Research On The Influences Of Newly-built Subway Station And Tunnels The Stability Of Adjacent Existing Subway Station

At present,with the constant advancement of Kunming city construction,the urban rail transportation in Kunming will develop from a plane line shape to a three-dimensional mesh network,and new subway stations and subway tunnel sections will be built near the existing stations.How to build a new subway station and the new subway tunnel sections near an existing station and how effects on the stability of an existing station requires further study.Therefore,it is of great realistic and theoretical value to carry out the research on the safety and stability of the existing stations in the construction of the corresponding new subway stations and the close proximity of the tunnels.This paper relies on the example of newly built subway station and underground tunnel project in Lianda Street of Kunming rail transit line 4.In view of the fact that the new subway station of No.4 Line Lianda Street adjacent to the existing No.1 Line Lianda Street Station and the underground tunnel passing through the existing No.1Line Lianjie Station at close range,the following research is mainly carried out:(1)The related theories of the influence of the construction of the newly-built station structure on the stability of the existing station structure have been discussed;(2)The new subway station and the under-dig Through the tunnel engineering survey data and field measurement data,the feasibility of the design scheme for the foundation pit support of the new subway station at the No.4 Line Lianda Street of Kunming Rail Transit was checked by using the deep foundation pit software of Lizheng;(3)Basing on the modified Mohr-Coulomb yield Criterion,using Midas/GTS finite element software to build a three-dimensional finite element model,simulating the entire construction process of the construction of the new subway station next to the existing station and the construction of the tunnel underneath the existing station,and studied the construction of the new subway station.And the stress and deformation of the existing station structure under the comprehensive influence of the construction of an undercutting double-line tunnel;(4)Based on the viscoelastic boundary theory and the linear time Based on the integration method,a three-dimensional finite element dynamic analysis model for the integrated transfer station(including the new Line 4 station and the existing Line 1 station)was established,and the displacement,acceleration,stress of the comprehensive transfer station after the completion of the earthquake were studied.The results of the dissertation show that:(1)The maximum settlement value of the ground surface around the foundation pit caused by excavation of the newly constructed subway station is 10.8mm,and the maximum settlement is 0.56 times the depth of the foundation pit from the edge of the foundation pit.(2)The maximum horizontal lateral displacement value of the underground continuous wall in the east side of the newly constructed subway station is 16.40 mm,and the maximum horizontal lateral displacement of the underground continuous wall in the north side of the new subway station is 15.65 mm,1-1 and 2-The numerical simulation results of the maximum horizontal lateral displacement of the diaphragm wall at the 2 section are in good agreement with the actual field measurements.(3)The maximum settlement of the existing station structure caused by the construction of the new subway station and the excavation of the tunnel is 5.31mm;during the construction process of the undercover double-track tunnel passing through the existing station,there is a station structure above the vault of the tunnel.The settlement is mainly affected by the construction of the tunnel.(4)Under the effects of the three types of seismic waves(X-direction),the relatively large values of the X-direction relative displacement of the integrated transfer station structure appear at the two ends of the existing station structure,while the relative displacement of the middle part of the existing station is small;(Y direction)Under the respective effects,the Y-direction relative displacement of the comprehensive transfer station structure is larger at the top of the new station structure,and the existing station structure is smaller.(5)Under the effects of the three types of seismic waves(X-direction),the X-axis maximum response acceleration of the integrated transfer station structure occurs at both ends of the existing subway station,and the X-axis maximum response acceleration is 0.237g(El Centro wave),0.242 respectively.g(San Fernando wave)and 0.230 g(artificial wave);under the effects of the three types of seismic waves(Y direction),the maximum Y-axis response acceleration in the integrated transfer station appears in the middle of the newly constructed station,and the maximum horizontal acceleration in the Y direction is 0.265 g(El Centro wave),0.263 g(San Fernando wave),0.246 g(artificial wave).(6)Under the effects of the three types of seismic waves(X direction),the stress response distribution of the comprehensive transfer station structure is similar.The maximum stress is 26.14Mpa(El Centro wave),28.78Mpa(San Fernando wave),24.87 Mpa,respectively.The major stress responses are mainly concentrated on the connection between the new station andthe terminal well,the connection between the new station and the existing station,the connection between the tunnel passing through the new station,and the junction between the tunnel and the terminal.Under the effects of the three types of seismic waves(Y direction),the stress response distribution of the comprehensive transfer station structure is similar.The maximum stress is 28.66Mpa(El Centro wave),31.84Mpa(San Fernando wave),and 29.38Mpa(artificial wave),respectively.The location of the larger stress response is much more than that of the X-direction earthquake.The main innovations of the paper are:(1)Based on the modified Mohr-Coulomb yield criterion considering the soil unloading effect,based on the soil-structure interaction,the three-dimensional finite element software Midas/GTS is used to carry out the The entire construction process of the new subway station and the subway tunnel section of the station was simulated.The stress and deformation response of the existing station structure under the comprehensive influence of the newly-built subway station and the undercutting tunnel construction were studied.(2)Based on stickiness The elastic boundary theory and the linear time-integration method were used to study the displacement,acceleration,stress response of the integrated transfer station under earthquake and the seismic design of the comprehensive transfer station structure was discussed.