<p>Fault-slip causes severe damage in underground engineering activities. It is physically and numerically challenging to investigate due to inaccessibility and difficulty simulating rock failure response under dynamic conditions. Moreover, high water pressure creates additional challenges in deep mining activities. Using a distinct element method, the hydromechanical response of rockmass to fault-slip and its rockburst mechanisms was investigated. The results of the dynamic analyses show that the onset of the seismic radiated energy is associated with instantaneous stress drop around the fault. The magnitude of the peak particle velocity (PPV) at the tunnel wall is higher than the near-fault PPV. The strain energy density (SED) scales with increasing pore pressure. Additionally, hydraulic conditions have a strengthening effect near-fault—as shown by lower particle velocities—and a weakening effect at the tunnel free-face. The findings of this study further improve the understanding of fault-slip burst mechanism under hydrological conditions.</p>