INFLUENCE OF PREFERENTIAL FLOW DUE TO HETEROGENEOUS PORE DISTRIBUTION ON RAINFALL INFILTRATION AND DRAINAGE CHARACTERISTICS

Abstract

 In this study, based on the in-situ measurement results on the fill slope where macro-pores were developed, the influence of preferential flow due to heterogeneous pore distribution on rainfall infiltration and drainage characteristics was discussed. As a result, the following possibilities are shown.

 First, in the slope where macro-pores have been developed, when pore-water pressure and volumetric water content increase rapidly due to rainfall, a preferential flow occurs as the permeability of soil containing macro-pores increases by several orders. And since the preferential flow forms a pseudo-saturated region in a short time, the pore-water pressure increased almost coincident with the rainfall peak due to the subsequent high-intensity rainfall. Accordingly, it is considered that since this pore-water pressure transmission occurs in a short time, the occurrence time of the shallow slope failure may be much faster than the result estimated by the conventional seepage flow analysis same as the past slope failure incidents.