Pressure relief mechanisms and effects of liberation seam mining in 1000-m-deep coal mines: A case study of the Huafeng coal mine in Tai’an, China

Authors

GAO Yanan, Shaanxi Key Laboratory Prevention and Control Technology for Coal Mine Water Hazard, Xi’an 710077, China; State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, China; School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, China; School of Architectural Engineering, Shanghai Zhongqiao Vocational and Technical University, Shanghai 201500, ChinaFollow
ZHANG Yao, State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, China; School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, China; School of Architectural Engineering, Shanghai Zhongqiao Vocational and Technical University, Shanghai 201500, ChinaFollow
ZHANG Defei, State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, China; School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, China; Huafeng Coal Mine of Xinwen Mining Group Co., Ltd., Tai’an 271413, China
ZHANG Yudong, School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, China
ZHAO Weidong, Huafeng Coal Mine of Xinwen Mining Group Co., Ltd., Tai’an 271413, China
YU Liyuan, State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, China; School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, China

Abstract

Liberation seam mining serves as an important approach to the prevention of deep dynamic disasters such as coal and gas outbursts, as well as rock bursts. Based on the Nos. 2613 and 2412 mining faces of a 1000-m-depth coal mine in the Huafeng Coal Mine in Tai’an, Shandong, this study investigated the engineering scientific issues such as the pressure relief mechanisms and effect evaluation of liberation seam mining through physical and numerical simulations. As a result, it determined the movement law of overburden strata and the characteristics of underground pressure after the mining of the liberation seam and ascertained the evolutionary laws of the stope stress and stratum displacement during the mining of the liberated seam. Accordingly, it evaluated the pressure relief effect of the liberation seam mining and the feasibility of the liberation seam mining based on various indices. The results are as follows: (1) During the mining of the liberation seam, the overburden strata gradually collapsed, forming a funnel-shaped, asymmetric multi-end fixed beam structure. After the liberation seam mining, quasi-cantilever beam structures, which provided permanent pressure relief protection for the liberated seam, were formed at the left and right ends of the stope, with left and right protection angles of 54° and 66°, respectively; (2) The overburden strata of the liberation seam can be divided into the protection zone of permanent pressure relief and the compaction zone of gangue in the goaf. Corresponding to the protection zone and the compaction zone, the maximum stress on the roof the of liberated seam was about 20 MPa and 36 MPa, respectively, and the maximum stress within the liberated seam was approximately 29 MPa and 24 MPa, respectively. The liberated seam was subjected to the combined effects of the two stress zones; (3) After the mining of the liberation seam, stress accumulated at both ends of its mining face, and the overburden strata in other zones were in the pressure relief state. The continuous propagation of the compaction zone affected the liberated seam, whose subsidence at distances of 50-100 m from the liberation seam roughly equaled the mining height; (4) During the mining of the liberated seam, the overburden rock showed a palling index (f) of 0.5, which was less than the critical value 0.7, indicating that the dynamic disaster of high underground pressure was unlikely to happen in the liberated seam. Moreover, the overburden strata’s disturbance range varied slightly compared to that before mining. In combination with the failure morphology of the overburden strata, it can be concluded that the liberated seam was always within the pressure relief range during its mining. Therefore, due to the sufficient pressure relief of the liberation seam, the mining of the liberated seam is feasible.

Keywords

1000-m-deep mine, liberation seam mining, pressure relief mechanism, pressure relief effect, feasibility of mining

DOI

10.12363/issn.1001-1986.22.12.0915

Recommended Citation

GAO Yanan, ZHANG Yao, ZHANG Defei, et al. (2023) "Pressure relief mechanisms and effects of liberation seam mining in 1000-m-deep coal mines: A case study of the Huafeng coal mine in Tai’an, China," Coal Geology & Exploration: Vol. 51: Iss. 8, Article 14.
DOI: 10.12363/issn.1001-1986.22.12.0915
Available at: https://cge.researchcommons.org/journal/vol51/iss8/14

Reference

[1] 李春元,左建平,张勇. 深部开采底板破坏与基本顶岩梁初次垮断的联动效应[J]. 岩土力学,2021,42(12):3301−3314.

LI Chunyuan,ZUO Jianping,ZHANG Yong. The linkage effect between floor failure and first weighting of the main roof in deep longwall mining[J]. Rock and Soil Mechanics,2021,42(12):3301−3314.

[2] 崔峰,张廷辉,来兴平,等. 冲击地压矿井不同采动强度下的开采扰动特征及其产能[J]. 煤炭学报,2021,46(12):3781−3793.

