研究者詳細 - 西村　伸一

論文 - 西村　伸一

分割表示 163 件中 81 - 100 件目／全件表示 >>

Spatial distributions of strength of an embankment based on synthesis of sounding tests and surface wave method 査読

S. Nishimura, Y. Takayama, K. Fujisawa, M. Suzuki, A. Murakami

APPLICATIONS OF STATISTICS AND PROBABILITY IN CIVIL ENGINEERING 1716 - 1724 2011年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：CRC PRESS-TAYLOR & FRANCIS GROUP

In this research, the spatial distribution of the strength parameters of decrepit earth-fill dams and an identification method are discussed. Swedish Weight Sounding (SWS) tests are conducted to determine the statistical model to represent the spatial distribution of the N-values. The spatial distribution model can be determined with high resolution from the sounding test results, since point estimations for the N-values are available. The Surface Wave Method (SWM), a geophysical exploration method, is also employed here. It can present the averaged image of the N-value distribution. In this research, these two sets of results are synthesized with the indicator simulation method.

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微分方程式で解く土中の侵食

藤澤和謙, 村上章, 西村伸一

地盤工学会誌 59 ( 3 ) 24 - 27 2011年

地盤解析におけるデータ同化

珠玖隆行, 村上章, 藤沢和謙, 西村伸一

地盤工学会誌 59 ( 3 ) 8 - 11 2011年

堤体盛土におけるN値空間分布の推定査読

西村伸一, 高山裕太, 鈴木誠, 村上章, 藤澤和謙

土木学会論文集C（地圏工学） 67 ( 2 ) 252 - 263 2011年

土構造物の信頼性設計における粒子フィルタの適用査読

珠玖隆行, 西村伸一, 村上章, 藤沢和謙

水土の知 79 ( 5 ) 345 - 348 2011年

越流による堤体侵食に関する安定化数値解析査読

藤沢和謙, 村上章, 西村伸一

水土の知 79 ( 8 ) 611 - 614 2011年

砂・粘土混合材料の侵食速度測定と室内越流破堤実験査読

藤沢和謙, 村上章, 西村伸一

農業農村工学会論文集 273 195 - 205 2011年

データ同化に基づいた信頼性解析手法による土構造物の性能照査査読

珠玖隆行, 西村伸一, 村上章, 西村友希, 藤沢和謙

地盤工学ジャーナル 6 ( 3 ) 415 - 426 2011年

条件付シミュレーションによる液状化対策工の信頼性設計査読

西村伸一, 清水英良

農業農村工学会論文集 275 ( 5 ) 329 - 337 2011年

記述言語：日本語出版者・発行元：The Japanese Society of Irrigation, Drainage and Rural Engineering

本研究は，砂質地盤の液状化を対象に，その液状化確率の算定と，リスクの低減を目的とした対策に対して，信頼性設計を実施している．液状化確率は，土質定数の空間的なばらつきを考慮して算定している．第一に，最尤法を利用して，N 値，細粒分含有率F_cの統計モデルを決定し，経験式をとおして動的せん断強度比の算定を行う．これらの確率変数に対して，条件付きシミュレーション法を適用し，地盤の二次元液状化確率の算定を行う．さらに，液状化確率に基づき，最適地盤改良法を決定するための期待総費用最小化に基づく信頼性設計を実施している．地盤改良工法として，サンドコンパクションパイル工法を採り上げ，最適砂置換率を決定している．

DOI： 10.11408/jsidre.79.329

CiNii Article

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その他リンク： https://jlc.jst.go.jp/DN/JALC/10010471080?from=CiNii

Numerical simulation of dynamic behavior of seepage flow with finite volume method

K. Fujisawa, S. Nishimura, A. Murakami

New Frontiers in Computational Geotechnics, Brisbane 75 - 80 2011年

有限体積法による浸透流の動的挙動に関する数値解析査読

藤澤和謙, 西村伸一, 村上章

土木学会応用力学論文集 13 195 - 202 2010年

粒子フィルタによる神戸空港島沈下挙動のデータ同化査読

珠玖隆行, 村上章, 西村伸一, 藤沢和謙, 中村和幸

応用力学論文集 13 67 - 77 2010年

Simultaneous modeling of internal erosion and deformation of soil structures 査読

Kazunori Fujisawa, Akira Murakami, Shin-Ichi Nishimura

Geotechnical Special Publication ( 204 ) 71 - 78 2010年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Piping, as the result of internal erosion of embankments, is a primary cause of embankment breaks. Moreover, hollows or cavities of soil structures have been occasionally reported due to erosion within soils. The inner states of embankments are needed to be estimated to take appropriate measures for the prevention of the accidents of soil structures. In this study, simultaneous modeling of the internal erosion and the deformation of soils is carried out. As for the internal erosion, the equations governing the erosion and the transport of fine particles within a soil mass are derived with the concept of erosion rates of soils. Additionally, the constitutive model which can describe the deformation of soils caused by the internal erosion is proposed in this paper. © 2010 ASCE.

