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倾斜煤层工作面煤厚对顶煤放出特征的影响研究

Research on influence of coal seam thickness on caving characteristics of top-coal in inclined coal seam fully - mechanized caving faces

  • 摘要: 鹤煤六矿2125综放工作面煤层赋存不稳定,煤层厚度为0.4 ~24 m,煤层倾角为8°~35°。针对倾斜厚煤层综放开采顶煤放出难度大、采放不协调、混矸率高等问题,基于多种煤层赋存条件采用控制变量方法,利用CDEM数值模拟软件构建颗粒随机分布的放顶煤工作面数值模型,研究了不同煤层倾角(煤层倾角25°、30°、35°)、不同顶煤厚度(顶煤厚度6、10、15 m)下初始煤岩分界线形态、顶煤放出体发育形态特征、煤岩分界线演化规律,得到如下结论:相同顶煤厚度情况下,随着煤层倾角增加,靠近工作面上端头一侧的煤岩分界线逐渐被拉长趋于平缓,靠近工作面下端头一侧的煤岩分界线则受到岩石流压制愈显陡峭,放煤漏斗发育宽度、单次放煤量呈近似线性正相关增长趋势, 其初始顶煤放出体的特征由近似竖椭球体—类圆椭球体—横向椭球体进行演化; 相同煤层倾角情况下,随着煤层厚度增加,顶煤放出体纵向高度扩展的同时,其横向宽度的扩展也呈现出增长趋势,其纵向发育程度会超过横向发展程度,表现为煤岩分界线倾斜程度随着顶煤厚度的增加而增大,放煤漏斗的发育宽度呈近似线性正相关的趋势;通过数值模拟与现场工业性试验相结合的方法,统计了顺序放煤、间隔放煤两种放煤方式下的每一个放煤口的放煤量,与数值模拟结果相符。

     

    Abstract: The coal seam at the 2125 fully mechanized top-coal caving face in Hebi Coal Mine No. 6 exhibits unstable occurrence, with a thickness ranging from 0.4 m to 24 m and a dip angle varying between 8° and 35°. To address challenges such as difficulties in top-coal caving, incoordination between coal cutting and caving, and high rates of gangue mixing during fully mechanized caving in inclined thick coal seams, a control variable method was adopted based on diverse coal seam occurrence conditions. Utilizing the CDEM numerical simulation software, a numerical model of the top-coal caving face with random particle distribution was established. The initial coal-rock interface morphology, developmental characteristics of top-coal caving bodies, and evolution patterns of the coal-rock interface were investigated under varying coal seam dip angles (25°, 30°, 35°) and top-coal thicknesses (6, 10, 15 m). Key conclusions are as follows: Under constant top-coal thickness, as the coal seam dip angle increases:The coal-rock interface near the upper end of the working face gradually elongates and flattens, while the interface near the lower end becomes steeper due to suppression by rock flow.The width of the caving funnel and single-cycle caving volume exhibit an approximately linear positive correlation with increasing dip angle.The initial caving body evolves from a near-vertical ellipsoid → quasi-circular ellipsoid → horizontal ellipsoid. Under constant coal seam dip angle, as the top-coal thickness increases: The caving body expands both vertically and transversely, with vertical growth exceeding transverse development. The inclination of the coal-rock interface intensifies with greater top-coal thickness. The caving funnel width shows an approximately linear positive correlation with thickness. Validation via numerical simulation and field trials: Caving volumes at individual outlets under sequential caving and interval caving modes were statistically analyzed, demonstrating consistency with numerical results.

     

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