基于钻孔过程监测的花岗岩钻进比能研究

为了探究钻进参数与岩石质量之间的相关性关系,并寻求一个能够定量描述岩体质量的参数,利用安装了DPM系统的SGZ-IIIA型取芯钻机对一块1.25 m×2.00 m×1.00 m的花岗岩进行了6次钻孔试验,对每个孔设置不同的推进压强和转速等参数(压强分为400 kPa、600 kPa、800 kPa三挡,转速分为128 r/min、200 r/min两档),根据钻进位移与钻进时间计算得出钻进速度。结果表明,对于同一种岩石,如果在钻进过程中,转速、扭矩、推进压力等钻进参数不同,那么钻进速度也会相应变化,无法仅利用钻进速度来定量描述岩体质量,无法发挥DPM的优势。通过理论分析与花岗岩试验结果可知,钻进耗能为1.11~1.83 kJ/cm~3,平均值为1.523 kJ/cm~3,基于能量守恒定律,引入钻进比能的概念,发现此参数与岩石物理力学强度参数相关性高,可以用来表征岩石质量,从而实现通过岩石钻进快速确定岩体质量。

Drilling process monitoring-based study on granite drilling specific energy

In order to explore the correlation between drilling parameters and rock quality and find out a parameter that can quantitatively describes the quality of the rock mass， a 1.25 m×2.00 m×1.00 m granite block is adopted for drilling test for 6 times with SGZ-IIIA core drilling rig installed with DPM system， and then different parameters of driving pressure， rotating speed， （the driving pressures are 400 kPa， 600 kPa， 800 kPa respectively and the rotating speeds are 128 r/min，200 r/min respectively）， are set for each drilling hole； for which the drilling speed is calculated in accordance with the drill-displacement and drill-time. The result shows that if the drilling parameters of the rotating speed， torque， driving pressure， etc. during the drilling process， the drilling speed can be accordingly changed for the same type of rock， thus the rock quality cannot be only quantitatively described with the drilling speed and then the advantage of DPM cannot be brought into play. It is known from both the theoretical analysis and test made on granite that the drilling energy consumption is 1.11～1.83 kJ/cm3 with the mean value of 1.523 kJ/cm3. Based on the energy conservation law， the concept of drilling specific energy is introduced into the study， and then it is found out that the correlation between this parameter and the parameter of mechanical strength of rock is high and can be used for characterizing the quality of rock， thus the advantage of quick determination of rock quality with drilling of rock can be exerted as well.