The Effects of Saturated-Unsaturated Hydraulic Properties on Residual Water Level in upper Zone of Rockfill Dam due to Rapid Draw-down

Abstract

In this research, the effect of hydraulic properties on the stability of rock-fill dam and the behavior of residual groundwater level during rapid drawdown are discussed. Long term field measuring results indicate. that residual pore pressure has not developed in the upstream rock zone. This tendency has continued for the past 24 years since the completion of the rock-fill dam. The results of numerical analysis of the behavior of residual groundwater level and evaluation of stability show that the saturated hydraulic conductivity of actual rock-fill material, unsaturated properties of rock-fill material and the dependency of permeability on hydraulic gradient (non-Darcy phenomenon) are important in the design of rock-fill dams.