Study On Sliding Mode And Deformation Law Of Bedding Rock Landslide With Double Weak Interlayers

The bedding rock landslide with weak interlayer is one of the main ways of rock slope failure,and it is also the type of landslide that accounts for the largest proportion of large landslides.The geological environment,rock stratum structure,topography and surrounding human activities of bedding rock landslides are quite different,resulting in various sliding patterns and complex deformation and failure mechanisms.Previous studies mainly focused on single-stage sliding mode controlled by single weak interlayer,but in nature,bedding rock landslides are often affected and controlled by double or multiple weak interlayers.Aiming at this feature,based on the detailed classification and summary of weak interlayer and bedding rock landslide,this paper discussed the case of the bedding rock landslide in the Lvliang Mountain of Shanxi.The landslide sliding mode and sliding process of bedding rock landslide under different mechanical conditions are analyzed.The factors affecting the stability,deformation law and failure mechanism of single weak interlayer and double weak interlayers rock landslide are analyzed.The main research contents and results are as follows:?1?The classification,softening process,shear failure process,and strength variation characteristics of weak interlayer and classification,failure mode of bedding rock landslide are summarized and elaborated.?2?Based on the summary of the bedding rock landslide project in the Lvliang Mountain of Shanxi Province,it is found that the development characteristics of the bedding rock landslide in this area are:often found in the Carboniferous-Permian strata of the gentle dip monoclinic structure;the instability mode is often tensile failure caused by compressive stress,which is induced by slip;the weak interlayer is mudstone or coal seam;the softening factor is heavy rainfall or groundwater;the front edge of the landslides are of fixed slope or steep slope due to human excavation or river side erosion and it is often multi-stage multi-layer sliding.?3?Aiming at the development characteristics of the transitional lithologic landslides in the Lvliangshan to Jinzhong basin,considering the strength attenuation of weak interlayers in different development stages of landslides,a mechanical analysis model of slip-compression-tension fracturing mode with double weak interlayers is established based on the limit equilibrium method.The sliding mode and sliding process of landslide under different mechanical conditions are discussed.?4?By using FLAC^3D numerical simulation software,the influence of shear strength index?c,??of the weak interlayer,the overburden strength index?c,?,E?of the weak interlayer and obliquity value of free surface on landslide stability are analyzed.The deformation and failure mechanism of a bedding rock landslide with a single weak interlayer was identified.?5?By using FLAC^3D numerical simulation software,the deformation law and failure mechanism of bedding rock landslide that contains double weak interbeds under different free face obliquity conditions were analyzed.Three patterns were simulated separately,which are slide controlled by upper weak interlayer,slide controlled by lower weak interlayer and slide controlled by both upper and lower weak interlayers.