Under the condition of close-distance double-thick coal seams’ mining, the serious strata behavior occurred in the lower retracement channel, which is affected by the double disturbance with upper coal-pillar static load and mining dynamic pressure. Field investigation, laboratory test, and numerical simulation were used to study the failure characteristics and stress distribution of N0381 retracement channel. The results show that the plastic failure and stress of the surrounding rock are obviously asymmetric; specifically, the closer the roof is to N0381 gob, the stronger the strata behavior is. In addition, when the upper coal pillar is in critical stable or stable state (), high stress concentration in the upper coal pillar is transmitted downward through floor rock so that two dangerous areas with severe strata behavior are formed in N0381 retracement channel. In view of this, a partition control strategy with “high-pressure water jet + asymmetric high-strength cable-beam net + three-hole anchor cable group + roof grouting” as the core is proposed to ensure the stability of the lower retracement channel. This study provides a reference for coal mines with similar production geological conditions.

中文翻译：

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近距离双厚煤层下回撤通道破坏机理与控制

在近距离双厚煤层开采的条件下，下回撤通道发生了严重的地层行为，受上部煤柱静载荷和动压双重干扰的影响。通过现场调查，实验室测试和数值模拟研究了N0381回撤通道的破坏特征和应力分布。结果表明，围岩的塑性破坏和应力明显不对称。具体而言，屋顶距离N0381采空区越近，地层特性越强。此外，当上部煤柱处于临界稳定或稳定状态时（），上部煤柱中的高应力集中通过底板岩石向下传播，从而在N0381回撤通道中形成了两个具有严重地层行为的危险区域。鉴于此，提出了以“高压喷水+不对称高强斜拉索网+三孔锚索群+顶棚注浆”为核心的分区控制策略，以确保下回撤通道的稳定性。 。该研究为具有相似生产地质条件的煤矿提供了参考。