Deformation Prediction Of Junxianping Landslide In Yunyang Country Based On Numerical Simulation

The stability of bedding rock slope in high bank is an important part of theresearch on the reservoir bank of the three gorges project to be built. Existing datashow that the rock bedding slope section, especially of high slope section, collapse,landslide and other signs of slope deformation and failure development, this paperstudies the old county was made of a kind of typical landslide is the development ofbedding rock landslide. So for this kind of bank slope deformation failure mechanismand stability of prediction research has important theoretical and practicalsignificance.Based on the research of the traditional landslide forecasting method, this papersummarizes the found its existing problems, and on this basis was proposed based onnumerical simulation of landslide prediction method. Landslide prediction methodbased on numerical simulation, the breakthrough of the traditional prediction methodsused univariate fitting to the geological prototype reflect one-sided shortcomings,through the evolution tendency of the development of training model of thecontinuation of the prototype and gain the understanding of the deformation andfailure characteristics of landslides slope body, achieve the purpose of prediction. Thispaper using numerical simulation method to YunYangXian old county developingtrend of the landslide prediction: namely, first analysis in reservoir level, rainfall andlandslides rock and soil body under the condition of the coupling of seepage fieldchanges; Then the initial hydraulic conditions on the results of seepage analysis,stability analysis for landslide in the reservoir level, rainfall and the couplingconditions on the stability of change tendency; Finally based on the two-dimensionalfinite element model of stress and strain and the fitting of the geological prototype, themodel itself can reflect the formation of landslide evolution mechanism, and through the training model of the continuation of the evolution tendency of the development ofprototype. Through the research and analysis the following conclusions:1.Due to the difference of slope material properties, the main characteristics ofthe seepage field with the water level change is that the change of the seepage fieldare mainly concentrated in the landslide body, and almost no change in bedrock.2.Regular change over water seepage field, mainly in slope devices for rim.Water level rises, POE devices for edge water level also rose, but has a certain lag, sothe saturated flow field on the front of the slope is concave down, until became moregently after water stability; Water drop, then saturated flow field into a convex upwardslope body, and also have certain hysteresis, gently after water stability.3.By the upward slope of pore water pressure in the body gradually becomesmaller, and in the water level of zero. In the process of lifting water, pore waterpressure for overall performance with the rising of water level change big, to reducethe decreased, but in different place and bedrock landslide and its changes in different.At the leading edge of the area is affected by the fluctuation of water level is larger,the change of pore water pressure is bigger, and backup of the landslide mass changeis small. Rock pore water pressure change in the tiny almost can be ignored, whichrelated to the rock permeability is very small.4.The maximum stability coefficient of landslide in reservoir level175m,minimum stability coefficient appears when water level is145m. Slope stabilityincreases with the rise of water level, water level decrease. And when the water leveldrop to145m and maintain a constant, along with the time step of the superposition ofthe pore water pressure in the body dissipates unceasingly, the slope stability can beincreased. This is due to the slope of void water pressure dissipation in the body, canmake the soil within the effective stress increase, so that the stability is improved;When the water level rose to175m and maintain unchanged, at any time step of thesuperposition of the in vitro from water seeping into the slope, the underground waterlevel rise, the slope increases, the pore water pressure in the body so that the soilwithin the effective stress is reduced, reducing slope stability.5.Rainfall can make the slope overall stability under the condition of less rainfalldecreases, but the influence of rainfall on the stability are mainly concentrated in theprocess of rainfall, and the stability of the steep drop, influence on slope stability ofthe whole change trend. Therefore, for old county landslide in reservoir area waterlevel change is main factors, which influence the stability of the rainfall is mainly inthe process of rainfall makes the stability appear abrupt change, to a certain extent affect the stability of the landslide.6.Through numerical computation shows that in the early reservoir water levelfluctuation is the main factors influencing the slope stability, and the influence to thestability of slope, a larger slope displacement. With slope as a whole tend to be gentle,the water level change has a certain influence on the stability of slope, but the effect isabate, the deformation of slope body increases, will eventually flatten out. To sum up,the Jiuxianping landslide in the future under the effect of water level and rainfall, itsoverall is stable.