基于巨厚岩层-煤柱协同变形的煤柱稳定性

采前煤柱稳定性研究是工作面冲击危险性评估和开采方案设计的关键。以山东某矿深井巨厚砾岩条件工作面开采遗留煤柱为背景，采用案例调研、理论分析、数值模拟和工程实践等方法，对巨厚岩层-煤柱协同变形机制及其煤柱稳定性进行了研究，建立了巨厚岩层-煤柱协同变形的简化力学模型，探讨了引起煤柱变形的主要应力来源和变形形式，推导了在协同变形条件下煤柱的应力-应变关系。以此为基础，综合煤柱煤体应力、围岩稳定性和变形特征等条件，提出了煤柱整体失稳的力学判据。研究结果表明：巨厚岩层-煤柱失稳诱发冲击与煤柱的位置、尺寸和上覆岩层运动或变形关系密切，上覆岩层运动或变形是诱发煤柱失稳的动力因素；巨厚岩层-煤柱的变形主要包括受集中力F压迫的协同挠曲压缩变形和受集中力G作用的重力沉降变形，二者保持内在协调性；巨厚岩层下煤柱整体失稳的工程判据为煤柱煤体平均支承应力p超过其平均极限支承强度Rc（p≥Rc）；评估得到遗留的50 m煤柱具有强冲击危险性，并通过优化开采设计，取得了良好的效果。该研究成果对相似条件煤柱留设及其稳定性分析具有参考意义。

Stability of coal pillar on the basis of the co-deformation of thick rock strata and coal pillar

It is essential to assess the stability of coal pillar before mining for the evaluation of its rockburst risk and determination of mining schemes. Based on the geological conditions of a deep coal mine in Shandong province, China, these methods including in-situ case study, theoretical analysis, numerical simulation and engineering practice were adopted to evaluate the stability of the coal pillar with thick conglomerate upper strata. The deformation of conglomerate strata and coal pillar was analysed on the basis of a simplified mechanical model. We investigated the primary source of stress that caused coal pillar deformation and its deformation form, and obtained the stress-strain curve of coal pillar. Then, by considering the stress in coal pillar, surrounding rock stability and deformation, a mechanical criterion of coal pillar failure was proposed. It indicates that the location and size of a coal pillar, as well as the deformation of conglomerate upper strata, have significant impacts on the failure of coal pillar. The deformation of upper strata results in dynamic loading on the coal pillar. The deformation of coal pillar mainly includes collaborative deflection compression deformation induced by the concentration load F and the gravity settlement deformation caused by the concentration load G. The coal pillar failures when the supporting stress (p) is greater than its ultimate strength (Rc). It is found that the coal pillar with 50 m width has a high risk of rockburst, the risk decreased by optimising the mining scheme and achieved good effects. The results of this study are of significance for the analysis of the stability of coal pillar with similar conditions.