Mikawa sand samples: (1) sample treated by 1.0g of bacteria re-injected bacterial solution after 7 days, (2) sample treated by 1.0g of bacteria without re-injection after 7 days, and (3) sample treated with 0.1g of bacteria with re-injection.
  • 尿素分解菌を用いた地盤固化に関する実験的研究
    八重樫 彩, 檀上 尭, 川﨑 了
    第44回岩盤力学に関するシンポジウム講演集 268 - 272 2016年01月 [査読無し][通常論文]
  • Effective use of plant-derived Urease in the field of geoenvironmental/geotechnical engineering
    R. A. N. Dilrukshi, Satoru Kawasaki
    Journal of Civil and Environmental Engineering 6 1 2016年01月 [査読有り][通常論文]
  • 佐藤厚子, 川﨑 了, 畠 俊郎, 山梨高裕, 西本 聡
    土木学会論文集C(地圏工学) 71 4 427 - 439 2015年12月 [査読有り][通常論文]
  • Artificial beachrock formation through sand solidification towards the inhibit of coastal erosion in Bangladesh
    Md. Nakibul, Hasan Khan, Takashi Danjo, Satoru Kawasaki
    International Journal of GEOMATE 9 2 1528 - 1533 2015年12月 [査読有り][通常論文]
  • Mechanical property of sand cemented with calcium phosphate compounds using plant-derived urease
    R. A. N. Dilrukshi, J. Watanabe, S. Kawasaki
    Proceedings of the Fifth International Conference of Geotechnique, Construction Materials and Environment (GEOMATE 2015) 84 - 89 2015年11月 [査読有り][通常論文]
  • Estimating urease activity in microorganism of peat based on electric conductivity
    A. Sato, S. Kawasaki, T. Hata, T. Yamanashi
    Proceedings of the Fifth International Conference of Geotechnique, Construction Materials and Environment (GEOMATE 2015) 426 - 429 2015年11月 [査読有り][通常論文]
  • Coral sand solidification test through microbial carbonate precipitation using Pararhodobacter sp.
    Md. Nakibul, Hasan Khan, S. Shimazaki, S. Kawasaki
    Proceedings of the Fifth International Conference of Geotechnique, Construction Materials and Environment (GEOMATE 2015) 131 - 137 2015年11月 [査読有り][通常論文]
  • Mengmeng Li, Qing-Long Fu, Qiuzhuo Zhang, Varenyam Achal, Satoru Kawasaki
    SCIENTIFIC REPORTS 5 2015年11月 [査読有り][通常論文]
     
    Bio-grout, a new ground improvement method, has been recently developed to improve the mechanical properties, decrease the permeability of porous materials, reinforce or repair cementitious materials and modify the properties of soil or sand. Bio-grout production depends on microbially induced calcite precipitation (MICP), which is driven mainly by an enzyme, urease. However, urease-based MICP process produces excessive ammonia, in addition to secondary pollution generated by urea that is used as substrate in it. In the present study, we reported asparaginase-based MICP process for sand bio-grout development using Bacillus megaterium, and results were also compared with urease-based bio-grouts. The asparaginase activity led to significantly less ammonia production compared to urease without compromising with desired properties of a novel grout. The UCS of bio-grout was obtained at 980 kPa, while the permeability was decreased substantially. The mineralogical composition of precipitated substance was identified as calcite using XRD and the crystal morphology was observed under SEM. The mass percentage of calcite in bio-grout was calculated by thermogravimetric analysis and XCT verified calcite precipitation in it. The results confirmed that biocalcification by means of bacterial asparaginase is a potential solution for geotechnical problems. The asparaginase-based MICP process could be of wider acceptance in future.
  • Md. Nakibul Hasan Khan, G. G. N. N. Amarakoon, Suguru Shimazaki, Satoru Kawasaki
    MATERIALS TRANSACTIONS 56 10 115 - 122 2015年10月 [査読有り][通常論文]
     
    Artificial beachrock, formed by coral sand solidification through microbially induced carbonate precipitation (MICP), could provide coastal protection instead of concrete structures, and would be eco-friendly as well as help minimize costs. The present study was conducted to solidify coral sand through the MICP method by using an ureolytic bacterium (Parahodobacter sp.) isolated from peripheral beachrock. The goal was to obtain a sample with an unconfined compressive strength (UCS) of 20 MPa or more. We also aimed to examine the growth characteristics of this bacterium in the culture medium ZoBell2216E, which is commonly used for marine bacteria. In order to determine the suitability of the MICP test, growth properties of the microbial strain were observed under various culture conditions. A sand solidification test with MICP was carried out in a syringe as well as a PET cylinder. The strength of the resulting specimens was measured with the needle penetration test. The specimen solidified up to 20 MPa of the estimated UCS after 21 days of curing. For optimum growth of the bacterium, 1.0 g of the culture was added to 100 mL culture media and incubated with shaking at 160 rpm. The preferred final concentration in solidification promoting solution of both urea and CaCl2 was 0.5 M, with bacterial cell densities of 10(9) CFU/mL. In order to efficiently induce solidification, the optimum pH was 7.0 or higher, and Ca2+ concentration was maintained at 1.0 g/L. The results were enhanced by re-injecting the culture solution when the pH and Ca2+ concentrations in the specimen were not in the ideal ranges indicated above.
  • 荒牧憲隆, 玉村修司, 田中 翔, 川﨑 了, 藤井義明, 金子勝比古
    地盤工学ジャーナル 10 3 391 - 401 2015年09月 [査読有り][通常論文]
  • R. A. N. Dilrukshi, Jun Watanabe, Satoru Kawasaki
    MATERIALS TRANSACTIONS 56 9 1565 - 1572 2015年09月 [査読有り][通常論文]
     
    The investigation of urease containing plant species and the calcium phosphate compounds (CPCs) precipitation along with plant derived urease were performed at laboratory scale. At first, small scale laboratory samples (height, h = 10 cm & inner diameter, phi = 5 cm) were made using Toyoura sand and only from CPC solution having different Ca/P ratios to use as control samples. Afterward, another Toyoura sand test pieces were made by mixing watermelon seed extract, urea with different concentrations and CPC solution having different Ca/P ratios to study the optimal cementation. Test pieces were cured up to 28 days in an airtight container at high humidity at 25 degrees C and carried out unconfined compressive strength (UCS) test. The UCS of the sand test pieces cemented by CPC with urease containing plant extract and urea were larger than that of the test pieces without plant extract. Furthermore, the best CPC solution mixture for highest cementation was with the concentration of Ca/P ratio of 0.5. In addition, pH content was measured after UCS test. Maintaining pH around 8 in the specimen at 28 days was significant to get optimal cementation.
  • Compressive strength of sand cemented with calcium phosphate compound
    G. G. N, N. Amarakoon, S. Kawasaki
    Proceedings of the International Conference on Geotechnical Engineering ICGE Colombo 2015 197 - 200 2015年08月 [査読有り][通常論文]
  • 川﨑 了
    Journal of MMIJ 131 5 155 - 163 2015年05月 [査読有り][通常論文]
  • Novel microbial based low energy green building material production technology
    Mengmeng Li, Satoru Kawasaki, Qiuzhuo Zhang, Varenyam Achal
    Advanced Materials Research 1090 96 - 100 2015年02月 [査読有り][通常論文]
  • T. Danjo, S. Kawasaki, S. Shimazaki, K. Koizuka
    Geomechanics from Micro to Macro, Vols I and II 1521 - 1526 2015年 [査読有り][通常論文]
     
    The use of an artificial rock modelled on beachrock is considered a novel eco-friendly countermeasure to preserve coastlines. Beachrock consists of coastal sediments from within the intertidal zone that have been cemented mainly by CaCO3. In this study, a solidification test was conducted on coral sand using local ureolytic bacteria based on a beachrock formation mechanism previously investigated at Okinawa, Japan. The experiment aimed to produce solidification of the specimen to an Unconfined Compressive Strength (UCS) of more than several MPa (1/10-1/5 of the UCS value of ordinal concrete and beachrock). Results showed that using Pararhodobacter sp., found near beachrock in Okinawa, Japan, the specimen solidified to 6.7 MPa UCS after 28 days of curing. The solidification mechanism was the stimulation of ureolysis by the bacteria and the precipitation of aragonite between sand particles.
  • Md. Nakibul H. Khan, Satoru Kawasaki
    15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability 1123 - 1127 2015年 [査読有り][通常論文]
     
    Erosion in the coastal area of Bangladesh is a big point of concern. The present study was conducted to find out the protective measure from coastal erosion in Bangladesh as well as evaluate the prospects of the formation of artificial beachrock. This study was conducted based on literature survey of related works. In the coast of Bangladesh, average recession through erosion will occur 0.87m due to per 1cm sea level rise. Beachrock as well as artificial beachrocks have the potentiality to prevent such coastal erosion. Beachrock is a type of sedimentary deposit that generally occurs on the tropical and subtropical beaches as a result of intertidal lithification of loose beach sands and gravels by carbonate cementation. Beachrock in the world differs by their chemical composition but it composed mainly of CaCO3, SiO2 and Al2O3. Usually, beachrocks are formed by the cementation of CaCO3 precipitation with the influence of seawater and/or seawater evaporation as well as surface microorganisms. From the knowledge of natural beachrock formation as well as sand properties, in the future, it may possible to manufacture artificial beachrocks similar to beachrocks for erosion control purposes in Bangladesh.
  • Effect on unconfined compressive strength of sand test pieces cemented with calcium phosphate compound
    G. G. N, N. Amarakoon, T. Koreeda, S. Kawasaki
    International Journal of GEOMATE 7 2 1069 - 1074 2014年12月 [査読有り][通常論文]
  • Effect on unconfined compressive strength of sand test pieces cemented with calcium phosphate compound by addition of scallop shell powder
    G. G. N, N. Amarakoon, T. Koreeda, S. Kawasaki
    Proceedings of the Fourth International Conference on Geotechnique, Construction Materials and Environment (GEOMATE 2014) 50 - 55 2014年11月 [査読有り][通常論文]
  • Improvement in the unconfined compressive strength of sand test pieces cemented with calcium phosphate compound
    G. G. N, N. Amarakoon, T. Koreeda, S. Kawasaki
    Proceedings of the 8th Asian Rock Mechanics Symposium 276 - 282 2014年10月 [査読有り][通常論文]
  • Effects of bacterial ureolysis and seawater evaporation on beachrock formation
    T. Danjo, S. Kawasaki, S. Shimazaki, K. Koizuka
    Proceedings of the 8th Asian Rock Mechanics Symposium 270 - 275 2014年10月 [査読有り][通常論文]
  • Microstructure of brown coal in hydrogen peroxide solution observed by employing X-ray computed tomography
    N. Aramaki, S. Tamamura, S. Shimizu, A. Ueno, Y. Ohmi, K. Kaneko, S. Tanaka, S. Kawasaki
    Proceedings of the 8th Asian Rock Mechanics Symposium 1579 - 1588 2014年10月 [査読有り][通常論文]
  • Effect of liquefaction countermeasures for sand cemented by microbial metabolism
    Y. Inagaki, M. Tsukamoto, T. Sasaki, S. Kawasaki
    Proceedings of the 8th Asian Rock Mechanics Symposium 920 - 929 2014年10月 [査読有り][通常論文]
  • G. G. N. N. Amarakoon, Takefumi Koreeda, Satoru Kawasaki
    MATERIALS TRANSACTIONS 55 9 1391 - 1399 2014年09月 [査読有り][通常論文]
     
