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.