Research On The Horizontal Bearing Characteristics And Calculation Methods Of Flexible Large-diameter And Rock-socketed Pile

Based on the present status of rock-rocketed piles and calculation methods of piles under horizontal loads, the load-bearing characteristic and calculation methods of flexible major diameter piles which bear horizontal load is researched by using theoretical analysis and numerical simulation, combining the model and field tests. The work and the main conclusions are as follows:(1)Combined with the field materials of large-diameter steel pipe piles in a coal harbor, the calculation model of contacted nonlinear FEM which is used to analysis the pile which bear the horizontal load with covering soil is put forward. When the soil is considered, the bearing characteristic of flexible rock-socketed piles is studied in the situation of pile's larger horizontal load with contact nonlinear FEM. Conclusions are made through analyze that the horizontal bearing capacity of large diameter rock-socketed piles is mainly relied to the compression of rock in front of piles, and the load ratio of which is responded by the pile skin friction is very little; the horizontal subsidiary stress concentrates on the between the rock and the soil, and the pile body here is reinforced in the design process; during the construction of large diameter piles, the rock is not destroyed and the contact between the pile and rock must hold good.(2)Considered to the elasto-plastic deformation of the soil, pile-soil contact non-linear FEM and"m"method with linear elastic of pile-soil, the difference of two kinds of calculation methods in case of different large horizontal load applied to the pile block is analysised compared with the calculation results of"m"method. The interaction of pile-soil in the condition of the horizontal load is objectively reflected in access of stiffness parameters with 3-D nonlinear FEM calculation model which considers the pile-soil interaction of face-to-face contact.(3)The interaction between the rock and the pile under the conditions of non-covered soil is analysised and the deformation of the structure which bears the largest horizontal load is verified with nonlinear FEM considered with face-to-face contact. Besides, the influence of bearing capacity and deformation resulted to different embedded depth is considered; the best embedded depth is 5 ~ 6 times of the pile diameter.