Abstract: Based on the conceptions of the microcrack controlling fracture and asymptotic failure, Griffith proposed the theory of the material brittle fracture in 1921. The underground rock masses are generally subjected tocompressive loading, consequently, the cracks in rock masses are forced to be closed and the crack surfaces are subjected to the loading. Maclintock and Wash established a modified Griffith Maximum Tensile Stress Theory in 1924, which only inspected the friction force τ n=νσ x(ν is the fr...