Reliability Analysis on Multiple Failure Modes of Underground Chambers Based on the Narrow Boundary Method

Abstract

This paper proposes to study the stability of underground chambers while taking into account the nonlinear characteristics of geotechnical materials and pore water. According to the upper bound theorem of nonlinear limit analysis and the reliability theory, the failure mode and reliability model of underground chambers are established considering the pore water effect. The upper bound solution expression of the surrounding rock pressure in the underground chamber is deduced. The variation law of the surrounding rock pressure is analyzed under different parameters. At the same time, based on the narrow boundary method considering the correlation of multiple failure modes, the influence of different random parameters on the failure probability and reliability index of underground chambers is studied. The results show that the water-level line height, pore water pressure coefficient and Hoek-Brown failure criterion parameter have significant effects on the surrounding rock pressure and underground chamber reliability. In addition, the concept of the safety level is introduced, and the minimum-support force range of the underground chamber with safety level 1 is obtained under different random parameters. The research results can provide a theoretical basis and reference for the structural safety evaluation of underground chambers.