Modelling the volume change of saturated fine-grained soils under cyclic temperatures

Abstract

New thermomechanical models for saturated soils recently developed in the literature very well capture the thermal cyclic deformations of normally consolidated (NC) soils, but this is not the case for slightly overconsolidated (OC) soils. To improve this, a framework based on the reference line (RL) and thermal stabilisation line (TSL) is proposed in the e-ln(p) plane. Whatever the applied thermal solicitations, monotonic or cyclic, the thermoplastic volumetric strains of slightly OC soils are easily predicted from their NC states using the RL and TSL lines concept. It should be noted that the TSL already exists in the literature but requires at least three tests at different over consolidation ratios (OCRs) for its calibration. For this purpose, a simple method is also proposed for determining the TSL line explicitly from the total deformation recorded at the end of the thermal cyclic test (on NC sample). In this way, the number of tests is reduced from three to one. Besides, to better predicting the thermomechanical behaviour of saturated soils, the hardening law is calculated independently for both thermal and mechanical loading cases. Finally, the proposed model is compared with existing recent models as well as experimental data from the literature.