CUI Feng,ZHANG Tinghui,LAI Xingping,et al. Mining disturbance characteristics and productivity of rock burst mines under different mining intensities[J]. Journal of China Coal Society,2021,46(12):3781−3793.

[3] 赵善坤,齐庆新,李云鹏,等. 煤矿深部开采冲击地压应力控制技术理论与实践[J]. 煤炭学报,2020,45(Sup.2):626−636.

ZHAO Shankun,QI Qingxin,LI Yunpeng,et al. Theory and practice of rockburst stress control technology in deep coal mine[J]. Journal of China Coal Society,2020,45(Sup.2):626−636.

[4] CAI Wu,DOU Linming,SI Guangyao,et al. Fault–induced coal burst mechanism under mining–induced static and dynamic stresses[J]. Engineering,2021,7(5):687−700.

[5] KARACAN C Ö，RUIZ F A，COTÈ M，et al. Coal mine methane：A review of capture and utilization practices with benefits to mining safety and to greenhouse gas reduction[J]. International Journal of Coal Geology，2011，86(2–3)：121–156.

[6] LI Zhenlei,DOU Linming,CAI Wu,et al. Investigation and analysis of the rock burst mechanism induced within fault–pillars[J]. International Journal of Rock Mechanics and Mining Sciences,2014,70:192−200.

[7] 刘少虹,潘俊锋,刘金亮,等. 基于卸支耦合的冲击地压煤层卸压爆破参数优化[J]. 煤炭科学技术,2018,46(11):21−29.

LIU Shaohong,PAN Junfeng,LIU Jinliang,et al. Optimization of blasting parameters for rock burst coal seam based on pressure release and support coupling[J]. Coal Science and Technology,2018,46(11):21−29.

[8] 刘志刚,曹安业,井广成. 煤体卸压爆破参数正交试验优化设计研究[J]. 采矿与安全工程学报,2018,35(5):931−939.

LIU Zhigang,CAO Anye,JING Guangcheng. Research on parameters optimization of stress relief blasting in coal roadway using orthogonal experiment[J]. Journal of Mining & Safety Engineering,2018,35(5):931−939.

[9] 李兵,杜伟乾,李昱江,等. 煤层注水软化工法及效果分析[J]. 煤炭科技,2022,43(1):74−77.

LI Bing,DU Weiqian,LI Yujiang,et al. Coal seam water flooding softening method and effect analysis[J]. Coal Science and Technology Magazine,2022,43(1):74−77.

[10] 王超. 煤层注水防治冲击地压效果分析及可注性鉴定研究[J]. 煤炭工程,2018,50(1):92−95.

WANG Chao. Effect analysis of rock burst prevention and study on infusibility judging for coal seam water infusion[J]. Coal Engineering,2018,50(1):92−95.

[11] 贾传洋,蒋宇静,张学朋,等. 大直径钻孔卸压机理室内及数值试验研究[J]. 岩土工程学报,2017,39(6):1115−1122.

JIA Chuanyang,JIANG Yujing,ZHANG Xuepeng,et al. Laboratory and numerical experiments on pressure relief mechanism of large–diameter boreholes[J]. Chinese Journal of Geotechnical Engineering,2017,39(6):1115−1122.

[12] 李小彦,孙德全,谢风华,等. 大直径钻孔卸压对围岩强度与锚固力影响研究[J]. 煤矿安全,2022,53(1):79−84.

LI Xiaoyan,SUN Dequan,XIE Fenghua,et al. Research on the influence of large diameter borehole pressure relief on surrounding rock strength and anchoring force[J]. Safety in Coal Mines,2022,53(1):79−84.

[13] 杜涛涛,窦林名,蓝航. 定向水力致裂防冲原理数值模拟研究[J]. 西安科技大学学报,2012,32(4):444−449.

DU Taotao,DOU Linming,LAN Hang. Simulation on rockburst prevention by directional hydraulic fracture[J]. Journal of Xi’an University of Science and Technology,2012,32(4):444−449.

[14] 黄炳香,王友壮. 顶板钻孔割缝导向水压裂缝扩展的现场试验[J]. 煤炭学报,2015,40(9):2002−2008.

HUANG Bingxiang,WANG Youzhuang. Field investigation on crack propagation of directional hydraulic fracturing in hard roof[J]. Journal of China Coal Society,2015,40(9):2002−2008.

[15] 卢义玉,葛兆龙,李晓红,等. 脉冲射流割缝技术在石门揭煤中的应用研究[J]. 中国矿业大学学报,2010,39(1):55−58.

LU Yiyu,GE Zhaolong,LI Xiaohong,et al. Investigation of a self–excited pulsed water jet for rock cross–cutting to uncover coal[J]. Journal of China University of Mining & Technology,2010,39(1):55−58.

