非对称开采条件下工作面“多向应力”变化特征研究
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摘要
在非对称开采条件下,工作面受上覆岩层自重应力、超前支承应力、采空区侧向支承应力和回风巷煤柱应力等"多向应力"叠加影响,使得工作面应力呈"非对称"性。为研究非对称开采条件下工作面"多向应力"变化特征,基于微震监测、应力在线监测和理论计算,对母杜柴登煤矿30202工作面回采过程中所形成的非对称开采条件下的应力变化进行分析;并基于工作面所受应力条件和围岩体结构条件,分析了"多向应力"叠加显现机理。结果表明:30202工作面回采期间,煤柱支承应力沿走向分为应力升高区、应力明显降低区、应力缓慢降低区和应力稳定区,其应力峰值主要集中在工作面前方40 m左右,应力集中系数平均为1. 61;在非对称开采阶段,在走向方向工作面超前支承应力影响范围较回采初期增加了100 m左右;在不考虑垂直应力影响的情况下,相邻工作面采空区的侧向应力对30202工作面倾向方向的影响范围为44 m,应力最大值为56. 1 MPa。在"多向应力"耦合作用下工作面在回采过程中产生能量集聚,并在采动扰动下发生能量释放,满足了大能量事件发生的基本应力条件;同时在扰动条件下采空区发生高位顶板错动,以及围岩支护薄弱为大能量事件的发生提供了围岩结构条件。研究结果可为工作面非对称开采条件下采场矿压显现规律研究、顶板控制和巷道支护设计提供指导。
The present article is inclined to analyze the stress change of 30202 working face in Mudu-Chaideng Coal Mine under the asymmetric mining conditions in hoping to identify and determine the impact of the variation of the characteristic features of the "multiplisided stress" in the working face under the asymmetric mining conditions. The study of the article is based on the condition of the microseismic monitoring,on-line stress monitoring plus the corresponding theoretical calculation. As is well known,under the condition of the asymmetric mining,the working face of a coal mine ought to be influenced by the "multiplisided stress" ,such as the gravity stress of the overlying strata,the advancing supporting stress,the lateral supporting stress in the goaf as well as the pillar stress. Briefly speaking,the stress of the working face is endowed with mysterious "asymmetrical" features. Therefore,our analysis has to be done in accordance with the stress condition and the surrounding rock mass structure of the working face,in addition to the analysis of the manifestation mechanism of "multiplisided stress " . The results of our analysis indicate that,in the process of the coal face mining,the supporting stresses of the coal pillar in the direction of dip can be divided into 4 kinds of area category,that is,the stress-increasing area,the stress-decreasing area,the stress slowly-decreasing-area and the stress-stabilizing-area. Of all the aforementioned kinds of stress,the position of the supreme,or the socalled peak stress,should be situated at about 40 m ahead of the working face,with its average stress concentration factor being about 1. 61. Seeing the above-mentioned features,the impact range of the advancing support stress should be endowed with the following particular sorts of features,that is,the strike direction feature of the working face during the stage of the asymmetric mining,which can be expected to increase about 100 m as compared with that of the symmetrical mining. Thus,with no account of the impact of the gravity stress,the impact range of the lateral stress in the goaf of the working face should be as long as 44 m from the goaf to the solid coal,with its maximum value of stress being at about 56. 1 MPa. However,under the coupling of "multiplisided stress," the working face ought to produce a sum of energy accumulation in the mining process,together with the energy release influence under the disturbed action to satisfy the basic stress conditions in case for the serious energy events to come about. At the same time,if the dislocation of high roof in the goaf under consideration to come about under the disturbance condition,and if the surrounding rock support remains weak,it would be of great need to predict or make ready to prevent from the surrounding rock structure collapse or breakdown. Thus,it can be said the research results should be qualified enough to provide significant guidance to the study of the regularity of the stope pressure behaviours under the asymmetric mining conditions,the roof control and roadways support.
