Debris flows with pore pressure and intergranular friction on rugged topography

The dynamic behavior of debris flows features the interplay of a non-hydrostatic pore-fluid pressure with the non-linear deformational behavior of the granular skeleton and the internal contact stress between grains. This complex physical background is considered by amending the classical depth-integrated modeling for granular-fluid flows by two additional fields, an extra pore-fluid pressure and a hypoplastic intergranular stress. A scaled and depth-integrated model is developed and transferred into a system of terrain-following coordinates, enabling the application on rugged topography. With this model, numerical investigations are carried out, using a non-oscillatory, shock-capturing central-upwind scheme. Parameter studies show the general impact of the additional fields, completed by comparison to the experimental results of a dam break scenario. Furthermore, application to the landslide event at the village of Hsiaolin in Taiwan, 2009, show the capability of the model to cope with large scale scenarios. The results show that the model and its implementation provide insights in the flow dynamics and the possibility to application on complex topography, considering an enhanced approach to the physics of debris flows.