Experimental study on thermal performance of quicklime (CaO) energy pile aimed to thaw the warm permafrost ground

Abstract

This study investigated the thermal performance of quicklime (CaO) energy pile aimed to thaw the warm permafrost ground. Three laboratory experimental models were made by three typical soils in the Tibetan Plateau permafrost regions. The variations of soil temperature, heat flux, and soil volumetric water content were monitored and analyzed during the warm permafrost thawing process. The results show that the same quicklime pile has different thawing effects according to the frozen soil types. The largest thawing range and maximum soil temperature value were observed in the sandy soil, followed by the silty soil, and then the clay. Furthermore, the thawing radii are around 20 cm in all three frozen soils. The highest soil temperature is 38.5 °C in the sandy soil. Soil water content kept almost at the same value before and after the experiments and exerts a limited impact on the physical property of soil. In addition, distinct energy pile expansions were observed at the end of experiments. This pile expansion indicates that the soil density increased around the quicklime piles, and hence improved the strength of the thawed ground. Overall, the quicklime (CaO) pile is an efficient and economic approach to improve the thermal and mechanical stability of the warm permafrost ground.