Physical Experiment and Numerical Simulation Study on Balanced Mining Based on the 110 Mining Method in Shallow-Buried Thin Bedrock with a Thick Weathered Layer

Surface subsidence and ecological destruction caused by underground coal mining have become hot topics in mining research. To reduce the negative externalities of mining activities, China has proposed a balanced mining theory based on the 110 coal mining method, which is still in the hypothesis stage, and its effectiveness remains to be verified. This paper constructs a new analogous material physical model test and combines it with theoretical analysis to deeply explore the balanced mining effect of the 110 coal mining method in shallow-buried thin bedrock with a thick weathered layer. At the same time, a matching numerical model is established to verify the accuracy of the physical model test results. The balanced mining characteristics of the 110 coal mining method are analyzed from three aspects: overburden movement mode, settlement displacement, and fracture development. First, unlike traditional longwall mining, the 110 coal mining method forms a new adequately supported, bending transition, protected three zone. Second, it transforms the traditional caving zone into an adequately supported zone, eliminates the fractured zone, and expands the protected area, enhancing the protection of the overlying rock layer. Finally, by increasing the roof destruction height, this method promotes the fragmentation of the cut roof rock layer. Consequently, fracture development in the adequately supported zone increases, while fracture extension in other areas is reduced. This process enhances the rock expansion effect, minimizes surface subsidence, and protects the ecological environment. The results show that the 110 coal mining method enhances rock layer expansion through roof-cutting and pressure-relief technology and achieves balanced mining with a solvable mining damage invariant equation using the characteristics of gangue. The research results provide a reference for similar geotechnical engineering experiments and are significant for achieving green, safe, and balanced coal mining.