煤层深孔聚能爆破有效致裂范围探讨
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摘要
在对煤层深孔聚能爆破致裂分区研究的基础上,针对聚能爆破煤层裂隙扩展特征及范围进行了数值模拟研究.结果表明,炮孔周围可划分为爆破压碎区、爆破裂隙区和弹性变形区,根据裂隙类型及裂隙数目的差异,爆破裂隙区又可划分为裂隙密集区和主裂隙扩展区.受聚能装药结构的影响,压碎区的范围呈聚能罩开口方向小于其他方向的类椭圆状;裂隙密集区和主裂隙扩展区的范围均呈聚能罩开口方向大于其他方向的类椭圆状.煤层深孔聚能爆破致裂增透工程试验发现,随着远离炮孔,各个观察孔内瓦斯体积分数增幅受聚能爆破的影响呈"强-中-弱"阶梯状变化,与所构建的聚能爆破致裂分区模型比较一致,即聚能爆破载荷下煤层裂隙具有明显的分区特征,压碎区、裂隙密集区和主裂隙扩展区组成了煤层深孔聚能爆破的有效致裂范围.
Deep-hole directional cumulative-blasting cracking technology has unique advantages for improving coal seam permeability. This paper was concerned with the range of the effective fracture zone under cumulative blasting using a linear-shaped charge in a coal seam. Based on the analysis of the mechanism of the directional cumulative-blasting in coal seams,the response characteristics of the coal under the coupled effects of the blasting-induced shock wave,stress wave,detonation gas and the energy-cumulative effect,and the partition characteristics of the crack in the cumulative-blasting-affected area were studied by theoretical analysis; moreover,a numerical analysis model of cumulative blasting was established,and the propagation distribution characteristics and range of coal seam fracture under cumulative blasting were investigated through numerical simulation. The results of the theoretical analysis and simulation show that the cumulative-blasting-affected area can be divided into crushed,crack,and elastic-deformation zones; further,the crack zone can be divided into crack-intensive and main crack-propagation zones according to the type and number of cracks. Additionally,a partition model for the influence of deep-hole cumulative blasting with linear-shaped charge in coal seams was constructed. Meanwhile,under the influence of the shaped-charge structure,the crushed zone has an oval-like shape with a small radius in the direction of the shaped-charge jet,while the crack-intensive and main crack-propagation zones have oval-like shapes with a larger radius in the direction of the shaped-charge jet. In addition,field experiments of deep-hole cumulative blasting with linear-shaped charge in coal seams were carried out and the experimental results show that the influence of the cumulative blasting on the increase of the coal-seam-gas volume fraction in each observation hole weakened in a step-wise manner(strong-medium-weak) with increasing distance from the blasting borehole; this is consistent with the partition model of the constructed cumulative blasting,i. e.,the cumulative-blastingaffected area has certain zoning characteristics,and the crushed,crack-intensive,and main crack-propagation zones are the main components of the effective fracture zone.
Deep-hole directional cumulative-blasting cracking technology has unique advantages for improving coal seam permeability. This paper was concerned with the range of the effective fracture zone under cumulative blasting using a linear-shaped charge in a coal seam. Based on the analysis of the mechanism of the directional cumulative-blasting in coal seams,the response characteristics of the coal under the coupled effects of the blasting-induced shock wave,stress wave,detonation gas and the energy-cumulative effect,and the partition characteristics of the crack in the cumulative-blasting-affected area were studied by theoretical analysis; moreover,a numerical analysis model of cumulative blasting was established,and the propagation distribution characteristics and range of coal seam fracture under cumulative blasting were investigated through numerical simulation. The results of the theoretical analysis and simulation show that the cumulative-blasting-affected area can be divided into crushed,crack,and elastic-deformation zones; further,the crack zone can be divided into crack-intensive and main crack-propagation zones according to the type and number of cracks. Additionally,a partition model for the influence of deep-hole cumulative blasting with linear-shaped charge in coal seams was constructed. Meanwhile,under the influence of the shaped-charge structure,the crushed zone has an oval-like shape with a small radius in the direction of the shaped-charge jet,while the crack-intensive and main crack-propagation zones have oval-like shapes with a larger radius in the direction of the shaped-charge jet. In addition,field experiments of deep-hole cumulative blasting with linear-shaped charge in coal seams were carried out and the experimental results show that the influence of the cumulative blasting on the increase of the coal-seam-gas volume fraction in each observation hole weakened in a step-wise manner(strong-medium-weak) with increasing distance from the blasting borehole; this is consistent with the partition model of the constructed cumulative blasting,i. e.,the cumulative-blastingaffected area has certain zoning characteristics,and the crushed,crack-intensive,and main crack-propagation zones are the main components of the effective fracture zone.
