Impact of overburden movement evolution on disasters in shallow-buried coal seam mining in ravine regions

In order to further investigate the impact of overburden movement evolution on disasters in shallow-buried coal seam mining in ravine regions, first mining face 113101 of Kunyuan Coal Mine in Yushen Mining Area was set as the engineering background. With the aid of numerical simulation and physical modeling tests in shallow-buried coal seam mining in ravine regions, the study analyzed the stress and dynamic displacement evolution of overburden, as well as the characteristics of fracture, and crack development. The disaster characteristics and relevant interaction relationship at ravine-passing process of mining were preliminary revealed, and the comprehensive controlling measure was put forward. The results showed that the downhill section of ravine was in compression state whilst the uphill section was in tension state when the ravine-passing mining were under way. Displacement at the ravine bottom was the largest, followed by the uphill section and the downhill section. The stress concentration is formed in the lower part of the downhill section and the ravine bottom of ravine No.2, the lower part of the uphill section and the ravine bottom of ravine No.1, and the displacement reaches the maximum. The peak horizontal stress is 17. 4 MPa and 14. 5 MPa, and the maximum displacement is 1. 7 m and 1. 0 m. When the working face is pushed to the downhill of the ravine area, the periodic weighting interval is about twice that of the uphill. The area of the overburden complete area in the downhill is large, and the load is transmitted to the working face support to cause the supports crushing phenomenon. Advancing to the area of uphill, the thickness of overburden rock increases, and the development of tensile cracks is obvious, which is easy to lead to ravine-induced landslide. It advances to the ravine bottom area, the roof collapses to form a collapse cracks, which is easy to induce supports crushing and water-sand inrush disasters in the working face. Different disasters are interrelated, the ravine-induced landslide inhibits the water-sand inrush of the working face but promotes the roof caving and supports crushing disaster. The roof caving and supports crushing also promotes the water-sand inrush and the ravine-induced landslide disasters. According to the area and action characteristics of overburden disasters, the comprehensive control measures such as intercepting surface water in the upstream, pre-splitting the middle and upper strata in the downhill section, slope reinforcement in the uphill section, grouting reinforcement at the bottom of the ditch and the slope toe of the uphill section are put forward, which provided a corresponding research foundation for safe and efficient mining in the working face. © 2024 China University of Mining and Technology. All rights reserved.