深部孤岛工作面区段煤柱冲击地压的试验研究
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摘要
以冲击启动理论为基础,结合覆岩空间结构思想,采用相似模拟试验方法,研究了孤岛工作面上覆岩层空间结构特点及采动围岩应力场的分布、变化规律,进一步探讨了孤岛工作面区段煤柱冲击地压发生机理。结果表明,两侧充分开采的孤岛工作面上覆岩层呈"C"型覆岩空间结构,工作面承受上部岩层及两侧采空区上覆岩层转移过来的部分岩层重量,在工作面两侧形成应力集中区域,导致采动围岩应力场达到极限平衡状态,该集中应力可视为采动围岩近场极限平衡系统的静载荷。孤岛工作面开采过程中"C"型覆岩空间结构逐渐演化形成"W"型空间结构,极限平衡系统静载荷发生转移和改变,最终由上下区段煤柱全部承担上覆岩层重量,系统载荷增至最大,处于临界失稳状态。"W"型覆岩空间结构大面积失稳,为系统提供了外动载荷,系统在动载荷的扰动下突破平衡极限,从而发生区段煤柱冲击。最后,基于孤岛工作面应力分布规律确定了区段煤柱的合理尺寸。
The paper is inclined to present its experimental study on the rockburst of the coal pillar section in the deep isolated workface in coal mining practice based on the rockburst initiating theory and the idea of overlaying strata of the spatial structure.For the study purpose,we have made a dynamic simulation test method by studying the spatial structure characteristic features of the overlaying strata and the distributive rule of the surrounding rock stress in the isolated mining workface so as to be able to monitor the coal stress in the process of mining by using a BW-0. 5 micro-stress detector and a YJZ-2 intelligent digital strain testing system. In proceeding with our study,we have made an examination of the rockburst mechanism of the coal pillar section in such workface ulteriorly from a distance far away through analyzing the spatial and temporal evolutionary regularity of the surrounding rock stress. The results of our experimental studies show that,the spatial structure of the overlaying strata tends to be in a letter"C"form when both of the isolated workface sides have been almost wholly mined out and resulted in a goaf,which has to be supported and propped merely by the weight of the upper strata and some of the metastasized overburdened rock of the goaf. In such a case,it seems to be natural for the stress field of the surrounding rocks to be focused on the two sides of the workface.What is more,the space structure in the letter "C "form may gradually evolve into a letter "W"one in the process of mining.Thus,the said isolated section and the limit equilibrium system of the static load shift would gradually turn to be a section of the coal pillar and take over all the weight of the overburdened rock. It is in this manner that the static load shift may increase to the maximum limit,with the system turning to be in a critical state of instability. Furthermore,the obvious instability of "W " space structure would lead to the transfer of the original static balance and the breakdown of the original balanced limit,thus leading to the rockburst of the coal pillar. Besides,we have also made an analysis of the size of the coal pillar section based on the isolated face stress distribution regularity,arriving at a conclusion that the reasonable size of the section coal pillar should be made between0-5. 0 m,which can help to eliminate the likely rockburst risk effectively.
The paper is inclined to present its experimental study on the rockburst of the coal pillar section in the deep isolated workface in coal mining practice based on the rockburst initiating theory and the idea of overlaying strata of the spatial structure.For the study purpose,we have made a dynamic simulation test method by studying the spatial structure characteristic features of the overlaying strata and the distributive rule of the surrounding rock stress in the isolated mining workface so as to be able to monitor the coal stress in the process of mining by using a BW-0. 5 micro-stress detector and a YJZ-2 intelligent digital strain testing system. In proceeding with our study,we have made an examination of the rockburst mechanism of the coal pillar section in such workface ulteriorly from a distance far away through analyzing the spatial and temporal evolutionary regularity of the surrounding rock stress. The results of our experimental studies show that,the spatial structure of the overlaying strata tends to be in a letter"C"form when both of the isolated workface sides have been almost wholly mined out and resulted in a goaf,which has to be supported and propped merely by the weight of the upper strata and some of the metastasized overburdened rock of the goaf. In such a case,it seems to be natural for the stress field of the surrounding rocks to be focused on the two sides of the workface.What is more,the space structure in the letter "C "form may gradually evolve into a letter "W"one in the process of mining.Thus,the said isolated section and the limit equilibrium system of the static load shift would gradually turn to be a section of the coal pillar and take over all the weight of the overburdened rock. It is in this manner that the static load shift may increase to the maximum limit,with the system turning to be in a critical state of instability. Furthermore,the obvious instability of "W " space structure would lead to the transfer of the original static balance and the breakdown of the original balanced limit,thus leading to the rockburst of the coal pillar. Besides,we have also made an analysis of the size of the coal pillar section based on the isolated face stress distribution regularity,arriving at a conclusion that the reasonable size of the section coal pillar should be made between0-5. 0 m,which can help to eliminate the likely rockburst risk effectively.
引文
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[10]WANG Cunwen(王存文),JIANG Fuxing(姜福兴),SUN Qingguo(孙庆国),et al.The forecasting method of rock-burst and the application based on overling multi-strata spatial structure theory[J].Journal of China Coal Society(煤炭学报),2009,34(2):150-155.
[11]JIANG Fuxing(姜福兴),XUN Luo,YANG Shuhua(杨淑华).Study on micro seismic monitoring for spatial and mining pressure field in structure of overlying strata long wall face[J].Chinese Journal of Ceotechnical Engineering(岩土工程学报),2003,25(1):23-24.
[12]JIANG Fuxing(姜福兴).View point of spatial structures of overlying strata and its application in coal mine[J].Journal of Mining&Safely Engineering(采矿与安全工程学报),2006,23(2):30-33.
