In order to study the pressure changes and support failure in mining face under concentrated coal pillar in shallow coal seam, the concentrated coal pillar in 30105 working face of Nan Liang Coal Mine was selected as the research object. In this study, the mechanism of dynamic mine pressure in mining face under concentrated coal pillar was investigated through multiple simulation experiments, numerical simulations, and theoretical analysis. The results of similar simulation experiment indicate that the dynamic mine pressure occurred at 25 m under the concentrated coal pillar and 7 m beyond the coal pillar. The strata roof was observed with sliding down, resulting in collapse and severe fractures commonly seen in rock column. The overlying strata caused the overall subsidence and collapse synchronously, resulting in the sudden increase of the resistance of the support in the working face, and the dynamic load coefficients reach 3.4 and 3.5. The theoretical analysis indicates that the two hard strata in the overlying strata of 3⁻¹ coal meet the theoretical criterion of the combined key strata with the concentrated coal pillar of 2⁻² coal in the weak interlayer of the combined key strata. The combined key strata bear the load of the whole overlying strata. The sliding instability featured with the rock column-type fracture located in the combined key strata is considered as the primary trigger of the abnormal resistance of the support and the dynamic mine pressure in the mining face under the concentrated coal pillar. The dynamic pressure model of “combination key strata—immediate roof-support” was established, along with the dynamic load coefficient calculation related to the rock column-type fracture and instability. The characteristics of dynamic load coefficient of the rock column-type fracture and instability under different overlying rock structure conditions were analyzed, providing references and insights into mining under similar geographic conditions.

中文翻译：

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浅埋多煤层组合关键层岩柱失稳过程中动压力机制研究

为了研究浅层煤层集中煤柱下采煤工作面压力变化及支护破坏，以南凉煤矿30105工作面集中煤柱为研究对象。通过多次模拟实验，数值模拟和理论分析，研究了浓煤柱下采煤工作面动压的机理。相似的模拟实验结果表明，矿井动压发生在浓煤柱下25 m处，煤柱外7 m处。观察到地层屋顶滑落，导致坍塌和岩石柱中常见的严重裂缝。上覆地层引起整体沉降并同步塌陷，导致工作面中支撑的阻力突然增加，动态载荷系数达到3.4和3.5。理论分析表明，上覆地层3中的两个硬地层^-1煤满足2 ^-2的浓煤柱组合关键层的理论标准组合键层弱夹层中的煤。组合的关键层承担了整个上覆层的负荷。位于组合键层中的岩柱型裂缝所具有的滑动失稳被认为是支护异常阻力和集中煤柱下采煤工作面动压的主要触发因素。建立了“组合关键层-立即顶板支护”动压模型，并建立了与岩柱型裂缝和失稳有关的动载系数计算方法。分析了不同覆岩结构条件下岩柱型裂缝的动载荷系数和失稳特征，为相似地理条件下的开采提供了参考和见识。