College of Energy Engineering, Xi'an University of Science and Technology
Xiayukou Coal Mine of Shaanxi Coal Hancheng Mining Co Ltd
Shaanxi Coal Chemical Industry Technology Research Institute Co Ltd

近距离煤层开采时,上位煤层的遗留煤柱集中应力会对下位煤层邻近采空区的巷道掘进产生扰动影响。 针对下峪口煤矿 3#下煤层回采巷道掘进时产生的非对称变形破坏及支护困难等问题,结合现场地质条件,采用力学分析、数值模拟和现场试验的方法,探究 23306下 进风巷掘进期间产生的非对称变形机理,并提出合理的巷道支护参数及工艺,改善了巷道围岩条件。 研究结果表明:上位煤层遗留煤柱及本煤层邻近采空区的存在导致巷道围岩主应力方向及大小发生变化,而非均匀的应力分布致使巷道围岩塑性区呈现蝶形破坏,巷道顶板水平应力变化幅度大、剪切应力大,造成巷道顶板极度破碎,顶板至上覆采空区间全为塑性区分布,顶板两侧应力及塑性区的差异性分布是造成巷道非对称变形的主要原因;数值模拟得到煤柱内 X-Y,X-Z,Z-Z 方向的应力受本煤层邻近采空区的影响较大,巷道两侧应力大小不等,致使巷道产生非对称变形;根据巷道围岩的受力状态、工作面地质条件及支护成本,优化了巷道支护参数,现场应用效果良好。

Concentrated stress of the remaining coal pillars in the upper coal seam impacts gob-side en-tries driving process in the lower coal seam when both seams are close with each. This study aims at theproblems of asymmetric deformation failure and support difficulties during the entry-driving process of 3#lower coal seam in Xiayukou Coal Mine. Multiple tools including mechanical analysis, numerical simu-lation and field test were combined with geological conditions, the asymmetric deformation mechanismduring the entry-driving process of 23306 lower in-take airway was investigated, and reasonable supportparameters and technical process were proposed, which improved the surrounding rock conditions. Theresults showed that the direction and value of the principal stress of the surrounding rock varied due tothe existence of the remanent coal pillar in the upper coal seam and the neighboring goaf. The non-uni-form stress distribution produced a butterfly-shaped failure in the plastic zone of the surrounding rock.Due to the large variation of the horizontal stress and the large shear stress of the roof, the roof was ex-tremely cracked, and the whole area between the roof and the overlying goaf was plastic. The differentialdistribution of stress and plastic zone bilateral the roof was the main reason contributing to asymmetricdeformation of the roadway. Numerical simulation indicated intense impacting of neighboring goaf incurrent seam on the stress state along X-Y, X-Z and Z-Z directions in coal pillars, and the different stressvalues bilateral the entry resulted an asymmetric deformation. According to the stress state of the sur-rounding rock, the geological conditions of the working face and the support cost, the supportparameters were optimized, and the implementation in engineering field was satisfactory.

国家自然科学基金项目(52074209);陕西省自然科学基础研究计划联合基金项目(2021JLM-06)

1 现场概况
1.1 工程概况
1.2 巷道非对称变形破坏特征
1.3 巷道非对称破坏影响因素
1) 应力环境
2) 支护形式
3) 邻近采空区影响
2 巷道非对称变形力学机制分析
2.1 3#煤采空区底板力学模型建立
2.2 3#煤采空区底板应力状态求解
3 巷道非对称变形数值模拟
3.1 数值模型建立
3.2 数值模拟结果分析
4 巷道控制对策
4.1 巷道已有支护措施改进
4.2 支护参数优化设计
5 结 论