ADVANCING CAPPING TECHNIQUES FOR EFFECTIVE RAINFALL INFILTRATION CONTROL USING CAPILLARY BARRIER SYSTEMS/FUNCTIONS

Abstract

Capillary barriers are a method of controlling rainfall infiltration. Specifically, it is created by layering a sand layer on top of a gravel layer due to the difference in water retention properties of the soil. Using this technique, infiltrating water in the soil, such as rainfall and groundwater, accumulates at the boundary of the two layers and flows naturally along the gradient. Capillary barriers are created from naturally occurring materials and have the advantages of excellent lateral drainage and economic efficiency. Specific applications include top covers for the final refuse disposal and the removed soil. Many laboratory experiments have been conducted on the limiting length of capillary barriers. However, there are few examples of numerical simulations on capillary barrier function, and the performance of the capillary barrier function has not been clarified. Therefore, in this study, rainfall infiltration analyses were conducted on model-scale and full-scale to explain the capillary barrier function's mechanism and evaluate and study its usefulness in full-scale ground. As a result, it was clarified that the total hydraulic head and suction realize the impervious function of the capillary barrier. It was also confirmed that the capillary barrier functions in both the model and full-scale ground and that the accumulation flow depends on the saturation of the ground.