基于冲击回转钻进的岩石强度随钻识别研究

Rock strength identification while drilling based on percussive rotary drilling

在隧道掘进施工过程中,数字化钻孔过程监测(drillingprocessmonitoring,简称DPM)系统能够实时快速地获取岩石强度参数,及时指导现场开挖和支护作业。为实时获取隧道开挖掌子面前方的围岩强度,基于搭载于气动冲击回转钻机上的数字化DPM系统地开展现场原位数字钻进试验。通过对钻孔全过程的推进压力、回转压力、冲击压力以及钻杆位移等钻进参数进行实时监测、记录和分析,得到了不同钻孔过程的钻进参数特征,据此对各钻孔过程进行识别,并采用DPM时间序列分析方法分离出纯钻进过程钻进参数,结果表明:纯钻进过程的钻进深度随钻进时间呈分段线性变化;钻机工作压力随钻进时间的变化相对恒定,其对不同钻速段的钻速变化影响有限;同时,钻进速度随岩石强度增加而减小,并建立了岩石强度关于钻进速度的指数关系模型,用以指导工程实践。

During tunnel excavation,the digital drilling process monitoring(DPM)system can quickly obtain rock strength parameters in real time,and guide on-site excavation and support operations in a timely manner.In order to obtain the surrounding rock strength in front of the tunnel face in real time,this study carried out the in situ digital drilling tests based on the digital drilling process monitoring(DPM)system mounted on the pneumatic percussion rotary drilling rig.Through the real-time monitoring,recording and analysis of the drilling parameters such as propulsion pressure,rotary pressure,impact pressure and drill pipe displacement in the whole drilling process,the characteristics of the drilling parameters in different drilling processes are obtained.On this basis,each drilling process is identified,and the drilling parameters of the pure drilling process are separated by using the DPM time series analysis method.The results show that the drilling depth of the pure drilling process changes linearly with the drilling time.The variation of working pressure of the drilling rig with the drilling time is relatively constant,and it has limited influence on the rate of penetration in different rate-of-penetration sections.Meanwhile,the rate of penetration decreases with the increase in rock strength,and an exponential relationship model between rock strength and rate of penetration is established to guide engineering practice.