DEM modeling of brittle behavior of rock specimens with two infilled flaws

Abstract

Natural fractures often contain infilling materials, such as sheared-off or broken rock fragments and clay, and rock fractures can also be manually infilled by grout. Particle mechanical method was used to study the mechanical properties and cracking processes of rock specimens containing two infilled flaws under uniaxial compression testing. The uniaxial compressive strengths and Young’s moduli of rock specimen increased when the flaws were infilled, but the Poisson’s ratio did not changed monotonously under effect of grout infilling. Grout could significantly improve the mechanical properties of pre-cracked rock specimens with inclination angles of flaws smaller than 45°. In terms of failure modes, crack initiation, propagation and coalescence patterns in rock specimens changed when the flaws were infilled. There are more cracks appearing in the rock specimens containing infilled flaws, and the infilled grout mainly fails in terms of shear. The width and direction of linkage cracks in the bridge region between two flaws can be affected by the infilled grout. The linkage cracks become not evident when the flaw inclination angle is larger than 75°.