The present article is inclined to analyze the stress change of 30202 working face in Mudu-Chaideng Coal Mine under the asymmetric mining conditions in hoping to identify and determine the impact of the variation of the characteristic features of the "multiplisided stress" in the working face under the asymmetric mining conditions. The study of the article is based on the condition of the microseismic monitoring,on-line stress monitoring plus the corresponding theoretical calculation. As is well known,under the condition of the asymmetric mining,the working face of a coal mine ought to be influenced by the "multiplisided stress" ,such as the gravity stress of the overlying strata,the advancing supporting stress,the lateral supporting stress in the goaf as well as the pillar stress. Briefly speaking,the stress of the working face is endowed with mysterious "asymmetrical" features. Therefore,our analysis has to be done in accordance with the stress condition and the surrounding rock mass structure of the working face,in addition to the analysis of the manifestation mechanism of "multiplisided stress " . The results of our analysis indicate that,in the process of the coal face mining,the supporting stresses of the coal pillar in the direction of dip can be divided into 4 kinds of area category,that is,the stress-increasing area,the stress-decreasing area,the stress slowly-decreasing-area and the stress-stabilizing-area. Of all the aforementioned kinds of stress,the position of the supreme,or the socalled peak stress,should be situated at about 40 m ahead of the working face,with its average stress concentration factor being about 1. 61. Seeing the above-mentioned features,the impact range of the advancing support stress should be endowed with the following particular sorts of features,that is,the strike direction feature of the working face during the stage of the asymmetric mining,which can be expected to increase about 100 m as compared with that of the symmetrical mining. Thus,with no account of the impact of the gravity stress,the impact range of the lateral stress in the goaf of the working face should be as long as 44 m from the goaf to the solid coal,with its maximum value of stress being at about 56. 1 MPa. However,under the coupling of "multiplisided stress," the working face ought to produce a sum of energy accumulation in the mining process,together with the energy release influence under the disturbed action to satisfy the basic stress conditions in case for the serious energy events to come about. At the same time,if the dislocation of high roof in the goaf under consideration to come about under the disturbance condition,and if the surrounding rock support remains weak,it would be of great need to predict or make ready to prevent from the surrounding rock structure collapse or breakdown. Thus,it can be said the research results should be qualified enough to provide significant guidance to the study of the regularity of the stope pressure behaviours under the asymmetric mining conditions,the roof control and roadways support.
引文
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[11] XIA Yongxue(夏永学),LAN Hang(蓝航),MAO Debing(毛德兵),et al. Study of the lead abutment pressure distribution base on micro-seismic monitoring[J].Journal of China University of Mining&Technology(中国矿业大学学报),2012,40(6):868-873.
[12] LIU Jinhai(刘金海),JIANG Fuxing(姜福兴),WANG Naiguo(王乃国),et al. Survey on abutment pressure distribution of fully mechanized caving face in extra-thick coal seam of deep shaft[J]. Journal of China Coal Society(煤炭学报),2011,36(S1):18-22.
[13] LIU Xiaofei(刘晓斐),WANG Enyuan(王恩元),HE Xueqiu(何学秋),et al. Electromagnetic radiation laws of the stress distribution in working face[J]. Journal of China Coal Society(煤炭学报),2007,32(10):1019-1022.
[14] LIU Jie(刘杰),WANG Enyuan(王恩元),ZHAO Enlai(赵恩来),et al. Distribution and variation of mining-induced stress field in deep workface[J]. Journal of Mining&Safety Engineering(采矿与安全工程学报),2014,31(1):60-65.
[15] JIANG Fuxing(姜福兴),LIU Yi(刘懿),ZHANG Yichao(张益超),et al. A three-zone structure loading model of overlying strata and its application on rockburst prevention[J]. Chinese Journal of Rock Mechanics and Engineering(岩石力学与工程学报),2016,35(12):2398-2408.
[16] JIANG Fuxing(姜福兴),LIU Yi(刘懿),YANG Weili(杨伟利),et al. Relationship between rock burst and the three zone structure loading model in Yuncheng coal mine[J]. Journal of Mining&Safety Engineering(采矿与安全工程学报),2017,34(3):405-410.
[17] CUI Tiejun(崔铁军),LI Shasha(李莎莎),WANG Laigui(王来贵). On the mesoscopic process rock burst based on the dynamic theory[J]. Journal of Safety and Environment(安全与环境学报),2018,18(2):474-480.
