This paper presents the results of an experimental study carried out using modified consolidation tests with the needle probe method to measure thermal conductivity. Experimental results are used to assess theoretical and empirical models, which are categorized into four groups, to calculate the thermal conductivity of saturated kaolinite.
INTRODUCTION Heat transfer in clayey soils is an important factor that must be considered in the design of engineering structures, such as clay barriers for nuclear waste repositories (Gera et al., 1996; Tien et al., 2004) and vertical drains in soft Bangkok clay (Abuel-Naga et al., 2008). Many researchers have discussed the factors affecting thermal conductivity in soils, and major factors have been established (Kersten, 1949; Mickley, 1951; Johansen, 1975). Thermal conductivity depends on dry density, water content, particle size, unfrozen and frozen condition, saturation degree and soil components. However, there are few studies on the thermal conductivity of saturated clay because laboratory tests must be performed under conditions that minimize specimen disturbance while confirming saturation level and carefully control the heat boundary conditions of the apparatus (Abuel-Naga et al., 2008). Penner (1962) measured the thermal conductivity of remolded saturated Leda clay. The soil sample was cut and predrilled to place thermocouples within the sample, but it is possible that the tested specimens were disturbed during cutting and drilling. The measured thermal conductivity increases as the temperature gradient between the top and bottom boundaries increases. These approaches can be used to estimate the thermal conductivity of saturated clay, but no rigorous research that evaluates these models has been reported for the thermal conductivity values of saturated clay. This paper presents carefully controlled laboratory testing data obtained from consolidation tests with thermal conductivity measurement. Further, experimental results are utilized to assess the accuracy of previously developed models.