Numerical study of remote fracturing around a circular opening in rock

Abstract

Remote fracturing exists actually but it is not frequently observed in engineering practice. It attracts much attention on the study of growth process, rupture zone (or location), prerequisites and producing mechanism. A numerical model of a square rock block with a hole in the center was biaxially loaded, according to a constant lateral pressure coefficient, λ. The outer loading is applied in an increment of pressure step by step to simulate continuous and non-decreasing high-stress flow in deep rock. The failure characteristics, occurrence sequence and formation conditions of remote fracturing were discussed based on the numerical simulations using Rock Failure Process Analysis (RFPA2D) code. Research results show that under a lower confinement, remote fracturing might appear in the remote zone which is about 0.5r away from the perimeter of a circular opening, where r is the radius of a circular opening. Remote fracturing can arise repeatedly in en echelon forms when a circular opening is under the same stress boundary condition. Remote fracturing is mainly induced by tensile damage, simultaneously with some shear damage. The location of each sublayer of remote fracturing obeys the modulus ()i r (i = 1, 2, 3, 4), where i denotes the occurrence sequence of remote fracturing. A low lateral pressure is the root cause of the formation of remote fracturing.