基于巨厚岩层-煤柱协同变形的煤柱稳定性
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摘要
采前煤柱稳定性研究是工作面冲击危险性评估和开采方案设计的关键。以山东某矿深井巨厚砾岩条件工作面开采遗留煤柱为背景,采用案例调研、理论分析、数值模拟和工程实践等方法,对巨厚岩层-煤柱协同变形机制及其煤柱稳定性进行了研究,建立了巨厚岩层-煤柱协同变形的简化力学模型,探讨了引起煤柱变形的主要应力来源和变形形式,推导了在协同变形条件下煤柱的应力-应变关系。以此为基础,综合煤柱煤体应力、围岩稳定性和变形特征等条件,提出了煤柱整体失稳的力学判据。研究结果表明:巨厚岩层-煤柱失稳诱发冲击与煤柱的位置、尺寸和上覆岩层运动或变形关系密切,上覆岩层运动或变形是诱发煤柱失稳的动力因素;巨厚岩层-煤柱的变形主要包括受集中力F压迫的协同挠曲压缩变形和受集中力G作用的重力沉降变形,二者保持内在协调性;巨厚岩层下煤柱整体失稳的工程判据为煤柱煤体平均支承应力p超过其平均极限支承强度R_c(p≥R_c);评估得到遗留的50 m煤柱具有强冲击危险性,并通过优化开采设计,取得了良好的效果。该研究成果对相似条件煤柱留设及其稳定性分析具有参考意义。
It is essential to assess the stability of coal pillar before mining for the evaluation of its rockburst risk and determination of mining schemes. Based on the geological conditions of a deep coal mine in Shandong province, China, these methods including in-situ case study, theoretical analysis, numerical simulation and engineering practice were adopted to evaluate the stability of the coal pillar with thick conglomerate upper strata. The deformation of conglomerate strata and coal pillar was analysed on the basis of a simplified mechanical model. We investigated the primary source of stress that caused coal pillar deformation and its deformation form, and obtained the stress-strain curve of coal pillar. Then, by considering the stress in coal pillar, surrounding rock stability and deformation, a mechanical criterion of coal pillar failure was proposed. It indicates that the location and size of a coal pillar, as well as the deformation of conglomerate upper strata, have significant impacts on the failure of coal pillar. The deformation of upper strata results in dynamic loading on the coal pillar. The deformation of coal pillar mainly includes collaborative deflection compression deformation induced by the concentration load F and the gravity settlement deformation caused by the concentration load G. The coal pillar failures when the supporting stress(p) is greater than its ultimate strength(R_c). It is found that the coal pillar with 50 m width has a high risk of rockburst, the risk decreased by optimising the mining scheme and achieved good effects. The results of this study are of significance for the analysis of the stability of coal pillar with similar conditions.
It is essential to assess the stability of coal pillar before mining for the evaluation of its rockburst risk and determination of mining schemes. Based on the geological conditions of a deep coal mine in Shandong province, China, these methods including in-situ case study, theoretical analysis, numerical simulation and engineering practice were adopted to evaluate the stability of the coal pillar with thick conglomerate upper strata. The deformation of conglomerate strata and coal pillar was analysed on the basis of a simplified mechanical model. We investigated the primary source of stress that caused coal pillar deformation and its deformation form, and obtained the stress-strain curve of coal pillar. Then, by considering the stress in coal pillar, surrounding rock stability and deformation, a mechanical criterion of coal pillar failure was proposed. It indicates that the location and size of a coal pillar, as well as the deformation of conglomerate upper strata, have significant impacts on the failure of coal pillar. The deformation of upper strata results in dynamic loading on the coal pillar. The deformation of coal pillar mainly includes collaborative deflection compression deformation induced by the concentration load F and the gravity settlement deformation caused by the concentration load G. The coal pillar failures when the supporting stress(p) is greater than its ultimate strength(R_c). It is found that the coal pillar with 50 m width has a high risk of rockburst, the risk decreased by optimising the mining scheme and achieved good effects. The results of this study are of significance for the analysis of the stability of coal pillar with similar conditions.
引文
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[9]王春秋,高立群,陈绍杰,等.条带煤柱长期承载能力实测研究[J].采矿与安全工程学报,2013,30(6):779-804.WANG Chun-qiu,GAO Li-qun,CHEN Shao-jie,et al.Field research on long-term bearing capacity of strip pillar[J].Journal of Mining&Safety Engineering,2013,30(6):779-804.
[10]张广超,何富连.大断面综放沿空巷道煤柱合理宽度与围岩控制[J].岩土力学,2016,37(6):1721-1728.ZHANG Guang-chao,HE Fu-lian.Pillar width determination and surrounding rocks control of gob-side entry with large cross-section and fully-mechanized mining[J].Rock and Soil Mechanics,2016,37(6):1721-1728.
