Numerical Modeling of Time-Dependent Thermally Induced Excess Pore Fluid Pressures in a Saturated Soil

Abstract

A temperature rise in soils is usually accompanied by an increase in excess pore fluid pressure due to the differential thermal expansion coefficients of the pore fluid and soil particles. To model the transient behavior of this thermally induced excess pore fluid pressure in geotechnical problems, a coupled thermohydro-mechanical (THM) formulation was employed in this study, which accounts for the nonlinear temperature-dependent behavior of both the soil permeability and the thermal expansion coefficient of the pore fluid. Numerical analyses of validation exercises (for which an analytical solution exists), as well as of existing triaxial and centrifuge heating tests on Kaolin clay, were carried out for this research. The obtained numerical results exhibited good agreement with the analytical solution and experimental measurements respectively, demonstrating good capabilities of the applied numerical facilities and providing insights into the mechanism behind the observed evolution of the thermally induced pore fluid pressure. The numerical results further highlighted the importance of accounting for the temperature-dependent nature of the soil permeability and the thermal expansion coefficient of the pore fluid, commonly ignored in geotechnical numerical analysis.