Publishing type：Part of collection (book)   Publisher：Springer International Publishing  

Abstract

This chapter presents a summary of the calibration exercises (i.e., element test simulations) submitted by nine numerical simulation teams that participated in the LEAP-ASIA-2019 prediction campaign. The standard sand selected for the campaign is Ottawa F-65, and researchers have developed several efforts to increase the database of laboratory tests to characterize the physical and mechanical properties of this sand (Carey TJ, Stone N, Kutter BL, Grain Size Analysis and Maximum and Minimum Dry Density of Ottawa F-65 Sand for LEAP-UCD-2017. Model tests and numerical simulations of liquefaction and lateral spreading: LEAP-UCD-2017. Springer, 2019; El Ghoraiby MA, Park H, Manzari MT. Physical and mechanical properties of Ottawa F65 sand. In: Model tests and numerical simulations of liquefaction and lateral spreading: LEAP-UCD-2017, Springer, 2019; Ueda K, Vargas RR, Uemura K, LEAP-Asia-2018: Stress-strain response of Ottawa sand in Cyclic Torsional Shear Tests, DesignSafe-CI [publisher], Dataset, https://doi.org/10.17603/DS2D40H, 2018; Vargas RR, Ueda K, Uemura K, Soil Dyn Earthq Eng 133:106111, 2020; Vargas RR, Ueda K, Uemura K, Dynamic torsional shear tests of Ottawa F-65 Sand for LEAP-ASIA-2019. Model tests and numerical simulations of liquefaction and lateral spreading: LEAP-ASIA-2019, Springer, 2023). The objective of this element test simulation exercise is to assess the performance of the constitutive models used by the simulation teams for simulating the experimental results of a series of undrained stress-controlled cyclic torsional shear tests on Ottawa F-65 sand for two different relative densities (Dr = 50% and 60%) (Ueda K, Vargas RR, Uemura K, LEAP-Asia-2018: Stress-strain response of Ottawa sand in Cyclic Torsional Shear Tests, DesignSafe-CI [publisher], Dataset, https://doi.org/10.17603/DS2D40H, 2018; Vargas RR, Ueda K, Uemura K, Soil Dyn Earthq Eng 133:106111, 2020; Vargas RR, Ueda K, Uemura K, Dynamic torsional shear tests of Ottawa F-65 sand for LEAP-ASIA-2019. Model tests and numerical simulations of liquefaction and lateral spreading: LEAP-ASIA-2019, Springer, 2023). The simulated liquefaction strength curves demonstrate that majority of the constitutive models are capable of reasonably capturing the measured liquefaction strength curves both for Dr = 50% and 60%. However, the simulated stress paths and stress-strain relationships show some differences from the corresponding laboratory tests in some cases.

DOI： 10.1007/978-3-031-48821-4_2

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Publishing type：Part of collection (book)   Publisher：Springer International Publishing  

Abstract

This chapter presents a summary of Type-B and Type-C numerical simulations submitted by nine numerical simulation teams that participated in the LEAP-ASIA-2019 prediction campaign, with the results of a selected set of centrifuge model tests on the seismic behavior of a uniform-density, 20-m-long, and 5-degree sandy slope. Time histories of response accelerations, excess pore water pressures, and lateral displacements at the ground surface are compared to the experimental results. A majority of Type-B and Type-C numerical simulations were capable of simulating well the experimental trends observed in the centrifuge tests; in particular, Type-C simulations were found to capture the measured responses more accurately by adjusting the model parameters. Although it is quite challenging to perfectly capture all measured responses (e.g., accelerations, pore pressures, and displacements), the simulation exercises demonstrate that the numerical simulations can be further improved by accumulating high-quality experimental results as a database.

DOI： 10.1007/978-3-031-48821-4_3

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japanese Geotechnical Society  

DOI： 10.3208/jgssp.v10.os-13-02

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japanese Geotechnical Society  

DOI： 10.3208/jgssp.v10.os-40-03

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.soildyn.2023.108110

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

DOI： 10.2208/jscejj.22-13014

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s11600-023-01158-6

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Other Link： https://link.springer.com/article/10.1007/s11600-023-01158-6/fulltext.html

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.sandf.2022.101218

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Language：English   Publishing type：Part of collection (book)   Publisher：Springer International Publishing  

DOI： 10.1007/978-3-031-11898-2_33

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Part of collection (book)   Publisher：Springer International Publishing  

DOI： 10.1007/978-3-031-11898-2_118

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Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

A round-robin centrifuge model test for an identical saturated sloping deposit with various initial conditions was conducted in the framework of liquefaction experiments and analysis project (LEAP) with 10 international institutes. To pursue two main objectives: (1) the validation of the generalized scaling law (GSL); and, (2) the development of additional experimental data that fill the gaps in the previous LEAP, each institute was assigned two tests, identical in prototype scale: a model following the generalized scaling law and a model following conventional centrifuge scaling law. The test results show a significant match in the dynamic behavior of these models, which validates the applicability of the GSL under given conditions. However, in this study, a deviation is observed when the surface ground deformation becomes larger (i.e., 250 mm). The trend surface that correlates peak amplitude of input acceleration (PGAeff), the relative density of the ground (Dr_qc(2.0 m)), and surface lateral displacement (Ux) is updated and confirmed with new data sets.

DOI： 10.1016/j.soildyn.2022.107237

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Publishing type：Research paper (scientific journal)   Publisher：Informa UK Limited  

DOI： 10.1080/13632469.2020.1751346

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Authorship：Lead author   Publishing type：Part of collection (book)  

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Authorship：Lead author  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media Deutschland GmbH  

DOI： 10.1007/s10706-020-01619-5

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Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.soildyn.2020.106472

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Language：Japanese   Publisher：The Japanese Geotechnical Society  

<p>When laying water pipelines, excavated soil is generally disposed and replaced with commercially available sandy material. Reuse of the excavated soil yields reduction of both the environmental loads and the construction costs. Although "The guideline for use of excavated soil" by Ministry of Land, Infrastructure and Transport, specifies reusable soil types, it is not common practice to use the excavated soil for the laying of water pipeline because the specification requires complicated laboratory soil tests for the judgement. In this study, the applicability of the on-site simple method, called the "FK method", is evaluated through a series of laboratory tests and model tests by using soil samples collected from various regions in Japan. As a result, the FK method successfully indicated compaction characteristics and bearing capacity of excavated soil. Hence, the method can be used on-site to judge the availability of excavated soil for water pipe laying works.</p>

