To resolve the problem of top mine instability and the consequent ecological damage caused by different grades of ore deposits in the layered mining process, layered filling-pillar-mining-displacement method (LFPMD) is proposed using a potash mine as an example. Based on the operation principles of the tail salt filling system, the mechanical behaviours of the tail salt under initial tamping and overburden loading were obtained through compaction tests in the laboratory. In addition, the mining-filling mass ratio of tail salt was derived. Based on the mining geological conditions of a potash mine in Laos and the compaction characteristics of tail salt, a mechanical model of top control by tail salt and a numerical model of top control by the pillars were established to discuss the stability of the upper-layer top mine and the lower-layer top mine. It was found that when the elastic foundation coefficient of the tail salt is greater than 550 MN·m⁻³, and the width of the retained pillars is 10 m, stability of the upper layer and the lower layer can be guaranteed. The results revealed that the LFPMD method can ensure stability of the overburden in the stope and reduce environmental damage while treating tail salt underground.

中文翻译：

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尾盐充填材料压缩行为对钾盐矿顶板变形的影响

为解决分层开采过程中不同品位矿床造成的顶矿不稳定及随之而来的生态破坏问题，以钾盐矿为例，提出分层充填-柱-开采-位移法（LFPMD）。根据尾盐充填系统的工作原理，通过室内压实试验，得到了初夯和上覆荷载作用下尾盐的力学行为。此外，推导了尾盐的采填质量比。根据老挝某钾盐矿开采地质条件和尾盐压实特征，建立尾盐顶控力学模型和柱顶控数值模型，探讨上层稳定性顶矿和下层顶矿。^-3，保留柱宽度为10 m，可以保证上层和下层的稳定性。结果表明，LFPMD方法在处理地下尾盐的同时，可以保证采场覆盖层的稳定性，减少对环境的破坏。