Abstract：The failure forms of rock materials in axisymmetric compression are studied based on the discontinuous bifurcation theory, and a set of experimental data of marbles are simulated. The results are that the brittle fracture form of rock in uniaxial compression is always the tensile fracture，and that of rock in routine triaxial compression is the shear fracture. The inclination angle of the shear band would decrease in steps with increment of lateral pressure. Furthermore，the localization shear band bifurcation takes place at the point in the strain softening area，and the point would be far from the peak point with the increment of lateral pressure.
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2002, Vol. 21 
