| Sanma Mountain site main city of Fengjie county in Three Gorges ReservoirArea in chongqing city.At present, The construction of the city has beenbasically completed,But according to the cause of formation mechanism and spaceconfiguration of Sanma Mountain landslide, there are still some controversy and thedelay is not yet known.With the normal operation of the three gorges reservoir water storage,the stabilityof Sanma Mountain landslide and subprime landslide has become involved in nationaleconomic development and people’s lives and safety of the urgent need to solve majorenvironmental science issues in this region,Present paper has taken the new site main city of Fengjie County SanmaMountain landslide as study object and has expounded the landslide strcture characte,boundary control conditions and the origin mechanism, which is based on collectingand collating analyzed area geological data, earlier period investigationmaterial. On the basis of a reasonable geological-mechanical model,using Geostudio,the first we research the major conditions of the reservoir water level and thecorresponding landslide stability conditions during the water saturation line for therock mechanics numerical simulation. And then further using three-dimensional fastLagrangian analysis softwore FLAC3D which ITASCA Consulting Group of theUnited States developed research the stress-strain characteristics and deformation ofSanma Mountain landslide. Papers main achievements are as follows:1、Sanma Mountain landslide is a deep slide which is induced by sliding.The leftboundary of Sanma landslide is Sunjia Valley, the right Longzibao Valley, the northside is Lingzhou Road and the south boundary is Yangtze River. The front elevation oflandslide is100m, and the back elevation is310m, the length of north to south is about482~676m, east to west is about745~936m and the whole area is approximately0.56km~2. What’s more, the thickness is between69~171m and the average thicknessis125m. The total square is nearly7500×10~4m~32、The numerical simulation result of Sanma Mountain landslide’s seepage fieldshow that: Reservoir water levels of the Sanma Mountain landslide’s seepage andstability have a greater impact.Under the conditions of equal level,the naturalcondition with little change in rainfall seepage field conditions, rain has little effect onthe seepage field.3、Through the simulation of the stress and deformation of landslide trend,SanmaMountain landslide’s stress and strain concentration zone are mainly distributed in themain slip zone,the secondary slip zone and banks nearby,the edge of the locallandslide occurred weak tensile stress state,the deformation of the secondary landslideis bigger than the main landslide.For example,the water level rises,the maximumdisplacement of the Houzishi landslide is10mm,Over all,the displacement graduallyincreased.After three times high-water level storage test,the landslide tends to beself-stable,through their own adjustment.4、On the base of seepage and stress analysis,using the limit equilibrium analysissoftware Geostudio-SLOPE calculation and analysis, we get some conclusions:(1) During operation of the Three Gorges Reservoir, The whole stabilitycoefficient of Sanma Mountain landslide is1.477in145m water level;when the waterlevel rise,175m water level corresponds to the stability coefficient is1.423.Before therainy season arrival,the water level drop back to145m and the coefficient is1.477.(2) Before the three secondary landslide adopt engineering control,the Houzishilandslide as an example, the stability coefficient is1.102in145m,when the waterlevel rise to175m,the coefficient drop to0.97.but after engineering control,which is1.131~1.264.The local stability has been significantly improved.(3) In the120mm/d storm condition, the whole stability coefficient is1.416in175m.without rainfall which is1.423.Through analysising the secondary landslidestability.In total, rain has little effect on the stability coefficien.Water level fluctuationis the most important factor to affect the slope stability. |
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