The Formation Mechanism And Stability Evaluation Of Yanwotou Landslide In Luzhou City,Sichuan Province

Slope stability problem is very prominent in red layer which is a typical slippery stratum, a large number of landslide disasters occur among the rainy season, the occurrence of landslide and the revival of ancient landslide (local resurrection) in such formation, has been a serious threat to the safety of people’s life and property. Thus, it has important practical significance to reveal the development regularity of landslides and disaster prevention and mitigation by the study of the mechanism of landslide formation, the stability of the reactivated body at the present stage and the deformation and failure mode of slope.In July2011, Yanwotou ancient landslide occurred large-scale sliding which is developed in approximate level red beds in Luzhou City, Sichuan Province. It has made a serious threat to the safety of the life and property of residents. Taking Yanwotou ancient landslide as object of study, the formation mechanism and stability evaluation of it as the purpose of the study, tries to carry on deep analysis on it and rich research about landslide occurred approximate level red beds by using the method of analysis of geological process mechanics, the limit equilibrium method and numerical simulation method, The main research contents and results are as follows:(1) Expound the geological environmental conditions of landslide, characteristics of landslide boundary and morphology, distribution of rock and soil and the deformation and failure in detail base on detailed investigation on the geological conditions in the study area.(2) Present stability of the ancient landslide and its three reactivated body are qualitative evaluated through the analysis of deformation and failure characteristics; the formation mechanism of ancient landslide, different resurrection mechanism of the three reactivated body and its deformation and failure process revealed through analysis of the geological process mechanism.(3) The yanwotou ancient landslide HPO was formed by whole shear failure because of a major earthquake or a massive storm conditions, or the superposition of these two conditions in the history. As a result, two rift troughs were formed because of the local difference velocity of the sliding body in the sliding process.(4) The evaluation of stability on the ancient landslide and three dead body at the present stage was made by limit equilibrium method quantitatively, and the reasonable prediction on the deformation and failure modes of reactivated bodies was made by combining characteristics of deformation and failure of them.(5) Three reactivated body are simulated by FLAC3D numerical simulation software in natural, rainstorm and earthquake conditions respectively, the mechanism of deformation and failure of the reactivated body was discussed through deep analysis of simulation results.(6) The validity of the numerical simulation was illustrated because numerical simulation results are consistent with quantitative calculation based on limit equilibrium method and the deformation failure characteristics of field reactivated bodies. Based on the above conclusions, the corresponding pertinent recommendations are proposed according to the characteristics of the reactivated body.