Dr. of Engineering, Tokyo Institute of Technology

long-term consolidation

埋立て

軟弱粘土

地盤調査

ground improvement

Geo-environmant

廃棄物

Reclamation

Geotechnical Investigation

Soft Clay

Waste

Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention), Geotechnical engineering

Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention), Environmental systems for civil engineering

Bachelor's degree program, School of Engineering

Master's degree program, Graduate School of Engineering

Doctoral (PhD) degree program, Graduate School of Engineering

2019, Japan Society of Civil Engineers, Best Paper Award
港湾鋼構造物の海底土中部の電気防食特性および土壌抵抗率を考慮した電気防食設計に関する検討

2016, Award for Distinguished Service, Japanese Geotechnical Society
WATABE Yoichi

2014, Japanese Society of Geotechnical Engineering, Best Paper Award
Ecological geotechnics: Role of waterfront geoenvironment as habitats in the activities of crabs, bivalves, and birds for biodiversity restoration

2014, 土木学会国際活動奨励賞受賞
渡部 要一

2013, Japanese Society of Geotechnical Engineering, Technology Development Award
Sedimentary stratigraphy of natural intertidal flats with various characteristics
渡部要一

2007, The Ports and Harbours Association of Japan, Best Paper Award
防波堤マウンドの期待変形量に関する研究
渡部要一;下迫健一郎;浅沼丈夫;稲垣正芳;諫山太郎, Japan

2006, Japan Society for Civil Engineers, Best Paper Award of Coastal Engineering
Japan

2001, Canadian Geotechnical Society, Honorable Mention for R.M.Quigley Award,

1996, Japan Society of Civil Engineering's Praise for Outstanding Young Researchers.

1996, Tokyo Institute of Technology's Praise for Ph.D. thesis ("Tejima" Memorial Award).

1992, Ph.D. Scholarship Awarded by Tokyo Institute of Technology.

Experimental study for modeling the unloading swelling behavior of Ariake clay
Zheng Fan; Yoichi Watabe
Soils and Foundations, 65, 3, 101594, 101594, Elsevier BV, Jun. 2025, [Peer-reviewed]
Scientific journal

Re-examination and analysis of test data on consolidation of soft soils exhibiting creep with different thicknesses
Pei-Chen Wu; Ze-Jian Chen; Jian-Hua Yin; Yoichi Watabe; Ding-Bao Song; Peng-Lin Li
Géotechnique, 1, 11, Emerald, 13 Dec. 2024, [Peer-reviewed]
Scientific journal, Accurate prediction regarding the long-term settlements of soft soils is challenging. One of the reasons for this is time-dependent soil behaviours. How to extrapolate such behaviours from thin laboratory testing with limited timescales to an in situ thick soil layer with large timescales is still an ongoing debate, which can be dated back to the work of Ladd and co-workers in 1977. Many experimental results that were previously used to advocate hypothesis A have been re-analysed and found to align with hypothesis B. However, discrepancies remain in some historical data, particularly in the case of Osaka clay retrieved from the seabed under the Kansai international airport islands. This study begins by introducing the main implications and selected existing models for the time-dependent behaviours of soft soil. It then focuses on the re-examination of selected test results from the work of Watabe and co-workers in 2008, supplemented by numerical simulation using isotache models. The analysis emphasises the importance of considering equal initial conditions when comparing data from samples with varying thicknesses. Furthermore, the good agreement observed between measured data and the simulation results using hypothesis B methods demonstrates the validity of hypothesis B for predicting the long-term consolidation behaviour of soft soil both in the laboratory and at field scales.

Application of the isotache law and the power creep law on prediction of long-term consolidation behaviour
Y. Watabe; Y. Miyata
Proceedings of the XVIII ECSMGE 2024, Geotechnical Engineering Challenges to Meet Current and Emerging Needs of Society, 935, 938, CRC Press, 17 Sep. 2024, [Peer-reviewed], [Lead author]
In book

Centrifuge model test focusing on deformation behavior after preload removal on soft ground and its evaluation
Daisuke Niina; Yoichi Watabe
Japanese Journal of JSCE, 80, 18, 24-18128, Japan Society of Civil Engineers, 2024, [Peer-reviewed]
Scientific journal

Suffusion in densely compacted Satozuka pumice sand and its impact on static loading undrained shear strength and dilation behaviour
Rupali Sarmah; Yoichi Watabe
Soils and Foundations, 63, 6, 101397, 101397, Elsevier BV, Dec. 2023, [Peer-reviewed]
Scientific journal

Influence of compaction conditions on the liquefaction characteristics of pumice sand with non-plastic fines
Yoichi Watabe
Bulletin of L.N. Gumilyov Eurasian National University. Technical Science and Technology Series, 143, 2, 8, 18, L. N. Gumilyov Eurasian National University, 30 Jun. 2023, [Peer-reviewed], [Lead author]
Scientific journal, In this study, the liquefaction characteristics of pumice sand were investigated focusing on the relationship with compaction conditions. The new findings obtained in this study are summarized as follows. In the pumice sand with a large amount of non-plastic fines, liquefaction resistance RL20 can be expected to be only about 0.2 at a degree of compaction of 90%, however, it can be increased to be 0.3 or more if the soil is densified by compaction up to degree of compaction of 95% or more. In addition, the skeletal structure is also important even at the same dry density, and a higher liquefaction resistance can be expected under the compaction conditions on a dryer condition in water content at compaction. On the other hand, the tenacity for deformation in liquefaction under cyclic loading may be lost in the compaction conditions on the dryer condition, so the tenacity for liquefaction should also be noted.

Evaluation of effective use of dredged soil as containment dikes of a disposal pond in Japan
Katsuhide Nishizono; Yasuhiro Sega; Masaaki Katagiri; Yoichi Watabe
Geotechnical Research, 9, 3, 131, 140, Emerald, 01 Sep. 2022, [Peer-reviewed]
Scientific journal, An extra fill on a revetment was constructed by using mechanically dewatered clay (MDC) made from dredged material in the third area of the Shinmoji-Oki disposal pond (S-3), Japan, in 2011. Since MDC is an artificial material, its long-term stability has not been confirmed. To understand the long-term stability of the constructed revetment, mechanical tests, such as box shear tests, were conducted on block samples taken from two designated areas of the extra fill on the revetment over the 10 years since its construction (2011–2020). As a result, it was confirmed that the shear strength under certain overburden effective stress sufficiently satisfied the value assumed at the designing stage and the strength properties did not change much after 10 years, although the strength constants varied.

Centrifugal model tests of gravity revetment using artificial rock made of dredged clay as backfill material
Tatsuya Emori; Kazuhiko Ueno; Yoichi Watabe
Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 78, 2, I_547, I_552, Japan Society of Civil Engineers, 2022, [Peer-reviewed]
Scientific journal

Inspection analysis of consolidation settlement and lateral displacement for 5 kinds of ground improvement example by elasto-viscoplastic constitutive model
Kenta MIZUNO; Takashi TSUCHIDA; Masaki KOBAYASHI; Yoichi WATABE; Yoshiyuki MORIKAWA; Hideo HASHIZUME
Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 77, 2, I_403, I_408, Sep. 2021, [Peer-reviewed]
Japanese, Scientific journal

The urban restoration in Satozuka district, Sapporo due to 2018 Hokkaido eastern Iburi earthquake
Masato Sasaki; Ken Sushida; Hidefumi Sakurai; Shunzo Kawajiri; Yoichi Watabe
Journal of Japan Society of Civil Engineers, Ser. F4 (Construction and Management), 77, 2, I_70, I_89, Japan Society of Civil Engineers, 2021, [Peer-reviewed]
Scientific journal

Ground movements and damage in Satozuka district, Sapporo due to 2018 Hokkaido Eastern Iburi Earthquake
Yoichi Watabe; Satoshi Nishimura
Soils and Foundations, 60, 5, 1331, 1356, Elsevier BV, Oct. 2020, [Peer-reviewed], [Lead author]
Scientific journal

Experimental study on erodibility of cement/steelmaking-slag treated soils by means of small jet erodometer
Y. Watabe; S. Sassa
Scour and Erosion IX - Proceedings of the 9th International Conference on Scour and Erosion, ICSE 2018, 567, 574, 2019, [Peer-reviewed], [Lead author]
International conference proceedings

Mechanical characteristics of undisturbed coral gravel soils: The intergranular void ratio as a common governing parameter
Yoichi Watabe; Shinji Sassa; Takashi Kaneko; Yukio Nakata
Soils and Foundations, 57, 5, 760, 775, Oct. 2017, [Peer-reviewed], [Lead author]
English, Scientific journal

Accounting for carbon stocks in soils and measuring GHGs emission fluxes from soils: Do we have the necessary standards?
Antonio Bispo; Lizzi Andersen; Denis A. Angers; Martial Bernoux; Michel Brossard; Lauric Cécillon; Rob N.J. Comans; Joop Harmsen; Knut Jonassen; Frank Lamé; Caroline Lhuillery; Stanislav Maly; Edith Martin; Angus E. Mcelnea; Hiro Sakai; Yoichi Watabe; Thomas K. Eglin
Frontiers in Environmental Science, 5, Article 41, Frontiers Media S.A., 12 Jul. 2017, [Peer-reviewed]
English, Scientific journal

Studies on the cathodic protection characteristics in seabed soil and the cathodic protection design of the port steel structures in consideration of the soil resistivity
Shinji UTSUNO; Toru YAMAJI; Kazuhide YONAMINE; Yoshikazu AKIRA; Hiroyuki KOBAYASHI; Yoichi WATABE; Michio YOSHIDA; Yuichi MAEZONO; Yoshiyuki KAWASE; Shigeru MATSUMOTO
Journal of Japan Society of Civil Engineers, Ser. E2 (Materials and Concrete Structures), 73, 2, 220, 238, Japan Society of Civil Engineers, 2017, [Peer-reviewed]
Scientific journal

Method for reducing the risk of water leakage from the joints of water-shielding box-shaped steel sheet pile
Toshiyasu MIYOSHI; Tomohiro TANAKA; Takuzo KUZU; Naoya NAGAO; Yoichi WATABE
Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 73, 2, I_294, I_299, Japan Society of Civil Engineers, 2017, [Peer-reviewed]
Scientific journal

Experimental study of the in-situ microbial induced carbonate precipitation techniques applying for the restoration work in the world national heritage site Ichkeul in Tunisia
Toshiro HATA; Takaaki MIZUTANI; Yoichi WATABE
Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 73, 2, I_863, I_868, Japan Society of Civil Engineers, 2017, [Peer-reviewed]
Scientific journal

Soil parameters governing mechanical properties of coral gravel soils
Yoichi Watabe; Takashi Kaneko; Shinji Sassa
ICSMGE 2017 - 19th International Conference on Soil Mechanics and Geotechnical Engineering, 2017-September, 3071, 3074, 2017, [Peer-reviewed], [Lead author]
International conference proceedings

Quality evaluation of undisturbed sample taken from seabed in Tokyo Bay based on various strength tests
Takashi TSUCHIDA; Takatoshi NOGUCHI; Yoichi WATABE
Japanese Geotechnical Journal, 12, 1, 135, 149, The Japanese Geotechnical Society, 2017, [Peer-reviewed]
Scientific journal

Sedimentation History of Sandbars in Flood-Tidal Delta Evaluated by Seismic Method in Lake Tofutsu, Japan
Yoichi Watabe; Shinji Sassa
Journal of Coastal Research, 32, 6, 1389, 1401, Nov. 2016, [Peer-reviewed], [Lead author]
English, Scientific journal

Sediment stratigraphy observed by MASW survey along an array comprised of supralittoral, mediolittoral, and infralittoral zones
WATABE Yoichi; KANEKO Takashi; SASSA Shinji; HASHIMOTO Yuji; NAKAJO Sota
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 72, 2, I_1699, I_1704, Japan Society of Civil Engineers, 2016, [Peer-reviewed], [Lead author]
Japanese, The Okoshiki Coast in Uto City, Kumamoto Prefecture, Japan, is a beautiful sandy tidalflat with rhythmical variation of multi-bar-trough structure. To investigate the sediment stratigraphy, multi-channel analysis of surface waves (MASW) was applied to this sandflat; however, the conventional method using geophones was only applicable to exposed regions in supralittoral and mediolittoral zones. In this study, MASW array was extended from mediolittoral to infralittoral zones by using hydrophones instead of geophones. Sediment stratigraphy was successfully evaluated by using geophones in supralittoral and mediolittoral zones during exposed periods and using hydrophones in mediolittoral and infralittoral zones during submerged periods. In the MASW survey using hydrophones conducted on a boat, it must be noted that the shear wave velocity structure at shallower depth is influenced by the offset distance between the shot point and the nearest hydrophone.

Monitoring for sediment structure at artificial intertidal flats by means of MASW: applicability of hydrophones at submerged regions
Yoichi WATABE; Shinji SASSA; Takashi KANEKO; Yuji HASHIMOTO
Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 72, 2, I_449, I_454, Japan Society of Civil Engineers, 2016, [Peer-reviewed], [Lead author]
Japanese,  Temporal variation of soil properties of the reclaimed dredged soil and sand capping at an artificial intertidal flat has been monitored by means of multi-channel analysis of surface waves (MASW). MASW survey has been conducted using geophones during an exposure period; however, it cannot be continued when the survey array submerges even in the period of ebb-tide because of large consolidation settlement. In the present study, MASW survey using hydrophones is applied to the submerged region to continue monitoring the soil properties. The results obtained by MASW survey using hydrophones are similar to those obtained by MASW survey using geophones; however, there is a tendency that the sand capping is evaluated slightly thinner and the bottom boundary of the very soft soil layer is unclear in the MASW survey with hydrophones, because seismic attenuation in the soft soil layers is significant.

Modeling and Implementation of the Isotache Concept for Long-Term Consolidation Behavior
Yoichi Watabe; Serge Leroueil
International Journal of Geomechanics, 15, 5, Oct. 2015, [Peer-reviewed], [Lead author]
English, Scientific journal

Mechanical characteristics of reconstituted coral gravel soils with different fractions of finger-coral fragments and silt matrix
Yoichi Watabe; Shinji Sassa; Takashi Kaneko; Yukio Nakata
Soils and Foundations, 55, 5, 1233, 1242, Oct. 2015, [Peer-reviewed], [Lead author]
English, Scientific journal

Stability of Caisson‐type Breakwater’s Mound and Reinforcing Embankment against Tsunami
高橋英紀; 佐々真志; 森川嘉之; 渡部要一; 高野大樹
港湾空港技術研究所報告, 54, 2, 21-23,25-50, 50, 港湾空港技術研究所, Sep. 2015
Japanese

Importance of sedimentation process for formation of microfabric in clay deposit
Yoichi Watabe; Kunio Saitoh
Soils and Foundations, 55, 2, 276, 283, Apr. 2015, [Peer-reviewed], [Lead author]
English, Scientific journal

Temporal variation of sedimentary structure of dredged soil layer in an artificial intertidal flat: follow up research using MASW and its verification
Yoichi WATABE; Shinji SASSA; Takashi KANEKO; Kazuhiko UENO; Koichi YAMADA; Yuji HASHIMOTO
Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 71, 2, I_826, I_831, Japan Society of Civil Engineers, 2015, [Peer-reviewed], [Lead author]
Scientific journal

Effects of several particular soils on consistency limits
Masanori Tanaka; Yoichi Watabe; Miyoko Nakajima; Ryuzo Tomita
Proceedings of the International Offshore and Polar Engineering Conference, 2015-, 795, 801, International Society of Offshore and Polar Engineers, 2015
English, International conference proceedings

Development of a new small jet erodometer to measure erosion under atmospheric and submerged conditions
Y. Watabe; S. Sassa; T. Kaneko
Scour and Erosion - Proceedings of the 7th International Conference on Scour and Erosion, ICSE 2014, 657, 665, 2015, [Peer-reviewed], [Lead author]
International conference proceedings

A study on geotechnical risk management in the airport construction on the sea by design-build
Takatoshi NOGUCHI; Yoichi WATABE; Takashi TSUCHIDA
Journal of Japan Society of Civil Engineers, Ser. F4 (Construction and Management), 71, 1, 33, 43, Japan Society of Civil Engineers, 2015, [Peer-reviewed]
Scientific journal

Evaluation of consolidation settlement of the clayey ground including partial sand layers
Hiroshi SHINSHA; Hiroshi YONEYA; Changjin KO; Takahiro KUMAGAI; Yoichi WATABE
Japanese Geotechnical Journal, 10, 2, 173, 186, The Japanese Geotechnical Society, 2015, [Peer-reviewed]
Japanese, For clayey ground including partial sand layers, it is difficult to precisely predict consolidation settlement. The reason is the difficulties in grasping the distribution of partial sand layers and in calculating the settlement by FEM analysis considering the three-dimensional distribution of sand layers. In a clayey ground including partial sand layers, the deposit was improved by installing prefabricated vertical drains and applying vacuum pressure. The distribution of partial sand layers was investigated in detail using the penetration resistance records obtained during installing work of prefabricated vertical drains. The drains were installed by square arrangement of 1.8-m spacing into the ground. The identified three-dimensional distribution of partial sand layers was reflected to three-dimensional FEM analysis, and the influence of sand layers on the settlement was clarified. As a result, it was confirmed that the influence of partial sand layers on consolidation settlement is significant and the settlement can be predicted by the method proposed in this paper.

