Abstract:
During the construction of an urban subway shield tunnel,the overlying soil will experience stress transfer and displacement transfer. To accurately predict the ground settlement caused by the construction of a shield tunnel,based on the calculation model of ground loss under the influence of the "soil arching effect" in the energy method,research on the prediction method of surface settlement of shield construction is carried out. First,the Loganathan formula is optimized and improved by comprehensively considering the tunnel construction method,the "soil arching effect," and other factors. The rebound deformation of the soil mass under the action of soil arching is calculated by Terzaghi theory,and a prediction model of ground settlement for circular shield tunnel construction considering the soil arching effect is established. Second,based on the elastic Maxwell-Betti work exchange theorem and considering the support function of circular shield tunnel lining,the theoretical analytical formula of formation loss caused by tunnel construction under the energy method theory is derived by constructing two groups of elasticity mechanical model calculation models under different stress conditions. Finally,five typical shield tunnel engineering cases are compared and forecasted. The results show that the forecasting method considering the soil arching effect is more effective and that the forecasting result is closer to the actual monitoring settlement value,which verifies that the method has better adaptability and reliability in shield tunnel engineering.