Influence Of Large Scale Deep Foundation Pit Construction On Surrounding Environment In Narrow Space

With the continuous development of urban underground space construction process, the quantity and scale of deep foundation pit engineering has been gradually expanding. In the process of dewatering and construction of foundation pit engineering, the change of groundwater level and the interaction of soil and excavation supporting structure often cause certain influence to foundation pit surrounding environment, including the deep pit resilience, the settlements of soil around foundation pit, the lean and deformation of foundation pit, the settlements and lean of buildings around foundation. In this paper, by building the finite element analysis model, through the numerical analysis combined with field monitoring of large-scale deep foundation pit of shenzhen, the influence of large-scale deep foundation pit construction on surrounding environment in narrow space is analyzed. The main contributions of this thesis are described in the following:(1) A finite element analysis model of soil without foundations piles or structures is setup to simulate the influence of the soil with different soil physical and mechanical index on the deep pit resilience; The same finite element analysis models are setup to simulate the influence of excavation depth, excavation area and foundations piles on deep foundation pit construction. The influencing factors for the bottom upheaval of foundation pits are analyzed, and use the numerical simulation to modify the existing calculation methods.(2) Based on the typical soil conditions of Che Kung Miu in Shenzhen, a three dimensional finite element model considering the dewatering, soil excavation and the interactions between the soil and structures is setup to simulate the deep foundation pit construction. The influence of large-scale deep foundation pit in heterogeneous soil on the settlements of soil around foundation pit, the lean and deformation of foundation pit and the settlements and lean of buildings around foundation is analyzed based on the finite element model.(3) The deformation of deep foundation pit and the influence of surrounding environment are monitored in Che Kung Miu, Shenzhen, including the deep pit resilience, the settlements of soil around foundation pit, the lean and deformation of foundation pit, the settlements of buildings around foundation. With the monitoring data of statistical processing, the numerical analysis results and the field monitoring results are compared with each other, and found that the two are close, which shows that the numerical model analysis can simulate the construction of foundation pit well.3-D settlements of buildings arounding the foundation pit construction caused by excavation are also studied.