DOI： 10.3208/jgs.15.257

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Language：Chinese   Publishing type：Research paper (scientific journal)   Publisher：Academia Sinica  

DOI： 10.16285/j.rsm.2018.1271

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Language：Japanese   Publishing type：Research paper (international conference proceedings)  

A round-robin centrifuge model test for an identical saturated sloping deposit with various initial conditions was conducted in the framework of liquefaction experiments and analysis project (LEAP) with 10 international institutes. To pursue two main objectives: (1) the validation of the generalized scaling law (GSL); and, (2) the development of additional experimental data that fill the gaps in the previous LEAP, each institute was assigned two tests, identical in prototype scale: a model following the generalized scaling law and a model following conventional centrifuge scaling law. The test results show a significant match in the dynamic behavior of these models, which validates the applicability of the GSL under given conditions. However, in this study, a deviation is observed when the surface ground deformation becomes larger (i.e., 250 mm). The trend surface that correlates peak amplitude of input acceleration (PGAeff), the relative density of the ground (Dr_qc(2.0 m)), and surface lateral displacement (Ux) is updated and confirmed with new data sets.

DOI： 10.1016/j.soildyn.2022.107237

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

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Taylor and Francis Ltd.  

DOI： 10.1080/1064119X.2018.1485793

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Publishing type：Research paper (international conference proceedings)  

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Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.soildyn.2017.05.015

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Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.soildyn.2017.10.014

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DOI： 10.1016/j.soildyn.2017.05.018

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DOI： 10.1080/13632469.2018.1469441

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Language：English   Publishing type：Research paper (international conference proceedings)  

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DOI： 10.2208/jscejseee.74.I_598

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Language：Japanese   Publisher：公益社団法人 土木学会  

熊本地震では，水道施設にも多数の被害が生じたが，河川に囲まれた軟弱な粘土層と飽和砂層で構成された低地にある水道用井戸の水源地周辺においては，想定していなかった顕著な地盤変状に伴う水道施設の被害や，新耐震基準以降に建設された水道施設の建築物に基礎被害が多数確認された．筆者らは，浄水場や下水処理場および上下水道管路網の地震被害軽減対策を研究しており，これらの水道施設の被害と液状化を含む地盤の地震時挙動との関連性や対策に関する知見を得るために各種調査や検証解析を実施した．本報告では，これらの調査結果を報告するとともに，熊本市の水道事業において特に重要な井戸水源地施設の基礎杭及び井戸ケーシングを対象として，地震被害のメカニズムや要因を分析し，今後の耐震設計における留意点などを考察した．

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DOI： 10.4186/ej.2018.22.3.291

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ltd  

DOI： 10.1016/j.soildyn.2018.05.005

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DOI： 10.1016/j.soildyn.2018.07.00

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Language：Japanese   Publisher：関西大学先端科学技術推進機構  

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Language：Japanese   Publisher：Institute of Social Safety Science  

<p>During a scenario earthquake with <i>M</i>_W9.0 along the Nankai Trough, strong ground motion is expected in the focal area, Wakayama Prefecture, Japan. In order to simulate the seismic damage of railway structures, it is necessary to estimate strong motions at the sites of interest with sufficient accuracy, taking into account local site effects. In this study, seismic waveforms at 54 sites for permanent railway station along JR Kinokuni Line were predicted based on the SMGA models considering the empirical site amplification and phase effects. The predicted seismic waveforms will be useful for rational safety assessment of a railway structure.</p>

DOI： 10.11314/jisss.31.339

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;Liquefaction was investigated after the 6.8 Mw earthquake on March 24, 2011 (Tarlay earthquake) in Chiang Rai Province, Northern Thailand. Several investigations including soil boring, SPT, and SASW tests were carried out and the results were used to perform one dimensional wave propagation analysis using finite element method. The maximum acceleration of 0.206 g recorded in Chiang Rai was used as the input motion. The input motion was applied at bottom of soil column to observe soil behavior under seismic loading. The result shows that liquefaction could occur at shallow depth (0 to 16.5 m), which is also followed by settlement (1.8 to 4 cm) due to compressibility of soil during earthquake. The analysis result indicates that there is no significant dissipated pore water pressure on liquefied layer. The longer duration of liquefaction is identified on layer (SP-SM), which have the low SPT values. Excess pore water pressure from bottom layer might also concentrate at this layer. The concentration of excess pore water pressure may trigger the duration of liquefaction up to 50 seconds. In addition, the excess pore water pressure ratio linked to impacted depth warns that the soils with excess pore water pressure in range of 0.9 to 1 are possible to get worse impact if a stronger earthquake attacks this area in the future.

DOI： 10.2208/jscejseee.73.I_135

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Publishing type：Research paper (international conference proceedings)  

DOI： 10.1201/9781315161563-10

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Language：English   Publishing type：Research paper (international conference proceedings)  

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

DOI： 10.1016/j.soildyn.2016.09.009

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J-GLOBAL

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

DOI： 10.1016/j.soildyn.2016.08.002

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Language：Chinese   Publishing type：Research paper (scientific journal)   Publisher：Academia Sinica  

DOI： 10.16285/j.rsm.2016.08.039

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：The Japanese Geotechnical Society  

DOI： 10.3208/jgssp.JPN-026

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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

DOI： 10.1016/j.compgeo.2015.05.011

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;Occurrence of liquefaction in the wide range of Kanto plain has been reported after the great Tohoku earthquake. Tremendous damage associated with the liquefaction includes damage on residential houses, roads, and water and sewage systems. As professional engineers and researchers who design and construct water treatment and sewage plants and pipelines, and study geotechnical site conditions, the authors conducted investigation through interviewing with the responsible personnels in Chiba Prefecture, Urayasu city, Itako city, Wanigawa water treatment plant, and Amagasaki city which suffered severe damage at the 1995 Hyogoken-Nanbu earthquake. Based on the hearing investigation, analyses are made on characteristics of those damages due to liquefaction and local site conditions and some measures for mitigation are introduced.

