Research into Acoustic Emission Monitoring in Similar Simulation of Coal Mining Under Roof-Confined Water Drainage

The combined disaster of roof water and rock burst occurs while working faces with roof-confined water during the mining process, and poses a significant threat to mine production safety. The drainage of confined water from the coal seam roof is a key factor contributing to the risk of rock bursts during mining. To examine the impact of the drainage of roof-confined water on coal seam mining, a similar simulation method was employed to study fracture development, rock layer displacement, and fracture evolution laws in the working face under a drainage condition. The results indicated that the actual fracture height of the model aligns with the theoretical fracture height, and the model fractures extend through the drainage area. The displacement of the rock layer below the drainage area exhibits a distinct step-like distribution at the drainage boundary, whereas the displacement of the rock layer above the drainage area forms a “V” shape distribution. The gradient on the drainage side is significantly smaller than that of the non-drainage area. The number of acoustic emission events and amount of energy concentration is the highest at the boundary of the drainage module. In terms of event occurrence, the temporal concentration is 1.35 times greater than the space concentration, while in terms of energy, the temporal concentration is 2.5 times greater than the space concentration. The findings hold important theoretical and practical significance for ensuring the safety of roof water-rich working faces in mining.