Investigating the dynamic behavior and tensile properties of coal gangue shotcrete under impact loading conditions SHPB device

Shotcrete is the primary support material for coal mine tunnel linings and is often subjected to dynamic loads such as blasting and impact. To promote the resource utilization of coal gangue (CG), this study incorporated it into shotcrete and investigated the dynamic mechanical properties of coal gangue shotcrete (CGSC) at different coal gangue aggregate (CGA) replacement ratios. Impact tensile splitting tests were conducted using a split Hopkinson pressure bar (SHPB) device, and the specimen failure process was recorded with a high-speed camera. The results showed that the dynamic tensile splitting strength (DSTS) and energy absorption of CGSC exhibit a significant strain rate effect, with the strain rate sensitivity of DSTS decreasing as the CGA replacement ratio increases. As the strain rate increases, the elastic limit stress of the specimens rises, and the failure mode tends to become more fragmented. Based on energy theory, this paper establishes a dynamic tensile splitting strength model for CGSC, providing theoretical support for its application in engineering.