Proposal of cutoff seawalls in coastal areas required high safety against the strong earthquake:- Experimental and numerical studies against the level 2 class strong earthquake -
OKUDA Kazuhiro; TSUCHIDA Takashi; WATABE Yoichi; UENO Kazuhiko; KANEKO Takashi; MURAKAMI Hiroki
Japanese Geotechnical Journal, 10, 3, 343, 358, The Japanese Geotechnical Society, 2015, [Peer-reviewed]
Japanese, Experimental and numerical studies are made for investigation of structural safety of off-shore waste disposal facility of disaster wastes and removed soils contaminated by the radio-active cesium due to the accident of Fukushima Daiichi nuclear power plant. As the structural safety and the function of seawall and impervious structures must be maintained to prevent the leakage of contaminated water in wastes for a long period, the facility must be designed against the level 2 class strong earthquake. In the present study, stability of a gravity type seawall and the separated impervious structure made of double walls of steel pipe sheet piles between which are filled with artificial geo-materials are investigated. Deformation of seawall and impervious structure under the level 2 class strong earthquakes are studied by the centrifuge model test, large scale shaking table test and the numerical analysis. It was shown that the sufficient distance between the seawall and the impervious structure may keep the safety of impervious structure which must be protected from deformation. The results of shaking table tests and the numerical analysis showed that the deformations of proposed structure were within the allowable level in regard to the present construction standards.

New sampling method and mechanical property for undisturbed soil with coral gravel
KAWAI Hiroyasu; SONODA Shinichi; WATABE Yoichi; MATSUMOTO Shojiro; IKEDA Masato; TAKADA Makoto; KITAMURA Ryosuke
Japanese Geotechnical Journal, 10, 3, 415, 424, The Japanese Geotechnical Society, 2015, [Peer-reviewed]
Japanese, The coral reef which spreads along the coastal line of Nansei Islands, in Japan produces the problematic soil with coral gravel of which the matrix is silt. It has been well-known for geotechnical engineering practice that to sample the high-quality undisturbed soil with coral gravel is very difficult because some pieces of coral branch are contained in silt soil and consequently its density is not large. Therefore, the soil properties of in-situ soil used as design parameters have not been accurate.
In this paper a new sampling method which was performed to challenge the above problem in Amami-Ohshima, one of Nansei Islands is explained with the geological environment and the soil properties of undisturbed soil with coral gravel obtained from laboratory soil tests.

Mechanical properties of coral-silt composite soils evaluated on the basis of skeletal structure of coral gravels
Yoichi Watabe; Takashi Kaneko; Shinji Sassa
15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability, 547, 551, Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, 2015, [Peer-reviewed]
English, International conference proceedings

History of land reclamation using dredged soils at Tokyo Haneda Airport
Yoichi Watabe; Shinji Sassa
15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability, 1784, 1789, Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, 2015, [Peer-reviewed]
English, International conference proceedings

Safety assessment of an artificial intertidal flat using MASW technology
Yoichi Watabe; Shinji Sassa; Takashi Kaneko; Kazuhiko Ueno; Koichi Yamada
6th Japan-China Geotechnical Symposium, SJGS 2015, 30, 34, Japanese Geotechnical Society, 2015, [Peer-reviewed]
English, International conference proceedings

Description of partial sandy layers of dredged clay deposit using penetration resistance in installation of prefabricated vertical drains
Yoichi Watabe; Hiroshi Shinsha; Hiroshi Yoneya; Changjin Ko
Soils and Foundations, 54, 5, 1006, 1017, Oct. 2014, [Peer-reviewed]
English, Scientific journal

Role of suction in sandy beach habitats and the distributions of three amphipod and isopod species
Shinji Sassa; Soonbo Yang; Yoichi Watabe; Naoto Kajihara; Yoshitake Takada
Journal of Sea Research, 85, 336, 342, Jan. 2014, [Peer-reviewed]
English, Scientific journal

Ecological geotechnics: Role of waterfront geoenvironment as habitats in the activities of crabs, bivalves, and birds for biodiversity restoration
S. Sassa; Y. Watabe; S. Yang; T. Kuwae
Soils and Foundations, 53, 2, 246, 258, Apr. 2013, [Peer-reviewed]
English, Scientific journal

Experiment and examination about submerged mound made form mixture of dredged soil and converter slag on the soft ground
Koichi YAMADA; Takumi TSUJI; Yoichi WATABE; Taka-aki MIZUTANI; Yoshiyuki MORIKAWA; Akiyuki UKAI
Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 69, 2, I_1048, I_1053, Japan Society of Civil Engineers, 2013, [Peer-reviewed]
Scientific journal

Consolidation property of dredged soil mixed with discrete fiber
Hiroshi SHINSHA; Takahiro KUMAGAI; Yoichi WATABE
Japanese Geotechnical Journal, 8, 3, 403, 414, The Japanese Geotechnical Society, 2013, [Peer-reviewed]
Scientific journal

Simplified modelling of isotache concept for consolidation
Yoichi Watabe; Serge Leroueil
Springer Series in Geomechanics and Geoengineering, 139, 143, Springer Verlag, 2013
English, Scientific journal

Effects of crushed diatom microfossils content on physical properties of japanese clays
Masanori Tanaka; Yoichi Watabe; Ryuzo Tomita
Proceedings of the International Offshore and Polar Engineering Conference, 513, 517, 2013
English, International conference proceedings

Comparative study of long-term consolidation for subsoils under Kansai Airport and Pisa Tower
Y. Watabe; S. Sassa; K. Udaka
Challenges and Innovations in Geotechnics: Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, 1, 437, 440, 2013, [Peer-reviewed]
English, International conference proceedings

Verification of the Sedimentation History of the Sand Bars in the Entrance of Tofutsu Lake Evaluated by MASW
Yoichi WATABE; Shinji SASSA; Miyoko NAKAJIMA
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 69, 2, I_1411, I_1415, Japan Society of Civil Engineers, 2013, [Peer-reviewed]
Japanese, A significant development of sandbars can be seen at the entrance of Lake Tofutsu, one of the lagoons located along the Okhotsk Sea in Hokkaido, Japan. The authors have evaluated the sequential sedimentation history of the sand bars by means of MASW (Multi-channel Analysis of Surface Waves). The purpose of this study is to verify this sedimentation history through soil sampling and laboratory testing at some typical points along the arrays of MASW. Sampling method was modified to be suitable for low-cost soil investigation at tidal flats. The samples collected were examined in the laboratory to obtain the depth profiles of grain-size distribution and carbon 14 dating. The results obtained in this study are consistent with the sequential sedimentation history evaluated by MASW.

Site investigation for D-runway project at Tokyo Haneda Airport
Yoichi Watabe; Takatoshi Noguchi; Shinji Sassa
5th China-Japan Geotechnical Symposium, 456, 463, 2013
International conference proceedings

Development and verification of ecohabitat chart based on ecological geotechnics
S. Sassa; Y. Watabe; S. Yang
18th International Conference on Soil Mechanics and Geotechnical Engineering: Challenges and Innovations in Geotechnics, ICSMGE 2013, 4, 3069, 3072, 2013
International conference proceedings

Experimental study on vacuum consolidation sucking water through an intermediate sand layer
Hiroshi SHINSHA; Kenji MIYAMOTO; Yoichi WATABE
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 69, 2, I_970, I_975, Japan Society of Civil Engineers, 2013, [Peer-reviewed]
Japanese, Intermediate sand layers with high permeability often exist in the ground which has formed by disposing dredged soil. In the case of improving such a ground using the vacuum consolidation method, it is concerned that the consolidation effects would be decreased by sucking considerable seawater through intermediate sand layers. For a purpose to clarify an influence of such intermediate sand layer, two laboratory model tests were carried out. One was a vacuum consolidation test with water suction rate of 2ℓ/min per prefablicated drain and the other was a normal vacuum consolidation test without water supply from the intermediate sand layer. It was observed that the settlement curves of these two cases well agreed. Therefore, it was clarified that the water suction from the intermediate sand layer with its rate of 2ℓ/min does not significantly influence on the performance of vacuum consolidation system.

Seismic performance of caisson type quay wall with lightweight backfill
Yoichi Watabe; Shinichiro Imamura; Takashi Tsuchida
Indian Geotechnical Journal, 43, 2, 127, 136, 2013, [Peer-reviewed]
English, Scientific journal

Sedimentary stratigraphy of natural intertidal flats with various characteristics
Yoichi Watabe; Shinji Sassa
Soils and Foundations, 52, 3, 411, 429, Jun. 2012, [Peer-reviewed]
English, Scientific journal

Long-term consolidation behavior interpreted with isotache concept for worldwide clays
Yoichi Watabe; Kaoru Udaka; Yukio Nakatani; Serge Leroueil
Soils and Foundations, 52, 3, 449, 464, Jun. 2012, [Peer-reviewed]
English, Scientific journal

Use of cement-treated lightweight soils made from dredged clay
Yoichi Watabe; Takatoshi Noguchi; Yoshio Mitarai
Journal of ASTM International, 9, 4, Apr. 2012, [Peer-reviewed]
English, Scientific journal

Effects of Tide and River Discharge on Mud Transport on Intertidal Flat
F. Yamada; N. Kobayashi; Y. Shirakawa; Y. Watabe; S. Sassa; A. Tamaki
Journal of Waterway Port Coastal and Ocean Engineering-ASCE, 138, 2, 172, 180, Mar. 2012, [Peer-reviewed]
English, Scientific journal

Design of D-runway in Haneda Airport
Takatoshi NOGUCHI; Yoichi WATABE; Hiroyuki SUZUKI; Tsunehiro SAKAIYA; Koichiro KAKEHASHI; Katsutoshi OGURA; Kenta MIZUNO
Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering), 68, 1, 150, 162, Japan Society of Civil Engineers, 2012, [Peer-reviewed]
Scientific journal

Execution and maintenance of D-runway in Haneda Airport
Takatoshi NOGUCHI; Yoichi WATABE; Hiroyuki SUZUKI; Nobuyuki OKU; Ryuji YAMATOYA; Masaya WATANABE
Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering), 68, 2, 305, 320, Japan Society of Civil Engineers, 2012, [Peer-reviewed]
Scientific journal

Study on estimation of structures of natural marine clay deposits using a simple model of e - log p curves
Kaoru UDAKA; Takashi TSUCHIDA; Yoichi WATABE; Masanori TANAKA; Yohei IMAI
Japanese Geotechnical Journal, 7, 4, 527, 542, The Japanese Geotechnical Society, 2012, [Peer-reviewed]
Scientific journal

Research on the reclamation and consolidation of an artificial tidal flat filled with dredged clay
Kazuhiko UENO; Noriko KIKUHARA; Koichi YAMADA; Yoichi WATABE
PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN, 68, 2, I_1079, I_1084, Japan Society of Civil Engineers, 2012, [Peer-reviewed]
Japanese, An artificial tidal flat has been reclaimed with dredged marine clay in Port of Tokuyamakudamatsu. The artificial tidal flat was soft clay ground, so that reclamation and sand capping works were difficulty. Then, the ground will have consolidated for a long time after the construction. Therefore, we have been investigating into grounds of the artificial tidal flat from immediately after the construction at 2009. This research paper reports the reclaiming and sand capping cases and results of the field examination on the artificial tidal flat grounds and the consolidation analysis.

Life-prolongation for the new waste disposal facilities using the vacuum consolidation method
Tsuneo NAOI; Yoichi WATABE; Hiroshi SHINSHA; Masatoshi HIDATA; Shinichirou SHIRAGA
Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 68, 2, I_498, I_503, Japan Society of Civil Engineers, 2012, [Peer-reviewed]
Japanese, The new waste disposal site is the last place left in Tokyo bay which can dispose of municipal/industrial wastes, construction waste soil, dredged soil and so on carried from the Tokyos 23 wards. Therefore, a life-prolongation project for utilizing this area for a long period is on going from 2005 to the present. Its purpose is to increase a capacity of the disposal area by reducing the volume of disposed dredged soil by using the vacuum consolidation method. In this project, there were two geo-technical features. One was a necessity to evaluate the settlement considering the influence of the intermediate sand layers widely existing in a clayey layer. The other was a necessity to determine the vacuum consolidation period with ensuring the average consolidation degree of over 80% based on a comparison of the actual settlement with the predicted one. This paper describes about management methods of consolidation settlement, an intermediate sand layers distribution, the settlement properties and the volume reduction effect of clayey soil by using the vacuum consolidation method.

Long-term consolidation settlement prediction of d-runway in tokyo international airport
Kenta Mizuno; Yoichi Watabe; Masaki Kobayashi; Takatoshi Noguchi; Yasunori Aoki; Takanobu Yamamoto; Mitsuru Takahashi
Zairyo/Journal of the Society of Materials Science, Japan, 61, 1, 78, 84, Jan. 2012, [Peer-reviewed]
Japanese, Scientific journal

Use of Cement-Treated Lightweight Soils Made from Dredged Clay
Yoichi Watabe; Takatoshi Noguchi; Yoshio Mitarai
CONTAMINATED SEDIMENTS: RESTORATION OF AQUATIC ENVIRONMENT, VOL 5, 1554, 15, 31, 2012, [Peer-reviewed]
English, International conference proceedings

Site-investigation and geotechnical design of D-runway construction in Tokyo Haneda Airport
Yoichi Watabe; Takatoshi Noguchi
Soils and Foundations, 51, 6, 1003, 1018, Dec. 2011, [Peer-reviewed], [Lead author]
English, Scientific journal

Burrowing Criteria and Burrowing Mode Adjustment in Bivalves to Varying Geoenvironmental Conditions in Intertidal Flats and Beaches
Shinji Sassa; Yoichi Watabe; Soonbo Yang; Tomohiro Kuwae
PLoS ONE, 6, 9, Sep. 2011, [Peer-reviewed]
English, Scientific journal

Ten year follow-up study of airfoam-treated lightweight soil
Yoichi Watabe; Hiroyuki Saegusa; Hiroshi Shinsha; Takashi Tsuchida
Proceedings of the Institution of Civil Engineers: Ground Improvement, 164, 3, 189, 200, Aug. 2011, [Peer-reviewed]
English, Scientific journal

Hydraulic conductivity and compressibility of mixtures of Nagoya clay with sand or bentonite
Y. Watabe; K. Yamada; K. Saitoh
Géotechnique, 61, 3, 211, 219, Mar. 2011, [Peer-reviewed]
English, Scientific journal

Verification of 3-D visualization of ground at Tokyo International Airport
Takatoshi NOGUCHI; Masanori TANAKA; Yoichi WATABE; Saiichi SAKAJO; Tomofumi SADAMURA
Japanese Geotechnical Journal, 6, 1, 69, 79, The Japanese Geotechnical Society, 2011, [Peer-reviewed]
Scientific journal

Construction of impervious sea wall structure in the coastal disposal facilities with clayey water interception material
Hirokazu YAMAZAKI; Koichi YAMADA; Akira HADA; Akira MICHINAKA; Satoshi UMEDA; Yoichi WATABE
Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 67, 2, I_434, I_439, Japan Society of Civil Engineers, 2011, [Peer-reviewed]
Scientific journal

Burrowing-performance-based Analysis of Benthos Distributions in Natural and Artificial Tidal Flats
Soonbo YANG; Shinji SASSA; Yoichi WATABE; Hiroyuki IWAMOTO; Kota NAKASE
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 67, 2, I_986, I_990, Japan Society of Civil Engineers, 2011, [Peer-reviewed]
Scientific journal

Improvement of estimation accuracy of sandflat stratigraphy with intermediate soft sublayer -Combination use of MASW and microtremor array measurements
Yoichi WATABE; Shinji SASSA; Fumihiko YAMADA; Koichi HAYASHI
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 67, 2, I_1361, I_1365, Japan Society of Civil Engineers, 2011, [Peer-reviewed]
Scientific journal

Dynamic stability and optimal design of intertidal sandbars due to the feedback between sediment transport and suction dynamics effects
Shinji SASSA; Yoichi WATABE; Soonbo YANG; Kazuhiro SHIRAI
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 67, 2, I_1131, I_1135, Japan Society of Civil Engineers, 2011, [Peer-reviewed]

Stratigraphy of intertidal flats with various scales and soil types: Sandflats, mudflats, and subtropical intertidal flats
Yoichi Watabe; Shinji Sassa
Proceedings of the International Offshore and Polar Engineering Conference, 365, 372, 2011
International conference proceedings

Role of waterfront suction in the distribution of food organisms for coastal fish
Shinji SASSA; Soonbo YANG; Yoichi WATABE; Naoto KAJIHARA; Yoshitake TAKADA
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 66, 1, 1126, 1130, Japan Society of Civil Engineers, 2010, [Peer-reviewed]
Scientific journal

Thickness effects on long-term consolidation by means of inter-connected oedometers
Y. Watabe; S. Sassa; K. Udaka; T. Emura
Physical Modelling in Geotechnics - Proceedings of the 7th International Conference on Physical Modelling in Geotechnics 2010, ICPMG 2010, 1, 197, 202, 2010
International conference proceedings

Benthic habitat selection induced by optimal burrowing and geoenvironmental gradients
SASSA Shinji; WATABE Yoichi; YANG Soonbo
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 66, 1, 1096, 1100, Japan Society of Civil Engineers, 2010, [Peer-reviewed]
English, The present study aims at examining the processes of benthic habitat selection as induced by optimal burrowing and geoenvironnmental gradients. We utilized a newly developed eco-geoenvironment-water tank in order to clarify the response of benthos to a wide variety of geoenvironments involving both optimal and critical conditions, OP and CR, for burrowing of sand-bubbler crab, Scopimera globosa. The results indicate that the benthos placed in the OP swiftly started burrowing, by contrast, the benthos placed in the CR migrated toward the OP to burrow there. Furthermore, the predicted patch formation based on our proposed optimal-burrowing-model is found to be well consistent with what has been manifested in the field. These results demonstrate that the burrowing benthos actively selects the suitable geoenvironments for their burrowing, thereby generating patch formation. Hence, the present finding will alter the current perspective of habitat selection based on optimal-foraging-model and will facilitate a new horizon of ecohabitat management in the future.

