In order to prevent the multi-dynamic disasters induced by rock burst and roof water inrush in strong rock burst coal seams under multi-aquifers, such as is the case with the 207 working face in the Tingnan coal mine considered in this study, the exhibited characteristics of two types of dynamic disasters, namely rock burst and water inrush, were analyzed. Based on the lithology and predicted caving height of the roof, the contradiction between rock burst and water inrush was analyzed. In light of these analyses, an integrated method, roof pre-splitting at a high position and shattering at a low position, was proposed. According to the results of numerical modelling, pre-crack blasting at higher rock layers enables a cantilever roof cave in time, thereby reducing the risk of rock burst, and pre-crack blasting at underlying rock layers helps increase the crushing degree of the rock, which is beneficial for decreasing the caving height of rock layers above goaf, thereby preventing the occurrence of water inrush. Finally, the proposed method was applied in an engineering case, and the effectiveness of this method for prevention and control of multi-dynamics disasters was evaluated by field observations of the caving height of rock layers and micro-seismic monitoring. As a result, the proposed method works well integrally to prevent and control rock burst and water inrush.

To investigate the evolution of floor rockburst instability tendency and optimize borehole pressure-relief horizons in roadways with retained bottom coal, theoretical analysis and numerical simulation were employed to investigate the effects of bottom coal thickness on composite-floor stability, load-bearing and energy-storage states, and borehole pressure-relief response. Based on the equivalent transformed-section method, a stability analysis model for the bottom coal–floor composite structure was established to reveal the mechanism by which increasing bottom coal thickness reduces structural stability and influences the floor instability tendency. Numerical results show that, with increasing bottom coal thickness, the dominant load-bearing and energy-storage response progressively shifts from the floor strata to the bottom coal–floor composite structure and then to thick bottom coal. An energy–stress index K was introduced to characterize the transition in the load-bearing and energy-storage states of the composite floor. Further analysis of the effect of borehole vertical depth indicates that pressure-relief effectiveness depends on the spatial matching between the weakened zone and the main load-bearing and energy-storage zones, rather than on indiscriminately increasing borehole depth. Under the simulated conditions, the reasonable borehole vertical depth ranges from 3.0 to 4.0 m for a bottom coal thickness of 2 m and from 4.0 to 5.0 m for bottom coal thicknesses of 4, 6, and 8 m. The results provide a theoretical reference for understanding the relative evolution of floor rockburst instability tendency and optimizing borehole pressure-relief horizons in roadways with retained bottom coal.