Hydrodynamic Performance and Design Evolution of Wedge-Shaped Blocks for Dam Protection against Overtopping

Francisco Javier Caballero,Rafael Moran,Javier San Mauro,Miguel Ángel Toledo

doi:10.3390/w13121665

Abstract

Dam safety requirements have become stronger in recent years, highlighting, among other issues, the need to increase the discharge capacity of existing spillways and the protection of embankment dams against potential overtopping, which are particularly threatened by the hydrological consequences of climate change. The current economic situation requires solutions that ensure the safety of these infrastructures at an affordable cost. Wedge-shaped blocks (WSBs) are one of these solutions. A more detailed understanding of the performance of WSBs was the objective of this work and, based on this, the evolution of WSB design. An extensive empirical test program was performed, registering hydrodynamic pressures on the block faces and leakage through the joints between blocks and their air vents. A new WSB (named ACUÑA) with a different design of air vents was tested in comparison to Armorwedge™, which was used as a reference case. Moreover, the hydraulic behavior of the WSB was analyzed according to the saturation state of the granular drainage layer. The ACUÑA unit was designed with air vents in the upper part of the riser where the registered negative pressures were higher. Negative pressures were also measured at the base of the block when the granular drainage layer was not fully saturated. Finally, the beneficial effect of sealing some of the joints between blocks was quantified.

Highlights

IntroductionWedge-shaped blocks (WSBs) are modular elements made of precast concrete
Introduction and BackgroundPublished: 15 June 2021Wedge-shaped blocks (WSBs) are modular elements made of precast concrete
The results obtained in the research regarding hydrodynamic pressures on the different blocks tested (w1, ArmorwedgeTM and w2, ACUÑA) and with different drainage situations (d1: free drainage conditions and d2: blocks placed over a layer of 0.20 m thick homogeneous gravel), as well as the seepage from the flume to the different drainage layers (d1 and d2), are summarized

Summary

Introduction

Wedge-shaped blocks (WSBs) are modular elements made of precast concrete They are intended to prevent the erosion and scour in soils caused by water flowing at high velocity. New advances were carried out by Pravdivets [2,4], Bramley, May and Baker [3,5,6,7,8,9], Clopper [10], Slovensky [11], Gaston [12], Frizell [13,14], Thornton et al [15] and Relvas and Pinheiro [16,17,18,19,20], among others [21] From this knowledge, the first technical guide to build spillways using wedge-shaped blocks was published [3], and the ArmorwedgeTM patent was developed by the U.S Bureau of Reclamation (US5544973A)

Objectives

Results

Conclusion