采矿与安全工程学报2025，Vol.42Issue(2)：356-370,15.DOI:10.13545／j.cnki.jmse.2023.0304
采空区底板煤岩体时空演化特征及卸压效果研究
Study on spatio-temporal evolution characteristics and unloading effects of coal rock mass in the goaf floor
摘要
Abstract
In order to grasp the spatio-temporal evolution characteristics of floor coal rock mass during unloading and ensure safe and efficient gas extraction from underlying coal seams,it is necessary to ana-lyze the expansion deformation patterns of the floor under multiple influencing factors.In this study,the spatio-temporal evolutions of the stress field and the damage zone under varying advancing distances were examined by numerical simulation.Furthermore,a mining dynamics model was established for ana-lyzing the influences of stress concentration coefficient k,elastic modulus E,floor depth H,and coal seam thickness h on the expansion deformation characteristics of the floor and determining the dominant controlling factors.The results indicate that the coal rock mass below the floor undergoes four stages,i.e.,initial deformation,accelerated deformation,stable deformation,and final deformation.As the working face advances periodically,the floor is damaged in the shape of an inverted"triangle".A fully unloaded area is formed near the coal wall and the open-off cut,and the area near the working face is unloaded significantly and extensively.In the meantime,a circular compaction zone is gradually formed around the goaf center.The expansion deformation of the coal rock mass below the floor presents an"M"shape that is high at both ends and low in the middle.The expansion deformation becomes milder at a larger distance from the goaf.The physical characteristics of coal seams result from the interaction of surrounding geological environment,and the interlayer distance His one of the main factors affecting the expansion deformation of the coal rock mass.Onsite gas pressure monitoring in two underlying coal seams demonstrates that,as the working face approaches or moves away from the borehole,the gas pressure along the strike and dip directions generally increases first,then decreases,and finally stabilizes until the completion of unloading.Moreover,as the floor depth increases,the peak gas pressure gradual-ly rises to 0.4-0.5 MPa and its unloading effect weakens.This study can serve as reference for the lay-out of pressure relief gas extraction from underlying coal seams.关键词
底板应力/时空演化/膨胀变形/卸压范围/膨胀率Key words
floor stress/spatio-temporal evolution/expansion deformation/unloading range/expansion rate分类
矿业与冶金引用本文复制引用
党嘉鑫,涂敏,张向阳,赵庆冲..采空区底板煤岩体时空演化特征及卸压效果研究[J].采矿与安全工程学报,2025,42(2):356-370,15.基金项目
安徽省高效协同创新项目(GXXT-2020-056) （GXXT-2020-056）
国家自然科学基金项目(52074008) （52074008）