    Grouting using calcium phosphate compound (CPC) has been used for countermeasure for liquefaction in geotechnical engineering applications and it is an economical and environmental friendly technique that develops to form calcium carbonate precipitation throughout the soil, leading to an increase in soil strength. In the paper, our aim was to improve strength by adding CPC with CaCO3 (commercially found) and scallop shell (Naturally found) powder and exceed a maximum UCS of 100 kPa after 28 days of curing, which is the strength required as a countermeasure against soil liquefaction during earthquake. For that, initially Toyoura sand test pieces were cemented by CPC solutions only and cured up to 56 days and carried out unconfined compressive strength (UCS) test. Moreover, Toyoura sand test pieces were cemented by CPCs with CaCO3 (CC) powder and CPCs with scallop shell powder and cured and these specimens also analyzed with UCS tests. The UCS of the sand test pieces cemented by CPC with scallop shell powder and CC powder was higher than that of the test pieces with no added powders. In addition, a series of laboratory experiments were conducted, including pH concentration, scanning electron microscope (SEM) in order to observe the microscopic structure, density before and after curing etc. The results indicate that the density and the pH concentration of the sand test pieces cemented by CPC with scallop shell powder and CC powder were higher than that of the test pieces with no added powders.
  • Segmentation of multi-phase X-ray computed tomography images
    Masaji Kato, Manabu Takahashi, Satoru Kawasaki, Katsuhiko Kaneko
    Environmental Geotechnics 2 2 104 - 117 2014年03月 [査読有り][通常論文]
  • Electrokinetic properties of pasteurii and aquimarina bacteria
    Hamed A. Keykha, Bujang B. K. Huat, Afshin Asadi, Mohsen Zareian, Satoru Kawasaki
    Environmental Geotechnics 2 3 181 - 188 2014年03月 [査読有り][通常論文]
  • Sang Ho Cho, Mitsuhiro Yokota, Mayumi Ito, Satoru Kawasaki, Soo Bok Jeong, Byoung Kon Kim, Katsuhiko Kaneko
    MINERALS ENGINEERING 57 79 - 85 2014年03月 [査読有り][通常論文]
     
    Electrical disintegration is an effective liberation technique in mineral processing where the liberation ratio depends on the mineralogical properties of the mineral grains. However elucidation of the liberation behavior is difficult since the fragments after the electrical disintegration are fine and complex. This study applies electrical disintegration to cement paste samples with various dispersed mineral particles (calcite, quartz, albite, and pyrite) and the disintegrated products are observed with a micro-focus X-ray CT scanner. Current channels and crack extension behavior from the channels are identified by cross sectional CT and three dimensional reconstructed images. A classification of the crack patterns was carried out and compared with the results of liberation ratio measurements of the products. (C) 2014 Elsevier Ltd. All rights reserved.
  • Takashi Danjo, Satoru Kawasaki
    MATERIALS TRANSACTIONS 55 3 493 - 500 2014年03月 [査読有り][通常論文]
     
    Beachrock is a type of sedimentary deposit held together mainly by calcium carbonate cement in the tidal zone of sandy beaches in tropical and subtropical regions. Man-made beachrock has the potential to inhibit coastal erosion; considering this important application, we performed field investigations and laboratory tests to understand the formation mechanisms of beachrocks in Okinawa and Ishikawa, Japan. We performed a needle penetration test, microbial population count and urease activity test, and conducted elemental and mineral analyses. Our investigation showed that in Okinawa the evaporation of seawater and/or urease activity of the microorganisms may have resulted in precipitation of high Mg calcite, leading to the formation of beachrock. In Ishikawa, beachrock and sand were present near a spring with a relatively high concentration of Al3+. The mixing of spring water (pH 4.7) with seawater could have led to the precipitation of the Al- and Si-bearing cement that is consolidating the sand particles, leading to development of beachrock.
  • Ryosuke Kubo, Satoru Kawasaki, Koichi Suzuki, Shinji Yamaguchi, Toshiro Hata
    MATERIALS TRANSACTIONS 55 2 342 - 350 2014年02月 [査読有り][通常論文]
     
    This paper describes the knowledge obtained from a study of geophysical prospecting for beachrock. Previous studies on beachrock worldwide have been focused on the geochemistry. However, more knowledge of the chemical and physical properties is needed to elucidate the formation mechanism. In the present study, a direct current (DC) electrical survey and a surface seismic survey were conducted to detect the underground structure of the beachrock on Yagaji Island, Okinawa, Japan. This was a first attempt at conducting multiple geophysical surveys to investigate beachrock. In each survey, one survey line was set perpendicular to the seashore and two survey lines were set roughly parallel to the seashore. The results of each survey were observed in section of resistivity and seismic wave velocity. Furthermore, in order to estimate the effectiveness of the surveys, laboratory tests were conducted on the beachrock samples collected from the study site to measure the porosity, the resistivity, and the velocities of primary- (P-) waves and secondary- (S-) waves. There was a superior correlation between the sections and with the data on the study site. Hence, the features of the beachrock at the site are as follows: the resistivity is about 4-16 Omega m, the S-wave velocity is about 325 m/s, the thickness is about 1 m, and the thickness has a tendency to become greater toward the sea. One beachrock formation mechanism obtained by this study is close a currently accepted mechanism.
  • Takashi Danjo, Satoru Kawasaki
    Geotechnical and Geological Engineering 32 2 215 - 246 2014年 [査読有り][通常論文]
     
    Beachrocks are calcareous rocks that have been quite recently formed and are found in the intertidal zone on sandy beaches. The authors are developing an artificial rock with self-healing capabilities that can be used in coastal areas to repair the infrastructure of coastal walls. Because beachrocks are formed naturally on beaches, they merit study as a model for artificial rocks. We conducted a bibliographical study in order to gather information about the characteristics of beachrocks, which may aid in the manufacturing of artificial rocks. This study investigated their geographic distribution, formative periods, physical properties, and origins. The study found that over 90 % of beachrocks are found between the latitudes 40°N and the Tropic of Capricorn, and that their formative periods range from 26,000 years to just a few decades ago. We also learned that the cement component of beachrocks mainly consists of either calcium carbonate or silica. The dynamic characteristics of these components have been studied in only three papers, which note that their uniaxial compression strength ranges from as low as 6.0 to 42.0 MPa. Since very limited data are available on beachrocks in Japan where the artificial rock technology will first be deployed, there is a need for collecting additional data on their mechanical properties, elemental composition ratios, and mineral content. © 2013 Springer Science+Business Media Dordrecht.
  • Takashi Danjo, Satoru Kawasaki
    Materials Transactions 55 3 493 - 500 2014年 [査読有り][通常論文]
     
    Beachrock is a type of sedimentary deposit held together mainly by calcium carbonate cement in the tidal zone of sandy beaches in tropical and subtropical regions. Man-made beachrock has the potential to inhibit coastal erosion considering this important application, we performed field investigations and laboratory tests to understand the formation mechanisms of beachrocks in Okinawa and Ishikawa, Japan.We performed a needle penetration test, microbial population count and urease activity test, and conducted elemental and mineral analyses. Our investigation showed that in Okinawa the evaporation of seawater and/or urease activity of the microorganisms may have resulted in precipitation of high Mg calcite, leading to the formation of beachrock. In Ishikawa, beachrock and sand were present near a spring with a relatively high concentration of Al3+. The mixing of spring water (pH 4.7) with seawater could have led to the precipitation of the Al- and Si-bearing cement that is consolidating the sand particles, leading to development of beachrock. © 2014 The Japan Institute of Metals and Materials.
  • Soil reinforcement using calcium phosphate compounds
    Kawasaki, S, Akiyama, M
    Proceedings of International Conference on Georesources and Geological Engineering 412 - 421 2013年12月 [査読有り][招待有り]
  • S. Kawasaki, M. Akiyama
    SOILS AND FOUNDATIONS 53 6 966 - 976 2013年12月 [査読有り][通常論文]
     
    To improve the unconfined compressive strength (UCS) of a novel chemical grout composed of a calcium phosphate compound (CPC-Chem), we performed UCS tests and scanning electron microscopy (SEM) observations on sand test pieces cemented with CPC-Chem and four kinds of powders (tricalcium phosphate, TCP; magnesium phosphate. MgP, calcium carbonate, CC and magnesium carbonate. MgC) as seed crystals. The UCS of the CPC-Chem test pieces cemented with TCP and CC was significantly greater than that of the test pieces with no added powders. The UCS of the test pieces with TCP and CC additives exceeded the targeted value of 100 kPa and increased to a maximum of 261.4 kPa and 209.7 kPa for the test pieces with TCP and CC additives, respectively. Furthermore, the UCS of test pieces with 1 wt% or 5 wt% TCP and 1 wt% CC additives was maintained at a level exceeding 200 kPa for 168 days. SEM observations revealed net-like and three-dimensional structures in segments of test pieces cemented with 1 wt% or 5 wt % TCP and 1 wt% CC in CPC-Chem, which could have been the reason of the long-term stability of UCS (over 200 kPa for 168 days) observed in this study. These results suggest that the addition of TCP and CC significantly enhances the ground improvement afforded by CPC-Chem. (C) 2013 The Japanese Geotechnical Society. Production and hosting by Elsevier B.V. All rights reserved.
  • Geological structure of beachrock by geophysical exploration: applicayio to Yagaji Island in Okinawa, Japan
    Kubo, R, Kawasaki, S, Suzuki, K, Yamaguchi, S, Hata, T
    Proceedings of the 11th Society of Exploration Geophysics of Japan International Symposium Paper ID: 051  2013年11月 [査読有り][通常論文]
  • A study of the formation mechanism of beachrock in Okinawa, Japan: Toward making artificial rock
    Danjo, T, Kawasaki, S
    Proceedings of the Third International Conference on Geotechnique, Construction Materials and Environment (GEOMATE 2013) 101 - 106 2013年11月 [査読有り][通常論文]
  • Satoru Kawasaki, Masaru Akiyama
    MATERIALS TRANSACTIONS 54 11 2079 - 2084 2013年11月 [査読有り][通常論文]
     
    For the purpose of improving a novel grout composed of a calcium phosphate compound (CPC-Chem), we have conducted an unconfined compressive strength (UCS) test on samples cemented with CPC-Chem and tricalcium phosphate (TCP) powder. The UCS of these test samples was significantly larger than the UCS of the non-additive test samples. The UCS reached the targeted value of over 100 kPa, and after 28 days of curing, reached a maximum of 261.4 kPa. Additionally, the pH of the samples cemented with CPC-Chem and TCP powder was weakly acidic. These results suggest that the novel geotechnical method using a combination of CPC-Chem and TCP powder has the potential to be used as a non-contaminating and recyclable application, as a biogrout that uses microbial activity and for ground improvement because it satisfies the strength requirements for practical use.
  • 鈴木浩一, 川﨑 了, 久保良介, 山口伸治, 畠 俊郎
    物理探査 66 4 277 - 285 社団法人 物理探査学会 2013年10月 [査読有り][通常論文]
     
    沿岸域で適用可能な自己修復能力を持つ人工岩盤に関する研究は,環境に負荷を与えず低コストで海岸堤防を建設する上で重要と考えられ,自然材料(微生物,砂,貝殻,サンゴ片,海藻など)を用いて厳しい気象条件に耐えうる強度の人工岩盤を比較的短期間で形成させることを目標としている。その一つのモデルとして,熱帯・亜熱帯地域のサンゴ礁沿岸域に存在するビーチロックが着目されているが,その地下構造を明らかにした調査事例はほとんどない。そこで,沖縄県内に数多く分布が確認されているビーチロックの地下構造を地表面から非破壊で明らかにすることを目的に,電気探査法および表面波探査法を行った。また,ビーチロック試料を用いた室内試験によりその物理特性を計測した。その結果,ビーチロックはその下部にある未固結の砂層より明らかに比抵抗と弾性波速度が大きく,その厚さは最大1m程度で海側に近いほど厚さは増加する傾向があることが分かった。
  • J. Kodama, T. Miyamoto, S. Kawasaki, Y. Fujii, K. Kaneko, P. Hagan
    INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES 63 1 - 11 2013年10月 [査読有り][通常論文]
     
