Abstract: In response to the splitting failure of fractured rock mass under coupling effect of seepage- stress, the theory of fluid-solid coupling is firstly used to calculate the element stress. Then based on the rule of initiation, extension, coalescence of microcracks, the hyperbolic curve is applied to simulate the wing crack propagation path. In view of the effect of mode II stress intensity near microcrack tip on propagation path, a splitting failure model is established based on a curve propagation path under the coupling effect of seepage-stress. Fish language is utilized to program the new method through the secondary development of FLAC3D. Compared with Lajtai empirical formula, the results of new model are consistent with Lajtai empirical results.

Key words: fluid-solid coupling, stress intensity factor, splitting evolution model, wing crack