Experimental and numerical study of upstream slope stability in an earth dam reservoir under rapid drawdown conditions

The rapid water level drawdown of the dam reservoirs is one of important factors of earth dam stabilities. This phenomenon might occur over the lifetime of the earth dams and levees. In order to investigate the effect of the hydraulic conductivity on the rapid drawdown of water level, an experimental model was constructed in experimental flume. By obtaining the hydraulic parameters of the materials, the flow through this model was modelled by SEEP/W software. After validation of hydraulic conductivity with the numerical model, the results were compared with the observed data. Finally, a good agreement is observed between the experiments and predictions. Furthermore, the saturated and unsaturated simulations indicate that the unsaturated model has a much better agreement with the experimental model. It is found that the unsaturated model is more convenient for the simulation flow through the homogenous earth dam than the saturated model.