引文
[1] Guo D Y,Zhao J C,Zhang C,et al. Mechanism of control hole on coal crack initiation and propagation under deep-hole cumulative blasting in coal seam. Chin J Rock Mech Eng,2018,37(4):919(郭德勇,赵杰超,张超,等.煤层深孔聚能爆破控制孔作用机制研究.岩石力学与工程学报,2018,37(4):919)
[2] Gong M,Liu W B,Wang D S,et al. Controlled blasting technique to improve gas pre-drainage effect in a coal mine. J Univ Sci Technol Beijing,2006,28(3):223(龚敏,刘万波,王德胜,等.提高煤矿瓦斯抽放效果的控制爆破技术.北京科技大学学报,2006,28(3):223)
[3] Guo D Y,Zhao J C,LüP F,et al. Dynamic effects of deep-hole cumulative blasting in coal seam and its application. Chin J Eng,2016,38(12):1681(郭德勇,赵杰超,吕鹏飞,等.煤层深孔聚能爆破动力效应分析与应用.工程科学学报,2016,38(12):1681)
[4] Liu J,Liu Z G,Gao K,et al. Experimental study and application of directional focused energy blasting in deep boreholes. Chin J Rock Mech Eng,2014,33(12):2490(刘健,刘泽功,高魁,等.深孔定向聚能爆破增透机制模拟试验研究及现场应用.岩石力学与工程学报,2014,33(12):2490)
[5] Mu C M,Wang H L,Huang W Y,et al. Increasing permeability mechanism using directional cumulative blasting in coal seams with high concentration of gas and low permeability. Rock Soil Mech,2013,34(9):2496(穆朝民,王海露,黄文尧,等.高瓦斯低透气性煤体定向聚能爆破增透机制.岩土力学,2013,34(9):2496)
[6] Kutter H K,Fairhurst C. On the fracture process in blasting. Int J Rock Mech Min Sci Geomech Abstracts,1971,8(3):181
[7] Chen S H,Wang M Y,Zhao Y T,et al. Time-stress history on interface between cracked and uncracked zones under rock blasting. Chin J Rock Mech Eng,2003,22(11):1784(陈士海,王明洋,赵跃堂,等.岩石爆破破坏界面上的应力时程研究.岩石力学与工程学报,2003,22(11):1784)
[8] Guo D Y,LüP F,Pei H B,et al. Numerical simulation on crack propagation of coal bed deep-hole cumulative blasting. J China Coal Soc,2012,37(2):274(郭德勇,吕鹏飞,裴海波,等.煤层深孔聚能爆破裂隙扩展数值模拟.煤炭学报,2012,37(2):274)
[9] Zong Q. Calculation of radius of cracked zone in rock by blast-induced stress wave. Blasting,1994(2):15(宗琦.岩石内爆炸应力波破裂区半径的计算.爆破,1994(2):15)
[10] Gao J S,Zhang J C. Dynamic analysis of fracturing mechanism of rock under explosion. Met Mine,1989(9):7(高金石,张继春.爆破破岩机理动力分析.金属矿山,1989(9):7)
[11] Dai J. Calculation of radii of the broken and cracked areas in rock by a long charge explosion. J Liaoning Tech Univ Nat Sci Ed,2001,20(2):144(戴俊.柱状装药爆破的岩石压碎圈与裂隙圈计算.辽宁工程技术大学学报(自然科学版),2001,20(2):144)
[12] Esen S,Onederra I,Bilgin H A. Modelling the size of the crushed zone around a blasthole. Int J Rock Mech Min Sci,2003,40(4):485
[13] Far M S,Wang Y. Probabilistic analysis of crushed zone for rock blasting. Comput Geotech,2016,80:290
[14] Zhu Z M,Mohanty B,Xie H P. Numerical investigation of blasting-induced crack initiation and propagation in rocks. Int J Rock Mech Min Sci,2007,44(3):412
[15] Zhu W C,Wei C H,Li S,et al. Numerical modeling on destress blasting in coal seam for enhancing gas drainage. Int J Rock Mech Min Sci,2013,59:179
[16] Yilmaz O,Unlu T. Three dimensional numerical rock damage analysis under blasting load. Tunnelling Underground Space Technol,2013,38:266