DOI： 10.1061/41105(378)11

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河川堤防の安全性評価に向けた強度分布の推定方法査読

西村伸一, 藤原身江子, 工藤健雄, 内藤秀信, 与那城稔, 土屋善浩, 高山裕太

地盤と建設 28 ( 1 ) 39 - 45 2010年

Coupled problem of saturated-unsaturated seepage flow and internal erosion of soils

K. Fujisawa, D. Niina, A. Murakami, S. Nishimura

UNSATURATED SOILS: THEORETICAL AND NUMERICAL ADVANCES IN UNSATURATED SOIL MECHANICS 837 - 842 2010年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：CRC PRESS-TAYLOR & FRANCIS GROUP

About 50% of dam failures in the world have been triggered by piping, which is a primary cause of embankment breaks. The phenomenon of piping results from the erosion of soil particles and their transport within the soil mass. In this paper, a numerical method to analyze erosion within soils and transport of eroded soil particles is proposed. For the analysis, the saturated-unsaturated seepage flow of the pore liquid, the detachment of soil particles from the soil fabric and the migration of the eroded particles are needed to be considered. As the results of this numerical simulation, the temporal alteration and the spatial distribution of the porosity, the particle size distribution and the concentration of the detached soil particle in the pore liquid, as well as the pore liquid pressure, can be obtained. The results of this analysis have revealed that the method qualitatively predicts the development of piping inside soil structures, such as embankments, as the solutions of the initial and boundary value problem.

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Reliability-based design of earth-fill dams based on the spatial distribution of strength parameters 査読

Shin-ichi Nishimura, Akira Murakami, Ken Matsuura

Georisk 4 ( 3 ) 140 - 147 2010年

記述言語：英語掲載種別：研究論文（学術雑誌）

In this study, a reliability-based design for the improvement of earth-fill dams is presented and the effect of improvement of the embankment for safety against earthquakes is evaluated.An inclined core is considered as the means of improvement for the earth-fill embankment.First, the spatial distribution of the strength of the earthfill materials is discussed, following which the damage level of earth-fill dams is evaluated, using the elastoviscoplastic finite element method (EVP-FEM).By averaging the resulting damage level with the Monte Carlo method, the expected failure costs are calculated.Finally, the effect of this improvement is evaluated by comparing the expected total costs for the original and the restored states of the embankment. © 2010 Taylor &amp
Francis.

DOI： 10.1080/17499511003676655

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Numerical analysis of the erosion and the transport of fine particles within soils leading to the piping phenomenon 査読

Kazunori Fujisawa, Akira Murakami, Shin-Ichi Nishimura

Soils and Foundations 50 ( 4 ) 471 - 482 2010年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Elsevier BV

About 50z of the world's dam failures are triggered by piping, which is a primary cause of embankment breaks. The phenomenon of piping results from the erosion of soil particles and their transport within a soil mass. In this paper, a numerical method is proposed to analyze the erosion within soils and the transport of eroded soil particles by adopting the concept of the erosion rate of soils. In such an analysis, the saturated-unsaturated seepage flow of the pore liquid, the detachment of the soil particles from the soil fabric, and the migration of the eroded particles are taken into consideration, and the equations related to the conservation of the pore liquid and the eroded soil particles are numerically solved. This numerical simulation allows for the procurement of the temporal alteration and the spatial distribution of the porosity, the particle size distribution, and the concentration of the detached soil particles in the pore liquid, as well as the distribution of pore liquid pressure. The results have revealed that the method can reproduce the experimental data from previous studies on the internal erosion of soils and that it qualitatively predicts, from the numerical experiments, the typical development of piping within soils, such as soil blocks and embankments, as the solutions to the initial and the boundary value problems of the governing equations.

DOI： 10.3208/sandf.50.471

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開水路基礎の支持力問題における信頼性解析査読

村上章, 西村伸一, 森充広, 倉田高士, 藤村達也

農業農村工学会論文集 ( 260 ) 69 - 75 2009年4月

Numerical analysis of erosion and migration of soil particles within soil mass

K. Fujisawa, A. Murakami, S. Nishimura

PREDICTION AND SIMULATION METHODS FOR GEOHAZARD MITIGATION 139 - 144 2009年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：CRC PRESS-TAYLOR & FRANCIS GROUP

Internal Erosion caused within soil structures, such as earth dams and irrigation ponds, lead to the piping failures of the structures. Most of studies on the internal erosion of soils have been experimental and the computational method to analyze the phenomenon is currently limited. The purpose of this study is to propose the numerical method for solving the internal erosion and the transport of eroded soil particles and to verify the applicability of the method. In this paper, three equations concerning the seepage flow, the change of porosity due to internal erosion and the transport of the eroded soil particles are introduced and computationally solved. The equation of the seepage flow is solved with Finite Element Method, and Finite Volume Method is applied to the equation of the transport of the soil particles. It is shown that the numerical approach can reproduce the experimental date of the previous study.

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開水路基礎の支持力照査における部分安全係数の算定

村上章, 西村伸一, 鈴木誠, 森充広, 倉田高士, 藤村達也

農業農村工学会論文集 259 71 - 78 2009年

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