摘要
我国西部神府东胜煤田主要赋存浅埋近距煤层,煤层埋藏浅,覆岩上部厚松散层大范围分布,近距煤层开采导致覆岩与地表裂缝发育严重,加剧了原本脆弱的生态环境进一步恶化。为探究浅埋近距煤层开采覆岩与地表采动裂缝发育规律,掌握其控制方法,以柠条塔煤矿1-2煤层和2-2煤层开采为背景,结合实测统计分析、物理模拟和分形理论,掌握浅埋顶部单一煤层开采和重复采动下覆岩与地表裂缝发育特征,揭示煤柱布置对裂缝发育的控制作用。研究表明,煤层开采导致的地表裂缝可分为平行于工作面的动态裂缝和工作面开采边界地表裂缝(切眼边界侧地表裂缝和区段煤柱侧地表裂缝),动态裂缝在开采后能够实现自修复,工作面开采边界的地表裂缝不能自修复。下煤层开采区段煤柱侧覆岩与地表采动裂缝发育严重,其与区段煤柱错距密切相关。1^(-2)煤层开采后,基岩垮落角为60°,土层垮落角为65°,边界煤柱侧地表裂缝的宽度为0.26 m。下部2^(-2)煤层开采,煤柱叠置、错距20、40 m时,区段煤柱侧覆岩采动裂缝宽度分别为0.81、0.45和0.22 m,地表裂缝宽度分别为0.65、0.30和0.12 m。通过确定合理煤柱布置方式,能够有效控制覆岩和地表采动裂缝的发育程度,据此确定柠条塔煤矿1^(-2)煤层和2^(-2)煤层开采的合理煤柱错距应大于40 m。
The Shenfu-Dongsheng Coalfield in western country mainly occurs in shallow close multi-seam,and the thick loose layers on the overlying rock are distributed in a wide range.Mining in shallow-contiguous seams results in serious development of overlying rock and surface fractures,which aggravates the deterioration of the originally fragile ecological environment.In order to explore the mining-induced overburden and surface fractures development characteristics in shallow shallow-contiguous seams,and obtain its control method.Taking No.1^(-2) seam and No.2^(-2) seam mining in Ningtiaota Coal Mine as background,this paper obtains the development characteristics of fractures in shallow single seam mining and repeated mining through in-site statistic analysis,physical simulation and fractal theory.Besides,the control effect of pillar staggered distance to mining-induced fractures is revealed.The results show that the mining-induced surface fractures can be divided into two types,one is dynamic fractures which are parallel to the working face,and another is mining boundary surface fractures which contain open-off boundary surface fractures and pillar boundary surface fractures.The dynamic fractures can realize self-repairing after mining,while the mining boundary surface fractures can not realize self-repairing.After lower seam mining,the pillar boundary overburden and surface fractures development seriously,which are closely related to pillar staggered distance.After No.1^(-2) seam mining,the bedrock caving angle is 60°,and the soil layer caving angle is 65°,the width of surface fracture along coal pillar,0.26 m.After lower No.2^(-2) seam mining,when the pillars are aligned,with pillar staggered distance of 20 m and 40 m,the width of overburden fractures are 0.81 m,0.45 m and 0.22 m respectively,and the width of surface fractures are 0.65 m,0.30 m and 0.12 m.Through determining the reasonable pillar staggered distance,development of the overburden and surface fractures can be controlled effectively.Finally,the reasonable pillar staggered distance should be greater than 40m in No.1^(-2) and No.2^(-2) seams mining in Ningtiaota Coal Mine.
作者
曹健
黄庆享
CAO Jian;HUANG Qingxiang(Institute of Mining and Coal,Inner Mongolia University of Science and Technology,Baotou 014010,China;School of Energy,Xi’an University of Science and Technology,Xi’an 710054,China)
出处
《煤田地质与勘探》
CSCD
北大核心
2021年第4期213-220,共8页
Coal Geology & Exploration
基金
国家自然科学基金面上项目(51674190,52074211)
西安科技大学优秀博士学位论文培育计划项目(PY18002)。
关键词
浅埋近距煤层
覆岩采动裂缝
地表采动裂缝
煤柱错距
shallow-contiguous seams
overburden mining-induced fractures
surface mining-induced fractures
pillar staggered distance
