The Structural Design And Optimization Of Anchoring-drawing Anti-slide Pile Of Shuang Yantang Landslide In The Three Gorges Reservoir Region

The Shuang Yantang landslide is an old one which has been local deformation by gets rainfallinfluence. The landslide stability factor will be decreased significantly when the reservoir poollevel increased to175m, or decreased from175m to145m, have the possibility of overallinstability and glide. The result is that the life safety will be great threat of10thousand residentswho located in relocation area of the landslide back. So we must make engineering control.The article has made calculation estimation to the landslide stability and thrust which basedon comprehensive study on the basis characteristics of the landslide boundary range, deformationprocess, geological structure, and geotechnical parameters, and on the effect and formationmechanism of rainfall, waterground, reservoir water level infiltration and so on which affectlandslide stability. The soggy corrosive effect to steel members is indispensable by geotechnicalfracture system bacause the effective supporting and retaining site is located in Three Gorges reservoirreinfiltration zone, sliding mass is mudstone, gravelly soil of sandstone cataclastic, slide bed material ismudstone, silty mudstone, and has significantly demineralization of landslide soil and slide bedrock after reservoir water long period immersion. According to the need of the landslidegeological conditions and building protection in reservoir water immersion area, the papercompare and optimize cantilevered anti-slide pile and Anchoring-drawing anti-slide pile, and putsforward economic and reasonable optimal treatment scheme.(1)The landslide was overall stability before Three Gorges reservoir impoundment. Thelandslide stability decreased significantly because of reservoir water immersion (workingcondition Ⅲ) after the reservoir impoundment. The stability coefficient will be decreased from1.061to1.068and security reserve will be deficiency because of the effect of the reservoir leveldecrease and rainfall (working condition IV).(2)The landslide stability is the lowest, is the most unfavorable working condition and beused as design working condition when the water level decreased from175m to145m. The safetyfactor is1.15, is1500kN/m of landslide thrust where anti slide pile is set up in1-1’ profile，and is 2250kN/m of landslide thrust where anti slide pile is set up in2-2’ profile.(3)In order to ensure building safety after reservoir storage, use anti-slide pile under building,make the comparison and selection between cantilevered anti-slide pile with anchor-pull anti-slidepile. The result is that anchorage pile is the design scheme of anti-slide retaining engineering.(4)According to earthwork quantity calculation of two design schemes, the anchor-pullanti-slide pile can save investment256million yuan, which is the best scheme.