The effect of hydrodynamic pressure of the dam reservoir caused by the earthquake on the results of 3D dynamic analysis of concrete face rockfill dams

Concrete faced rockfill dams (CFRDs) are among the structures that due to their advantages such ease of construction and low execution costs,have attracted more attention nowadays.Due to the fact that during large earthquakes,the hydrodynamic pressure will be large and cannot be ignored,the main purpose of this research is to apply reservoir hydrodynamic pressure of dam reservoir caused by the earthquake and investigate its effects in three-dimensional analysis using ABAQUS software.The considered dams in this study have 70,100&130 meters height located in the valley with the length to height ratio of  (L/H=1)&(L/H=3). To investigate the effect of the earthquake,a maximum scaled acceleration of 0.6g was used in the carried out analysis.Linear elastoplastic Mohr-Coulomb material model for rockfill embankment, an elastic material model for rocky foundation,and the concrete damage plasticity model for the concrete face are adopted.In order to take into account,the effects of the reservoir hydrodynamic pressure,the reservoir water is represented by acoustic elements with the Lagrangian formulation.It is found that considering the hydrodynamic pressure, increases the settling values by 5to80%,plastic strain by 37%, surface compressive stress by 20to57% and maximum dam crest acceleration up to 2 times in some of the analyzed dams.