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| A model for top-coal cavability assessment and its application in longwall top-coal caving |
| WANG Zhaohui1,2,WANG Jiachen1,2,WANG Kai1 |
(1. College of Resources and Safety Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;
2. Top-coal Caving Mining Research of Coal Mining Industry,China University of Mining and Technology(Beijing),
Beijing 100083,China) |
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Abstract In order to realize quantitative analysis of top-coal cavability and to improve top-coal recovery rate,evolution of ultrasonic wave velocity in uniaxially compressed coal is investigated and an ultrasonic model is established and applied to longwall top-coal cavability assessment by using lab test,theoretical analysis,numerical simulation and field measurement. Ultrasonic propagation speed in the coal remains unchanged during the elastic stage,decreases monotonically with fracture expanding in the subsequent yield stage,and tends to be stable again in the residual stage. Based on evolving features of the velocity during progressive failure process of the coal,distribution of the ultrasonic wave velocity ahead of the longwall face is divided into three classifications including single phase(I),double phases(I–II) and three phases (I–III). For the single phase distribution,top coal is intact and the top-coal caving method is inapplicable. For the double phase distribution,top-coal cavability is bad and the recovery rate is low(50%–70%). Top-coal cavability is good and the recovery rate is higher than 70% for the three phase distribution. Cumulative plastic strain is used to characterize the development of fractures in the coal,and an ultasonic model is proposed for predicting the wave velocity. The ultrasonic model is coupled with the constitutive model to achieve accurate simulation of progressive failure process and ultrasonic wave velocity evolution in compressed coal. The developed model is validated by comparisons against experimental data and applied to assess longwall top-coal cavability in Xinliu coal mine. Numerical results indicate that the ultrasonic wave velocity distribution belongs to I–III type,which is verified by the in situ measured top-coal recovery rate of 83.3%. Accuracy of the prediction is also verified by field measurements of the vertical stress and the ultrasonic wave velocity. Thus,the model can be used to predict top-coal cavability in different mining conditions.
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[1] 王家臣. 厚煤层开采理论与技术[M]. 北京:冶金工业出版社,2009:47–51.(WANG Jiachen. The theory and technique on the thick coal seam mining[M]. Beijing:Metallurgical Industry Press,2009:47–51.(in Chinese))
[2] WANG J H. Development and prospect on fully mechanized top-coal caving in Chinese coal mines[J]. International Journal of Coal Science and Technology,2014,1(3):253–260.
[3] 樊运策,师文林,张长根,等. 潞安王庄煤矿综放工作面回采损失的量化分析[J]. 煤炭学报,1997,22(6):48–53.(FAN Yunce,SHI Wenlin,ZHANG Changgen,et al. Quantification analysis of mining loss in fully mechanized caving face in Wangzhuang coal mine in Luan coal mining bureau[J]. Journal of China Coal Society,1997,22(6):48–53.(in Chinese))
[4] 樊运策. 综放工作面冒落顶煤放出控制[J]. 煤炭学报,2001,26(6):606–610.(FAN Yunce. Control on top coal caving in long wall top coal caving working face[J]. Journal of China Coal Society,2001,26(6):606–610.(in Chinese))
[5] 张 勇,吴 健. 放顶煤开采顶煤的裂移度及顶煤可放性[J].中国矿业大学学报,2000,29(5):64–67.(ZHANG Yong,WU Jian. Crack-movement degree and caving characteristic of top-coal in longwall top-coal caving mining[J]. Journal of China University of Mining and Technology,2000,29(5):64–67.(in Chinese))
[6] 吴 健,张 勇. 顶煤裂隙的发展趋势及其对注水防尘的影响[J]. 煤炭学报,1998,23(6):22–26.(WU Jian,ZHANG Yong. Developed trend of fracture in top-coal and its influence on water injection[J]. Journal of China Coal Society,1998,23(6):22–26.(in Chinese))
[7] 陈忠辉,谢和平,林忠明. 综放开采顶煤冒放性的损伤力学分析[J]. 岩石力学与工程学报,2002,21(8):1 136–1 140.(CHEN Zhonghui,XIE Heping,LIN Zhongming. Study on falling ability of top coal during top coal caving by damage mechanics[J]. Chinese Journal of Rock Mechanics and Engineering,2002,21(8):1 136–1 140.(in Chinese))
[8] 陈忠辉,谢和平,王家臣. 综放开采顶煤三维变形、破坏的数值分析[J]. 岩石力学与工程学报,2002,21(3):309–313.(CHEN Zhonghui,XIE Heping,WANG Jiachen. Three-dimensional deformation and failure of top coal analyzed by numerical simulation[J]. Chinese Journal of Rock Mechanics and Engineering,2002,21(3):309–313.(in Chinese))
[9] 谢和平,赵旭清. 综放开采顶煤体的连续损伤破坏分析[J]. 中国矿业大学学报,2001,30(4):323–327.(XIE Heping,ZHAO Xuqing. Analysis of continuous damage and failure of top-coal[J]. Journal of China University of Mining and Technology,2001,30(4):323–327.(in Chinese))
