Twin-tunnelling-induced Response Of Superstructures Considering The Disturbance Of Shield Tunelling To Ground Stress

With the continuous development and construction of underground space in China,urban underground space has become more and more complex and crowded.Because urban subway construction generally lags behind urban construction,when urban subway projects face the constraints of narrow underground space,shield tunnels are often constructed close to buildings with different foundations.In order to facilitate round-trip transportation,urban subway tunnels are usually arranged in two lines.The response of surrounding buildings caused by tunnel excavation is a problem of interaction between complex environmental media and multiple structures.For buildings with different foundation forms,the interaction mechanism is also different.In view of the above problems,this thesis conducts a research on the building response caused by the construction of twin shield tunnels.The specific content is divided into the following parts:Based on the twin tunnels project between Tianjin Metro Line 5 Linhelin Road Station and Jintang Road Station,an open site was selected to monitor tunneling induced ground settlement,and a refined three-dimensional finite element numerical model was established.The measured data and the numerical model calculation results are verified.The well fitting results verify the reliability of the numerical model.Further more,the stress disturbance of surrounding soil and soil deformation caused by shield tunnel construction are studied.The development mechanism of soil arch effect in different stages of shield tunnel construction is revealed.The correlation between stress disturbance patterns and soil displacement patterns during shield tunnel construction is identified.Based on the verified shield construction simulation method,this paper studies the interaction of the twin tunnel in greenfield.The influence of construction of the suceeding tunnel in different stress disturbance areas of the proceding tunnel are analyzed.The influence of different construction sequence of the twin tunnel was studied.The interaction mechanism of twin tunnels construction is revealed through the stress changes and additional soil displacement caused by the first tunnel construction under different construction conditions.For building with different foundations passed by twin tunnels,the response of adjacent raft foundation buildings and pile raft foundation buildings caused by twin tunnels construction is analyzed.Through the comparesion of tunnel constructions in greenfield,adjacent buildings with weight and buildings without weight,the influence of building stiffness and additional stress on soil deformation caused by shield construction is analyzed.The mechanism of the additional settlement of the building caused by the additional stress caused by building is revealed.The loads transfer mechanism of pile-raft foundations during shield construction at different positions is revealed.At the same time,the cumulative settlement and tilt of different foundation buildings caused by the construction of twin tunnels with different layout,different relative positions and different construction sequences are analyzed.This paper discusses the interaction between buildings with different foundation and twin tunnels,and reveals the interaction mechanism between soil,building foundation and tunnels.