TIME-DEPENDENT STRENGTH MOBILIZATION OF CLAY SEAMS EMBEDDED IN PROGRESSIVE ROCK SLOPE FAILURE PLANES

嵌入渐进式岩石斜坡破坏面的粘土层随时间变化的强度动员

基本信息

批准号：
13650537
负责人：
OHTA Hideki
金额：
$ 2.18万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650537/
关键词：
slope slope failure progressive failure slide failure underground water shear box tests

项目摘要

Many of the rock slope failures take place as the rock mass slide along the slip planes in which thin clay seams are embedded. It is not usually possible to carry the triaxial tests on the undisturbed thin clay seams taken from the slip planes because the thickness of the specimens is not large enough to set on the pedestal of the triaxial apparatus. The only possible way of carrying shear tests on the thin clay specimens seems to use the shear box test which traditionally considered as a minor testing method due to its simple mechanism of shear. The investigators have carried many series of shear box tests on the clay seam specimens taken from the actual rock slope failures and found that the constant volume shear box tests can give reasonable strength parameters in terms of effective stress. They have theoretically derived the method to convert the strength obtained from shear box tests into the strength obtained from triaxial tests. This was successfully utilized in the analyses of … More rock slope failures and resulted in the findings of mechanism of rock slope failures typically triggered by heavy intensive rainfall. The strength parameters to be applied to the slope failure analyses, however, were found from the back-analysis of case studies to be of zero cohesion even in the cases that some cohesion in terms of effective stress was actually observed ion the shear box tests. This zero-cohesion was eventually found to be resulted from the submersion of the clay seams undergoing the progressive rock slope failure during the period of occasional heavy rainfalls. The conclusion most important from the practical point of view is that the rainfall was found to be effective not only in inducing the driving force of slope failure by high water pressure in the slip planes but also in temporarily reducing the cohesion of the clay seams caused by submersion. This implies that we should not rely on the cohesion of the clay seams in estimating the possible factor of safety of rock slope failures. Less

许多岩石斜坡故障发生在沿着薄薄的粘土海洋嵌入的滑动平面的岩石质量滑道。通常不可能在未受干扰的薄粘土海洋上进行三轴测试，因为该物种的厚度不足以放在三轴仪的基座上。在薄粘土物种上进行剪切测试的唯一可能方法似乎使用了剪切盒测试，该测试传统上由于其简单的剪切机制而被认为是一种次要的测试方法。研究人员对从实际的岩石斜率失败取的粘土接缝标本进行了许多系列剪切盒测试，发现恒定体积剪切盒测试可以在有效的压力方面提供合理的强度参数。他们从理论上得出了将剪切箱测试获得的强度转换为从三轴测试获得的强度的方法。这是在……更多的岩石斜率故障的分析中成功使用的，并导致了岩石斜率故障机制的发现，通常是由大量强化降雨引发的。然而，从案例研究的背面分析中发现，要应用于斜率故障分析的强度参数，即使在实际上观察到有效应力方面的某些凝聚在离子方面，剪切盒测试也是零内聚力的。这种零粘合剂均匀地发现是由于偶尔大雨时期的岩石海洋浸没，经历了进行性岩石斜率失败的淹没。从实际的角度来看，最重要的结论是，发现降雨不仅在诱导的坡度驱动力中通过滑动平面中的高水压驱动力，而且还暂时降低了由淹没引起的粘土海洋的凝聚力。这意味着我们不应依靠粘土接缝的凝聚力来估计岩石斜率故障的安全性因素。较少的