EFFECT OF INFILTRATION CHARACTERISTICS OF EARTH MATERIALS ON CAPILLARY BARRIER PERFORMANCE

Abstract

 A capillary barrier system is the control technique of water flow adopted in waste landfills. A capillary barrier system constitutes a finer soil overlying a coarser one. The infiltration water is retained by the suction of the upper fine soil layer, and the infiltration water into the lower layer is halted. When the amount of infiltration water increases, the water across the interface between the finer soil layer and the coarser one infiltrates. When the constituent materials for the capillary barrier structure are selected, they are empirically selected based on their grain size characteristics, and their hydraulic properties are not considered. In particular, the performance of capillary barriers is dominated by the hydraulic property of the fine-grained soil that is the constituent material, and research has been conducted focusing on those characteristics.

 This study focused on the hydraulic properties of the constituent materials for the capillary barrier, and the diversion capacity with different combinations of earth materials is evaluated. From the experimental results, the breakthrough mechanism of the capillary barrier known from the previous studies is verified. The diversion capacities are evaluated using the index that considers the hydraulic properties of the constituent materials, and these results imply that the smaller the index, the greater the diversion capacities.