Mumerical Analysis With FEM On Foundation Pit Excavation And Bolt Supporting

With the development of city construction,more and more underground space is developed.Engineering problems about foundation pit are also emerging out.Dalian is located in the hilly land.The mountainous area is many,and the flat ground is little.Where the geological conditions are complex,the slope instability of foundation pit often occurs.Combining with foundation pit excavation and reinforcement project for Sun Jia Gou training school for Agricultural Bank of China.Dalian branch,using engineering calculation software and the numerical analysis method,the slope instability and bolting problems of the foundation pit excavation were discussed in this paper.This work mainly includes the following several aspects:1.The birth-death element of ANSYS software was used to simulate the excavation process of the foundation pit.The deformations of slope with different depth of excavation were studied.Through the analysis and calculation of results,some curves with the depth of excavation were obtained.These include the deformation curve of slope,the ground-surface settlement curve and the bottom apophysis curve of foundation pit.2.With the aid of the analysis of ANSYS software,considering the effect of seepage on slope stability of foundation pit,the collapse phenomenon of foundation pit during excavation to 3m was simulated.Through the calculation and analysis of the model,the plastic zone map and the displacement map of the slope with different degrees of saturation were obtained.Through the calculation of load conditions,the changes of shear stress and shear strain of the slope with different degrees of saturation were also got.3.The process of bolt support and continuously support after excavation process of instability of slope was simulated using the ANSYS software.Thus,the stress result and strain result of support region were obtained.According to the results of simulation,the anchoring mechanism and the methods for optimization design of bolt were given.4.After the excavation and supporting of the foundation pit,the three-dimensional finite element model of foundation pit was constructed.Then,the stress diagram and strain diagram of the slope were obtained.And the deformation diagram of bolt was also obtained.Finally,the simulation results of the three-dimensional finite element model and the two-dimensional finite element model were compared and analyzed.Through the numerical simulation of the excavation and reinforcement of the fire pool,the results can provide a certain basis for the design of this project and a reference for similar engineering.In this paper,the research has a certain practical value.