浅埋煤层群覆岩与地表裂隙发育规律和形成机理研究
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摘要
浅埋煤层群高强度开采对地表的损害严重。为了研究煤层群开采裂隙(缝)发育规律和形成机理,以陕北典型浅埋煤层群开采为工程背景,采用物理模拟、数值计算和现场实测相结合的方法,得出覆岩裂隙主要为采空区边缘向上发育的上行裂隙和垮落区内的离层裂隙。地表裂隙(缝)主要为开切眼和停采线永久边界裂隙、随工作面推进周期性出现的平行裂缝、沿工作面间的煤柱边界裂隙。沿工作面间的煤柱边界裂隙的分布长度最大,是地表裂隙控制的主要对象。煤层群下煤层工作面来压步增大18%～30%,下煤层开采地表下沉系数有所减小。煤层群重复采动后边界裂隙最发育,且受上下煤柱位置的显著影响。通过合理布置煤柱,可以降低煤柱导致的应力集中,减轻不均匀沉降和地表裂缝发育。
In order to study the coal mining cracks(or fissure) formation and development mechanism, taking the typical shallow coal seam group mining in Northern Shaanxi as the engineering background and using the method of physical simulation, numerical calculation and field measurement, it is concluded that the mining induced cracks in overburden are mainly the upward cracks along the gob edge and roof separation cracks in the caving zone. The surface cracks are mainly the permanent boundary cracks of open cut and stop mining line, periodic parallel cracks along with mining face and sectional coal pillar boundary cracks. The coal pillar boundary cracks which are the longest in distribution is the main object of the crack control. Under the coal seam group mining, the roof caving step increase by 18%-30%, and the subsidence coefficient of the ground surface is reduced. After the repeated mining of the coal seams, the boundary cracks are easily developed and are influenced by the position of the upper and lower coal pillars. By reasonably arranging the coal pillars, the stress concentration caused by the coal pillar can be decreased, the uneven surface subsidence and cracks can be reduced.
In order to study the coal mining cracks(or fissure) formation and development mechanism, taking the typical shallow coal seam group mining in Northern Shaanxi as the engineering background and using the method of physical simulation, numerical calculation and field measurement, it is concluded that the mining induced cracks in overburden are mainly the upward cracks along the gob edge and roof separation cracks in the caving zone. The surface cracks are mainly the permanent boundary cracks of open cut and stop mining line, periodic parallel cracks along with mining face and sectional coal pillar boundary cracks. The coal pillar boundary cracks which are the longest in distribution is the main object of the crack control. Under the coal seam group mining, the roof caving step increase by 18%-30%, and the subsidence coefficient of the ground surface is reduced. After the repeated mining of the coal seams, the boundary cracks are easily developed and are influenced by the position of the upper and lower coal pillars. By reasonably arranging the coal pillars, the stress concentration caused by the coal pillar can be decreased, the uneven surface subsidence and cracks can be reduced.
引文
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[14]王文学,王四巍,刘海宁,等.采后覆岩裂隙岩体应力恢复的时空特征[J].采矿与安全工程学报,2017,34(1):127-133.WANG Wenxue,WANG Siwei,LIU Haining,et al.The space and time characteristics of the cover stress re-establishment of the fractured rock mass in the goaf after coal mining[J].Journal of Mining&Safety Engineering,2017,34(1):127-133.
[15]程志恒,齐庆新,李宏艳,等.近距离煤层群叠加开采采动应力-裂隙动态演化特征实验研究[J].煤炭学报,2016,41(2):367-375.CHENG Zhiheng,QI Qingxin,LI Hongyan,et al.Evolution of the superimposed mining induced stress-fissure field under extracting of close distance coal seam group[J].Journal of China Coal Society,2016,41(2):367-375.
[16]刘辉,邓喀中,雷少刚,等.采动地裂缝动态发育规律及治理标准探讨[J].采矿与安全工程学报,2017,34(5):884-890.LIU Hui,DENG Kazhong,LEI Shaogang,et al.Dynamic developing law and governance standard of ground fissures caused by underground mining[J].Journal of Mining&Safety Engineering,2017,34(5):884-890.
[17]黄庆享,杜君武,刘寅超.浅埋煤层群工作面合理区段煤柱留设研究[J].西安科技大学学报,2016,36(1):19-23.HUANG Qingxiang,DU Junwu,LIU Yinchao.Study on section coal pillar of group mining in shallow buried coal seams[J].Journal of Xi’an University of Science and Technology,2016,36(1):19-23.
[2]许家林,钱鸣高.岩层采动裂隙分布在绿色开采中的应用[J].中国矿业大学学报,2004,33(2):141-144.XU Jialin,QIAN Minggao.Study and application of mining-induced fracture distribution in green mining[J].Journal of China University of Mining&Technology,2004,33(2):141-144.
[3]黄庆享.浅埋煤层的矿压特征与浅埋煤层定义[J].岩石力学与工程学报,2002,21(8):1174-1177.HUANG Qingxiang.Ground pressure behavior and definition of shallow seams[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(8):1174-1177.
[4]刘辉,何春桂,邓喀中,等.开采引起地表塌陷型裂缝的形成机理分析[J].采矿与安全工程学报,2013,30(3):380-384.LIU Hui,HE Chungui,DENG Kazhong,et al.An analysis of forming mechanism of collapsing ground fissure caused by mining[J].Journal of Mining&Safety Engineering,2013,30(3):380-384.
