磨砂射流轴向切顶技术工业试验及防冲效果分析

Industrial experiment and anti-impact effect of axial roof cutting technology with abrasive water jet

为实现厚顶顶板预卸压工程的安全、高效和经济性,开展了磨砂射流轴向切顶技术的工业试验,确定了该技术的主要技术参数,并通过分析钻孔窥视、观测压裂过程中相邻钻孔出水情况、统计压裂前后疏水孔的出水速度、微震监测和支架阻力等变化规律对压裂和防冲效果进行检验。研究结果表明,完成了割缝长度300 mm,深度250 mm,压裂半径10 m的工业试验,确定了割缝压力、作用时间、用砂量、压裂压力和压裂作用时间等主要技术参数。分析钻孔窥视、观测压裂过程中相邻钻孔出水情况和统计压裂前后疏水孔的出水速度变化情况,表明割缝和压裂效果良好。采用磨砂射流轴向切顶技术后,微震事件总能量、总频次和大能量微震事件、来压强度和来压步距明显降低或减少。现场结果表明,该技术可以提高厚硬顶板预卸压效果,防冲效果良好。

To achieve safe,efficient,and economical pre-pressure relief of thick roof,an industrial experiment of axial top-cutting technology with abrasive water jet was conducted.The main technical parameters of this technology were determined.The effects of fracturing and anti-impact were examined by analyzing borehole inspection,observing the water discharge from adjacent boreholes during fracturing,statistical analysis of water discharge speed from dewatering holes before and after fracturing,microseismic monitoring,and analyzing the resistance of supports.The research results show that:The industrial experiment achieved with a grooving length of 300 mm,a depth of 250 mm,and a fracturing radius of 10 m,determining the main technical parameters such as grooving pressure,action time,sand usage,fracturing pressure,and fracturing action time.Analysis of borehole inspection,observation of water discharge from adjacent boreholes during fracturing,and statistical analysis of the change in water discharge speed from dewatering holes before and after fracturing showed good grooving and fracturing effects.After adopting the axial top-cutting technology with abrasive water jet,the total energy and frequency of microseismic events,the number of high-energy microseismic events,the pressure intensity,and the pressure step distance were significantly reduced or decreased.Field results showed that this technology can improve the pre-pressure relief effect of thick and hard roof and has good anti-impact effect.