Reinforcement project of the levee of the « Val d'Authion »

Abstract

Strengthening the levee of Val d'Authion was declared as a public interest project on 31 August 2000. The 2000-2006 contract between the State and the regional authorities is devoted to the definition of the technical solutions and the construction of the strengthening works. The article comments the results of the studies and particularly insists on three aspects : the evaluation of the failure risk, the choice of the technical solutions and the design and dimensions of the watertight barrier. According to the land properties constraints and the geotechnical features along the levee, different technical solutions are recommended. The watertight barrier solution is well adapted to the urban context. The detailed fl ow and seepage analysis and the stability computations for different configurations showed that dimensioning the barrier characteristics is a complex task. The analysis shows the difficulty for defining the safety criteria against piping in the case of old levees.