Abstract: Using DDARF (discontinuous deformation analysis for rock failure) method, the uniaxial and biaxial compression experiments of double-fractured rock mass are numerically investigated. Influences of fracture angle and lateral stress on behaviour of rock mass are studied and the corresponding stress-strain relationship curves are analyzed. Moreover, crack initiation stress and the peak strength of specimens are obtained. In the biaxial compression experiments of double-fractured rock mass, strength envelopes of 45° fractured specimen under different lateral pressures are obtained. Using DDARF mothod, the axial load-displacement curves and crack propagation for four kinds of specimens with different anchor angles are obtained, which can simulate the anchorage effect on fractured rock. The simulation results and the previous splitting tests under similar conditions agree well with each other. The parameters obtained from biaxial compression experiment are used in a practical engineering example; and the differences of damage state between intact rock mass and fracture rock mass are analyzed after excavation of underground cavern by means of the equivalent mechanical character. At the last, the DDARF method is adopted to analyze the stability of an underground cavern with four groups of random joints; and then crack propagation process of jointed rock mass around the cavern are obtained. Besides, the effect of anchor on fractured rock mass are studied through monitoring the displacements of the key points.

Key words: discontinuous deformation analysis, jointed rock mass, crack propagation, underground construction, anchoring effect