Numerical simulation on progressive failure of heterogeneous rock specimens with a pre-existing three-dimensional crack

Pre-existing flaws in rocks have great influences on the initiation, propagation and coalescence of newly generated cracks, causing strength degradation and final failure. Investigation on the progressive failure and micro-fracture distribution in rocks with pre-existing cracks contributes to understanding the progressive failure of rocks; and thus significant for engineering practice. A numerical tool named RFPA^3D was employed to simulate the progressive fracturing of rock specimens containing a pre-existing crack subjected to uniaxial compression. The microcrack initiation, propagation, coalescence and failure process were reproduced. A contrast analysis between the numerical simulation and previous researches was conducted. Some conclusions can be drawn as follows. In general, the failure process obtained from numerical simulation is similar with that from physical experiments. Anti-wing cracks can be found in the test with homogeneous material; and the phenomenon of anti-wing cracks approaching wing cracks is featured. Fin cracks are likely to be observed with rock specimens containing pre-existing elliptical cracks, which are shown as curved surfaces produced by wing cracks and anti-wing cracks in homogeneous rocks. Heterogeneity affects rock strength and failure significantly. Heterogeneous rocks are easy to damage along the section with pre-existing crack. The meso-scale numerical simulation is effective to simulate the failure processes of rocks, which provides a reference for physic tests and theoretical analysises.