Applicability of MASW Technology to Safety Assessment of Artificial Intertidal Flats
WATABE Yoichi; SASSA Shinji; HAYASHI Koichi; YAMADA Koichi
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 66, 1, 1406, 1410, Japan Society of Civil Engineers, 2010, [Peer-reviewed]
English, Most of the artificial intertidal flats are filled with dredged clay and have a sand capping. Immediately after the construction, because the dredged clay has not consolidated, a safety assessment system is strongly required to avoid a person who is caught in a soft clay layer at a place where sand capping is significantly thin. The authors have applied MASW method to various types of intertidal flats, and confirmed that the MASW is very useful method to efficiently survey the stratigraphy of intertidal flats. In this study, the MASW was applied to three intertidal flats: an artificial flat which was immediately after the filling; an artificial flat which was about ten years after the filling; and a natural muddy flat which has deposited over many years. Through these investigations, it was confirmed that MASW technology is useful to evaluate the safety of artificial intertidal flats.

Physical modelling for ecological geotechnics
S. Sassa; Y. Watabe
PHYSICAL MODELLING IN GEOTECHNICS, VOLS. 1 AND 2, 1483, 1488, 2010, [Peer-reviewed]
English, International conference proceedings

Foraging mode shift in varying environmental conditions by dunlin Calidris alpina
Tomohiro Kuwae; Eiichi Miyoshi; Shinji Sassa; Yoichi Watabe
Marine Ecology Progress Series, 406, 281, 289, 2010, [Peer-reviewed]
English, Scientific journal

Practical determination method for soil parameters adopted in the new performance based design code for port facilities in Japan
Yoichi Watabe; Masanori Tanaka; Yoshiaki Kikuchi
Soils and Foundations, 49, 6, 827, 839, Dec. 2009, [Peer-reviewed]
English, Scientific journal

Long-term properties of airfoam-treated lightweight soil made from dredged clay
Yoichi Watabe; Masanori Tanaka; Hiroyuki Saegusa; Hiroshi Shinsha; Takashi Tsuchida
Journal of ASTM International, 6, 4, Apr. 2009, [Peer-reviewed]
English, Scientific journal

真空圧載荷による中間土地盤の変形解析
金田一広; 渡部要一; 山崎浩之
応用力学論文集, 12, 363, 370, 2009, [Peer-reviewed]

Effects of specimen thickness and skeletal structure on consolidation behavior around consolidation yield stress
Y. Watabe; M. Tanaka; S. Sassa; M. Kobayashi; K. Udaka
Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering, 1, 696, 699, 2009
International conference proceedings

An effective investigation of tidal flat sedimentation by means of UAV and MASW
Yoichi WATABE; Shinji SASSA
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 65, 1, 1441, 1445, Japan Society of Civil Engineers, 2009, [Peer-reviewed]
English, Scientific journal, This study aims to develop a new technology in order to evaluate temporospatial geomorphology and outline of the sedimentation stratigraphy in a small intertidal flat. A small unmanned aerial vehicle (UAV) with a compact digital camera was applied to take aerial photographs in the intertidal flat. Because the water surface of the intertidal flat is tranquil, the waterline (water's edge) evaluated by aerial photograph taken from the UAV corresponds to a very precise contour of the intertidal flat. In addition, a geophysical exploration named as the multi-channel analysis of surface waves (MASW) was applied to investigate the sedimentation stratigraphy of the flat. The shear wave velocity structure obtained by MASW, corresponding to the stiffness distribution of the sediments, was consistent with the soil slices sampled by handy geo-slicer.

Spectrum analysis for morphological features in intertidal flats with various characteristics
Yoichi WATABE; Shinji SASSA; Koichi HAYASHI
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 65, 1, 1096, 1100, Japan Society of Civil Engineers, 2009, [Peer-reviewed]
English, Scientific journal, In this study, shear wave velocity structures of sandy flats, muddy flats, and subtropical flats were evaluated by means of multi-channel analysis of surface waves (MASW). Spectrum analysis along the cross-shore direction was carried out in order to quantitatively characterize the dominant wavelength for the variations of both shear wave velocity and morphological structures of intertidal flats with various scales and soil types. In the intertidal flats with multi bar-trough structure, dominant wavelengths in a range of 40 to 90 m were obtained, while in the muddy flat or huge-scale homogeneous sandy flat, any dominant wavelength was not obtained. In subtropical intertidal flats, the dominant wavelength was strongly influenced by prominent lime rock rather than the morphological surface variation.

Performance and mechanics of self-burial activities of bivalves, Japanese Littleneck
Shinji SASSA; Yoichi WATABE; Soonbo YANG
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 65, 1, 1116, 1120, Japan Society of Civil Engineers, 2009, [Peer-reviewed]
English, Scientific journal, We investigated in detail the performance and mechanics of self-burial activities of bivalves, Japanese Littleneck, from juvenile to adult, by utilizing our new approach encompassing ecology, geophysics and geotechnics. The observed speeds, angles and depths of the self-burial were all governed by the bed surface shear strength irrespective of the types of materials. The increase in the surface shear strength induced the mode shift from the vertical self-burial to inclined and/or partial self-burial, ultimately reaching the non-self-burial state. This self-burial mode shift can be consistently explained by the proposed conceptual model in view of required energy principle. There exists an optimal stage of growth, at which the bivalves can achieve the highest capabilities, below or above which the self-burial capabilities decrease continuously.

Interspecific comparison of burrowing capabilities of benthic fauna in tidal flats
Shinji SASSA; Yoichi WATABE; Soonbo YANG
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 65, 1, 1226, 1230, Japan Society of Civil Engineers, 2009, [Peer-reviewed]
English, Scientific journal, The paper describes an interspecific comparison of burrowing capabilities of benthic fauna in tidal flats. By utilizing our new approach in Ecological Geotehcnics, we simulated and varied surface shear strengths of bed materials, to which we observed the responses of six species of invertebrates that belong to Arthropoda, Mollusca, and Annelida. The results demonstrate that for each of the burrowing activities there exist optimal, transitional and critical surface shear strengths, which are found to differ considerably between species, body sizes and weights. We have constructed a chart by which to examine such difference in the burrowing capabilities in an integrated manner in light of the associated geophysical environments in the field. This chart provides fresh important insights into natural selection of habitats of benthic fauna in tidal flats.

Sedimentation history of the sand bars in the entrance of Tofutsu Lake evaluated by means of MASW
Yoichi WATABE; Shinji SASSA; Koichi HAYASHI; Koichi KOBAYASHI
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 65, 1, 661, 665, Japan Society of Civil Engineers, 2009, [Peer-reviewed]
English, Scientific journal, At the entrance of the Tofutsu Lake, which is one of the lagoons located along the Okhotsk Sea in Hokkaido, sand bars have been significantly developed. The objective of this study is to evaluate the sequential sedimentation history of the sand bars by means of MASW (Multi-channel Analysis of Surface Waves) technology. We found out that the sedimentation stratigraphy under the sand bars were significantly different from muddy to sandy, even though the sand bars apparently consisted of the same sandy material. From the shear wave velocity structure obtained in this study, we successfully restored the sequential sedimentation process. Also, the sedimentation history was consistent with an old aerial photograph and memories of local inhabitants.

Ecological geotechnics: Performance of benthos activities controlled by suction, voids, and shear strength in tidal flat soils
S. Sassa; Y. Watabe
Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering, 1, 316, 319, 2009, [Peer-reviewed]
English, International conference proceedings

Mechanism of vacuum consolidation using soil water coupled analysis and application
Kazuhiro KANEDA; Yoichi WATABE; Hiroyuki YAMAZAKI; Hiroshi SHINSHA; Takahiko SHIINA
Japanese Geotechnical Journal, 4, 3, 245, 258, The Japanese Geotechnical Society, 2009, [Peer-reviewed]
Japanese, Scientific journal, Soil- water coupled analysis of the vacuum consolidation were performed using SYS Cam Clay model, assuming the dredged soil, moisture content of which is high, to be the highly structured soils. The soil void is reduced with the decay of soil structure when the vacuum pressure is loaded under the low effective stress level. As for this consolidation method, the soils are improved by the increase of the effective stress along the soil deep area. Outside the improved area, a shear strain occurred from deep area. From generation of shear strain, a possibility of making the outer foundation heterogeneous from the improved region is being shown. In this paper, it is explained both field cases and numerical simulations. A field and simulation are well similar about settlement, surface shape and lateral displacement. And the possibility of the deformation prediction using FEM was shown.

Persistent sand bars explained by geodynamic effects
Shinji Sassa; Yoichi Watabe
Geophysical Research Letters, 36, Jan. 2009, [Peer-reviewed]
English, Scientific journal

Strain rate effect on long-term consolidation of Osaka bay clay
Yoichi Watabe; Kaoru Udaka; Yoshiyuki Morikawa
Soils and Foundations, 48, 4, 495, 509, Aug. 2008, [Peer-reviewed]
English, Scientific journal

Effects of friction and thickness on long-term consolidation behavior of Osaka bay clays
Yoichi Watabe; Kaoru Udaka; Masaki Kobayashi; Takechiho Tabata; Tsuyoshi Emura
Soils and Foundations, 48, 4, 547, 561, Aug. 2008, [Peer-reviewed]
English, Scientific journal

Application of MASW technology to identification of tidal flat stratigraphy and its geoenvironmental interpretation
Yoichi Watabe; Shinji Sassa
Marine Geology, 252, 3-4, 79, 88, Jul. 2008, [Peer-reviewed]
English, Scientific journal

Threshold, optimum and critical geoenvironmental conditions for burrowing activity of sand bubbler crab, Scopimera globosa
S Sassa; Y Watabe
Marine Ecology Progress Series, 354, 191, 199, Inter-Research Science Center, 07 Feb. 2008, [Peer-reviewed]
Scientific journal

Temporospatial assessment of tidal flat geomorphology by means of UAV
Yoichi WATABE; Shinji SASSA
Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 64, 1, 24, 29, Japan Society of Civil Engineers, 2008, [Peer-reviewed]
Scientific journal

Proposal of sealing geomaterial for waste disposal sites in coastal area
Kazuhiko UENO; Koichi YAMADA; Yoichi WATABE
Journal of Japan Society of Civil Engineers, Ser. G, 64, 2, 177, 186, Japan Society of Civil Engineers, 2008, [Peer-reviewed]
Scientific journal

Geotechnical investigation at the planning site of the D-runway of the Tokyo International Airport
Yoichi WATABE; Masanori TANAKA; Takatoshi NOGUCHI; Masafumi MIYATA
Journal of Japan Society of Civil Engineers, Ser. C, 64, 3, 585, 597, Japan Society of Civil Engineers, 2008, [Peer-reviewed]
Scientific journal

Role of waterfront geoenvironments in the relationships between birds, sediments and benthos
Shinji SASSA; Yoichi WATABE; Tomohiro KUWAE
Proceedings of Coastal Engineering, JSCE, 55, 1171, 1175, Japan Society of Civil Engineers, 2008, [Peer-reviewed]
Scientific journal

Origin of morphodynamic stability of intertidal sand bars
Shinji SASSA; Yoichi WATABE
Proceedings of Coastal Engineering, JSCE, 55, 1176, 1180, Japan Society of Civil Engineers, 2008, [Peer-reviewed]
Scientific journal

Mechanical Properties of Lightweight Treated Soil Cured in Water Pressure
Takashi Tsuchida; Yi Xin Tang; Yoichi Watabe
Soils and Foundations, 47, 4, 731, 748, Elsevier BV, Aug. 2007, [Peer-reviewed]
Scientific journal

Variability of physical and consolidation test results for relatively uniform clay samples retrieved from Osaka Bay
Yoichi Watabe; Yasunori Shiraishi; Tomohide Murakami; Masanori Tanaka
Soils and Foundations, 47, 4, 701, 716, Elsevier BV, Aug. 2007, [Peer-reviewed]
Scientific journal

New Design Method on Bearing Capacity of Rubble Mound of Composite Breakwater with Consideration of Deformation
Takashi Tsuchida; Yi Xin Tang; Yoichi Watabe; Katsumasa Ishikura
Soils and Foundations, 47, 2, 219, 235, Elsevier BV, Apr. 2007, [Peer-reviewed]
Scientific journal

Role of suction dynamics in evolution of intertidal sandy flats: Field evidence, experiments, and theoretical model
Shinji Sassa; Yoichi Watabe
Journal of Geophysical Research: Earth Surface, 112, 1, Blackwell Publishing Ltd, 24 Mar. 2007, [Peer-reviewed]
English, Scientific journal

3D-Visualization of Ground of New Runway at Haneda Airport
Masanori Tanaka; Yoichi Watabe; Masafumi Miyata; Saiichi Sakajo
Soils and Foundations, 47, 1, 131, 139, Elsevier BV, Feb. 2007, [Peer-reviewed]
Scientific journal

Long-term properties of air-foam treated lightweight soil placed in coastal areas
Yoichi WATABE; Hiroyuki SAEGUSA; Tomoyuki UEDA; Takashi TSUCHIDA; Yoshio MITARAI; Hiroshi SHINSHA
Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering), 63, 1, 237, 248, Japan Society of Civil Engineers, 2007, [Peer-reviewed]
Scientific journal

Practical determination method of soil parameters for performance based design
Yoichi WATABE; Tomoyuki UEDA; Hiroyuki SAEGUSA; Masanori TANAKA; Yoshiaki KIKUCHI
Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering), 63, 2, 553, 565, Japan Society of Civil Engineers, 2007, [Peer-reviewed]
Scientific journal

Field performance and advanced application of impermeable steel seawalls for confined disposal facilities in coastal areas
Yoichi WATABE; Masanori KINOSHITA; Koichi YAMADA; Takeshi OKI
Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering), 63, 3, 662, 676, Japan Society of Civil Engineers, 2007, [Peer-reviewed]
Scientific journal

An integrated methodology to evaluate the tidal flat geoenvironments and its application to natural and artificial muddy flats
Shinji SASSA; Yoichi WATABE; Yasuhiro KAWANO; Kenjiro NAKASHIMA; Hideki YOSHIDA
Proceedings of Civil Engineering in the Ocean, JSCE, 23, 507, 512, Japan Society of Civil Engineers, 2007, [Peer-reviewed]
Scientific journal

Mechanisms of water retention dynamics in intertidal sandy flats and beaches
Shinji SASSA; Yoichi WATABE; Hirokazu ISHII
Proceedings of Coastal Engineering, JSCE, 54, 1151, 1155, Japan Society of Civil Engineers, 2007, [Peer-reviewed]
Scientific journal

On the critical surface shear strength for Japanese littleneck clams
Shinji SASSA; Yoichi WATABE
Proceedings of Coastal Engineering, JSCE, 54, 1196, 1200, Japan Society of Civil Engineers, 2007, [Peer-reviewed]
Scientific journal

Sedimentary structures and their formation in an intertidal flat with multi-bar-trough developed in both cross-shore and along-shore directions
Yoichi WATABE; Shinji SASSA; Kenji KAWANO
Proceedings of Coastal Engineering, JSCE, 54, 1166, 1170, Japan Society of Civil Engineers, 2007, [Peer-reviewed]
Scientific journal

Characteristics and countermeasures for the deterioration of Air-foam treated lightweight soil
Yoichi WATABE; Hiroyuki SAEGUSA; Tomoyuki UEDA; Takahiko SHIINA; Yasunori SHIRAISHI; Tomohide MURAKAMI
Japanese Geotechnical Journal, 2, 4, 311, 318, The Japanese Geotechnical Society, 2007, [Peer-reviewed]
Scientific journal

New constitutive equation of clay and the prediction of horizontal deformations of large scale embankments
Kenta MIZUNO; Takashi TSUCHIDA; Masaki KOBAYASHI; Yoichi WATABE
Journal of Japan Society of Civil Engineers, Ser. C, 63, 4, 936, 953, Japan Society of Civil Engineers, 2007, [Peer-reviewed]
Scientific journal

Acceleration of consolidation of bottom mud by wave action
KUMAGAI Takahiro; TSUCHIDA Takashi; OHTSUBO Masami; WATABE Yoichi; GOMYO Michio; SHIOTA Koji
Japanese Geotechnical Journal, 2, 3, 223, 235, The Japanese Geotechnical Society, 2007
Japanese, In the case where soft bottom mud with high water content over the liquid limit is fluidized by the pressure induced by waves, cracks are generated in the surface of the mud. The cracks develop under the action of tensile stress and shear stress caused by the rotation of principal stress in the periodic motion of waves. It is found that the dredged mud, which contains the smectite as clay mineral, fails developing definite deep cracks so that ductile mass of clay can be retained. The effect of the cracks on the acceleration of consolidation of the mud is reproduced and evaluated by a numerical analysis and experiment of self-weight consolidation with the placement of vertical drains. The mechanism of the acceleration of consolidation of the mud by wave action is elucidated through experimental and numerical studies.

