巷道底臌问题是影响深部煤矿安全生产的重大技术问题之一，底板锚固是治理底臌的有效方法，小孔径锚固孔是巷道底板锚固合理三径匹配的关键要素。钻进巷道底板小孔径锚固孔时存在排渣困难、孔壁局部破坏、钻孔深度小等瓶颈问题。项目依靠自主研发的钻头、排渣钻杆组成的钻进系统，研究深井巷道底板小孔径锚固孔钻进生成的“液渣混合流”特征及流态，建立复合应力作用下“液渣混合流”运移特征理论模型，揭示小孔内“液渣混合流”螺旋导升机制；构建下向小孔径锚固孔内自修复壳体物理力学参数与孔壁稳定性关系模型，厘清深井巷道底板小孔径锚固孔失稳与自修复原理；为深井巷道底板高质量小孔径锚固孔钻进提供理论基础。

Floor heave is one of the major technical problems for deep coal mine safety production, floor bolting is an effective way to control it, small diameter anchorage hole is the key factor of resonable "three diameters matching" for roadway floor bolting. There are some bottleneck problems when drilling small diameter anchorage holes, such as difficulty in deslagging, hole wall local failure and small drilling depth. Based on the domestically developed drilling system which consists of drill bit and deslagging drill pipes, the objects of this project are as follows: to study the characteristics and flow patterns of "liquid-cuttings mixed flow" when drilling small diameter anchorage holes in deep coal mine roadway floor, establish the transportation theoretical model of "liquid-cuttings mixed flow" in compound stress field and reveal the spiral guiding-lifting mechanism of "liquid-cuttings mixed flow" in the small diameter anchorage hole; to construct the relationship model between physical and mechanics parameters of self-repair shell and hole wall stability and clarify the mechanism of anchorage hole instability and self-repair of small diameter anchorage hole in deep coal mine roadway floor; to provide theoretical basis for drilling high quality small diameter anchorage holes in deep coal mine roadway floor.