变基床系数条件下充填采煤工作面顶板力学机制分析

Mechanical Mechanism of Working Face Roof Under Variable Coefficient of Subgrade Reaction in Filling Mining

为指导充填开采及工作面顶板控制措施提供理论依据,以榆阳煤矿风积砂似膏体充填开采为工程背景,考虑了工作面前方煤体破碎区基床系数为非恒定常数,同时,考虑了充填体基床系数随龄期增长而变化特征,建立了工作面顶板变基床系数弹性地基梁模型,利用有限差分原理对该模型进行计算,分析了顶板的挠度和弯矩分布规律,并提出了应对工作面顶板冒顶的防控措施。研究结果表明:顶板挠度在待充区上方最大,在控顶区上方最小,并随充填体基床系数的增加而降低;顶板弯矩在控顶区和待充区范围内变化剧烈,易造成顶板弯剪破坏。

To provide theoretical basis for guiding filling mining and roof control measures of working face,based on the engineering background of wind-blown sand paste filling mining in Yuyang Coal Mine,the foundation bed coefficient of the broken coal body area in front of the working face is considered to be an unsteady constant.At the same time,considering the changing characteristics of the foundation bed coefficient of backfill body with the age,the elastic foundation beam model with variable foundation bed coefficient of roof of working face is established.It is calculated by finite difference method and the distribution laws of roof deformation and bending moment were analyzed.In addition,the prevention and control measures to cope with the failure of the roof caving were proposed.The results show that the maximum deflection of roof is above the area waiting for filling,and the minimum one is above roof-control area,and it decreased with the increase of the variable coefficient of subgrade reaction.It was easy to cause bending shear failure of roof because bending moment was varied violently in the range of roof-control area and waiting for filling area.