NUMERICAL SIMULATION OF FINGERED FLOW GENERATION AND INFILTRATION CONTROL IN CAPILLARY BARRIER

Abstract

 Capillary barriers are expected to be effective in reducing rainwater infiltration into the ground, and much experimental and theoretical knowledge has been obtained on how to evaluate their performance. On the other hand, fingered flows, which occur due to slight heterogeneity in infiltration from low to high permeable layers, have been experimentally confirmed, but quantitative evaluation methods have not been established. In this study, we attempted to quantitatively evaluate the effect of heterogeneity on impervious performance by 2-D simulations using a spatial distribution model of heterogeneous fields that can take into account the occurrence of fingered flow. The results showed that the impervious performance of heterogeneous fields is more sensitive to the permeability of the upper layer than that of homogeneous fields, and that the impervious performance of heterogeneous fields deteriorates in a long-term evaluation under actual rainfall conditions.