    A method to evaluate regional stress state and Young's modulus by analyzing the mining-induced deformation of ground is proposed. The effect of changes in regional strain state due to tectonic plate motion can be accounted for using the proposed method. Mining-induced deformation can manifest itself as changes in ground surface geometry resulting from mining activity. There are three underlying factors that can contribute to the deformation, these being: displacement induced by the effect of gravity; displacement induced by the effect of horizontal regional strain; and, incremental change in the horizontal regional strain. Both regional strain and Young's modulus can be simultaneously estimated, because the displacement induced by the regional strain is independent of the Young's modulus and the displacement induced by the gravity is inversely proportional to the Young's modulus. The relative displacement arising from the mining excavation at the Torigatayama limestone mine in Japan has been measured by GPS. Both the regional stress state and Young's modulus were estimated by back analysis of the relative displacement using a 3-D finite element method. It was shown that back analysis based on changes in distance between the measurement points provides a more reliable estimation than that could be achieved based on the direct relative displacement. (C) 2013 Elsevier Ltd. All rights reserved.
  • Kubo, R, Kawasaki, S, Suzuki, K, Yamaguchi, S, Hata, T
    Proceedings of EUROCK 2013 - The ISRM International Symposium, Rock Mechanics for Resources, Energy and Environment 299 - 304 2013年09月 [査読有り][通常論文]
  • Danjo, T, Kawasaki, S
    International Journal of GEOMATE 5 1 634 - 639 The GEOMATE International Society 2013年09月 [査読有り][通常論文]
  • 檀上 尭, 川﨑 了
    Journal of MMIJ 129 7 520 - 528 The Mining and Materials Processing Institute of Japan 2013年07月 [査読有り][通常論文]
     
    Beachrocks are coastal deposits cemented mainly by calcium carbonate cement; these deposits are found in the tidal zone of sandy beaches in tropical and subtropical regions. Manmade beachrocks have the potential to inhibit coastal erosions; considering this important application, we performed field investigations and laboratory tests to understand the formation mechanisms of beachrocks in Okinawa and Ishikawa, Japan. We performed a needle penetration test, determination of viable count, elemental analyses and mineral analysis. Our investigation of the formation mechanisms of the beachrocks showed that in Okinawa, the evaporation of seawater and/or urease activity of the microorganisms may have resulted in the precipitation of high Mg calcite (HMC), leading to the formation of beachrocks. On the other hand, in Ishikawa, beachrocks and sand were present near a spring. Here, the pH value of the spring was in the range 4.7 and it has a higher concentration of Al3+. The mixing of spring water with seawater could have led to the precipitation of the cement containing Al and Si between sand particles and, thus resulting in the formation of the beachrock. Therefore, we have interpreted the formation mechanisms of beachrocks.
  • 鈴木 浩一, 川崎 了, 久保 良介, 山口 伸治, 畠 俊郎
    物理探査学会学術講演会講演論文集 = Proceeding of the SEGJ Conference 128 150 - 153 物理探査学会 2013年06月13日 [査読無し][通常論文]
  • Kawasaki, S, Akiyama, M
    International Journal of GEOMATE 4 1 429 - 435 The GEOMATE International Society 2013年03月 [査読有り][通常論文]
  • Masaji Kato, Manabu Takahashi, Satoru Kawasaki, Toshifumi Mukunoki, Katsuhiko Kaneko
    MATERIALS TRANSACTIONS 54 9 1678 - 1685 2013年 [査読有り][通常論文]
     
    The physical properties of two-phase materials depend on their internal structure. Therefore, segmentation of the structure of such materials is important in material sciences. In this study, we used a maximum likelihood thresholding method that considered the partial volume effect -i.e., the effect of mixels (mixed pixels)- to calculate the porosities of packed glass beads and the Berea sandstone using microfocus X-ray computed tomography (CT) images. We also examined the effects of scanning conditions on the segmentation results and assessed the porosity of possible packing structures of the glass beads to be segmented to be 33-37% based on histogram data. Moreover, we evaluated the porosity of the Berea sandstone to be 18%. Then, we examined variation in the porosity of biogrouted packing of glass beads using a microfocus X-ray CT scanner and histogram-based image analysis with the same thresholding method. Our results indicated that the ratio of grouted to ungrouted geomaterial porosities was 0.98, whereas the value estimated by measuring changes in the concentration of calcium ions was 0.98-0.99. Thus, we have confirmed that the proposed method can evaluate small changes in porosity with high accuracy.
  • ビーチロックの強度増加に及ぼす影響因子に関する考察
    檀上 尭, 川﨑 了
    第13回岩の力学国内シンポジウム&第6回日韓ジョイントシンポジウム講演論文集 617 - 622 2013年01月 [査読無し][通常論文]
  • Unique grouting material composed of calcium phosphate compounds
    Kawasaki, S, Akiyama, M
    Proceedings of the Second International Conference on Geotechnique, Construction Materials and Environment (GEOMATE 2012) 40 - 46 2012年11月 [査読無し][招待有り]
  • Electrophoresis of bacteria and electro-biogrouting
    Hamed A. Keykha, Bujang B. K. Huat, Afshin Asadi, S. Kawasaki
    Proceedings of the Second International Conference on Geotechnique, Construction Materials and Environment (GEOMATE 2012) 230 - 233 2012年11月 [査読無し][通常論文]
  • 檀上 尭, 川﨑 了
    応用地質 53 4 191 - 200 一般社団法人 日本応用地質学会 2012年10月 [査読有り][通常論文]
     
    筆者らは,国内外の文献において報告例が少ないビーチロックの物理・力学特性を把握し,さらに一軸圧縮強度と各種特性の相関を検討することを目的として,原位置試験および室内試験を実施した.その結果,ビーチロックの湿潤状態における一軸圧縮強度は,調査地点A,M,Gでそれぞれ平均値11.14 MPa,標準偏差4.50 MPa(サンプル数6本),平均値19.91 MPa,標準偏差7.68 MPa(サンプル数3本),平均値42.23 MPa,標準偏差12.64 MPa(サンプル数6本)であった.また,ビーチロックは時間の経過に伴って,含水比が低下し,密度および一軸圧縮強度が増加しており,一軸圧縮強度qu(MPa)と形成年代t(y Cal BP)の間には,qu=0.00000654 t2+0.0101t(相関係数は0.825)なる傾向がみられた.
  • Masaru Akiyama, Satoru Kawasaki
    ECOLOGICAL ENGINEERING 47 264 - 267 2012年10月 [査読有り][通常論文]
     
    We added calcium carbonate (CC) powder to a novel grout made from calcium phosphate compound (CPC-chem) to increase the ground strength improvement afforded by CPC-chem. We conducted the unconfined compressive strength (UCS) test and scanning electron microscopy (SEM) observation on test pieces cemented with CPC-chem and CC powder. The UCS of test pieces cemented with CPC-chem and CC powder was significantly higher than that of test pieces cemented without CC powder, and it reached a maximum of 209.7 kPa. The UCS of test pieces cemented with CC powder and deionized water was 12.5 kPa, which was similar to that of test pieces cemented with deionized water only (10 kPa). SEM observation revealed mesh-like and three-dimensional structures in the segment of the test piece cemented with CPC-chem and 1 wt% of CC, which showed UCS of over 200 kPa and the minimum axial strain rate among all cases in this study. These results suggest that the addition of CC powder significantly enhances the ground improvement afforded by CPC-chem. (c) 2012 Elsevier B.V. All rights reserved.
  • 秋山 克, 川﨑 了
    地盤工学ジャーナル 7 3 491 - 501 2012年09月 [査読有り][通常論文]
  • Segmentation of multi-phase X-ray computed tomography images of porous materials considering partial volume effect
    Kato, M, Yamanaka, H, Takahashi, M, Kawasaki, S, Kaneko, K
    Proceedings of the 2012 World Congress on Advances in Civil, Environmental, and Materials Research (ACEM' 12) 278 - 294 2012年08月 [査読無し][通常論文]
  • 檀上 尭, 川﨑 了
    応用地質 53 3 129 - 141 日本応用地質学会 2012年08月 [査読有り][通常論文]
  • Properties of beachrocks in Okinawa and Ishikawa, Japan
    Danjo, T, Kawasaki, S
    Proceedings of the 34th International Geological Congress 1521  2012年08月 [査読無し][通常論文]
  • Masaru Akiyama, Satoru Kawasaki
    ENGINEERING GEOLOGY 137 29 - 39 2012年06月 [査読有り][通常論文]
     
    To evaluate the potential utility of a new calcium-phosphate-compound (CPC)-based biogrout (CPC biogrout), we conducted unconfined compressive strength (UCS) tests and scanning electron microscope (SEM) observations of sand test pieces cemented with CPC biogrout. The CPC biogrout was produced using (1) soil extracts that contained microorganisms derived from one of two soils, which had different pH values, and (2) one of three amino acids or urea as a pH-increasing reactant. A temporal increase in pH was observed in slightly acidic soil by the addition of ammonia sources. On the other hand, there was no significant increase in pH in slightly alkaline soil except for that due to urea. In most cases, the UCS of the test pieces cemented with CPC biogrout produced using soil extracts from acidic soil along with an ammonia source was higher than that of the test pieces cemented with CPC biogrout produced without the addition of ammonia sources. SEM observation of test pieces with UCS of over 50 kPa showed the presence of whisker-like CPC crystals. These results suggest that CPC biogrout affords sufficient strength as a countermeasure for soil liquefaction and that amino acids can be used as new pH-increasing reactants for CPC biogrout In addition, they suggest that either CPC biogrout or CPC chemical grout alone, or a combination of the two grouts, can be used depending on the various properties of grounds and soils. (C) 2012 Elsevier B.V. All rights reserved.
  • Hamed A. Keykha, Bujang B. K. Huat, Afshin Asadi, Satoru Kawasaki
    INTERNATIONAL JOURNAL OF ELECTROCHEMICAL SCIENCE 7 2 1196 - 1204 2012年02月 [査読有り][通常論文]
     
    Biogrouting is a new method to stabilize sandy soils through precipitation of CaCO3 between grains. This process decreases the permeability about 98% and increases the soil strength up to 12Mpa. It is created by bacterium Bacillus Pasteurii and enzyme urease that hydrolyze urea to carbonic dioxide and ammonia. A major problem in biogrouting is the distribution of bacteria injected into the soils. The bacteria grows more in at 30-37 degrees C and pH 9.2, but cannot be distributed homogeneously in soil through biogrouting technique. It depends on the grain size, mineralogy, and properties of the pore fluid. The electrokinetic (EK) technique transports charged particles and fluid in porous media. This technology moves a wide range of particles, including ions, metals and organics. The Bacillus bacteria are rod-shaped bacterium with many negative charges in the surface. The electrokinetic can probably transport bacteria towards the cathode in an experimental cell and can distribute them uniformly in porous media of soils for fertile biogrouting. It explains a wide range of diffusion of bacteria influenced electric current. However, basic environment electrokinentic phenomena can probably affect bacterial membrane composition and metabolic activity, but it also justifies an increase of soil pH and can provide a positive effect on microbial activity and bacterial community of Bacillus Pasteurii. Furthermore distribution of the urease enzyme could be possible in electrokinetic environment since the urease enzyme has a negative charge at pH of more than 5.5. The urease enzyme is a negatively charged at a pH more than 5.5 which is able to move and diffuse in electrical environment.
  • 畠 俊郎, 佐藤厚子, 川﨑 了, 阿部廣史
    土木学会論文集C(地圏工学) 68 1 31 - 40 2012年 [査読有り][通常論文]
  • ビーチロックの物理・力学特性
    檀上 尭, 川﨑 了
    第41回岩盤力学に関するシンポジウム講演集 89 - 94 2012年 [査読無し][通常論文]
  • Masaru Akiyama, Satoru Kawasaki
    ENGINEERING GEOLOGY 125 119 - 128 2012年01月 [査読有り][通常論文]
     
