Numerical implementation and solution strategies for a thermo-elastoplastic-viscoplastic model for cohesive soils

Thermal-mechanical analyses of soils are complicated by the porous nature of the material. Macroscopically soils exhibit an anisotropic, inelastic, hardening (and softening), time- and temperature-dependent behavior. To further complicate matters, the thermal properties of soils are not as well known as those for other materials such as metals. Several important problems have recently arisen that necessitate the realistic prediction of thermal-mechanical behavior of soils. The analysis of such problems requires a general but practical methodology that accounts for not only material non-linearities and thermo-mechanical coupling, but also for time-dependent characteristics of soils.

This objective has been realized by extending a generalized bounding surface model, originally developed for isothermal analyses of saturated cohesive soils, to consider temperature effects. Besides accounting for thermal-mechanical coupling and for the inelastic nature of soils, this model includes time-dependent behavior. This latter aspect appears to be a novel proposition in thermo-mechanical modeling of soils.

The emphasis of the present paper is on the numerical implementation and solution of the aforementioned model for thermo-mechanical analysis of saturated cohesive soils. It is shown that the consideration of time effects in the analysis introduces no additional complexity into potential algorithms used in the solution of coupled three-field problems.