Faculty Profiles - NODA, Toshihiro

Papers - NODA, Toshihiro

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*Soil-water-air coupled finite deformation analysis based on a rate-type equation of motion incorporating the SYS Cam-clay model Reviewed

Noda, T. and Yoshikawa, T.

Soils and Foundations Vol. 55 ( 1 ) page： 45-62 2015.2

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

With the aim of expanding the soil skeleton-water coupled finite deformation analysis code mounted with the SYS Cam-clay model and capable of accommodating inertia forces to deal seamlessly with soils from the unsaturated to the saturated states, a new soil skeleton-water-air coupled finite deformation analysis method (u-pw-pa-sw formulation) based on the three-phase mixture theory was proposed. The following are the main observations obtained through computations performed under simple conditions using this new method. (1)Simulation of constant cell pressure undrained (and unexhausted) triaxial tests on dense sand specimens with a degree of saturation of 99.9%, which in reality could be considered to be 'saturated soil,' was carried out. It was shown that when the back pressure was not sufficiently large, the existence of air causes desaturation to take place due to the effect of volumetric expansion and no increase in the deviator stress is observed. It was confirmed that the results of this simulation agreed with experimental results. (2)Unlike the conventional method of analysis in which the degree of saturation is not explicitly made an unknown, the current method of analysis, in which the degree of saturation is explicitly made an unknown (u -pw -pa -sw formulation), was shown to be capable of expressing the increase in the degree of saturation even in the case of insular air saturation when the suction is 0.

DOI： http://dx.doi.org/10.1016/j.sandf.2014.12.004

Resilient breakwater foundation against level II earthquake and tsunami

Hazarika, H., Chaudhary, B., Monji, N., Ishikura, R., Kasama, K., Hara, T., Yamazaki, N, Noda, T. and Yamada, S.

The 6th International Geotechnical Symposium on Disaster Mitigation in Special Geoenvironmental Conditions page： 35-46 2015.1

浅層盤状改良工法による戸建て住宅の液状化被害軽減効果の検証と経済性評価 Reviewed

谷　和夫，松下克也，橋本隆雄，山本彰，竹内秀克，野田利弘，規矩大義，大林淳，清田隆

地盤工学ジャーナル Vol. 9 ( 4 ) page： 533-553 2014.12

Language：Japanese Publishing type：Research paper (scientific journal)

2011年東北地方太平洋沖地震により発生した地盤の液状化により、数多くの戸建て住宅が被害を受けた。本研究では、戸建て住宅を対象とした経済的な液状化対策として、浅層盤状改良工法の適用の可能性について検討した。既往の研究と同地震による戸建て住宅の液状化被害を調査し、液状化に対する戸建て住宅に要求される性能として、その傾斜角を、中地震では10/1,000（めり込み沈下量10cmに相当）以下、大地震では16.7/1,000（めり込み沈下量15cmに相当）以下とすることが適切であることを示した。また、被害調査と遠心模型実験を通じて、浅層盤状改良工法による液状化対策の効果を明らかにした。そして、一連の数値解析により、表層地盤の固化工法による地盤改良層厚を3m以上とすることで、液状化に対する戸建て住宅の要求性能を満足することを示した。さらに、浅層盤状改良工法の種類と改良深度、改良面積をパラメータとした経済性評価を行い、同工法の設計に有益な情報を提供した。

DOI： http://dx.doi.org/10.3208/jgs.9.533

Numerical analysis of improvement effect on peaty ground by vertical drain/ vacuum consolidation based on a new macro-element method Reviewed

Nguyen, H.S., Tashiro, M., Noda, T. and Yamada, S.

The 14th International Conference of the International Association for Computer Methods and Advances in Geomechanics (14IACMAG) page： 1145-1150 2014.9

Seismic response analysis of river embankments constructed on alternatively layered soft ground Reviewed

Noda, T., Nakai, K. and Kato, K.

The 14th International Conference of the International Association for Computer Methods and Advances in Geomechanics (14IACMAG) page： 761-766 2014.9

Evaluation of seismic behavior of model earth dams in the geotechnical centrifuge Reviewed

Kawai, T., Ishimaru, M. and Noda, T.

The 14th International Conference of the International Association for Computer Methods and Advances in Geomechanics (14IACMAG) page： 767-772 2014.9

Soil-water coupled finite deformation analysis on subgrade reaction force acting on the underground pile Reviewed

Nakai, K., Noda, T., Komura, S. and Shiratori, Y.

The 14th International Conference of the International Association for Computer Methods and Advances in Geomechanics (14IACMAG) page： 997-1000 2014.9

Verification of a new soil-water-air coupled analysis based on a rate-type equation of motion through realization of uniform deformation of an unsaturated soil specimen Reviewed

Noda, T. and Yoshikawa, T.

UNSAT2014: Unsaturated Soils: Research & Applications page： 613-619 2014.7

Numerical simulation of mechanical behavior of a triaxial silty soil under undrained and various controlled air boundary conditions Reviewed

Yoshikawa, T. and Noda, T.

UNSAT2014: Unsaturated Soils: Research & Applications page： 589-595 2014.7

Simulation of well resistance of vertical drains using new macro element method

Nguyen, H.S., Yamada, S., Noda, T. and Tashiro, M.

