Study On Security Of Circumvallation During EPB Shield Crossing

This dissertation takes the Xi'an subway Two as the project background, studies on the security of the circumvallation during shied crossing, which includes: Mechanism of the soil settlement on the shield tunnel construction of adjacent structure and control measures; Numerical simulation on the shield tunnel construction of adjacent structure; Preliminary establishment of appraisal principle of the circumvallation during shield crossing. Main conclusions in this dissertation are as follows:(1)This dissertation proves that the value of numerical simulation method is closer to actual measurements by contrasting methods of empirical formula and numerical analysis and concludes that numerical simulation method is reliable as the research method on shield tunnel construction crossing through circumvallation.(2)The three dimensional numerical simulation is adopted to study on different foundation treatment methods, contrasting with ordinary foundation. It is proved necessary that composite foundation treatment method, which is better on reinforcement contrasted with other methods.(3)This dissertation takes the biggest settlement and the local dip value as the preliminary appraisal standard, which provides guidance for the shield tunnel construction crossing through circumvallation safely.