Numerical model of laser spallation drilling of inhomogeneous rock⁎

Spallation of rock during laser drilling is dependent mainly on temperature on the surface, material properties and presence of discontinuities within the rock. A numerical model of laser spallation of heterogeneous granitic rock using the Finite Element(FE) method is presented. The developed model accounts for the presence of microcracks within the rock. Convective boundary conditions are also considered and the effect of propagation of these cracks on spallation is investigated. Temperature and stress profiles generated are discussed. The results indicate stress development on the surface of the rock and its effect on eventual rock fracture.