[11]张明.厚硬岩层矿井矿震与冲击复合动力灾害防控研究[D].北京:北京科技大学,2017.ZHANG Ming.Study on prevention and control of complex dynamic disasters of mine quake and rock burst under hard-thick strata[D].Beijing:University of Science and Technology Beijing,2017.
[12]MIAO H X,JIANG F X,SONG X J,et al.Tomographic inversion formicroseismic source parameters in mining[J].Applied Geophysics,2012,9(3):341-348.
[13]蒋金泉,张培鹏,秦广鹏,等.高位主关键层破断失稳及微震活动分析[J].岩土力学,2015,36(12):3567-3575.JIANG Jin-quan,ZHANG Pei-peng,QIN Guang-peng,et al.Analysis of destabilized fracture and microseismic activity of high-located main key strata[J].Rock and Soil Mechanics,2015,36(12):3567-3575.
[14]蒋金泉,王普,武泉林,等.上覆高位岩浆岩下离层空间的演化规律及其预测[J].岩土工程学报,2015,37(10):1769-1779.JIANG Jin-quan,WANG Pu,WU Quan-lin,et al.Evolution laws and prediction of separated stratum space under overlying high-position magmatic rocks[J].Chinese Journal of Geotechnical Engineering,2015,37(10):1769-1779.
[15]张明,姜福兴,李克庆,等.巨厚岩层-煤柱系统协调变形及其稳定性研究[J].岩石力学与工程学报,2017,36(2):326-334.ZHANG Ming,JIANG Fu-xing,LI Ke-qing,et al.Study of the compatible deformation and stability of the system of super thick strata and coal pillars[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(2):326-334.
[16]苏承东,翟新献,李永明.煤样三轴压缩下变形和强度分析[J].岩石力学与工程学报,2006,25(增刊1):2963-2968.SU Cheng-dong,ZHAI Xin-xian,LI Yong-ming.Study on deformation and strength of coal samples in triaxial compression[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(Supp.1):2963-2968.
[17]刘金海,姜福兴,孙广京,等.强排煤粉防治冲击地压的机制与应用[J].岩石力学与工程学报,2014,33(4):748-754.LIU Jin-hai,JIANG Fu-xing,SUN Guang-jing,et al.Mechanism of intensive venting pulverized coal to prevent coal burst and its application[J].Chinese Journal of rock Mechanics and Engineering,2014,33(4):748-754.
[18]姜福兴,舒凑先,王存文.基于应力叠加回采工作面冲击危险性评价[J].岩石力学与工程学报,2015,34(12):2428-2435.JIANG Fu-xing,SHU Cou-xian,WANG Cun-wen.Impact risk appraisal on stope faces based on stress superimposition[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(12):2428-2435.
[19]煤炭工业部.冲击地压煤层安全开采暂行规定[S].北京:煤炭工业部,1987.Ministry of Coal Industry.The interim provisions of the safe exploitation in coal seams with rockburst tendencies[S].Beijing:Ministry of Coal Industry,1987.
[2]DOU L M,HE X Q,HE H,et al.Spatial structure evolution of overlying strata and inducing mechanism of rockburst in coal mine[J].Transactions of Nonferrous Metals Society of China,2014,24(4):1255-1261.
[3]张明,姜福兴,李克庆,等.重复采动停采边界关键层失稳诱发灾害研究[J].中国矿业大学学报,2016,45(5):915-922.ZHANG Ming,JIANG Fu-xing,LI Ke-qing,et al.Study of disasters induced by key strata instability near stopping boundary in the process of repeated coal mining[J].Journal of China University of Mining and Technology,2016,45(5):915-922.
[4]章梦涛,徐曾和,潘一山,等.冲击地压和突出的统一失稳理论[J].煤炭学报,1991,16(4):48-53.ZHANG Meng-tao,XU Zeng-he,PAN Yi-shan,et al.A united instability theory on coal(rock)burst and outburst[J].Journal of China Coal Society,1991,16(4):48-53.
[5]王连国,缪协兴.煤柱失稳的突变学特征研究[J].中国矿业大学学报,2007,36(1):7-11.WANG Lian-guo,MIAO Xie-xing.The destabilization of the coal pillar mutant[J].Journal of China University of Mining and Technology,2007,36(1):7-11.
[6]陈庆发,古德生,周科平,等.对称协同开采人工矿柱失稳的突变理论分析[J].中南大学学报,2012,43(6):2338-2342.CHEN Qing-fa,GU De-sheng,ZHOU Ke-ping,et al.Analysis of catastrophe theory for artificial pillar instability in symmetric synergistic mining[J].Journal of Central South University,2012,43(6):2338-2342.
