研究者詳細 - 西村　伸一

その他リンク： https://jlc.jst.go.jp/DN/JLC/20020753571?from=CiNii

乾湿繰り返しによる底泥の物理化学特性の変化査読

西村伸一, 吉田舞子, 大久保賢治, 珠玖隆行, 柴田俊文

農業農村工学会論文集 303 ( 3 ) II_45 - II_50 2016年

長期圧密予測解析パラメータ同定法の検証査読

西村伸一, 柴田俊文, 珠玖隆行

72 ( 2 ) I_35 - I_43 2016年

Sensitivity analysis of earth-filled dams based on experimental design 査読

Shuku, T, Nishimura, S, Shibata, T

Transactions of The Japanese Society of Irrigation, Drainage and Rural Engineering 83 ( 4 ) II_77 - II_82 2015年

Sensitivity analysis of slope stability based on orthogonal designs 査読

T. Shuku, S. Nishimura, T. Shibata

Computer Methods and Recent Advances in Geomechanics 1043 - 1048 2015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

This study has investigated sensitivity of input parameters in stability analysis of earthen embankments to its factor of safety (F-s) using an experimental design approach. Computer experiments based on orthogonal designs were carried out to achieve efficient experiments, and a linear regression model was applied to analyze the results of the experiment. The Standardized Regression Coefficients (SRCs) obtained from the regression analysis was employed as indexes of the sensitivity of the input parameters to the F-s. The results of the sensitivity analysis showed that the parameters about the geometry of embankments such as height and slope gradient are more sensitive to F-s, although the parameters about hydraulic characteristics of embankment materials are less sensitive to the F-s. In addition, interaction effects between input parameters were also analyzed, and its sensitivity to F-s was discussed.

ため池破堤による想定被害額の簡易評価手法査読

水間啓慈, 西村伸一, 柴田俊文, 珠玖隆行

農業農村工学会論文集 295 ( 1 ) 39 - 46 2015年

記述言語：日本語出版者・発行元：公益社団法人農業農村工学会

地震や集中豪雨による農業用ため池の決壊は，下流域に大きな洪水を発生させ，農業水利施設の中で最も甚大な被害を生じさせる事象の一つである．このため，土地改良施設のリスクを評価しその機能を保全しようとする際に，ため池が決壊した場合の被害額を事前に想定することは非常に重要となる．一方，国が定める被害額算定手法は複雑であり，様々な資産データの収集・整理に多大な労力や時間を必要とする．そこで本研究では，ため池が決壊した場合の氾濫域における被害額を算定する簡易な手法を提案する．提案する手法は，対策を講ずる地区の選定時等に実際に適用できるよう容易に入手可能な資産データのみを用いることとした．3池の氾濫解析結果に提案する手法を適用し被害額を算定した．その結果，規定の方法と大差無く被害額を算定できたことから，提案する手法は有用との結論が得られた．