    Calcium phosphate compounds (CPCs) have unique physicochemical properties. As grout material, they afford many advantages such as adequate physical strength, self-setting property, pH dependence of precipitation, non-toxicity, and recyclability. To apply CPCs to the permeability control and reinforcement of ground soil and rock, we explored suitable conditions for in vitro CPC precipitation, conducted unconfined compressive strength (UCS) tests of Toyoura sand test pieces cemented by CPC, and carried out observations and elemental analysis of precipitated CPC crystals. Two kinds of phosphate stock solution and two kinds of calcium stock solution were used to prepare the reaction mixtures, and CPC precipitation was detected in all reaction mixtures. The volume of CPC precipitation in the reaction mixture increased as the pH rose from strongly acidic to around neutral. The UCS of Toyoura sand test pieces cemented by 1.5 M diammonium phosphate and 0.75 M calcium acetate tended to increase with time, reaching a maximum of 63.5 kPa after 14 days of curing. Conversely, the UCS of test pieces cemented by using calcium nitrate was below 20 kPa and showed no significant increase in strength. CPC precipitation with calcium nitrate induced the formation of plate-like crystals, whereas that with calcium acetate induced whisker-like crystals. Elemental analysis of the cemented test pieces showed that the distributions of phosphorus and calcium were similar. The results indicate the practical feasibility of using novel CPC grouts as chemical grouts because of their self-setting property, and as biogrouts because of their crystal structure and pH dependence of precipitation. (C) 2011 Elsevier B.V. All rights reserved.
  • M. Akiyama, S. Kawasaki
    HARMONISING ROCK ENGINEERING AND THE ENVIRONMENT 1449 - 1452 2012年 [査読無し][通常論文]
     
    To develop novel rock grout materials using Calcium Phosphate Compounds (CPC), we explored suitable conditions for CPC precipitation in vitro, conducted Unconfined Compressive Strength (UCS) tests of sand test pieces cemented by CPC, and observed precipitated CPC crystals by scanning electron microscopy. The volume of CPC precipitation in the reaction mixture increased with pH, rising from weakly acidic to around neutrality. Sand test pieces cemented with a reaction mixture containing 1.5M diammonium phosphate and 0.75M calcium acetate showed a tendency for the UCS to increase with time, reaching a maximum of 87.6 kPa. CPC precipitation via calcium nitrate treatment induced the formation of platelike crystals, whereas that via calcium acetate treatment induced whisker-like crystals. The results indicate the fundamental feasibility of novel CPC rock grouts including chemical grouts using the self-setting property of CPC, and biogrouts using the pH dependence of the precipitation and crystal structure of CPC.
  • T. Danjo, S. Kawasaki
    HARMONISING ROCK ENGINEERING AND THE ENVIRONMENT 949 - 952 2012年 [査読無し][通常論文]
     
    Beachrock is a coastal deposit with calcium carbonate and/or silica cement in the tidal zone of sandy beaches. Considering the application of man-made beachrock to preserve submerged-looking islands, we performed a literature survey and a field investigation to understand essential beachrock characteristics. We found that 90% of beachrocks worldwide were distributed within latitude of approximately 40 degrees north of the southern circle. It was also found that beachrock formed from several decades ago to around 7350 years ago. Furthermore, the main elements in beachrock worldwide differed. The beachrock in Okinawa, Japan mainly consisted of Ca and C. The unconfined compression strength, q(u), was from 5.63 to 57.80MPa. The relation between qu and formative age, t, was q(u) = 0.0141t. From these results, we obtained a wealth of data to build man-made beachrock.
  • 微生物機能を利用した地盤改良技術
    川﨑 了
    地盤と建設 29 1 11 - 18 2011年 [査読有り][招待有り]
  • Relationship between crystal features of calcium phosphate compounds in chemical grout and unconfined compression strength of grouted sand
    Aoi, S, Kawasaki, S, Akiyama, M
    Proceedings of International Conference "Environmental Geosciences and Engineering Survey for Territory Protection and Population Safety" 504 - 508 2011年 [査読無し][通常論文]
  • 秋山 克, 川﨑 了
    地盤工学ジャーナル 6 2 341 - 350 2011年 [査読有り][通常論文]
  • 山中裕史, 川﨑 了, 加藤昌治, 椋木俊文, 金子勝比古
    地盤工学ジャーナル 6 2 273 - 284 2011年 [査読有り][通常論文]
  • 稲垣由紀子, 塚本将康, 森 啓年, 中島 進, 佐々木哲也, 川﨑 了
    地盤工学ジャーナル 6 2 157 - 167 2011年 [査読有り][通常論文]
  • 椋木俊文, 川﨑 了, 下屋敷覚弘, 吉永智昭
    地盤工学ジャーナル 5 4 545 - 553 2010年 [査読有り][通常論文]
  • 寺島 麗, 島田俊介, 小山忠雄, 川﨑 了
    地盤工学ジャーナル 5 3 425 - 435 2010年 [査読有り][通常論文]
  • E. Nishiyama, T. Miyamoto, J. Kodama, S. Kawasaki, K. Kaneko, Y. Yoshida
    ROCK MECHANICS IN CIVIL AND ENVIRONMENTAL ENGINEERING 681 - 684 2010年 [査読無し][通常論文]
     
    A method to evaluate regional stress state and Young's modulus by analyzing mining induced deformation of ground is proposed. Mining induced deformation is interpreted as the deformation due to the geometrical change of ground surface caused by mine activity and it is classified into two types, i.e., the displacement increment induced by the gravity and that by the horizontal regional strain. It is pointed out that both regional strain and Young's modulus can be estimated by analyzing the mining induced deformation, because the displacement induced by the regional strain is independent of the Young's modulus and the displacement induced by the gravity is in inversely proportional to the Young's modulus. The relative displacement arising from mine excavation in Torigatayama limestone mine, Japan have been measured by GPS. Both the stress state and Young's modulus of the regional field including the limestone mine were estimated by back-analysis using three dimensional finite element method. It is shown that the maximum principal direction of the regional stress is almost NE-SW and Young's modulus of the ground is between 3 and 6 GPa.
  • 川﨑 了, 小潟 暁, 広吉直樹, 恒川昌美, 金子勝比古, 寺島 麗
    応用地質 51 1 10 - 18 一般社団法人 日本応用地質学会 2010年 [査読有り][通常論文]
     
    筆者らは, 土や岩の代表的なセメント物質である炭酸カルシウムまたはシリカを主成分とし, 微生物の代謝活動により土や岩の間隙や岩の割れ目を自然に閉塞させる新たな概念に基づくグラウト, すなわち, バイオグラウトを開発するための基礎的な研究を実施中である. 本論文では, 炭酸カルシウムを用いたバイオグラウト, すなわち, 炭酸カルシウム法に関して検討を実施した結果について報告する. 具体的には, 日本各地より採取した自然の土壌中に生息する微生物を用いて試験管による炭酸カルシウムの析出試験を行い, 試験時における温度の違いが炭酸カルシウム析出に与える影響について調査した. その結果, 温度5~35℃の低~中温域において, 土壌微生物により炭酸カルシウムが試験管内に析出することが示唆された. 一方, 試験に用いた土壌微生物の菌数測定および遺伝子解析を実施し, 試験前後の土壌中に含まれる微生物相の変化に関して, 生菌数, 最も出現頻度の高い菌の菌数およびその帰属分類群を用いることにより比較を行った. その結果, それらは主にPenicillium属およびAspergillus属の菌類であり, 有機栄養源を活発に代謝することにより菌数が増加したものと推定された.
  • 椋木俊文, 吉永智昭, 川﨑 了
    地盤工学ジャーナル 5 1 69 - 80 2010年 [査読有り][通常論文]
  • Kobayashi, Y, Kawasaki, S, Kato, M, Mukunoki, T, Kaneko, K
    Proceedings of the 3rd International Workshop on X-Ray CT for Geomaterials: GeoX 2010 287 - 294 2010年 [査読有り][通常論文]
  • X線CT法によるバイオグラウト処理された供試体内部の間隙率評価
    小林優矢, 川﨑 了, 加藤昌治, 椋木俊文, 金子勝比古
    第39回岩盤力学に関するシンポジウム講演集 213 - 217 2010年 [査読無し][通常論文]
  • 小林優矢, 川﨑 了, 加藤昌治, 椋木俊文, 金子勝比古
    Journal of the Mining and Materials Processing Institute of Japan 125 10/11 540 - 546 The Mining and Materials Processing Institute of Japan 2009年 [査読有り][通常論文]
     
    This study considers a method for evaluation of porosity of biogrouted geomaterials. First, we visualized the internal structures of the specimens by using micro-focused X-ray CT scanner. We tested Souma sand, gum tips, plastic pellets, steel balls and glass beads as geomaterial to find suitable geomaterials for evaluation of porosity: geomaterials whose CT-number histogram was bimodal. The results clarified that one of the geomaterials, glass beads whose particle size was 0.50-0.71mm, was suitable for evaluation of porosity. Second, we calculated the porosity of the glass beads by using a method for evaluation of porosity based on a maximum likelihood thresholding method considering the effect of mixels. The result showed that the ratio of the porosity of grouted geomaterial to that of ungrouted geomaterial was 0.98 to 0.99. On the other hand, the value estimated by the measurement of changes in concentration of calcium ion was 0.98. Thus, both values closely agreed. Therefore, this study clarifies that the method enables us to evaluate small change in porosity with great accuracy.
  • Temperature dependence of calcium carbonate precipitation for biogrout
    Ogata, S, Kawasaki, S, Hiroyoshi, N, Tsunekawa, M, Kaneko, K, Terajima, R
    Proceedings of the Regional Symposium of the International Society for Rock Mechanics, EUROCK 2009 339 - 344 2009年 [査読無し][通常論文]
  • 清田佳奈, 村上 章, 川﨑 了
    応用地質 50 2 70 - 78 一般社団法人日本応用地質学会 2009年 [査読有り][通常論文]
     
    農業用ため池に堆積する土砂(以後,「底泥」とする)は水質改善や貯水効率維持のために浚渫されるが,高含水比であるのでそのまま運搬することができず,処理も難しい.本研究では,環境に配慮して底泥を処理し再利用する手段を新たに開発するため,シリカコロイド溶液と微生物代謝を利用したバイオ固化処理の可能性を確認することを目的として,ため池底泥を対象に室内試験を実施した.具体的には,底泥を対象土とし,シリカグラウト溶液,イースト菌,グルコースを用いた固化材(以後,「バイオ固化材」と称する)の配合比の検討を行い,シリカグラウト溶液5ml,イースト菌1.25g,グルコース0.3gのバイオ固化処理により処理可能な底泥量が5gであることを把握した後,底泥中の微生物や有機栄養源がバイオ固化処理に利用できることを確認した.次に,液性限界・塑性限界試験を行い,バイオ固化処理により塑性指数が低下することを明らかにした.さらに,フォールコーン試験を行い,バイオ固化処理の前後における貫入量を比較することで,同一の含水比状態ではバイオ固化処理により底泥が硬化することが明らかとなった.
  • Effect of temperature on rate of CaCO3 precipitation for biogrouting process
    Ogata, S, Kawasaki, S, Hiroyoshi, N, Tsunekawa, M, Kaneko, K, Terajima, R
    Proceedings of 3rd International Workshop and Conference on Earth Resources Technology 12 - 17 2009年 [査読有り][通常論文]
  • 寺島 麗, 島田俊介, 小山忠雄, 川﨑 了
    土木学会論文集C 65 1 120 - 130 2009年 [査読有り][通常論文]
  • 微生物代謝を利用したグラウトにおける炭酸カルシウム析出の温度依存性
    小潟 暁, 川﨑 了, 広吉直樹, 恒川昌美, 金子勝比古, 寺島 麗
    第38回岩盤力学に関するシンポジウム講演論文集 120 - 124 2009年 [査読無し][通常論文]
  • Effect of temperature on precipitation of calcium carbonate for biogrout
    Ogata, S, Kawasaki, S, Hiroyoshi, N, Tsunekawa, M, Kaneko, K, Terajima, R
    Proceedings of the Korean Rock Mechanics Symposium 2008 -International Cooperation and Rock Engineering for Development of Mineral Resources and Infrastructures- 271 - 277 2008年 [査読無し][通常論文]
  • 西山えるむ, 宮本高充, 児玉淳一, 川﨑 了, 金子勝比古
    Journal of the Mining and Materials Processing Institute of Japan 124 9 570 - 575 The Mining and Materials Processing Institute of Japan 2008年 [査読有り][通常論文]
     
