Construction Scheme Selection Of Shallow-buried Excavated Station Tunnel With Large Cross-section And Study On The Effects On Neighboring Structures

The shallow-buried urban subway station tunnel project generally with large cross-section often locates in complexity surrounding environment. If the accident of settlement occurs, it will cause the surface buildings and underground pipeline damage. Therefore there is much practical significance to study the urban underground construction process, deformation regularity and the construction effects on the surrounding environment.This thesis is on the background of Xisi station in Beijing subway 4th line, with the use of numerical simulation and on-site monitoring. Firstly, the form of support usually used for underground engineering will be classified and the simulation of the action of mechanics will be analyzed. At the same time, numerical experiments will be designed to analyze the reasons of ground subsidence caused by shallow-buried excavation tunnel. Secondly, four different simulation schemes of the construction for Xisi station are proposed. The surface subsidence, Arch-top subsidence, tunnel deformation, differential settlement of buildings and so on will be analyzed though comparing. On this basis, the regularity of deformation will be analyzed. Finally, though the simulation of designed construction scheme and comparing with the actual monitoring results, underground pipeline and adjacent surface building safety conditions can be analyzed. Though discussing the reasons of the difference between numerical simulation and the actual monitoring results, numerical simulation can be understood accurately. The main results are as follows:1. Though summarizing the form and mechanical effects of support usually used for underground engineering, the common simulation methods of support will be summarized.2. Though numerical simulation of the reasons of ground subsidence caused by shallow-buried excavation tunnel. The main factors and secondary factors can be received, and then the control measures can be summarized.3. Though numerical simulation of four construction schemes for Xisi subway station, the best suitable scheme for the construction of Xisi subway station, and the best scheme for the protection of existing structures can be chosen.4. The deformation regularity between the excavation of shallow-buried subway station tunnel with large cross-section and the deformation can be received. An important reference provides to the similar projects to forecast the development trend of the deformation.5. Contrast the forecast result with the deformation criteria, the safety of pipeline and neighboring buildings can be evaluated.