Model test and stress distribution law of unsymmetrical loading tunnel in bedding rock mass

Abstract

The exit section of Duck River Tunnel owns characteristics of bedding geology and unsymmetrical loading terrain. A centrifugal model test concerning the destruction process of Duck River Tunnel is conducted. Test results are concluded as follows: The surrounding rock at the bottom of the right sidewall is the first to be destroyed; the fracture planes in surrounding rock on both left and right side lead to the ground surface; the rupture angles are different from homogenous rock mass. Results of numerical model are consistent with the test results. For doing some comparative study, numerical models of homogeneous and bedding rock mass are respectively established. Conclusions are summarized from numerical analysis as follows: The stress distribution law of bedding surrounding rock is basically similar with that of homogeneous surrounding rock, while the stress value of bedding surrounding rock is larger than that of homogeneous rock. Meanwhile, the surrounding rock stress of the structural plane increases or decreases by leaps and bounds, and the stress intensity at the bottom of right sidewall is the highest as well as the surrounding rock, there is also the most easily destructible, which is the same as the test result. The research results have significant reference value to similar projects.