The Influence To The Existed Multi-Story Frame Structure Due To Adjacent Shield Tunneling

Uneven settlement, tilting, crack and even unstable failure of buildings are usually resulted from the soil displacement caused by tunneling-induced stress release and adjustment of the soil, which will lead to significant economic loss and prominent social contradiction. Revealing the influence mechanism on working behaviors of the building and deformation characteristics of the soil due to adjacent dynamic construction of the shield tunnel is important to reasonable shield construction parameters selection and protection of the adjacent building. The influence to the additional deformation and internal force of the multi-story frame structure and the nearby ground settlement due to adjacent shield tunneling is studied by theoretical research, laboratory model test and three dimensional simulations systematically. The contents of the dissertation mainly contain as follows:(1) Based on synergy effects of the shield tunnel, soil and multi-story frame structure with independent foundation, the theoretical research method to predict the ground settlement surround the multi-story frame structure is deduced according to the theory of Winkler elastic subgrade. The theoretical research results are well agreement with the results of the numerical analysis, monitoring and laboratory model test, which show that the theoretical research is feasible and reliable. Besides, the theoretical research method is further applied to analyze and predict the ground settlement surrounding the frame structure under different working parameters of shield tunneling.(2) The natural sand ground settlement distribution feature caused by one-through excavation or dynamic excavation of the shield tunnel based on different ground loss ratio, and the ratio between the stable sand ground settlement trough width and the tunnel depth caused by the complete passing of shield tunnel are both agreement with the existing research results, which shows that the independently developing test device to simulate different ground loss and dynamic construction of a shield tunnel is feasible and reliable.(3) The influence of different sensitive factors such as the lateral spacing and oblique angle between the shield tunnel and frame structure, the foundation form and the tunnel depth to the additional deformation and strain of the frame structure and the nearby sand ground settlement is also studied through the laboratry model test simulating the shield tunnel passing through a lateral multy-story frame structure.(4) The influence of the grouting pressure and support pressure acting on the shield excavated surface to the additional deformation and internal force of the frame structure and the nearby sand ground settlement is studied by the 3D numerical analysis profoundly. According to numerical results, the reasonable valve of the grouting pressure and support pressure acting on the shield excavated surface is recommended during the shield tunnel passing through a lateral multy-story frame structure.(5) The pre-grouting reinforcement technology used in the stratum around foundations of the frame structure is proposed and validated according to the numerical result, which could protect the frame structure from passive reinforcement to active harm reduction.