Assessment of observed of behavior of Sidi El Barrak Dam (Tunisia)

Abstract

Sidi El Barrak is a Tunisian earth dam of height 28 m; it was built in 1999 on a heterogeneous foundation that has a strong dominance of sandy formations. This dam covers an area of 896 km2 and receives about 260 Millions cubic meters of water per year. The foundation of the Sidi El Barrak dam was treated by vibro-compaction over the first 10 meters, to improve the relative density of upper sand layer against the liquefaction risk. Monitoring the behavior of the dam was assured against the hydraulic behavior and topographic auscultation. The recorded peak settlement at the crest level since July 3rd, 2003 until August 2015 was about 18.7 cm. In order to reproduce the behavior of the dam in terms of consolidation, a plane strain numerical model of the dam and soil foundation has been proposed. The simulation of dam behavior using the Mohr–Coulomb model for the material of dike and the sandy layer and by adopting the Soft Soil Model for clay layer led to predicted settlement almost in agreement with measured values. Three options of numerical computation were performed by adopting three constitutive laws of the constitutive materials of the dam and its foundation. The observed behavior of the dam during 15 years (up to date) was successfully predicted by the conducted numerical investigation.