Anisotropic Mechanical-Hydraulic Coupling for Deep Buried Tunnel in Soft Rock with Rich Water

Abstract

Qilianshan tunnel is a key project on Lanzhou-Xinjiang passenger dedicated line, located in Gansu province in the Northwest China. It is subjected to geo-stress in soft rock with rich water. Anisotropic mechanical-hydraulic coupling model was performed to investigate the energy density, effective stress and maximum shear stress, displacements and plastic zone of surrounding rock. Consequently, research results show that estimating pore water pressure distribution is important during construction. Energy, effective stress and the maximum shear stress accumulation zone occur and the peak value is located at 2.1 m from side wall. The displacement of crown is most and reaches to 7 cm which is less than ultimate displacement in teams of Code of Design on Tunnel of Railway. Extracted deformation ahead of working face is significantly affected when the distance is less than 8 m. Transversal plastic zone is mainly located at crown, shoulder and invert. The depth of it is 4 m. Pore water pressure and energy distribution ahead of working face increases firstly, and then it reduces. The peak value is located at 10 m ahead of working face. Not only does the analysis method fit for Qilianshan tunnel, but it can be a reference for similar geological engineering.