Abstract: The foundation for the underground space is an integral part of a complicated system consisting of rock mass, underground rock cavern and building structures above the ground. The stability of the underground space foundation should evaluate stability of rock mass underneath the rock cavern as well as the stability of surrounding rock mass. The failure criteria should include the “failure criteria of rock foundation” and the “failure criteria of surrounding rock mass”.  For the failure criteria of rock foundation, it includes two portions: the bearing capacity of rock mass excluding the influence of rock cavern and the settlement of foundation including the impact of rock cavern. The first portion is focused on the strength failure mode for the maximum bearing capacity that the rock mass could carry. The second portion is concentrated to deformation failure mode for the tolerable settlement for buildings above the ground. For the failure criteria of surrounding rock mass are for the examination of the stress and strain at the rock mass. The analytical method, the stereographic projection graphical analysis method and the numerical simulation method can be used in the stability analysis. Among all locations, the stability criteria for the rock mass at the side walls of the cavern are established for four different categories based on the structural characteristics, the stress level of rock mass and the rock joints: Uniform rock cavern; rock carven with similar rock properties; rock cavern in jointed rock mass and rock cavern.

Key words: foundation for the underground space, rock cavern side walls, failure modes, failure criteria