Mining-induced damage characteristics of rock-soil masses under high-intensity mining of shallow coal seam in the Yushen Mining Area

High-intensity mining of shallow coal seams in the Yushen Mining Area readily induces overburden fracturing, fracture development, and coordinated subsidence of the aeolian sand surface. To elucidate the damage transmission mechanism of rock-soil masses under high-intensity mining of shallow coal seam, this paper takes Jinjie Coal Mine as the engineering background and integrates particle-based discrete element modelling, borehole drilling-fluid loss observations, and surface movement monitoring to investigate overburden fracture evolution, displacement transmission, and surface subsidence responses controlled by thick and hard medium-grained sandstone. The results show that the near-field thick and hard medium-grained sandstone exerts a pronounced controlling effect on the upward propagation of mining-induced fractures, leading to distinct stratified damage characteristics in the overburden. The mining-induced microfractures undergo a staged evolution process characterized by incubation, vertical initiation, and overall propagation. Under the combined effects of hard strata breakage and dissipative buffering by the aeolian sand layer, the displacement field of the overburden-surface system exhibits an hourglass-shaped damage pattern, indicating a damage transmission mode characterized by bedrock control, sand-layer buffering, and coordinated surface subsidence. The working face advance rate has a non-monotonic influence on overburden damage; under the thick-bedrock-controlled conditions of Jinjie Coal Mine, the overburden damage degree is relatively low when the advance rate is approximately 20 m/d. Field investigations indicate that the maximum height of the water-conducting fractured zone is approximately 60 m, while the maximum surface subsidence along the strike and dip directions reaches approximately 1 734 mm and 1 593 mm, respectively. The findings provide a reference for overburden-surface damage control in the Yushen Mining Area and in similar shallow coal seam mines.