Development Trend and Technology of Coal Floor Grouting Reinforcement Drilling Construction

The coal floor grouting reinforcement was an effective method for water bursting, according to limitations of conventional drilling construction, the paper mainly introduced directional drilling technology, which had been applied in Zhaogu No. 1 Coal Mine, where six directional holes with total footage of 3 455 m, single- h ole footage more than 400 m were drilled, which was three times of conventional drilling borehole. Combined with testing experience, the paper pointed out the attentio n and several disadvantages, such as complex casing- section construction and buckling borehole trajectory which could reduce borehole completed ratio and drilling ef ficiency were discussed.Therefore, the paper introduced casing drilling and composite dillig, which could simplifty borehole structure, reduce the operating procedure, optimize borehole trajectory and reduce the construction risk.