[16] 林柏泉,赵洋,刘厅,等. 水力割缝煤体多场耦合响应规律研究[J]. 西安科技大学学报,2017,37(5):662−667.

LIN Baiquan,ZHAO Yang,LIU Ting,et al. Coupling response law of multi–field in coal seam after hydraulic slotting[J]. Journal of Xi’an University of Science and Technology,2017,37(5):662−667.

[17] 张宏伟,朱峰,李云鹏,等. 液态CO₂致裂技术在冲击地压防治中的应用[J]. 煤炭科学技术,2017,45(12):23−29.

ZHANG Hongwei,ZHU Feng,LI Yunpeng,et al. Application of liquid CO₂ fracturing technique in rock burst control[J]. Coal Science and Technology,2017,45(12):23−29.

[18] 张东明,白鑫,尹光志,等. 低渗煤层液态CO₂相变定向射孔致裂增透技术及应用[J]. 煤炭学报,2018,43(7):1938−1950.

ZHANG Dongming,BAI Xin,YIN Guangzhi,et al. Research and application on technology of increased permeability by liquid CO₂ phase change directional jet fracturing in low–permeability coal seam[J]. Journal of China Coal Society,2018,43(7):1938−1950.

[19] 吴学松,买巧利,于贵良. 特厚煤层上部远距离解放层开采卸压效果研究[J]. 煤炭科技,2021,42(4):44−48.

WU Xuesong,MAI Qiaoli,YU Guiliang. Research on the decompression effect of long–distance liberation seam mining in the upper part of extra thick coal[J]. Coal Science and Technology Magazine,2021,42(4):44−48.

[20] 沈荣喜,王恩元,刘贞堂,等. 近距离下保护层开采防冲机理及技术研究[J]. 煤炭学报,2011,36(增刊1):63−67.

SHEN Rongxi,WANG Enyuan,LIU Zhentang,et al. Rockburst prevention mechanism and technique of close–distance lower protective seam mining[J]. Journal of China Coal Society,2011,36(Sup.1):63−67.

[21] 邵景忠. 区域性防治瓦斯突出措施:解放层的分类、作用原理及应用[J]. 煤炭技术,2008,27(6):91−92.

SHAO Jingzhong. Measures of regional prevention and cure gas outburst:Classify function and application of releasing coal seam[J]. Coal Technology,2008,27(6):91−92.

[22] 易恩兵. 深井强冲击煤层解放层开采防治冲击地压研究[J]. 煤炭技术,2014,33(5):126−128.

YI Enbing. Research on mine rock burst from liberated seam mining with high burst tendency in deep mine[J]. Coal Technology,2014,33(5):126−128.

[23] 杨勇翔. 开采解放层防治冲击地压的初步探讨[J]. 煤矿安全,1987(2):25−30.

YANG Yongxiang. Preliminary discussion on prevention and control of rock burst in mining liberated layer[J]. Safety in Coal Mines,1987(2):25−30.

[24] 马大勋. 关于上保护层的实验研究与探讨[J]. 煤炭学报,1986(3):1−9.

MA Daxun. Experimental research and discussion on extraction of upper protective seam[J]. Journal of China Coal Society,1986(3):1−9.

[25] TU Qingyi,CHENG Yuanping. Stress evolution and coal seam deformation through the mining of a remote upper protective layer[J]. Energy Sources,Part A:Recovery,Utilization,and Environmental Effects,2019,41(3):338−348.

[26] 王海锋. 采场下伏煤岩体卸压作用原理及在被保护层卸压瓦斯抽采中的应用[D]. 徐州：中国矿业大学，2008.

WANG Haifeng. Pressure relief functional principle of stope underlying coal–rock mass and application in gas extraction of protected coal seam[D]. Xuzhou：China University of Mining and Technology，2008.

[27] 王海锋,程远平,刘桂建,等. 被保护层保护范围的扩界及连续开采技术研究[J]. 采矿与安全工程学报,2013,30(4):595−599.

WANG Haifeng,CHENG Yuanping,LIU Guijian,et al. Range extender of protection and continuous mining technology of protected seam[J]. Journal of Mining & Safety Engineering,2013,30(4):595−599.

[28] 李明好. 下保护层开采卸压范围及卸压程度的研究[D]. 淮南：安徽理工大学，2005.

LI Minghao. Research on the range and degree of pressure relief during mining of the lower protective layer[D]. Huainan：Anhui University of Science and Technology，2005.

[29] 王洛锋. 深部大倾角强冲击厚煤层开采解放层卸压效果研究[D]. 北京：北京科技大学，2008.

