Numerical Investigation of a Saturated and Unsaturated Soil-Atmosphere Model

A road is often built with soils compacted at their optimum water contents to achieve the best performance. Soils are sensitive to small water content variations and the ambient environment controls the soil water migration after construction. The soil-atmosphere interaction is a dynamic process under the influence of ambient climatic conditions, such as wind speed, solar radiation, precipitation, air temperature, relative humidity, vegetation evapotranspiration. The complexity of the problem makes it very difficult to reasonably evaluate the roadway long-term performance. This paper aims at evaluating the soil moisture variations within a pavement structure under the influence of ambient atmosphere. A hydro-mechanical-climatic model for saturated and unsaturated soils was first proposed. The climatic data are readily available from a local weather station to establish the flux boundary conditions for numerical simulation. Half of a two lane road was simulated to evaluate the moisture migrations within the pavement structure. Simulation results showed that the proposed model able to evaluate the dynamic soil moisture migration under the influence of ambient climatic changes.