STUDY OF GEOLOGICAL ORIGIN MECHANISM OF TANGJIASHAN LANDSLIDE AND ENTIRE STABILITY OF LANDSLIDE DAM
LI Shouding1，LI Xiao1，ZHANG Jun2，HE Jianming1，LI Shihai3，WANG Yangchun4
(1. Key Laboratory of Engineering Geomechanics，Institute of Geology and Geophysics，Chinese Academy of Sciences， Beijing 100029，China；2. Chongqing Institute of Geological Environment Monitoring，Chongqing 400015，China； 3. Institute of Mechanics，Chinese Academy of Sciences，Beijing 100190，China；4. Institute of Mountain Hazards and Environment，Chinese Academy of Sciences，Chengdu，Sichuan 610041，China)
Abstract：By geological survey and engineering geological characters analysis of Tangjiashan landslide，the landslide types and geological origin mechanism are studied. On the base of the rock mass structure analysis and surface displacement monitoring，the entire stability of landslide dam is studied. The conclusions are achieved：(1) Tangjiashan landslide is of high speed rock slide triggered by earthquake，and is located in a consequent slope of complex overturned fold. Landslide sliding zone is possibly situated in interbedded shear zone. (2) Landslide dam material is mainly block rock mass overlying with weathered incompact accumulation，and entire stability is good. Flood affected the surface displacement of landslide dam with the maximum displacement of 140 mm. Increment of surface displacement is down after flood，and landslide dam is stable now. (3) The chained hazard study of earthquake landslide→dammed lake→breach→flood with domino effect should be emphasized. Engineering geological survey and seismic risk study of slope are included interbedded shear zone.
