古汉山矿定向预裂爆破切顶卸压沿空留巷技术

Technology of pressure relief by roof cutting for directional-predetermined crack blasting in gob-side entry retaining in Guhanshan Mine

为消除开采形成的"弧形三角顶板"对沿空留巷造成的不利影响,根据古汉山煤矿17021工作面地质开采条件,基于切顶卸压沿空留巷技术原理,提出"超前加强支护+定向预裂爆破切顶+留巷补强支护"的新型切顶卸压沿空留巷技术工艺,并制定了针对工作面运输巷切顶卸压沿空留巷的实施方案,确定了煤层顶板深孔定向切缝爆破参数、超前巷及留巷支护形式与参数,并通过矿压观测,对成巷效果进行了评价。研究结果表明:采用该留巷新工艺,巷顶板支护完整、平均下沉量248 mm,两帮平均移近量350 mm,巷支护体平均支护压力37 MPa,达到沿空留巷的使用要求。

The pressure arch in overburden during coal mining usually has an adverse effect on gob-side entry retaining.This paper proposed a method to reduce the adverse effects of pressure arch for No.17021 mining face of Guhanshan coal mine.Based on the geological conditions of the No.17021 mining face,technology of pressure relief by roof cutting in gob-side entry retaining was improved.The new technology combined the technology of front reinforcement support,directional-predetermined crack blasting,and reinforcement of gob side entry retaining.The implementation scheme was then conducted and applied in the haulage gateway.This scheme contained parameters of directional cutting seam blasting and support methods and its parameters of the front roadway and gob-side entry.The specification of gob-side entry was evaluated through mine pressure measurements.The results showed that average subsidence of the gob-side entry was 248 mm,the average displacement at the two sides was 350 mm,and the average support resistance was 37 MPa,which indicated a satisfaction of the usage requirement for gob-side entry.