Evaluation of diversion length by numerical simulation for design of the capillary barrier

Abstract

Capillary barrier (CB) is used as a rainwater infiltration control technique. And the CB effect results mainly from differences in water-holding capacity and permeability between the sand layer and the gravel layer. Water-holding capacity or CB diversion length has been evaluated by the laboratory soil experiments. But, there is no case where the diversion length that important parameter for the design of CB was evaluated by numerical simulation. In this paper, in order to study the above problem, we investigated whether the penetration phenomenon of slope CB ground can be reproduced by two-dimensional numerical simulation(HYDRUS-2D) for the observation result of the diversion length obtained by laboratory soil experiment. And, evaluated focusing on the diversion length and the bottom flow rate distribution. As a result, compared with the experimental data of the large soil tank, it is possible to show moisture dynamics considerably accurately and clarified the possibility of being applicable to the design of CB.