中远距离煤层群叠加开采双重卸压效应数值分析
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摘要
煤层群开采双重卸压效应的应力分布及卸压范围是制约煤与瓦斯瓦斯高效共采效果的关键因素,为了掌握中远距离煤层群开采双重卸压效应,以朱家店煤矿为例,采用数值模拟研究了对该矿4#、6#煤层叠加开采顶底板应力、位移及塑性区分布与演化特征。结果表明:开采4#煤层时,煤壁应力集中系数为2.0,底板塑性破坏深度及卸压深度分别为20m和62m,顶、底板位移量分别为60mm和30mm;叠加开采6#煤层时,采空区侧煤壁应力集中系数降低为1.7,底板塑性破坏深度及卸压深度分别增加至21m和68m,顶、底板位移量相对减小,顶板垂直应力较小,局部区域应力趋于0,同时,6#煤层顶板竖向位移由上向下转变,且其顶板采动破坏带与4#煤层底板破坏带相沟通,裂隙较发育。最后,经过现场瓦斯抽采工程实践,很好地验证了研究所得的双重卸压强度及范围。
Stress distribution and pressure relief area of double relief effect in coal seams' mining are the key factors which constrain the effective co-production of coal and gas. In order to understand the double relief effect of the mining of coal seam group with middle-distance,this author takes Zhujiadian Coal Mine as an example,its distribution and evolution characteristics of stress,displacement and plastic zone in roof and floor rock under superposed mining of 4#and 6#coal seam were studied by numerical simulation. The results show that stress concentration factor nearby the coal wall is 2. 0,the plastic failure depth and pressure relief depth of the floor strata are 20 m and 62 m respectively,and the displacements of the top and bottom plates are 60 mm and 30 mm respectively as 4#coal seam mining; during 6#coal seam superposed mining,the stress concentration factor of the coal wall near the goaf is reduced to 1. 7,the depth of plastic failure and pressure relief depth of the floor increases to 21 m and 68 m respectively,the displacement of roof and floor is relatively reduced,the vertical stress of roof is small and tends to 0 in some local area. Furthermore,the vertical displacement of the 6#coal seam roof changes from upwards to downwards,and its roof mining-induced failure zone of the coal seam is connected with the floor failure zone of the 4#coal seam,and the fracture is more developed. Finally,the double relief intensity and range are well verified by gas drainage engineering.
Stress distribution and pressure relief area of double relief effect in coal seams' mining are the key factors which constrain the effective co-production of coal and gas. In order to understand the double relief effect of the mining of coal seam group with middle-distance,this author takes Zhujiadian Coal Mine as an example,its distribution and evolution characteristics of stress,displacement and plastic zone in roof and floor rock under superposed mining of 4#and 6#coal seam were studied by numerical simulation. The results show that stress concentration factor nearby the coal wall is 2. 0,the plastic failure depth and pressure relief depth of the floor strata are 20 m and 62 m respectively,and the displacements of the top and bottom plates are 60 mm and 30 mm respectively as 4#coal seam mining; during 6#coal seam superposed mining,the stress concentration factor of the coal wall near the goaf is reduced to 1. 7,the depth of plastic failure and pressure relief depth of the floor increases to 21 m and 68 m respectively,the displacement of roof and floor is relatively reduced,the vertical stress of roof is small and tends to 0 in some local area. Furthermore,the vertical displacement of the 6#coal seam roof changes from upwards to downwards,and its roof mining-induced failure zone of the coal seam is connected with the floor failure zone of the 4#coal seam,and the fracture is more developed. Finally,the double relief intensity and range are well verified by gas drainage engineering.
引文
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[11]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.
[12]薛俊华.近距离高瓦斯煤层群大采高首采层煤与瓦斯共采[J].煤炭学报,2012,37(10):1682-1687.
[13]严国超,胡耀青,宋选民,等.极近距离薄煤层群联合开采常规错距理论及物理模拟究[J].岩石力学与工程学报,2009,28(3):591-597.
[14]程远平,俞启香,袁亮,等.煤与远程卸压瓦斯安全高效共采试验研究[J].中国矿业大学学报,2004,33(2):132-136.
[15]程远平,俞启香,袁亮.上覆远程卸压岩体移动特性及瓦斯抽采技术[J].辽宁工程技术大学学报,2003,22(4):483-486.
[2]刘洪永,程远平,赵长春,等.保护层的分类及判定方法研究[J].采矿与安全工程学报,2010,27(4):468-474.
[3]程远平,周德永,俞启香,等.保护层卸压瓦斯抽采及涌出规律研究[J].采矿与安全工程学报,2006,23(1):12-19.
[4]史元伟,郭潘强,康立军,等.矿井多煤层开采围岩应力分析与设计优化[M].北京:煤炭工业出版社,1995.
[5]郭文兵,刘明举,李化敏,等.多煤层开采采场围岩内部应力光弹力学模拟研究[J].煤炭学报,2001,26(1):8-12.
[6]苏涛,梁冰,李刚,等.晋华宫矿多煤层开采围岩运动规律模拟与试验研究[J].矿业安全与环保,2018,43(2):30-35.
[7]刘林.煤层群多重保护层开采防突技术的研究[J].矿业安全与环保,2001,28(5):1-4.
[8]张敬民,刘贞堂,谢龙.煤层群开采条件下的保护层卸压效应研究[J].煤矿安全,2012,43(9):14-17.
[9]罗勇,祁琦.煤层群多重开采上保护层防突研究[J].防灾减灾工程学报,2005,25(3):244-250.
[10]卢平,袁亮,程桦,等.低透气性煤层群高瓦斯采煤工作面强化抽采卸压瓦斯机理与实验[J].煤炭学报,2010(4):580-585.
[11]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.
[12]薛俊华.近距离高瓦斯煤层群大采高首采层煤与瓦斯共采[J].煤炭学报,2012,37(10):1682-1687.
[13]严国超,胡耀青,宋选民,等.极近距离薄煤层群联合开采常规错距理论及物理模拟究[J].岩石力学与工程学报,2009,28(3):591-597.
[14]程远平,俞启香,袁亮,等.煤与远程卸压瓦斯安全高效共采试验研究[J].中国矿业大学学报,2004,33(2):132-136.
[15]程远平,俞启香,袁亮.上覆远程卸压岩体移动特性及瓦斯抽采技术[J].辽宁工程技术大学学报,2003,22(4):483-486.