Thermally induced volume change and excess pore water pressure of soft Bangkok clay

This paper presents the results of an experimental investigation carried out to study thermally induced volume changes under drained heating condition and thermally induced excess pore water pressures under undrained heating condition of soft Bangkok clay. The clay was heated up from room temperature (25 °C) to 90 °C using a modified oedometer and a triaxial test apparatus, respectively. The clay was found to exhibit temperature induced volume changes and temperature induced excess pore water pressures, in the range of temperatures investigated, depending mainly on the stress history. A theoretical microstructure mechanism that can interpret the thermally induced volume change behaviour at different stress conditions is presented in this study. Furthermore, the thermally induced excess pore water pressure behaviour at different stress conditions is explained using the unloading–reloading hysteresis of the typical soil consolidation curve. The results of this study provide additional data that can enhance the understanding of the thermo-mechanical behaviour concepts of saturated clays.