THM-coupled MPM for freezing and thawing published in IJNAMG

Thermo-hydro-mechanical coupled material point method for modeling freezing and thawing of porous media

Climate warming is speeding up permafrost thaw and the hazards that come with it, such as ground collapse and retrogressive thaw slumps. These involve phase change, strongly nonlinear mechanics and fluid-like deformation all at once.

We develop a thermo-hydro-mechanical coupled, single-point, three-phase MPM in which ice is treated as part of the solid skeleton alongside soil grains, with an ice-saturation-dependent Mohr–Coulomb model for the extra strength from ice cementation. A fractional-step semi-implicit algorithm keeps the method stable and efficient even for nearly incompressible fluids and very low permeability.

Benchmarks of frozen-inclusion thaw and talik closure and opening confirm that the method handles both conduction- and convection-dominated regimes, before it is applied to fully coupled THM problems.