Incorporating Hysteresis in One-dimensional Seepage Modeling in Unsaturated Soils

摘要

To understand better the influence of soil-water characteristic hysteresis on rainfall infiltration and pore-water pressure distributions in unsaturated soils, an analytical solution to the one-dimensional governing partial differential equation considering hysteresis is derived using a Fourier integral transformation. The analytical solution considers time-dependent and arbitrary initial pore-water pressure distributions, as well as a time-varying rainfall flux process at the ground surface. An exponential function is used to represent the hysteretic Soil-Water Characteristic Curve (SWCC) and the relationship between hydraulic conductivity and pore-water pressure. The calculated results demonstrate that the critical point, the intersection between wetting and drying domains in one-dimensional unsaturated seepage, is influenced by many factors. The hysteresis in soil-water characteristics is an important factor in infiltration process influencing the pore-water pressure profiles in unsaturated soils. The effects of hysteretic parameters on pore-water pressure profiles are also analyzed. The value of a in the hysteresis model is found to be the most significant factor influencing the pore pressure distributions.