Probabilistic modelling of saturated/unsaturated hydraulic conductivity for compacted glacial tills
Y. Watabe; J.-P. LeBihan; S. Leroueil
Géotechnique, 56, 4, 273, 284, Thomas Telford Ltd., May 2006, [Lead author]
Scientific journal, A probabilistic model including some previous probabilistic studies is proposed to evaluate hydraulic conductivity from pore entrance size distribution. The model considers multi-pores in series of paths through capillary networks in the soil fabric. The average number of connected pores is a representative value of the fabric, greater than two but not too large. The hydraulic conductivity of three glacial tills from northern Québec with different grain-size distributions has been examined by horizontal permeability tests in saturated conditions, and suction tests with vertical permeability measurement in unsaturated conditions. The hydraulic conductivity is strongly influenced by compaction conditions corresponding to different microfabrics. The model is applicable not only in saturated conditions but also in unsaturated conditions with different microfabrics.

Study on consolidation characteristics of clayey soil in the intertidal zone
Takahiro Kumagai; Masaki Ueda; Katsuya Ikeno; Yoichi Watabe; Shinji Sassa
Proceedings of Coastal Engineering, JSCE, 53, 436, 440, Japan Society of Civil Engineers, 2006, [Peer-reviewed]
Scientific journal

Clarification of the critical phenomenon and suitable sediment environment for the habitation of tidal flat benthic organisms
Shinji Sassa; Yoichi Watabe
Proceedings of Coastal Engineering, JSCE, 53, 1061, 1065, Japan Society of Civil Engineers, 2006, [Peer-reviewed]
Scientific journal

Calculation method for expected deformation of breakwater mound based on results of large-scale hydraulic model experiments and examples of its application
Yoichi Watabe, Kenichiro Shimosako, Takeo Asanuma, Masayoshi Inagaki, Taro Isayama
Proceedings of Coastal Engineering, JSCE, 53, 821, 825, Japan Society of Civil Engineers, 2006, [Peer-reviewed]
Scientific journal

Geophysical evaluation of tidal flat sedimentary structures and their formation factors -Sandy, muddy, and sand-mud layered flats-
Yoichi Watabe; Shinji Sassa
Proceedings of Coastal Engineering, JSCE, 53, 1236, 1240, Japan Society of Civil Engineers, 2006, [Peer-reviewed]
Scientific journal

ノルウェー・オンソイ粘土の工学的性質
田中政典; 渡部要一; 亀井健史; 冨田龍三
地盤と建設, 24, 1, 35, 42, 2006, [Peer-reviewed]
Scientific journal

粘土の強度増加に関する考察と柳井粘土の土質調査結果による検証
鈴木耕司; 田中洋輔; 安原一哉; 渡部要一
第50回地盤工学シンポジウム論文集, 137, 142, 2005, [Peer-reviewed]

Analysis method for behavior of seabed mud under wave action
Takashi Tsuchida; Takahiro Kumagai; Katsuya Ikeno; Yoichi Watabe; Michio Gomyo
Proceedings of Coastal Engineering, JSCE, 52, 451, 455, Japan Society of Civil Engineers, 2005, [Peer-reviewed]
Scientific journal

Suction dynamics and its role in the sediment environment of sandy tidal flats
Shinji Sassa; Yoichi Watabe
Proceedings of Coastal Engineering, JSCE, 52, 981, 985, Japan Society of Civil Engineers, 2005, [Peer-reviewed]
Scientific journal

Ageing Effects on Consolidation Properties—Based on the Site Investigation of Osaka Pleistocene Clays—
Hiroyuki Tanaka; Min-Soo Kang; Yoichi Watabe
Soils and Foundations, 44, 6, 39, 51, Elsevier BV, Dec. 2004
Scientific journal

One-Dimensional Compression of Air-Foam Treated Lightweight Geo-Material in Microscopic Point of View
Yoichi Watabe; Yasunari Itou; Min-Soo Kang; Takashi Tsuchida
Soils and Foundations, 44, 6, 53, 67, Dec. 2004, [Lead author]
Scientific journal

Field performance test on the joint of steel pipe sheet piles using clay material as a hydraulic barrier.
Ueda Masaki; Ino Hitoshi; Yamada Koichi; Yoshino Hisayoshi; Watabe Yoichi
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 2295, 2296, The Japanese Geotechnical Society, 2004
鋼管矢板継手部に土質系変形追随遮水材を用いた場合について,実海域で施工築造した鋼管矢板壁試験体により遮水性能確認試験を行った。試験の概要と現在までに得られた遮水性能について報告する。 今回の試験結果より,管理型廃棄物処分場の遮水壁に求められる遮水性能が得られていることが確認された。

Effect of piling in water interception base of the costal disposal site
Fukuda Kenjiro; Ueda Masaki; Watabe Yoichi; Sugihara Hiroaki
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 2267, 2268, The Japanese Geotechnical Society, 2004
底面遮水基盤の存在しない海面管理型廃棄物処分場の建設の際には、底面に遮水基盤を構築し廃棄物を投入しなければならないという構造上の基準が定められている。本論文は、人工的に構築した粘性土の遮水基盤上に廃棄物が投入され、処分場が廃止された後に跡地利用として構造物を建築する際に、打設する基礎杭が人工的に構築した遮水基盤の遮水性能に及ぼす影響について確認した実験の報告である。実験は、1/25、1/5スケールの遮水基盤を実験土槽に作製し、模型杭打設前後での透水量を計測して遮水係数の算出を行ない杭打設による影響を調べた。

Field performance test on the welded joint of sheet piles as a hydraulic barrier
Ikeda Masahiro; Kita Hiroshi; Watabe Yoichi
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 2291, 2292, The Japanese Geotechnical Society, 2004
遮水性能の向上を目的とし、継手部に溶接を用いたBOX型鋼矢板について、実海域で施工築造したBOX型鋼矢板壁試験体により遮水性能確認試験を行った。試験の概要と現在までに得られた遮水性能について報告する。今回の試験結果より、管理型廃棄物処分場の遮水壁に求められる遮水性能が得られていることが確認された。

Field performance test of steel pipe sheet pile joints filled with asphalt compound as a hydraulic barrier
Kinoshita Masanori; Kobayashi Shigeo; Seo Akira; Watabe Yoichi
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 2293, 2294, The Japanese Geotechnical Society, 2004
遮水性能向上を目的とし、あらかじめアスファルトを充填した鋼管矢板継手について,実海域で施工築造した鋼管矢板壁試験体により遮水性能確認試験を行った。試験の概要と現在までに得られた遮水性能について報告する。今回の試験結果より管理型廃棄物処分場の遮水壁に求められる遮水性能が得られていることが確認された。

Experimental evaluation on cutoff performance of sheet pile wall spreaded the swelled sealant on its joints at sea
oki takeshi; kinoshita masanori; ikeda masahiro; watabe youichi
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 2287, 2288, The Japanese Geotechnical Society, 2004
Field performance test on sheet pile joints sealed with an expanding sealant as a hydraulic barrier

Field performance test on sheet pile joints with a pocket sealed with sealant/expanding rubber as a hydraulic barrier
Oka Yoshitake; Oki Takeshi; Ozumi Shouzou; Watabe Yoichi
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 2285, 2286, The Japanese Geotechnical Society, 2004
遮水性能向上を目的とした継手に空隙部を有する遮水用鋼矢板について,実海域で施工築造した鋼矢板壁試験体により遮水性能確認試験を行った。試験の概要と現在までに得られた遮水性能について報告する。今回の試験結果より,管理型廃棄物処分場の遮水壁に求められる遮水性能が得られていることが確認された。

Field performance tests on hydraulic barrier methods for coastal waste reclamation sites
Watabe Yoichi; Yamada Koichi; Yoshino Hisayoshi; Torizaki Keiichi; Oki Takeshi; Kita Hiroshi
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 2297, 2298, The Japanese Geotechnical Society, 2004
海面処分場の鉛直遮水工の開発・提案が進められてきたが,これまでは,室内における要素レベルでの遮水性能の評価が多かった.しかし,鉛直遮水工の多くは,陸上に比べて難しい海上での施工となることから,実海域における施工性ならびに遮水性能の評価は,工法の信頼性を評価する上で重要である.本研究では,鋼(管)矢板による遮水壁を構築するために,膨潤性遮水材,膨潤性ゴム,粘土系遮水材,アスファルト,モルタル,溶接等を組み合わせた新しい工法について,施工性と遮水性能を評価するために実海域での実証実験を行った.本報では,実海域実証実験の概要について示し,今後の成果の活用方法などについて取りまとめる.

Field performance test of steel pipe sheet pile joints using a rubber plate filled with mortar as a hydraulic barrier
Kobayashi Shigeo; Oka Yushitake; Kita Hiroshi; Kakimoto Ryuji; Watabe Yoichi
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 2289, 2290, The Japanese Geotechnical Society, 2004
遮水性能向上を目指した改良継手(漏洩防止ゴム板付き継手)を持つ鋼管矢板について,実海域で施工築造した試験体により遮水性能確認試験を行った。試験の概要と現在までに得られた遮水性能について報告する。今回の試験結果より本工法について管理型廃棄物処分場の遮水壁に求められる遮水性能が得られていることが確認された。

Report of the site investigations on Pisa clays (part II)
Shiina Takahiko; Tanaka Masanori; Watabe Yoichi; Shiraishi Yasunori; Murakami Tomohide
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 151, 152, The Japanese Geotechnical Society, 2004
2003年9月にイタリアのピサの斜塔において、日・伊二国間国際共同研究による地盤調査を実施した。この調査において、原位置試験として電気式静的コーン貫入試験を実施し、イタリア式と日本式のサンプリングによって持ち帰った試料について、各種物理試験および室内ベーンせん断試験、残留有効応力の測定、一軸圧縮試験、定ひずみ速度載荷による圧密試験といった力学試験を実施した。本論文はそれらの試験結果から、ピサ粘土の工学的特性について報告するものである。

Report of the site investigations on Pisa clays (part I)
Murakami Tomohide; Watabe Yoichi; Tanaka Masanori; Shiina Takahiko; Shiraishi Yasunori
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 149, 150, The Japanese Geotechnical Society, 2004
2003年9月にイタリアのPisa(ピサ)の斜塔で日・伊二国間国際共同研究による地盤調査を実施した。本調査では、イタリア式(シェルビーチューブサンプラーとオスターバーグ式サンプラー)と日本式(固定ピストン式シンウォールサンプラー)のボーリング・サンプリング、電気式静的コーン貫入試験(CPTFとCPTU)、ダイラトメータ試験を実施した。本論文は、地盤調査の概要、サウンディング結果及び採取試料の各種物理試験の結果を報告するものである。

Consolidation behavior according to different loading periods near the overburden pressure.
Nosaka Tomomasa; Tabata Takechiho; Watabe Yoichi; Udaka Kaoru; Tanaka Hiroyuki
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 217, 218, The Japanese Geotechnical Society, 2004
大阪湾洪積粘土は、地史的にみても現在の土被り圧よりも大きな圧力を受けていないのにも拘わらず過圧密的な圧密特性を有し、量的には無視できないほどに顕著な時間依存性沈下が継続していることが報告されている。 本研究は、不攪乱の大阪湾洪積粘土を用いて、定ひずみ速度圧密試験中に原位置での土被り圧付近で荷重制御によるクリープ試験を行い、クリープ期間の長さがその後の圧縮挙動や圧密特性に与える影響について検討した。 既往の研究によると、再構成試料に関しては、クリープ期間が長いほど圧密降伏応力が大きくなることが報告されている。今回実施した不攪乱試料でも、これと矛盾しない結果が得られた。

On the results of the in-situ soundings for a waste disposal landfill site.
Shiraishi Yasunori; Watabe Yoichi; Tanaka Masanori; Murakami Tomohide; Shiina Takahiko
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 2197, 2198, The Japanese Geotechnical Society, 2004
電気式静的コーン貫入試験(CPT)とダイラトメーター試験(DMT)により廃棄物埋立地盤の原位置調査を行った。調査地点の土層構成は廃棄物埋立地盤が約9m、以深は遮水層を成す粘性土が堆積しており、既存のボーリング調査位置の近傍で原位置試験を実施し、砂地盤、粘性土地盤での原位置試験結果と比較して廃棄物埋立地盤の特性を検討した。検討の結果、廃棄物埋立地盤におけるCPT、DMTの試験結果は調査地点によりバラツキを生じたが、調査地点の廃棄物埋立地盤は砂地盤と同程度の透水性があること、DMTによる水平応力インデックス(KD値)が粘性土と比較して小さいためK0が小さい地盤であることが確認された。

Thickness Effect on the Consolidation Characteristics of Osaka Bay Pleistocene Clay
Udaka Kaoru; Tabata Takechiho; Watabe Yoichi; Tanaka Hiroyuki; Nosaka Tomomasa
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 907, 908, The Japanese Geotechnical Society, 2004
近年、大規模な埋立て事業が行われるようになり、構造が高位な大阪湾洪積粘土の圧密特性に関する研究が盛んに行われている。 本報告では、不攪乱の大阪湾洪積粘土に対し、圧密供試体内部の挙動を確認する目的で分割型圧密試験装置を使用し、圧密降伏応力付近に載荷した際に層厚の違いが圧密特性に及ぼす影響について検討した。特に、室内試験結果から厚さ数m以上を対象とする原位置における圧縮及び透水現象を評価することを目的として、最大層厚20cm(2cm×10連結)までの試験を実施し、(1)層厚が異なることによる沈下挙動への影響(2)一般的な定ひずみ速度圧密試験から得られる透水係数との相違について検討した。

Mix Proportion Design and the Applicable Soil of the Light-weight Treated Soil with Air Foam Based on Execution Results(Part 2)-In the Case of the Fines-
Shinsha Hiroshi; Watabe Yoichi; Aikawa Seijiro; Taniguchi Toshihisa
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 751, 752, The Japanese Geotechnical Society, 2004
港湾・空港において、気泡混合処理土の施工が数多く実施されている。気泡混合処理土は原料土の含水比を調整して調整泥土を作製し、次に固化材と事前発泡させた気泡を混合して作製するものである。 本文は、こうした施工事例の中から、原料土が細粒土系の設計配合について整理し、考察したものである。その結果、(1)調整泥土の含水比は液性限界の約2.8倍に調整している事例が多いこと、(2)設計強度の確保においては、気泡混合処理土内の水量と気泡量を加えた間隙量が重要な要因の1つであること、(3)設計強度が200kN/m2以上の確保において、固化材添加量は約80~150kg/m3の範囲にあること、などが明らかとなった。

Magnification of SEM observation for clay samples
Takemura Tomoko; Watabe Yoichi
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 295, 296, The Japanese Geotechnical Society, 2004
粘土の微視的構造に関する研究において,近年,電子顕微鏡(SEM)による画像観察が活用されるようになった.しかし,高倍率で特定の対象物を観察したSEM画像では,その土の微視的な構造全体を代表しているとは言い難い.本研究では,大阪湾の海底(深度約20mと105m)から採取した(それぞれの長さ0.8mのサンプラー1本分ずつ)乱さない試料について,長さ25mmにつき8ヶ所ずつ計256ヶ所,倍率500~5000の4画像ずつ合計1024画像をSEMによって観察し,Scion Imageを用いて画像解析を行った.Scion Imageでは画像の濃さを256階調で表し,あるしきい値を設定して二値化することによって白黒の比率を求める.各観察倍率での白黒の比率の変化をばらつきを考慮して求め,対象とした粘土の代表的な構造を観察する場合の倍率の上限について考察した.

Dynamic Centrifuge Model Tests on Earthquake Resistance of Sheet Pile Quay Wall with Lightweight Backfill
Imamura Shinichiro; Kato Shigeyuki; Yamamura Kazuhiro; Kotake Nozomu; Watabe Yoichi
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 1635, 1636, The Japanese Geotechnical Society, 2004
本報告では、比較的密な砂地盤を対象に設計仕様の異なる2つの控え矢板式岸壁モデルによる遠心模型振動実験を実施し,軽量土の改良幅の違いによる矢板の変形,変位の低減効果と地震時安定性に及ぼす影響について検討した.その結果、地震に伴う矢板の応力、タイロッドの軸力は改良幅を大きくするほど,未改良に比べ軸力が確実に低減した.しかし,モデル2では控え矢板の剛性,根入れ長さが大きいため,矢板の応力や変位について明確な抑制効果がみられず、軽量土よりもむしろ、控えの根入れ長の効果が上回る結果となった.また、護岸背面の土圧は、分割法による土圧との対応が比較的良く、分割法による土圧式の妥当性を検証することができた。

Simulation of Centrifuge Model Tests on Quey Wall Backfilled by Light Weight Treated Soil
Kato Shigeyuki; Imamura Shinichiro; Miki Takayuki; Aikawa Seijiro; Watabe Yoichi
Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 1637, 1638, The Japanese Geotechnical Society, 2004
本報告では、筆者らが過去に実施した軽量混合処理土を裏込めに用いた重力式岸壁モデル(ケーソン高さ10m、幅7m)による遠心模型振動実験の結果について、FLIP解析によるシミュレーションを行った.実験は比較的密な砂地盤を対象に未改良を含め3ケース実施し、改良ケースではケーソン背面の改良幅を5m、10m(深さ5m一定)とした2ケースである。解析の結果、ケーソンの応答加速度、残留水平変位および位相について、各ケースともに実験結果と良好な一致し、遠心模型実験の結果をある程度の精度で再現することができた。よって、FLIP解析は、実測の物性値や適切なパラメータの設定により,ケーソン護岸の地震時応答予測の有用なツールとして期待できる。

K0-Consolidation in a Triaxial Cell and Evaluation of In-Situ K0 for Marine Clays with Various Characteristics
Yoichi Watabe; Masanori Tanaka; Hiroyuki Tanaka; Takashi Tsuchida
Soils and Foundations, 43, 1, 1, 20, Elsevier BV, Feb. 2003, [Lead author]
Scientific journal

混成防波堤におけるマウンドの支持力破壊に関する大規模水理模型実験
下迫 健一郎; 土田 孝; 増田 慎太郎; 渡部 要一; 藤井 敦
海洋開発論文集, 19, 499, 504, Japan Society of Civil Engineers, 2003
Japanese, Hydraulic model experiments on the stability of rubble mound foundation of composite breakwaters against wave action were conducted in a large wave flume, where the failures of rubble mound were reproduced. Sliding of the caisson was also occurred by the decrease of friction coefficient due to the settlement of rubble mound even the initial sliding safety factor is larger than 1.2. Numerical calculations of expected settlement due to mound failure using Monte Carlo simulation were also conducted in order to compare the experimental results. Calculated settlement was larger than experimental one because the elastic deformation of rubble mound foundation was not taken into account in the calculation.

