Physical simulation of roadway surrounding rock cumulative failure characteristics under dynamic loading and energy-absorbing support solutions

Roadway surrounding rock in deep coal mines is subjected to the combined effects of static loading and dynamic disturbances, which can induce progressive deformation, crack propagation, and catastrophic instability. To investigate the progressive failure characteristics and mechanisms of roadway surrounding rock under different dynamic impact energies, a physical similarity simulation experiment based on the 21170 transportation roadway of Changcun Coal Mine in the Yima mining area, China. A physical model was established using sand, gypsum, calcium carbonate, and mica powder, with a geometric similarity ratio of 1:25. A dynamic impact loading system equipped with a 20 kg pendulum and a 1 m pendulum rod was employed, and pendulum heights of 0.1–1.1 m were used to generate different impact-energy levels. The corresponding simulated impact energy ranged from 2.42 × 10 4 to 1.31 × 10 6 J. The deformation and failure processes of the roadway surrounding rock were systematically monitored using displacement measurements, an 8-channel acoustic emission monitoring system, pressure sensors, and high-speed imaging. The results show that roadway deformation increases progressively with increasing impact energy, with the maximum roof displacement reaching 43.7 mm and the maximum displacements of the left and right sides reaching 39.4 and 19.9 mm, respectively. The failure process exhibits a distinct progressive and asymmetric evolution: initial microcracks develop in the roof, followed by intensified damage to the floor and the left side close to the impact source, and finally large roof cracks and separation develop, resulting in complete roadway instability. The AE amplitude and ringing counts increase markedly with impact energy, indicating progressive accumulation and release of damage energy. The main innovation of this study is the integrated characterization of dynamic roadway failure by combining displacement evolution, AE localization and signal characteristics, and macroscopic crack observations, thereby revealing the spatially asymmetric and progressive failure process induced by different impact energies. A soft-structure energy-absorption concept is proposed to transfer concentrated static stress and attenuate dynamic stress waves, providing a potential strategy for improving the impact resistance and stability of deep roadways.