Application of thermal flux for establishing soil–water characteristic curve of kaolin

Abstract

Application of field and laboratory insertion tensiometers, pressure membrane extractor, PME, a dew point potentiameter, WP4, and a geotechnical centrifuge for establishing soil–water characteristic curve (SWCC) of fine-grained soils is well established. However, these techniques are quite elaborate, cumbersome to follow and resort to invasive and destructive techniques for moisture content determination. This calls for development of an alternate technique that can be employed for (a) creating unsaturated state of the soil mass, and (b) measurement of moisture content and soil suction in a non-destructive and non-invasive way. Needless to say, such a technique would be quite helpful for establishing the SWCC, quite easily and rapidly. In this context, possibility of creating unsaturated state of the kaolin soil mass by imposing thermal flux was investigated and its details are presented in this paper. This technique in conjunction with electrical measurements (i.e. voltage in the soil mass) has been found to be quite promising for establishing the SWCC. Validity of the proposed technique has been demonstrated by comparing the resultant SWCC vis-à-vis the SWCCs reported in the literature for this soil and Fredlund et al. (1997; 3rd Brazilian Symposium on Unsaturated Soils, Rio de Janeiro, Brazil, 1997, April 22–25, pp. 13–23) pedo-transfer function (PTF) available in the SoilVision database.

Keywords:

• kaolin
• thermal flux
• electrical measurements
• soil–water characteristic curve
• unsaturated soil hydraulic conductivity