块度级配对散体顶煤流动特性影响的试验研究
|
摘要
掌握破碎后散体顶煤的流动特性和放出规律是综放开采优化放煤工艺参数、提高顶煤采出率、降低含矸率的重要基础。不同块度的顶煤在松散煤块集合体中所占的比例称之为块度级配,块度级配是松散煤体流动特性的重要影响因素之一。为了研究块度级配对散体顶煤流动特性的影响,基于自主研制的放煤试验台,采用物理模拟试验和理论分析相结合的方法探究了块度级配对初始放煤量、颗粒运移轨迹以及煤岩分界面演化特征的影响。不同块度级配条件下的放煤试验结果表明,初始放煤量随顶煤平均块度的增大而增大;放出顶煤的块度级配变化显著,小块度顶煤占比高时,大块顶煤更易被放出;反之,大块顶煤因成拱频繁而放出量少;初始煤岩分界面演化过程中其最低点由放煤口中心线逐渐偏向采空区侧,且顶煤平均块度越大越显著,其运动轨迹基本符合横向抛物线形式。支架上方顶煤颗粒运动速度明显快于采空区侧顶煤颗粒;顶煤平均块度较小时,顶煤颗粒运动速度较快,成拱次数较少;顶煤通过放煤口以后,顶煤流动扩散角随顶煤平均块度的增大而增大。基于散体介质力学理论推导了支架侧和采空区侧初始煤岩分界面动态演化方程,结合放煤试验结果确定了不同顶煤块度级配条件下煤岩分界面理论方程的修正系数取值:支架侧初始煤岩分界面理论方程的修正系数k_R的取值为0.30～0. 35,采空区侧分界面理论方程的修正系数|k_L|的取值为0.25～0.28;讨论了顶煤块度级配对方程修正系数的影响规律,发现随着顶煤平均块度的增大,k_R和|k_L|的取值范围呈增大趋势。
A good understanding of flow characteristics and drawing mechanism of loose top coal is an important foundation for optimizing the drawing parameters, increasing the top coal recovery and reducing the rock mixed ratio in longwall top coal caving. The proportion of top coal in different sizes is called size distribution, and size distribution is one of important factors affecting the flow characteristics of loose top coal. In order to study the effect of size distribution on the flow characteristics of loose top coal, both physical simulation experiments and theoretical analysis were conducted based on a self-developed experimental device. The initial drawing volume,the flowing path of top coal and the evolution characteristics of initial boundary of top coal were investigated in depth. The results show that under the different size distribution of top coal, the initial drawing volume increases with the increase of average size of top coal.The size distribution of top coal draw out changes significantly, and when the proportion of small top coal is higher, the large top coal is easier to be drawn. In contrast,the large top coal is more difficult to be drawn due to the frequent formation of arch structures. The lowest point of the initial boundary of top coal is gradually moved toward the gob side other than the center line of the shield opening during the top coal drawing process. The moving path of the lowest point is basically consistent with the horizontal parabolic form, and the larger the average top coal size is, the more obvious the characteristic is. The speed of top coal particles above the caving support is obviously faster than that of top coal particles near the gob side. When the average size of top coal is small,the speed is faster and the number of arching frequency is relatively low. After the top coal passes through the shield opening, the diffusion angle of top coal flow increases with the increase of average size of top coal. The dynamic evolution equations of the initial boundary of top coal on the support side and gob side are proposed based on granular medium mechanics and the correction coefficients of the equations are determined according to the physical experimental data. The correction coefficient of the equation on the support side(kR) is in the range of 0. 30-0. 35 while the correction coefficient of the equation on the gob side( |k_L|) is between 0. 25 and 0. 28. The effect of size distribution on the correction coefficients is also discussed. The value of k_R and |k_L| increases with the increase of average size of top coal.
A good understanding of flow characteristics and drawing mechanism of loose top coal is an important foundation for optimizing the drawing parameters, increasing the top coal recovery and reducing the rock mixed ratio in longwall top coal caving. The proportion of top coal in different sizes is called size distribution, and size distribution is one of important factors affecting the flow characteristics of loose top coal. In order to study the effect of size distribution on the flow characteristics of loose top coal, both physical simulation experiments and theoretical analysis were conducted based on a self-developed experimental device. The initial drawing volume,the flowing path of top coal and the evolution characteristics of initial boundary of top coal were investigated in depth. The results show that under the different size distribution of top coal, the initial drawing volume increases with the increase of average size of top coal.The size distribution of top coal draw out changes significantly, and when the proportion of small top coal is higher, the large top coal is easier to be drawn. In contrast,the large top coal is more difficult to be drawn due to the frequent formation of arch structures. The lowest point of the initial boundary of top coal is gradually moved toward the gob side other than the center line of the shield opening during the top coal drawing process. The moving path of the lowest point is basically consistent with the horizontal parabolic form, and the larger the average top coal size is, the more obvious the characteristic is. The speed of top coal particles above the caving support is obviously faster than that of top coal particles near the gob side. When the average size of top coal is small,the speed is faster and the number of arching frequency is relatively low. After the top coal passes through the shield opening, the diffusion angle of top coal flow increases with the increase of average size of top coal. The dynamic evolution equations of the initial boundary of top coal on the support side and gob side are proposed based on granular medium mechanics and the correction coefficients of the equations are determined according to the physical experimental data. The correction coefficient of the equation on the support side(kR) is in the range of 0. 30-0. 35 while the correction coefficient of the equation on the gob side( |k_L|) is between 0. 25 and 0. 28. The effect of size distribution on the correction coefficients is also discussed. The value of k_R and |k_L| increases with the increase of average size of top coal.
