This research focuses on the strata control issues in a Bord and Pillar depillaring working under the influence of dead load condition of voluminous and fragmented softcover of overburden dump material. It reports the modeling of a mine working through the FLAC 2D software under the Indian geo-mining conditions. The modeling results of an actual mine working under softcover were compared with that under the intact overburden condition to assess the influence of the soft overburden over the depillaring working. The modeling work involved progressive caving of the strata and the cyclic goaf filling following the model-simulated occurrence of main fall and periodic caving. Mohr-Coulomb Failure criteria along with a simplified strain-softening (MCSS) model was used to study the failure and caving mechanism. Salamon’s compaction model was used to simulate compaction and resultant stress recovery in the goaf material. Comparison of the model findings was done in terms of load on supports, abutment stress, and convergence, apart from the stress redistribution and failure mechanism. The load transfer mechanism of the soft overburden was also studied for an overall understanding of the strata behavior in such workings.

中文翻译：

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软覆层对地层及支护行为影响的围柱脱柱数值模拟研究

本研究的重点是在覆盖层卸料的大量碎片软覆盖的恒载条件影响下的Bord and Pillar除柱工作中的地层控制问题。它报告了在印度地质采矿条件下通过 FLAC 2D 软件工作的矿山建模。将某实际矿山在软覆盖下工作的建模结果与完整覆盖层条件下的模拟结果进行比较，以评估软覆盖层对除柱作业的影响。建模工作涉及地层的渐进式崩落和循环采空区充填，在模型模拟的主崩落和周期性崩落之后。Mohr-Coulomb 失效标准以及简化的应变软化 (MCSS) 模型用于研究失效和崩落机制。Salamon 的压实模型用于模拟采空区材料中的压实和由此产生的应力恢复。除了应力重新分布和破坏机制外，还根据支撑载荷、桥台应力和收敛性对模型结果进行了比较。还研究了软覆盖层的载荷传递机制，以全面了解此类工作中的地层行为。