New Role of Drainage Systems in Dam Stability

Abstract

Foundation drains have long been utilized for reducing uplift pressures under masonary dams. It has also been widely assumed that when tension develops at the heel of a dam, that full headwater pressure extends for the entire tension zone. Recent studies, which are described, demonstrate that foundation drains continue to function and result in significantly lower uplift pressures. As a result, dams subject to more severe loading conditions than those considered in the design may still be stable. The finite element method of analysis is used in the studies to estimate the dimensions of a potential crack under a gravity structure, which includes an upstream key into the foundation rock mass and internal drains.