Numerical Simulation Studies On The Sustentation Structure Of Anti-Sliding Piles

Friction piles which are an effective measure for controlling the landslide have an important position in treating the landslide in all countries of the world. The present statistics show that friction piles are the most extensive method to treat the landslide in engineering structures. The common internal force analysis method usually considers landslide and friction piles respectively. The interacting between the landslide and friction piles is equal to the simple action of force and don't consider the coordination of deformation, stress of the landslide and friction piles. In fact, the soil-arch effect is the main effective manner in the interacting of pile-soil, and the earth-arch effect is relative to whether the support action can be made full use of or not. There are so many influence factors on pile-earth interacting of friction pile. Such as pile-soil interface parameter, thrust size, gliding mass and anchor layer physical mechanics parameter, pile body anchored depth, size, and intensity etc. If the relation between each parameter and pile-earth interacting can be confirmed, the interacting of pile-earth can be used sufficiently to reach the object of optimum design.In the thesis, main contents include:(1) The develop history, the design calculation theory, procedure about friction piles at present are summed up in the thesis.(2) The research present state about the earth-arch effect of friction piles is introduced in the thesis. From three facets that the form of earth-arch, proper spacing interval and earth feature, the thesis research the earth-arch effect.(3) In the thesis, the three-dimensional model is created and the parameter numerical test is studied by using the rock & soil engineering three-dimensional numerical calculation software FLAC~3D. The pile's total depth of earth-arch effect is studied and the establishment of the earth-arch is analyzed too. According to the numerical simulation test which selects the sliding mechanics parameter, size of piles and spacing etc as parameters and the analysis of earth-arch effect's relation with other parameters, the thesis provides some anti-sliding piles' design instructions which consider different conditions, such as thrust, sliding parameter etc. The test results give the following conclusions: the main influence factors are the sustentation effect of anti-sliding piles and the earth-arch effect. The earth-arch effect's behaviorswill be affected by the different sliding depth and thrust. High cohesion sliding body will increases anti-sliding piles' reinforcement. When the cohesion exceeds 20kPa, the increased extent will decline. Large angle of internal friction sliding body also increases anti-sliding piles' reinforcement. When the angle exceeds 30° , the increased extent will decline. The increase of pile spacing will increase the largest displacement and the relative displacement between the pile and earth, arise excess soil that between piles being extruded and make the anti-sliding piles invalid when the extent exceeds the requirement. When the pile size is 1 X 1.5m, under the condition of test parameters, the critical pile spacing is larger than 6m. When the pile size is 2 X 3m, the critical pile spacing is larger than 8m.