Studies on Soil Heating Using Renewable Solar Energy: Fid-Bau Portal

Studies on Soil Heating Using Renewable Solar Energy

Stalin, V. K. / Raja Rajan, K. / Chandru, S. / Hemakumar, J.

Soil heating is one of the methods of ground improvement from a shallow to moderate depth of problematic soils such as soft clay. The existing method of soil heating is done by open fire system, blowing of hot air from furnace, buried of fuels, etc. These methods are considered as toxic or not an eco-friendly. In this investigation, an attempt was made to improve the remoulded soft clay using solar energy-based soil heating. Solar energy is stored in battery backup and the same is used to heat the soil through hot air blower into the predrilled hole surround by soft clay placed in a rectangular box of initial water content at 85% LL of different type of soils (natural soil LL = 80%, kaolinite LL = 30% and bentonite LL = 240%). While blowing hot air, the temperature of the soil at two different depths and two radical distances were recorded for varying time interval. The change in water content was also measured at different depths and distance from the source of heating unit in soils. Results indicated that even though the temperature at the sources is 300˚C, the temperature recorded in soil varies from 32 to 45 °C only, and at any given time. Further, at any time of heating, the reduction in water content was always higher for kaolinite and least for bentonite, and this may be because of poor drainage characteristic (or low permeable nature) of bentonite where the rate of evaporation is less compared to free draining kaolinite soil (high permeable nature).