[17] Dehghan Banadaki M M,Mohanty B. Numerical simulation of stress wave induced fractures in rock. Int J Impact Eng,2012,40-41:16
[18] Lai X P,Cui F,Cao J T,et al. Extra-thick coal blasting mechanism and numerical simulation of partition failure. J China Coal Soc,2014,39(8):1642(来兴平,崔峰,曹建涛,等.特厚煤体爆破致裂机制及分区破坏的数值模拟.煤炭学报,2014,39(8):1642)
[19] Wang W L. Hole Blasting. Beijing:China Coal Industry Publishing House,1984(王文龙.钻眼爆破.北京:煤炭工业出版社,1984)
[20] Xia X,Li J R,Li H B,et al. Study on damage characteristics of rock mass under blasting load in Ling'ao nuclear power station,Guangdong Province. Chin J Rock Mech Eng,2007,26(12):2510(夏祥,李俊如,李海波,等.广东岭澳核电站爆破开挖岩体损伤特征研究.岩石力学与工程学报,2007,26(12):2510)
[21] Yang Y Q,Gao Q C,Yu M S,et al. Experimental study of mechanism and technology of directed crack blasting. J China Univ Min Technol,1995,5(2):69
[22] Taylor L M,Chen E P,Kuszmaul J S. Microcrack-induced damage accumulation in brittle rock under dynamic loading. Comput Methods Appl Mech Eng,1986,55(3):301
[23] Grady D E,Kipp M E. Continuum modelling of explosive fracture in oil shale. Int J Rock Mech Min Sci Geomech Abstracts,1980,17(3):147
[24] Liu W X. Studies on the mechanism of fracture control blasting for mining rock materials. Explosion Shock Waves,1993,13(2):118(刘文轩.断裂控制爆破开采石材机理的研究.爆炸与冲击,1993,13(2):118)
[25] Chu H B. Theoretical and Experimental Studies on Coal Blasting Action Mechanism[Dissertation]. Jiaozuo:Henan Polytechnic University,2011(褚怀保.煤体爆破作用机理及试验研究[学位论文].焦作:河南理工大学,2011)
[26] Hallquist J O. LS-DYNA Keyword User's Manual(Version 971).Livermore:Livermore Software Technology Corporation,2007
[2] Gong M,Liu W B,Wang D S,et al. Controlled blasting technique to improve gas pre-drainage effect in a coal mine. J Univ Sci Technol Beijing,2006,28(3):223(龚敏,刘万波,王德胜,等.提高煤矿瓦斯抽放效果的控制爆破技术.北京科技大学学报,2006,28(3):223)
[3] Guo D Y,Zhao J C,LüP F,et al. Dynamic effects of deep-hole cumulative blasting in coal seam and its application. Chin J Eng,2016,38(12):1681(郭德勇,赵杰超,吕鹏飞,等.煤层深孔聚能爆破动力效应分析与应用.工程科学学报,2016,38(12):1681)
[4] Liu J,Liu Z G,Gao K,et al. Experimental study and application of directional focused energy blasting in deep boreholes. Chin J Rock Mech Eng,2014,33(12):2490(刘健,刘泽功,高魁,等.深孔定向聚能爆破增透机制模拟试验研究及现场应用.岩石力学与工程学报,2014,33(12):2490)
[5] Mu C M,Wang H L,Huang W Y,et al. Increasing permeability mechanism using directional cumulative blasting in coal seams with high concentration of gas and low permeability. Rock Soil Mech,2013,34(9):2496(穆朝民,王海露,黄文尧,等.高瓦斯低透气性煤体定向聚能爆破增透机制.岩土力学,2013,34(9):2496)
[6] Kutter H K,Fairhurst C. On the fracture process in blasting. Int J Rock Mech Min Sci Geomech Abstracts,1971,8(3):181
[7] Chen S H,Wang M Y,Zhao Y T,et al. Time-stress history on interface between cracked and uncracked zones under rock blasting. Chin J Rock Mech Eng,2003,22(11):1784(陈士海,王明洋,赵跃堂,等.岩石爆破破坏界面上的应力时程研究.岩石力学与工程学报,2003,22(11):1784)
