Variation in Head and Rate of Discharge in the Non-Steady Seepage Flow

Abstract

By field observation in an actual river-bank where the ground and the embankment are permeable, the seepage water can be regarded as going through them very fast to reach its steady state. Judging from the experimental and analytical considerations carried out to verify the fact, it is found out that it takes much more time to seep through an embankment on the impermeable foundation than that on the permeable one. The solutions proposed by many investigators for seepage through semi-infinite body are compared with each other and the equation of head distribution in the embankment on the thick permeable foundation is explicitly presented. It is also pointed out that the theoretical curves coincide closely with the experimental data, provided the parameters, the coefficient of permeability k and the effective porosity β, are adequately chosen, and then the approximate values of these parameters at the non-steady stage are calculated. The change in the rate of discharge is also investigated, corresponding to the head variation.