Abstract: Splitting failure zones always appear in deep surrounding rocks. In response to this phenomenon, the research has introduced REV and considered closure effect of pre-existing fracture. The hyperbolic curve has been applied to simulate the wing crack propagation path, and a splitting failure model has been established based on curve propagation path. From the microscopic point of view, stress intensity factor and maximum tensile strain theories have been applied to deduce the splitting crack propagation evolution equation. A new method to predict splitting failure has been obtained. FISH language has been applied to embed equation into FLAC, thus this new method has been programmed. The new model is well consistent with Lajtai empirical results. Compared with the old model, new model calculated results are more precise. The maximum decrease of relative error is 25.5% by using new model.

Key words: rock fracture mechanics, stress intensity factor, splitting evolution model, wing crack