煤层钻孔的失稳破坏是一个非常复杂也是一个极其常见的问题,煤层钻孔的稳定性对煤层瓦斯抽采以及煤层注水都有着非常重要的意义。基于D-P准则和UDEC数值模拟的方法对钻孔失稳破坏进行研究,研究表明,随着节理密度的增大钻孔周围的剪切位移呈指数增加;钻孔首先在孔壁处发生拉伸破坏,随着煤体沿径向向深部转移,钻孔周围的煤体逐渐发生剪切破坏。 Unstable failure of coal seam drilling is a very complex and extremely common problem. The stability of coal seam drilling has very important meanings for coal seam gas drainage and coal seam water injection. Based on the DP criterion and the UDEC numerical simulation method, the instability of the borehole is studied. The results show that the shear displacement around the borehole increases exponentially with the increase of the joint density. As the coal moves radially to the deep, the coal around the borehole gradually undergoes shear failure.