Observation of shear zone development in ring-shear apparatus with a transparent shear box
Observation of shear zone development in ring-shear apparatus with a transparent shear box
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DOI：
10.1007/s10346-006-0043-2
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发表时间：
2006-09-01
期刊：
影响因子：
6.7
通讯作者：
Sasaki, Ryo
中科院分区：
文献类型：
--
作者：
Fukuoka, Hiroshi;Sassa, Kyoji;Sasaki, Ryo
采用新型透明剪切盒环剪仪和视频图像分析系统，对粗粒硅砂进行了排水和不排水速度控制试验，研究了颗粒材料剪切带的形成过程。利用粒子图像测速（PIV）软件对视频图像进行处理，观测了环剪试验中不同阶段颗粒在剪切作用下的速度分布。观察剪切过程中剪切区厚度和剪切模式类型（滑动状或流动状）。在低速排水条件下达到峰值强度之前，上部剪切盒中的相对大部分样品显示出结构变形和破坏行为的速度分布轮廓。在峰值强度之后，速度分布变为滑动状模式，此后几乎没有变化。在排水和不排水条件下的高速试验中，与低速试验相比，观察到几乎类似滑动的模式。高速试验的表观剪切区厚度比低速试验薄。出乎意料的是，几乎没有观察到差异的剪切区厚度和剪切模式（滑动或流动状）之间的排水和不排水测试。这项研究是作为国际滑坡联合会（ICL）的国际滑坡计划（IPL）M101“地震和降雨引起的快速和长距离流动现象（APERITIF）的区域预测”的一部分进行的。这些研究结果将有助于了解剪切带的发展机制，作为一个基础知识，快速长径流滑坡灾害风险缓解的粒状材料。
Using a new ring-shear apparatus with a transparent shear box and video image analysis system, drained and undrained speed-controlled tests were conducted on coarse-grained silica sands to study the shear-zone formation process in granular materials. Velocity distribution profiles of grains under shear at various stages in the ring shear tests were observed through processing the video image by the Particle Image Velocimetry (PIV) program. Shear-zone thickness and type of shear mode (slide-like or flow-like) during shear were observed. Before reaching peak strength in low-speed and drained condition test, a comparatively major part of the sample in the upper shear box showed a velocity distribution profile of structural deformation and dilatancy behavior. After peak strength, the velocity profile changed into a slide-like mode and thereafter showed almost no change. In higher speed tests with drained and undrained conditions, an almost slide-like mode was observed, compared to low-speed test. Apparent shear-zone thicknesses of high-speed tests are thinner than low-speed tests. Unexpectedly, almost no difference was observed in the shear-zone thickness and mode of shear (slide or flow-like) between drained and undrained tests. This study was conducted as part of the International Programme on Landslides (IPL) M101 "Areal prediction of earthquake and rain induced rapid and long-traveling flow phenomena (APERITIF)" of the International Consortium on Landslides (ICL). These results will contribute to understanding the mechanism of shear-zone development in granular materials as a basic knowledge for disaster risk mitigation of rapid long run-out landslides.