DOI： 10.11408/jsidre.83.39

応答曲面法によるため池破堤時の被害額の簡易推定査読

その他リンク： https://jlc.jst.go.jp/DN/JLC/20021009394?from=CiNii

豪雨時の越流破堤に対するため池堤体の信頼性設計

西村伸一, 珠玖隆行, 柴田俊文, 藤澤和謙

地盤工学会誌 63 ( 5 ) 30 - 33 2015年

水間啓慈, 西村伸一, 柴田俊文, 珠玖隆行

農業農村工学会論文集 299 ( 5 ) I_147 - I_153 2015年

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

我が国には江戸期以前に築造されたものも含め農業用ため池が数多く存在し, 地震や豪雨のリスクに常に直面している．このため, 遅滞なく効率的に改修等のハード対策や管理体制の強化等のソフト対策を講ずる必要があり, 破堤時の想定被害額を考慮しながら優先順位を決定し計画的に対応を図ることが求められている．しかしながら, 既定の氾濫解析に基づく被害額算定手法は複雑であり, 優先度を検討する数多くのため池の被害額を一度に算定することは難しいことから, 容易に被害額を推定できる簡略化された手法が必要となる．本研究では, このような課題に対応するため, 応答曲面法を用いて被害額を簡易に推定する手法を提案する．応答曲面法とは, 実験計画法に基づく回帰分析により, 因子と応答との定量的な関係を表現する回帰式を作成する手法であり, 得られた回帰式は応答曲面と呼ばれる．被害額算定に考慮すべき多くの因子について感度解析を行い, 被害額の値に大きく寄与する4つの因子を抽出した．これらの因子を用いて作成した応答曲面の決定係数R²は0.84と高く, 行政機関等が行う被害額の簡易推定への実用の可能性が示唆される結果が得られた．

DOI： 10.11408/jsidre.83.I_147

その他リンク： https://jlc.jst.go.jp/DN/JLC/20015919326?from=CiNii

ため池の地震時リスク評価査読

西村伸一, 柴田俊文, 珠玖隆行, 水間啓慈

水土の知 83 ( 12 ) 11 - 14 2015年

Reliability-based design of earth-fill dams to mitigate damage due to severe earthquakes 査読

S. Nishimura, T. Shuku, T. Shibata

Computer Methods and Recent Advances in Geomechanics 1289 - 1294 2015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

This research deals with a strategy for the maintenance of geotechnical structures such as earth-fill dams. Standard PenetrationTest (SPT) N-values are frequently used to determine the soil parameters. Firstly, a statistical model for the N-values is determined from sounding test results. In this research, however, Swedish Weight Sounding (SWS) tests are employed as they are simpler than SPT. Secondly, an indicator simulation is conducted to interpolate the spatial distribution of the N-values, and the results are utilized to find degraded areas inside the embankments and to maintain the embankments. Based on the statistical model for the N-values, the shear strength parameters are derived through the empirical relationships. Then, a reliability analysis of the embankments is conducted considering the variability of the internal friction angle and the seismic hazard.

An eco-friendly design method for geotechnical structures based on LCC 査読

T. Shuku, S. Nishimura, Y. Shimokado, T. Shibata

LIFE-CYCLE OF STRUCTURAL SYSTEMS: DESIGN, ASSESSMENT, MAINTENANCE AND MANAGEMENT 1398 - 1404 2015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

This study presents an eco-friendly design method for infrastructures based on contingent valuation method (CVM). First, a questionnaire survey based on the CVM was conducted to estimate monetary values of stream habitat which can be damaged by river improvement works such as flood prevention works. Second, a design method which can quantitatively evaluate impacts on stream habitat due to flood prevention works was proposed by combining computation of non-uniform flow with a method of stream habitat estimation called physical habitat simulation model (PHABSIM). Finally, monetary value of environmental loss due to flood prevention works was estimated by using results of CVM, and the effectiveness of the eco-friendly design method was discussed through a numerical example.

Uncertainty Evaluation in Slope Failure using Centrifuge Model Tests 査読

Takayuki Shuku, Shin-ichi Nishimura, Ikumasa Yoshida

GEOTECHNICAL SAFETY AND RISK V 353 - 357 2015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：IOS PRESS

Strong nonlinear behavior such as slope failure involves large uncertainties. Even if we conduct model tests on slope failure under the same test conditions, we cannot reproduce the same results although the linear behavior can be reproduced with relative ease. This kind of uncertainties is well known as "aleatory uncertainty" and they should be distinguished clearly from the epistemic uncertainty in reliability-based design. However, characteristics of aleatory uncertainty have not been studied very well so far. This study quantitatively investigates the aleatory uncertainties involved in failure behavior of slopes thorough centrifuge model tests. The centrifuge model tests were conducted under the same test conditions twenty times to quantitatively investigate the variability of slip lines.

