The Formation Mechanism And The Evaluation Of Stability Of Caiziwan Landslide In Muli Of Sichuan Province

The zone of Xiamaidi County of Mu Li in the southwest of Sichuan province is a steep terrain. The relative elevation is nearly 1 kilometers. It belongs to the high mountains area. The lithology is variable,there are a lot of Faults,Physical geological effect is intense.And it is a prone areas of natural geological disaster.the caiziwan landslide in this area is a large overburden landslide which developed in colluvial deposits and eluvial material.Its volume is almost 260 m3. The design department decided to use tunnel to cross this landslide. The formation and evolution mechanism of the landslide and the deformation of the existing slope determined whether the establishment of the tunnel project is right, so carry out special investigation and research work of the landslide and the existing slope is necessary. This paper take the landslide as the research object.By detailed Surveying and mapping investigation of The phenomenon of deformation and failure, by the use of he chemical composition of red clay of the surface area of landslide the test of the surface morphology of quartz particle characteristics, combined with the geological conditions of the landslide area, established the numerical calculation model, reduced the landslide evolution mechanism and the deformation of slope stability condition were evaluated by limit equilibrium method and strength reduction method. Get the conclusion as follows:1.Determined the zone of deformation or failure(The lateral sliding region of the lower part, The sliding disintegration of central region, the sliding collapse region of the upper region, the disintegrate scour area of the back region) and associated damage combinations: posterior regions mainly by ditch water caused by scouring, affected by beneath the sliding body deformation caused by the upper area, the lower lateral sliding zone substance is in the central sliding collapse area and the big volume clay slip away, lateral result from either side.2. The lower sliding zone in the left and right sides of the landslide boundary clay migration is caused by the collapse of the cladding material.3. The landslide formation evolution experienced three stages: a huge landslide slump concave cavity to the lower lateral sliding formed early, lock, residual reentrant above slump back step by step, and overlap in lower part;4. Early landslide formed step by step backward. Forming time is after rapeseed groove, the 70 s last century. The scale is almost million level;5. The limit equilibrium method results show that the deformation under the condition of natural slope basically stable, the result of condition of heavy rain is unstable; the results of strength reduction show that with the shear parameters weakening, the development trend of plastic zone are well versed in, safety coefficient is less than the need of safty.With the deformation of landslide, without the effective support measures, the landslide will develop to instability in the future. For reconstructing highway roads safe through the landslide area, we must take effective support or use hence line around.