DOI： 10.2208/jscejseee.71.I_983

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Language：Japanese  

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Language：Japanese  

CiNii Books

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Language：English   Publisher：The Japanese Geotechnical Society  

Large-scale liquefaction was caused by the 2011 off the Pacific coast of Tohoku, Japan, earthquake and many pipes in the liquefied ground suffered serious damages. One of the issues pointed out after the earthquake is the dynamic behavior and the mechanism of pipes near a structure in the liquefied ground. This study focuses on evaluating the dynamic behavior through centrifuge model test. Test results show that the uplift of pipes in the liquefied ground occurred during an earthquake and liquefaction happens at that time. After an earthquake, pipes start to sink with increasing effective stress. The characteristic of damage mechanism depends on the depth of pipes and the state of ground (in liquefiable layer, at ground water level, or in the unsaturated layer). The data also shows that the direction of force interacting pipes during liquefaction was only bending direction. So we should reconsider the design criteria for pipes which is widely used in Japan applying to axial force.

DOI： 10.3208/jgssp.v03.j02

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

DOI： 10.1016/j.soildyn.2014.05.006

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Language：Japanese  

CiNii Books

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10422448

Language：English   Publishing type：Research paper (international conference proceedings)  

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Other Link： http://orcid.org/0000-0002-1543-1626

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

DOI： 10.1016/j.compgeo.2013.09.022

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;Coastal embankment has been constructed to protect coastal area for earthquake and tsunami. But seismic-resistant shortage is pointed out. To improve the disaster prevention performance, seismic countermeasures should be optimized both performance and cost, and evaluated ductility for Huge earthquake hard to collapse. In this study intended for permeable grouting method and examine effect and ductility by centrifuge model tests. It is proved that under the sea wall remarkable share deformation occurs due to liquefaction, so improvement this area is quite effective and seismic-resistant can be optimized. It is confirmed that permeable grouting method has peculiar ductility which primary factor is cohesion. Deformation characteristic is improved to the cyclic shear loading, seepage of pore water is restricted and with dilatancy of soil an effective stress increased and shear resistance became higher.

DOI： 10.2208/jscejseee.70.I_44

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;The characteristics of a soil layer are not usually uniform, and uneven settlement was often observed in a clay stratum. In case of reclamation above the clay stratum, there is a possibility that the uneven settlement in the clay stratum affect the characteristics of the sand layer. Especially, the stress state of the ground might be affected. In this research, the stress distribution of the ground above the clay layer with a settlement were investigated by a series of centrifuge model test. As a result, the non-uniform stress distribution in the ground due to the settlement is observed. This non-uniform distribution of the stress correspond to the &plusmn;50% level of the variation in observed in-situ SPT N value.

DOI： 10.2208/jscejseee.70.I_751

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

DOI： 10.1016/j.enggeo.2013.07.011

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

DOI： 10.1002/nag.2087

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Publishing type：Research paper (scientific journal)  

DOI： 10.1002/nag.2084

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Language：Japanese   Publisher：京都大学防災研究所技術室  

京都大学防災研究所の遠心力載荷装置は2年前に更新を行った。更新によりアームの剛性を強化し, 振動台駆動時に加振周波数50 Hz付近でアームが共振する問題を解消した。しかし, 更新後の装置について, 実験者からプラットフォームの剛性不足, 新規に導入したプラットフォーム固定方式の欠陥, 振動台から上下動が発生しているとの指摘があった。これらの問題を改善するために, 昨年再度装置の改修を行った。改修によりプラットフォームを再度更新し, 固定方式についても改造を行った。本調査では, 更新したプラットフォームおよび振動台やアームに加速度計を設置し, 振動台の加振試験を行い, 振動特性を調査した。その結果, プラットフォームの剛性不足が改善したことを確認した。また, 振動台で発生していた上下動は, プラットフォームの固定, DITHERと呼ばれる振動台の制御信号, 振動台の機械的構造が主な原因であることがわかった。

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

DOI： 10.1002/nag.1091

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;In order to verify the applicability of strain space multiple mechanism model based on finite strain (both total Lagrangian (TL) and updated Lagrangian (UL)) formulations, seismic response analyses are performed on Breakwater No.7 in Kobe Port during 1995 Hyogoken-Nanbu earthquake. Both infinitesimal and finite deformation analyses are performed to examine how the effect of geometrical nonlinearity affects the analytical results. As an input dilatancy parameter in the model, two types of undrained shear strength (20 kPa and 40 kPa) are adopted according to the results of undrained triaxial compression tests. The settlements at the top of the caisson in the infinitesimal deformation analyses are 3.62 m and 2.89 m for the undrained shear strength of 20 kPa and 40 kPa, both of which exceed the upper limit of measurements (2.6 m). In contrast, the computed settlements in the TL/UL formulations with the undrained shear strength of 20 kPa and 40 kPa are 2.46/2.46 m and 1.93/1.88 m, respectively, both of which fall inside the measured range (between 1.4 and 2.6 m). The results confirm that the TL and UL formulations are numerically equivalent and the effect of geometrical nonlinearity has to be accurately considered in predicting the seismic response of port structures such as breakwaters.

DOI： 10.2208/jscejseee.69.I_385

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

DOI： 10.1061/(ASCE)GT.1943-5606.0000769

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Language：Japanese  

The geotechnical centrifuge at the Disaster Prevention Research Institute, Kyoto University was renewed two years ago. Consequently, the rigidity of the main frame of the device had improved. However, some problems emerged by subsequent use. The 1st problem was that the rigidity of the platform part of the device was low. The 2nd one was that the fixed system of the platform part adopted did not function. The 3rd one was that vibration of the up-and-down direction in the shaking table occurs when dynamic centrifuge tests were. In order to solve those problems, the platform part was renewed last year to what has high rigidity, and the fixed system was also changed. In the present study, we investigated the dynamic characteristics of the shaking table and the platform part by measuring the vibration when dynamic centrifuge tests were. As a result, it was found that the causes of vibration of the up-and-down direction were the structure of the shaking table and the control signal called "DITHER". Additionally, it compared with the result when not fixing a platform part. Based on the comparison results, it is suggested that it be used without fixing the platform part.

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

DOI： 10.1061/(ASCE)GT.1943-5606.0000615

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Language：Japanese   Publisher：The Japanese Geotechnical Society  

This paper reports geotechnical damages in the northern area of Miyagi prefecture caused by the 2011 off the Pacific coast of Tohoku Earthquake on March 11, 2011. A joint reconnaissance team organized by Tohoku branch and Kansai branch of the Japanese Geotechnical Society carried out extensive field surveys in the area from April 5 to 10 and from April 29 to 30, 2011. This paper consists of the main results from these surveys and subsequent researches on the damage such as failure of river embankments and coastal levees, coastal erosion caused by tsunami, damage of port and harbor facilities, failure of cut and banked slopes of roads and railroads, and occurrence of liquefaction and subsidence. Although some results have already been reported as news flash to the Journal of the Japanese Geotechnical Society, this paper provides inclusive summaries and more detailed investigations on the damage in the northern area of Miyagi prefecture. In separate sections of this paper, outlines of the damage in each object are briefly summarized, and then several typical damage cases are presented and these mechanisms are discussed in detail.

