Numerical study of the inﬂuence of hydrostatic and conﬁning pressure on percussive drilling of hard rock
Research output: Contribution to journal › Article › Scientific › peer-review
|Number of pages||9|
|Journal||Computers and Geotechnics|
|Publication status||Published - 2016|
|Publication type||A1 Journal article-refereed|
fracture in this approach is modeled with a damage-viscoplasticity model accounting for the main fracture types in the bit-rock interaction as well as the strain-rate effects. The model was calibrated for Kuru grey granite in the unconﬁned case. In the simulations of single impact with a multiple-button bit both hydrostatic and conﬁning pressures were applied at different levels up to 100 MPa and the results were compared to the case with no pressure. The simulations show that at this pressure level the volume of the failed elements was 38% in case of hydrostatic pressure and 56% in case of conﬁning pressure of the volume in the pressure free case. The same ﬁgures apply to corresponding rates of penetration. The cause of this reduction in the material removal or the rate of penetration is the compressive stress state, of either pressure type tested, which effectively suppresses tensile and shear fractures.