DOI： 10.3233/978-1-61499-580-7-353

Diagnosis of Earth-Fill Dams by Several Sounding Tests 査読

Shin-ichi Nishimura, Toshifumi Shibata, Takayuki Shuku

GEOTECHNICAL SAFETY AND RISK V 334 - 339 2015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：IOS PRESS

The spatial distribution of the strength inside an earth-fill dam is identified by sounding tests. In this research, the Swedish Weight Sounding (SWS) test is employed, and the spatially high-density test is possible to identify the spatial correlation structure by the SWS. The correlation structure of an earth-fill could be identified accurately based on the sounding results, and the high resolution of the spatial distribution could be visualized by using the indicator simulation. Consequently, it has been verified the practical use of the spatial distribution of the probability that the N-value is lower than the threshold value, may be used for the maintenance of an earth-fill dam.

DOI： 10.3233/978-1-61499-580-7-334

Reliability-based design of earth-fill dams regarding heavy rains and earthquakes 査読

S. Nishimura, T. Shuku, T. Shibata, K. Fujisawa

LIFE-CYCLE OF STRUCTURAL SYSTEMS: DESIGN, ASSESSMENT, MAINTENANCE AND MANAGEMENT 1390 - 1397 2015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

This research deals with a strategy for the maintenance of geotechnical structures such as earth fill dams. Standard penetration test (SPT) N-values are frequently used to determine the soil parameters. Firstly, based on the statistical model for the N-values, the shear strength parameters are derived through the empirical relationships. Secondly, a reliability analysis of the embankments is conducted considering the variability of the internal friction angle and the seismic hazard. Thirdly, the probability of overflow of earth fills during heavy rains is evaluated. The rainfall intensity is dealt with as a probabilistic parameter, and the various rainfall patterns are tested by the Monte Carlo method.

Sensitivity analysis in stability evaluation of earthen embankments 査読

Takayuki Shuku, Shin-Ichi Nishimura

15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability 1723 - 1726 2015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：Asian Regional Conference on Soil Mechanics and Geotechnical Engineering

This study has investigated sensitivities of input parameters in stability analysis of embankments to safety factor Fs based on experimental deign. In addition to the geotechnical parameters, parameters about geometry such as height, width, and slope gradient of embankments were also considered in the analysis. This study applied regression analysis based on orthogonal design to the sensitivity analysis. The geotechnical parameters required for the stability analysis were used in the sensitivity analysis, and the sensitivity of these parameters to Fs was investigated. The results of the sensitivity analysis showed that the parameters about geometry of embankments such as height and slope gradient are more sensitive to Fs, although the parameters about hydraulic characteristics of embankment material are less sensitive to the Fs.

DOI： 10.3208/jgssp.JPN-034

Scopus

1995年兵庫県南部地震による淡路島北部の被害・無被害ため池堤体の土質特性査読

藤井弘章, 横溝隆之, 難波明代, 堀俊男, 西村伸一, 島田清, 西山竜朗

農業農村工学会論文集 289 ( 1 ) 1 - 18 2014年

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

兵庫県南部地震による被害ため池40個，無被害ため池45個の堤体土から，多変量解析結果を基に，震央距離，堤体量（堤高×堤長），断層距離がほぼ同じ組合せを選び土質特性を比較した．被害ため池堤体土の測定値（平均）は無被害堤体土に比べ，土粒子密度は2.66g/cm³で同じだが，50％粒径は0.514mmで4.5割，含水比は9.4％で約3割，貫入抵抗は223kPaで3割以上小さい．被害率は，含水比および貫入抵抗が低いほど大きくなり，含水比6％未満の堤体は18％以上の堤体の3倍，貫入抵抗が200kPa以下の堤体は400kPa以上の堤体の2.6倍であった．三角座標法土質分類では，被害・無被害の差別化が不十分であった．新たに提案した砂分・細粒分のみに基づくFS分類法により，砂質系土の被害率は，礫質系土の2倍以上となった．比較的簡単な指標により被害・無被害堤体の土質特性が定量化でき差別化できた．

DOI： 10.11408/jsidre.82.1