The Ground Reaction Curve at Tunnel Crown Based on The Unified Strength Failure Criterion in Weak Media

In this paper a new analytical solution for calculating the ground reaction curve at tunnel crown around a circular tunnel, considering true triaxial stress state, is developed. The new solution is based on the unified strength failure criterion; thus, it consists of a wide range of solutions based on different failure criteria such as the Mohr-Coulomb failure criterion and Generalized Twin Shear Stress yield. Validating against the two case studies, it was shown that if the radial displacements are not controlled, a loosening zone is produced above the tunnel. Moreover, it was detected that the value of the radius of Excavation Damaged Zone (EDZ) and the pressure due to EDZ weight depend on the effect of intermediate principal stress. Finally, based on the ground reaction curve, two new achievements “Minimum required support pressure” and “critical strain” were presented.

کلیدواژه ها:

Tunnel ، Ground reaction curve ، Excavation Damaged Zone (EDZ) ، Unified strength failure criterion ، Radial displacement