Estimation of run-out distances of slope failures during earthquakes considering effects of rainfall

土壤样本取自2004年新泻地震中发生的斜坡崩塌现场。进行了多组室内三轴试验，研究了饱和对土的残余强度的影响。研究发现，土体失稳后的残余强度受含水饱和度的影响很大，但不同土体的影响方式不同。影响这些关系的因素很多，建议按风化砂岩、风化泥岩、风化花岗岩、火山土等土壤类型进行分类，可以更好地表征土的残余强度与饱和度的关系。在以往用土体密度表征完全饱和土体流动和非流动状态的基础上，考察了饱和状态如含水率和饱和度以及状态参数如土体密度和围压对土体失稳距离的影响，并提出了一种简单的分析方法，即采用Re〓来估计地震时边坡失稳的跳动距离

The soils samples were taken from the sites of slope failures which had occurred during 2004 Niigata Chuetsu Earthquake. A multiple series of laboratory triaxial tests were conducted to examine the effects of saturation on the residual strength of soils. The residual strength of soils subjected to slope failures was found to be strongly affected by the degree of water saturation, however in a different manner among the soils. There would be many factors coming into these relations, and it is suggested that the dependency of the residual strength on the degree of saturation can be better characterized by categorizing the relations in terms of types of soils such as weathered sandstone, weathered mudstone, weathered granite, volcanic soils and others.The residual strength of unsaturated soils was also examined by using a constant-volume direct shear test apparatus. Based on the past studies characterizing the flow and non-flow conditions of fully saturated soils in terms of soil density, the influence of saturation conditions such as water content and degree of saturation as well as state parameters such as soil density and confining stress was examined.A simple analysis was proposed to estimate the run-out distances of slope failures during earthquakes by adopting the re〓