DOI： 10.3208/jgs.7.37

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Language：Japanese  

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Other Link： http://hdl.handle.net/2433/171985

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

DOI： 10.1680/ijpmg.2011.11.4.138

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Language：English   Publisher：Japan Society of Civil Engineers  

The non-linear response of coupled soil-pile-structure systems to seismic loading is parametrically studied in the frequency domain using two-dimensional (2D) finite elements (FE). The soil-pile interaction in three dimensions (3D) is idealized in the 2D type using soil-pile interaction springs with non-linear hysteretic load displacement relationships. The system under investigation comprises of a single degree of freedom structure supported by an end-bearing single pile founded in a homogenous sand layer over rigid rock. Comparisons with established results from the literature suggest that the adopted FE model reasonably captures the essential features of the seismic response of the coupled soil-pile-structure system. Numerical results demonstrate the strong influence on the effective natural period of the foundation properties. The effect of non-linear soil behavior and soil profile as well as the frequency content of excitation on both kinematic and inertial interactions is illustrated. The relative contributions of kinematic and inertial interaction to the development of dynamic pile bending are clarified.

DOI： 10.2208/jscejam.67.I_471

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Language：Japanese  

The geotechnical centrifuge at the Disaster Prevention Research Institute, Kyoto University was renewed two years ago. Consequently, the rigidity of the main frame of the device had improved. However, some problems emerged by subsequent use. The 1st problem was that the rigidity of the platform part of the device was low. The 2nd one was that the fixed system of the platform part adopted did not function. The 3rd one was that vibration of the vertical direction in the shaking table occurs when dynamic centrifuge tests were. In order to solve those problems, the platform part was renewed last year to what has high rigidity, and the fixed system was also changed. In the present study, we investigated the dynamic characteristics of the shaking table and the platform part by measuring the vibration when dynamic centrifuge tests were. As a result, it was found that the causes of vibration of the vertical direction were the structure of the shaking table and the control signal called "DITHER". Additionally, it compared with the result when not fixing the platform part. Based on the comparison results, it is suggested that it be used without fixing the platform part.

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Other Link： http://hdl.handle.net/2433/161853

Language：English  

To verify the generalized scaling law, dynamic centrifuge tests under two different centrifugal accelerations of 25 g and 50 g are conducted. The model ground constitutes of a flat dry sand layer. With the scaling law, a prototype ground is scaled down to 1/100. A sinusoidal input acceleration of frequency 1.0 Hz, maximum amplitude 0.5 g, and duration 14 sec in prototype scale is applied to the model ground. Each model is exposed to the identical input motion sequentially 10 times. In total nine accelerometers are installed in the model. Surface settlements are measured by laser displacement transducers. Settlements at three different depths (300, 200 and 50 mm - model scale - from the surface) are measured by settlement gauges. Measured settlements after the initial shake in prototype scale show agreements between the two models when the intensity of shaking is nearly identical.

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Other Link： http://hdl.handle.net/2433/161854

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

DOI： 10.3208/sandf.51.1091

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Language：English   Publisher：Japan Society of Civil Engineers  

This paper presents the results of a numerical investigation conducted to study the effect of vertical loads on lateral response of a free head and a capped pile group in sand. A coupled soil-pile system is idealized through 2D finite elements with soil models idealized by a hyperbolic type multiple shear mechanism. The analysis focuses on the five piles in the middle row of a 3x5 pile group spaced at 3.92-pile diameters. The interaction between a pile and the surrounding soil in the 3D type is idealized in the 2D analysis using soil-pile interaction springs with a hysteretic non-linear load displacement relationship. The presence of vertical loads on free head piles increases the confining pressures in the sand deposit confined by the piles but the rate of increase in those outside the group is relatively small, resulting in the difference in a balance of lateral soil pressures acting at the back of and in front of individual piles. A vertical load applied to a group pile with a uniform vertical displacement of 0.1 pile diameter decreases the lateral resistance of the leading pile (pile 1) by 10 % and increases the lateral resistance of piles 3 and 5 by 14 and 35 %, respectively. The same trend with higher percentages of increase or decrease is observed in the capped pile group case.

DOI： 10.2208/jscejam.67.I_271

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

DOI： 10.1139/T10-026

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

DOI： 10.1785/0120090301

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Language：English   Publisher：wiley  

DOI： 10.1002/nag.899

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A series of centrifuge model tests are conducted under the scheme of the modeling of models technique to find issues on the generalized scaling law for dynamic centrifuge tests (Iai et al., 2005). In a series of dynamic tests on a flat, saturated sand layer of 1/100 scale, four different centrifugal accelerations from 5 g to 70 g are employed on the scaled models for which the prototype is uniquely given. The models are exposed to sinusoidal input accelerations with 0.65 Hz and amplitudes of 2.5 m/s2 and 3.1 m/s2 in prototype scale. For response during shaking, nearly identical accelerations and excess pore-water pressure buildups are recorded for all the cases in the prototype scale. Discrepancies are found on surface settlements and duration time for dissipation of excess pore-water pressure. The major causes of the discrepancy may be (1) the duration time for the initial consolidation, (2) small value of the shear modulus due to low confining stress in model ground under low centrifugal acceleration, and (3) reduced permeability due to adsorption of viscous fluids on sand particles.

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Language：Japanese  

Results of site investigation after the 2011 off the Pacific coast of Tohoku Earthquake occurred on March 11 , 2011 are reported. The investigation focused on port faclities, river dykes, andliquefaction-induced damages in the northern Miyagi prefecture and Ibaragi prefecture. Substantial damage caused by liquefaction was found as well as damage caused by the tsunami.

