大倾角沿空留巷承载特性及控制研究

Study on Load-bearing Characteristics and Control of Gob-side Entry Retaining with a Large Dip

针对大倾角煤层开采沿空留巷采空区垮落矸石滚动下滑,刚性支护体往往会受到挤压、滑动等问题,采用数值模拟方法分析了大倾角工作面围岩的应力分布、塑性区范围及位移规律。结合理论计算,得出刚柔结合的支护体系更适用于大倾角工作面沿空留巷的结论,并结合工程实践对试验巷道进行监测。研究结果表明,大倾角工作面上部应力呈拱形分布,且随着煤层角度的增大,拱顶越向上端头移动,工作面上部应力释放区范围也越大,说明上端头应力可以得到及时释放,工作面顶板垂直位移具有非对称分区性,中、上部区域顶板垂直位移量远大于下部顶板垂直位移量;采用挡矸网及支柱刚柔结合的方法,对冒落矸石进行胶结充填,最终留巷效果显著,顶板上部位移量最大,为278 mm,钢筋网最终呈"C"字型,中部变形量最大,为343mm,巷道上帮锚索受力大于下帮锚索,最大值为24 MPa,监测数据表明,巷道稳定性良好,可满足实际工程的需要。

In view of the problems of gangues rolling down in goaf of gob-side entry retaining and rigid support body often subjected to extrusion and sliding in coal seam with a large dip,the stress distribution,the plastic zone and the displacement regular of the working face with a large dip were analyzed by numerical simulation.Combined with theoretical calculation,it is concluded that the rigid and flexible supporting system is more suitable for gob-side entry retaining in working face with a large dip.Then,the test roadway was monitored in combination with the engineering practice.The results show that the stress is distributed in an arch shape in the upper part of the working face with a large dip,and with the increase of the coal seam angle,the vault moves to the upper end,and the stress release area enlarges in the upper part of the working face,which indicates that the stress in the upper end can be released in time.The vertical displacement of the working face roof has asymmetric partitioning,and the vertical displacement of the middle and upper parts is much larger than that of the lower part.The method of rigid and flexible combination of retaining net and support has been adopted for cemented filling of caving gangue,and the final entry retaining effect is remarkable.The displacement of the upper part of the roof is the largest,which is 278 mm.The final shape of the steel mesh is"C"shape,and the largest deformation is in the middle,which is 343 mm.The stress of the upper side anchor cable is greater than that of the lower side anchor cable,and the maximum value is 24 MPa.The monitoring data shows that the roadway stability is controllable and can meet the needs of practical engineering.