Study On Influence Of Shield Tunnel Construction On Pile Foundation-frame Structure

With the rapid development of underground transportation, Shield has been adopted widely in the process of tunnel construction. However, due to the planning of the whole metro line, it is inevitable for the shielding tunnel to pass through buildings with piling foundation frame-structure, which may affect the safety of the subway, thus it is significant to conduct some research in this field. Meanwhile, there are few previous studies on the influence of shielding construction. Therefore; it is of great necessity to conduct a thorough study about the effect of shield. With this focus, this paper endeavors to do the following work:Firstly, this study describes the research background and significance. Furthermore, it summarizes the previous studies about the impact of shielding on the pile and the surrounding, and it proposes the research questions to be addressed in this thesis.Secondly, this paper analyzes the principles and patterns of shielding excavation on the surrounding soil and the methods to predict soil deformation, and the present study discusses mutual influence between shield construction and piling foundation frame-structure and their factors. Then it sums up the patterns of building deformation and proposes measures to control and deal with the problem that the shields pass through under buildings.Thirdly, with numerical simulation method, this paper studies how the shield construction influences the force and deformation of the pile and frame structure, and it also assesses the safety of buildings. It finds that such factors as the soil parameter, the distance between the tunnel structure and the frame, the construction stiffness affect the deformation of frame and the earth surface, and the pressure of driving face just has little impact. Finally, through theoretical analysis and numerical simulation method, this research obtains the slot peck formula to predict the frame and the Peck formula about the revised stiffness to predict the building subsidence.Fourthly, this paper researches the influence of paralleling holes tunnel shield on the pile deformation and internal forces, and it divides the piles into A, B, C three zones. This study analyzes how different shield construction schemes with two holes affect the superstructure. It finds that the worst scheme is that the construction begins with the right, then the left, and it puts much emphasis on the analysis of the consequence of the worst construction scheme. This study puts forward the revised peck formula of the earth subsidence caused by parallel construction with two holes and the Peck formula to predict the subsidence of buildings.At last, this research takes B106 house building construction as an specific example, which is on the Guangzhou Metro Line 6, Haizhu Square—Beijing Road. Using numerical simulation method, the present study analyzes the impact of two holes tunnel excavation on the post underpinning structure and the assessment of building safety. The result shows that in the process of shield, the influence on the frame structure of building B106 is relatively small, and it does not affect their normal use. The numerical simulation results and the regularity of data monitored in the field are consistent, which proves the feasibility of numerical simulation.