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Other Link： http://hdl.handle.net/2433/149602

Language：English  

A series of systematic centrifuge tests is conducted in order to study the seismic response of end bearing single piles embedded in a dry dense sand layer and supporting single or double degree of freedom structures. The model is excited with and without structures using 12 sinusoidal waves as input base accelerations with constant amplitudes of about 1.5 m/s2 and varying frequencies ranging from 1 to 12 Hz. All the tests are conducted with the centrifugal acceleration of 40G. The obtained results provide a clear insight as to the distinct role of inertial and kinematic interactions as well as the combined effect of these two interactions on the motion of the pile head by identifying the fundamental frequencies that dominate the response not only for single degree of freedom structure but for double degree of freedom as well. The role of the frequency content of the input motion on the development of kinematic and inertial dynamic pile bending is also investigated.

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Other Link： http://hdl.handle.net/2433/151066

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The strain space multiple mechanism model idealizes the behavior of granular materials based on a multitude of virtual simple shear mechanisms oriented in arbitrary directions. These mechanisms idealize the internal (or micromechanical) structure of granular materials with induced anisotropy and form a second order fabric tensor, which relates macroscopic strain to macroscopic stress. Within this framework, the strain space fabric is defined as a projection of the macroscopic strain field onto an individual virtual simple shear mechanism oriented in arbitrary directions and represents the measure of mobilization of micromechanical strain due to the relative displacements between the particles. The strain space fabric, which is shaped like a four leaf clover in two dimensions, induces another fabric in stress space through a hyperbolic function, which governs the virtual simple shear mechanisms. Comparison with Discrete Element Method (DEM) simulation suggests that the strain space multiple mechanism model has the potential to capture the essential features in the evolution of an induced fabric in granular materials.

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Other Link： http://hdl.handle.net/2433/151068

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

DOI： 10.1785/0120080196

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Seismic response of end bearing piles supporting simple structures founded on a homogeneous dense sand layer over rigid rock is studied using a geotechnical centrifuge at DPRI-KU. Experiments are carried out under the centrifugal acceleration of 40G. The pile foundation is excited by a shaking table at the pile tip with and without the superstructure using sinusoidal waves with different amplitudes and different frequencies to investigate the inertial effect of the superstructure on the pile response. Nonlinear dynamic analyses using the 2-D finite element (FE) method are compared to the recorded responses during shaking in the centrifuge. The soil-pile interaction in 3-D is idealized in 2-D type using soil-pile interaction springs with hysteretic nonlinear load displacement relationships. Computed time histories of pile head acceleration and displacement, except for bending moment, were consistent with those obtained from experiments. Numerical analysis tends to under-estimate the maximum value of the bending moment, because of the empirical procedure for the setting of soil-pile interaction springs.

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Other Link： http://hdl.handle.net/2433/129397

Language：Japanese   Publisher：社団法人地盤工学会  

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10419628

Language：Japanese   Publisher：地盤工学会  

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DOI： 10.1061/40975(318)138

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Uplifting of sewage manholes is one of the typical and striking damage pattern observed in the area being hit by large earthquakes. A simplified method to estimate the maximum uplift displacement of a manhole and settlements of backfill soil under liquefaction is derived based on the mechanism of uplift of a manhole under undrained condition of backfill soil. The method is capable of evaluating effectiveness of countermeasures against uplift by considering excess pore water pressure ratio and/or unit weight of backfill soil. In the present study, the applicability for the case without countermeasures is investigated through comparison with experimental results. Results show that measured uplift displacements and settlements are within the range predicted by the proposed method.

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Other Link： http://hdl.handle.net/2433/129311

Language：Japanese   Publisher：沿岸技術研究センター  

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Many types of damage of buried structures occur due to liquefaction during an earthquake, such as flotation, settlement, bending and buckling of buried pipes. Among those, this paper focuses only on uplift of sewerage manholes. Uplift behavior of buried structures with and without a measure for uplift is investigated in model tests which are dynamically tested in a centrifuge modeling. In this study, effectiveness of the new measure for uplift which is to dissipate the excess pore water pressure is investigated to mitigate uplift displacement of the manhole during earthquakes (Konishi et al. 2008). The measure consisted of two configurations which are a filtering net and pipe. The tests showed that the mechanism of the uplift behavior and the effects of the measure for the uplift, but the uplift amount may be still too large (8% of the length of the manhole) when it is applied in practice.

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Other Link： http://hdl.handle.net/2433/129307

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1061/40975(318)198

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

Uplifting of sewage manholes is one of the typical and striking damage pattern observed in the area being hit by large earthquakes. A simplified method to estimate the maximum uplift displacement of a manhole and settlements of backfill soil under liquefaction is derived based on the mechanism of uplift of a manhole under undrained condition of backfill soil. The method is capable of evaluating effectiveness of countermeasures against uplift by considering excess pore water pressure ratio and/or unit weight of backfill soil. In the present study, the applicability for the case without countermeasures is investigated through comparison with experimental results. Results show that measured uplift displacements and settlements are within the range predicted by the proposed method.

DOI： 10.2208/journalam.11.587

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A large earthquake occurred (Mj 6.8, D=17km) at 10 : 13 AM on July 16, 2007 in Chuetsu region, Niigata, Japan. The epicenter was located offshore of Kariwa village and Kashiwazaki city. Preliminary results of the source inversions indicate a reverse fault with the NE-SW (strike : 34, Dip : 51, Rake : 74 degrees). The instrumental JMA seismic intensity was 6+ (IX in MMI) in Kariwa village, Kashiwazaki city, Nagaoka city in Niigata prefecture, and lizuna-machi in Nagano prefecture. Eleven people were killed, more than 1, 813 were injured, and more than 10, 000 were evacuated (as of 7/23/07, Niigata Prefecture). The number of totally collapsed houses was 961 in Niigata. Major lifelines, gas, water, and electricity, have been damaged and suspended for more than a day. In Kariwa village, one of the world largest nuclear power plants (7 reactor's total 8, 200, 000kW) reportedly suffered damage due to unexpectedly large strong shaking.

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10752269

Language：Japanese  

A major earthquake (Mj 6.9, 37°13.2'N, 136°41.1'E, Depth 11km) occurred on March, 25, 2007, at 9:42PM (local time) near Noto Peninsula, Ishikawa Prefecture, Japan. The JMA seismic intensity of 6+ was recorded in Wajima city, Nanao city, and Anamizu-Machi. One person was killed, more than 318 were injured. The number of totally collapsed houses were nearly 600, and partially collapsed houses exceeded 1,200 (as of May 9, 2007). Strong shaking triggered damage of lifeline systems, road embankments, settlements and tilting of port facility, and slope failures of cliffs near the sea. This paper mainly reports characteristics of strong shaking, and damage on roads and port facility.

