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放顶煤开采过程中,由于顶煤厚度的变化,使得煤矸流场规律发生变化,影响了顶煤的放落回收。基于鹤壁十矿在煤层厚度变化较大条件下放顶煤开采的实际,应用PFC2D计算程序,模拟分析了顶煤厚度变化,即采放比不同对煤矸流场特征和顶煤放出规律的影响。结果表明:顶煤损失是随放煤循环逐渐积累的过程,煤矸流动的速度场和接触力场以放煤口为中心呈半拱形状,距放煤口距离越小,接触力越小。
During the process of top coal caving, due to the change of top coal thickness, the rule of coal gangue flow field changes, which affects the falling and recovery of top coal. Based on the actual practice of top coal caving in Hebi No.10 coal seam with large variation of coal seam thickness, the PFC2D calculation program was used to simulate and analyze the influence of different top coal thickness on coal gangue flow field characteristics and top coal releasing law. The results show that the top coal loss is a process of gradual accumulation with the coal circulation cycle. The velocity field and the contact force field of coal gangue are semi-arched with the caving mouth as the center. The smaller the distance from the coal caving mouth, the smaller the contact force.