    A method to evaluate the regional stresses and the Young's modulus by analyzing mining induced deformation of the ground is proposed.
    Mining induced deformation is interpreted as the deformation due to the geometrical change of the ground surface caused by mine activity and it is classified in two types, i.e., the displacement increment induced by gravity and that by the horizontal regional strain. It is pointed out that both the regional strain and Young's modulus can be estimated by analyzing the mining induced deformation, because the displacement induced by the regional strain is independent of the Young's modulus and the displacement induced by the gravity is inversely proportional to the Young's modulus.
    The relative displacement due to mine excavation in Torigatayama mine were measured by GPS (Global Positioning System) and the regional stress state and Young's modulus were estimated by a back-analysis using three dimensional finite element method. It is shown that the maximum principal direction of regional stresses is almost NE-SW and Young's modulus of the ground is 3 to 6GPa in the present field.
  • 鳥形山鉱山における広域応力と地盤ヤング率の検討
    西山えるむ, 宮本高充, 児玉淳一, 川﨑 了, 金子勝比古
    第12回岩の力学国内シンポジウム講演論文集 281 - 287 2008年 [査読無し][通常論文]
  • 微生物代謝を用いたシリカ系注入材バイオグラウトの開発
    寺島 麗, 島田俊介, 小山忠雄, 市川智史, 川﨑 了, 広吉直樹
    第12回岩の力学国内シンポジウム講演論文集 239 - 244 2008年 [査読無し][通常論文]
  • バイオグラウトにおける炭酸カルシウムの析出に及ぼす温度の影響
    川﨑 了, 小潟 暁, 広吉直樹, 恒川昌美, 金子勝比古, 寺島 麗
    地盤工学会北海道支部技術報告集 48 27 - 30 2008年 [査読無し][通常論文]
  • 川崎 了, 趙 祥鎬, 金子 勝比古
    応用地質 48 4 162 - 169 一般社団法人日本応用地質学会 2007年 [査読無し][通常論文]
     
    一般に,岩石は自然の浸食や人工的な掘削などによって地表にさらされると酸化され,結果的に岩石の強度が低下する.このような風化作用を受けた岩石の風化層厚を現場において非破壊,簡易,定量的に推定することができれば,応用地質学および地盤工学などの分野において有効と考えられる.筆者らは,ボーリングコアなどの岩石あるいは露頭している岩盤の比較的薄い表層の風化層厚を非破壊,簡易,定量的に推定する手法を新たに開発するために,風化した岩石を模擬した4種類の人工風化岩を作製し,それらを用いたエコーチップ反発硬度試験を行った.そして,とくに人工風化岩の風化層厚および風化層と未風化層の反発硬度の比に注目し,実験的な検討を実施した.本論では,最初に岩石あるいは岩盤の表層における風化層厚を評価するための人工風化岩モデルについて説明する.次に,人工風化岩の風化層の作製方法および作製された風化層の均質性に関して検討した結果について述べる.最後に,人工風化岩の反発硬度と人工風化岩の風化層および未風化層の反発硬度を用いて,人工風化岩の風化層厚を非破壊,簡易,定量的に推定することができる新たな一手法について提案する.
  • 川﨑 了, 趙 祥鎬, 金子勝比古
    応用地質 48 4 162 - 169 一般社団法人日本応用地質学会 2007年 [査読有り][通常論文]
     
    一般に,岩石は自然の浸食や人工的な掘削などによって地表にさらされると酸化され,結果的に岩石の強度が低下する.このような風化作用を受けた岩石の風化層厚を現場において非破壊,簡易,定量的に推定することができれば,応用地質学および地盤工学などの分野において有効と考えられる.筆者らは,ボーリングコアなどの岩石あるいは露頭している岩盤の比較的薄い表層の風化層厚を非破壊,簡易,定量的に推定する手法を新たに開発するために,風化した岩石を模擬した4種類の人工風化岩を作製し,それらを用いたエコーチップ反発硬度試験を行った.そして,とくに人工風化岩の風化層厚および風化層と未風化層の反発硬度の比に注目し,実験的な検討を実施した.本論では,最初に岩石あるいは岩盤の表層における風化層厚を評価するための人工風化岩モデルについて説明する.次に,人工風化岩の風化層の作製方法および作製された風化層の均質性に関して検討した結果について述べる.最後に,人工風化岩の反発硬度と人工風化岩の風化層および未風化層の反発硬度を用いて,人工風化岩の風化層厚を非破壊,簡易,定量的に推定することができる新たな一手法について提案する.
  • 柏谷公希, 川﨑 了, 金子勝比古, 米田哲朗
    応用地質 48 2 97 - 102 一般社団法人日本応用地質学会 2007年 [査読有り][通常論文]
     
    切土によって露出した新第三系中新統能取層泥質岩に一様でない盤膨れが発生した素因を,盤膨れの大きな箇所と小さな箇所のボーリングコアから採取した試料の鉱物組成,化学組成および岩石組織から考察した.試料の鉱物組成と化学組成に明確な差は認められないが,盤膨れの大きな箇所の試料は盤膨れの小さな箇所の試料よりも構成粒子が粗粒で,基質部へ蛍光剤入り樹脂が含浸しやすい.今回の盤膨れは,切土による露出で劣化した泥質岩が水の作用を受け,スメクタイトの膨潤などにより体積増加することで発生したとすると,粒度分布が異なることで生じた不連続構造の差異が盤膨れの大きさに影響を及ぼし,一様でない盤膨れを生じさせたと考えられる.
  • 川﨑 了, 村尾彰了, 広吉直樹, 恒川昌美, 金子勝比古
    応用地質 47 1 2 - 12 一般社団法人日本応用地質学会 2006年 [査読有り][通常論文]
     
    通常土壌には,1gあたり10^7〜10^9の微生物が含まれている.この非常に多くの微生物を,土や岩を対象とする工学の中でもとくに力学分野において利用することができれば,地球環境に配慮した新たな技術が開発されるものと期待される.筆者らは,土や岩の代表的なセメント物質の1つである炭酸カルシウムを主成分とし,微生物の代謝活動により土や岩の間隙や岩の割れ目を自然に閉塞させる新たな概念に基づくブラウト,すなわち,バイオグラウトを開発するための基礎的な室内試験を実施した.具体的には,市販のイースト菌および自然の土壌中に生息する微生物を用いて試験管による炭酸カルシウムの析出試験を行い,試験時の諸条件である温度,有機栄養源,緩衝溶液が炭酸カルシウムの析出に与える影響について検討した.また,バイオグラウトによる砂および粘土の透水特性の改良試験を実施し,バイオグラウト処理により両者の透水係数が処理前に比べて約1桁低下することを確認した.解決すべき残された課題は少なくないが,得られた試験結果より土壌微生物の代謝活動を利用したバイオグラウトによる地盤の物性改良およびバイオグラウトの開発に関して明るい見通しが得られた.
  • 微生物代謝により固化する新しいグラウトに関する基礎的検討
    村尾彰了, 川﨑 了, 広吉直樹, 恒川昌美, 金子勝比古
    第34回岩盤力学に関するシンポジウム講演論文集 417 - 422 2005年 [査読無し][通常論文]
  • F Shiraki, S Kawasaki, K Kaneko
    Contribution of Rock Mechanics to the New Century, Vols 1 and 2 899 - 902 2004年 [査読無し][通常論文]
     
    Relationships between optical and mechanical properties of rocks are discussed by paying attention to brightness and brightness difference of rocks with change of water content. In order to investigate effect of water content on optical and mechanical properties of several rocks, a series of laboratory test was conducted. The obtained results show that brightness and brightness difference could be one of the promising properties of rocks for estimating mechanical properties of rocks in a nondestructive manner.
  • 乾燥による岩石の物理的性質の変化に関する室内試験
    白木文香, 川﨑 了, 金子勝比古
    第33回岩盤力学に関するシンポジウム講演論文集 283 - 288 2004年 [査読無し][通常論文]
  • Estimation method for weathering thickness of man-made weathering rocks by using the Equotip hardness tester
    Kawasaki, S, Kaneko, K
    Proceedings of the ISRM Regional Symposium EUROCK 2004 and 53rd Geomechanics Colloquy 491 - 494 2004年 [査読無し][通常論文]
  • Influence of the rock mass inhomogeneity caused by layer geometry on the regional stress field
    Cho, S.H, Nakamura, K, Kawasaki, S, Yang, H.S, Sato, M, Nakama, S, Kaneko, K
    Tunnel and Underground Space, Journal of Korean Society for Rock Mechanics 14 2 142 - 153 2004年 [査読有り][通常論文]
  • 川崎 了, 白木 文香, 金子 勝比古
    地盤工学研究発表会 発表講演集 39 561 - 562 公益社団法人 地盤工学会 2004年 
    一般に,岩石の物理的性質は水分の影響を受け,その影響は硬岩よりも特に空隙が比較的大きい軟岩において著しいことが知られている。そこで,初期状態として含水飽和している岩石を乾燥させた際に見られる色および物理的性質の変化に着目し,岩石を乾燥させる前後において色および種々の物理的性質の測定を実施した。本報告では,岩石の色および物理的性質の中でも特にP波速度,反発硬度,密度などの測定を非破壊で実施した室内試験および試験結果の概要について述べた後に,(1)物理的性質間の相関関係,(2)明度差に着目した物理的性質の相関関係,などについて検討した結果を示す。
  • 分光測色計を用いた鉱物および岩石の色測定
    千引春菜, 川﨑 了, 金子勝比古
    第32回岩盤力学に関するシンポジウム講演論文集 323 - 328 2003年 [査読無し][通常論文]
  • S Kawasaki, K Nakamura, T Sato, S Nakama, K Kaneko
    ROCK STRESS 419 - 424 2003年 [査読無し][通常論文]
     
    A method for estimating the global stress field from the local stress field evaluated by the field initial stress measurement is discussed. As for numerical analysis of rock stress measurement, few research examples quantitatively evaluate inhomogeneity of the three dimensional initial stress fields in rock masses. In order to grasp the effect of inhomogeneity of rock masses, a homogeneous rock model and an inhomogeneous rock model including different strata were made and the global stress fields were estimated. Furthermore, the method of back analysis of global strains was investigated by using plural stress measuring points in the region specified. As a result of these analyses, it was found that analyses of stress states in deep rock masses required consideration of structures and mechanical properties of each stratum.
  • 人工風化岩を用いた簡易反発硬度試験
    阿部右吾, 川﨑 了, 金子勝比古
    第32回岩盤力学に関するシンポジウム講演論文集 329 - 334 2003年 [査読無し][通常論文]
  • S Kawasaki, K Kaneko, Y Obara, N Nakamura, R Tsukayama
    FIELD MEASUREMENTS IN GEOMECHANICS 513 - 518 2003年 [査読無し][通常論文]
     
