Pipeflow is recognized as an important hydrologic control as well as a landslide initiation factor, and the development of a theoretical method to analyze pipeflow process is needed. However, there are few modeling studies of pipeflow, and a general simulation technique for water dynamics in the hillslope scale with soil pipes has not yet been developed. In this study, a general model that describes lateral pipeflow in a hillslope was developed. In the model, matrix flow and pipeflow were calculated by their respective governing equations (Richards' equation and Manning's equation), considering the interaction between t hese two flow systems. Numerical experiments were conducted to analyze the effect of pipeflowon slope stability. Results indicated that pipe clogging decreases the factor of safety and couldbe a factor that triggers landslides, and that pipeflow affects the initiation of debris flow after landslides.
Proceedings of Hydraulic Engineering / Vol. 48, pp.337-342