Prediction Of Ground Surface Settlement Of Metro Shield Tunnel Construction And Its Influence On The Adjacent Structure

Inevitably disturbed soil,shield construction caused the movement and deformation of the surrounding soil,and may be harmful to the existing construction.Basing on the shield project of Changchun Metro Line No.1,the mechanism of ground movement and deformation,stratum sedimentation characteristics and deformation influencing factors caused by Shield tunnel construction was discussed,and building subsidence and the deformation of the surface which is caused by of shield tunnel excavation was analyzed in using stochastic medium theory,Peck formula,Grey Model,numerical analysis and field monitoring.The main contents are as follows:?1?The mechanism of shield tunnel construction caused ground settlement was dissected,and according to its evolutionary curve,the general rule of ground surface settlement of shield excavation was summarized,the stress changes and deformation type at different times was analyzed.?2?By using the linear regression analysis method of Peck formula,the normal distribution curve of ground surface settlement was obtained,and the maximum settlement and the width coefficient of the center line of the tunnel were getted.?3?By introducing the stochastic medium theory,cross sectional surface settlement curve was obtained by MATLAB programming.According to the characteristics of Changchun subway tunnel,the formula of random medium was simplified,and the formula of random medium are simplified.The results of surface subsidence by two methods of the simplified formula and programming calculation was compared,and the simplified formula for predicting surface subsidence based onstochastic medium method was obtained.The influence of the depth of the tunnel and the formation of the impact angle on the settlement was analyzed.?4?Based on the Grey Prediction Theory,the adaptive GM?1,1?model was established to predict the ground surface subsidence,and the results were evaluated by the method of post test.?5?Through FLAC^3D software,the circular excavation program was compiled to simulate the shield construction process using the FISH language,and the evolution process of the surface deformation during construction was analyzed.The results of random medium theory,numerical simulation and fitting Peck formula three methods were compared and analyzed.?6?The damage form of buildings was summarized,and the evaluation method of the influence of shield tunnel construction on buildings was analyzed,the influence of different deviation ratio on the slope settlement of buildings was analyzed by numerical simulation.