    Using an earthmover as a loading source, an estimation method of elastic constants of rock masses is discussed. For regional rock masses, it is obvious that suitable large loads are required for field measurements of rock mass deformation. The present in-situ loading tests have, however, the limits of improving and scaling up of machinery and tools because of mechanical structure and/or economy of loading apparatus. It is, therefore, necessary to develop another different methodology from usual. Provided that an earthmover; which is generally used in a quarry, can be used as the weight of loading, loading tests of rock masses can be carried out without special and additional loading equipment. In anticipation of very small,deformation of the regional rock masses, deformation measurements with high accuracy are demanded. Consequently, the authors tried to solve this problem, by using a high-resolution tilt meter.
  • 谷本親伯, 鈴木淳也, 川﨑 了, 中原拓郎
    土木学会論文集 2003 736 93 - 102 公益社団法人 土木学会 2003年 [査読有り][通常論文]
     
    本研究ではダイレイタンシー拘束条件下における, 人工岩を用いた一面せん断試験を行うことによって, そのせん断特性の把握を試みた. また, 異なるせん断方向におけるせん断特性の違いに関してもせん断試験を行うことによって検討を行った. それらのせん断試験の結果, せん断特性がせん断破壊の進行とともに破断するアスペリティーに大きく影響されることがわかった. そこで, 破断するアスペリティーの体積を推定する手法を考案し, その破断されるアスペリティーの体積をパラメータとして用いたせん断強度式を新たに提案した. そして, 自然岩に関する一面せん断試験を行い, 提案したせん断強度式の適用性について考察した.
  • 谷本親伯, 北村義宜, 川﨑 了, 宮田健治朗, 鈴木淳也
    土木学会論文集 2002 715 83 - 94 公益社団法人 土木学会 2002年 [査読有り][通常論文]
     
    岩盤のせん断挙動には不連続面の凹凸が大きく関係しており, 凹凸と強度・変形特性との関係を明らかにすることは, 岩盤のせん断挙動を推定する上で重要である. この凹凸がせん断挙動に及ぼす影響は, せん断試験条件によって大きく異なるが, これまで試験条件によるせん断挙動の違いは十分に明らかにされていない. そこで本研究では自然の状態を保つ不連続面を有する人工供試体を作成し, 定圧およびダイレイタンシー拘束条件において一面せん断試験を行い, それぞれの試験条件におけるせん断強度特性について考察を行った. 特に, せん断中にアスペリティーが破断して変形を起こす状態を定量的に評価する手法を考案し, それぞれの試験条件においてアスペリティーの破断体積とせん断強度の間に高い相関が存在することを見出した.
  • 谷本親伯, 宮田健治朗, 川﨑 了, 北村義宜, 鈴木淳也
    土木学会論文集 2002 715 95 - 105 公益社団法人 土木学会 2002年 [査読有り][通常論文]
     
    本研究では, 自然の不連続面と同じ形状を有する人工供試体を作成し, 拘束圧一定条件とダイレイタンシー拘束条件の2つの異なる条件において一面せん断試験を行い, せん断試験と同時に弾性波伝播挙動を測定した. すなわち, 計測データから弾性波速度および第一波振幅値の算出を行い, せん断破壊の進展状態と振幅値の相関関係を考察した. また, 不連続面の表面形状が弾性波伝播挙動に与える影響を調べるためにラフネスの定量化も行った. これらの基礎実験の結果から, 弾性波ジオトモグラフィーを適用した場合の結果解析に当り, 弾性波伝播特性によって岩盤の緩み領域を評価することができるものと考える.
  • 川﨑 了, 谷本親伯, 小泉和広, 石川正基
    応用地質 43 4 244 - 248 一般社団法人日本応用地質学会 2002年 [査読有り][通常論文]
     
    国内の数地点より採取された岩石コアを対象としたエコーチップ硬さ試験,一軸圧縮試験および弾性波試験を行い,得られた硬さ指標と力学特性の相関関係について検討を実施した.その結果,硬さ指標を用いて岩石の一軸圧縮強度が大略推定できる可能性が大きいことがわかった.
  • S Kawasaki, M Yoshida, C Tanimoto, T Masuya
    ROCK MECHANICS: A CHALLENGE FOR SOCIETY 103 - 108 2001年 [査読無し][通常論文]
     
    The Equotip hardness tester is one of the useful testers developed so as to understand elastic properties and strengths of metallic materials. It is picked up as the characteristics of the rester that a small sample is needed for the test, sampling time is short, and the tester is convenient for portable use. In case of applying the rester to an actual structure constructed in or on rock mass and a stone cultural heritage whose shape is complex, it is therefore expected that the tester is able to measure rapidly toward all test directions in the field. For the purpose of newly developing an evaluation method for rock materials using the tester, this paper reports on especially two objects such as 1) investigations on the effects of test conditions (i.e. considerations on the size, shape and roughness of rock samples), and 2) investigations on fundamental properties of unweathered rock samples (i.e. considerations on the relationships to physical and mechanical properties).
  • 風化岩を対象とした簡易反発硬度試験の適用性
    吉田昌登, 川﨑 了, 谷本親伯, 舛屋 直
    第31回岩盤力学に関するシンポジウム講演論文集 97 - 101 2001年 [査読無し][通常論文]
  • S Kawasaki, C Tanimoto
    FRONTIERS OF ROCK MECHANICS AND SUSTAINABLE DEVELOPMENT IN THE 21ST CENTURY 413 - 416 2001年 [査読無し][通常論文]
     
    The authors have investigated the deterioration phenomena, conservation and restoration of stone cultural heritages from the viewpoint of rock mechanics. This paper shows the state of the art of deterioration examinations, conservation and restoration of stone Buddha images in Japan.
  • エコーチップ反発硬度試験の岩石材料への適用性
    吉田昌登, 川﨑 了, 谷本親伯, 舛屋 直
    第30回岩盤力学に関するシンポジウム講演論文集 308 - 312 2000年 [査読無し][通常論文]
  • 川﨑 了, 吉田昌登, 谷本親伯, 舛屋 直
    応用地質 41 4 230 - 241 一般社団法人日本応用地質学会 2000年 [査読有り][通常論文]
     
    金属材料の弾性的性質や強度の把握を目的として開発された試験機の中に, スイス製のエコーチップ硬さ試験機がある.本試験機の特徴としては, 対象とする供試体が小さくて済むことや, 試験時間が短時間であること, 小型で計量であることから携帯性に優れていること, などが挙げられる.よって, 本試験機を実際の岩盤構造物や複雑な形状をした石造文化遺産に対して用いれば, 計測方向に関係なく迅速な作業が現場で可能になるものと期待される.本試験機を用いた岩質材料の物性評価手法を新たに開発するために, 本論文ではとくに, (1)試験条件が与える影響調査(岩石の寸法・形状や表面粗度などに関する検討), (2)新鮮な岩石を用いた基本特性調査(物理・力学特性との相関などに関する検討)の2項目に関して実施した結果を報告する.
  • 宮田健治朗, 谷本親伯, 川﨑 了, 舛屋 直
    第30回岩盤力学に関するシンポジウム講演論文集 178 - 182 2000年 [査読無し][通常論文]
  • 室内試験による岩石の比抵抗に関する基礎的研究
    西澤亮総, 谷本親伯, 川﨑 了, 舛屋 直
    第30回岩盤力学に関するシンポジウム講演論文集 188 - 192 2000年 [査読無し][通常論文]
  • 岩盤不連続面の表面形状の定量化とせん断強度の推定に関する研究
    北村義宜, 谷本親伯, 川﨑 了, 舛屋 直
    第30回岩盤力学に関するシンポジウム講演論文集 348 - 352 2000年 [査読無し][通常論文]
  • 二種混合体の圧縮特性に関する解析的検討-礫岩の強度評価へのアプローチ-
    中本 崇, 西村 強, 川﨑 了, 木山英郎
    第30回岩盤力学に関するシンポジウム講演論文集 338 - 342 2000年 [査読無し][通常論文]
  • 川﨑 了, 中川加明一郎, 江藤芳武, 野崎明人, 小泉和広
    土木学会論文集 617 617 77 - 87 公益社団法人 土木学会 1999年 [査読有り][通常論文]
     
    地下構造物を大深度礫岩に建設する際には, 礫の影響によりコアの強度および剛性が原位置岩盤よりも過大に評価されたり, 逆に, サンプリングによる乱れの影響によって, 原位置岩盤よりも過小に評価されることが想定される. そこで, 深度600mのボーリングコアを用いた大深度礫岩の室内試験を実施し, 礫岩コアの品質評価を行った. その結果, 礫岩コアの品質に影響を与えるサンプリングによる乱れには, 礫分含有率と方解石含有率の2つが複雑に関与しており, 特に, 方解石含有率が小さく礫分含有率が小さいほど, 礫岩コアがサンプリングによる乱れの影響を受けやすいことがわかった.
  • S Kawasaki, H Ito, K Nakagawa, Y Eto, A Nozaki, K Koizumi
    NINTH INTERNATIONAL CONGRESS ON ROCK MECHANICS, VOLS 1 & 2 619 - 622 1999年 [査読無し][通常論文]
     
    To conduct a quality evaluation of conglomerate core samples, a series of laboratory rock tests using conglomerate core samples obtained from the depth of 600m and artificial conglomerate core samples was carried out. This paper shows that the sample disturbance by core sampling which gives influences to the quality of conglomerate core samples is complicatedly concerned with gravel faction content and calcite content. Especially the smaller the calcite content is, and moreover, the smaller the gravel fraction content is, the more extensively the sample disturbance by core sampling is influenced.
  • 川﨑 了, 小泉和広
    応用地質 39 2 202 - 207 1998年 [査読有り][通常論文]
  • 川﨑 了, 伊藤 洋, 小泉和広
    応用地質 39 4 391 - 400 1998年 [査読有り][通常論文]
  • 川﨑 了, 中川加明一郎, 江藤芳武, 野崎明人, 小泉和広
    第10回岩の力学国内シンポジウム講演論文集 797 - 802 1998年 [査読無し][通常論文]
  • 川﨑 了, 中川加明一郎, 小泉和広
    応用地質 39 3 273 - 281 一般社団法人日本応用地質学会 1998年 [査読有り][通常論文]
     
    岩石においても有効応力の原理が適用できるとの立場から, 土質材料と同様に圧密現象を計測することによって難透水性材料である岩石の透水係数の推定を試みた.対象とした岩石は, 堆積岩である軟質泥岩と硬質礫岩である.その結果, 三軸試験装置を用いた等方圧密試験により得られた透水係数と注水試験による透水係数を比較して, 両者に良好な対応関係が見られた.本透水係数推定法の特徴は, 通常実施されている圧密過程を伴う三軸試験と透水試験の2つの試験が, 三軸試験の1つだけで実施できる点にあり, 有効な簡易透水係数推定法の1つと考えられる.
  • 川﨑 了, 西 好一, 岡本敏郎
    土木学会論文集 589 589 79 - 90 土木学会 1998年 [査読有り][通常論文]
  • 軟岩地盤での圧縮空気貯槽建設コストのパラメトリックスタディ
    川﨑 了, 岡本敏郎, 田中幸久
    地下空間シンポジウム論文・報告集 2 175 - 179 1997年 [査読無し][通常論文]
  • S Kawasaki, T Okamoto, Y Tanaka, S Hibino
    TUNNELS FOR PEOPLE, VOLS 1 AND 2 835 - 840 1997年 [査読無し][通常論文]
     
    The CAES-GT system, in which a compressed air energy storage cavern constructed in deep ground is combined with a gas turbine generator, is attracting wide attention. The feasibility of this CAES-GT system depends on whether it is economic to construct a compressed air energy storage facility deep underground. This paper shows the characteristics and feasibility of construction method for compressed air storage facilities in deep soft rock ground.
  • Measurement of pore pressure distribution in deep rock and its application to estimating underground water flow
    Nakagawa, K, Kawasaki, S, Shidahara, T, Eto, Y, Nozaki, A
    Proceedings of the International Symposium on Rock Mechanics and Environmental Geotechnology 477 - 481 1997年 [査読無し][通常論文]
  • 川﨑 了, 中川加明一郎, 江藤芳武, 野崎明人, 小泉和広
    応用地質 38 5 296 - 298 1997年 [査読有り][通常論文]
  • 川﨑 了, 中川加明一郎, 江藤芳武, 野崎明人, 小泉和広
    応用地質 38 5 252 - 264 一般社団法人日本応用地質学会 1997年 [査読有り][通常論文]
     
