Numerical modelling of thermal drilling of rock by heating-cooling cycle

Abstract

This paper presents a numerical study on thermal drilling of rock. In this context, thermal drilling refers to the disintegration of rock surface material when exposed to a heat shock consisting of an intensive external thermal flux and consequent rapid cooling. An embedded discontinuity finite element approach is chosen for modelling the rock cracking due to the heating-cooling cycle. The underlining uncoupled thermo-mechanical problem is solved by an explicit time stepping scheme with mass scaling to increase the time critical time step. Numerical simulation of a heterogeneous rock sample under axisymmetric conditions demonstrate that the drilling by a rapid heating-cooling cycle is a feasible method at conditions where the bulk rock is at elevated temperatures.