德顺矿煤柱留巷水力压裂弱化顶板技术研究

Study on Roof Weakening Technology of Coal Pillar Retaining Roadway by Hydraulic Fracturing in Deshun Coal Mine

为了在德顺煤业11106工作面开展煤柱留巷工程,采取水力压裂卸压技术抑制围岩变形,通过UDEC软件数值模拟影响卸压效果的因素——压裂次数和压裂位置。模拟结果发现:分段压裂距离越大,则压裂次数越少,切顶卸压效果越不理想,分段压裂距离最好小于4 m;在上区段工作面采空区侧布置压裂钻孔时,煤柱应力下降幅度达到15.1%.现场试验发现:压裂试验区巷道比非压裂试验区的巷道变形稳定期减小32.8%,两帮移近量下降达45.5%,顶底板移近量下降达63.1%,显著降低了煤柱留巷围岩变形量,卸压效果明显。

In order to carry out coal pillar roadway retention project in 11106 working face of Deshun Coal Mine,hydraulic fracturing pressure relief technology is adopted to suppress surrounding rock deformation.The factors affecting pressure relief effect——fracturing frequency and fracturing position are numerically simulated by UDEC software.The simulation results show that the larger the stage fracturing distance is the fewer the fracturing times and the less ideal the top cutting pressure relief effect.The stage fracturing distance is not suitable to be too long,preferably less than 4 m.When fracturing boreholes are arranged on the goaf side of the upper working face,the coal pillar stress drops most obviously with a decrease of 15.1%.Field tests show that the deformation of roadway in the fracturing test area decreases by 32.8%,the displacement of two sides decreases by 45.5%,and the displacement of roof and floor decreases by 63.1%in the stable period compared with that in the non-fracturing test area,which significantly reduces the deformation of surrounding rock in the coal pillar retaining roadway,and the pressure relief effect is obvious.