Analysis of progressive rupture process in surrounding rock for a deep homogeneous and circular opening

Abstract

ABSTRACT The failure mode and scope of rock surrounding a rupture zone have important theoretical value for stability analysis and support design of excavated openings. This study uses the Mohr–Coulomb yield criteria to study the general pattern of rupture progress in rock surrounding circular openings by resolving the analytical solution of stress in elasto-plastic mechanics of the circular openings. The results indicate a dynamic rupture process that develops gradually in homogeneous and circular surrounding rock in the mode of circular annuli under conditions of hydrostatic pressure. The concept of a sub-rupture zone in the surrounding rock is also proposed, and the criterion for rupture of the sub-rupture zone is derived. The calculation of radial stress is undertaken for the outer boundary of the sub-rupture zone, and the calculation method of radii in the sub-rupture zone is obtained. The equality of radii of adjacent sub-rupture zones is taken as the criterion of cessation of rupturing in a rupture zone, and is the criterion upon which the analytical solutions of maximum radius and maximum radial stress are deduced based. The analytical solutions are highly consistent with the engineering example and numerical simulation results using FLAC3D™, which reveals the failure mechanism of surrounding rock and validates the accuracy of the theoretical calculations. The results provide a theoretical basis for optimizing support design and safety assessment in underground engineering projects.