[10] 靳钟铭. 放顶煤开采理论[M]. 北京:煤炭工业出版社,2001:70–72.(JIN Zhongming. Top-coal caving theories[M]. Beijing:Coal Industry Press,2001:70–72.(in Chinese))
[11] 王家臣,王兆会. 综放开采顶煤在加卸载复合作用下的破坏机 理[J]. 同煤科技,2017,3(1):1–8.(WANG Jiachen,WANG Zhaohui. Failure mechanism of top coal under the combined effect of loading-unloading process[J]. Science and Technology of Datong Coal Mining Administration,2017,3(1):1–8.(in Chinese))
[12] 王家臣,白希军,吴志山,等. 坚硬煤体综放开采顶煤破碎块度的研究[J]. 煤炭学报,2000,25(3):238–242.(WANG Jiachen,BAI Xijun,WU Zhishan,et al. Research on the fractured blocks of the top-coal in the longwall top-coal caving technique of the hard coal seam[J]. Journal of China Coal Society,2000,25(3):238–242.(in Chinese))
[13] 王卫军,朱川曲,熊仁钦. 急倾斜煤层顶煤可放性识别的神经网络模型[J]. 煤炭学报,2000,25(1):38–41.(WANG Weijun,ZHU Chuanqu,XIONG Renqin. An artificial neural network for distinguishing the difficulty degree of roof coal caving of steep seam[J]. Journal of China Coal Society,2000,25(1):38–41.(in Chinese))
[14] 刘金海,冯 涛,王卫军,等. 急倾斜煤层顶煤可放性识别的距离判别方法及应用[J]. 煤炭学报,2008,33(6):601–605.(LIU Jinhai,FENG Tao,WANG Weijun,et al. Distance discriminant analysis method for distinguishing the difficulty degree of top-coal caving in steep seam and its application[J]. Journal of China Coal Society,2008,33(6):601–605.(in Chinese))
[15] 朱川曲,缪协兴. 急倾斜煤层顶煤可放性评价模型及应用[J]. 煤炭学报,2002,27(2):134–138.(ZHU Chuanqu,MIAO Xiexing. Model and its application on the evaluation of degree of difficulty of top coal caving in steep seam[J]. Journal of China Coal Society,2002,27(2):134–138.(in Chinese))
[16] 范世民,胡学军. 放顶煤开采顶煤冒放性分类及其在潞安矿区的应用[J]. 煤炭学报,2005,30(2):177–181.(FAN Shimin,HU Xuejun. The classification of top coal cavability and its application in Lu′an coal mine[J]. Journal of China Coal Society,2005,30(2):177–181. (in Chinese))
[17] 董陇军,李夕兵,白云飞. 急倾斜煤层顶煤可放性分类预测的Fisher判别分析模型及应用[J]. 煤炭学报,2009,34(1):58–63.(DONG Longjun,LI Xibing,BAI Yunfei. A Fisher discriminant analysis model for classifying top coal capability of the steep seam[J]. Journal of China Coal Society,2009,34(1):58–63.(in Chinese))
[18] 潘卫东. 综放开采中煤体属性的超声波探测技术[M]. 北京:煤炭工业出版社,2014:60–74.(PAN Weidong. Measuring technique of ultrasonic wave velocity in longwall top-coal caving mining[M]. Beijing:Coal Industry Press,2014:60–74.(in Chinese))
[19] 王兆会. 综放开采顶煤破坏机理与冒放性判别方法研究[博士学位论文][D]. 北京:中国矿业大学(北京),2017.(WANG Zhaohui. Failure mechanism and cavability evaluation of top coal in longwall top-coal caving mining[Ph. D. Thesis][D]. Beijing:China University of Mining and Technology(Beijing),2017.(in Chinese))
[20] ALEHOSSEIN H,POULSEN B A. Stress analysis of longwall top coal caving[J]. International Journal of Rock Mechanics and Mining Sciences,2010,47:30–41.
[21] VAKILI A,HEBBLEWHITE B K. A new cavability assessment criterion for longwall top coal caving[J]. International Journal of Rock Mechanics and Mining Sciences,2010,47:1 317–1 329.
[22] YASITLI N E,UNVER B. 3D numerical modeling of longwall mining with top-coal caving[J]. International Journal of Rock Mechanics and Mining Sciences,2005,42:219–235.
[23] KERN H,SCHENK V. A model of velocity structure beneath Calabria,southern Italy,based on laboratory data[J]. Earth and Planetary Science Letters,1988,87(3):325–337.
[24] 樊秀峰,简文彬. 砂岩疲劳特性的超声波速法试验研究[J]. 岩石力学与工程学报,2008,27(3):557–563.(FAN Xiufeng,JIAN Wenbin. Experimental research on fatigue characteristics of sandstone using ultrasonic wave velocity method[J]. Chinese Journal of Rock Mechanics and Engineering,2008,27(3):557–563.(in Chinese))
[25] 朱劲松,宋玉普. 混凝土双轴抗压疲劳损伤特性的超声波速法研 究[J]. 岩石力学与工程学报,2004,23(13):2 230–2 234.(ZHU Jinsong,SONG Yupu. Research on fatigue damage of concrete under biaxial compressive loading using ultrasonic velocity method[J]. Chinese Journal of Rock Mechanics and Engineering,2004,23(13):2 230–2 234.(in Chinese))
[26] WANG J C,WANG Z H,YANG S L. A coupled macro- and meso- mechanical model for heterogeneous coal[J]. International Journal of Rock Mechanics and Mining Sciences,2017,94:64–81.
[27] WANG J C,YANG S L,LI Y,et al. Caving mechanisms of loose top-coal in longwall top-coal caving mining method[J]. International Journal of Rock Mechanics and Mining Sciences,2014,71:160–170.
[28] 王家臣,张锦旺,杨胜利,等. 多夹矸近水平煤层综放开采顶煤三维放出规律[J]. 煤炭学报,2015,40(5):979–987.(WANG Jiachen,ZHANG Jinwang,YANG Shengli,et al. 3-D movement law of top-coal in near horizontal coal seam with multi-gangue under cavingmining technique[J]. Journal of China Coal Society,2015,40(5):979–987.(in Chinese))
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