瓦斯抽采钻孔封孔段稳定性分析与封孔技术

Stability Analysis and Sealing Technology of Gas Extraction Drilling Sealing Section

针对松软煤层瓦斯抽采顺层钻孔封孔段围岩稳定性差、易塌孔堵塞问题,以马军峪煤矿90107工作面为工程背景,研究了钻孔围岩塑性区半径及应力分布。采用数值模拟对钻孔围岩塑性区和应力场分布进行验证分析,结果表明,随着支护力逐渐提高,钻孔围岩塑性区半径逐渐减少且趋于稳定。因此,提出运用囊袋式注浆封孔技术,通过注浆压力减缓钻孔变形速度,确保钻孔稳定可用,进而提高瓦斯抽采浓度。

In view of the problems of poor stability and easy collapse and blockage of the surrounding rock in the sealing section of the boreholes for gas extraction in soft coal seams,the author studies the plastic zone radius and stress distribution of the borehole surrounding rock in the 90107 working face of Majunyu Colliery,verifies and analyzes the plastic zone and stress field distribution of the borehole surrounding rock through numerical simulation,whose results indicate that as the support force gradually increases,the radius of the plastic zone of the borehole surrounding rock gradually decreases and tends to stabilize.Therefore,the author proposes to use pocket grouting sealing technology to slow down the deformation speed of drilling through grouting pressure,which ensures the stability and availability of drilling,and thereby increases the concentration of gas extraction.