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Other Link： http://hdl.handle.net/2433/171970

Language：Japanese   Publisher：The Japanese Geotechnical Society  

A destructive earthquake (Mw 6.6) occurred on December 26, 2003, at 7:56GMT (5:26AM local time), near the city of Bam located southeastern part of Iran. To investigate local site effects observed in the first reconnaissance, second investigation was conducted with seismic refraction method to study the relationship between surface ground condition and damage distribution. Results show that variation of P wave velocity structure near the ground surface may have some influence on damage distribution in the city.

DOI： 10.3208/jgs.2.51

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Numerical analysis for interaction between soil and pile group is performed using finite element method with 2D modeling. Results of numerical analysis are compared with the full-scale statnamic test of a 3 x 5 pile group conducted in the Salt Lake City International Airport site. In the numerical analysis of the pile group, there are two cases. The first case is that dynamic loads without cycle static loads. The other is that static loads prior to dynamic loads were applied at the group pile. In results, load versus deflection curves and bending moment versus depth are compared with the measured ones. Also, when numerical analysis includes the static loading before the dynamic loading (Case 2), the load-deflection curves were larger than measured ones but agree better than that of Case 1.

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Other Link： http://hdl.handle.net/2433/73396

Language：English   Publishing type：Research paper (international conference proceedings)  

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The paper proposes a new stress-dilatancy relationship that will be incorporated into a strain space multiple mechanism model for cyclic behavior of sand. The proposed relationship is based on the hypothesis that the dilative component of dilatancy represents the mechanism that consumes no energy, whereas the contractive component of dilatancy is in proportion to the cumulative shear strain. An example of cyclic behavior of sand simulated by the proposed model is given to demonstrate the capability of the model.

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Other Link： http://hdl.handle.net/2433/73402

Language：Japanese   Publisher：土質工学会  

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Language：English   Publisher：Japan Society for Natural Disaster Science  

One of the largest earthquakes in our history occurred at 7:58AM (local time) on December 26 2004, off the west coast of Northern Sumatra Island, Indonesia (M_w 9.3). The earthquake triggered a huge tsunami along the coastlines of the Indian Ocean and caused a huge number of casualties. From March 1 to 6, 2005, reconnaissance was conducted in the region of Banda Aceh and Meulaboh, Indonesia, where strong shaking and tsunamis were observed. The primary objective of reconnaissance was to investigate and record damage mainly due to strong motions and to estimate the seismic intensity in the region. This paper reports on the damage to earth structures, waterfront structures, and roads washed away by tsunamis. Eyewitness evidence of liquefaction in Banda Aceh, about 250 km away from the epicenter, was likely caused by the strong shaking of M_w 9.3. In Kuala Bubon village located about 15 km north of Meulaboh, settlements of embankments attached to bridge abutments collapsed just after the earthquake and before the arrival of the tsunami, so villagers could not use motorcycles or bicycles to evacuate. Lessons must be learned from this devastating earthquake, and disaster mitigation improved.

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A major earthquake (M 6.8, 37.289 N, 138.870E, Depth 13km) occurred on October 23, 2004, at 5 : 56PM (local time) near Ojiya City, Niigata Prefecture, Japan. The JMA seismic intensity of 7 was recorded in Kawaguchi-machi for the first time after seismic intensity meters were installed. Aftershocks with the JMA seismic intensity scale of more than 5 minus had been measured for more than two weeks in the affected area. Forty people were killed, more than 4,500 were injured and more than 100,000 were evacuated for days. The number of totally collapsed houses exceeded 2,800. Strong shaking triggered more than 1,600 landslides, and some of them blocked up river channels in mountain area. The earthquake also caused major damage on civil structures. The Joetsu Shinkansen bullet train was derailed for the first time in its history of 40 years. The number of passengers was 151 and miraculously no one was injured.

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10751915

Publisher：Japan Society of Civil Engineers  

Behind the damage due to the devastating tsunami after the 2004 Sumatra-Andaman earthquake, it was not clear how much damage was caused by the strong motion of magnitude 9.3 earthquake. To investigate this reconnaissance was carried out after two months of the event. Damage to the ground including liquefaction, earth structures, and port facility are reported. The investigated areas were Banda Aceh and Meulaboh where the closest city from the epicenter in west coast of the Sumatra Island.

DOI： 10.11532/proee2005.28.211

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Publisher：Japan Society of Civil Engineers  

The paper reports a series of centrifuge model tests on uplift behavior of manhole in liquefiable deposit. A total of six cases of model tests are reported where density of the model deposit and intensity of input accelerations are varied. Measured excess pore water pressures around the manhole model are used for computing safety factor against the threshold level for uplift. The computed safety factor and the degree of measured uplift are not consistent with each other, implying that deformation analysis such as through finite element method may be important to evaluate the degree of uplift of manhole in liquefiable deposit.

DOI： 10.11532/proee2005.28.4

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Dynamic centrifuge tests under 50 G and effective stress analyses (FLIP) were conducted to study the dynamic behavior of an embankment whose prototype height is 3 m. The embankment made of dry sand was constructed on the saturated sand layer whose relative density was adjusted to either 30% or 70%. Sinusoidal input motions with three different levels of peak acceleration amplitude were given. Objective of the study is to investigate the relationship between the magnitude of settlements and the peak amplitude of input acceleration.

DOI： 10.11532/proee2005.28.37

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Language：Japanese   Publisher：Disaster Prevention Research Institute Kyoto University  

Two dimensional model tests are performed on a horizontal cross section of a soil-pile system in a pile foundation. The objective of the model tests is to evaluate local soil displacement field in the vicinity of the piles associated with a global displacement of soil around the pile foundation. Two dimensional effective stress analyses in horizontal plane are also performed to generalize the findings from the model tests. An effective stress model based on multiple shear mechanism is used through a computer code FLIP. In dry condition, displacement vectors are directed away from pile front, and displacement at pile side rapidly decreases with an increasing distance from soil pile interface. In undrained condition, displacement field shows vortexes at pile side associated with push-out/pull-in pattern of displacements in front of and behind the pile. Distribution of local soil displacement between piles shows high strain concentration at soil-pile interface.