[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] XU Xuefeng(徐学锋),ZHANG Yinliang(张银亮).Causes of blasting induced rock pressure and spectral analysis of microseismic signals[J]. Safety in Coal Mines(煤矿安全),2010,41(9):123-125.
[4] SZWEDZICKI T. The effect of mining geometry on stability of rock mass around underground excavations[J]. Mineral Resources Engineering,2000,9(2):265-278.
[5] XIE Guangxiang(谢广祥),YANG Ke(杨科),GHANG Jucai(常聚才). Analysis on site measurement of support pressure distribution law for seam of fully mechanized longwall top coal caving mining[J]. Coal Science and Technology(煤炭科学技术),2006,34(3):1-3.
[6] XIE Guangxiang(谢广祥),YANG Ke(杨科),CHANG Jucai(常聚才). Study on distribution characteristics of3D stress and thickness effects of coal-seam in unsymmetrical disposal and fully-mechanized top-coal caving[J].Chinese Journal of Rock Mechanics and Engineering(岩石力学与工程学报),2007,26(4):775-779.
[7] JIANG Fuxing(姜福兴),YANG Shuhua(杨淑华),CHENG Yunhai(成云海),et al. A study on microseismic monitoring of rock burst in coal mine[J]. Chinese Journal of Geophysics(地球物理学报),2006,49(5):1511-1516.
[8] JIANG Fuxing(姜福兴),YANG Shuhua(杨淑华),XUN Luo. Spatial fracturing progresses of surrounding rock masses in longwall face monitored by microseismic monitoring techniques[J]. Journal of China Coal Society(煤炭学报),2003,28(4):357-360.
[9] LIU Changyou(刘长友),HUANG Bingxiang(黄炳香),MENG Xiangjun(孟祥军),et al. Research on abutment pressure distribution law of overlength isolated fully-mechanized top coal caving face[J]. Chinese Journal of Rock Mechanics and Engineering(岩石力学与工程学报),2007,26(S1):2761-2766.
[10] XIA Yongxue(夏永学),PAN Junfeng(潘俊锋),WANG Yuanjie(王元杰),et al. Study of rule of surrounding rock failure and stress distribution based on high-precision microseismic monitoring[J]. Journal of China Coal Society(煤炭学报),2011,36(2):239-243.
[11] XIA Yongxue(夏永学),LAN Hang(蓝航),MAO Debing(毛德兵),et al. Study of the lead abutment pressure distribution base on micro-seismic monitoring[J].Journal of China University of Mining&Technology(中国矿业大学学报),2012,40(6):868-873.
[12] LIU Jinhai(刘金海),JIANG Fuxing(姜福兴),WANG Naiguo(王乃国),et al. Survey on abutment pressure distribution of fully mechanized caving face in extra-thick coal seam of deep shaft[J]. Journal of China Coal Society(煤炭学报),2011,36(S1):18-22.
[13] LIU Xiaofei(刘晓斐),WANG Enyuan(王恩元),HE Xueqiu(何学秋),et al. Electromagnetic radiation laws of the stress distribution in working face[J]. Journal of China Coal Society(煤炭学报),2007,32(10):1019-1022.
[14] LIU Jie(刘杰),WANG Enyuan(王恩元),ZHAO Enlai(赵恩来),et al. Distribution and variation of mining-induced stress field in deep workface[J]. Journal of Mining&Safety Engineering(采矿与安全工程学报),2014,31(1):60-65.
[15] JIANG Fuxing(姜福兴),LIU Yi(刘懿),ZHANG Yichao(张益超),et al. A three-zone structure loading model of overlying strata and its application on rockburst prevention[J]. Chinese Journal of Rock Mechanics and Engineering(岩石力学与工程学报),2016,35(12):2398-2408.
[16] JIANG Fuxing(姜福兴),LIU Yi(刘懿),YANG Weili(杨伟利),et al. Relationship between rock burst and the three zone structure loading model in Yuncheng coal mine[J]. Journal of Mining&Safety Engineering(采矿与安全工程学报),2017,34(3):405-410.
[17] CUI Tiejun(崔铁军),LI Shasha(李莎莎),WANG Laigui(王来贵). On the mesoscopic process rock burst based on the dynamic theory[J]. Journal of Safety and Environment(安全与环境学报),2018,18(2):474-480.