Reasonable top coal thickness for large cross-section open-off cut in lower-layer mining

• DOI: 10.3389/feart.2023.1301595
• Publication Date: 2023-12-27T04:11:19Z
• Authors: Shigang Gao; Wengang Du; Yongliang Liu; Jing Chai; Dengyan Gao; Chenyang Ma; Jianhua Chen
• Keywords: slicing mining; top coal thickness; Science; Q; large cross-section open-off cut; optical fiber sensor; field monitoring; 01 natural sciences; 0105 earth and related environmental sciences

The thickness of top coal is the main factor affecting stability large cross section open-off cut under goaf. 1 -2 lower 203 Huojitu Coal Mine was used as background to investigate rational goaf in slicing mining. above simplified into a beam model calculate its plastic zone range with elastoplastic theory influence upper mining and excavating. deformation law different thicknesses studied both simulation experiment numerical simulation. displacement, stress, structure surrounding rock were observed situ using several observation methods. results show that floor face excavation are 2.02 m 1.43 m, maximum 3.45 m. A more than conducive maintaining cut. can be divided roof-fall hazard warning according monitored by distributed optical fiber. When 3.0 3.5 4.0 changes from an exponential linear then logarithmic relationship zone. subsidence trend visibly decreases, only 56% 39% 3 measured DIC (Digital Image Correlation, DIC) consistent average reserved surface hole 12 mm field monitoring. internal 6 mm, shed strain –416 με. slight, indicating 3.5–4.0 reasonable.