松软突出煤层沿顶钻进提高钻进深度方法研究

Study on Method of Enhancing Drilling Depth in Soft Outbursting Coalbeds with Roof Drilling

为解决松软突出煤层钻孔过程中出现的钻孔变形、卡钻的难题,提出了沿顶钻进提高钻进深度的方法,建立了沿顶钻进力学模型,采用数值分析的方法对比钻孔开挖后,钻孔变形、应力以及钻孔周边塑性屈服范围变化情况,结果表明:沿顶钻进方法能够有效减少钻孔上方变形量和最大主应力,同时,钻孔周边的塑性屈服范围明显缩小。在工程应用中,应根据施工地点松软突出煤厚变化等情况设计沿顶钻进工艺方式,以提高钻孔深度。

In order to solve the problem that borehole deformation and easy sticking when drilling in the soft outburst seam,the method of enhancing drilling depth with roof drilling was proposed.The mechanics model of roof drilling was established.The deformation,stress,and the plastic yield range around borehole after drilling were comparison analyzed by the numerical methods.The results showed that the method could effectively reduce the deformation and maximum principal stress along the top of borehole, and the plastic yield range around borehole was reduced obviously.The roof drilling process should be designed based on the thickness changes of soft outbursting coalbeds in construction sites,so as to improve the drilling depth.