Performance-Based Seismic Analysis and Design of Earthfill Dams

FUORI CATALOGO

Throughout the history of mankind, people have built dams to store and divert water, and also nowadays earth dams are the most common typology used worldwide to create reservoirs. Earthquakes are the third cause of embankment dam disasters, therefore it is necessary to have a complete understanding of the seismic response of these safety-critical structures. In current practice, earth dams are often assessed using simplified models. However, the main problem with the traditional analysis of earth constructions is that soil properties are always represented using deterministic values. This is an assumption that never happens in reality, wherein the uncertainty in soil properties is inevitable. Moreover, the soil domain is frequently considered as homogeneous; thus its inherent spatial variability is generally neglected. Consequently, both concepts of spatial variability and uncertainty in the soil characteristics are seldom addressed together when studying the seismic behaviour of earth dams. In this report, using an existing dam as prototype model, a performance assessment methodology is presented, in which both uncertainty and spatial variability of soil parameters are accounted for. A comprehensive probabilistic analysis is performed, combining advanced numerical modelling with random field theory and Monte Carlo simulation. As outcomes, seismic demand hazard curves for homogeneous and spatially varying soil properties are constructed, together with fragility curves for several damage states.