State parameter–based thermomechanical constitutive model for saturated fine-grained soils

• Published in: Canadian geotechnical journal Vol. 58; no. 7; pp. 1045 - 1058
• Main Authors: Zhu, Qi-Yin, Zhuang, Pei-Zhi, Yin, Zhen-Yu, Yu, Hai-Sui
• Format: Journal Article
• Language: English
• Published: 1840 Woodward Drive, Suite 1, Ottawa, ON K2C 0P7 NRC Research Press 01-07-2021; Canadian Science Publishing NRC Research Press
• Subjects: Analysis; argiles; Clay; clays; Compression; Consolidation; Constitutive models; constitutive relations; Cooling; Deformation; effets de la température; Fine-grained soils; Fins; Heating; Heating and cooling; Mathematical models; Mechanical properties; Parameters; paramètre d’état; Plasticity; plasticité; Pressure dependence; relations constitutives; Shape; Soil; Soil mechanics; Soil temperature; Soil testing; Soils; state parameter; Stress ratio; Temperature changes; Temperature dependence; Temperature effects; Thermal properties; Thermomechanical analysis; Thermomechanical properties; China
• ISSN: 0008-3674; 1208-6010
• DOI: 10.1139/cgj-2019-0322

This paper presents a two-surface constitutive model for describing thermomechanical behaviour of saturated fine-grained soils at both normally consolidated and overconsolidated states. A thermal-dependent stress ratio-state parameter relation is adopted to account for the effects of temperature on the shape of the state boundary surface (SBS) of soils. In the model, both the size and the shape of the SBS are allowed to vary with temperature, which is evidenced by thermal variation of the mechanical yield loci and the shifts of the normal consolidation line (NCL) and the critical state line (CSL) upon heating and (or) cooling. A thermal yield surface is added for modelling the isotropic thermal deformation of soils more accurately, in particular at overconsolidated states. The mechanical and thermal yield mechanisms are coupled through the temperature-dependent preconsolidation pressure that is controlled by a volumetric hardening law. Based on experimental observations, a nonlinear relationship between the spacing ratio and temperature changes is defined and a simple thermal dependent non-associated flow rule is proposed. The model is validated against some selected experimental results of several soils tested under various mechanical and thermal paths such as drained isotropic heating and cooling, drained and undrained triaxial compression at non-isothermal conditions.