Water and mud inrush is a common hazard that threatens workers’ safety and results in huge financial losses during the construction of underground engineering. Failure of water-resisting rock has been recognized as the main reason for the above hazard. Moreover, the coupled effect of seismicity, hydraulic pressure and geostress, deriving from tunnel intersecting with active fault, makes the rock extremely vulnerable to fracturing. Rupture behavior of water-resisting rock is important yet currently underemphasized. This study attempts to transcend aforementioned limitation via a coupled hydro-mechanical discrete element method model. Seismic loading level had a profound influence on the crack initiation–propagation–coalescence. Rock ruptures much more rapidly due to seismic peak ground acceleration of 0.8 g, but remained unbroken under the seismic intensity of IX. No fractures were induced by the seismic intensity smaller than VIII. Crack orientations are slightly dependent on seismic intensity, and fractal feature is enhanced by higher seismic loading level. Fracture propagation is more likely to be caused by low-frequency seismic wave, which also leads to most cracks striking along low inclinations. Macrofailure planes were not formed by the seismic frequency larger than 7 Hz. The highest fractal dimension is observed for the fractures induced at a seismic frequency of 3 Hz. Rupture of water-resisting rock is enhanced by the 30° inclined seismic wave while restrained by the seismic inclination of 60° or 90°. Orientations of macrofailure planes remain constant when the inclination of seismic waves increases from 0° through 30° to 60°; and changes sharply under the vertical seismicity. Both the main strike and fractal feature of cracks were profoundly affected by the angle of seismic wave propagation. The most remarkable fractal feature is observed from the scenario of 30° inclined seismicity. The change of crack length exhibited step profiles when the seismic loading time was longer than one vibration period.
Kong et al. (Thu,) studied this question.