Analysis of stability of earth dams in overtopping scenarios with the particle finite element method

Abstract

The aim of this work is to study the consequences of an overtopping on the stability of earth dams and its possible failure mode. Rehabilitation and safety analysis of existing dams is nowadays an open field of research. The possibility to define a numerical instrument to provide support for analyzing the failure of a dam is a big step ahead for organizing the intervention measures and for optimizing the economic plan. In fact many existing dams have now to be modified due to the revision of previous design criteria in order to increase their safety. The objective of our work is to develop and validate a new computational method of general applicability that allows treating the above problems. The method will combine advanced finite element and particle techniques. Fluid-structure interaction effects and non-linear geometrical and mechanical effects in the dam material are considered. A mixed Lagrangian and Eulerian approach is used. The fluid behavior is described using a modified form of the Navier Stokes equations in order to consider the effect of a variable porosity. A non linear Darcy law is included in the momentum equation. A level set function is chosen to follow the movement of the free surface inside and outside the porous medium. The structure is described using a purely lagrangian PFEM formulation [1] and [2]. The specific features of PFEM make it appropriate to treat the rockfill material and its large deformations and shape changes. A projection technique allows to perform the data transfer between the fluid and the structure non matching meshes.