Numerical investigation of liquefaction-induced settlement and instability on embankment dams (a case study)

Liquefaction is a phenomenon in which soil loses its bearing capacity, large settlements occur, and it may cause lateral spreading and failures. Numerous studies and cases in the world have shown that liquefaction occurs in the alluvium foundations of earth dams. The occurrence of widespread liquefaction can cause the entire dam to fail. In this paper, methods of assessment and numerical analysis have been used to assess the Shourijeh reservoir dam liquefaction. According to the latest criteria, it was observed that by considering the acceleration of the maximum credible earthquake level (MCE), the alluvial foundation of Shourijeh Dam is liquefiable in some areas. The dynamic analysis and liquefaction modelling based on linear equivalent analyses have been used. By analysing the sliding block and sliding circles based on the limit equilibrium method and the Newmark sliding block analysis, the stability safety factors of slopes for Shourijeh Dam after the earthquake have been investigated for three different earthquakes and various states of reservoir water level. Stress redistribution analysis has been used to estimate the permanent deformation of the structure due to seismic loading. The results of this research, in addition to providing helpful information regarding the performance of earth dams against liquefaction and its effects, have shown that the settlements caused by liquefaction in the studied dam are not so large that they would cause extensive damage and collapse of the dam at the MCE level.