软煤层钻孔稳定性的影响因素分析

Influencing Factor Analysis on Borehole Stability in Soft Coal Seam

针对处于软煤层中的钻孔变形破坏对瓦斯抽采效果的影响,以胡底煤业煤体力学参数为依据,基于煤体的弹塑性本构关系,采用FLAC^(3D)软件建立不同埋深、不同钻孔直径、不同侧压系数以及有无塞花管支护等条件下相关的钻孔模型,分析研究钻孔的破坏情况。结果表明:埋深越大、钻孔直径越大、侧压系数越大,钻孔的稳定性越差;与未支护的钻孔相比,采用塞花管支护能有效抑制钻孔围岩变形,保证钻孔的稳定性,提高瓦斯抽采效率。

Deformation and failure of boreholes in soft coal seams affect the effect of gas drainage.Based on the mechanical parameters and the elastoplastic constitutive relationship of the coal in Hudi Mine,FLAC^(3D) software is used to establish drilling models,in terms of buried depths,borehole diameters,lateral pressure coefficients,and perforated pipe supports,to analyze the damage of the boreholes.The results show that the larger the buried depths,borehole diameters,and lateral pressure coefficients are,the worse the borehole stability is.Compared with unsupported boreholes,the perforated pipe support can effectively restrain the deformation of the surrounding rock,ensure the borehole stability,and improve the gas drainage efficiency.