Assessment for the spatial variation characteristics of uncertain thermal parameters for warm frozen soil

The uncertain thermal parameters of warm frozen soil are the key factors for computing the stochastic temperature field, and the spatial variability can lead to the randomness of thermodynamic characteristic. In this study, a series of thermal parameters tests for the warm frozen soil are carried out, and the thermal conductivity, heat capacity and thermal diffusivity for the different temperature (from −1.8 °C to 0 °C) are obtained. Then the variance function and the scale of fluctuation for the uncertain thermal parameters are estimated on the basis of the random field theory. The results shows that the variance functions for the thermal conductivity, heat capacity and thermal diffusivity decreased along with the increase of averaging distance. The scale of fluctuation for the thermal conductivity is between 0.96 m and 1.25 m under different freezing temperature condition; the scale of fluctuation for the heat capacity is between 0.88 m and 1.15 m, and the scale of fluctuation for the thermal diffusivity is between 0.75 m and 1.13 m. This study can improve our understanding of the spatial variation characteristics of uncertain thermal parameters for warm frozen soil and provide a theoretical basis and reference for the stochastic thermal analysis of frozen soil engineering.