[8] Guo D Y,LüP F,Pei H B,et al. Numerical simulation on crack propagation of coal bed deep-hole cumulative blasting. J China Coal Soc,2012,37(2):274(郭德勇,吕鹏飞,裴海波,等.煤层深孔聚能爆破裂隙扩展数值模拟.煤炭学报,2012,37(2):274)
[9] Zong Q. Calculation of radius of cracked zone in rock by blast-induced stress wave. Blasting,1994(2):15(宗琦.岩石内爆炸应力波破裂区半径的计算.爆破,1994(2):15)
[10] Gao J S,Zhang J C. Dynamic analysis of fracturing mechanism of rock under explosion. Met Mine,1989(9):7(高金石,张继春.爆破破岩机理动力分析.金属矿山,1989(9):7)
[11] Dai J. Calculation of radii of the broken and cracked areas in rock by a long charge explosion. J Liaoning Tech Univ Nat Sci Ed,2001,20(2):144(戴俊.柱状装药爆破的岩石压碎圈与裂隙圈计算.辽宁工程技术大学学报(自然科学版),2001,20(2):144)
[12] Esen S,Onederra I,Bilgin H A. Modelling the size of the crushed zone around a blasthole. Int J Rock Mech Min Sci,2003,40(4):485
[13] Far M S,Wang Y. Probabilistic analysis of crushed zone for rock blasting. Comput Geotech,2016,80:290
[14] Zhu Z M,Mohanty B,Xie H P. Numerical investigation of blasting-induced crack initiation and propagation in rocks. Int J Rock Mech Min Sci,2007,44(3):412
[15] Zhu W C,Wei C H,Li S,et al. Numerical modeling on destress blasting in coal seam for enhancing gas drainage. Int J Rock Mech Min Sci,2013,59:179
[16] Yilmaz O,Unlu T. Three dimensional numerical rock damage analysis under blasting load. Tunnelling Underground Space Technol,2013,38:266
[17] Dehghan Banadaki M M,Mohanty B. Numerical simulation of stress wave induced fractures in rock. Int J Impact Eng,2012,40-41:16
[18] Lai X P,Cui F,Cao J T,et al. Extra-thick coal blasting mechanism and numerical simulation of partition failure. J China Coal Soc,2014,39(8):1642(来兴平,崔峰,曹建涛,等.特厚煤体爆破致裂机制及分区破坏的数值模拟.煤炭学报,2014,39(8):1642)
[19] Wang W L. Hole Blasting. Beijing:China Coal Industry Publishing House,1984(王文龙.钻眼爆破.北京:煤炭工业出版社,1984)
[20] Xia X,Li J R,Li H B,et al. Study on damage characteristics of rock mass under blasting load in Ling'ao nuclear power station,Guangdong Province. Chin J Rock Mech Eng,2007,26(12):2510(夏祥,李俊如,李海波,等.广东岭澳核电站爆破开挖岩体损伤特征研究.岩石力学与工程学报,2007,26(12):2510)
[21] Yang Y Q,Gao Q C,Yu M S,et al. Experimental study of mechanism and technology of directed crack blasting. J China Univ Min Technol,1995,5(2):69
[22] Taylor L M,Chen E P,Kuszmaul J S. Microcrack-induced damage accumulation in brittle rock under dynamic loading. Comput Methods Appl Mech Eng,1986,55(3):301
[23] Grady D E,Kipp M E. Continuum modelling of explosive fracture in oil shale. Int J Rock Mech Min Sci Geomech Abstracts,1980,17(3):147
[24] Liu W X. Studies on the mechanism of fracture control blasting for mining rock materials. Explosion Shock Waves,1993,13(2):118(刘文轩.断裂控制爆破开采石材机理的研究.爆炸与冲击,1993,13(2):118)
[25] Chu H B. Theoretical and Experimental Studies on Coal Blasting Action Mechanism[Dissertation]. Jiaozuo:Henan Polytechnic University,2011(褚怀保.煤体爆破作用机理及试验研究[学位论文].焦作:河南理工大学,2011)
[26] Hallquist J O. LS-DYNA Keyword User's Manual(Version 971).Livermore:Livermore Software Technology Corporation,2007