Numerical modeling of water-heat-vapor-salt transport in unsaturated soil under evaporation

摘要

Evaporation-induced soil salinization will threaten the durability of engineering buildings, and it is crucial to study the coupling effect of water-heat-vapor-salt (WHVS) for anticorrosion of porous materials. To analyze the coupled system, a modified and developed WHVS transport model is proposed under the conditions that the film water transport theory, surface tension affected by salt, the filling effect of precipitated salt on soil pores, the residual volumetric air content, the effect of salt on heat transport and storage and the effect of vapor flux and thermal radiation on thermal boundary are all taken into account. The predictions are validated and analyzed by the results obtained from evaporation experiments under different boundary conditions. The data of silica sand are from the literatures ([16,17,57]), and the data of silty clay are from our laboratory test. The results indicate that the calculated water content, solute concentration, temperature and evaporation rate are in good agreement with the experimental data, especially for silty clay. For silica sand, there are some deviations in concentration and temperature, and the overall agreement is satisfied. The consistency between the simulated and measured data shows the effectiveness of proposed model and that the model can be applied successfully in soil science and groundwater hydrology and can be extended to related disciplines.