[5]胡振琪,王新静,贺安民.风积沙区采煤沉陷地裂缝分布特征与发生发育规律[J].煤炭学报,2014,39(1):11-18.HU Zhenqi,WANG Xinjing,HE Anmin.Distribution characteristic and development rules of ground fissures due to coal mining in windy and sandy region[J].Journal of China Coal Society,2014,39(1):11-18.
[6]范立民,张晓团,向茂西,等.浅埋煤层高强度开采区地裂缝发育特征-以陕西榆神府矿区为例[J].煤炭学报,2015,40(6):1442-1447.FAN Limin,ZHANG Xiaotuan,XIANG Maoxi,et al.Characteristics of ground fissure development in high intensity mining area of shallow seam in Yushenfu coal field[J].Journal of China Coal Society,2015,40(6):1442-1447.
[7]黄庆享,夏小刚.采动岩层与地表移动的“四带”划分研究[J].采矿与安全工程学报,2016,33(3):393-397.HUANG Qingxiang,XIA Xiaogang.Division of“four zones”in mining strata and surface movement[J].Journal of Mining&Safety Engineering,2016,33(3):393-397.
[8]杨泽元,范立民,许登科,等.陕北风沙滩地区采煤塌陷裂缝对包气带水分运移的影响:模型建立[J].煤炭学报,2017,42(1):155-161.YANG Zeyuan,FAN Limin,XU Dengke,et al.Influence of fissures due to coal mining on moisture transportation in the vadose zone in the blown-sand region of the northern shaanxi province:Model establishment[J].Journal of China Coal Society,2017,42(1):155-161.
[9]王双明,杜华栋,王生全.神木北部采煤塌陷区土壤与植被损害过程及机理分析[J].煤炭学报,2017,42(1):17-26.WANG Shuangming,DU Huadong,WANG Shengquan.Analysis of damage process and mechanism for plant community and soil properties at northern Shenmu subsidence mining area[J].Journal of China Coal Society,2017,42(1):17-26.
[10]黄庆享.浅埋煤层保水开采岩层控制研究[J].煤炭学报,2017,42(1):50-55.HUANG Qingxiang.Research on roof control of water conservation mining in shallow seam[J].Journal of China Coal Society,2017,42(1):50-55.
[11]徐乃忠,高超,倪向忠,等.浅埋深特厚煤层综放开采地表裂缝发育规律研究[J].煤炭科学技术,2015,43(12):124-127.XU Naizhong,GAO Chao,NI Xiangzhong,et al.Study on surface cracks law of fully-mechanized top coal caving mining in shallow buried depth and extra thick seam[J].Coal Science and Technology,2015,43(12):124-127.
[12]薛东杰,周宏伟,任伟光,等.浅埋深薄基岩煤层组开采采动裂隙演化及台阶式切落形成机制[J].煤炭学报,2015,40(8):1746-1752.XUE Dongjie,ZHOU Hongwei,REN Weiguang,et al.Stepped shearing-induced failure mechanism and cracks propagation of overlying thin bedrocks in shallow deep coal seams mining[J].Journal of China Coal Society,2015,40(8):1746-1752.
[13]胡永忠,刘长郄,刘长友,等.煤层群混合开采采动裂隙发育规律研究[J].采矿与安全工程学报,2015,32(3):396-400.HU Yongzhong,LIU Changqie,LIU Changyou,et al.Development regularity of mining-induced fractures in mixed mining of coal group[J].Journal of Mining&Safety Engineering,2015,32(3):396-400.
[14]王文学,王四巍,刘海宁,等.采后覆岩裂隙岩体应力恢复的时空特征[J].采矿与安全工程学报,2017,34(1):127-133.WANG Wenxue,WANG Siwei,LIU Haining,et al.The space and time characteristics of the cover stress re-establishment of the fractured rock mass in the goaf after coal mining[J].Journal of Mining&Safety Engineering,2017,34(1):127-133.
[15]程志恒,齐庆新,李宏艳,等.近距离煤层群叠加开采采动应力-裂隙动态演化特征实验研究[J].煤炭学报,2016,41(2):367-375.CHENG Zhiheng,QI Qingxin,LI Hongyan,et al.Evolution of the superimposed mining induced stress-fissure field under extracting of close distance coal seam group[J].Journal of China Coal Society,2016,41(2):367-375.
[16]刘辉,邓喀中,雷少刚,等.采动地裂缝动态发育规律及治理标准探讨[J].采矿与安全工程学报,2017,34(5):884-890.LIU Hui,DENG Kazhong,LEI Shaogang,et al.Dynamic developing law and governance standard of ground fissures caused by underground mining[J].Journal of Mining&Safety Engineering,2017,34(5):884-890.
[17]黄庆享,杜君武,刘寅超.浅埋煤层群工作面合理区段煤柱留设研究[J].西安科技大学学报,2016,36(1):19-23.HUANG Qingxiang,DU Junwu,LIU Yinchao.Study on section coal pillar of group mining in shallow buried coal seams[J].Journal of Xi’an University of Science and Technology,2016,36(1):19-23.