| Since soils within pavements are usually in an unsaturated state, moisture and temperature in unsaturated soils are affected by climatic factors. A hydraulic gradient due to rainfall causes moisture flow, and a thermal gradient due to temperature change induces not only heat flow but also moisture flow directly and indirectly. Above the freezing temperature, moisture flow under a thermal gradient may be insignificant, but below the freezing temperature, moisture flow will be significant since ice lens may be formed in the frozen soil and thus act as a sink. If ice lenses in a soil fill the soil pores and expand, the soil will heave.; Heat flow and moisture flow have been recognized as coupled processes with complex interactions between them. Thus, many researchers have tried to analyze the coupled heat and moisture flow in unsaturated soils by numerical methods. While soil scientists have focused on the change of temperature and water content in soils, engineers have been interested in frost heave as well as the change of temperature and water content in soils.; This study presents an analysis model by the finite element method for the coupled heat flow and moisture flow in unsaturated soils. The model is applicable to both one-dimensional and two-dimensional problems. The model can be used to predict not only the change of temperature and water content, but also frost heave with time.; The model is tested through comparisons with the results by other methods or models. The results by the model show good agreement with the results by others. The result by a quasi-analytic method is compared with the result of the one-dimensional result of the model. The comparison between the results by the model and measured in a pavement section of U.S. Route 23 in Delaware County, Ohio is presented. The measured result is then compared with the result by Enhanced Integrated Climatic Model Version 2.0 (Larson and Dempsey, 1997). To test two-dimensional model analysis the result by the model is compared with the result by the software, GEO-SLOPE developed by GEO-SLOPE International Ltd. in Alberta, Canada. |
