Three-dimensional analysis of tunnel face stability in spatially variable soils

摘要

An advanced three-dimensional model is proposed to study the limit state of a tunnel face in spatially variable soils based on the upper bound theorem. The matrix decomposition method for generating the random field is further modified, allowing the soil spatial variability to be accurately captured with less computational effort. Verification exercises are carried out to demonstrate the satisfactory behaviour yielded by the proposed model in comparison with the random numerical method when tunnels are constructed in homogeneous and layered heterogeneous soils. Sensitivity studies are further performed via Monte Carlo simulations, illustrating the important effects of the spatial variability of the shear strength.