At present, coal bursts in working faces of steeply inclined coal seams (SICSs) have rarely been investigated, and current research focuses on the influences of roof breaking and instability of overlying structures in goaf on coal bursts; however, the stress state of coal masses in working faces being subjected to coal bursts is rarely researched. To overcome the above defects, a model for analysing stresses on coal masses in horizontal section of SICSs was established based on the coal burst that occurred in LW5521‐20, Yaojie No. 3 Coal Mine, Lanzhou, Gansu Province, China. Moreover, the mechanism underpinning such a coal burst in SICSs was analysed based on the superposition mechanism of dynamic and static loads. The results show that the side abutment pressure near the roof and floor under the horizontal sections of SICSs is asymmetrically distributed in the vertical direction in which the peak of side abutment pressure near the roof is closer to the working face and therefore is taken as the source of static loads for coal bursts in working faces. When the superimposed dynamic load caused by hanging roof breaking and high static load borne in the coal masses is larger than the critical load for coal burst inception, a coal burst will occur. Furthermore, the superimposed dynamic load induced by coal bursts on the support and the initial static load on the supports are larger than their limiting load, which leads to support collapse and eventually causes dynamic failure of the working face. The coal burst in working faces in horizontal sections of SICSs can be prevented by using deep‐hole presplit blasting in a hard roof, destress blasting in coal masses, and support optimisation of working faces, showing a favourable preventative effect.

Roadway rockbursts seriously restrict the safety production of coal mines; however, the interaction between dynamic loads and roadway surrounding rocks has not been fully considered in existing studies. A dynamic failure analysis model of anchoring supporting structures was established to analyze dynamic effects of stress waves. Taking a rockburst in LW402103 of the Hujiahe coal mine as the case, the theoretical model was well applied and verified. The static cumulative resistance Q_s (210.5 kN) which was incurred by deformation of rocks provided the basis (81.93% in the overall real-time resistance Q) of dynamic failures. However, the additional impact resistance Q_d (46.43 kN) brought about by the energy release in the failure process of elastic zones triggered impact failures. As a result, under conditions that the overall real-time resistance Q (256.93 kN) exceeded the ultimate resistance [Q] (250.8 kN), the dynamic failure of supports occurred. The in situ application was implemented by taking pressure-relief measures and parameter optimizations of roadway supports, which achieved an effective prevention of rockbursts.

Aiming at roadway rockbursts induced by near-field dynamic disturbances, this study explored the mechanical response and failure mechanism of anchored roadway surrounding rocks under this condition through the similarity simulation experiment and theoretical modeling analysis. Results show that the greater the disturbance energy is, the stronger mechanical response of surrounding rocks while the faster its attenuation. The starting acceleration amplitude is relatively smaller while the braking acceleration amplitude is larger in the bolt densification area, which has a better self-stabilizing ability. Anchored roadway surrounding rocks exhibit local impact failure characteristics, and the region facing disturbance is most seriously damaged. The bolt-mesh-cable support structure shows the good resistance to low-energy disturbances, while the impact failure is induced with damages inside support structure increasing abruptly under high-energy disturbances. The impact resistance of local surrounding rocks can be improved by bolt densification. Based on the failure criterion, the surrounding rocks only undergo impact failure in the region facing disturbance, while quasi-static failure occurs in remaining regions. The experimental and theoretical research results have been verified through in-situ measurements, which can provide an important reference for the mechanism and prevention of roadway rockburst under near-field dynamic disturbance.

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In practical engineering, coal burst is usually caused by the combination of high geo-stress and dynamic loading. To study the dynamic response of coal in geo-stress conditions, numerical models of a coupled static–dynamic split Hopkinson pressure bar (SHPB) test system were established, based on which impact tests for coal specimens at different impact speeds and static pre-stress levels were conducted. The mechanical properties, energy characteristics and failure patterns of coal specimens under coupled static and dynamic loads were analyzed. The results show that when the pre-stress is constant, peak stress, the maximum strain energy and the maximum kinetic energy increase significantly with impact speed. Nevertheless, they are less affected by the static pre-stress, increasing linearly with a pre-stress level under lower impact speeds but becoming stable under higher impact speeds. In addition, weak dynamic loads may trigger the instability of the coal specimen in a high pre-stress condition. Overall, both the impact speed and static pre-stress have influence on the mechanical behavior and energy characteristics of coal specimens under coupled static and dynamic loads, but the influence of the impact speed outweighs that of the static pre-stress.