Both hydrologic and thermal transport properties play a significant role in the movement of heat through permeable sedimentary material; however, the thermal conductivity is rarely characterized in detailed spatial resolution. As part of a study of the movement of thermal plumes through a sand and gravel aquifer, we have constructed a two-dimensional profile of thermal conductivity. This work consisted of: (i) measuring the thermal conductivity of the soil solids, λs, for the main stratigraphic units using the steady-state divided-bar apparatus and estimating conductivity from mineral composition; (ii) measuring the volumetric water content and porosity using crosshole ground-penetrating radar; (iii) evaluating four models used to predict the apparent thermal conductivity, λ, of variably saturated soils and selecting the best model using the information-theoretic approach, (iv) calculating the λ field on a 0.25-m square cell grid using measured data and the selected model, and (v) simulating thermal transport within the two-dimensional domain using a finite element numerical model. The apparent thermal conductivity in the saturated aquifer ranges from 2.14 to 2.69 W m−1 K−1 with a mean of 2.42 W m−1 K−1 Numerical simulations show that the heterogeneous thermal conductivity field results in increased thermal dispersion that is most pronounced at the plume front. Our values for λ and λs may be used for glacial soils with similar mineralogy and texture. Our methods may also be used at other sites to construct the thermal conductivity distribution.
Additional publication details
|Publication Subtype||Journal Article|
|Title||Characterizing the two-dimensional thermal conductivity distribution in a sand and gravel aquifer|
|Series title||Soil Science Society of America Journal|
|Other Geospatial||Tricks Creek Watershed|
|Google Analytic Metrics||Metrics page|