COMPSAFE: Computational Engineering and Science for Safety and Environmental Problems page： 164-167 2014.4

Seismic response analysis of river embankments constructed on the alternatively layered soft ground

Nakai, K., Noda, T. and Kato, K.

COMPSAFE: Computational Engineering and Science for Safety and Environmental Problems page： 140-143 2014.4

Seismic and postseismic behavior of river levee on soft clay ground Invited

Kodaka, T., Noda, T., Yoshikawa, T. and Takaine, T.

COMPSAFE: Computational Engineering and Science for Safety and Environmental Problems page： 138-139 2014.4

A 3D soil-water coupled FE analysis of hollow cylinder test concerning non-uniform deformation Reviewed

Xu, B., Nakai, K., Noda, T. and Takaine, T.

Soils and Foundations Vol. 53 ( 6 ) page： 923-936 2013.12

Realization of uniform deformation of soil specimen under undrained plane strain condition based on soil-water coupled finite deformation analysis considering inertia forces Reviewed

Noda, T., Xu, B. and Asaoka, A.

Soils and Foundations Vol. 53 ( 6 ) page： 937-950 2013.12

Acceleration generation due to strain localization of saturated clay specimen based on dynamic soil-water coupled finite deformation analysis Reviewed

Noda, T., Xu, B. and Asaoka, A.

Soils and Foundations Vol. 53 ( 5 ) page： 653-670 2013.10

Simulation of delayed failure in naturally deposited clay ground by soil-water coupled finite deformation analysis taking inertial forces into consideration Reviewed

Yamada, S. and Noda, T.

Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013 page： 841-844 2013.9

Oscillation of acceleration accompanying shear band and subsequent time-dependent behavior in overconsolidated clay under undrained plane-strain conditions Reviewed

Noda, T. and Xu, B.

Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013 page： 403-406 2013.9

Excavation analysis of ground using SPH method Reviewed

Vol. 16 page： I_341-I_350 2013.9

Language：Japanese Publishing type：Research paper (scientific journal)

In order to solve large deformation problem of geomaterials, the SPH method is used which is
a kind of particle method based on the meshless Lagrangian scheme. The method can solve large deformation problems without mesh distortion. Moreover, it can handle the governing equations and existing constitutive models for geomaterials based on a continuum mechanics. To express various states of the soil, the elasto-plastic constitutive model taking account of soil skeleton structure is introduced into the method. In this paper, in order to verify the numerical scheme, a simulation of simple shear test is carried out. The obtained results are compared with theoretical solutions. Furthermore, the excavation problems for loose and dense sand ground are solved. From a series of the numerical results, the effectiveness of the method with the constitutive model of high performance is demonstrated.

Influence of brittle property of cement treated soil on undrained bearing capacity characteristics of the ground Reviewed

Yamada, S., Noda, T., Asaoka, A. and Shiina. T.

Geotechnical Engineering Journal of the SEAGS & AGSSEA Vol. 44 ( 3 ) page： 84-93 2013.9

Language：English Publishing type：Research paper (scientific journal)

In this study, the influence of brittle property of geomaterials on the failure behavior of the ground in an undrained bearing capacity problem was investigated numerically from the standpoint of taking the brittle behavior of cement treated soil as softening behavior of the soil element. The numerical analyses were performed using the soil-water coupled finite deformation analysis code GEOASIA mounted with the SYS Cam-clay model, which describes the soil skeleton structure at work. Cement treated ground and naturally deposited clay ground were modelled and compared, and it was found that they showed widely differing failure processes depending on differing initial conditions. Especially, it was found that when progressive failure in which strain localization region develops due to propagation of material failure occurs, even though the ground is composed of brittle materials such as cement treated soil, those brittle properties do not directly manifest in the load-settlement relationship. Additionally, the investigation revealed that, since every soil element on the slip lines does not reach its peak strength simultaneously when progressive failure occurs, post-peak material properties, i.e. the ratio of residual strength to peak strength and softening rate from peak to residual state, affect the bearing capacity of the ground.

ゆるい砂地盤における砂圧入締固めによる周辺地盤への3次元影響評価解析 Reviewed

竹内秀克，河村精一，野田利弘，浅岡顕

地盤工学ジャーナル Vol. 8 ( 2 ) page： 239-249 2013.6

Language：Japanese Publishing type：Research paper (scientific journal)

「砂圧入式静的締固め工法」は，地盤中に流動化砂を圧入・押し広げることにより，周辺地盤に強制的に圧縮・せん断を与え，締固め効果を期待する工法である。工法の性格上，地盤に変位や応力を与えることに伴い，近接の既設構造物に少なからず影響を及ぼす。この影響の程度を予測／評価するためには，土要素の平均有効応力変化に伴う圧縮挙動だけでなく，せん断応力に伴うダイレイタンシー挙動もより精度よく評価する必要がある。本研究では，自然粘土～中間土～砂を一貫して説明することが可能な弾塑性構成式(SYSカムクレイモデル)を搭載する水～土連成有限変形解析を用い，3次元条件で砂圧入締固めの過程を再現して解析を実施した。この結果，砂圧入式静的締固め施工時の，周辺砂地盤の地表面および地中発生変位の距離に伴う減衰(距離減衰)や，近接構造物に与える地盤反力(側圧)分布は施工位置からの距離に応じて減少することがわかった。

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