Abstract: The 2008 great Wenchuan earthquake caused multiple rapid and long run-out landslides,which resulted in a lot of deaths and property loss.Donghekou landslide,a typical rapid and long run-out landslide triggered by Wenchuan earthquake,is located in Qingchuan county,and at present,it is concerned and discussed particularly because of its complex original mechanism.Field investigations show that the original mechanisms and dynamic features mainly include the followings,for example,the shattering collapse,the horizontal slinging,the debris flow and the vibration liquefaction,etc.In order to simulate and reconstruct the vibration liquefaction,representative soils on sliding zone of Donghekou landslide were collected for soil tests.By using the advanced DPRI ring shear apparatus,a series of ring shear tests have been carried out to study the vibration liquefaction process of Donghekou landslide under the loading of real seismic waves,and some ideal results were gotten.The test results show that when the earthquake happened,the vibration liquefaction occurring on the potential sliding surface played an important role in generating the rapid and long run-out landslide.When the soils were dry,only a small displacement(0.007m)was generated,which couldn't form a landslide with high speed and long run-out;with the vibration liquefaction,the shear strength could be decreased and a large displacement could be generated,which supplied a necessary condition for the generation of rapid and long run-out landslide.

Key words: Wenchuan earthquake, rapid and long run-out landslide, ring shear test, vibration liquefaction, shear strength, shear displacement

摘要： 汶川大地震触发了多处高速远程滑坡,导致了大量的人员伤亡及财产损失。其中,东河口滑坡是这次地震触发的最为典型的高速远程滑坡之一,同时也是目前备受关注、争论颇多的滑坡之一。野外调研结果表明,该滑坡的成因和动力特征主要包括震裂溃屈、水平抛射、碎屑流化和振动液化等4个方面。为了对该滑坡滑动过程中的振动液化这一动力特征进行模拟再现,在东河口滑坡体上采集了具有代表性的滑带土作为试验样品,并以该地震时的实测地震波作为动力输入,利用目前国际上最先进的DPRI环剪试验机,对滑坡滑动过程中的振动液化现象进行了一系列环剪试验研究。结果表明,地震作用过程中,发生在滑坡潜在滑面上的振动液化现象是导致高速远程滑坡产生的一个重要因素;伴随着振动液化过程,滑体的剪切强度迅速降低并产生逐渐增大的剪切位移,为高速远程滑坡的形成提供了条件。

关键词: 汶川地震, 高速远程滑坡, 环剪试验, 振动液化, 剪切强度, 剪切位移