    大深度の礫岩物性を調査する目的で、深度600mの大深度ボーリング調査を実施し、採取した礫岩コアを用いた室内岩石試験を行った。また、礫岩の力学特性に大きく影響を与えると思われる充填鉱物として、とくに方解石含有率について着目し、方解石含有率と礫岩の物性値との関係について調べるために方解石含有率の定量化を試みた。これらの結果、方解石含有率と応力解放に伴う礫岩コアのゆるみの影響を考慮することによって、大深度堆積礫岩の室内試験結果が評価できることが明らかとなった。
  • 大深度軟岩地盤における立坑掘削挙動を模擬した室内模型実験
    川﨑 了, 岡本敏郎, 田中幸久
    第27回岩盤力学に関するシンポジウム講演論文集 111 - 115 1996年 [査読無し][通常論文]
  • 岡本敏郎, 田中幸久, 川﨑 了, 日比野敏
    応用地質 35 6 264 - 272 一般社団法人日本応用地質学会 1995年 [査読有り][通常論文]
     
    Geological conditions should be considered when a storage cavern is constructed in rock ground for compressed air energy storage gas turbine generator which is hopeful as electric power storage in near future, and muddy slurry excavation and steel pipe shaft method is proposed in soft rocks. The water replacement type and dry type are typical in the method and their basic characteristics are studied in this paper. Most important things in realizing this method are both feasibility of excavating a cavern and its economic advantage, especially present evaluation of cavern stability in muddy slurry excavation and economically optimum depth in positioning a cavern are studied in this paper.
  • 定ひずみ速度圧密試験法の堆積軟岩への適用
    川﨑 了, 西 好一, 高橋 浩
    第25回岩盤力学に関するシンポジウム講演論文集 126 - 130 1993年 [査読無し][通常論文]
  • S KAWASAKI, K NISHI, Y FUJIWARA
    GEOTECHNICAL ENGINEERING OF HARD SOILS - SOFT ROCKS, VOL 1 593 - 600 1993年 [査読無し][通常論文]
  • Construction technology of compressed air storage tank in soft rock ground for CAES-GT generation
    Nishi, K, Kawasaki, S, Fujiwara, Y, Hibino, S
    Proceedings of the 2nd International Compressed Air Energy Storage Conference 1 - 16 1992年 [査読無し][通常論文]

書籍

  • Stabilization/solidification of mining waste via biocementation. In: Daniel C.W. Tsang, Lei Wang (eds) Low Carbon Stabilization and Solidification of Hazardous Wastes
    Wilson Mwandira, Kazunori Nakashima, Satoru Kawasaki 
    Elsevier, Netherlands 2021年09月
  • Biocementation technology for stabilization/solidification of organic peat. In: Daniel C.W. Tsang, Lei Wang (eds.) Low Carbon Stabilization and Solidification of Hazardous Wastes
    Sivakumar Gowthaman, Meiqi Chen, Kazunori Nakashima, Shin Komatsu, Satoru Kawasaki 
    Elsevier, Netherlands 2021年09月
  • The Amendments in Typical Microbial Induced Soil Stabilization by Low-Grade Chemicals, Biopolymers and Other Additives: A Review. In: V. Achal and C. S. Chin (eds.) Building Materials for Sustainable and Ecological Environment
    Sivakumar Gowthaman, Thiloththama Hiranya Kumari Nawarathna, Pahala Ge Nishadi Nayanthara, Kazunori Nakashima, Satoru Kawasaki 
    Springer, Singapore 2021年05月
  • 地盤材料試験の方法と解説(第一回改訂版)
    地盤工学会 2020年12月
  • Effect of Plant-Derived Urease-Induced Carbonate Formation on the Strength Enhancement of Sandy Soil. In: Achal V., Mukherjee A. (eds) Ecological Wisdom Inspired Restoration Engineering
    Dilrukshi R.A.N, Kawasaki S 
    Springer, Singapore 2018年08月
  • Utilization of Microbially Induced Calcite Precipitation for Sand Solidification Using Pararhodobacter sp.. In: Achal V., Mukherjee A. (eds) Ecological Wisdom Inspired Restoration Engineering
    Amarakoon G.G.N.N, Kawasaki S 
    Springer, Singapore 2018年08月
  • Making Artificial Beachrock Through Bio-cementation: A Novel Technology to Inhibition of Coastal Erosion. In: Hussain C. (eds) Handbook of Environmental Materials Management
    Khan M.N.H, Kawasaki S 
    Springer, Cham 2018年01月
  • 地盤材料試験の方法と解説
    地盤工学会 2009年
  • 岩の試験・調査方法の基準・解説書-平成18年度版-
    地盤工学会 2006年
  • 『残壁ハンドブック』<資源・素材学会残壁ハンドブック編集委員会>
    資源・素材学会 2005年
  • 岩の試験・調査方法の基準・解説書-平成14年度版-
    地盤工学会 2003年
  • 『ロックメカニクス』<日本材料学会編>
    技報堂出版 2002年

その他活動・業績

特許

  • 特願2016-157306:海岸・河岸保全工法  2016年08月10日
    川﨑 了, 宇次原雅之
  • 特許公開2012-172060:グラウトおよび地盤を固結する方法  2012年09月10日
    川﨑 了, 秋山 克
  • 特許4621634:微生物を用いたカルシウムを含む地盤の固結方法    2011年01月26日
    川﨑 了, 廣吉直樹, 島田俊介, 小山忠雄, 寺島 麗  
    特開2008-8023
  • 特許4608669:微生物を用いたカルシウムを含む地盤改良方法    2011年01月12日
    川﨑 了, 廣吉直樹, 島田俊介, 小山忠雄, 寺島 麗  
    特許公開2008-184741
  • 特許4599611:地盤改良工法およびその工法に用いるグラウト    2010年12月15日
    川﨑 了, 廣吉直樹  
    特許公開2006-169940
  • 特許4517050:地盤改良方法及びその装置    2010年05月28日
    川﨑 了, 廣吉直樹, 島田俊介, 小山忠雄, 寺島 麗  
    特許公開2008-231769
  • 特願2007-27076:気泡ボーリング用気泡剤  2007年02月06日
    川﨑 了, 小宮国盛  
    特許公開2008-190251
  • 特許公開2001-200526:微生物による構造物材料の風化加速方法  2001年07月27日
    川﨑 了, 武田克史  
    特開2001-200526
  • 特許公開2001-200525:微生物による構造物材料の物性改良方法  2001年07月27日
    川﨑 了, 武田克史  
    特開2001-200525
  • 特許公開平11-236708:ワイヤーラインによるセルフボーリング型プレッシャーメータ試験方法  1999年08月31日
    川﨑 了  
    特開平11-236708
  • 特開2008-63495:土または建造物躯体の処理方法  
    島田俊介, 小山忠雄, 寺島 麗, 川﨑 了, 廣吉直樹  
    特許公開2008-63495

受賞

  • 2021年11月 The GEOMATE International Society The Eleventh International Conference on Geotechnique, Construction Materials and Environment (GEOMATE 2021) Best Paper Award
  • 2018年11月 The GEOMATE International Society The Eighth International Conference on Geotechnique, Construction Materials and Environment (GEOMATE 2018) Best Paper Award
  • 2016年02月 北海道大学 平成27年度教育総長賞
     
    受賞者: 川﨑 了
  • 2012年11月 The GEOMATE International Society The Second International Conference on Geotechnique, Construction Materials and Environment (GEOMATE 2012) Keynote Paper Award
     
    受賞者: 川﨑 了
  • 2012年06月 地盤工学会 平成23年度地盤工学会賞論文賞(和文部門)
  • 2008年05月 日本応用地質学会 第18回日本応用地質学会論文賞
     
    受賞者: 川﨑 了

共同研究・競争的資金等の研究課題

  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2022年04月 -2025年03月 
    代表者 : 川崎 了
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 川崎 了
     
    本年度は,①尿素分解菌に関する検討,②培養試験および強度発現メカニズムに関する検討,③小型円筒容器を用いた室内固化試験,④斜面模型を用いた室内固化試験,の4項目に関する研究を実施した。得られた主な成果の概要は,次のとおりである。 ①尿素分解菌に関する検討:国内の各地から採取した地盤材料を用いた物理試験と化学試験を行うと同時に,地盤材料中に生息する尿素分解菌の分離・単離試験を実施した。また,単離した尿素分解菌のウレアーゼ活性に関する温度依存性,pH依存性について調査を行った。その結果,北海道の地盤材料より単離され,ウレアーゼ活性の至適温度が20~25℃付近にあり,その値が10日間持続するLysinibacillus xylanilyticusが最も有望な菌株であることがわかった。 ②培養試験および強度発現メカニズムに関する検討:培養試験により,Lysinibacillus xylanilyticusの最適な培養条件を明らかにした。また,培養および固化に必要な材料として,高価な試薬の使用以外に安価な代替品の適用性について検討を実施した結果,代替品の適用が可能であることが示唆された。 ③小型円筒容器を用いた室内固化試験:Lysinibacillus xylanilyticusを用いて,炭酸カルシウムの析出条件を変化させた地盤材料の室内固化試験を実施した。また,固化した地盤材料の一軸圧縮強さ(UCS)を針貫入試験で推定したところ,数MPa程度を1カ月程度で達成した。 ④斜面模型を用いた室内固化試験:切土法面を想定した斜面模型による室内固化試験を実施し,固化した斜面表層部の炭酸カルシウム含有量や針貫入試験による推定UCSの分布特性を調査した。
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2016年04月 -2019年03月 
    代表者 : 川崎 了
     
