为了揭示浅埋近距离煤层工作面过平行煤柱开采动载传递特征及强矿压机理, 以榆家梁煤矿43207工作面为工程背景, 采用现场实测、物理模拟、理论分析相结合的方法, 研究了煤柱覆岩“倒梯形”结构随下部间隔岩层的运动及其载荷传递特征, 分析了超前支承压力和支架载荷的转化规律, 建立了“煤柱−间隔岩层台阶岩梁”耦合结构力学模型, 得出了强矿压瞬间和顶板切落稳定后的支架载荷计算公式。研究结果表明: 煤柱覆岩“倒梯形”结构的集中应力和载荷主要集中于煤柱后段, 后段集中载荷是导致工作面过煤柱强矿压的根源; 工作面进煤柱初期, 煤柱应力表现为双峰; 临近出煤柱时, 应力集中为单峰, 位于煤柱后段。工作面出煤柱4 m后, 煤柱后区的超前支承应力系数达到峰值6.00, 间隔层开始产生超前裂隙; 出煤柱5 m时发生强矿压, 煤柱应力下降43%。强矿压期间, 煤柱应力传递至煤柱下7 m层位(间隔岩层关键层中部)下降了39%, 表明顶板结构承担了相当大的载荷。基于间隔岩层台阶岩梁结构的理论计算, 得出强矿压瞬间的支架载荷计算公式, 按照煤柱平均应力计算得出支架载荷为22.9 MN/架, 按照强矿压时刻煤柱后段应力计算得出支架载荷为24.1 MN/架; 煤柱传递至支架的载荷仅为煤柱总载荷的12%~18%, 仍超过现场支架额定工作阻力9.2 MN/架。因此, 为防止压架, 支架额定工作阻力需达到15 MN/架, 或者对煤柱及间隔岩层结构进行处理, 以保证安全开采。研究结果可为类似条件工作面过平行煤柱开采提供参考。

In order to reveal the dynamic load transfer characteristics and strong ground pressure mechanism when passing through parallel coal pillars in shallow close-distance coal seams mining, field measurement, physical simulation and theoretical analysis were performed to study the movement and load transfer characteristics of the "coal pillar inverted trapezoidal" structure with the lower interval rock strata by taking the 43207 working face of Yujialiang Coal Mine as the engineering background. The transfor law of front abutment pressure and support load is obtained, and the coupling structural mechanics model of "coal pillar-interval step voussoir beam" is established. The calculation formula of support working resistance at the moment of strong ground pressure and after roof cutting were proposed. The results show that the concentrated stress and transfer load of the inverted trapezoidal overburden of coal pillar are mainly concentrated in the rear section of coal pillar, and the load in this area is the main cause of the strong ground pressure of working face when passing through the overlying coal pillar. At the early stage of working face entering the coal pillar, the stress of coal pillar is bimodal; when the working face is to pass coal pillar boundary, the stress concentration distribution is single-peaked, which is located in the back section of the coal pillar. When the working face is 4 m away from coal pillar, the front abutment pressure in the back area of coal pillar reaches the peak value of 6.00, and cracks appear in the interval strata. When the coal pillar is 5 m away from coal pillar, strong ground pressure occurs, and the stress of coal pillar decreases by 43%. During the period of strong ground pressure, the stress of coal pillar is transmitted to the overlying rock layer of 7 m above coal pillar(the middle of the key stratum of the interval strata), which is reduced by 39%, indicating that the roof structure bears a considerable load. Based on the theoretical calculation of the step voussoir beam structure of the interval strata, the calculation formula of the support load at the moment of strong ground pressure is obtained. According to the average stress of coal pillar, the support load is calculated to be 22.9 MN/frame. According to the stress of the rear section of coal pillar at the time of strong ground pressure, the support load is calculated to be 24.1 MN/frame. The load transmitted from coal pillar to the support is only 12%-18% of the total load of coal pillar, which still exceeds the rated working resistance of field support by 9.2 MN/frame. Therefore, to prevent support crushing, the rated working resistance of support needs to reach 15 MN/frame, or the coal pillar and the interval strata structure are treated to ensure safe mining.