Numerical Analysis Of TBM Construction Process For Long Distance Water Conveyance Tunnel

Based on the existing design theory of shield lining, considering the characteristics of deep TBM tunnel construction, conducted numerical comparison on common model of segment design by finite element analysis software ANSYS, determined the rock pressure distribution pattern of deep tunnel by three-dimensional elastic-plastic finite element simulation analysis of tunnel excavation process. Then carried out excavating process simulation of TBM based on this rock pressure distribution pattern to analyze rock deflection, the rock stress variation concept and the lining stress situation. The analysis concluded as follows:(1)This article aim at the complex of the program processing of the conventional method that applying"anti-acting force"to simulate relaxation when excavated,applying the avianized element theory to predict the relationship between relaxazation ratio and Young's modulus of adjacent rock on the base of original material parameter relationship. Determining the curvilinear relationship between relaxazation ratio and avianized ratio of Young's modulus, get some piece of senseful conclusion, providing fundamental basis for simplifying finite element model.(2)this article based on the main similarities and differences of long-range deep shield tunnel and shallow water tunnel, and analyzed current design model of shallow shield seriously, combined with structural characters and work requirement of long-range deep tunnel, conducted theoretical compare and numerical analysis on homogeneous ring method, more dumplings ring method and beam-spring model. Analysis results shows that beam-spring model reflect segment lining more realistic in the force and work situation, also embodies the characteristic of soft lining, Homogeneous ring method is a simple method with a conservative results, so, It is a simple method for calculation of segment lining and reasonable for simulation.(3)calculating the deformation of surrounding rock before and after excavation process by TBM tunnel simulation process. Reached rock deformation pressure load pattern on deep shield tunnel lining, which is large in top of cave, small in bottom and small change in the middle of the approximate uniform distribution of spiral linear, there is a big difference with shallow shield.(4)Exerting jacking pressure in the cutting face methods to simulate the movement of excavate surface rock, exerting grouting pressure methods to simulate the tail grouting process, changing the material of grouting layer to simulate the tail grouting process, better simulate the TBM construction process, the results of rock deflection, the rock stress variation concept and the lining stress situation, can provide a reference for practical engineering.