Evaluation of Imbibition Process in Porous Media by Invaded Percolation Probability

Abstract

ABSTRACT:The water retention capacity of soil is determined by the texture and structure of the soil and the physical properties of the grain surface. Specifically, it is influenced by various factors such as size and shape of pore, connectivity to neighboring pores, and the contact angle of grains in a bottom-up manner. The water retention curve, a relationship between retained water in soil and matric potential, can exhibit different shapes depending on such factors. However, in our previous numerical experiments with a pore-network model, we suggested that the various water retention curves can be integrated into an almost identical curve regardless of different pore-size distributions when variously saturated porous media are evaluated by an evaluation index derived from the percolation theory. The evaluation method is called invaded percolation probability here, and it was extended from the percolation probability, which evaluates the degree of network connectivity. In this study, more detailed numerical experiments for imbibition process were conducted and the applicability of the invaded percolation probability was investigated. Our results indicated that a common curve of the invaded percolation probability was obtained if pores in the pore-network did not have any correlation with their neighboring pores. In a case where the pore-network had some spatial structure, we found that a different curve of the invaded percolation probability was obtained, and this evaluation method was applicable unless the structure was disturbed.