In the framework of hypoplasticity, the non isothermal behaviour has not gained much attention. Furthermore, neither thermally induced compression of clays nor thermal strain rate dependency is described by existing hypoplastic models. This work is devoted to the extension of the visco-hypoplastic model formulation to present a unified model for both thermal and viscous strains in clays. The model predictions are assessed through comparisons with existing laboratory experiments on two clays with measurements of both isothermal/mechanical creep and thermally induced creep strains. A thorough calibration scheme of the material parameters is shown and demonstrated based on laboratory

The effect of temperature on the mechanical behaviour of clay-based geomaterials is relevant in several geotechnical applications. This research uses combined SAXS/WAXS measurements to monitor nano-scale changes induced in the clay basal distances of several fine-grained natural soils in their saturated state by temperature variations. The results show that intra-particle changes upon heating in saturated samples do not play a major role in the macroscopic thermo-mechanical response of clay within the temperature range considered for most thermal applications, and this is independent by clay mineralogy.

- This work mixes encapsulated Phase Change Materials (EPCMs), graphite and recycled glass fines, aiming to develop green backfill materials with excellent thermal properties. - The heat capacity and thermal conductivity of the mixtures with different fractions of the components are measured in a laboratory. - The measured data agree with simulated results. Better thermal properties can be achieved with specific fractions of components, and the findings could help geothermal systems design for better energy utilisation.

Drilling in soft rocks. Comparison with indentation and cutting studies

It seems that there is an optimal calcification content among higher cementation levels that would be sufficient for creating more efficient bonds in the soil matrix, which rapidly elevates the TC. Neither the conventional soil models nor the theoretical or empirical equations from the literature can accurately predict the results of the dry state thermal conductivity. Hence, more investigation on thermal conductivity in the dry state, especially on the higher cementation level impact, is needed to de-duct a good prediction for different cases of MICP-treated sands