爆破载荷作用下煤厚变异区损伤破坏特征实验研究
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摘要
针对地质构造区域爆破施工容易诱发煤与瓦斯突出的现实情况,建立煤岩组合弹性力学模型、根据爆炸应力波在煤岩介质中的传播与作用规律,分析了煤层变厚时原岩应力的分布特征、爆炸应力波在构造煤岩体中的传播过程,并结合相似模拟实验与数值模拟研究了爆破载荷作用下煤厚变异区的损伤破坏特征。理论分析表明,薄煤层区域承受的原岩应力高于厚煤层,且应力变化梯度随煤厚减小率的增大而增大,爆炸应力波由岩体传播至构造煤体时会发生波的透射和反射现象,反射形成的拉伸波将加剧煤岩交界面岩体侧的损伤程度;爆破模拟实验中采集得到的应力曲线,煤厚变异区岩体处的测点存在着2次较大的拉应力峰值,应力波在该处相互作用形成了叠加破坏区,破坏区同时又引导其余方向的爆生裂纹向其延伸汇集,导致岩体严重破坏。数值模拟验证了爆炸应力波在煤岩交界面上的透射和反射现象,应力云图表明应力波在煤厚渐变区的叠加作用最明显且延续时间长。研究成果对于揭示爆破扰动煤厚变异区诱发煤与瓦斯突出的机制有重要指导意义。
Aiming at the fact that coal and gas outbursts are easily induced in regional blasting construction of geological structures, an elastic mechanical model of coal and rock combination was established. Based on propagation and action laws of blast stress waves in coal and rock medium, distribution features of the original rock stress during coal seam thickening and propagation process of explosion stress waves in tectonic coal rock mass were analyzed. Using similar analog tests combined with numerical simulations, the damage and failure characteristics of coal thickness variation zones under blast loading were studied. The results of tests and simulations showed that the original rock stress withstood by thin coal seam is higher than that withstood by thick coal seam, and the stress change gradient increases with increase in coal thickness reduction rate; when blast stress waves propagate from rock body to tectonic coal body, wave transmission and reflection phenomena occur; the reflection-induced tensile wave aggravates the damage level of rock body side of coal-rock interface; stress curves acquired from blast analog tests indicate, the stress waves mutually act to form a superposed failure zone at the rock body of the coal thickness variation area, the failure zone makes blast-induced cracks in other directions extend to it and gather to cause serious failures of the rock body, the tensile stress in the failure zone has 2 larger peak values; the numerical simulations verify transmission and reflection phenomena of blast stress waves at the interface of coal and rock; the stress cloud diagram indicates, the superposition action of stress waves in the coal thickness transition region is the most obvious and lasts long time. The study results provided a meaningful guide for revealing the mechanism of blasts to disturb a coal thickness variation area and induce coal and gas outbursts.
Aiming at the fact that coal and gas outbursts are easily induced in regional blasting construction of geological structures, an elastic mechanical model of coal and rock combination was established. Based on propagation and action laws of blast stress waves in coal and rock medium, distribution features of the original rock stress during coal seam thickening and propagation process of explosion stress waves in tectonic coal rock mass were analyzed. Using similar analog tests combined with numerical simulations, the damage and failure characteristics of coal thickness variation zones under blast loading were studied. The results of tests and simulations showed that the original rock stress withstood by thin coal seam is higher than that withstood by thick coal seam, and the stress change gradient increases with increase in coal thickness reduction rate; when blast stress waves propagate from rock body to tectonic coal body, wave transmission and reflection phenomena occur; the reflection-induced tensile wave aggravates the damage level of rock body side of coal-rock interface; stress curves acquired from blast analog tests indicate, the stress waves mutually act to form a superposed failure zone at the rock body of the coal thickness variation area, the failure zone makes blast-induced cracks in other directions extend to it and gather to cause serious failures of the rock body, the tensile stress in the failure zone has 2 larger peak values; the numerical simulations verify transmission and reflection phenomena of blast stress waves at the interface of coal and rock; the stress cloud diagram indicates, the superposition action of stress waves in the coal thickness transition region is the most obvious and lasts long time. The study results provided a meaningful guide for revealing the mechanism of blasts to disturb a coal thickness variation area and induce coal and gas outbursts.
引文
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[14] 国家安全生产监督管理总局和国家煤矿安全监察局网站事故查调查处理[EB /OL].http://www.chinasafety.gov.cn/newpage/zwgk/tdsgdccl/zwgk_tdsgdccl_lm.htm,2015-08-15.
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[17] 穆朝民,齐娟.爆炸荷载作用下煤体裂纹扩展机理模型实验研究[J].振动与冲击,2012,31(13):58-61.MU Chaomin,QI Juan.Model investigation on cracks propagation in coal under blast loading[J].Journal of Vibration and Shock,2012,31(13):58-61.
[18] 夏彬伟,刘承伟,卢义玉,等.缝槽水压爆破导向裂缝扩展实验研究[J].煤炭学报,2016,41(2):432-438.XIA Binwei,LIU Chengwei,LU Yiyu,et al.Experimental study of propagation of directional fracture with slotting hydraulic blasting[J].Journal of China Coal Society,2016,41(2):432-438.
[2] 郭德勇,商登莹,吕鹏飞,等.深孔聚能爆破坚硬顶板弱化试验研究[J].煤炭学报,2013,38(7):1149-1153.GUO Deyong,SHANG Dengying,Lü Pengfei,et al.Experimental research of deep-hole cumulative blasting in hard roof weakening[J].Journal of China Coal Society,2013,38(7):1149-1153.
