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Temperature variations in low permeable soil (e.g. clay) induce pore pressure, which is known as thermal pressurization. Previous research showed that thermal pressurization highly depends on thermal pressurization coefficient. This coefficient depends on the soil type and changes with temperature due to temperature dependency of thermal expansion coefficient of water. Thermal pressurization is often investigated through thermo-hydro-mechanical (THM) numerical modeling. THM process, with respect to thermal loading, has been examined in the literature to justify the field observations by incorporating advanced thermo-mechanical constitutive models. However, result of numerical simulations using advanced thermo-elastoplastic models still show some discrepancies with experimental and field observations. In this study, the assessment of thermal pressurization in Boom clay is scrutinized through employing a relatively simple while practical thermo-poroelastic finite element model with careful consideration of the temperature-dependent thermal, hydraulic, and mechanical properties of the medium and saturating fluid (i.e. water). The numerical model is carried out using COMSOL Multiphysics and the results of the numerical simulations are compared and validated with the ATLAS project, a large-scale experimental facility in Belgium. The results confirm that thermal and hydraulic coupling parameters are the key factors to change thermal pressurization.

Energy piles are one of the best candidates to harvest shallow geothermal energy. Continuing harvesting and rejecting thermal energy from/to the ground may permanently change the soil temperature and consequently, may lead to different soil resistance parameters. Therefore, careful prediction of soil temperature variation close to energy geostructures is needed. This paper investigates the various parameters of heat source and soil media on transient heat transport in unsaturated soils. Green’s function and the method of separation of variables are employed to analytically analyze the transient heat transfer in the vicinity of energy piles. Results indicate that although higher heat flux increases the soil temperature surrounding a heat source, it has negligible effect on thermal influence zone where the soil temperature varies. In contrast, higher thermal diffusivity results in lower soil temperature close to a heat source while it increases the thermal influence zone.