大柳塔煤矿52607工作面柔模混凝土沿空掘巷技术可行性分析

Feasibility analysis of gob-side entry driving technology with flexible molded concrete in 52607 working face in Daliuta Coal Mine

针对厚煤层工作面采用柔模混凝土沿空留巷技术时,复用巷道围岩变形量大、修整作业量大、围岩稳定性较差等问题,提出采用柔模混凝土沿空掘巷配合切顶卸压技术,并通过理论计算和数值模拟分析了该技术在52607工作面的可行性,结果表明:当柔模混凝土墙体厚1.2 m、高4.3 m时,由覆岩自重作用在墙体垂直及水平方向的最大载荷分别为5740.36、101.20 kN/m^(2),均大幅低于墙体综合承载力,安全系数达2.25;同时考虑矸石冒落对墙体造成的侧压影响得出抗滑系数为31.56,远大于标准值;当52607工作面回采时,滞后工作面的墙体塑性区分布均位于顶端和底端,影响范围较小,最大仅0.74 m;超前工作面时,其超前支撑压力峰值位于工作面前方10 m处,为10.24 MPa,墙体内的应力峰值位于巷道侧底部,最高为9.25 MPa,运输巷的顶底板和两帮变形量最大分别为107.2、69.4 mm,均处于合理范围内,表明沿空掘巷技术在52607工作面和52号煤层类似地质条件下的应用具有一定可行性。

In response to the problems of large deformation of surrounding rock,large amount of trimming work,and poor stability of surrounding rock when using gob-side entry retaining technology with flexible formwork concrete for thick coal seam working face,it was proposed to adopt flexible formwork concrete gob-side entry driving with roof cutting and pressure relief technology.The feasibility of this technology in 52607 working face was analyzed through theoretical calculation and numerical simulation.The results showed that when the flexible formwork concrete wall was 1.2 m thick and 4.3 m high,the maximum load acting on the wall in the vertical and horizontal directions by the overburden self-weight was 5740.36 kN/m^(2)and 101.20 kN/m^(2),respectively,which were significantly lower than the comprehensive bearing capacity of the wall,and the safety factor was 2.25;considering the lateral pressure caused by the collapse of gangue on the wall,the anti-slip coefficient was 31.56,which was much higher than the standard value;dring the mining of 52607 working face,the plastic zones of the wall lagging behind the working face were located at both the top and bottom,with a relatively small impact range and a maximum of only 0.74 m;When advancing the working face,the peak value of the advance support pressure was located 10 m in front of the working face,at 10.24 MPa,and the stress peak inside the wall was located at the bottom of the roadway side,with a maximum of 9.25 MPa.The maximum deformation value between the roof and floor and between the two sides of the transportation roadway was 107.2 mm and 69.4 mm,respectively,both within a reasonable range.The results indicated that the application of gob-side entry driving technology in similar geological conditions of the 52607 working face and the No.52 coal seam had certain feasibility.