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Development of assessment method of flow phenomena based on undrained shear and grain crushing characteristics measurement

基于不排水剪切和谷物破碎特性测量的流动现象评估方法的开发

基本信息

批准号：
12556022
负责人：
SASSA Kyoji
金额：
$ 8.26万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12556022/
关键词：
flow phenomena sliding surface liquefaction gain crushing characteristics ring shear tests excess pore pressure landslides disaster risk assessment 災害予測

项目摘要

Flow phenomena which brought about most of the casualties in landslide disaster of these years, are caused by liquid-like state of sliding surface and serious reduction of shear resistance. Sassa et al. showed these phenomena are caused by "sliding surface liquefaction" triggered by soil grain crushing in the shear zone and volumetric shrink. This study is focused on the examination of new evaluation method of "sliding surface liquefaction potential" in order to establish methodology of assessment of extension and degree of flow phenomena, with use of geotechnical landslide simulator for earthquake-induced landslides which Sassa developed, based on the parameters of slope angle, geology, geotechnical property, depth of sliding surface, saturation degree, etc.In the fiscal year 2002 following achievements were obtained(1) Portable "Grain Crushing Apparatus" which is designed for investigate grain crushing characteristics of soil samples, was improved. Detail microstructure of lens-like … More shear zones of soil samples formed in the, sampel box of the Geotechnical Landslide Simulator for Earthquake-triggered Landslides. Rather interesting fact that the grain crushing much proceeded in the upper and lower boundaries of the shear zone(2) Shear behaviour characteristics of the soil layer in the vicinity of the potential sliding surface with use of the Geotechnical Landslide Simulator for Earthquake-triggered Landslides by applying three dimensional earthquake acceleration record on the soil samples taken from the Nikawa Landslide site which was triggered by the 1995 Hyogoken-Nambu Earthquake. In the test series, following results were obtained (a) no-sliding surface liquefaction took place in the material that which showed very little displacement although generated excess pore pressure just after the main shock ; (b) rapid-long runout can be triggered in the soil layers that which showed displacement just after mainshock due to excess pore pressure generation, because grain crushing and excess pore pressure generation causes sliding surface liquefaction(3) A new method was developed to assess excess pore pressure generation during cyclic loading in the soils taken from 1995 Takarazuka-Golf Course Landslide which was triggered by the Hyogoken-Nambu Earthquake, based on volume change due to grain crushing in the drained shear test and one-dimensional coefficient of compressibility. This method shows that drained (not undrained) constant stress test data can assess the excess pore pressure generation in the fully-saturated and undrained condition. Also it implies that the apparatus described in (1) enables sliding surface liquefaction potential measurement even in situ Less

流动现象是近年来滑坡灾害中造成人员伤亡最多的一种现象，它是由于滑面呈液态，抗剪强度严重降低而引起的。Sassa等人指出，这些现象是由剪切带中的土粒破碎和体积收缩引发的“滑动面液化”引起的。本研究的重点是审查新的评估方法“滑动面液化潜力”，以建立评估的方法学的扩展和程度的流动现象，使用岩土滑坡模拟器的地震诱发的滑坡Sassa开发，基于参数的边坡角，地质，岩土性质，深度的滑动面，饱和度，2002年度取得了以下成果：（1）改进了用于研究土样颗粒破碎特性的便携式“颗粒破碎仪”。类透镜的微观结构 ...更多信息土样的剪切带，在地震触发滑坡的岩土滑坡模拟器的样品箱中形成。（2）利用土工滑坡地震模拟试验机研究了潜在滑动面附近土层的抗剪特性，并对潜在滑动面附近土层的抗剪特性进行了分析。通过对1995年触发的尼瓦瓦滑坡现场采集的土壤样品应用三维地震加速度记录，兵库县南部地震试验结果表明：（1）在主震后产生超静孔压，但位移很小的材料发生了非滑动面液化;（B）在主震后刚发生位移的土层中，由于超孔隙水压力的产生，可以触发急长跳动，因为颗粒破碎和超孔隙压力的产生会导致滑动面液化（3）开发了一种新方法，以评估1995年宝冢高尔夫球场滑坡中土壤在循环荷载作用下超孔隙压力的产生，该滑坡是由兵库县地震引发的。南部地震，基于排水剪切试验中颗粒破碎引起的体积变化和一维压缩系数。该方法表明，排水（而不是不排水）恒定应力试验数据可以评估在完全饱和和不排水条件下的超孔隙水压力的产生。这也意味着，在（1）中描述的设备甚至能够在原位进行滑动表面液化潜力测量。