Research On The Prediction Of Metro Excavation Deformation Based On The Combination Of Monitoring Information And Numerical Simulation

In this paper,relying on the project "Key Technology Research on Oversized Buried Subway Construction in Prosperous Section" as the research background,structural settlement deformation research was conducted by analyzing the subway construction of People’s Square Station of Changchun City Rail Transit Line 5,combined with the monitoring data of the construction monitoring and measurement system,and using finite element parameter correction and numerical simulation.Through the analysis of the mutual coupling effect of multiple factors subjected to the subway construction process,the construction process simulation and analysis based on the inversion of finite element parameters were used to conduct an in-depth study and analysis of the deformation affected by the subway construction by combining the monitoring data of the subway construction,and the specific research contents include:(1)According to the monitoring data of construction monitoring and measurement system,the measured data are firstly pre-processed and analyzed,and on the basis of data analysis,Gaussian mixture model cluster analysis algorithm is introduced to extract the mean and variance of the maximum horizontal displacement cluster of the enclosure wall.Then,ANSYS finite element model of foundation pit was established,and relying on the stochastic finite element model correction theory,Kriging agent model was introduced,and the finite element model support parameters were used as the object to be corrected and the maximum horizontal displacement of the enclosure wall was used as the correction target,and a method based on the finite element benchmark model parameters correction was constructed to correct the deep foundation pit enclosure wall support parameters.(2)The modified finite element model support parameters were substituted into Midas GTS NX geotechnical finite element software to establish a coupled finite element model between the deep foundation pit,the adjacent existing station,and the high-pressure rotary pile.First,the accuracy of the model was verified by comparing the calculation results of the established model with the actual monitoring data.In view of the coupling effect in the mechanical behavior between the deep foundation pit,the adjacent existing station and the high-pressure rotary pile,the structural parameters and optimization of the high-pressure rotary pile are investigated with the uneven deformation of the soil and the deformation of the adjacent structures as the control parameters.On this basis,considering the uneven deformation of the soil between the deep foundation pit and the high-pressure rotary pile,structural optimization of the bottom of the high-pressure rotary pile is carried out,and then the deformation of the deep foundation pit enclosure wall and the adjacent existing station is analyzed after the high-pressure rotary pile is optimized.(3)Firstly,the overall finite element model under the coupling effect of deep foundation pit-tunnel is established,and the influence of different construction steps of the middle and top slabs of the foundation pit on the surrounding settlement is analyzed,and the deformation law of the enclosure wall structure is dissected.The analysis focuses on the influence of different excavation sequences of the concealed method and the excavation step of adjacent guide holes on the surface settlement,and the optimization of the tunnel excavation process of the concealed method with one buckle arch.A Gaussian function prediction model was introduced and combined with similar projects to establish a prediction model for surface settlement of tunnel construction and to realize the engineering application of the prediction model.