Numerical modeling techniques for shield tunnel lining structure using the numerical manifold method (NMM)

An advanced and reasonable calculation for lining structure is very import for rapid structural design and safe construction of shield tunnel. This work extends the numerical manifold method (NMM) for simulating shield tunnel lining structure. In the present method, a contact model based on virtual thin layer is developed for simulating the complex mechanical behaviors of segmental joint. The steel bars and bolts are simplified as truss elements, and coupled with the solid manifold element by virtual spring elements. The loads subjected to lining structure are transformed with the principle of load equivalence, and the ground resistance is simulated by introducing line spring elements into the NMM model of lining structure. Since the element edges are not required to conform to neither the physical lines nor the structural lines in the NMM, the deformation and internal forces can be easily calculated using the present models and techniques with a simple structured mesh. This significantly simplifies the pre-processing for establishing a numerical model for lining structure. The results of a lining structure in metro tunnel show the correctness and accuracy of the present models and techniques.