FEM Analysis On Internal Force And Deformation Of Foundation Pit Considering The Reinforced Soil Behind Retaining Pile

At present, in the design of foundation pit support, In order to ensure the safety of foundation pit engineering, we tend to set a certain thickness of cement soil mixing pile behind the retaining pile. But the software of foundation pit support design is not able to calculate the cement soil mixing pile, so in this paper, we will reinforce the soil behind retaining pile by using PLAXIS finite element program, to consider the effect of cement soil mixing pile on internal force and deformation of foundation pit support system.In this paper, we will use an example of inner brace foundation pit support system. Firstly, introduce the calculation principle of inner brace foundation pit support. Secondly, design the scheme of foundation pit supporting system by using two design softwares of foundation pit support, they are FRWS and FSPW. Comparing the difference between the two kinds of design software of foundation pit support. In the end, build the plane strain finite element model by using PLAXIS 2D finite element program, two kinds of finite element model are built,they are soil reinforcement finite element model and soil unreinforcement finite element model. By changing the thickness of reinforcement soil in the finite element model, analyse the variety law of supporting pile displacement, ground surface settlement and axial force of brace. The cement soil mixing pile behind retaining pile can bear part of soil pressure,and reduce the displacement of retaining structure and ground surface settlement, enhance the security of foundation pit support system. Comparing the difference between the measured values and design values,the retaining effect of cement soil mixing pile is verified.This paper does a finite element analysis for reinforced soil behind retaining pile by using PLAXIS program.It was concluded that the variety law of internal force and deformation of inner brace support form when cement soil mixing pile was set after retaining pile.Above-mentioned research findings can provide references for design and construction of deep foundation pits.