Abstract: A generalized equivalent-continuum method is presented for calculating variably saturated seepage flow in fractured porous media. The model neglects fracture capillarity, sets up a threshold composite saturation value that corresponds to a prescribed pore saturation, and assume: (1) if the composite saturation in a fractured porous medium is less than the threshold saturation, water flow can take place only in the pores, and the fractures are free from water; (2) otherwise, if the composite saturation exceeds the threshold value, water enters and flows inside of the fractures. Various equivalent-continuum calculation methods are analyzed and compared. In order to illustrate the features of the proposed method, a calculation example is provided for modeling of coupled water and heat transport in variably saturated fractured rocks. The results indicate that the presented method is relatively general, and can be employed to model the main features of variably saturated seepage flow in fractured porous media.

Key words: fractured porous media, equivalent continuum, variably saturated seepage flow