Soil thermal conductivity is a key factor governing its thermal regime. In the present study, we measured the thermal conductivity of Toyoura sand and glass beads using a heat probe method to clarify the effects of gravimetric water content (w) and NaCl concentration (C) and to evaluate the estimation effectiveness of four models (Mochizuki, de Vries, Noborio and Kasubuchi). The de Vries and Ka…