Investigation of floor blasting for rock burst prevention in high-stress roadway under dynamic loading.

Floor blasting has been demonstrated to reduce roadway floor heaving by interrupting the transmission of floor stress, thereby preventing floor rock burst. This study establishes a roadway floor blasting similarity model test system, which incorporates a swing impact testing facility, a high-speed digital image correlation apparatus, and an ultra-dynamic data acquisition instrument. The initial comparison was made between the effects of floor pressure relief measures on roadway dynamic load response characteristics under high-stress section dynamic load conditions. Furthermore, numerical analyses using the RHT constitutive model within LS-DYNA thoroughly investigated the influence of in-situ stress levels, the intensity of dynamic loads, and their placement. The experimental and numerical findings suggest that floor blasting significantly reduces the peak acceleration and stress amplitude of roadway rock mass under dynamic load conditions. Roadway that employ floor blasting for pressure relief have been shown to maintain an intact floor after strong dynamic loads. Additionally, the horizontal-to-vertical stress ratio exerts a predominant influence on crack propagation patterns, and a lateral pressure coefficient that exceeds 1.6 exacerbates asymmetric damage. The influence of dynamic load intensity and application location on damage asymmetry is significant, with the wavefront side exhibiting higher crack complexity.