大采高综放开采顶煤放出的煤矸流场特征研究

Research on Coal-Gangue Flow Field Character Resulted from Great Cutting Height Fully Mechanized Top Coal Caving

采用理论和散体模型实验分析了大采高综放开采放煤口参数、采放比、放煤工序和放煤步距对煤矸流场的影响.大采高综放开采煤矸流场特征主要表现为:1)支架移架使顶煤放落后顶煤层位线和煤矸分界线的斜率变陡,明显比普通采高条件下的斜率大;2)放煤过程中煤矸的流动速度变快,在相同放煤步距条件下,在采高水平上煤矸分界线与支架顶梁末端的距离缩小;3)受采放比、掩护梁角度和放煤口尺寸影响而易于混矸.合理放煤步距移架后放煤前的煤矸分界线应略偏后于尾梁下部边界.基于以上研究结果,确定了大采高低位综放开采给定采放比、放煤口尺寸和煤矸块度条件下最佳放煤工艺参数.

The effect of drawing top coal window parameter, drawing procedure, and drawing interval on coal-gangue flow field resulted from great mining height fully mechanized top coal caving was analyzed based on theory and loose material model experiment. Coal-gangue flow field characters are that 1） slope coefficient of top-coal layer and coal-gangue demarcation line become much steeper than that under the condition of ordinary mining height after supports have been removed and coal caved, 2） the flow velocity of coal-gangue during the processe of drawing top coal becomes faster, and distance between coal-gangue demarcation line and the end of support top beam at the level of cutting height under the condition of same top coal drawing interval becomes shortened, 3） gangue is easy to mix into top coal affected by the cutting/drawing height ratio, shield beam angle, and the size of drawing top coal window. Therefore, coal-gangue demarcation line before drawing top coal should be in the place behind the lower boundary of tail boom end. Based on above study result, we determined optimum parameters of drawing top coal, which are cutting/drawing ratio, size of drawing coal window, and size of coal-gangue fragmentals.