| Surrounding rock stability of underground cavern has always been an important research project that directly related to success or failure of underground engineering. TBM construction method applied in deep and long tunnel has great advantages compared with drilling and blasting method. In view of the characteristics of deeply buried long tunnel, the study on surrounding rock stability is done further to discuss a serious problems, such as stress and deformation characteristics of tunnel surrounding rock and lining, and it is of great practical significance.Based on predecessors’research work about surrounding rock stability, rock-breaking mechanism of TBM, surrounding rock mass plastic zone, factors of influencing surrounding rock stability, surrounding rock destruction mode and instability criterion in the TBM construction process for water diversion tunnel are analyzed firstly. Then, the elastic-plastic theory for surrounding rock in underground chamber and the calculation principle of finite difference software FLAC3D are discussed. Next, on the background of TBM section of water diversion tunnel in Yellow River Water Diverting Project No.3Tunnel in the middle district of Shanxi Province, this paper has analyzed the initial stress field in certain project area, and established3-D numerical calculation model of TBM water diversion tunnel with FLAC3D. The construction process in different supporting time is also analyzed by a numerical simulation, and the results obtained correspond to ordinary rules. Finally, the sensitivity analysis for parameters about representative section in water diversion tunnel is carried, the influences of parameter variation on surrounding rock displacement, surrounding rock stress, surrounding rock mass plastic zone are discussed in detail, and the influences on displacement and stress of lining segment are analyzed, the calculating results provide reference for the design analysis of main lines and other similar water diversion projects. |
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