Research on rock breaking efficiency of rotary punching drilling rig

LIU Bo, NI Peng, TAN Xiao-gang, ZHANG Chao
(School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China)

Abstract: Aiming at the low efficiency of rock breaking in the process of rotary drilling, the force model of interaction between spherical drilling teeth and rock ,and the finite element model of rock breaking by rotary punching drilling were established, which based on rock mechanics theory and finite element theory. The nonlinear finite element analysis software LS-DYNA was used to simulate rotary punching under different parameters. During the drilling process, the variation curves of the depthof the drill teeth with time, and the volume and rockcrushing efficiency of the broken teeth with the rotational speed and frequency were obtained. The influence of rotating speed and frequency on rock breaking efficiency was analyzed. The results indicate that the impact of rotation speed on the bit penetration depth is not significant, rock breaking mainly occurs after the impact force is unloaded, when the rotation speed is 30 r/min~35 r/min and the frequency ranged 20 Hz~30 Hz, the rock breaking efficiency is relatively high, which can fully boost the energy utilization.It provides a basis of the rational design of drill bit and the selection of drilling parameters of rock drilling tools.
Key words: rotary punching drilling; drilling efficiency; rotation speed; impact frequency; LS-DYNA