    本研究の目的は,海岸域の自然材料(微生物,海水,海砂,貝殻片など)を用いてCaCO3の析出により固化した人工ビーチロックを作製し,港湾岸壁のコンクリートの一軸圧縮強さ20~30 MPa程度を1カ月程度で達成する基本技術を新たに開発し,その有効性を確認することである。 国内の海岸域においてウレアーゼ活性が高い尿素分解菌を探索した結果,沖縄県や北海道などの土質試料よりCaCO3析出に適した菌株が発見された。また,砂供試体の室内加速固化試験を実施した結果,試験開始から3週間後に針貫入試験による推定一軸圧縮強さ約20 MPaが得られた。結論として,新たに開発された技術の有効性が確認された。
  • 自然に学ぶ新しい国土修復保全技術に関する基礎的研究
    鹿島学術振興財団:2016年度 研究助成(継続)
    研究期間 : 2017年04月 -2018年03月 
    代表者 : 川﨑 了
  • 現地の微生物を利用した新しい地盤固化技術の実証
    イムラ・ジャパン株式会社:先進技術シーズ研究への研究助成「第1回イムラ・ジャパン賞」助成金
    研究期間 : 2017年04月 -2018年03月 
    代表者 : 川﨑 了
  • 自然に学ぶ新しい国土修復保全技術に関する基礎的研究
    鹿島学術振興財団:2015(平成27)年度 研究助成
    研究期間 : 2016年04月 -2017年03月 
    代表者 : 川﨑 了
  • 現地の微生物を利用した国土の新しい自己修復保全技術の開発
    八洲環境技術振興財団:平成27年度 研究開発・調査助成
    研究期間 : 2016年04月 -2017年03月 
    代表者 : 川﨑 了
  • 自然のビーチロック形成メカニズムに学ぶ国土の自己修復保全に関する技術開発
    住友財団:2015年度 環境研究助成
    研究期間 : 2015年11月 -2016年10月 
    代表者 : 川﨑 了
  • ビーチロックに学ぶ国土修復保全技術の開発
    積水化学工業:積水化学 自然に学ぶものづくり研究助成プログラム
    研究期間 : 2015年10月 -2016年09月 
    代表者 : 川﨑 了
  • ビーチロックに学ぶ新しい国土修復保全技術の開発
    戸田育英財団:平成27年度研究助成
    研究期間 : 2015年07月 -2016年03月 
    代表者 : 川﨑 了
  • 自然に学ぶ海岸構造物の自己修復技術に関する研究
    国土技術研究センター:平成26年度(第16回)国土技術研究センター研究開発助成
    研究期間 : 2015年04月 -2016年03月 
    代表者 : 川﨑 了
  • 自然に学ぶコンクリート構造物の新しい修復・保全技術の開発
    東日本高速道路:NEXCO東日本技術研究助成
    研究期間 : 2015年01月 -2015年12月 
    代表者 : 川﨑 了
  • 日本学術振興会:科学研究費補助金(基盤研究(B))
    研究期間 : 2012年04月 -2015年03月 
    代表者 : 川﨑 了
  • ビーチロック形成機構に学ぶ新しい地盤固化技術の開発
    前田記念工学振興財団:平成24年度研究助成
    研究期間 : 2012年04月 -2013年03月 
    代表者 : 川﨑 了
  • ビーチロック形成機構に学ぶ新しい液状化対策技術に関する基礎的研究
    大林財団:平成23年度研究助成
    研究期間 : 2012年04月 -2013年03月 
    代表者 : 川﨑 了
  • シリカを用いた地盤のバイオ固化処理の有効性評価
    北海道ガス:大学研究支援制度
    研究期間 : 2011年04月 -2012年03月 
    代表者 : 川﨑 了
  • 微生物機能を利用した環境保全型保存材料の提案
    日本学術振興会:科学研究費補助金(基盤研究(B))
    研究期間 : 2009年04月 -2012年03月 
    代表者 : 川﨑 了
  • 微生物の代謝活動により固化する新しい保存材料の作製と評価
    日本学術振興会:科学研究費補助金(基盤研究(B))
    研究期間 : 2006年04月 -2009年03月 
    代表者 : 川﨑 了
  • 寒冷地を想定した低温環境下におけるバイオグラウトの有効性評価
    北海道ガス:大学助成金
    研究期間 : 2006年04月 -2007年03月 
    代表者 : 川﨑 了
  • 微生物代謝により固化する新しいグラウトの開発に関する基礎的研究
    文部科学省:科学研究費補助金(萌芽研究)
    研究期間 : 2005年04月 -2007年03月 
    代表者 : 川﨑 了
  • 簡易反発硬度試験による石造文化遺産の健全度調査手法の開発
    文部科学省:科学研究費補助金(奨励研究(A))
    研究期間 : 2000年04月 -2002年03月 
    代表者 : 川﨑 了
  • 平成14年度少壮研究者による海外学術研究調査
    日本鉱業振興会:少壮研究者による海外科学技術研究調査助成
    研究期間 : 2002年 -2002年 
    代表者 : 川﨑 了
  • Fundamental Study on Novel Grout Cementing Due to Microbial Metabolism
    研究期間 : 2001年

教育活動情報

主要な担当授業

  • 地圏計測工学
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 工学院
    キーワード : 室内試験,原位置試験,計測,軟岩,風化,強度,変形,物性評価
  • 地圏計測工学特論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 工学院
    キーワード : 室内試験,原位置試験,計測,軟岩,風化,強度,変形,物性評価
  • 地圏計測工学特論
    開講年度 : 2021年
    課程区分 : 博士後期課程
    開講学部 : 工学院
    キーワード : 室内試験,原位置試験,計測,軟岩,風化,強度,変形,物性評価
  • 計測工学
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 計測,誤差,センサー,物理探査法
  • 資源循環システム実験Ⅲ
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 構造解析,物性評価,鉱物の利用,流体の分析,選別技術
  • 資源循環システム実験Ⅱ
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : X線回折,岩石の構造,岩石の工学的性質,鉱物,地質図,地質巡検,偏光顕微鏡
  • 微生物工学
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 生化学,分子生物学,酵素反応,微生物反応,反応速度論,バイオリアクター,極限環境微生物,バイオミネラリゼーション,バイオリーチング
  • 資源工学概論
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 鉱物資源 鉱床 探査・開発技術 環境問題 未利用資源 リサイクル

大学運営

委員歴

  • 2019年 - 現在   土木学会   岩盤力学委員会 岩盤力学改訂版編集小委員会 執筆者 執筆委員
  • 2015年 - 現在   札幌市   廃棄物処理施設設置等評価委員会 委員
  • 2010年 - 現在   北海道開発局   道路防災有識者
  • 2004年 - 現在   土木学会 岩盤力学委員会   委員
  • 2003年 - 現在   資源・素材学会 岩盤工学部門委員会   委員
  • 2003年 - 現在   資源・素材学会 北海道支部   常議員   社団法人 資源・素材学会
  • 2017年 - 2022年   北海道環境保全技術協会   北海道新幹線、新函館北斗・札幌間自然由来重金属等掘削土対策検討委員会 委員
  • 2018年 - 2020年   札幌市   環境影響評価審議会 会長
  • 2018年 - 2020年   資源・素材学会 北海道支部   支部長
  • 2018年 - 2020年   資源・素材学会   理事
  • 2017年 - 2020年   地盤工学会   次世代地盤改良技術に関する研究委員会 委員
  • 2016年 - 2020年   地盤工学会   室内試験規格・基準委員会 WG1:物理特性 メンバー
  • 2017年 - 2019年   北海道環境保全技術協会   北海道新幹線、新函館北斗・札幌間自然由来重金属等掘削土対策検討委員会 幹事会 幹事
  • 2015年 - 2019年   日本材料学会   代議員
  • 1998年 - 2019年   日本材料学会 岩石力学部門委員会   委員
  • 2014年 - 2018年   札幌市   環境影響評価審議会 委員
  • 2013年 - 2018年   ICE Publishing   International Editorial Board of Environmental Geotechnics Editorial Board Member
  • 2014年 - 2017年   地盤工学会   地盤調査および室内試験基準の英訳化に関する実行委員会 委員
  • 2014年 - 2016年   土木学会   土木学会論文集編集委員会C分冊編集小委員会 委員
  • 2013年 - 2016年   地盤工学会   室内試験規格・基準委員会 委員長
  • 2013年 - 2015年   ASEAN Engineering Journal Editorial Broad Member in Geological and Geo-Resource Engineering
  • 2014年 - 2014年   資源・素材学会   Journal of MMIJ編集委員会 委員
  • 2012年 - 2014年   2014 ISRM International Symposium ARMS8 (The 8th Asian Rock Mechanics Symposium)   Organizing Committee Vice Secretary General
  • 2012年 - 2014年   岩の力学連合会   第8回アジア地域岩の力学シンポジウム(ARMS)組織委員会 委員兼副幹事長
  • 2008年 - 2014年   地盤工学会 北海道支部   幹事
  • 2012年 - 2013年   資源・素材学会 Journal of MMIJ編集委員会   編集幹事
  • 2011年 - 2013年   地盤工学会   室内試験規格・基準委員会 岩石の繰返し強度試験方法基準化WG メンバー
  • 2010年 - 2011年   資源・素材学会 Journal of MMIJ編集委員会   委員
  • 2009年 - 2011年   土木学会   教育企画・人材育成委員会 大学・大学院小委員会 委員
  • 2009年 - 2011年   地盤工学会   室内試験規格・基準委員会 岩石および岩盤不連続面の動的繰返し強度・変形試験方法基準化検討WG メンバー
  • 2006年 - 2010年   北海道道路管理技術センター   道路防災ドクター
  • 2006年 - 2009年   地盤工学会   室内試験規格・基準委員会 WG11:赤本改訂版の総説執筆 WG幹事
  • 2006年 - 2009年   地盤工学会   室内試験規格・基準委員会 WG1:物理特性 メンバー
  • 2006年 - 2009年   地盤工学会   室内試験規格・基準委員会 委員兼幹事
  • 2006年 - 2009年   地盤工学会   基準部 部員
  • 2005年 - 2009年   岩の力学連合会   電子ジャーナル委員会 編集委員兼幹事
  • 2006年 - 2007年   岩の力学連合会   企画委員会 委員
  • 2006年 - 2007年   岩の力学連合会   ISRM2007コングレス国内審査委員会 委員
  • 2004年 - 2006年   土木学会   岩盤力学委員会 論文小委員会 委員長
  • 2004年 - 2006年   土木学会   論文賞選考委員会 委員
  • 2004年 - 2006年   地盤工学会   岩石のスレーキング試験方法基準化委員会 委員長
  • 2002年 - 2006年   地盤工学会   岩の試験・調査規格・基準検討委員会 委員
  • 1998年 - 2006年   土木学会   岩盤力学委員会 運営小委員会 委員
  • 2004年 - 2005年   岩の力学連合会   賞表彰委員会 委員
  • 2003年 - 2005年   土木学会   岩盤力学委員会 企画小委員会 委員
  • 2002年 - 2005年   資源・素材学会 北海道支部   幹事   社団法人 資源・素材学会
  • 1996年 - 2004年   土木学会   岩盤力学委員会 論文小委員会 委員
  • 2002年 - 2003年   土木学会   岩盤力学委員会 論文小委員会 幹事
  • 2001年 - 2003年   The Third International Symposium on Rock Stress (RS Kumamoto '03) Organizing Committee   Member
  • 2001年 - 2003年   地盤工学会 岩盤のせん断試験方法基準化委員会   委員   地盤工学会 岩盤のせん断試験方法基準化委員会
  • 2001年 - 2002年   土木学会   トンネル工学委員会 トンネル工学研究発表会小委員会 委員兼幹事
  • 2001年 - 2002年   地盤工学会   第31回地盤工学研究発表会実行委員会 研究発表講演部会 委員
  • 2000年 - 2002年   岩の力学連合会   第11回岩の力学国内シンポジウム運営委員会 委員
  • 2000年 - 2002年   地盤工学会   軟岩の圧密非排水(CU,CUバー)三軸圧縮試験方法基準化委員会 委員兼幹事   地盤工学会
  • 1999年 - 2002年   地盤工学会 関西支部   幹事
  • 1999年 - 2002年   土木学会 岩盤力学委員会 深地層における軟岩の評価に関する研究小委員会   委員兼幹事   土木学会 岩盤力学委員会 深地層における軟岩の評価に関する研究小委員会
  • 1998年 - 2002年   日本建設機械化協会 関西支部   技術部会 トンネル施工機材委員会 委員兼幹事
  • 1998年 - 2000年   土木学会 岩盤力学委員会 軟岩小委員会   委員兼幹事
  • 1998年 - 2000年   地盤工学会 岩の三軸圧縮試験方法基準化委員会   委員   地盤工学会 岩の三軸圧縮試験方法基準化委員会
  • 1995年 - 1998年   地盤工学会   土質試験基準検討委員会 委員
  • 1995年 - 1998年   地盤工学会   土質試験基準検討委員会 せん断試験小委員会 委員
  • 1995年 - 1998年   地盤工学会   土の一面せん断試験方法基準化委員会 委員
  • 1995年 - 1998年   地盤工学会 岩石の超音波速度測定方法基準化委員会   委員兼幹事   地盤工学会 岩石の超音波速度測定方法基準化委員会
  • 1990年 - 1998年   土木学会 岩盤力学委員会 軟岩小委員会   委員   土木学会 岩盤力学委員会 軟岩小委員会
  • 1992年 - 1994年   土質工学会   大深度地下利用に関する地盤工学研究委員会 委員


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