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Other Link： http://hdl.handle.net/2433/26627

Language：Japanese  

A destructive earthquake (M_W 6.6) occurred on December 26, 2003, at 7:56 GMT (5:26AM local time), near the city of Bam located southeastern part of Iran. There is the Bam fault just 2 km away from the city, which might be activated for the first time in several thousand years. The focal depth is estimated to be 8 to 10 km and the focal mechanism is reported to be dextral strike-slip with small vertical component. Strong motions were recorded in the city, about 14 km from the epicenter. The maximum peak ground acceleration was 1.0g in vertical, and 0.81g and 0.65g in horizontal components. The number of victims due to the earthquake exceeded 40,000 as of Feb. 26, 2004. A major cause of death could be crashed or hit by the debris while sleeping due to the collapse of housings. The earthquake also destroyed the historical mud brick complex, "Arg-e-Bam" which is more than 1,500 years old.

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Other Link： http://hdl.handle.net/2297/23573

Language：English   Publisher：Disaster Prevention Research Institute Kyoto University  

Effective stress analyses are performed on seismic response of underground structures subjected to strong earthquake motions. The model of sand used for the analysis is based on the multiple shear mechanism. The seismic response data analyzed are based on the 30g centrifuge tests of an underground reinforced concrete (RC) box culvert, 9 m high and 12 m wide, buried at the bottom of saturated and dry model ground 16 m deep in prototype scale. Subject to a strong earthquake motion with a peak acceleration of 0.8 to 0.9g in prototype scale, earth pressures acting on the sidewalls of the RC structure increased after shaking in both saturated and dry model grounds. These earth pressures together with the effect of the lateral displacement due to shaking result in yielding of the side RC walls. The portion of the RC walls that are put into yielding is larger in saturated model ground than in dry model ground. The effective stress analyses are capable of capturing the essential features of the response of underground structures.

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Other Link： http://hdl.handle.net/2433/26518

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Results of a series of centrifuge experiments to study the dynamic response of pile foundations under lateral spreading were compared to the results of numerical analysis. Experiments were carried out under the centrifugal acceleration of 40 G. Piles in the model foundation were lined up 3 by 3 pattern with a spacing of three pile diameter, and both pile head and bottom were rotation fixed. Piles were placed in the inclined ground of saturated sands and applied lateral loads due to the ground deformation. The effective stress finite element analysis was conducted to simulate these experiments. Computed time histories of pile head acceleration and displacement were consistent with those obtained from experiments. However, much smaller surface ground deformation in simulation might cause small amplitude of bending moments. Some calibration in the numerical modeling may be required to have more consistent results on bending moments.

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Urban development rapidly expanding from lowland to surrounding hills and mountains poses increasing risks in geo-hazards, including liquefaction during earthquakes, and failure of artificial and natural slopes. Objective of this study is to develop methodologies for assessing vulnerability to these hazards, and technologies for improving the performance of geotechnical works in urban areas. This paper summarizes the results of the study with respect to (1) performance of retaining walls at waste fill in waterfront areas, (2) hazard mapping of natural slope failures through monitoring using laser scanners, and (3) hazard assessment of residential areas in valley fills and hills.

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Other Link： http://hdl.handle.net/2433/129023

Language：Japanese  

Centrifuge experiments of static and dynamic lateral loading of pile group are carried out. Asteel pipe whose diameter is 30 cm and length 10 m is scaled down to 1/20 for static tests, and1/40 for dynamic tests. It is experimentally shown that in the dynamic tests the hysteresis loopof inertial force and displacement at the pile head becomes elliptical due to the phase differencebetween pile and the ground, and/or the nonlinear property of sands. Even in the case ofdynamic tests under saturated condition, group pile behavior may be observed.

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Other Link： http://hdl.handle.net/2433/129251

Publisher：The Japanese Geotechnical Society  

DOI： 10.11512/jiban.JGS38.0.1441.0

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DOI： 10.1007/978-3-030-22818-7_7

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Language：Japanese   Publisher：電気評論社  

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Other Link： http://hdl.handle.net/10112/10712

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Kumamoto earthquake occurred in Kyushu Island, which is located at the south part of Japan, at 1:25 am on 16th April in 2016. The magnitude of the biggest earthquake was M7.3 and a lot of buildings and civil structures were damaged and collapsed due to the shaking generated by the sliding active fault overlain across the middle part of Kyushu Island. This paper shows the report of the site investigation performed at Mashiki-machi, Nishihara-mura and Minamiaso-mura in the term of 7th-8th in May.

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Other Link： http://hdl.handle.net/2433/217308

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Other Link： http://hdl.handle.net/2433/171967

J-GLOBAL

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DOI： 10.3233/978-1-60750-031-5-1251

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Applicability of the two stage scaling relationship called generalized scaling law for centrifuge tests proposed by Iai et al. (2005) is investigated for dynamic response of flat layered media. In this scaling law, recorded physical model parameters are, firstly, converted to those in the virtual 1G field with scaling factor for centrifuge model tests, η. Then the parameters are further converted to prototype with scaling factor for 1G tests, μ (Iai, 1989). By using this scaling law, model tests with scaling factor (prototype/physical model) of 100 or much higher may be possible without encountering problems, e.g., scaling of granular material. The generalized scaling law in centrifuge modeling is investigated through dynamic response of compacted sand. In the experiments, a prototype is scaled down to 1/100 with 9 combinations of scaling factors of virtual 1 G and centrifugal field. Input motions are also scaled accordingly. Then the generalized scaling relation is applied to examine responses in the prototype scale. Responses compared in the present study are shear wave velocity, displacement, and acceleration. If the generalized scaling law is valid, these responses in the prototype scale are identical regardless of scaling factors. Results confirm the validity of the scaling relation of these physical parameters in a range of 40 G to 70 G of centrifugal accelerations. © 2009 IOS Press.

DOI： 10.3233/978-1-60750-031-5-664

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Applicability of the two stage scaling relationship called generalized scaling law for centrifuge tests proposed by Iai et al. (2005) is investigated for dynamic response of flat layered media. In this scaling law, recorded physical model parameters are, firstly, converted to those in the virtual 1G field with scaling factor for centrifuge model tests, η. Then the parameters are further converted to prototype with scaling factor for 1G tests, μ (Iai, 1989). By using this scaling law, model tests with scaling factor (prototype/physical model) of 100 or much higher may be possible without encountering problems, e.g., scaling of granular material. The generalized scaling law in centrifuge modeling is investigated through dynamic response of compacted sand. In the experiments, a prototype is scaled down to 1/100 with 9 combinations of scaling factors of virtual 1 G and centrifugal field. Input motions are also scaled accordingly. Then the generalized scaling relation is applied to examine responses in the prototype scale. Responses compared in the present study are shear wave velocity, displacement, and acceleration. If the generalized scaling law is valid, these responses in the prototype scale are identical regardless of scaling factors. Results confirm the validity of the scaling relation of these physical parameters in a range of 40 G to 70 G of centrifugal accelerations. © 2009 IOS Press.

