长壁工作面巷顶沿空掘巷围岩应力分析

镇城底矿工作面的回采巷道一条沿顶板掘进，一条沿底板掘进，相邻两工作面在端头搭接，沿底板掘进的巷道形成巷顶沿空掘巷。通过理论分析、相似模拟、数值模拟及现场实测对巷顶沿空掘巷围岩结构及应力环境进行了研究。得到如下结论：该巷道不受超前和固定支承压力影响，大结构下方的矸石垫层可起到能量和应力耗散的作用，避免了动载和冲击影响，应力低且稳定；岩层移动形成的垮落角对采空区应力大小和分布（尤其采空区边缘）有重要影响；垮落角越小，采空区应力越小，该巷道围岩应力越小，采空区恢复至原岩应力的距离越大；垮落角对岩体塑性区发育方向起控制和导向作用；该巷道围岩应力大幅低于原岩应力，卸压程度大；实测该巷道竖向和横向位移均比非沿空巷道小，即顶底板和两帮应力环境均得到改善。研究对维护具有冲击倾向的高应力巷道具有一定意义。

Investigation of stress of surrounding rock mass of gob-side entry under gob of a longwall panel

The gateroads on the sides of a longwall panel at Zhenchengdi Coal Mine are driven along the roof and floor, respectively, and thus the gateroad along the floor becomes the gob-side entry under a longwall gob. In this paper, theoretical analysis, physical modelling, numerical modelling and field observation are conducted to investigate structures and stress of surrounding rock mass of this gob-side gateroad. It is found that the gob-side entry is independent of the side and front abutment pressures. The caved rock cushion under the masonry beam structure can dissipate energy and stress for the gob-side entry, which prevents from dynamic and impact loads, providing the stable stress environment much lower than pre-mining stress. The angle of break developed due to strata movement has a significant effect on stress and distribution (especially on gob edge). The lower the angle of break is, the smaller the gob pressure and stress are around the entry, and the larger distance between the gob edge to the location where pre-mining pressure occurs. The angle of break has a dictating and guiding function for the plastic zone development. The stress of surrounding rock mass of gob-side entry is significantly lower than premining stress with the high destress degree. Both the roof to floor and rib to rib convergences are smaller than that of non-gob-side entry, which demonstrates that overall stress environment is improved. The study is of certain drawing significance for highly stressed burst-prone gateroads.