Water Film in Saturated Sand

摘要

In order to investigate the initiation mechanism of landslide and debris flow occurring on a gentle slope. The formation and evolution of water film (or crack) in saturated sand is analyzed by numerical and theoretical simulations under given conditions. First a psudo-three-phase model is presented considering the movement of skeleton and water and the erosion. Secondly, difference method is used to analyze the formation conditions and the evolution of the velocity of water and pore pressure and porosity. Thirdly, a simplified theoretical method is presented based on the consolidation theory to analyze the initiation, expansion and close. It is shown that there are stable water films when some point is blocked and the state keeps unchangeable or there exists a thin layer with very low permeability. Once the blocked point is open, the water film will disappear gradually. The evolution of water film may be calculated by a simplified method. The analytical results are agreement well with that of Kokusho.