Citation: | GE Yang, WANG Hanglong, LI Kegang, LI Ao. Numerical simulation study of overburden collapse law in very close mining area based on FLAC3D[J]. CHINA MINING MAGAZINE, 2023, 32(2): 97-103. DOI: 10.12075/j.issn.1004-4051.2023.02.012 |
The development of overburden collapse height zones and fracture zones in mines is often a channel for water and gas to gush into the mines.In order to study the development of overburden rock collapse height in a large coal mine in Shanxi Province, the 30515 working face and the overburden rock collapse height in the 3-5# coal seam and the overburden rock collapse height in the 2# coal seam are taken as the object of study, and FLAC3D software is used to simulate the vertical displacement distance and stress change of the roof slab when mining the 2# coal seam and the 3-5# coal seam individually and sequentially.The effects of vertical displacement and stress changes of overlying rock seams on the development of seam collapse zones under the two mining conditions are analyzed.The study shows that the maximum displacement of the roof slab in both mining methods is concentrated in the middle range of the mining area, while the maximum stress of the overlying rock seam is concentrated on both sides of the coal pillar.The combined maximum vertical displacement of the roof slab collapse zone when mining 2# coal seam and 3-5# coal seam alone is larger than the maximum vertical displacement of the roof slab when mining successively.The results show that the successive mining of the very close coal seam group disturbs the overlying rock more strongly by the new stress distribution compared with the single seam mining, which accelerates the breakage of the key seam.There exists a large residual strain in the rock body within the collapse zone that can be eliminated by compression, and the height of the collapse zone decreases as the overlying rock layer descends and the rock body in the collapse zone is continuously compacted.