基于FLAC3D的钻孔扩孔前后应力分布特征研究

Study on stress distribution characteristics before and after borehole reaming based on FLAC3D

煤层的钻孔成孔技术一直是煤矿瓦斯抽采的重要内容。本文以新景矿井下钻孔为研究对象,利用FLAC3D技术模拟分析钻孔扩孔前后钻孔周边的应力分布特征,分析了顺层钻孔和穿层钻孔扩孔前后应力分布的规律和钻孔有效卸压的影响范围。结果表明,随着钻孔的施工,钻孔周边应力释放形成明显的应力区,钻孔扩孔后,顺层钻孔的有效卸压范围由0.8 m扩大至4 m,穿层钻孔的有效卸压范围由0.6 m扩大至3.8 m,有效提高了煤层的抽采效果。

The drilling technology of coal seam has always been an important part of coal mine gas extraction.In this paper,the borehole in Xinjing Mine is taken as the research object,and the stress distribution characteristics around the borehole before and after reaming are simulated and analyzed by FLAC3D technology.The stress distribution law before and after reaming of bedding borehole and cross-layer borehole and the influence range of effective pressure relief of borehole are analyzed.The results show that with the construction of the borehole,the stress release around the borehole forms an obvious stress zone.After the borehole is reaming,the effective pressure relief range of the bedding borehole is expanded from 0.8 m to 4 m,and the effective pressure relief range of the cross-layer borehole is expanded from 0.6 m to 3.8 m,which effectively improves the extraction effect of the coal seam.