Study on the Settlement Affected Zones of Raft Foundation Buildings Induced by Shield Construction

With continuous development of urbanization, the settlement of existing buildings induced by shield construction disturbances has become a core issue of concern for environmental safety assessment. For the transverse settlement, longitudinal settlement and twist deformation of the raft foundation building induced by the whole process of shield construction, FLAC^3D finite difference software is used for in-depth study, and the shield construction disturbance plan affected zone has been divided into negligible affected zone, transition zone and dangerous affected zone. The results show that the average transverse and longitudinal settlement affected zones of buildings are parabolic, the transverse overall tilt affected zone is semi-elliptical, the longitudinal overall tilt affected zone is quasi-parabolic and the twist deformation affected zone is quasi-circular. During the shield construction process, the maximum values of transverse average settlement, transverse overall tilt and longitudinal average settlement of the building occur at the completion of the shield crossing, the overall longitudinal tilt and twist deformation of the building will have reached a maximum by the time the shield reaches the central part of the building, which indicates that the assessment of the safety of existing building settlement in shield crossing construction should pay attention to the process of shield construction. The results of the study can provide a theoretical basis for assessing the environmental safety of shield construction in dense urban areas.