Failure Mechanism Research On Shennv Xi Qingshi Landslide In The Three Gorges Reservoir

During the Three Gorges Reservoir, the water level in the145~175m annuallybetween periodic cycle movements, the reservoir water to soak bank soil periodicallyreducing the shear strength of rock and soil reservoir bank, affecting the stability ofthe existing slope, causing Bank Slope instability, and therefore stability of slopefailure mechanism and process of reservoir operation has become an importantresearch topic. Thesis landslide in Three Gorges Reservoir River Shennv xi bluestonebackground, theoretical analysis, test analysis and numerical simulation methods toanalyze the factors affecting the river goddess slope instability, combined with modeltest to reproduce the slope failure process by numerical analog its seepage field,displacement field analysis，get the variation of Slope Stability and the establishmentof the sudden slope failure mechanism, mainly achieved the following results:(1) Site investigation to select Shennv xi Bluestone Creek landslide soils atdifferent elevations, the use of screening test, X diffraction spectroscopy, Shearingtest and other methods to analyze changes in particle size, mineral composition andphysical parameters of the same soil slope soil characteristics at different elevations inthe reservoir water, access to the main control factor affecting slope stability.(2) to Shennv xi Qingshi Creek landslide as the prototype, based on a similartheory, established geological test model to simulate failure mechanism of bank slopein the Three Gorges Reservoir River Shennv xi. Proposed reservoir water levelfluctuation test conditions,and model test, geted the data and pore water pressureslope slope crack the case at different elevations, Analysis of slope failure phenomenathroughout the trial process, and get Pore water pressure changes and groundwaterlevel changes is the slope destruction leading incentives during water levelfluctuation.(3) According to the saturated-unsaturated theory, combined with the test model,using Midas/GTS numerical simulation software to simulate test model slopeseepage field to validate the resulte of the test data; and simulate the Shennv xiQingshi slope.Get the process running the reservoir slope seepage field, displacementand shear stress incremental evolution trend: Level rise phase, pore water pressureslope upward trend, toe first appeared displacement; drawdown phase, pore waterpressure slope downward trend, and closing to the amount of displacement of thesliding surface is gradually increased until through.(4) Application Midas/GTS using stable strength reduction coefficient obtained disaster norms and ground stability factor calculated basic agreement, calculated bynumerical simulation and stability analysis of Shen nv xi Qingshi slope during waterlevel, a slight increase in slope stability first after the decrease.(5) According to geomorphological evolution characteristics, combined with thegeological survey information provided by the deformation data from the Shen nv xiQingshi landslide toe softening stage, driven by the collapse of the upper part of thelower motility phase slope rear crack stage, the overall decline in the destructionprocess of the four stages of analysis. the Shen nv xi Qingshi landslide based structure,145m below the water level is assumed to be part of the strain softening zone,145mto175m section is assumed to be elastic segments; to catastrophe theory, based on theprinciple of energy to build the slope cusp catastrophe damage mechanics modelreveals such unexpected landslide slope secondary damage mechanisms.