Simulation Of Deep Excavation And Shoring With FEM Based On ANSYS

With the rapid development of city construction, a great number of high-rises are constructed together with the exploitation of the underground structure, which surely brings large-scale excavation and shoring of the foundation pit project. In this paper, the process of Qingdao wanbang square excavation and shoring is simulated by using elastic-plastic finite element which is provided by ANSYS. On the basis of considering soil-structure interaction, a plane FEM model for simulating excavation is established. The soil adopts Drucker-Prager ideal elastic-plastic stress-stain model, soil body use four-nodes parametric quadrilateral element, anchor rod use space link element. The contact pair element is used for describing bond-slip behavior between the pile and soil. In this program, the"element birth and death"method is adopted to simulate the stepping excavation of the foundation pit. The results from the comparison between calculated values and field results show the method of ANSYS analysis is practical.Based on the calculated results of the finite element analysis, some conclusions are obtained as follows: For the project, the maximal displacement is appeared on the bottom of pile. The apophysis of the pit bottom increases with the longer distance from the wall, reaching its maximum value in the middle of the pit. The sedimentation values of earth surface around the pit increases gradually along with the stepping excavation. The equivalent stress value of the soil is minimal at earth surface and the bottom of the pit, the maximum value appeared at the bottom of pile and the corner of the pit in the soil. The extent around the pile and the anchor appeared stress concentration phenomenon. The pre-stress anchor tension increases with the excavation depth and the anchor tension reaches to equilibrium in the end of stepping.