Scientific Objectives

1. A set of granular materials composed of sand, silt and clay will carefully be chosen and used throughout the whole project by all the fellows as reference test materials to investigate the key scientific issues. [WP1]
2. The mechanical and hydrological properties of the reference materials in (1) will be studied by some element tests in laboratory. These dataset will be used to calibrate the constitutive models in (3). The same materials will be used in laboratory model tests in centrifuge. [WP1]
3. Advanced constitutive models for numerical modelling of slopes and debris flows will be worked out based on the recent research on unsaturated soil and on debris materials. The parameters will be identified with the datasets for the reference materials in (2). Extensive DEM simulations will be carried out to establish some micro-macro relationships. [WP1]
4. Numerical simulations of hydrological-driven slope failure will be carried out by advanced FEM and by sophisticated DEM. The numerical model shall consider the multiphase and the multiscale nature and provide insight into the triggering mechanisms of slope failures. The numerical simulations shall be validated with the help of the datasets of centrifuge model tests and well documented field cases in (8). [WP2]
5. The dynamics of debris flow will be studied by extensive DEM parametric studies, including the influence of model parameters at particle level on the global flow dynamics and the interaction between debris flow and protection structures. Some intricate problems will be investigated, e.g. unsteady flow pattern, bed erosion and sedimentation, particle segregation etc. [WP3]
6. Numerical modelling of debris flows will be carried out based on CFD. The 2D model with depth-integration will be extended to that for 3D binary mixtures and the level set method will be implemented to capture the free surface flow. The research shall bring about significant improvements to the existing runout models. The simulations will be compared with the validation tests in (8). [WP3]
7. PFEM will be used to model both slope failure and debris flow. PFEM is a robust and efficient numerical method for analysis of engineering problems involving the interaction of fluids and solids accounting for large motions. The simulations will be carried out in close cooperation with the work in (2) and (6). It is with this method that a unified treatment of landslides and debris flows shall be realized. The simulations will be compared with the validation tests in (8). [WP2, WP3]
8. The dataset of validation tests consists of small-scale model tests in centrifuge (landslides and debris flows), which is available at UNOTT and BOKU and well-documented real cases from practice. Soil slopes with reference materials will be tested for artificial rainfall under controlled climate conditions. Moreover, well documented real cases will be provided by the stakeholders. The dataset will be used to validate the simulations in (4-7). [WP4]
9. By simulating well documented benchmark events in practice with different numerical techniques, we will establish best practice in numerical modelling of landslides and debris flows considering the variability of the material properties. [WP4]
10. A permanent network to disseminate the experimental database and the validation methodologies will be established. This will include the validation database, the reference materials characterisation database, as well as the documentation of validation and model calibration methodologies. Once operational it will provide a continued influence on research and practice in landslides and debris flows. [WP5]