DOI： 10.3233/978-1-60750-031-5-664

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A new formulation of elastic body is proposed in order to consider the geometric nonlinearity due to large deformation and rotation. The formulation is based on the concept of the multiple shear mechanism and the relationship between the volumetric strain and the isotropic pressure is assumed to be linear and so is the relationship between the virtual simple shear strain and the virtual simple the shear stress. The constitutive model is introduced to a finite element program by the Total/Updated Lagrangian Formulation. Some examples simulated by the program are given to demonstrate the capability of the model.

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Other Link： http://hdl.handle.net/2433/129308

Language：English   Publisher：AMER INST PHYSICS  

A simplified method to estimate the maximum uplift displacement of a manhole and settlements of backfill soil under liquefaction is proposed. The method is derived based on the mechanism of uplifting of a manhole under undrained condition of backfill soil. It also has a capability of estimating effectiveness of countermeasures against uplifting by considering excess pore water pressure ratio and/or unit weight of backfill soil. In the present study, however, estimation for the case of no countermeasure is verified through comparison with experimental results. Results show that measured uplift displacements and settlements are confined within the boundary predicted by the proposed method.

DOI： 10.1063/1.2963871

Web of Science

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Language：English   Publisher：AMER INST PHYSICS  

A simplified method to estimate the maximum uplift displacement of a manhole and settlements of backfill soil under liquefaction is proposed. The method is derived based on the mechanism of uplifting of a manhole under undrained condition of backfill soil. It also has a capability of estimating effectiveness of countermeasures against uplifting by considering excess pore water pressure ratio and/or unit weight of backfill soil. In the present study, however, estimation for the case of no countermeasure is verified through comparison with experimental results. Results show that measured uplift displacements and settlements are confined within the boundary predicted by the proposed method.

DOI： 10.1063/1.2963871

Web of Science

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Finite strain (large deformation) formulation is presented for a multiple mechanism model for idealizing the behavior of sand. The model is capable of representing non-linear behavior of sand under transient and cyclic loading, including the phenomenon of liquefaction. In the finite strain formulation, isotropic and isochoric components will be separated based on the approach adopted for hyper-elastic materials.

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DOI： 10.1193/1.2790490

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Physical model tests under centrifugal acceleration are conducted and results are compared with the one obtained by a finite element analysis. When the lateral movement of the sheet pile head is fixed during the self-weight analysis in simulation, that is the same condition as the model tests, computed bending moments due to consolidation agree with measured ones and also deflections after shaking are generally consistent with each other. While if the pile head is free in the self-weight analysis, computed bending moments and deformations disagree with measured ones. Thus, to simulate an existing sheet pile wall behavior during large earthquakes with accuracy required in practice, it is necessary to obtain in-situ bending moment profiles and input them as an initial condition.

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Other Link： http://hdl.handle.net/2433/73397

Language：English  

To investigate the generalized scaling relation in centrifuge modeling, a prototype is scaled down to 1/100 with 9 combinations of scaling factors of virtual 1 G and centrifugal field. The model ground is flat and made of a homogeneous sand layer. Five accelerometers are employed in various depths. Dynamic input motions are scaled accordingly. In prototype scale, the applicability of the scaling relation is evaluated by examining the identity of dynamic responses obtained from 9 cases. Results show that shear wave velocities are approximately the same value and, therefore, the generalized scaling relation of shear wave velocity is confirmed. For the scaling relation of acceleration, when the ground response is nearly elastic, the scaling law is confirmed for a range of centrifugal acceleration applied in this study.

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Publisher：Disaster Prevention Research Institute Kyoto University  

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Dynamic behavior of an embankment (3 m height) made of dry sand underlain by saturated sand deposit with 5 m depth are studied. Firstly, centrifuge experiments under 50 G are conducted. The relative density of saturated sand deposit is approximately either 30 % or 70 %. Sinusoidal input motions with various levels of peak acceleration amplitude are employed. Test results show that the maximum settlement was 1.4 m and 0.09 m, respectively, for loose and dense deposit. The amount of settlements for dense deposit are found to be proportional to the peak amplitude of input acceleration, while it may have a plateau for the case of loose deposit with increase of input acceleration amplitude. Following the centrifuge experiments, an effective stress analysis is carried out with the same prototype dimension of the experiments. The numerical analysis simulates well deformations and transient motions of the experimental counterparts. It is found that, in the analysis for loose deposit, when input acceleration increased, non-liquefied area underneath the embankment became large, causing larger non-liquefied wedge pushing liquefied soils aside.

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Other Link： http://hdl.handle.net/2433/26628

J-GLOBAL

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J-GLOBAL

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DOI： 10.11512/jiban.JGS39.0.1789.0

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DOI： 10.11512/jiban.JGS39.0.1529.0

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Language：English  

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Language：English  

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Language：Japanese  

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Language：Japanese   Publisher：自然災害科学会  

CiNii Books

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Other Link： http://id.nii.ac.jp/1141/00113530/

Language：Japanese   Publisher：自然災害科学会  

CiNii Books

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Other Link： http://id.nii.ac.jp/1141/00113410/

Language：English  

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Language：English  

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Language：Japanese   Publisher：The Japanese Geotechnical Society  

DOI： 10.11512/jiban.JGS38.0.1443.0

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Language：Japanese  

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

Shaking table tests and the three dimensional distinct element analyses were carried out to investigate the rotation response of tomb stones, which are excited by seismic motion. It is clarified that rotation response of a rigid body is caused by two reasons, one is the rocking caused by one directional input motion and the other is caused by the rotation of particle motion of input motion. The rotation response of a real tomb stone was simulated using the accerelation record observed during 1994 Sanriku-Haruka-Oki Earthquake. It is concluded that, except for special cases, the direction of rotation of a rigid body represents the reverse rotation direction of particle motion of seismic motion.

DOI： 10.2208/jscej.1998.598_287

CiNii Books

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