This study investigates the effects of heating on the transient behavior of the geologic media surrounding the tunnel involved in a severe fire, which typically involve extreme temperature and prolonged duration. Currently, there is little research being done in this area. An analytical model has been developed to predict the temperature rise of dry soil in the experimental soil column configuration and there is good agreement between analytical and experimental results. In water-saturated soils, the onset of convection happens in soil of higher permeability and there is propagation of a saturation temperature front at the onset of boiling, with greater propagation speed as permeability increases. There is also significant increase (~500%) in the pore water pressure building up in finer-grained saturated soil. This project then examines how these thermal transport modes and the pore water pressure increase in the soil medium can affect the stability of the tunnel lining.