Research On The Formation Mechanism And Stability Of Old Landslide In Loess Plateau

Since the reform and opening up, China’s economic development has entered a stage ofrapid development, people enjoy achievements economic development, it is also to bringsome of the geological environment disasters. In recent years, as one of several importantgeological disasters, the landslide is constantly rising every year hundreds of proportion, withmore intense human activity, coupled with the impact of human factors, making suchdevelopment of increasingly serious disasters and hazards seriously restricts thetransformation of economic development and the backwardness of the disaster area.In this paper,we take the qinghua temple landslide which is in the town of yaodian inBaoTa district as the research object. On the basis of analyzing landslide formation based onthe geological environment background conditions, influencing factors on the stability oflandslide is analyzed, then the numerical simulation software is used to simulate the formationmechanism of landslide disaster, and adopt the method of qualitative analysis and quantitativecalculation, the stability of the landslide are studied, obtained the following main results:1.Qinghua temple landslide is an old landslide, influenced by rainfall and humanengineering activities, the landslide happened locally quadratic sliding, and in the oldlandslide (grade I) formed levelⅡ landslide of south and north sides. Level I, Ⅱ landslideslope on the secondary development of scarp, scarp at all levels and leading edge aven, smallgully and the development of cracks, sliding devices for flange and scarp front at variouslevels are local slump, etc2.Using sensitivity analysis method, to determine the factors affecting the stability ofQing temple landslide, it is concluded that the results are as follows: Groundwater level>Load> internal friction angle>cohesion> landslide density> earthquake, which groundwaterand the load factor is the most sensitive.3.Through the formation of Qing Temple landslide causes of qualitative analysis, basedon the finite element software for Qing Temple landslide formation mechanism simulationstudy,the formation of landslides experienced: the lower push deformation, sliding middlebedding upper crack subsidence, comprehensive analysis of the landslide passage ceremonyfor the loess landslides. 4.We use the limit equilibrium and software Midas/GTS methods for landslide’s stabilityanalysis,getting the results: before excavating toe of the slope, the overall landslide is stableunder natural state and under full water conditions,the landslide’s stability is significantlyreduced, but the most is stable, local is in the unstable and basic stable state; After excavatingtoe of the slope, the overall landslide slope is still in the stable state, but the partial is in anunstable state and stable but not safety in the natural state. Under full water conditions, thelandslide is in a state of instability and insecurity.In addition, the use of finite elementsoftware Midas/GTS Qing Temple landslide on the finite element numerical simulation resultsshow that: in front of the leading edge of the excavation of the landslide, the slope edge,central large deformation in landslide on has been formed through the partial sliding surfacecompletely;in the excavation of the toe, the stress mainly in the excavation, forming a largedifference between the stress surrounding slopes, prone to damage deformation.