| Stability evaluation of surrounding rockmass is an important link to safe construction of underground engineering. TBM construction has more technical and economic advantages in deeply-buried tunnel than traditional drilling-blasting method. How to guarantee stability of surrounding rockmass in TBM construction of deeply-buried tunnel becomes one of hot and difficult questions in geotechnical engineering, and it is very important for engineering construction.In this paper, the Yellow River Water Conveyance Project3#Tunnel in Shanxi Province was taken as an engineering example. The elastic-plastic theory for geotechnical engineering has been studied, and the impact factors on surrounding rockmass stability of TBM construction have been studied. With FLAC3D, this paper has established numerical simulation model of water conveyance tunnel on TBM construction; physical and mechanical parameters of rockmass have been selected. Calculating analysis of surrounding rock stability about different depths, excavation diameters, internal friction angles and lateral pressure coefficients has been done. Excavation process has been simulated. Numerical analysis of displacement and stress changes on surrounding rockmass stability has been given. According to different stress relieving rates, this paper has discussed and compared mechanics characteristics on surrounding rockmass and lining segment. Meanwhile, with different excavating distances, deformation and stress regularities of surrounding rockmass stability have been studied. It is of importance during the excavation of the tunnel. Analysis results can provide technical support to construction and design in the main water conveyance tunnel and other similar projects. |
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