MOISTURE RETENTION OF A SWELLING SOIL UNDER CAPILLARY AND OVERBURDEN PRESSURES

The moisture content in a rigid soil varies with capillary pressure. O n the other hand the moisture retention properties of a swelling soil are functions of capillary pressure and overburden pressure. An unload ed moisture retention curve for a swelling soil can be determined foll owing the same laboratory procedures used for the rigid soils. Determi nation of the moisture contents due to combined effects of capillary p ressure and overburden pressure, however, require a sophisticated expe rimental setup. The present study presents a method to obtain the mois ture content constitutive surface for a swelling soil as function of c apillary and overburden pressures by using more easily measured unload ed moisture retention curve and consolidation curve. The method consid ers that the moisture ratio contours at the constitutive surface can b e represented by an ellipse equation. The proposed method was compared with laboratory results and found to be acceptable, particularly in v iew of the relative ease of the method. (C) 1997 Elsevier Science B.V.