Experimental Study on the Characteristics of Overlying Rock Movement in Mining Area

To reveal the characteristics of overlying rock movement in hard and thick volcanic rock mining areas, a typical volcanic rock occurrence was used as a model. Similar simulation experiments were conducted, combined with on-site monitoring data, to systematically analyze the variations of surface and overlying rock deformation and damage with different mining steps, and compared with the model without hard and thick volcanic rocks. The results showed that compared to the model without hard and thick volcanic rocks, the presence of hard and thick volcanic rocks in the overlying strata led to an increased range of subsidence basin and a decrease in maximum subsidence value. The hard and thick volcanic rocks easily formed larger fractured spaces, which served as the main locations for the accumulation of gas and water in fractures. The “O”-shaped fractured circle formed after the rupture of the hard and thick volcanic rocks provided a favorable pathway for gas outbursts and water surges in the fractures. The rupture of hard and thick volcanic rocks easily triggered intense overlying rock movement and surface subsidence, leading to occurrences of underground and surface disasters such as dynamic ground pressure, outbursts of gas and water in fractures, and damage to surface structures and ecological environments.