変形追随遮水材料を用いた管理型廃棄物海面処分場の遮水工法に関する実海域実証実験
山田 耕一; 鵜飼 亮行; 伊野 同; 土田 孝; 渡部 要一
海洋開発論文集, 19, 177, 182, Japan Society of Civil Engineers, 2003
Japanese, In recent year, the capacity of the disposal space of waste is running short. Accordingly, construction of new disposing site is needed.
The standard of impervious structure about a disposal site was defined by the law 1999. However, with the past technology about impervious sea wall, it is very difficult to construct this type of structure meeting this law. Then, we proposed new structure and material about impervious sea wall, which maintains the performance of water interception over long period. This research paper reports the result of the field experiment about impervioussea wall structure with clayey water interception material.

Proposal of mixture design of highly impermeable geomaterials for the use of costal waste disposal sites
Kimura Makoto; Imai Goro; Ueno Kazuhiko; Tsuchida Takashi; Watabe Yoichi
Proceedings of the Japan National Conference on Geotechnical Engineering, 38, 2417, 2418, The Japanese Geotechnical Society, 2003
近年,廃棄物処分場用地を陸域に確保することが困難になっており,海面埋立型の廃棄物処分場に期待が寄せられている.そこで海域に建設される管理型廃棄物処分場の底面遮水に着目し,土質材料を用いて廃棄物荷重による圧密に伴う止水性を実験的に検討した.配合設計の確立を困難にしている原因は,配合ごとに異なるe-logk関係が存在するというその関係の一般性の欠如にある.本研究では正規化間隙比によって透水係数との配合によらない一義的な関係(e/eL-logk)を得た.その関係を用いて,現場の初期応力状態に基づく簡易的な配合設計方法を構築した.

General expression of compression behavior of sediments treated with cement
Fukue Masaharu; Watabe Yoichi
Proceedings of the Japan National Conference on Geotechnical Engineering, 38, 241, 242, The Japanese Geotechnical Society, 2003
貧配合セメント処理土の圧密試験結果について、土のセメンテーションという観点から、その状態式を考える。セメント処理土は時間とともに硬化するので、その硬化の程度はセメンテーションと見なすことができる。つまり、セメンテーション硬化は養生期間に依存する。本研究では、このようなセメンテーションを有する供試体の圧縮曲線がつぎの状態式で表せることを示す。(1+ ë) p =γs z ここに、ë は平均間隙比、 pは有効圧力、γsは定数(土粒子の水中単位体積重量)、zは変数(深さ)である。ここで、ëおよびpはzの関数で表せる。

Influence of sand fraction on the compressibility and hydraulic conductivity of clayey soil
Ueno Kazuhiko; Watabe Yoichi; Saitoh Kunio; Tsuchida Takashi; Yamada Koichi
Proceedings of the Japan National Conference on Geotechnical Engineering, 38, 2419, 2420, The Japanese Geotechnical Society, 2003
Some influences of sand fraction on the hydraulic conductivity and compressibility were examined. The followings are derived as conclusions: if the sandy particles do not make a skeletal structure and each particle independents in the clay matrix, increasing sand fraction contribute to decrease the compressibility, but does not affect on the hydraulic conductivity, under the same overburden stress. In this study, some evidence of sandy skeletal structure was observed for the specimens, whose clay fraction (less than 0.005mm) and sand fraction (larger than 0.075mm) are smaller than 16% and larger than 70%, respectively.

Microscopic observations of air foam treated soil during 1-D compression
Itou Yasunari; Watabe Yoichi
Proceedings of the Japan National Conference on Geotechnical Engineering, 38, 821, 822, The Japanese Geotechnical Society, 2003
軽量混合処理土に関する研究は,密度管理や強度特性を扱うものが多い.しかし,軽量混合処理土の利用が検討されている軟弱地盤上の大規模高盛土埋立や,軽量混合処理土が打設された地盤における土地利用形態の変更等により,従来は考慮していなかった自重圧縮等による変形特性に関する検討も重要になる.そこで,本研究では,一次元圧縮される気泡混合処理土の内部構造の変化を3種類の顕微鏡を用いて観察した.観察画像の定量化を図り,その結果をポロシメータにより計測された間隙径分布とともに考慮することによって一次元圧縮に伴う気泡混合処理土の内部構造の変化を微視的な視点から定量的に評価することを試みた.

Evaluation of 1-D compression for air foam treated soil from microscopic point of view
Watabe Yoichi; Itou Yasunari
Proceedings of the Japan National Conference on Geotechnical Engineering, 38, 823, 824, The Japanese Geotechnical Society, 2003
One-dimensional compression behavior of the air-foam treated soil was investigated in microscopic point of view. The test results are discussed with microscopic observations with three kinds of apparatuses (Optical CCD, SEM and Laser) and mercury intrusion porosimetory. The e – log p curves of the air foam treated lightweight geo-material, which is similar to that of a structured soil, can be nicely explained in consideration of microscopic observations. Visible pores corresponding to the ″air-form″ decrease and disappear before ″intra-micro″ and ″inter-macro″ pores significantly decrease.

Undrained Shear Strength of Pleistocene Clay in Osaka Bay
Yoichi Watabe; Takashi Tsuchida; Kakuichiro Adachi
Journal of Geotechnical and Geoenvironmental Engineering, 128, 3, 216, 226, American Society of Civil Engineers (ASCE), Mar. 2002, [Lead author]
Scientific journal

粘土係遮水材料における微視構造と透水係数の関係
渡部要一; 土田 孝; 斎藤邦夫; 山田耕一; 上野一彦
第47回地盤工学シンポジウム論文集, 381, 388, 2002, [Peer-reviewed]

PROPOSAL OF A NEW IMPERVIOUS SEA WALL STRUCTURE IN A COASTAL DISPOSAL SITE WITH THE DEFORMATION FOLLOWING MATERIAL
YAMADA Koichi; UENO Kazuhiko; HADA Akira; TSUCHIDA Takashi; WATABE Yoichi
Doboku Gakkai Ronbunshuu B, 18, 77, 82, Japan Society of Civil Engineers, 2002
The standard of impervious structure were specified with the law about a disposal site revisedin 1999. However, with the past material and method, it cannot respond enough. Then, we are grappling with development of a impervious material and a impervious method and a impervious structure newer than several year before. This paper explains the new deformation following impervious material and the new impervious structure.

Development of the impervious method to follow a deformation in a coastal disposal site (part1)
Ueno Kazuhiko; Yamada Kouichi; Hada Akira; Tsuchida Takashi; Watabe Yoichi; Nagae Yasushi; Kuwahara Joji
Proceedings of the Japan National Conference on Geotechnical Engineering, 37, 2427, 2428, The Japanese Geotechnical Society, 2002

Development of the impervious method to follow a deformation in a coastal disposal site (part2)
Hada A.; Yamada K.; Ueno K.; Tsuchida T.; Watabe Y.; Abe K.
Proceedings of the Japan National Conference on Geotechnical Engineering, 37, 2429, 2430, The Japanese Geotechnical Society, 2002
Symposium

Comparative Study on Undrained Shear Strength of Osaka Bay Pleistocene Clay Determined by Several Kinds of Laboratory Test
Yoichi Watabe; Takashi Tsuchida
Soils and Foundations, 41, 5, 47, 59, Oct. 2001, [Lead author]
Scientific journal

Comparison of Mechanical Behavior of Two Overconsolidated Clays: Yamashita and Louiseville Clays
Hiroyuki Tanaka; Dinesh R. Shiwakoti; Osamu Mishima; Yoichi Watabe; Masanori Tanaka
Soils and Foundations, 41, 4, 73, 87, Elsevier BV, Aug. 2001
Scientific journal

Influence of Stress Release on Sample Quality of Pleistocene Clay Collected from Large Depth in Osaka Bay
Yoichi Watabe; Takashi Tsuchida
Soils and Foundations, 41, 4, 17, 24, Elsevier BV, Aug. 2001, [Lead author]
Scientific journal

Mechanical properties of dredged soil treated with low quantity of cement
Yoichi Watabe; Takehide Furuno; Takashi Tsuchida
Journal of Japan Society of Civil Engineers, 694, III-57, 331, 342, 2001, [Peer-reviewed]

Influence of compaction conditions on pore-size distribution and saturated hydraulic conductivity of a glacial till
Y. Watabe; S. Leroueil; J.-P. Le Bihan
Canadian Geotechnical Journal, 37, 6, 1184, 1194, Canadian Science Publishing, 2000, [Peer-reviewed], [Lead author]
Scientific journal

Use of Japanese sampler in Champlain Sea clay
H Tanaka; KK Hamouche; M Tanaka; Y Watabe; S Leroueil; Fournier, I
Geotechnical Site Characterization, Vols 1 and 2, 439, 444, 1998, [Peer-reviewed]
English, International conference proceedings

Long term behavior of piled bridge abutments in soft clay subjected to backfill loading
Yoichi Watabe; Jiro Takemura; Tsutomu Kimura
Journal of Japan Society of Civil Engineers, 568, III-39, 227, 240, Japan Society of Civil Engineers, 21 Jun. 1997, [Peer-reviewed]
Scientific journal

Stabilities of piled bridge abutments in soft clay subjected to backfill loading
Yoichi Watabe; Jiro Takemura; Tsutomu Kimura
Journal of Japan Society of Civil Engineers, 529, III-33, 177, 189, Japan Society of Civil Engineers, 21 Dec. 1995, [Peer-reviewed]
Scientific journal

Centrifuge model tests on interaction between soft clay and piled bridge abutments subjected to backfill loading
Yoichi Watabe; Jiro Take; Tsutomu Kimura
Journal of Japan Society of Civil Engineers, 523, III-32, 111, 123, Japan Society of Civil Engineers, 21 Sep. 1995, [Peer-reviewed]
Scientific journal

Field measurements and analyses of carbonate production by a coral reef ecosystem : towards the low-water line protection of remote islands
棚谷 灯子; 所 立樹; 渡部 要一; 桑江 朝比呂, 港湾空港技術研究所報告 = Report of the Port and Airport Research Institute, 57, 2, 3, 5,7-33, Jun. 2018
港湾空港技術研究所, Japanese

Mechanical properties of coral-gravel soil : an integrated governing parameter for undisturbed samples
渡部 要一; 金子 崇; 佐々 真志, 港湾空港技術研究所報告 = Report of the Port and Airport Research Institute, 55, 3, 3, 19, Sep. 2016
港湾空港技術研究所, Japanese

Mechanical properties of coral-gravel soil : a parametric study using reconstituted samples
渡部 要一; 金子 崇; 佐々 真志, 港湾空港技術研究所報告, 55, 2, 61, 74, Jun. 2016
港湾空港技術研究所, Japanese

粘性土を母材とするセメント固化処理土・製鋼スラグ混合土の侵食特性に関する実験的研究
清野颯; 渡部要一; 佐々真志; 金子崇; 大塚悟, 地盤工学研究発表会発表講演集(CD-ROM), 51st, 2016

MASWによる潮上帯~潮間帯~潮下帯の連続探査
渡部要一; 佐々真志; 金子崇; 橋本裕司, 地盤工学研究発表会発表講演集(CD-ROM), 51st, 2016

Compression behavior for assembly of DEM crushable cylindrical gravels
Y. Nakata; Y. Watabe, Geomechanics from Micro to Macro, Vols I and II, 281, 284, 2015
English

サンゴ礫混り土や琉球石灰岩の特性と設計・施工上の留意点 (特集 特殊土と基礎工)
渡部 要一; 金子 崇, 基礎工 = The foundation engineering & equipment, monthly : 土木・建築基礎工事と機材の専門誌, 42, 12, 29, 32, Dec. 2014
総合土木研究所, Japanese

Long-term properties of SGM lightweight treated soil curing in seawater
渡部 要一; 菊池 喜昭; 新舎 博, 地盤工学シンポジウム論文集 地盤工学会 編, 59, 675, 680, 2014
地盤工学会, Japanese

地盤工学会論文賞(英文部門)を受賞して(2)(学会の動き)
佐々 真志; 渡部 要一; 梁 順普; 桑江 朝比呂, 地盤工学会誌, 62, 8, 48, 48, 2014
地盤工学会, Japanese

Role of Geoenvironment in the Benthic Ecology and Morphodynamics of Intertidal Flats and Beaches : Ecohabitat Chart and Optimal Design of Dynamically Stable Sandbars
佐々 真志; 渡部 要一; 梁 順普, 港湾空港技術研究所報告, 52, 4, 3, 44, Dec. 2013
港湾空港技術研究所, Japanese

干潟における物理探査の事例 (特集 最近の地盤探査とその応用)
渡部 要一; 佐々 真志, 基礎工 = The foundation engineering & equipment, monthly : 土木・建築基礎工事と機材の専門誌, 41, 9, 90, 92, Sep. 2013
総合土木研究所, Japanese

地盤工学会技術開発賞を受賞して
渡部 要一; 佐々 真志, 地盤工学会誌 = / the Japanese Geotechnical Society, 61, 8, 49, 49, 01 Aug. 2013
地盤工学会, Japanese

Ecological Geotechnics
Sassa, S; Watabe, Y; Yang, J; Kuwae, T, ISSMGE Bulletin, 7, 3, 23, 33, 2013

Proposal of QC/QE of Vertical Impervious Wall in Coastal Waste Reclamation facilities
渡部 要一; 井筒 庸雄; 溝上 健, 港湾空港技術研究所資料, 1262, 2, 46, Dec. 2012
港湾空港技術研究所, Japanese

技術の伝承-現場の教訓から学ぶ- : 軟弱地盤
渡部 要一, 地盤工学会誌 = / the Japanese Geotechnical Society, 60, 1, 44, 51, 01 Jan. 2012
地盤工学会, Japanese

中間軟弱層を有する砂質干潟におけるMASWの適用と測定精度向上に関する研究
渡部要一; 佐々真志; 山田文彦; 林宏一, 地盤工学研究発表会発表講演集(CD-ROM), 46th, 2011

干潟砂州の自律安定機構の解明と覆砂高の最適設計
佐々真志; 渡部要一; YANG Soonbo; 白井一洋, 地盤工学研究発表会発表講演集(CD-ROM), 46th, 2011

粘性土(物理化学的性質)(3.地盤材料,総括,<特集>第46回地盤工学研究発表会)
渡部 要一, 地盤工学会誌, 59, 12, 24, 24, 2011
地盤工学会, Japanese

Evaluation of intertidal flat stratigraphy by MASW technology: interpretation of shear wave velocity structure and safety assessment of artificial intertidal flats
渡部 要一; 佐々 真志; 桑江 朝比呂, Report of the Port and Airport Research Institute, 49, 3, 157, 196, Sep. 2010
港湾空港技術研究所, Japanese

地盤工学の今後の新たな展開 4.生態地盤学
佐々真志; 渡部要一, 地盤工学会誌, 58, 1, 2010

水産有用魚類の餌資源生物分布に果たすサクションの役割
佐々真志; YANG Soonbo; 渡部要一; 梶原直人; 高田宣武, 地盤工学研究発表会発表講演集, 45th, 2, 2010

多チャンネル型表面波探査による人工干潟の安全性評価手法の提案
渡部要一; 佐々真志; 林宏一; 山田耕一, 地盤工学研究発表会発表講演集, 45th, 2, 2010

巣穴底生生物の土砂環境選択行動とパッチ形成の実証
佐々真志; 渡部要一; YANG Soonbo, 地盤工学研究発表会発表講演集, 45th, 2, 2010

生態地盤学
佐々 真志; 渡部 要一, 地盤工学会誌 = / the Japanese Geotechnical Society, 58, 1, 48, 49, 01 Jan. 2010
地盤工学会, Japanese

Role of Waterfront Suction in the Distribution of Food Organisms for Coastal Fish
SASSA Shinji; YANG Soonbo; WATABE Yoichi; KAJIHARA Naoto; TAKADA Yoshitake, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 66, 1, 1126, 1130, 2010
Benthos such as Amphipoda living in coastal sandy sediments are important food organisms for fish, but, factors controlling their distributions remain poorly understood. Here, we aim to solve this question by introducing our new approach encompassing ecology, geophysics and hydraulics / geotechnics. We performed sets of integrated observations / surveys and analyses concerning the in situ intertidal geoenvironments and the benthos distributions at three natural coasts. The results demonstrate that the waterfront suction governs the variety of the habitat environments, involving a range of the degree of saturation, stiffness and void state, and the manifestation of the peak and critical area of densities for the three dominant species are uniquely determined by the magnitudes of such suction which are found to be particular to species throughout the coasts. These findings will effectively contribute to the conservation and management of fishery resources at sandy coasts., 公益社団法人 土木学会, English

