Abstract

The paper presents the results of the application of the Particle Finite Element Method (PFEM) to the analysis of landslides in reservoirs. This is a complex phenomenon, because of the interaction between the landslide, the still water in the reservoir and the dam. PFEM combines a Lagrangian approach with the solution of the governing equations of the problem using the FEM. A mesh connecting the initial set of particles (nodes) is re-generated in every time step. Some validation cases are presented, in which PFEM results are compared with experimental data. More complex calculations have been made over the actual geometry of reservoirs taken from the cartographic information of the sites. In these cases the wave generation, its propagation and dam overtopping are reproduced. Finally, Lituya bay rock slide in which 90 × 106 tons of rocks fell on the bay, generating a huge wave that caused a maximum run-up of 524 m on the opposite shore, has been simulated in 3D. The results show that PFEM is a useful tool in risk assessment related with landslides in reservoirs as it gives a good approximation to the potential affections, thus allowing the appropriate design of protection measures.

Abstract

Flow through coarse porous media, as rockfill, gravel or sand of big size, exhibit a non linear relation between hydraulic gradient and seepage velocity. This behavior is observed when water flows over the crest of a rockfill dam, seeps into the downstream shoulder and moves through the rockfill voids. A finite difference scheme is used here to solve this problem through numerical modeling. It is implemented in the code MNLEE.RDS for solving dam overtopping problems. In addition, a procedure is provided to solve the coupled problem of flow over and through the rockfill dam. For that purpose, the concept of «law of flow exchange»is introduced.