Study On The Deformation Law And FLAC3D Simulation Of Deep Foundation Pit In Hefei Railway Station

In order to relieve the problem of land shortage and traffic congestion,many cities begin to build subway,the foundation pit engineering develops in the direction of larger and deeper.Therefore,the study on the theory of deformation laws and monitoring of foundation pit in subway station has great significance.In this paper,it uses the method that combines with the theoretical analysis,on-site monitoring and numerical simulation followed the background of deep foundation pit of Tianzhu road station of Hefei rail transit line 2.First of all,the excavation deformation mechanism of subway station and the monitoring scheme of deep foundation pit in Tianzhu road station are described,and monitoring result about deep horizontal displacement of retaining structure,the ground settlement and the axial force of steel support caused by excavation of foundation pit are also analyzed.Then,using FLAC3 D for the construction of deep foundation pit excavation of the whole process of Tianzhu road station is studied by numerical simulation,compared the calculation results under different conditions with the measured data.The main research contents and conclusions are as follows:(1)A systematic summary is made on the deformation mechanism of deep foundation pit,the deformation modes of retaining structure and the influence factors of deep foundation pit deformation.(2)The deformation monitoring scheme for deep foundation pit engineering of Tianzhu Road Station is detailed discussed,including monitoring purposes,monitoring projects and monitoring methods,monitoring frequency and alert value.(3)Through the research and analysis of on-site monitoring data can be found with the increasing of excavation depth,the horizontal displacement of retaining structure increase gradually,and the maximum horizontal displacement moves down gradually,which has the feature of “parabola” shape distribution:small at both ends,big at the middle.Approximately “groove” distribution of surrounding ground settlement outside the pit.The axial force of steel support fluctuates,and it remained basically stable as a whole.(4)By the use of the FLAC3 D software,a simulation of the entire process of excavation is accomplished.The numerical simulation results are basically the same as the overall change law of the measured results,which can verify the scientific nature of FLAC3 D software simulation,with its prediction of deep foundation pit deformation has a certain feasibility.