An analytical method for mixed-mode propagation of pressurized fractures in remotely compressed rocks

An analytical method for mixed-mode (mode I and mode II) propagation of pre ssurized fractures in remotely compressed rocks is presented in this paper. Stress intensity factors for such fractured rocks subjected to two-dimensi onal stress system are formulated approximately. A sequential crack tip pro pagation algorithm is developed in conjunction with the maximum tensile str ess criterion for crack extension. For updating stress intensity factors du ring crack tip propagation, a dynamic fictitious fracture plane is used. Ba sed on the displacement correlation technique, which is usually used in bou ndary element/finite element analyses, for computing stress intensity facto rs in terms of nodal displacements, further simplification in the estimatio n of crack opening and sliding displacements is suggested. The proposed met hod is verified comparing results (stress intensity factors, propagation pa ths and crack opening and sliding displacements) with that obtained from a boundary element based program and available in literatures. Results are fo und in good agreements for all the verification examples, while the propose d method requires a trivial computing time.