切顶卸压沿空留巷技术研究与实践

Study on gob-side entry retaining technology by using roof cutting and pressure relief and its practice

针对常规留设煤柱开采方法所带来的煤炭资源采出率低、万吨掘进率高、采空区发火、瓦斯治理困难等问题,结合新桥煤矿2304工作面煤层顶底板条件,利用双向聚能爆破技术提前预裂爆破,使得巷道顶板按照设定方向张拉预裂成缝,工作面推进过后采空区沿缝隙垮落,减小了对留巷段的应力,采用"恒阻大变形锚索+单体支柱+液压支架"的支护形成巷道上方基本顶岩梁的支撑,采用"29U型钢点柱+钢筋网"隔断采空区和留巷区,实现了新桥煤矿首个切顶卸压沿空留巷工作面的成功实施。切顶卸压沿空留巷技术解决了新桥煤矿沿空掘巷顶板难控制、生产接替紧张的难题,同时提高了矿井采出率、降低了矿井生产成本。

Aimed at the difficult problems of low recovery rate of coal resources,the high driving rate of ten thousand tons,the goaf ignition,the gas control etc of conventional mining method,combined with coal seam roof and floor conditions on 2304 working face in Xinqiao Coal Mine,two-way shaped presplit blasting was used ro realize blastingin advance,to make sure the direction of formed fracture in roadway roof in accordance with the designed direction,after the working face driving,the roof gob became caving along the fractures,which has reduced the stress to the retaining roadway. The suupporting methods were used,combining with constant resistance large deformation anchor ＋ single body prop ＋ hydraulic support,and ＂ 29 U type steel point column ＋ steel net＂ was used to separate the gob and roadway retaining area,the application of these method has achieved the success of the firsrt roof cutting and pressure relief working face with gob-side entry retaining. The application of gob side entry retaining technique with roof cutting and pressure relief,has solved the difficult problem of controlling the roof of the roadway along the goaf of the Xinqiao Coal Mine,and the tension of production replacing;meanwhile,the recovery rate of the mine was improved,and the production cost of mine was reduced.