Current State of Knowledge on Thermal Consolidation using Prefabricated Vertical Drains

Several research works have demonstrated that subjecting normally consolidated clays to temperature less than the boiling point of water (100 degrees C) will have positive effects on its hydro-mechanical behaviour. Such effects can be exploited in improving the performance of the well-known preloading ground improvement technique that utilizes prefabricated vertical drains (PVDs). In this review paper, the applicability of a novel prefabricated vertical thermal drain (PVTD) will be presented and discussed using results of large oedometer tests and full-scale embankment tests on soft Bangkok clay. The large oedometer test results gave promising outcomes since the temperature accelerates the rate of consolidation and increases the amount of total settlement. The viability of the proposed technique was also confirmed by the full-scale embankment test results. The success of the proposed technique can be attributed to the thermally induced volume change and the increase in the hydraulic conductivity as the soil temperature increases.