WANG Luofeng. Study on destressing effects after mining protective seams of the deep thick coal seam with large obliquity and high burst liability[D]. Beijing：University of Science and Technology Beijing，2008.

[30] 王洛锋,姜福兴,于正兴. 深部强冲击厚煤层开采上、下解放层卸压效果相似模拟试验研究[J]. 岩土工程学报,2009,31(3):442−446.

WANG Luofeng,JIANG Fuxing,YU Zhengxing. Similar material simulation experiment on destressing effects of the deep thick coal seam with high burst liability after mining upper and lower protective seams[J]. Chinese Journal of Geotechnical Engineering,2009,31(3):442−446.

[31] GAO Rui,YU Bin,XIA Hongchun,et al. Reduction of stress acting on a thick,deep coal seam by protective–seam mining[J]. Energies,2017,10(8):1209.

[32] WANG Zhongchang,BIAN Wenrui. Analysis of pressure relief effect on the protective layer of hard roof and extra–thickness coal seam mining[J]. Geotechnical and Geological Engineering,2019,37(1):163−172.

[33] 吴向前,窦林名,吕长国,等. 上解放层开采对下煤层卸压作用研究[J]. 煤炭科学技术,2012,40(3):28−31.

WU Xiangqian,DOU Linming,LYU Changguo,et al. Study on upper liberated seam mining to pressure releasing function of low seam[J]. Coal Science and Technology,2012,40(3):28−31.

[34] CHENG Xiang,ZHAO Guangming,LI Yingming,et al. Mining–induced pressure–relief mechanism of coal–rock mass for different protective layer mining modes[J]. Advances in Materials Science and Engineering,2021(7):1−15.

[35] 涂敏,缪协兴,黄乃斌. 远程下保护层开采被保护煤层变形规律研究[J]. 采矿与安全工程学报,2006,23(3):253−257.

TU Min,MIAO Xiexing,HUANG Naibin. Deformation rule of protected coal seam exploited by using the long distance lower protective seam method[J]. Journal of Mining & Safety Engineering,2006,23(3):253−257.

[36] ZHANG Hongtu,WEN Zhihui,YAO Banghua,et al. Numerical simulation on stress evolution and deformation of overlying coal seam in lower protective layer mining[J]. Alexandria Engineering Journal,2020,59(5):3623−3633.

[37] 马占国,涂敏,马继刚,等. 远距离下保护层开采煤岩体变形特征[J]. 采矿与安全工程学报,2008,25(3):253−257.

MA Zhanguo,TU Min,MA Jigang,et al. Rock mass deformation characteristics for coal mining at remote lower protective seam[J]. Journal of Mining & Safety Engineering,2008,25(3):253−257.

[38] CHANG Zhongbao，HUI Qingbo，LI Yutong，et al. Optimization of roadway layout and its effect analysis for lower protective seam in fully mechanized caving mining[M]. Progress in Mine Safety Science and Engineering II，2014.

[39] 张玉栋. 千米强矿压深井解放层开采卸压机理及效果分析研究[D]. 徐州：中国矿业大学，2022.

ZHANG Yudong. Study on pressure relief mechanism and effect analysis of liberation seam mining with coal mine of strong ground pressure under the depth of 1000m[D]. Xuzhou：China University of Mining and Technology，2022.

[40] 刘金海,姜福兴,张宗文,等. 超前离层诱发矿震的机理及其微震特征[J]. 湖南科技大学学报 (自然科学版),2011,26(1):28−32.

LIU Jinhai,JIANG Fuxing,ZHANG Zongwen,et al. Mechanism of mine earthquake induced by lead separation and its microseismic characteristics[J]. Journal of Hunan University of Science & Technology (Natural Science Edition),2011,26(1):28−32.

[41] CASTRO L A M，GRABINSKY M W，MCCREATH D R. Damage initiation through extension fracturing in a moderately jointed brittle rock mass[J]. International Journal of Rock Mechanics & Mining Sciences，1997，34(3/4)：110.

[42] CASTRO L A M，MCCREATH D R，KAISER P. Rockmass strength determination from breakouts in tunnels and boreholes[J]. International Society for Rock Mechanics，1995.

[43] ANGELIER J. Sur l’analyse de mesures recueillies dans des sites faillés:l’utilité d’une confrontation entre les méthodes dynamiques et cinématiques:Erratum[J]. Comptes–Rendus de l’Académie des Sciences,1976,283:466.

[44] ORIFE T,LISLE R J. Numerical processing of palaeostress results[J]. Journal of Structural Geology,2003,25(6):949−957.