Evaluation of sedimentation history of sandbars at entrance of lake Tofutsu, Hokkaido, Japan, by MASW technology
Yoichi Watabe; Shinji Sassa, Geotechnical Special Publication, 210, 1013, 1022, 2010
English

Geoenvironmental Cone Probe Designed for Coastal Waste Disposal Facilities
渡部 要一, 地盤工学会誌 = / the Japanese Geotechnical Society, 57, 9, 43, 44, 01 Sep. 2009
地盤工学会, Japanese

New determination method of soil parameters for performance based design
渡部 要一; 田中 政典; 佐々 真志, Report of the Port and Airport Research Institute, 48, 2, 123, 143, Jun. 2009
港湾空港技術研究所, Japanese

Thickness effects on long-term consolidation behavior of Osaka Bay clays
渡部 要一; 田中 政典; 佐々 真志, Report of the Port and Airport Research Institute, 48, 2, 83, 101, Jun. 2009
港湾空港技術研究所, Japanese

10-year follow-up study on long-term properties of air-foam treated lightweight soil placed in coastal areas
渡部 要一; 田中 政典; 佐々 真志, Report of the Port and Airport Research Institute, 48, 2, 145, 159, Jun. 2009
港湾空港技術研究所, Japanese

A study of the geotechnical investigation results at the planning site of the D-runway of the Tokyo International Airport
渡部 要一; 田中 政典; 佐々 真志, Report of the Port and Airport Research Institute, 48, 2, 103, 121, Jun. 2009
港湾空港技術研究所, Japanese

港湾構造物基礎設計に用いる地盤物性値の評価 (特集 最近の基礎設計に用いる地盤物性値)
渡部 要一, 基礎工, 37, 4, 17, 21, Apr. 2009
総合土木研究所, Japanese

生態地盤学の展開 II:アサリとシオフキの潜砂挙動の違いとその支持力的解釈
酒井陽平; 日下部治; 佐々真志; 渡部要一; YANG Soonbo, 地盤工学研究発表会発表講演集, 44th, 2009

生態地盤学の展開 I:アサリの潜砂性能の系統的解明~稚貝から成貝まで~
佐々真志; 渡部要一; YANG Soonbo, 地盤工学研究発表会発表講演集, 44th, 2009

生態地盤学の展開 III:多種多様な干潟底生生物の住活動性能と適合・限界場の相互関係
佐々真志; 渡部要一; YANG Soonbo, 地盤工学研究発表会発表講演集, 44th, 2009

濤沸湖における湖口周辺砂州の表面波探査結果に基づく堆積形成史の復元
渡部要一; 佐々真志; 林宏一; 小林耕一, 地盤工学研究発表会発表講演集, 44th, 2009

羽田空港D滑走路海底の長期圧密挙動に関するパラメータの検討
渡部要一, 土木学会第64回年次学術講演会集, 2009, 27, 28, 2009

関西国際空港海底粘土の長期圧密挙動に関するアイソタックモデルによる評価
渡部要一, 港研報告, 48, 2, 63, 81, 2009

鳥と地盤と底生生物の関係における水際土砂環境の重要性
佐々真志; 渡部要一; 桑江朝比呂, 地盤工学研究発表会発表講演集, 43rd, 2008

カナダ・フレーザー川河口の広大な干潟の堆積環境
渡部要一; 佐々真志; 桑江朝比呂, 地盤工学研究発表会発表講演集, 43rd, 2008

新港湾基準による地盤定数特性値と一般化された設計コードによる地盤定数特性値の比較
渡部要一, 土木学会第63回年次学術講演会, 第3部, 2008, 885, 886, 2008

東京国際空港再拡張事業における羽田海底粘土の長期圧密特性
渡部要一, 第43回地盤工学研究発表会講演集, 2008, 21, 22, 2008

触り心地の本質, 特集「港の五感」を科学する
渡部要一, 港湾, 日本港湾協会, Vol.85, 1月号, 8, 38, 2008
日本港湾協会, Japanese

港湾・空港の維持管理・更新技術
渡部要一, 土と基礎, Vol.56, No.2, 8, 11, 2008

生態地盤工学の展開 Part2:アサリの潜砂限界強度について
佐々真志; 渡部要一, 地盤工学研究発表会発表講演集, 42nd, 2007

生態地盤工学の展開 Part1:干潟微地形の時空間評価に向けて
渡部要一; 佐々真志, 地盤工学研究発表会発表講演集, 42nd, 2007

Influence of sedimentation process on microfabric of clay deposit
Watabe, Y; Ishii, H; Kang, M.-S; Saitoh, K, Proceedings of the 13th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, Kolkata, 97, 100, 2007

Influence of sedimentation process on microfabric of clay deposit
Watabe, Y; Ishii, H; Kang, M.-S; Saitoh, K, Proceedings of the 13th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, Kolkata, 97, 100, 2007

Geotechnical Investigations for Offshore and Nearshore Developments
渡部 要一, 土と基礎 = Soil mechanics and foundation engineering, 54, 3, 47, 47, 01 Mar. 2006
土質工学会, Japanese

生態地盤環境の性能設計に向けて~Part 1:干潟地盤の堆積構造~
渡部要一; 佐々真志, 地盤工学研究発表会発表講演集, 41st, 2006

潮間帯における粘性土地盤の圧密挙動に関する実験的研究
上田正樹; 池野勝哉; 熊谷隆宏; 渡部要一; 佐々真志, 地盤工学研究発表会発表講演集, 41st, 2006

潮間帯における粘性土地盤の圧密挙動に関する一考察
熊谷隆宏; 上田正樹; 池野勝哉; 渡部要一; 佐々真志, 地盤工学研究発表会発表講演集, 41st, 2006

生態地盤環境の性能設計に向けて~Part 2:干潟底生生物の適合土砂環境場~
佐々真志; 渡部要一, 地盤工学研究発表会発表講演集, 41st, 2006

超低サクション下における干潟土砂強度の変化と相対密度依存性
石井嘉一; 佐々真志; 渡部要一; 斎藤邦夫, 地盤工学研究発表会発表講演集, 41st, 2006

講座 土構造物のメンテナンス 5. 空港における点検と維持管理
渡部要一, 土と基礎, Vol.54, No.7, 55, 62, 2006

鋼製壁による遮水構造の性能に関する現地実証実験
渡部要一; 山田耕一; 沖 健, 基礎工, Vol.34, No.7, 57, 59, 2006
総合土木研究所, Japanese

港湾施設の設計・施工における地盤調査計画
渡部要一; 田中政典, 基礎工, Vol.34, No.8, 21, 24, 2006

地盤環境モニタリングコーンの開発
渡部要一; 土田 孝; 織田幸伸; 田中政典, 基礎工, Vol.34, No.9, 66, 68, 2006
総合土木研究所, Japanese

SGM軽量土工法における最近の取組み
渡部要一, 土木技術, Vol.61, No.10, 53, 58, 2006
土木技術社, Japanese

鋼製遮水壁の遮水性能と適用性に関する研究
渡部要一; 吉野久能; 柿本龍二; 山田耕一; 鵜飼亮行; 沖 健; 岡 由剛; 喜田 浩; 永尾直也; 望月 武; 木下雅敬, 港湾空港技術研究所資料, No. 1142, 1, 65, 2006
港湾空港技術研究所, Japanese

砂質干潟の生態土砂環境場に果たすサクションの役割 —巣穴住活動／保水場の性能評価・設計指針—
佐々真志; 渡部要一, 港湾空港技術研究所報告, Vol.45, No.4, 61, 107, 2006
港湾空港技術研究所, Japanese

Physical and theoretical modelling of the dynamics of tidal flat geo-environments
S. Sassa; Y. Watabe, Proceedings of the 6th International Conference on Physical Modelling in Geotechnics - Physical Modelling in Geotechnics - 6th ICPMG '06, 2, 1285, 1290, 2006

Seismic performance of anchored sheet pile quay wall
Watabe, Y; Imamura, S; Hirano, T; Kishi, M; Yamamura, K, Proceedings of the International Conference on Physical Modelling in Geotechnics, 6th ICPMG, Hong Kong, 1119, 1124, 2006

Geotechnical heterogeneity of undisturbed clay samples retrieved from Osaka Bay
Watabe, Y; Tanaka, M, Proceedings of the International Conference on Civil and Environmental Engineering, ICCEE-2006, 57, 66, 2006

Intertidal sedimentary structures and their formation mechanisms in sandy, muddy, and sand-mud layered flats
Watabe, Y; Sassa, S, Oceans’06, MTS/IEEE, Boston, ISBN: 1-44244-0115-1, 6 pages, 2006

Soil parameters used in the new design code of port facilities in Japan
Watabe, Y; Tanaka, M; Kikuchi, Y, Proceedings of the International Symposium on New Generation Design Codes for Geotechnical Engineering Practice, TAIPEI2006, ISBN 981-270-382-9, Session VI: Geotechnical Uncertainties and Variabilities, 10 pages, 2006

Characterization of alluvial deposits in Mekong Delta,
Takemura, J; Watabe, Y; Tanaka, M, Proceedings of the 2nd International Workshop on Characterisation and Engineering Properties of Natural Soils, Vol.3, 1805, 1829, 2006

Physical and theoretical modelling of the dynamics of tidal flat geo-environments with their morphological impacts
Sassa, S; Watabe, Y, Proceedings of the International Conference on Physical Modelling in Geotechnics, Hong Kong, 1285, 1290, 2006

Seismic performance of anchored sheet pile quay wall
Watabe, Y; Imamura, S; Hirano, T; Kishi, M; Yamamura, K, Proceedings of the International Conference on Physical Modelling in Geotechnics, 6th ICPMG, Hong Kong, 1119, 1124, 2006

Geotechnical heterogeneity of undisturbed clay samples retrieved from Osaka Bay
Watabe, Y; Tanaka, M, Proceedings of the International Conference on Civil and Environmental Engineering, ICCEE-2006, 57, 66, 2006

Intertidal sedimentary structures and their formation mechanisms in sandy, muddy, and sand-mud layered flats
Y. Watabe; S. Sassa, OCEANS 2006, VOLS 1-4, 728, +, 2006
English

Soil parameters used in the new design code of port facilities in Japan
Watabe, Y; Tanaka, M; Kikuchi, Y, Proceedings of the International Symposium on New Generation Design Codes for Geotechnical Engineering Practice, TAIPEI2006, ISBN 981-270-382-9, Session VI: Geotechnical Uncertainties and Variabilities, 10 pages, 2006

Characterization of alluvial deposits in Mekong Delta,
Takemura, J; Watabe, Y; Tanaka, M, Proceedings of the 2nd International Workshop on Characterisation and Engineering Properties of Natural Soils, Vol.3, 1805, 1829, 2006

Engineering Properties and Sampling Techniques in the East Asian Area
TANAKA Masanori; TANAKA Hiroyuki; WATABE Yoichi, 土と基礎 = Soil mechanics and foundation engineering, 53, 2, 25, 27, 01 Feb. 2005
Soil sampling and cone penetration tests were carried out in Saga Ariake and Hachirogata (Japan), Pusan (Korea) and in some regions of Southeast Asian countries such as Bangkok (Thailand), Singapore and Hai phong (Vietnam). The sampling at all sites were carried out following the Japanese sampling method to eliminate technical differences in the sampling methods in these regions. Using the clay samples obtained in the sampling, laboratory tests such as soil classification tests, unconfined compression tests and consolidation tests were subsequently performed. In this paper, the soil properties of these clays are compared and the cone penetration test results obtained from the six sites are also presented., 地盤工学会, Japanese

干潟再生に向けた地盤環境評価~その1:砂質干潟の地盤構造~
渡部要一; 佐々真志; 林宏一, 地盤工学研究発表会発表講演集, 40th, 2005

干潟再生に向けた地盤環境評価~その2:砂質干潟の土砂環境動態~
佐々真志; 渡部要一, 地盤工学研究発表会発表講演集, 40th, 2005

砂質干潟における表面波を用いたS波速度の計測手法の開発
林宏一; 渡部要一; 佐々真志, 地盤工学研究発表会発表講演集, 40th, 2005

Engineering Properties and Sampling Techniques in the East Asian Area(Geotechnical Problem on Oversea Construction Projects : Asian Projects)
Tanaka Masanori; Tanaka Hiroyuki; Watabe Yoichi, 土と基礎, 53, 2, A5, A6, 2005
Soil sampling and cone penetration tests were carried out in Saga Ariake and Hachirogata (Japan), Pusan (Korea) and in some regions of Southeast Asian countries such as Bangkok (Thailand), Singapore and Hai phong (Vietnam). The sampling at all sites were carried out following the Japanese sampling method to eliminate technical differences in the sampling methods in these regions. Using the clay samples obtained in the sampling, laboratory tests such as soil classification tests, unconfined compression tests and consolidation tests were subsequently performed. In this paper, the soil properties of these clays are compared and the cone penetration test results obtained from the six sites are also presented., 土質工学会, Japanese

埋立地の地盤沈下予測と対策, 特集：基礎の沈下予測と制御
渡部要一, 基礎工, Vol. 33, No.12, 61, 64, 2005
総合土木研究所, Japanese

港湾地域における廃棄物処分施設の自然災害対策, 特集記事「防災と環境問題・環境保全との調和」
渡部要一, 自然災害科学, Vol.24, No.3, 221, 226, 2005
自然災害科学会, Japanese

Modeling of consolidation characteristics of clays for settlement prediction of Kansai International Airport
KOBAYASHI M., Proc. of Symp. on Geotechnical Aspects of Kansai International Airport, 2005, 65, 76, 2005

The dynamics of tidal flat geo-environments in an estuary
Sassa, S; Watabe, Y, Proceedings of the 5th International Conference on Coastal Dynamics, American Society of Civil Engineers, 12 pages, 2005

Geophysical characterization of intertidal sedimentary environments, sand, mud and sand-mud layered flats
Watabe, Y; Sassa, S, Proceedings of International Symposium on Fluvial and Coastal Disasters, ISBN4-9902861-0-3, Paper No.13, 1, 10, 2005

Influence of sand fraction on compressibility and hydraulic conductivity of clayey soils
Y. Watabe; K. Saltoh, Proceedings of the 16th International Conference on Soil Mechanics and Geotechnical Engineering, Vols 1-5, 615, 618, 2005
English

Modeling of consolidation characteristics of clays for settlement prediction of Kansai International Airport
Kobayashi, M; Furudoi, T; Suzuki, S; Watabe, Y, Proceedings of the Symposium on Geotechnical Aspects of Kansai International Airport, 65, 76, 2005

The dynamics of tidal flat geo-environments in an estuary
Sassa, S; Watabe, Y, Proceedings of the 5th International Conference on Coastal Dynamics, American Society of Civil Engineers, 12 pages, 2005

Geophysical characterization of intertidal sedimentary environments, sand, mud and sand-mud layered flats
Watabe, Y; Sassa, S, Proceedings of International Symposium on Fluvial and Coastal Disasters, ISBN4-9902861-0-3, Paper No.13, 1, 10, 2005

Watabe, Y. and Saitoh, K.
Proceedings of the; h; International Conference on Soil Mechanics; Geotechnical Engineering, Osaka, Influence of sand fraction on compressibility and hydraulic conductivity of clayey soils, 615, 618, 2005

Effects of disturbance on consolidation properties of lightly overconsolidated undisturbed samples
Murakami Tomoko; Takemura Jiro; Nosaka Tomomasa; Watabe Youichi, Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 153, 154, 2004
ベトナムハイフォンにおいて固定ピストン式(FPS)およびシェルビー式(Shelby)シンフォールサンプリングにより採取した軽く過圧密された粘性土(OCR約2)試料に対して行った一連の圧密試験(標準圧密、定ひずみ試験)の結果、試験機関、サンプリング方法等により圧密特性(e-logp,圧密係数等)に違いが現れた。これについて検討するために、圧密試験前に試料に先行的に圧縮ひずみを与え(軸ひずみ2-4%)、その後圧密供試体を作成し、標準圧密試験を行った。あわせて、初期供試体と圧密リングに隙間を与えた条件でも圧密試験を行い、これらが圧密試験結果に与える影響についても調べた。その結果、4%まででは先行ひずみの影響はFPSサンプルである程度現れるのに対し、Shelbyサンプルではほとんど見られないこと、供試体とリングとの隙間(供試体周辺の乱れ)がe-logpに与える影響が確認にできた。, The Japanese Geotechnical Society

Consolidation tests on undisturbed Hai Phong clay samples by fixed piston and Shelby tube samplers
Takemura Jiro; Man Bui Tan; Watabe Yoichi; Tanaka Masanori, Proceedings of the Japan National Conference on Geotechnical Engineering, 39, 155, 156, 2004
ベトナム国ハイフォンにおいて固定ピストン式(FPS)およびシェルビー式(Shelby)シンフォールサンプリングにより軽く過圧密された粘性土(OCR約2)試料を採取し、2種の試料に対して、ベトナム2機関、日本1機関においてに室内試験を実施した。本報告はその共通試験の中の圧密試験結果についてのものである。試験結果から、FPSとShelby試料の差を確認することができたが、それ以上に試験機関の差が大きく現れ、ある機関の結果では圧密降伏応力(Py)が有効土被り圧を下回るといった結果となった。圧密試験時の有効土被り圧までの間隙比変化とpyとの関係を調べるとこの間隙比変化が大きなほどpyが小さくなり、再圧密時の間隙比変化が乱れの指標として有効であることが確認できた。, The Japanese Geotechnical Society

