The Research On Southwest Mountainous Rock Slope Of Wedge Structure Instability Mechanism And Motion Characteristics

The Southwest China,because of its special geological environmental conditions,leading to avalanches, mudslides, landslides and other geological disasters take placefrequently in this aera. Large landslide with large-scale, complex mechanism, seriousjeopardize, difficult prevention and treatment and poses a serious threat to the lives ofthe people and the country’s economic construction. It take the Yankou landslide ofYinjiang county in Guizhou Province as an example to made an in-depth study on themountains of southwest rock slope instability and movement of the wedge-shapedstructure.Yankou Landslide is located in Yankou reach of the Yinjiang river left bank,4.1kilometers from the Yinjiang River County in Guizhou Province，in1996September18,23,the slopes of the landslide from the elevation of670m printed on the left bankof the rivers into the fast elevation for the valley of474m square is about260×104m3,Form a51.4m high natural rockfill dam and a lake, blocking Yinjiang river and Yin(jiang)-Song (tao) road, resulting in a difficultestimate of the loss. Therefore, Toresearch the wedge rocky landslide have a great significance. This article first instanceYankou landslide investigations conducted, Then analyz the engineering geologicalenvironment of the study area, Described the characteristics of the study arealandslide slope geometry and boundary characteristics on the basis of it, Proposedseveral landslides sliding wedge failure mode，Combination of three numericalsimulation instability and failure mechanism of the cause of the landslide, and duringexercise, analysis the before and after excavation slope stability and evaluation of thelimit equilibrium method, Finally, Put forward the wedge sliding mode. Specificresearch and findings are as follows:1.Yankou slopes in the mouth on the grounds of a gradient slope of sedimentarydisasters, the regional geological structure development, water development conditions,land-use type situation, lithology and rock structure type, seismic, rainfall and reservoir rock layers, the overall occurrence of N20E/SE/26-30slope and Soft doublestructural features. Medium-Thick layer of limestone in the upper Yulong Mountainsof section with high strength, hard texture. Lower soft layer of sand Fort Bay,, marl,clay shale, Lower intensity, water can easily soften.2.Through uniaxial compression and triaxial compression test to get T1y2limestone and T1y1clay shale, mudstone physical and mechanical parameters.3. Proposed two kinds of sliding wedge failure modes：Sliding along the bottomsurface of the slide-sided、Sliding along the bottom surface and the side surface of thedouble-sided sliding crack.4.Using three-dimensional finite difference method (FLAC3D) the Yankoulandslide natural conditions before excavation, excavation storm conditions in naturalconditions and after excavation conducted a comparative analysis of stress and strain,simulation results show that:①before excavation slopes in natural conditions withminimal deformation, the slope in a steady state; foot of the slope after excavationstress concentration, the displacement of the slope increases, the slope of the stressfield after self-adjusting, for the time being in a steady state; open dug stormconditions slope stress concentration is more obvious, displacement continues toincrease, eventually leading to landslide.②the slope of the shear strain incrementwith mainly concentrated in T1y1segment shale, marl weak layer, this weakness tobring produce shear stress concentration until the destruction of the sliding slopeconditions.5.Using three-dimensional discrete element analysis method (3DEC) of Yankoulandslide during exercise, simulation results show that: Rock Landslide in alarge-scale high-speed remote rocky landslide, has a slide to start fast, hardacceleration in the process of slidinghigh-speed sliding in the strongly hindereddeceleration stop.6.Using qualitative and quantitative (three-dimensional limit equilibrium analysis)on the natural slope after excavation and storm conditions were stable analysis, theformer stability factor of0.96, which is0.83.