Determination of flow, solute transport and thermal parameters of silty and sandy soil using laboratory infiltration experiments.

Modeling the process of water flow, heat transfer and transmission of soil contamination requires hydraulic parameters, thermal conductivity and dispersion coefficient in soil. The purpose of this study is to evaluate the characteristic parameters of these properties from an infiltration test of flow and transfer of heat and soluble materials. Data collection were done during the two infiltration experiments, one was recorded for 24 hours in a sand column and another for 36 hours in a silt soil column. To monitor the temperature of the soil at depths of 4, 8 and 12 cm in each column, thermal sensors were installed and the temperature of the infiltrated water was regulated at 40 ° C and the steady infiltration of a source was monitored by the peristaltic pump. A solution of one molar of KCl in a steady state condition was injected on each column of sand and silt soils and the Cl concentration and temperature was recorded during the sampling of water and sensor readings at depths of 4, 8 and 12 cm. The hydraulic parameters of the soil (shape parameters in the van Genuchten equation  and n), the transport parameter (longitudinal dispersion coefficient), and the soil thermal conductivity parameters (coefficients b1, b2 and b3 in the Chang and Horton soil heat transfer function) was estimated using inverse modeling techniques. Validation of the results was performed by comparing the measured and simulated Cl concentration and the heat data by the model using the calculated root mean square error RMSE and R2 coefficient. The most valuable result of this research is the use of the cheapest tracer, ie, temperature, along with the concentration data, to obtain unique solutions to the estimation of the hydraulic functions of sand and silty soils by inverse solution.