A Study on Stress Evolution Patterns and Energy Fields in High-Seam-Height Working Faces in Folded Structures

To address the alternating high- and low-stress cycles observed during the analysis of stress evolution and energy field distribution in the folded structural zone of Working Face No. 2 at a certain mine, a three-dimensional geological numerical model was established using Rhino+HyperMesh, incorporating the geological characteristics of the working face. Additionally, a dual-yield model for the goaf was incorporated into the analysis to accurately capture rock behavior. The analysis reveals that in the folded structural zone, the stress at the advance supports reaches its maximum at each inflection point, when the waste rock in the goaf also exhibits significant hardening behavior. Specifically, during the synclinal upward mining stage, the abutment stress reaches 7.6 MPa. In contrast, stress values reach their minimum at the ridge and trough points. In these inflection points, concentrated stresses are also observed on both sides of the coal face in the goaf. Notably, the stress in the haulage gate, due to its greater curvature, is higher than that in the return air drift. Furthermore, the strain energy peaks at the hinge point between the drift and the axis of the anticline. This concentration of strain energy occurs in areas highly prone to roof collapse, and notably, it is maximized where these three factors intersect.