Investigation of the tool-rock interaction using Drucker-Prager failure criterion

Mechanical rock breaking in different forms have found wide applications in the mining and civil engineering industry such as drilling, tunnelling and grinding. A detailed understanding of the tool-rock interaction is essential to achieve high efficiency in rock breaking and to optimize the cutting parameters. The finite element simulation of the tool-rock interaction remains a challenging task due to the complexity caused by the physical rock properties, the crack initiation and propagation, as well as the chip generation phenomenon. This study has implemented the Drucker-Prager constitutive model with an isotropic damage model in a finite element analysis to examine the rock failure modes, considering the interaction of cutting tool and the rock. The material parameters for the rock derive from the uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS) tests performed on rock specimens. This study includes an experimental program to examine the crack initiation, crack propagation and the chip generation in rock specimens. The results show the Drucker-Prager failure criterion with the calibrated material parameters and element sizes simulate closely the tool-rock interaction phenomenon. The mesh size imposes a great effect on the parameter selection of the rock model, particularly for the fully damaged plastic strain value. This study leads to an enhanced understanding of rock breaking mechanisms in the mechanical excavation, and provides the basis to improve the rock excavation machine design.