[7]曹胜根,曹洋,姜海军.块段式开采区段煤柱突变失稳机制研究[J].采矿与安全工程学报,2014,31(6):907-913.CAO Sheng-gen,CAO Yang,JIANG Hai-jun.Research on catastrophe instability mechanism of section coal pillars in block mining[J].Journal of Mining&Safety Engineering,2014,31(6):907-913.
[8]王金安,李大钟,尚新春.采空区坚硬顶板流变破断力学分析[J].北京科技大学学报,2011,33(2):142-148.WANG Jin-an,LI Da-zhong,SHANG Xin-chun.Mechanics analysis on creep fracture of strong roof strata above mined-out area[J].Journal of University of Science and Technology Beijing,2011,33(2):142-148.
[9]王春秋,高立群,陈绍杰,等.条带煤柱长期承载能力实测研究[J].采矿与安全工程学报,2013,30(6):779-804.WANG Chun-qiu,GAO Li-qun,CHEN Shao-jie,et al.Field research on long-term bearing capacity of strip pillar[J].Journal of Mining&Safety Engineering,2013,30(6):779-804.
[10]张广超,何富连.大断面综放沿空巷道煤柱合理宽度与围岩控制[J].岩土力学,2016,37(6):1721-1728.ZHANG Guang-chao,HE Fu-lian.Pillar width determination and surrounding rocks control of gob-side entry with large cross-section and fully-mechanized mining[J].Rock and Soil Mechanics,2016,37(6):1721-1728.
[11]张明.厚硬岩层矿井矿震与冲击复合动力灾害防控研究[D].北京:北京科技大学,2017.ZHANG Ming.Study on prevention and control of complex dynamic disasters of mine quake and rock burst under hard-thick strata[D].Beijing:University of Science and Technology Beijing,2017.
[12]MIAO H X,JIANG F X,SONG X J,et al.Tomographic inversion formicroseismic source parameters in mining[J].Applied Geophysics,2012,9(3):341-348.
[13]蒋金泉,张培鹏,秦广鹏,等.高位主关键层破断失稳及微震活动分析[J].岩土力学,2015,36(12):3567-3575.JIANG Jin-quan,ZHANG Pei-peng,QIN Guang-peng,et al.Analysis of destabilized fracture and microseismic activity of high-located main key strata[J].Rock and Soil Mechanics,2015,36(12):3567-3575.
[14]蒋金泉,王普,武泉林,等.上覆高位岩浆岩下离层空间的演化规律及其预测[J].岩土工程学报,2015,37(10):1769-1779.JIANG Jin-quan,WANG Pu,WU Quan-lin,et al.Evolution laws and prediction of separated stratum space under overlying high-position magmatic rocks[J].Chinese Journal of Geotechnical Engineering,2015,37(10):1769-1779.
[15]张明,姜福兴,李克庆,等.巨厚岩层-煤柱系统协调变形及其稳定性研究[J].岩石力学与工程学报,2017,36(2):326-334.ZHANG Ming,JIANG Fu-xing,LI Ke-qing,et al.Study of the compatible deformation and stability of the system of super thick strata and coal pillars[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(2):326-334.
[16]苏承东,翟新献,李永明.煤样三轴压缩下变形和强度分析[J].岩石力学与工程学报,2006,25(增刊1):2963-2968.SU Cheng-dong,ZHAI Xin-xian,LI Yong-ming.Study on deformation and strength of coal samples in triaxial compression[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(Supp.1):2963-2968.
[17]刘金海,姜福兴,孙广京,等.强排煤粉防治冲击地压的机制与应用[J].岩石力学与工程学报,2014,33(4):748-754.LIU Jin-hai,JIANG Fu-xing,SUN Guang-jing,et al.Mechanism of intensive venting pulverized coal to prevent coal burst and its application[J].Chinese Journal of rock Mechanics and Engineering,2014,33(4):748-754.
[18]姜福兴,舒凑先,王存文.基于应力叠加回采工作面冲击危险性评价[J].岩石力学与工程学报,2015,34(12):2428-2435.JIANG Fu-xing,SHU Cou-xian,WANG Cun-wen.Impact risk appraisal on stope faces based on stress superimposition[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(12):2428-2435.
[19]煤炭工业部.冲击地压煤层安全开采暂行规定[S].北京:煤炭工业部,1987.Ministry of Coal Industry.The interim provisions of the safe exploitation in coal seams with rockburst tendencies[S].Beijing:Ministry of Coal Industry,1987.