Study on long-distance fast advance drilling technology strategy and supporting equipment in coal mine roadway tunneling

With the gradual increase in the depth of coal resource extraction in our country, geological conditions and surrounding rock environment are becoming increasingly complex. The degree of water damage, gas and other disasters faced during excavation is increasing. As a necessary channel for exploring and controlling disasters, advanced drilling is an urgent need for long-distance and rapid advanced drilling technology due to the increasingly serious mining imbalance. Firstly, based on the relevant safety regulations of coal mines and the excavation conditions of coal mine tunnels, the demand for advanced drilling in tunnel excavation was analyzed. Then, based on the essence of “long-distance rapid advance drilling”, three key technical problems of “insufficient drilling depth in complex formations”, “severe drilling deviation”, and “low drilling efficiency in hard rock” in current drilling technology were analyzed. Secondly, a summary study was conducted on three key technical issues, including “complex pipe following drilling technology”, “drilling deviation prevention technology”, and “efficient hard rock drilling technology”. In response to the difficulty of drilling holes in complex formations due to borehole collapse, different hole protection technologies and supporting equipment were summarized, and their applicability to different working conditions was analyzed. A complete set of bottom driven fast pipe following equipment was developed, which extended the drilling depth in complex formations by 2-3 times; In response to the problem of preventing deviation in advanced drilling under rotary drilling conditions, the mechanical mechanism of deviation in rotary drilling was analyzed. The principle, structure, and performance of anti deviation drilling tools were analyzed from the perspective of suppressing drilling inclination and azimuth angles. A single action straight drilling tool was developed that can simultaneously stabilize inclination and azimuth angles. During the drilling process, the outer pipe did not rotate, and the core shaft drove the drill bit to rotate and break the rock, On site experiments have shown that it is possible to simultaneously control the tilt angle and azimuth deviation rate to 1.5 (°)/100 m; In response to the problems of low efficiency and fast wear of rock breaking tools in advanced drilling of hard rock tunnels, this paper analyzes the efficient rock breaking mechanisms of different hard rocks and comprehensively elaborates on the corresponding rock breaking tools and supporting technologies and equipment. A small diameter stable pressure and speed increasing drilling tool based on active vibration suppression principle has been developed, which can increase the speed by 1.5 to 2 times in coal bearing limestone formations with f (rock firmness coefficient) coefficient of 12. Finally, in response to the three key requirements of advanced drilling, namely “hole protection”, “deviation prevention”, and “speed improvement”, the development direction of corresponding process equipment is proposed.