引文
[1]王家臣,张锦旺,王兆会.放顶煤开采基础理论与应用[M].北京:科学出版社,2018:3-8.
[2] WANG Guofa,PANG Yihui. Surrounding rock control theory and longwall mining technology innovation[J]. International Journal of Coal Science&Technology,2017,4(4):301-309.
[3] QIAO Jianyong. Julia sets and complex singularities of free energies[J]. Memoirs of American Mathematical Society,2015,234(1102):1-85.
[4]王家臣,宋正阳,张锦旺,等.综放开采顶煤放出体理论计算模型[J].煤炭学报,2016,41(2):352-358.WANG Jiachen,SONG Zhengyang,ZHANG Jinwang,et al. Theoretical model of drawing body in LTCC mining[J]. Journal of China Coal Society,2016,41(2):352-358.
[5] WANG Jinhua,YU Bin,KANG Hongpu,et al. Key technologies and equipment for a fully mechanized top-coal caving operation with a large mining height at ultra-thick coal seams[J]. International Journal of Coal Science&Technology,2015,2(2):97-161.
[6]曹胜根,郭金刚,叶永红.块度对顶煤放出率的影响分析[J].煤炭科学技术,2004,32(4):61-63.CAO Shenggen,GUO Jingang, YE Yonggong. Analysis on coal size influenced to caving output rate[J]. Coal Science and Technology,2004,32(4):61-63.
[7]张勇,司艳龙,石亮.块度对顶煤放出率影响的数值模拟分析[J].采矿与安全工程学报,2011,28(2):247-251.ZHANG Yong,SI Yanlong,SHI Liang. Numerical simulation of the effect of particle size on coal caving ratio[J]. Journal of Mining&Safety Engineering,2011,28(2):247-251.
[8]刘长友,黄炳香,吴锋锋,等.煤岩块度对综放开采煤岩冒放规律及放煤参数的影响研究[A].煤炭开采新理论与新技术——中国煤炭学会开采专业委员会2006年学术年会论文集[C].徐州:中国矿业大学出版社,2006:18-23.LIU Changyou, HUANG Bingxiang, WU fengfeng, et al. Influence of coal and rock fragmentation on coal and rock caving law and coal drawing parameters in top coal caving mining[A]. New theories and techniques in coal mining-Proceedings of the 2006 annual academic conference of specialized committee of china coal society[C], Xuzhou:China University of Mining and Technology Press,2006:18-23.
[9]刘长友,黄炳香,吴锋锋,等.综放开采顶煤破断冒放的块度理论及应用[J].采矿与安全工程学报,2006,23(1):56-61.LIU Changyou,HUANG Bingxiang, WU fengfeng,et al. Fragment dimension theory and its application in fully mechanized t op coal caving[J]. Journal of Mining&Safety Engineering,2006,23(1):56-61.
[10]王家臣,张锦旺.综放开采顶煤放出规律的BBR研究[J].煤炭学报,2015,40(3):487-493.WANG Jiachen,ZHANG Jinwang. BBR study of top-coal drawing law in longwall top-coal caving mining[J]. Journal of China Coal Society,2015,40(3):487-493.
[11]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 caving mining technique[J]. Journal of China Coal Society,2015,40(5):979-987.
[12] ZHANG Jinwang,WANG Jiachen, WEI Weijie,et al. Experimental and numerical investigation on coal drawing from thick steep seam with longwall top coal caving mining[J]. Arabian Journal of Geosciences,2018,11(5):96.
[13] WANG Jiachen, ZHANG Jinwang, LI Zhaolong. A new research system for caving mechanism analysis and its application to sublevel top-coal caving mining[J]. International Journal of Rock Mechanics and Mining Sciences,2016,88(10):273-285.
[14]张锦旺,王家臣,魏炜杰.工作面倾角对综放开采散体顶煤放出规律的影响[J].中国矿业大学学报,2018,47(4):805-814.ZHANG Jinwang, WANG Jiachen, WEI Weijie, et al. Effect offace dip angle on the drawing mechanism in longwall top-coal caving mining[J]. Journal of China University of Mining and Technology,2018,47(4):805-814.
[15] WEI Weijie,SONG Zhengyang,ZHANG Jinwang. Theoretical equation of initial lop-coal boundary in longwall top-coal caving mining[J]. International Journal of Mining and Mineral Engineering,2018,9:157-176.
[16]王家臣,宋正阳.综放开采散体顶煤初始煤岩分界面特征及控制方法[J].煤炭工程,2015,47(7):1-4.WANG Jiachen,SONG Zhengyang. Characteristic and control method of initial interface between coal and rock under fully mechanized loose top coal caving[J]. Coal Engineering,2015,47(7):1-4.
