Simulation Analysis Of Stratum Deformation And Research On Multistage Displacement Control In The Whole Process Of Double-line Shield Tunnel Construction

The construction of the subway tunnel by the shield method has the advantages of safe construction and rapid impact on the surrounding environment,already become a main construction method for the construction of the subway.However,when the shield method is applied,it will still cause deformation of the surrounding stratum and structure.In severe cases,it will affect the safety of life and property of personnel in the surrounding area.An effective measure to control the deformation of the tunnel is to use deep hole grouting around the tunnel to reinforce the stratum.Reasonable selection of grouting parameters is an important factor to ensure good grouting effect of the shield tunnel.This article analyzes the above contents and obtains the following research results:1.The calculation method of ground deformation caused by double line shield construction in homogeneous ground is modified.Based on Mindlin’s basic solution,the total deformation of homogeneous soil under the complex actions of shield machine’s positive thrust,friction between shield shell and soil,synchronous grouting pressure,secondary grouting pressure,soil loss,etc.in the process of shield driving is calculated,and the influence of each factor on the deformation of soil in the process of construction is studied.The theoretical analysis method and the finite element numerical simulation method are compared and analyzed with the example calculation.2.The whole construction process of Kunming Metro Line 5 is simulated.According to the construction conditions of the shield tunnel running under the Cailian river for a long distance in the weak stratum,the numerical simulation analysis of the whole process of shield tunnel construction is carried out based on the key processes such as the excavation of the working face,the assembly of the shield tail lining ring and the grouting filling of the shield tail gap during the construction process.A three-dimensional finite element model of shield construction was established,and the numerical simulation methods of material properties,calculated loads and construction steps were expounded.3.The whole process of shield tunnel deformation and grouting reinforcement scheme are optimized.Firstly,the law of surface settlement and stress deformation of the tube without grouting reinforcement measures is analyzed.Secondly,the parameters of grouting reinforcement,surface stress,surface stress and floating are studied by changing the parameters of grouting reinforcement and grouting pressure.Through the comparative analysis,the safe and reliable and economical grouting reinforcement optimization scheme is obtained.Finally,the geological parameters are changed,and the influence of the formation elastic modulus on the grouting reinforcement effect is analyzed,which has important theoretical significance for the actual construction and Practical value.4.The principle of multistage displacement control is applied to tunnel construction deformation analysis and tunnel deformation control.Based on the principle of numerical simulation and multistage displacement distribution control,the multistage control standard statistical table of each measuring point of surface settlement and vault settlement is established,which realizes the dynamic control of the construction process.Combine the actual monitoring data with the multistage control standard for feedback analysis;compare the measured data with the simulated data to verify the reliability of the numerical simulation data.