Characteristics and cause analyses of the Pingzi landslide in Lianghe Town，Yiliang County，Yunnan Province

On August 25th, 2017, a landslide occurred in Pingzi Village, Lianghe Town, Yiliang County, Yunnan Province.The accumulation blocked the river and formed two dammed lakes. The author conducted a detailed geological survey on the landslide site for the first time, and combined with the aerial photography of the drone, analyzed the causes and movement characteristics of the landslide. The results show that the fundamental changes in the hydraulic properties of landslides under the effect of continuous seepage softened and increased pore water pressure. The right side of the landslide slipped along the floor and the lateral shear slip occured along the fault zone on the left side. Eventually, a bedding push occured and the landslide was a typical “wedge” slip. The fundamental caution that of the sudden sliding of the sliding body is “slippery slope” was cut，and was also one of the reasons why the middle and lower parts of the sliding body have not completely disintegrated and maintained certain structural characteristics. Landslide deposits have clear boundary lines of earth and rock,which are characterized by “multiple stacking”, and there are obvious overhead structures between blocks. The Pingzi landslide experienced three slips.The entire landslide movement process can be summarized as follows: the right bedding slip-the left “directional expansion”-“slippery slope” was cut, the landslide was overall glissade-the slide “emergency brake”-sliding body “multiple stack Stacked”.