Coupled fields in a deformable unsaturated medium

This paper considers several problems involving coupled heat-moisture-air f low in deformable unsaturated media. A set of coupled non-linear governing equations expressed in terms of displacements, capillary pressure, air pres sure and temperature are used in the analysis. The mathematical model accou nts for fully coupled heat and moisture flow, volume strain effects on wate r-air-heat flow, stress and temperature dependence of the water retention c urve, heat sink due to thermal expansion, phase change between liquid water and vapour water, and compressibility of liquid water. Numerical solutions are obtained by using the finite element method. Comparisons with existing analytical and experimental results for problems involving infiltration, d rying-rewetting (hysteresis effects) and heating confirm the general validi ty of the present mathematical model. Coupled fields in a confined clay cyl inder are also examined. It is found that consideration of absorbed liquid flow due to thermal gradients (thermo-osmosis effect) results in increased drying and shrinkage near the heated boundary. The case of a confined clay cylinder under combined heating and infiltration is also studied. Important features of coupled fields are discussed. (C) 1999 Elsevier Science Ltd. A ll rights reserved.