Study On Construction Mechanics Effect Of Four Parallel Rectangular Pipe-Jacking

As a kind of construction technology for tunnel and municipal pipeline, rectangular pipe-jacking has the advantages of high utilization rate of cross section and less impact on ground traffic. And in recent years, it has been widely used in the construction of underground space in congested regions of city, which includes the subway entrances and exits, underground street passages and shopping centers.The pipe-jacking construction process can cause different degree of disturbance to the surrounding soil, and surface upheaval and subsidence finally. The former research was limited in environmental effects and mutual influences caused by the mechanical behavior of rectangular pipe-jacking construction.On the background of the four parallel rectangular pipe-jacking project in Nanhai district of Foshan city, this thesis analyze and summarize the process of pipe jacking and the basic principle of EPB pipe-jacking machine, then, theoretical analysis, numerical simulation and field monitoring are used to study the environment effects and mutual influences caused by pipe jacking. The main contents of this thesis are as follows:1. Summarized the principles and characteristics of rectangular pipe jacking, discussed the environmental mechanics effects caused by pipe jacking.2. Simulating pipe jacking with different construction procedures by FLAC3D, the optimum construction sequence of pipe jacking was finally determined by comprehensively considering the surface settlement, settlement of pipe culvert, structure internal force of pipe-jacking and interaction between pipes.3. Analyzed the influence scope and variation of additional stress of soil caused by pipe jacking through numerical simulation.4. Analyzed the mechanical characteristics of the pipe and culverts in pipe jacking, and the mechanical variation of pipe-jacking caused by opening hole between tube segments.5. Simulated the whole process of pipe jacking, thus analyzed the displacement rule of ground Surface, the culvert and the pipes.6. Analyzed the filed measured displacement data, compared the surface subsidence law of the measured and calculated value, the results show that the laws and values are basically identical.