Analysis Of Vertical And Lateral Bearing Capacity Of Single Pile Base On The Micro-mechanism

The bearing capacity and failure mode of pile foundation was a hot research in geotechnical engineering field in past years.From the perspective of analyzing the interaction of pile and soil,it was very important to studied the development of pile end resistance with settlement.Many researchers have used a model test method,combined with some finite element numerical simulation software,to systematically studied the single pile penetration process in sand.For the case of large displacement and deformation of soil during pile settlement,numerical simulation analysis by discrete element software could overcomed the limitations of traditional continuum theory and better simulated the settlement process of pile in sandy soil foundation.In fact,the numerical simulation of pile penetration process in sand foundations has been carried out by two-dimensional particle flow method,which was very different from the actual three-dimensional situation.Also,there was no research on the influence of the soil density of the on the bearing capacity and failure mode of the pile foundation.From the microscopic point of view,the discrete element software PFC3 D is used to simulate the settlement process of pile in different density sand foundations.The different ground was generated using the multi-layer under-compaction method,the vertical loaded pile was generated by the rigid wall and the velocity was applied to simulate the vertical loading process.The horizontal loaded pile was formed by particles,and the horizontal force was applied to the top particle to simulate the horizontal loading process.The following conclusions are obtained:1.By analyzing the curve variation of the bearing capacity of the vertical pile end with the displacement,it is conclude that the greater the buried depth of the pile body,the greater the bearing capacity of the pile end.2.The failure model of pile foundation is analyzed by the change of soil void ratio,the local deformation field of the ground particles,the velocity field and stress state under shallow and deep burial conditions,and compared with previous theories and experiments,and comparing the simulated bearing capacity results with the theoretical solutions of the ultimate bearing capacity,the applicability and rationality of the ultimate bearing capacity formula of foundation under different failure modes are obtained.It is feasible to use the discrete element software PFC3 D to simulate the pile settlement process in the sandfoundation.3.For the vertical pile with or without friction,the normal force on the pile side is counted,the force chain distribution on the pile side and the stress path of the monitoring point are analyzed,and the interaction between the pile end and the pile side is studied.It is conclude that the greater the density of the soil,the stronger the strengthening effect of the pile end on the pile side,and the more significant the strengthening effect of the pile end on the pile side.4.By applying horizontal load to rigid pile top,the velocity field and stress path of ground particles are analyzed.Compared with the previous model tests,the numerical simulation results are proved to be reasonable.