Objective Under intense mining in deep parts of coal mines, the roadway support systems are significantly affected by both far- and near-field dynamic loads, accompanied by the strong deformations of the surrounding rocks. Therefore, investigating the failure mechanisms of anchorage bodies under dynamic loading becomes particularly important.

Methods Using the split Hopkinson pressure bar (SHPB) test system and digital image correlation (DIC) technology, the study investigated the mechanical response characteristics of the anchorage bodies under different impact air pressures. Accordingly, it determined dynamic stress-strain relationships, energy dissipation characteristics, cracks’ evolutionary patterns, and failure modes of anchorage bodies.

Results and Conclusions With an increase in impact air pressure, the average peak strength of anchorage bodies increased from approximately 8.3 MPa to 20.8 MPa, and their average secant modulus rose from about 5.5 GPa to 10.4 GPa. Their incident and absorbed energy trended upward, with the absorbed energy proportion rising from 4.39% to 16.86%. In contrast, their reflected energy proportion decreased from 92.71% to 81.82%. Crack distribution in the anchorage bodies transitioned from dispersion to concentration, with strain concentration areas shifting from coal-rock interfaces into coals and the maximum strain increasing significantly. Concurrently, the degree of strain field fluctuations increased quadratically, with the fluctuations in local strain fields intensified. As the impact air pressure increased, the failure morphology of the anchorage bodies evolved from surface crack propagation to the interconnection of deep and more complex cracks, with the failure stages related directly to the non-synergistic deformation among coal-rock masses, anchoring agents, and anchorage bolts. The primary factors causing the failure of anchorage assemblies were identified, including the mismatch effect of wave impedance between coals and rocks, coal brittleness-induced crack propagation, multi-interface synergistic failure, and the mismatch between the parameters of anchoring structures. The results of this study can serve as a reference for stability control of deep roadways.