[3] 刘健,刘泽功,高魁.深孔爆破在综放开采坚硬顶煤预先弱化和瓦斯抽采中的应用[J].岩石力学与工程学报,2014,33(增刊1):3361-3367.LIU Jian,LIU Zegong,GAO Kui,et al.Application of deep borehole blasting to top-coal pre-weakening and gas extraction in fully mechanized caving[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(Sup1):3361-3367.
[4] 李廷春,刘洪强.煤矿下山巷道爆破掘进技术试验研究[J].岩土力学,2012,33(1):35-47.LI Tingchun,LIU Hongqiang.Experimental study of blasting technology of dip roadway excavation in coal mine[J].Rock and Soil Mechanics,2012,33(1):35-47.
[5] 于不凡.煤和瓦斯突出机理[M].北京:煤炭工业出版社,1985.
[6] 孙重旭,孔凡正.炮采炮掘工作面煤与瓦斯突出的特点与防治[J].煤炭工程师,1998(3):19-22.SUN Chongxu,KONG Fanzheng.Characteristics of gas and coal out-burst at coal heading faces by blasting and its prevention and control[J].Journal of China Coal Engineer,1998(3):19-22.
[7] 常未斌,樊少武,张浪,等.基于爆炸应力波和构造煤带孕育煤与瓦斯突出危险状态的模型[J].煤炭学报,2014,39(11):2226-2231.CHANG Weibin,FAN Shaowu,ZHANG Lang,et al.A model based on explosive stress wave and tectonic coal zone which gestate dangerous state of coal and gas outburst[J].Journal of China Coal Society,2014,39(11):2226-2231.
[8] 李伟,连昌宝.淮北煤田煤与瓦斯突出地质因素分析与防治[J].煤炭科学技术,2007,35(1):19-22.LI Wei,LIAN Changbao.Geological factors analysis of coal and gas outburst in Huaibei Coal Field[J].Coal Science and Technology,2007,35(1):19-22.
[9] 魏建平,张文勇,潘辉,等.鹤壁矿区煤与瓦斯突出特征及影响因素分析[J].煤炭工程,2007(4):60-62.WEI Jianping,ZHANG Wenyong,PAN Hui,et al.Analysis on coal and gas outburst features and influence factors in Hebi Mining Area[J].Coal Engineering,2007(4):60-62.
[10] CAO Y X,HE D D,DAVID C,et al.Coal and gasoutbursts in footwalls of reverse faults[J].International Journal of Coal Geology,2001,48:47-63.
[11] 邵强,王恩元.构造煤分布规律对煤与瓦斯突出的控制[J].煤炭学报,2010,35(2):250-254.SHAO Qiang,WANG Enyuan.Control to coal and gas outburst of tec-tonic coal distribution[J].Journal of China Coal Society,2010,35(2):250-254.
[12] 韩军,张宏伟,霍丙杰.向斜构造煤与瓦斯突出机理探讨[J].煤炭学报,2008,38(7):908-913.HAN Jun,ZHANG Hongwei,HUO Bingjie.Discussion of coal and gas outburst mechanism of syncline[J].Journal of China Coal Society,2008,38(7):908-913.
[13] 郭德勇,韩德馨,张建国.平顶山矿区构造煤分布规律及成因研究[J].煤炭学报,2002,27(3):249-253.GUO Deyong,HAN Dexin,ZHANG Jianguo.Research on the occurrence and distribution of structural coal in Pingdingshan Coal District[J].Journal of China Coal Society,2002,27(3):249-253.
[14] 国家安全生产监督管理总局和国家煤矿安全监察局网站事故查调查处理[EB /OL].http://www.chinasafety.gov.cn/newpage/zwgk/tdsgdccl/zwgk_tdsgdccl_lm.htm,2015-08-15.
[15] 赵同彬,郭伟耀,谭云亮,等.煤厚变异区开采冲击地压发生的力学机制[J].煤炭学报,2016,41 (7):1659-1666.ZHAO Tongbin,GUO Weiyao,TAN Yunliang,et al.Mechanics mechanism of rock burst caused by mining in the variable region of coal thickness[J].Journal of China Coal Society,2016,41 (7):1659-1666.
[16] 刘健,刘泽功,高魁,.深孔爆破在综放开采坚硬顶煤预先弱化和瓦斯抽采中的应用[J].岩石力学与工程学报,2014,33(增刊1):3361-3367.LIU Jian,LIU Zegong,GAO Kui,et al.Application of deep borehole blasting to top-coal pre-weakening and gas extraction in fully mechanized caving[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(Sup1):3361-3367.
[17] 穆朝民,齐娟.爆炸荷载作用下煤体裂纹扩展机理模型实验研究[J].振动与冲击,2012,31(13):58-61.MU Chaomin,QI Juan.Model investigation on cracks propagation in coal under blast loading[J].Journal of Vibration and Shock,2012,31(13):58-61.
[18] 夏彬伟,刘承伟,卢义玉,等.缝槽水压爆破导向裂缝扩展实验研究[J].煤炭学报,2016,41(2):432-438.XIA Binwei,LIU Chengwei,LU Yiyu,et al.Experimental study of propagation of directional fracture with slotting hydraulic blasting[J].Journal of China Coal Society,2016,41(2):432-438.