Effect of a stiff thin Foundation soil layer’s depth on dynamic response of an embankment dam

In 2002, Zeyzoun Dam failure, that is an embankment dam located at the northwest of Syria, made a big Awareness of the effects of the lack of Geotechnical investigations and concern given to seismic design, geological conditions and location of the dam. Zeyzoun dam location, in the vicinity of the Dead Sea fault system, emphasizes the importance of analyzing the effects of lithological stratum in dam foundations on dam seismic stability. This paper is concerned with the influence of a high permeable soil layer that has different static and dynamic properties, and exists at different depths in dam foundation. Geo-studio software, a Geotechnical program that applies the finite element method and can consider analysis like seepage, dynamic analysis and slope stability, used to build and analyse numerical models. The results of dynamic analysis showed rising of phreatic line level in dam body, amplification in dam dynamic response, increasing in pore-water and excess pore water pressure and decreasing in stability factors of safety, along with decreasing of the thin layer depth.