[17] MELO F,VIVANCO F,FUENTES C,et al. On drawbody shapes:From Bergmark-Roos to kinematic models[J]. International Journal of Rock Mechanics&Mining Sciences,2007,44:77-86.
[2] WANG Guofa,PANG Yihui. Surrounding rock control theory and longwall mining technology innovation[J]. International Journal of Coal Science&Technology,2017,4(4):301-309.
[3] QIAO Jianyong. Julia sets and complex singularities of free energies[J]. Memoirs of American Mathematical Society,2015,234(1102):1-85.
[4]王家臣,宋正阳,张锦旺,等.综放开采顶煤放出体理论计算模型[J].煤炭学报,2016,41(2):352-358.WANG Jiachen,SONG Zhengyang,ZHANG Jinwang,et al. Theoretical model of drawing body in LTCC mining[J]. Journal of China Coal Society,2016,41(2):352-358.
[5] WANG Jinhua,YU Bin,KANG Hongpu,et al. Key technologies and equipment for a fully mechanized top-coal caving operation with a large mining height at ultra-thick coal seams[J]. International Journal of Coal Science&Technology,2015,2(2):97-161.
[6]曹胜根,郭金刚,叶永红.块度对顶煤放出率的影响分析[J].煤炭科学技术,2004,32(4):61-63.CAO Shenggen,GUO Jingang, YE Yonggong. Analysis on coal size influenced to caving output rate[J]. Coal Science and Technology,2004,32(4):61-63.
[7]张勇,司艳龙,石亮.块度对顶煤放出率影响的数值模拟分析[J].采矿与安全工程学报,2011,28(2):247-251.ZHANG Yong,SI Yanlong,SHI Liang. Numerical simulation of the effect of particle size on coal caving ratio[J]. Journal of Mining&Safety Engineering,2011,28(2):247-251.
[8]刘长友,黄炳香,吴锋锋,等.煤岩块度对综放开采煤岩冒放规律及放煤参数的影响研究[A].煤炭开采新理论与新技术——中国煤炭学会开采专业委员会2006年学术年会论文集[C].徐州:中国矿业大学出版社,2006:18-23.LIU Changyou, HUANG Bingxiang, WU fengfeng, et al. Influence of coal and rock fragmentation on coal and rock caving law and coal drawing parameters in top coal caving mining[A]. New theories and techniques in coal mining-Proceedings of the 2006 annual academic conference of specialized committee of china coal society[C], Xuzhou:China University of Mining and Technology Press,2006:18-23.
[9]刘长友,黄炳香,吴锋锋,等.综放开采顶煤破断冒放的块度理论及应用[J].采矿与安全工程学报,2006,23(1):56-61.LIU Changyou,HUANG Bingxiang, WU fengfeng,et al. Fragment dimension theory and its application in fully mechanized t op coal caving[J]. Journal of Mining&Safety Engineering,2006,23(1):56-61.
[10]王家臣,张锦旺.综放开采顶煤放出规律的BBR研究[J].煤炭学报,2015,40(3):487-493.WANG Jiachen,ZHANG Jinwang. BBR study of top-coal drawing law in longwall top-coal caving mining[J]. Journal of China Coal Society,2015,40(3):487-493.
[11]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 caving mining technique[J]. Journal of China Coal Society,2015,40(5):979-987.
[12] ZHANG Jinwang,WANG Jiachen, WEI Weijie,et al. Experimental and numerical investigation on coal drawing from thick steep seam with longwall top coal caving mining[J]. Arabian Journal of Geosciences,2018,11(5):96.
[13] WANG Jiachen, ZHANG Jinwang, LI Zhaolong. A new research system for caving mechanism analysis and its application to sublevel top-coal caving mining[J]. International Journal of Rock Mechanics and Mining Sciences,2016,88(10):273-285.
[14]张锦旺,王家臣,魏炜杰.工作面倾角对综放开采散体顶煤放出规律的影响[J].中国矿业大学学报,2018,47(4):805-814.ZHANG Jinwang, WANG Jiachen, WEI Weijie, et al. Effect offace dip angle on the drawing mechanism in longwall top-coal caving mining[J]. Journal of China University of Mining and Technology,2018,47(4):805-814.
[15] WEI Weijie,SONG Zhengyang,ZHANG Jinwang. Theoretical equation of initial lop-coal boundary in longwall top-coal caving mining[J]. International Journal of Mining and Mineral Engineering,2018,9:157-176.
[16]王家臣,宋正阳.综放开采散体顶煤初始煤岩分界面特征及控制方法[J].煤炭工程,2015,47(7):1-4.WANG Jiachen,SONG Zhengyang. Characteristic and control method of initial interface between coal and rock under fully mechanized loose top coal caving[J]. Coal Engineering,2015,47(7):1-4.
[17] MELO F,VIVANCO F,FUENTES C,et al. On drawbody shapes:From Bergmark-Roos to kinematic models[J]. International Journal of Rock Mechanics&Mining Sciences,2007,44:77-86.