Propagation Mechanism of Water-Bearing Cracks in Deep Rock Mass under Blasting Disturbance

Abstract

Based on the principle of fracture mechanics, this paper studies the mechanical model of water-bearing crack development in deep rock mass under blasting disturbance, and derives the expression of the dynamic and static coupling strength of the rock mass. In the meantime, the crack initiation and propagation of tensile shear and compressive shear cracks were investigated to disclose the effect of blasting disturbance, water pressure, geostress and crack angle on crack propagation, and to obtain the formula of crack propagation length. The formula was implemented in a case study. The results show that, in tensile-shear fracture, the geostress accelerates the crack propagation in the same direction; in compressive-shear fracture, the crack inclination angle of the position most vulnerable to compressive-shear fracture varies with the internal friction angle of the rock mass; the blast disturbance load, in a certain sense, elevates the water pressure in the cracks; the crack propagation length decreases in a near linear pattern with the increase in the distance from the explosion source.