SGM軽量土工法, 特集：軟弱地盤対策
渡部要一, 土木技術, Vol. 59, No. 8, 93, 99, 2004
土木技術社, Japanese

港湾における軽量混合処理土工法 — SGM軽量土工法, 特集：軽量盛土工法
渡部要一, 基礎工, Vol.32, No.12, 19, 22, 2004
総合土木研究所, Japanese

Microscopic evaluation of 1-D compression for air-form treated lightweight geo-material
Watabe, Y; Itou, Y; Kang, M.-S; Tsuchida, T, Proceedings of the A. W. Skempton Memorial Conference, 1183, 1192, 2004

History of geotechnical database for port and airport construction in Japan
Watabe, Y; Tanaka, M, Proceedings of the International Conference on Engineering Practice and Performance of Soft Deposits, IS-Osaka 2004, 409, 414, 2004

Microstructure of clay observed by SEM in consideration of specimen preparation method
Watabe, Y; Hikiyashiki, H; Kang, M.-S; Tanaka, M; Takemura, T, Proceedings of the 15th Southeast Asian Geotechnical Conference, Bangkok, 21, 26, 2004

On the homogeneity of undisturbed clay samples retrieved from Osaka Bay
Watabe, Y; Takemura, T; Shiraishi, Y; Murakami, T, Proceedings of the 57th Canadian Geotechnical Conference/ the 5th Joint IAH-CNC/CGS Conference, Québec, Session7E Page 1-8, 2004

Microscopic evaluation of 1-D compression for air-form treated lightweight geo-material
Watabe, Y; Itou, Y; Kang, M.-S; Tsuchida, T, Proceedings of the A. W. Skempton Memorial Conference, 1183, 1192, 2004

History of geotechnical database for port and airport construction in Japan
Watabe, Y; Tanaka, M, Proceedings of the International Conference on Engineering Practice and Performance of Soft Deposits, IS-Osaka 2004, 409, 414, 2004

In-situ seismic survey in characterising engineering properties of natural ground
S. Shibuya; S. Yamashita; Y. Watabe; D. C. F. Lo Presti, Geotechnical and Geophysical Site Characterization Vols 1 and 2, 167, 185, 2004
English

Evaluation of in-situ K-0 for Ariake, Bangkok and Hai-Phong clays
Y. Watabe; M. Tanaka; J. Takemura, Geotechnical and Geophysical Site Characterization Vols 1 and 2, 1765, 1772, 2004
English

Microstructure of clay observed by SEM in consideration of specimen preparation method
Watabe, Y; Hikiyashiki, H; Kang, M.-S; Tanaka, M; Takemura, T, Proceedings of the 15th Southeast Asian Geotechnical Conference, Bangkok, 21, 26, 2004

On the homogeneity of undisturbed clay samples retrieved from Osaka Bay
Watabe, Y; Takemura, T; Shiraishi, Y; Murakami, T, Proceedings of the 57th Canadian Geotechnical Conference/ the 5th Joint IAH-CNC/CGS Conference, Québec, Session7E Page 1-8, 2004

地盤材料 ; 粘性土(せん断変形, せん断強度, 残留強度 他, 圧密1, 2)
渡部 要一, 土と基礎 = Soil mechanics and foundation engineering, 51, 12, 35, 36, 01 Dec. 2003
土質工学会, Japanese

Waste Reclamation Site in Coastal Area and Deformable Material for Seepage Control
Watabe Yoichi; Tuchida Takashi; Yamada Koichi; Ukai Akiyuki, 土と基礎 = Soil mechanics and foundation engineering, 51, 8, 32, 33, 01 Aug. 2003
Most wastes from large coastal cities are reclaimed into waste disposal sites in coastal areas, in Japan. Since technologies on seepage control structure have been developed for inland disposal sites, new technologies for coastal disposal sites are strongly demanded. This paper describes characteristic aspects of waste reclamation sites in coastal area and a development of new deformable material for seepage control, which is a mixture of the dredged clay and bentonite. In addition, some influences of sand fraction on the hydraulic conductivity were examined. Finally, the performance of seepage control structure was examined by an experimental proof test in Kure port, Hiroshima, Japan., 地盤工学会, Japanese

国際シンポジウム「沿岸域の軟弱地盤工学」-The Nakase Memorial Symposium-開催報告
土田 孝; 渡部 要一, 土と基礎 = Soil mechanics and foundation engineering, 51, 3, 37, 38, 01 Mar. 2003
地盤工学会, Japanese

ベトナム国ハイフォン粘土の工学的性質
田中政典; 渡部要一; 伊藤康成; 竹村次朗, 第58回土木学会年次学術講演会講演概要集, III, 1, 341, 342, 2003

Evaluation of in-situ lateral earth pressure at rest for marine clay by means of triaxial cell
Y Watabe; A Tanaka; H Tanaka; T Tsuchida, SOFT GROUND ENGINEERING IN COASTAL AREAS, pp.97-103, 97, 103, 2003
English

Watabe, Y., Tsuchida, T., Kang, M.-S., Saitoh, K., Yamada, K. and Ueno, K.: Influence of sand fraction on the impermeability of seepage control clayey layer
Proceedings of the 2nd International Symposium on Contaminated Sediments: Characterisation, Evaluation, Mitigation/Restoration, Monitoring and Performance, Québec, pp.163-169, 2003

Utilization of dredged soil treated with small quantity of cement for waste reclamation landfill
Y Watabe, Proceedings of the Twelfth Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, Vol 1 and 2, pp.417-420, 417, 420, 2003
English

渡部要一, 田中政典, 竹村次朗, 澁谷 啓: 国際化と日本の地盤調査技術
地質と調査, 2003年第4号, pp. 8-16, 2003

Watabe, Y., Tanaka, M. and Takemura, J.: Field and laboratory tests to evaluate the mechanical characteristics of Hai-Phong clay
Pre-Proceeding of Hanoi GeoEngineering 2003 (International Workshop on GeoEngineering), pp.63-72, 2003

Watabe, Y., Tsuchida, T., Kang, M.-S., Saitoh, K., Yamada, K. and Ueno, K.: Influence of sand fraction on the impermeability of seepage control clayey layer
Proceedings of the 2nd International Symposium on Contaminated Sediments: Characterisation, Evaluation, Mitigation/Restoration, Monitoring and Performance, Québec, pp.163-169, 2003

Effect of drying process on the evaluation of microstructure of clays using scanning electron microscope (SEM) and mercury intrusion porosimetry (MIP)
MS Kang; Y Watabe; T Tsuchida, PROCEEDINGS OF THE THIRTEENTH (2003) INTERNATIONAL OFFSHORE AND POLAR ENGINEERING CONFERENCE, VOL 2, pp.385-392, 385, 392, 2003
English

Watabe, Y.: Utilization of dredged soil treated with small quantity of cement for waste reclamation landfill
Proceedings of the 12th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, Singapore, pp.417-420, 2003

Normalization of stress-strain relationship for aged and cemented natural clay
Y Watabe; M Tanaka; T Tsuchida; H Tanaka, DEFORMATION CHARACTERISTICS OF GEOMATERIALS, pp.535-544, 535, 544, 2003
English

Watabe, Y., Tanaka, M. and Takemura, J.: Field and laboratory tests to evaluate the mechanical characteristics of Hai-Phong clay
Pre-Proceeding of Hanoi GeoEngineering 2003 (International Workshop on GeoEngineering), pp.63-72, 2003

SEMおよびポロシメーターを利用した土の微視的構造の観察とその評価
姜 敏秀; 渡部 要一; 土田 孝, 港湾空港技術研究所資料, 1032, 1, 25, Dec. 2002
港湾空港技術研究所, Japanese

沿岸域の廃棄物埋立地における地盤環境の評価と改善に関する研究
土田 孝; 渡部 要一; 織田 幸伸, 港湾空港技術研究所資料, 1025, 1, 96, Jun. 2002
港湾空港技術研究所, Japanese

Evaluation of structure and mechanical properties of Pleistocene clay in Osaka Bay
土田 孝; 渡部 要一; 姜 敏秀, Report of the Port and Airport Research Institute, 41, 2, 45, 91, Jun. 2002
港湾空港技術研究所, English

粘土系遮水材料における微視的構造と透水係数の関係
渡部要一, 第47回地盤工学シンポジウム論文集, 2002, 381, 388, 2002

Stability of quay wall backfilled by lightweight geo-material during earth quake
WATABE Y., Proc. International Conference on Physical Modelling in Geotechnics, St-John's, 2002, pp.435-440, 2002

Geo-environmental cone penetrometer with efficient ground water sampling
WATABE Y., Proc. of 4th International Congress on Environmental Geotechnics, 2002, pp. 71-76, 71, 76, 2002

渡部要一, 土田 孝, 山縣延文, 今村眞一郎, 加藤繁幸: 軽量混合処理土を用いた護岸構造物の地震時安定性
第11回日本地震工学シンポジウム論文集, pp.999-1002, 2002

Kang, M.S., Watabe, Y. and Tsuchida, T.: Effect of drying and preparation method on microscopic analysis on Pleistocene clays using mercury intrusion porosimetry
Proceedings of the International Symposium on Soft Ground Engineering in Coastal Areas, Nakase Memorial Symposium, Yokosuka, pp.73-78, 2002

Yamada, K., Ueno, K., Hada, A., Tsuchida, T., Watabe, Y. and Imai, G.: Development of clayey water interception material in a coastal disposal site
Proceedings of the International Symposium on Soft Ground Engineering in Coastal Areas, Nakase Memorial Symposium, Yokosuka, pp.193-200, 2002

Tsuchida, T., Watabe, Y., Yuasa, H. and Oda, Y.: Construction of seawall for waste landfill in Tachibana Port
Proceedings of the International Symposium on Soft Ground Engineering in Coastal Areas, Nakase Memorial Symposium, Yokosuka, pp.345-352, 2002

Watabe, Y., Tsuchida, T., Imamura, S. and Satoh, T.: Stability of quay wall backfilled by lightweight geo-material during earthquake.
Proceedings of the International Conference on Physical Modelling in Geotechnics, St-John’s, pp.435-440, 2002

Watabe, Y., Tsuchida, T., Tanaka, M., Oda, Y. and Sakai, Y.: Geo-environmental cone penetrometer with efficient ground water sampling.
Proceedings of the 4th International Congress on Environmental Geotechnics, Rio de Janeiro, pp. 71-76, 2002

Watabe, Y., Tanaka, M., Tanaka, H. and Tsuchida, T.: Evaluation of in-situ lateral earth pressure at rest for marine clay by means of triaxial cell
Proceedings of the International Symposium on Soft Ground Engineering in Coastal Areas, Nakase Memorial Symposium, Yokosuka, pp.97-103, 2002

Kang, M.S., Watabe, Y. and Tsuchida, T.: Effect of drying and preparation method on microscopic analysis on Pleistocene clays using mercury intrusion porosimetry
Proceedings of the International Symposium on Soft Ground Engineering in Coastal Areas, Nakase Memorial Symposium, Yokosuka, pp.73-78, 2002

Yamada, K., Ueno, K., Hada, A., Tsuchida, T., Watabe, Y. and Imai, G.: Development of clayey water interception material in a coastal disposal site
Proceedings of the International Symposium on Soft Ground Engineering in Coastal Areas, Nakase Memorial Symposium, Yokosuka, pp.193-200, 2002

Tsuchida, T., Watabe, Y., Yuasa, H. and Oda, Y.: Construction of seawall for waste landfill in Tachibana Port
Proceedings of the International Symposium on Soft Ground Engineering in Coastal Areas, Nakase Memorial Symposium, Yokosuka, pp.345-352, 2002

分割型圧密試験による構造を有する洪積粘性土の圧密挙動
姜 敏秀; 土田 孝; 渡部 要一, 港湾技術研究所報告, 40, 2, 23, 44, Jun. 2001
国土交通省港湾技術研究所, Japanese

浚渫泥土を利用した貧配合セメント処理工の力学特性および材料特性
渡部 要一; 土田 孝; 引屋敷 英人, 港湾技術研究所報告, 40, 2, 3, 22, Jun. 2001
国土交通省港湾技術研究所, Japanese

Residual effective stress in undisturbed samples collected from very large depth
WATABE Y., Proc. of Int. Symp. on Suction, Swelling, Permeability and Structure of Clays, IS-Shizuoka 2001, pp.95-100, 95, 100, 2001

渡部要一, 土田 孝, 佐藤孝夫, 今村眞一郎, 加藤繁幸: 裏込めに軽量混合処理土を用いたケーソン式岸壁の地震時安定性について
第26回地震工学研究発表会, 土木学会, pp.821-824, 2001

土田 孝, 渡部要一, 佐藤孝夫, 今村眞一郎, 山村和弘: 分割法による地震時土圧の算定法とその適用性について
第26回地震工学研究発表会, 土木学会, pp.733-736, 2001

Watabe, Y.: Residual effective stress in undisturbed samples collected from very large depth.
Proceedings of the International Symposium on Suction, Swelling, Permeability and Structure of Clays, IS-Shizuoka 2001, pp.95-100, 2001

Watabe, Y., Furuno, T. and Tsuchida, T.: Mechanical properties of dredged soil treated with low quantity of cement (in Japanese).
WATABE Y., Journal of Geotechnical Engineering, JSCE, No.694, III-57, pp.331-342, 57, 331, 342, 2001
JSCE

地盤環境モニタリングコーンの開発
織田 幸伸; 渡部 要一; 土田 孝, 港湾技研資料, 975, 1, 15, Dec. 2000
国土交通省港湾技術研究所, Japanese

Watabe, Y., Oda, Y. and Tsuchida, T.: Development of a geo-environmental cone penetrometer with efficient ground water sampling.
Proceedings of the Workshop on Underwater Geoenvironmental Problems, KIG Forum2000, Kyoto, pp.185-192, 2000

Watabe, Y., Oda, Y. and Tsuchida, T.: Development of a geo-environmental cone penetrometer with efficient ground water sampling.
Proceedings of the Workshop on Underwater Geoenvironmental Problems, KIG Forum 2000, Kyoto, pp.185-192, 2000

Undrained shear strength of Pleistocene clay in Osaka Bay and its effect on the stability of a large scale seawall structure
Y Watabe; T Tsuchida; K Adachi, COASTAL GEOTECHNICAL ENGINEERING IN PRACTICE, VOL 1, pp.205-210, 205, 210, 2000
English

Mechanical characteristics of a cement treated dredged soil utilized for waste reclamation landfill
Y Watabe; T Tsuchida; T Furuno; H Yuasa, COASTAL GEOTECHNICAL ENGINEERING IN PRACTICE, VOL 1, pp.739-745, 739, 745, 2000
English

Mechanical properties of K-0-consolidation and shearing behaviour observed in triaxial tests for five worldwide clays - Drammen, Louiseville, Singapore, Kansai and Ariake clay
Y Watabe, CHARACTERIZATION OF SOFT MARINE CLAYS, pp.241-251, 241, 251, 1999
English

Comparative study on characteristics of triaxial shear of five worldwide marine clays
Y Watabe, SOIL MECHANICS AND GEOTECHNICAL ENGINEERING, VOL 1, pp.145-148, 145, 148, 1999
English

Watabe, Y.: Mechanical properties of K0-consolidation and shearing behaviour observed in triaxial tests for five worldwide clays –Drammen, Louiseville, Singapore, Kansai and Ariake clay–.
Characterization of Soft Marine Clays, A.A.Balkema, pp.241-251, 1999

Watabe, Y.: Comparative study on characteristics of triaxial shear of five worldwide marine clays.
Proceedings of the 11th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, Seoul, pp.145-148, 1999

一面せん断試験による洪積粘土地盤の強度変形特性の評価
土田 孝; 福原 哲夫; 渡部 要一, 港湾技研資料, 918, 1, 18, Sep. 1998
国土交通省港湾技術研究所, Japanese

Undrained shear strength of Osaka Pleistocene clay and stability of large scale seawall structure
WATABE Y., Report of the Port and Harbour Research Institute, 37, 2, 59, 74, Jun. 1998
国土交通省港湾技術研究所, Japanese

Tanaka, H., Hamouche, K.K., Tanaka, M., Watabe, Y., Leroueil, S. and Fournier, I.: Use of Japanese sampler in Champlain sea clay.
Proceedings of the 1st International Conference on Site Characterization, Atlanta, pp.439-444, 1998

土田 孝, 渡部要一: 関西国際空港の地盤調査
基礎工, Vol.26, No.3, pp.90-94, 1998

Tanaka, H., Hamouche, K.K., Tanaka, M., Watabe, Y., Leroueil, S. and Fournier, I.: Use of Japanese sampler in Champlain sea clay.
Proceedings of the 1st International Conference on Site Characterization, Atlanta, pp.439-444, 1998

Watabe, Y., Takemura, J. and Kimura, T.: Failure Mechanisms of clay deposits improved by SCP and Pile Foundations.
Proceedings of the 2nd International Conference on Soft Soil Engineering, Nanjing, pp.449-454, 1996

Watabe,Y., Takemura,J. and Kimura,T.: Failure Mechanisms of Clay Deposits Improved by SCP and Pile Foundations.
Proc. of 2nd International Conference on Soft Soil Engineering, Nanjing, pp.449-454, 1996

