Numerical investigation of relief well performance for decreasing uplift pressure under embankment dams

Abstract

Drainage systems for embankment dams are arrangements that collect seepage water in downstream areas. A relief well downstream of a hydraulic structures is one way to reduce the water pressure underneath the structure and thereby improve stability. The design of relief wells includes the determination of the distance of the relief wells from each other, their location, and the well diameters. This study investigates the effects of relief wells on uplift pressure in earthen dams. Solutions were obtained by the finite element method which was used to assess different configurations of the relief wells. For validation, a comparison between analytical solutions and numerical calculations shows good agreement for uplift pressure prediction. Reducing the distance between relief wells or increasing the well diameters results in a reduction of uplift pressure. A two-row arrangement of relief wells showed that a zigzag deployment is superior to a non-zigzag deployment. Linear and nonlinear regression relations are presented for uplift pressure prediction.