| With the continuous development of urban public transport,subway has become an effective way to solve the urban traffic problems.As a new construction method of urban underground tunnel,shield construction has its obvious advantages.However,the construction of underground tunnel inevitably disturbed the formation,resulting in the formation of the settlement deformation,which led to the deformation of pipelines or even destroyed.In this paper,based on the field measured data of Nanjing Metro Xuanwu Gate Station-New model road station shield tunnel,through the construction of shield tunnel construction and calculation parameters inversion determining the simulation process of shield tunnel and using The FLAC3 D software to simulate the formation deformation and pipeline deformation induced by shield tunneling.Finally,the surface settlement and pipeline deformation caused by the construction of double tunnel in Dalian metro line two are predicted.The conclusions are as follows:(1)The lateral deformation of strata induced by shield tunnel construction,with the increase of the depth of the stratum,whose the maximum settlement value increases gradually,and the width of the settlement trough decreases gradually.The earth pressure control of the tunnel face stability and reduces the surface subsidence deformation.With the increase of the earth pressure,lateral surface settlement gradually decreases and the decrease amplitude decreases gradually.With the increase of the grouting pressure,the settlement of the formation decreases gradually,and the effect is obvious.(2)The existence of the underground pipeline can inhibit the deformation of the surrounding strata,and the closer the underground pipeline,the greater the degree of influence.With the increase of the burial depth,the influence degree decreases gradually.(3)The pipeline material and the thickness of the pipeline wall reflect the influence of the pipeline stiffness on the settlement and deformation of the pipeline.The different diameter of the pipeline can be understood as the combination of different pipe stiffness and buried depth.Regardless of whether the pipeline is perpendicular or parallel to the tunnel,the influence of the pipe material,wall thickness,diameter and depth on the stress and deformation of the pipeline is not reasonable.(4)After the right line of Dalian tunnel goes through,the maximum settlement value Dalian subway tunnel shield is 10.0mm.Through the double tunnel,the lateral surface settlement trough does not conform to the superposition theory,the maximum settlement value is 11.26 mm whose shield tunnel formation volume loss rate is 1.46% and the surface settlement trough width coefficient is 0.81.After the right tunnel is connected,the tensile stress of the right tunnel is the largest,the maximum tensile stress is 1.37 MPa,the maximumcompressive stress is in the lateral segment,and the maximum compressive stress is 2.65 MPa.The maximum tensile stress of the tunnel is 1.13 MPa and the maximum compressive stress is2.63 MPa,which is lower than that of the right tunnel.(5)After double lines tunnel of Dalian tunnel go through,The maximum settlement value of gas pipeline is 11.4mm,and sewage pipe's is 9.79 mm.When the right tunnel passes through,gas pipeline's maximum tensile stress is 3.1MPa and the minmum compressive stress is 7.6MPa,and sewage pipeline's maximum tensile stress is 0.95 MPa and the minmum compressive stress is 2.35 MPa.When the left tunnel is connected,gas pipeline's maximum tensile stress is 2.4MPa and the minmum compressive stress is 5.6MPa,and sewage pipeline's maximum tensile stress is 0.80 MPa and the minmum compressive stress is 2.31 MPa and the two pipes are in a safe state. |
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