近距离房采煤柱下回采巷道失稳机理数值模拟研究

Numerical simulation on mining roadway instability mechanism under proximity room mining pillars

近距离房采煤柱下长壁开采将受到工作面顶板动压和上覆煤柱集中应力的共同影响,导致工作面剧烈来压从而引发回采巷道失稳事故。针对神东矿区大柳塔矿22202工作面潜在的巷道失稳事故问题,采用数值模拟研究了房采煤柱下长壁开采顶板的应力演化及运动规律,分析了回采巷道围岩的应力和变形特征。研究结果表明,工作面进入房采煤柱下方后,支承应力峰值点超前工作面距离会显著减小,造成超前支承峰值和工作面的顶板力叠加,在顶板来压和叠加应力共同作用下将引发巷道失稳事故;在房采煤柱采空区边缘前后20m范围内顶板运动和应力分布不稳定,巷道失稳事故发生的规律性差;远离采空区边缘60m后,顶板来压周期性明显,巷道失稳事故会周期性地发生。

The longwall mining under the room pillars is affected by both the active mining induced stress and upper pillars＇ concentrated stress, leading to instability accidents of roadway due to the severe roof pressure. Based on the issues of possible instability accidents of roadway in No. 22202 working face in Daliuta Coal Mine, numerical simulation were applied to study the mechanism of mining - induced stress evolution and instability accidents. The result shows that with working face under the coal pillars, the advance distance of bearing pressures＇ peak point will reduce significantly, resulting in the superposition of roof stress and the bearing peak stress. Roof weighting and the superimposed stress contribute to instability accidents of roadway. In the 20m range of the front and back of the edge of the coal pillars, instability of roof movement and stress causes no apparent regularity. With the working face is over 60m from the edge of mining gob, the instability accidents will happen periodically because of the obvious periodical roof pressure.