P. Devillers et al., LAW OF THERMODYNAMIC BEHAVIOR FOR UNSATUR ATED SOILS - IDENTIFICATIONIN-SITU OF THERMAL COMPRESSION INDEXES, Canadian geotechnical journal, 33(2), 1996, pp. 250-259
This paper deals with the thermo-hydromechanical behaviour of nonsatur
ated soils. The constitutive relationship presented herein allows for
the prediction of the settlement or swell of an unsaturated soil under
nonisothermal oedometric conditions. Mechanical, hydraulic, and therm
al compression indexes are considered for stress, capillary pressure,
and temperature variables, respectively. The implementation of the rel
ationship in a prediction scheme requires preliminary characterization
of these indexes. The stress-strain and water volume change relations
hips are first presented from a semiempirical point of view for a nons
aturated soil element under nonisothermal conditions. These relationsh
ips allow for the expression of a thermo-hydromechanical constitutive
law for nonsaturated soils and propose a relationship for the change i
n the soil water content. The thermal compression indexes are then det
ermined for a clayey silty sand, first using a reverse method and then
a direct method. This determination is made from experimental data re
corded on a prototype involving heat storage in an aquifer. The values
of these thermal compression indexes are finally compared with the la
boratory values obtained in a thermal triaxial cell on samples of the
same soil.