Selection of Most Appropriate Procedures for Seismic Evaluation of Levees Based on Case Histories

The current methodology for embankment dams evaluation is not appropriate for levees of low heights, which have little effect on the stress state of the foundation soil and, therefore, on its response to the seismic action. In many cases the liquefaction potential of the alluvial deposits is not affected by the levee presence, although is the main factor in levee degradation. Lateral spreading of liquefiable foundation is the main cause of small levee cracking and settlement induced by earthquakes. On the other part, the procedures recommended for evaluation of lateral spreading are not directly applicable to the analysis of levees. In this paper both categories of procedures (for dams and for free field affected by lateral spreading) are applied comparatively for evaluation of a case history. This paper summarizes results of different procedures on a case history, where a California levee was severely damaged during Loma Prieta earthquake. Recommendations are made for the analysis of various categories of levees