Detection of rock joints on the basis of drilling parameters

In geotechnical engineering, rock joints are the key factor in determining the stability of rock. Quickly and accurately identifying the joints in the rock has always been a concern in geotechnical research. A drilling experiment was designed for jointed rock with joint spacings of 5 cm, 10 cm, 20 cm and 30 cm, and a high-precision drilling parameter acquisition device was used to collect the drilling parameters. The response patterns of the rock joint spacing of the rock and the passive drilling parameters, rotation pressure and penetration velocity were investigated. The Kalman filter and moving average filter were used to process the raw data. Moreover, an algorithm for detecting the position of a rock joint was proposed. The results show that when the drill bit of the hammer rotary drilling rig passes through the position of the rock joint surface, the passive drilling parameters change abruptly, thus generating phenomena such as "velocity peaks" and "pressure valleys". The average relative errors of the joint detection algorithm based on the penetration velocity and rotation pressure were calculated to be 8.99% and 4.69%, respectively. Finally, It is more effective in identifying rock joint faces with spacing greater than 10 cm, the relative error of joint position detection based on the rotation pressure criterion was 0.46%, and the relative error of joint position detection based on the penetration velocity criterion was 0.48%.