Evaluation the performance of liquefiable soil beneath a water construction under seismic excitation

Abstract

The behavior of soils under cyclic loading plays a crucial role in determining the extent and distribution of ground displacements, which in turn are directly related to the potential for causing earthquake damage. In the literatur, the state in which the soil loses a large percentage of its shear strength when subjected to monotonic or cyclic loading (i.e. earthquake) is called liquefaction. Great effort is carried out by the government through Water Resources and Irrigation Ministry to evaluate and rehabilitate the old water constructions such as the Barrages, Weirs and Regulators along the Nile to repair and enhance the efficiency of those structures, against all the possible problems including liquefaction. Based on factual parameters, estimated from series of field and laboratory tests, numerical study was conducted to simulate the effect of seismic excitation on a water construction rested on liquefiable soil. The case study of the work, Zefta Barrage has been analyzed considering liquefaction prospect in one, two, and three dimensional finite element analyses. The ground motions used in the models are time-histories; real records spectrally matched the spectral acceleration curves for Zefta site using an updated earthquake catalog and updated seismotectonic model. Pseudo Spectral Acceleration curves (PSA) are calculated using probabilistic seismic hazard approach at Zefta site.