Deformation and Sensitivity Analysis of Lateral Pile of Foundation Pit under Vertical Load

Abstract

In order to explore the side deformation of the retaining piles of the foundation pit under vertical load and the sensitivity analysis of influencing factors, based on the foundation pit of a subway station of Nanning Metro Line 5, firstly, the presence of vertical load is compared and analyzed through field monitoring data. Then use FLAC3D to establish a numerical model to verify the accuracy of the numerical model by comparing with the monitoring data, and then study the maximum displacement of each factor on the lateral pile based on the numerical model, and carry out sensitivity analysis of influencing factors through grey correlation method. The results show that: the pre-acting vertical load increases the maximum displacement of the lateral pile by 20.2%, and the position of the maximum displacement of the lateral pile is lowered by 3m, which weakens the horizontal bearing capacity of the retaining pile, but has little effect on the deformation of the lateral pile; the vertical load increases When it is 3 times larger, the maximum displacement of the lateral pile is close to the pre-warning value, and the adverse effects of the vertical load should be fully considered. The second steel support diameter can be adjusted first in the design optimization; the cohesive force and internal friction angle of the soil parameters affect the surrounding pile. The side deformation has a greater impact and should be carefully determined based on indoor tests and local engineering experience.