Multiphysics modeling of thermal cracks in multiphase porous materials

A thermo-hydro-mechanical crack phase-field model is developed to investigate initiation and propagation of fissures in multiphase porous media under thermal loading (e.g. Figure 1). While the coupled u-p w -d framework in [1] addressed water flow, deformation, and fracture in variably saturated media, subsequent studies have highlighted the significant influence of gaseous phases, especially under temperature variations [2]. Based on the poromechanics theory developed in [3–4], the present work introduces a computational framework that integrates heat, water, and gas transport with fracture processes, providing a robust tool for simulating coupled thermo-hydro-mechanical cracking in variably saturated porous systems. To validate the proposed model, several benchmark cases were carried out. First, the implemented framework was compared with the results of the Griphfith finite element code [5] in terms of phase- field solution and force–displacement response of a tensile solid mechanical test, showing a very good agreement (Figure 2). Then, validation for the thermo-mechanical implementation of the model was performed using a classical benchmark case [6–7], demonstrating consistent agreement between the numerical solution and the analytical one, Figure 3. Finally, a hydro-mechanical fracture problem was solved, in which the simulated vertical stress and pore-water pressure distributions during tensile fracture along a vertical sand column were compared with the reference results in [1], Figure 4. These benchmark studies confirm the accuracy and applicability of the proposed framework. Moreover, a simple thermal expansion simulation was conducted to further illustrate the model’s capability in capturing thermally induced crack initiation and propagation. Further validation tests in non- isothermal variably saturated soils are ongoing.