Pore fluid enhanced thermal spallation of rock: a numerical study

Thermal spallation of rock, i.e. the fragmentation of rock surface material under rapid external heating, is numerically studied here. A special emphasis is laid on the possibility that the fluid in the micropores of rock enhances the spallation due to rapid thermal expansion. For this end, a numerical model based on the embedded discontinuity finite element approach to rock fracture and an explicit scheme to solve the underlying thermo-mechanical problem is developed. The fluid trapped into the micropores is modelled as a material that can bear only volumetric compressive stresses. A thermal spallation problem of a rock sample under axisymmetry is simulated as a numerical example. According to the
simulations, the potential presence of the pore-fluid significantly boost the spallation events.