Abstract:

The construction of earth dams on active faults presents a risk of instability. The Ourkiss dam, built 14 km south of the town of Ain Fakroun, is a heterogeneous type of dam made of clay and alluvial materials, with a watertight geo-membrane lining on the upstream face of the dam and on the dam fanks. Due to its location close to active faults, the dam could be damaged by instability in the event of a very strong earthquake. For this reason, in this article a comparison between two study approaches is made: one is quasi-static based on a failure analysis due to the efect of normal and reverse fault propagation. Diferent angles of inclination are applied by sliding through the Ourkiss dam at the end of construction and in the flled state. The other approach is based on the dynamic efect of the 2003 Boumerdes earthquake (magnitude 6.9 on the Richter scale), modeled with a sinusoidal propagation velocity applied to the model base in the horizontal direction. The results obtained for both approaches are presented in terms of shear deformations developed at the dam foundation and dike. They show that the deformation values found by the quasi-static method are greater than those found by the dynamic method.