Abstract This work proposed a progressive-sectional failure model (PSFM) based on Particle Flow Code (PFC) to simulate top coal drawing process in longwall top coal caving (LTCC) mining. The progressive-sectional fracturing of top coal was reproduced in simulation. 4 drawing schemes are numerically performed by considering drawing sequences and strategies. The results of simulations were compared in terms of top coal drawn out mass, drawing body, top coal recovery ratio (TCRR), top coal loss, etc. The results show that TCRR in PSFM is closer to average TCRR based on 9 LTCC coal mines measured in-situ. The top coal loss in PSFM is larger than loose granular model (LGM). The top coal boundary (TCB) in PSFM shows a “step” subsidence and is different from that in LGM. The factors to influence initial drawing body (IDB) are comprehensively analysed. A new mathematical model was proposed to specifically characterize IDB in LTCC. The results show that new model is well consistent with simulation results and is much more effective and accurate than former models.

中文翻译：

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长壁放顶煤裂隙顶煤抽采机理

摘要 本文提出了一种基于粒子流编码（PFC）的渐进截面破坏模型（PSFM）来模拟长壁放顶煤（LTCC）开采中的顶煤抽采过程。在模拟中再现了顶煤的连续分段压裂。通过考虑绘制顺序和策略，对4种绘制方案进行了数值计算。从顶煤抽出质量、牵引体、顶煤回收率（TCRR）、顶煤损失等方面对模拟结果进行了比较，结果表明PSFM中的TCRR更接近基于9个LTCC煤矿的平均TCRR原位测量。PSFM 中的顶部煤损失大于松散颗粒模型（LGM）。PSFM 煤顶边界（TCB）呈现“阶梯”沉降，与 LGM 不同。综合分析了影响初始绘图体（IDB）的因素。提出了一种新的数学模型来专门表征 LTCC 中的 IDB。结果表明，新模型与仿真结果吻合良好，比以前的模型更有效、更准确。