Sliding mechanisms and fracture genesis of Jiweishan landslide in Wulong#br#
LI Xiao1，2，ZHANG Nianxue1，2，SHENG Zhuping3，LI Shouding1，2，HAO Jianming1，2#br#
(1. Key Laboratory of Engineering Geomechanics，Institute of Geology and Geophysics，Chinese Academy of Sciences，Beijing 100029，China；2. College of Earth and Planetary Sciences，University of Chinese Academy of Sciences，Beijing 100049，
China；3. AgriLife Research Center，Texas A&M University，El Paso，Texas 79927，USA)
Abstract：Because of the unique characteristics of Jiweishan landslide，it is necessary to make clear special geological environment，geological structure and geometry of failure rock masses，and mechanical properties of both rock masses and sliding plane for studying the failure mechanism of Jiweishan landslide and distinguishing from other types of rock landslides. In this paper，the stability of the sliding body and crack causes were analyzed based on detail analyses of engineering geological environment and conditions of Jiweishan landslide as well as physical and mechanical properties of rock masses. New elastic mechanics formulas for evaluating slope stability and creep compression behaviors of rock masses were derived based on geometry，geological structure and tectonic characteristics of the sliding body，distribution of karst fractures of rock masses as well as the large compression stress condition. The shear strengths of the weak sliding plane and the front side wall were calculated，and the compression amount of the sliding rock mass，i.e.，the opening width of the crack T0，was also estimated. It is revealed that T0 is an extension fissure caused by the compression of the sliding body rather than a tensile crack suggested by other literatures and that the creep sliding results from the compression of the sliding body. It is also pointed out that T1 is a tensile fissure based on the side-aligned geometric weight center of the sliding body，center-tilted compression and large lateral compression amount. Calculations by the developed formulas show that the stress and strain of the front sliding body are the highest and reach the compression strength of the rock mass，and hence，the front rock masses are broken by compression and the front side wall is also sheared off，which explains the failure cause of the sliding body. Moreover，the compression stress within different segments of the karst fractured limestone，failure stress of the front rock masses，compression amount and compression modulus and directional fracture ratio were assessed based on the formula of the elastic compression model.
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2020, Vol. 39 
