缓倾煤层沿空留巷煤柱宽度计算与分析方法

Calculation and Analysis Method for Coal Pillar Width of Retaining Roadway Along Goaf in Gently Inclined Coal Seams

为探究缓倾斜厚煤层沿空留巷窄煤柱的合理留设宽度计算方法,以义桥煤矿6#煤层回采巷为工程背景,基于力学分析建立了缓倾煤层沿空留巷护巷煤柱宽度计算模型,并通过数值模拟进行了数值验证和分析。结果表明:在缓倾斜煤岩层沿空留巷掘进过程中,煤岩层原有平衡状态被打破,沿空留巷窄煤柱主要采空区受堆积煤矸及浮煤侧压力和上覆岩体荷载产生的支承压力作用;煤柱合理留设宽度与邻近回采工作面在沿空留巷煤柱内产生的破碎区宽度、煤柱巷道侧锚杆的有效长度及煤层厚度和倾角密切相关,基于静力平衡条件,通过这些因素的综合分析可建立估算煤柱合理留设宽度计算模型;背景工况下煤柱宽度为4 m时,煤柱的安全性较高,可避免煤柱承载过大,减少巷道顶板拉伸破坏。

In order to explore the reasonable calculation method for the reserved width of narrow coal pillars with retaining the roadway along the goaf in gently inclined thick coal seams,taking the 6#coal seam mining roadway of Yiqiao Coal Mine as the engineering background,a calculation model for the width of protection roadway coal pillars with retaining the roadway along the goaf in gently inclined coal seams is established based on mechanical analysis.Numerical verification and analysis are conducted through numerical simulation.The results show that the original balance state of the coal and rock strata is broken during the excavation of retaining the roadway along the goaf in the gently inclined coal and rock strata,and the main goaf area of narrow coal pillars with retaining the roadway along the goaf is affected by the side pressure of accumulated coal gangue and floating coal and the abutment pressure generated by the load of overlying rock mass;The reasonable reserved width of coal pillars is closely related to the width of the fractured zone generated in the coal pillars of retaining the roadway along the goaf near the mining working face,the effective length of the side anchor bolt of the coal pillar roadway,and the thickness and inclination angle of the coal seam.Based on the comprehensive analysis of these factors under static equilibrium conditions,a calculation model for estimating the reasonable reserved width of coal pillars can be established;When the width of the coal pillar is 4 m under background engineering conditions,the safety of the coal pillar is relatively high,which can avoid excessive bearing capacity of the coal pillar and reduce the tensile failure of the roadway roof.