Analysis On Intrusion Mechanism Of Tunnel Support And The Optimized Scheme For Exchanging Tunnel Arch

As the surrounding rocks of the tunnel’s portal are mostly shallow buried, loose and broken,the tunnel portal’s construction will inevitably produce disturbance to surrounding rocks,changing their initial stress state. Improper construction or supporting control method will causesevere deformation of the surrounding rocks, resulting in the primary support’s intruding into thesecondary lining limit. It can even lead to the buckling failure of the support structure and thenlandslide. In many engineering practices, the similar invasion limit problems happen from time totime，which will undoubtedly affect the engineering quality and bring about delays, increasingcosts and a series of safety problems. At present, a lot of valuable experience has been summed upin a lot of classic cases of construction, and many experts and scholars at home and abroad havebeen dedicated to the theory and practice research on the control of surrounding rocks’ severedeformation.Based on the case of shanziding tunnel engineering of the meizhou-dapu highway, this thesisintends to analyze the causes of the primary support’s intruding into structure ambit that occurredin tunnel entrance of the right line. Besides, this thesis also tries to conduct a research onoptimized scheme for exchanging tunnel arch. According to the geological conditions andconstruction plan of shanziding tunnel, the author analyzes the causes of severe deformation ofthe surrounding rocks from the internal and external perspectives by relating to the deformationregularity which is obtained through analysis of the measurement data. Through the research onthe theory of controlling the stability of surrounding rocks’ serious deformation, the author aimsto find out the reasonable excavation methods and the theoretical basis for the supportingmeasures. In this thesis, the author will use the ANSYS numerical simulation software, andconduct the inverse analysis of surrounding rocks’ displacement, and then carry on simulationanalysis of the arch’s exchanging process and compare the schemes. Finally, the author appliesthe numerical simulation results to the tunnel engineering practice, put forward the optimizedscheme, and evaluate the treatment effect of shanziding tunnel’s construction on arch’s exchange.