Modelling of water evaporation from cracked clayey soil

Abstract

A model for predicting water evaporation from clayey soil with desiccation cracks was developed based on a general suction-related model. The effect of desiccation cracks was accounted for by introducing a surface crack ratio (Rc) and a ratio of relative humidity in cracks to that at soil surface (k). The model was validated on the basis of two large scale evaporation experiments in an environmental chamber under controlled atmospheric condition. The results show that soil cracking strongly affects the actual evaporation rate, especially after the falling-rate evaporation stage. Ratios Rc and k are two relevant parameters in describing the effect of cracks on water evaporation in a simple fashion. The introduction of these two parameters allows the three-dimension evaporation problem in cracked soil to be reduced to one-dimension evaporation problem. Comparison between the model predictions and the experimental results shows that with consideration of the effect of desiccation cracks, the model can satisfactorily describe water evaporation from cracked clayey soil under controlled atmospheric condition.