Understanding the effects of high temperature processes on the engineering properties of soils

Abstract

High temperature processes such as in situ smouldering and thermal remediation techniques can achieve rapid removal\nof organic contaminants from soils in much shorter time periods than traditional remediation technologies. Thermal remediation\nprocesses use heat or heated water to volatilise the contaminant within the soil to enable its extraction. High temperatures affect the\nparticle size distribution, mass loss, mineralogy and permeability of the soil. In sandy soils, the particle size decreases with increasing\ntemperature due to a mobilisation of fines, which is likely due to the bond of fines to the sand grains being affected by temperature. In\nclayey soils, the overall particle size increases with increasing temperature due to aggregation and cementation of the clay fraction.\nPermeability seems to be affected by treatment type rather than temperature alone, comparing heat treated and smouldered samples\nshowed an increase of sand permeability by approximately two magnitudes. This study illustrates the effects of high temperature and\nsmouldering processes on soil characteristics and dynamic behaviour. Monitoring during and after aggressive remediation is advisable\nso that rehabilitation measures can be implemented before site redevelopment.