Abstract: In order to improve the drilling efficiency and reduce tools wear， a new rock fragmentation method of shock disturbance was put forward. Based on the theory of Walsh， a crack model of the damage rock around the induced hole was established， the intrusive coefficient equations and intrusive resistance equations of the cone bit were deduced. The influences of crack density， the disturbance frequency on the elastic modulus， the rock crushing volume and the intrusive resistance were analyzed. Experimental results showed that the effective elastic modulus of rock decreases with the increase of crack density. Under the certain intrusion load， the depth of the penetration and the rock crushing volume increase continually with the increase of the disturbance frequency. The intrusive resistance of the cone bit decrease gradually with the increase of the disturbance frequency.

Key words: crack density, intrusion coefficient, intrusive resistance, disturbance frequency