Fracture Splitting Mechanism of Jointed Rock Mass under Compressive-Shear Stress and Grouted Pressure

Abstract

The cracking and propagation regulations of compressive-shear rock cracks and the evolution regulations of the stress intensity factor at the branch crack tip under the grouting pressure were discussed in this article. The fracture failure mechanism of rock bridge in the compressive-shear stress state under the effect of grouting pressure was also studied and a fracture failure criterion was put forward. The fracture failure criterion was applied to a example and some useful conclusions were drawn. The grouted pressure and the lateral stress are the key factors which remarkably effect the stress intensity factor KI at the branch crack tip when the certain axial stress and friction coefficient is known. The larger grouting pressure and the smaller value of the lateral stress result in the larger the initial stress intensity factor KI at the branch crack cusp.Under the certain stress and friction coefficient, the higher grouted pressure and lateral tension stress together is easier to lead to crack transfixation. A new way was offered which studied the fracture transfixation of fractured rock mass in the interaction of grouting pressure field and stress field.