ABSTRACT
Rock mass usually refers to natural geological rock mass within a certain engineering range which undergoes various geological processes and retains permanent deformation and geological structure traces under the long-term effect of ground stress. The structure plays a major role in controlling the mechanics and deformation characteristics of rock mass. A rock mass is often described according to strength, color, structure, degree of weathering, name, structural plane and other geological information. A comprehensive description of the structural plane contains information about occurrence, spacing, continuity, roughness, aperture, filling characteristics and permeability. The rock mass rating classification system, also known as the geo-mechanical classification, was proposed by Professor Z. T. Bieniawski in South Africa. This system is mainly designed for tunnels, mining and foundation construction. The method for determining joint compressive strength depends on the weathering degree of the structural plane.