[13]PAN Junfeng(潘俊锋),NING Yu(宁宇),MAO Debing(毛德兵),et al.Theory of rock burst start-up during coal mining[J].Chinese Journal of Rock Mechanics and Engineering(岩石力学与工程学报),2012,31(3):586-596.
[14]PAN Junfeng(潘俊锋),QIN Zihan(秦子晗),FENG Meihua(冯美华),et al.Start-up principle of concentrated static load type rockburst in short wall work face under magmatic rocks roof[J].Rock and Soil Mechanics(岩土力学),2015,36(9):2632-2637.
[15]QI Qingxin(齐庆新),LEI Yi(雷毅),LI Hongyan(李宏艳),et al.Theory and application of prevention of rock burst by break-tip blast in deep hole[J].Chinese Journal of Rock Mechanics and Engineering(岩石力学与工程学报),2007,26(Sl):3522-3527.
[16]LIU Xiaofei(刘晓斐),WANG Enyuan(王恩元),ZHAO Enlai(赵恩来),et al.Study on multi-prediction of rock burst in the mining of gob-surrounded coal face and demonstration[J].Journal of Mining&Safely Engineering(采矿与安全工程学报),2010,27(2):215-218.
[17]GUY R,KENT M,RUSSELL F.An assessment of coal pillar system stability criteria based on a mechanistic evaluation of the interaction between coal pillars and the overburden[J].International Journal of Mining Science and Technology,2017,27(1):9-15.
[2]JIANG Yaodong(姜耀东),PAN Yishan(潘一山),JIANG Fuxing(姜福兴),et al.State of the art review on mechanism and prevention of coal bumps in China[J].Journal of China Coal Society(煤炭学报),2014,39(2):205-213.
[3]YOUNG R P,COLLINS D S.Seismic studies of rock fracture at the Underground Research Laboratory,Canada[J].International Journal of Rock Mechanics and Mining Sciences,2001,38(6):787-799.
[4]CHENG Yunhai(成云海),MA Yankun(马衍坤),HU Zhaofeng(胡兆锋),et al.Mechanism and key technologies of preventing rock burst by outward staggered entries arrangement in fully-mechanized caving mining face[J].Journal of China Coal Society(煤炭学报),2016,41(3):564-570.
[5]PAN Yishan(潘一山),GENG Lin(耿琳),LI Zhonghua(李忠华).Research on evaluation indices for impact tendency and danger of coal seam[J].Journal of China Coal Society(煤炭学报),2010,35(12):1975-1977.
[6]JIANG Yaodong(姜耀东),ZHAO Yixin(赵毅鑫),HE Manchao(何满潮),et al.Investigation on mechanicism of coal mnie bumps based on mesoscopic experiments[J].Chinese Journal of Rock Mechanics and Engineering(岩石力学与工程学报),2007,26(5):901-907.
[7]PAN Yishan(潘一山).Study on rock burst initiation and failure propagation(冲击地压发生和破坏过程研究)[D].Beijing:Tsinghua University,1999.
[8]LI Dianping(李佃平),DOU Linming(窦林名),MU Zonglong(牟宗龙),et al.The anti-arc overlying strata structure induced mechanism and control of isolated corner coal pillar working face[J].Journal of China Coal Society(煤炭学报),2012,37(5):719-724.
[9]DOU Linming(窦林名),HE Ye(何烨),ZHANG Weidong(张卫东),et al.Hazards of rock burst in island coal face and its control[J].Chinese Journal of Rock Mechanics and Engineering(岩石力学与工程学报),2003,22(11):1866-1869.
[10]WANG Cunwen(王存文),JIANG Fuxing(姜福兴),SUN Qingguo(孙庆国),et al.The forecasting method of rock-burst and the application based on overling multi-strata spatial structure theory[J].Journal of China Coal Society(煤炭学报),2009,34(2):150-155.
[11]JIANG Fuxing(姜福兴),XUN Luo,YANG Shuhua(杨淑华).Study on micro seismic monitoring for spatial and mining pressure field in structure of overlying strata long wall face[J].Chinese Journal of Ceotechnical Engineering(岩土工程学报),2003,25(1):23-24.
[12]JIANG Fuxing(姜福兴).View point of spatial structures of overlying strata and its application in coal mine[J].Journal of Mining&Safely Engineering(采矿与安全工程学报),2006,23(2):30-33.
[13]PAN Junfeng(潘俊锋),NING Yu(宁宇),MAO Debing(毛德兵),et al.Theory of rock burst start-up during coal mining[J].Chinese Journal of Rock Mechanics and Engineering(岩石力学与工程学报),2012,31(3):586-596.
[14]PAN Junfeng(潘俊锋),QIN Zihan(秦子晗),FENG Meihua(冯美华),et al.Start-up principle of concentrated static load type rockburst in short wall work face under magmatic rocks roof[J].Rock and Soil Mechanics(岩土力学),2015,36(9):2632-2637.
[15]QI Qingxin(齐庆新),LEI Yi(雷毅),LI Hongyan(李宏艳),et al.Theory and application of prevention of rock burst by break-tip blast in deep hole[J].Chinese Journal of Rock Mechanics and Engineering(岩石力学与工程学报),2007,26(Sl):3522-3527.
[16]LIU Xiaofei(刘晓斐),WANG Enyuan(王恩元),ZHAO Enlai(赵恩来),et al.Study on multi-prediction of rock burst in the mining of gob-surrounded coal face and demonstration[J].Journal of Mining&Safely Engineering(采矿与安全工程学报),2010,27(2):215-218.
[17]GUY R,KENT M,RUSSELL F.An assessment of coal pillar system stability criteria based on a mechanistic evaluation of the interaction between coal pillars and the overburden[J].International Journal of Mining Science and Technology,2017,27(1):9-15.