切顶条件下“煤柱-充填体”协同承载性能及巷道稳定性分析

Analysis on Synergistic Bearing Performance and Roadway Stability of Coal Pillar-Filling Body Under Roof Cutting Condition

为了分析在切顶条件下不同“煤柱-充填体”支护对巷道围岩稳定性的影响,以某矿1226综采工作面运输巷为研究背景,通过理论分析与数值模拟相结合的方法,对切顶条件下应力转移过程和不同“煤柱-充填体”支护时垂直应力变化规律展开研究。研究结果表明:“煤柱-充填体”支护条件下,切顶时运输巷实体煤侧巷帮的垂直应力相对于未切顶时降低了9.5%,护巷煤柱侧巷帮的垂直应力降低了45%,运输巷两帮水平变形和巷旁支护压缩变形分别降低了21%和30.8%,即利用切顶卸压技术可以实现运输巷围岩应力及变形的双重优化,有利于运输巷围岩的长期稳定;巷旁支护垂直应力是影响巷道围岩稳定的主控因素,巷旁支护垂直应力平均降低速率随着充填强度的增加呈线性增加趋势,最大为5.8%,巷旁支护垂直应力平均降低速率随着煤柱宽度的增大呈先增后降趋势,最大为13.6%;根据“煤柱-充填体”协同承载性能变化对巷旁支护垂直应力的影响规律,拟合了不同煤柱宽度和充填体强度与巷旁支护垂直应力之间的函数关系式。在切顶条件下,留设护巷煤柱宽度为7.5 m、充填体强度为6.5 MPa时,对巷道围岩稳定的控制效果较好。

In order to analyze the influences of different“coal pillar-filling body”supports on the stability of roadway surrounding rock under the condition of roof cutting,taking the transportation roadway of 1226 fully mechanized mining face in a mine as the research background,the stress transfer process under the condition of roof cutting and the variation law of vertical stress under different“coal pillar-filling body”supports were studied by combining theoretical analysis with numerical simulation.The research results show that under the condition of“coal pillar-filling body” support,the vertical stress of the solid coal side slope of the transportation roadway during roof cutting is reduced by 9.5%compared to that without roof cutting,the vertical stress of the coal pillar side slope of the protective roadway is reduced by 45%,and the horizontal deformation of the two sides of the transportation roadway and the compression deformation of the roadside support are reduced by 21%and 30.8%,respectively.This means that the use of roof cutting and pressure relief technology can achieve the double optimization of the stress and deformation of the surrounding rock of the transportation roadway,which is conducive to the long-term stability of the surrounding rock of the transportation roadway.The vertical stress of roadside support is the main controlling factor affecting the stability of roadway surrounding rock.The average reduction rate of vertical stress of roadside support increases linearly with the increase of filling strength,and the maximum is 5.8%.The average reduction rate of vertical stress of roadside support increases first and then decreases with the increase of coal pillar width,and the maximum is 13.6%.Acording to the influence of the change of“coal pillar-filling body” synergistic bearing performance on the vertical stress of roadside support,the functional relationships between different coal pillar widths and filling body strengths with the vertical stress of roadside support were fitted.Under the condition of roof cutting,the control effect of roadway surrounding rock stability is better when the coal pillar width is 7.5 m and the filling body strength is 6.5 MPa.