2D thermal consolidation model for saturated clay considering thermal contraction

Abstract

The realistic simulation of thermo-hydro-mechanical (THM) coupling response of soil media is fundamental to the design of thermal-related geotechnical engineering. The saturated normally-consolidated (NC) clays experimentally exhibit thermal contraction behavior when heated under drained condition, whereas it is rarely considered by existing THM coupling model. In this study, a unified constitutive relationship of saturated NC clays is proposed to achieve the sound consideration of the thermal contraction. The thermal contraction is essentially a coupling result of three deformation processes including thermal expansion, rebound caused by the generation of thermal excess pore water pressure (EPWP), and contraction induced by the dissipation of thermal EPWP. Accordingly, a THM coupling model is established for a two-dimensional thermal consolidation problem of the saturated NC clays, and the corresponding semi-analytical solutions are derived under a time-dependent strip thermomechanical load through Laplace-Fourier transform, and they are validated by comparing with existing solutions. Based on proposed model, the THM coupling characteristics of the saturated NC clays are investigated in depth. The outcomes indicate that thermal load induces not only positive but negative EPWP which is attributed mainly to the seepage of pore water. Overall, when subjected to drained heating, the saturated NC clays first experience heave and then settlement, and finally exhibit settlement. Among them, the ultimate settlement is mainly related to temperature.