裏込め荷重を受ける軟弱粘土地盤中の杭基礎の安定性に関する基礎的研究
渡部要一, 東京工業大学博士論文, 1995

STABILITY OF PILED BRIDGE ABUTMENTS ON SOFT CLAY DEPOSITS
T KIMURA; J TAKEMURA; Y WATABE; N SUEMASA; A HIROOKA, THIRTEENTH INTERNATIONAL CONFERENCE ON SOIL MECHANICS AND FOUNDATION ENGINEERING, PROCEEDINGS, VOL 2, pp.721-724, 721, 724, 1994
English

Kimura,T., Takemura,J., Watabe,Y., Suemasa,N. and Hirooka,A.: Stability of piled bridge abutments on soft clay deposits.
Proc. of 13th ICSMFE, New Delhi, pp.721-724, 1994

Takemura, T., Watabe, Y., Suemasa, N., Hirooka, A. and Kimura, T.: Stability of soft clay improved with sand compaction piles.
Proceedings of the 9th Asian Regional Conference on Soil Mechanics and Foundation Engineering, Bangkok, pp.543-546, 1991

Takemura,T., Watabe,Y., Suemasa,N., Hirooka,A. and Kimura,T.: Stability of soft clay improved with sand compaction piles.
Proc. of 9th ARC ICSMFE, Bangkok, pp.543-546, 1991

セメント系固化処理土への期待～浚渫土の有効活用～
渡部要一, セメント新聞, 2006年11月27日, 5p

サウンディング調査における技術の伝承～サンプリング調査と比較して～
渡部要一, 地質と調査, 2007第3号, 33, 36

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設置回収型ドレーン工法の開発に関する研究
2002 - 2004

軟弱地盤における安定・変形解析手法の高度化に関する研究
2002 - 2004

鋼製護岸の遮水性能に関する研究
2002 - 2003

海面における管理型廃棄物最終処分場の遮水工法の開発に関する研究
2001 - 2003

年代効果を有する洪積粘土の力学特性に関する研究
1997

Liquefaction potential of pumice sand fill subjected to suffusion: are fine particles are good or bad?
Grants-in-Aid for Scientific Research
01 Apr. 2021 - 31 Mar. 2024
渡部 要一; 佐々 真志; 椋木 俊文
非塑性細粒分がせん断特性や締固め特性に与える影響について調べるために，細粒分45%の火山灰質砂（札幌市清田区里塚地区から採取した盛土材料）を基本として，細粒分を取り除いて15%にした試料，細粒分を加えて70%にした試料について，締固め条件を最適含水比とその前後の含水比，締固め度100%～90%で三軸試験用の供試体を作製し，骨格構造の変化と，それに起因したせん断特性の変化について調べた．
得られた結果は以下の通りである．①最適含水比で最大乾燥密度付近にまで密に締め固められた場合，細粒分の増加はせん断強さを減少させる．②細粒分45%の試料および細粒分70%の試料を締固め度約90%にまで締め固めた供試体は，締固め時の含水比が最適含水比よりも湿潤側の条件で著しいダイレーション傾向を示したが， 最適含水比及び最適含水比よりも5%程度乾燥側の条件では比較的穏やかなダイレーション傾向を示した．③細粒分15%の試料はせん断抵抗角が41°～54°と大きいが，細粒分が45%や70%の試料のせん断抵抗角はいずれも約41°で同程度となり，粗粒分粒子は，細粒分粒子よりもアンギュラリティが高いことが示唆された．
上述の試験は，事前に細粒分含有率が設定された状態の供試体を対象としたものであるが，これらに加えて細粒分45%の試料については，内部侵食試験を実施し，供試体作製後に細粒分の一部が抜け出したときの透水係数の変化やせん断特性の変化についても調べた．
得られ結果は以下の通りである．①締固め度とせん断強さに強い正の相関性があること，②せん断強さは締固め飽和度に影響を受けるがその度合いは一般的な砂質土と比べて不明瞭であること，③締固め飽和度や締固め度が低いほど締め固めた試料の侵食性は高いこと，④侵食を受けた試料は緩詰め条件の場合はせん断強さの増加，密詰め条件の場合は減少を示すことがわかった．
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 21H01421

The mechanisms of submarine slope failures due to earthquakes and the resulting turbidity currents
Grants-in-Aid for Scientific Research
01 Apr. 2019 - 31 Mar. 2022
IZUMI Norihiro
We investigated the physical processes of submarine landslides triggered by earthquakes and the resulting tsunami and turbidity currents from the viewpoints of laboratory experiments, theoretical analysis, and numerical simulations.
We studied the movement of turbidity currents by solving the layer-averaged momentum equations, continuity equation, and the transport equation of suspended sediment of turbidity currents numerically. The results show that the transition from a landslide to a turbidity current that can travel long distances does not depend on the initial suspended sediment concentration or velocity unless the initial Richardson number is greater than unity.
We developed numerical simulation models to reproduce tsunamis caused by a submarine landslide and those generated by the superposition of tsunamis generated by a submarine landslide and an active fault.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 19H02242

Development of integrated prediction and assessment methods of coastal benthic ecology and geoenvironmental dynamics
Grants-in-Aid for Scientific Research
01 Apr. 2015 - 31 Mar. 2020
Sassa Shinji
The present study developed an integrated platform to predict and evaluate coastal benthic ecology and geoenvironmental dynamics. Through its application to fields, the linkage between coastal geoenvironmental dynamics and diverse biological activities of species that belong to Arthropoda, Mollusca, and Annelida, from juvenile to adults, on sandy beaches and sandflats were elucidated under influences of events such as earthquakes, tsunamis and high waves. The developed integrated platform has been shown to predict consistently the species diversity-geoenvironmental dynamics relationship as well as distribution changes of diverse species on sandy beaches and sandflats. The study also developed a sediment stratigraphy evaluation method for entire tidal zones such as supratidal, intertidal and subtidal zones and realized a unified evaluation of the mechanical characteristics of coral mixed soils, and elucidated lasting impacts of a tsunami on sediment-organism interactions in the ocean.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), 15H02265

微視構造を核とした締固め土のパフォーマンス記述：盛土材料の耐侵食性向上を目指して
科学研究費補助金 基盤研究（Ｂ）
Apr. 2017 - Mar. 2020
渡部 要一
Principal investigator, Competitive research funding

Comprehensive study on the 2018 Hokkaido Eastern Iburi Earthquake and its disaster
Grants-in-Aid for Scientific Research
04 Oct. 2018 - 31 Mar. 2019
Takahashi Hiroaki
Comprehensive investigation on the 2018 Hokkaido Eastern Iburi earthquake and its disaster was conducted. Mainshock rupture initiated at deepest part and major slip was occurred in 20-30km deep. Multiple simultaneous landslides in Atsuma town was induced by combination of strong ground shaking and weak sliding layer between pyroclastic fall deposit layers. Halloysite cray minerals was discovered in all sliding layers. Simulation suggested landslides might attack residential houses within 6 seconds. Observed peak ground motions in nearby area were larger than common distance attenuation model. Severe wooden house damage in Mukawa town was due to amplified seismic waves due to site effects. Sounding and boring investigation revealed filled low-density volcanic ash and higher groundwater level in liquefaction area. Electricity blackout caused severe damage in social and economic activities of Hokkaido. These scientific outcomes were explained to residents at public briefing session.
Japan Society for the Promotion of Science, Grant-in-Aid for Special Purposes, Hokkaido University, 18K19952

Proposal of sustainable environmental restoration and management technology using material cycle of World Heritage Ishkeul
Grants-in-Aid for Scientific Research
01 Apr. 2015 - 31 Mar. 2019
Hata Toshiro
Ichkeul Lake which located in northern Tunisia is a UNESCO World Heritage site. In this project, we proposed a lakebed sediment surface solidification with functional liquid or functional granular materials. These solidification methods focused on the enhancement of natural urease production, which can accelerate the calcite precipitation on the lakebed surface. The main outcomes of this project as follows,1) Ishkeul Lake and inlet rivers sediment is inhabiting the specific microbes that can precipitate the calcite with urease enzyme reaction,2) Engineering control of nutrient concentration etc. can enhance the number of microbes and urease activities with target species,3)Field restration work can be carried out with two techniques such as addition of cementation solution with In-situ microbes or functional granular matial addition,4)These proposed method can be expectate with the nitrogen source slow release effect that will be occer with lakebed surface solificiation.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Toyama Prefectural University, 15H02634

Construction of soil genome concept for evaluating the geotechnical properties and its engineering benefits
Grants-in-Aid for Scientific Research
01 Apr. 2015 - 31 Mar. 2018
Tanaka Masanori; OHTSUBO MASAMI; KATAOKA SATSUKI
The following conclusions were obtained.
1) It was confirmed that the amorphous clays such as Kanto Loam change into soils with clay minerals by Transmission Electron Microscope (TEM). From this result, it was proved that volcanic cohesive clays change into clay minerals under marine environment.2)The friction force and viscosity of the clay particles were measured using an Atomic Force Microscope (AFM), and the friction characteristics and physical properties of the surface of clay particle in the micro region were quantitatively examined. The friction force (micro strength) of the clay unit layer was larger than the shear force (macro strength) obtained from large displacement shear test.3)The sediment volume test is a test to identify the degree of expansivity of clays. We showed that this method can be explained by the balance between diffused electric double layer and van der Waals force.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), 15H04041

沿岸土砂堆積環境の連続一体調査手法の開発による堆積形成史復元
科学研究費補助金 基盤研究（Ｂ）
Apr. 2014 - Mar. 2017
渡部 要一
Principal investigator, Competitive research funding

サンゴ礫混じり土の地盤定数評価手法の提案～サンゴ礫骨格とマトリックスの相互作用～
科学研究費補助金 基盤研究（Ｂ）
Apr. 2011 - Mar. 2014
渡部 要一
Principal investigator, Competitive research funding

Barrier geomorphology based on intertidal soil-hydro dynamics
Grants-in-Aid for Scientific Research
01 Apr. 2010 - 31 Mar. 2013
SASSA Shinji; WATABE Yoichi; KURIYAMA Yoshiaki; YAMADA Fumihhiko
A comprehensive set of field observations/surveys, laboratory tests and analyses for the artificially created sandbars in Tokyo Bay, Japan, were performed in order to clarify our recently found mechanism of the morphodynamic stability of intertidal sandbars. The results clearly demonstrated that in the morphodynamic processes where the sediments moved from the unsaturated zone to the saturated zone, namely, where the suction-dynamics induced sediment compaction and associated increase in the surface shear strength became pronounced, the self-stabilization of the intertidal sandbars manifested owing to the impact of the suction dynamics effects on erosion. On the basis of these results, we proposed an optimal design of such dynamically stable sandbars. Our findings can be used widely for the creation and maintanance of such morphological features, which are often crucial for disaster reduction, as well as for conservation and restoration of habitats with diverse biological activity.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Independent Administrative Institution Port and Airport Research Institute, 22656107

Role of geoenvironmental conditions in diverse benthos activity and the ecohabitat chart based on ecological geotechnics
Grants-in-Aid for Scientific Research
2008 - 2011
SASSA Shinji; WATABE Yoichi; KUWAE Tomohiro; HAMANO Tatsuo; SEGUCHI Masahiro; YANG Soonbo
By utilizing our new approach in Ecological Geotechnics, we performed a comprehensive set of field observations and surveys as well as six series of controlled laboratory experiments of benthos-soil systems in order to investigate the responses of six species of invertebrates that belonged to Arthropoda, Mollusca, and Annelida to the varying geoenvironments as manifested in the field. The results of the experiments revealed that for each of the burrowing activities, there exist optimal, transitional and critical geoenvironmental conditions, which are found to differ considerably between species, body sizes and weights. On the basis of these results, we have constructed an ecohabitat chart which enables an interspecific comparison of the burrowing performances and capabilities of the diverse benthic fauna in light of the associated geoenvironments in the field. The observed distributions of diverse benthos at various natural and artificial intertidal flats are found to be well consistent with the ecohabitat chart developed in this study.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Independent Administrative Institution Port and Airport Research Institute, 20360216

Study of application of vacuum consolidation pressure to high moisture content soil/intermediate soil
Grants-in-Aid for Scientific Research
2008 - 2010
KANEDA Kazuhiro; WATABE Youichi; YAMAZAKI Hiroyuki
This paper is discussed about the application of the vacuum consolidation to the high moisture content soil/intermediate soil. The followings are obtained. 1) Using the SYS Cam clay model ,which is the elasto plastic constitutive equation, the shear behaviors of the high moisture content soil/intermediate soil are appropriately expressible and the mechanical behavior is clarified. 2) The vacuum pressure load tests were performed for the intermediate soil, and it was clarified that that soil improvement by vacuum pressure was effective for the intermediate soil. 3) The numerical simulations were performed, and the mechanism of soil improvement for vacuum pressure is clarified. In addition, the possibility of soil improvement with embankment together was examined.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Takenaka Corporation, Takenaka Research and Development Institute, 20560469

保全／修復を目的とした干潟地盤環境の評価と設計技術に関する研究
科学研究費補助金 基盤研究（Ｂ）
Apr. 2006 - Mar. 2009
渡部 要一
Principal investigator, Competitive research funding

Study on characterization of soft soil deposit in delta
Grants-in-Aid for Scientific Research
2004 - 2006
JIRO Takemura; OHTA Heideki; KUSAKABE Osamu; IZAWA Jun; WATABE Yoichi; TANAKA Masanori
In this study collaboration researches about the soil characterization on the alluvial deposits at the Tan An and Can Tho sites in Mekong River Delta, South Vietnam. The following conclusions were drawn from the study.
(1) The Tan An clay, which has been deposited at the riverside of meandering Bam Co Tay River, is highly plastic and very soft with relatively uniform physical properties to a depth of about 8m.
(2) The Can Tho soft clay has been deposited at the flooding area beside the levee of Hau River, one of the major streams of Mekong River. It has significant heterogeneity in the depositional direction, having relatively low plasticity with thin sand seams, which might be created due to large floods.
(3) Depositional speed of the Can To clay is much faster than that of the Tan An clay. C14 dating of the Tan An clay at depth of 6.5m and the Can Tho clay at depth of 19.5m are almost the same, 6,300BP.
(4) Although mechanical and physical properties of the two clays are quite different, both clays have developed high degree of microstructures, which has been confirmed from CRS tests. The ratios of maximum compression index just after the consolidation yield stress to that at the very large consolidation pressure are more than 6 for both clays if excellent quality of sample can be retrieved.
(5) For the non uniform and very thick soft deposit like the Can Tho clay, continuous soil sounding using piezocone is essential for characterizing the site.
(6) Sampling method has significant effect on the sample quality especially for low plastic clay, like Can Tho. JFP is much more superior to Shelby. However, for high plastic clay, the sample collected by Shelby tube sampler might give similar quality to those collected by FFP.
(7) Beside the above mentioned sampling method, there are some problems in the process of soil investigation in Vietnam, such as poor handling of the samples from the site to laboratory and specimen preparation in the laboratory.
(8) Wide varieties of soft soils with different physical and chemical properties prevail in the huge area of Mekong River Delta. Continuous soil investigation studies and practices with good quality sampling, such as thin-walled tube sampler with fixed piston, and laboratory testing as well as appropriate field testing are highly recommended, which can greatly contribute to the proper development in Mekong River Delta.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Tokyo Institute of Technology, 16404011

Study on the relationship between environments of soil sedimentation and engineering properties of the ground in Quaternary Era
Grants-in-Aid for Scientific Research
2003 - 2006
TSUCHIDA Takashi; HIBINO Tadashi; WATABE Yoichi; OTSUBO Masami
The purpose of this study is to find a relationship between the environments of soil sedimentation and the engineering properties of the ground. The findings of the study are summarized as follow:
(1) The process of floc formation and its settling and sedimentation has an important role for the large void ratio structure of natural clay.
(2) By adding small amount of cement to clay slurry, the structure of large void ratio structure of aged clays could be reproduced in the laboratory.
(3) Sedimentation and consolidation tests of marine clay were carried out under flowing water condition. When the water flow was large, the height of the clay decreased with stair-like pattern due to repeat of the erosion and the consolidation. The shear strength of the clay consolidated under flowing water was larger than that consolidated under the stationary water condition.
(4) When soft bottom mud with high water content over the liquid limit is fluidized by the pressure induced by waves, cracks are generated in the surface of the mud. The cracks develop under the action of tensile stress and shear stress caused by the rotation of principal stress in the periodic motion of waves. The mechanism of the acceleration of consolidation of the mud by wave action is elucidated through experimental and numerical studies.
(5) When sandy soil containing 10% fines was subjected to the cyclic water pressure change, it was observed that the fines moved to the upper direction in the soil and finally reached to the surface. The upward movement of fines took place when the water pressure decreased and large excess pore pressure was observed at the ground surface. It was suggested that the occurrence of liquefaction under the cyclic water pressure change was closely related to the upward movement of fines.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hiroshima University, 15206057

Undrained Shear Test of Natural Soft Clay. Stability of Soft Clay Deposits. Engineering Characteristics of Cement Treated Dredged Soil and its Utilization. Influence of Compaction Conditions on Pore-size Distribution and Hydraulic Conductivity. Wast・・・
Undrained Shear Test of Natural Soft Clay.
Stability of Soft Clay Deposits.
Engineering Characteristics of Cement Treated Dredged Soil
and its Utilization.
Influence of Compaction Conditions on Pore-size Distribution
and Hydraulic Conductivity.
Waste Reclamation Landfill and Geo-environmental Investigation
Competitive research funding