Research On Monitoring And Numerical Simulation Of Subway Foundation Pit

With the rapid development of urban subway projects in China,excavation of urban subway foundation pits is particularly important as the primary project for the construction of subway stations.The research on deformation and excavation displacement control of foundation pits is particularly urgent.This article takes the foundation pit project of a subway station in Beijing as the background.First,it starts with the theoretical analysis of the deformation of the foundation pit,combined with the on-site monitoring during the construction,and uses numerical simulation and monitoring results to compare the stress on the excavation of the subway station Research on distribution and displacement changes;The deformation law of the excavation of the foundation pit under several different working conditions is analyzed;the monitoring data of the internal support shaft force and the ground settlement are obtained,and the on-site monitoring data law curve is drawn and the curve law is analyzed;meanwhile,the excavation process is analyzed The displacement and stress changes of the protective structure,to grasp the results and better guide the construction.The research content and conclusions are as follows:1.According to the actual situation of the project,by studying the monitoring data,and then analyzing whether the layout of the monitoring points is reasonable and whether the development of the monitoring plan meets the specifications,etc.,there are 5 items of surrounding environment monitoring and 3 items of enclosure structure monitoring;collate the monitoring data and analyze the subway The engineering envelope,supporting axial force,and the displacement and ground surface,and then verify the applicability of the monitoring program when excavating the foundation pit.2.The three-dimensional model of the foundation pit is established by Midas meshing.The calculation and analysis of the model shows that with the increasing excavation of the foundation pit,the law of stress and displacement is directly reflected from the displacement cloud diagram and stress cloud diagram,and the road and surface settlement monitoring Deformation data shows that the positions where the maximum displacement occurs are all biased to the middle position of the foundation pit(9?11m position);in the comparison graph of the regular curve under the excavation 5 working conditions,the maximum value of the horizontal displacement of the envelope structure appears at a position of about 8m,and the peak value of the monitored value is slightly smaller than the simulated peak value.3.Carry out various monitoring according to the site monitoring program of the foundation pit,and compare the monitoring results with the numerical simulation law curve,and find that there is a slight error in the finite element simulation law change curve and the actual monitoring data drawing curve,but the overall is basically consistent,which shows The change curve of numerical simulation law has practical guidance significance to a certain extent in the actual engineering construction.Figure 45 table 9 reference 44...