抄録
The aim of this study is to evaluate a saturation formula of flow in porous media and to integrate the saturation formula into an Atmosphere (gas) － surface water two phase-flow system. It was clear that a distribution of water saturation obtained by the saturation formula of flow in porous media was consistent with that obtained by pressure formulas with modified Picard method when only a porous medium with a bank was simulated by these formulas. Numerical simulation method with the saturation formula for a system coupling atmosphere, surface water and porous media could reproduce flow of the surface water overflowing a bank made of a porous medium and the variation in the water saturation in the bank. As a result, it was confirmed that gas pressure in the bank rose from 0.4 kPa to 5 - 8 kPa when water overflowed the bank and there was partially unsaturated zone in the bank. It is generally known that this phenomenon occurs when gas in porous media cannot escape outside. Therefore the numerical simulation method with the saturation formula of flow in porous media can simulate the system coupling atmosphere, surface water and porous media with unsaturated zone.
