薄煤层上行开采顶板巷道活动规律及支护

小河嘴煤矿2016(24)工作面为201采区24煤层首采面,24煤层厚度为0.3~0.75 m,厚度不稳定,瓦斯含量高,顶板为坚硬的中粒砂岩,在开采时伴有淋水,工作面顶板管理较为困难,月推进度仅为8~30 m,长期达不到设计产量,针对以上诸多问题,矿对上行开采进行了可行性研究,确定对顶板巷道的采用"锚杆+锚索+金属网+钢筋梯"的组合支护方式进行了支护。实践表明:上行开采顶板巷道活动可分为起始活动区、强烈活动期和活动衰退期;加强支护后两帮移近量明显减少,顶底板移近量减少不明显,说明巷道顶底板变形以底板变形为主,在锚网索联合支护作用下,使巷道顶板压力向巷道两侧深部转移,降低了两帮压力,利于巷道两帮稳定。上行开采顶板巷道不同支护区顶板绝对位移量不大,与煤层下沉量相接近,说明上行开采巷道顶板位移较为准确的反映了顶板覆岩的活动情况。

Roof tunnel activity law and support in thin seam ascending mining

Coalface 2016 （24） in Little hezui Coal Mine belongs to the first mining face of mining area 201. The thickness of coal seam 24 is about 0.3 to 0.75 meters. It has an unstable thickness with high gas. The roof is solid medium-grain sandstone and mining with water trickling. It is relatively difficult for the coalface roof management, only about 8 to 30 meters for face advance per month, unable to reach the design capacity over a long period of time. In view of the above, feasibility study for ascending mining is conducted in this paper. Then a combined support method of ＂anchor rod ~ anchor cable ＋ metal mesh ＋ steel ladder＂ is confirmed to apply for roof tunnel. The practice indicates that roof tunnel activity of as- cending mining can be divided into initial activity stage, drastic activity stage and activity decline stage. The deformation amount of roof tunnel＇s sides is obviously reduced after strengthened support; the de- formation amount of roof and floor is little reduced, it shows that deformation of roof and floor is mainly floor deformation. The roof pressure of tunnel is transferred to tunnel＇ s deeper sides by means of cable anchor combined support. That means the pressure of roof tunnel＇ s sides is reduced in favor of stable tunnel＇ s sides. The roof absolute displacement at different supporting area is not large in ascending mining roof tunnel. It＇ s very close to the amount of seam sinkage. It indicates that roof movement of ascending mining tunnel exactly represents the activity situation of roof overburden.