Articulated Concrete Block Stability Assessment for Embankment-Overtopping Conditions

Abstract

Articulated concrete block (ACB) revetment systems are widely used for channel lining and embankment protection. Current approaches for prediction of ACB system stability use a moment stability analysis with a ratio of the boundary shear stress to critical shear stress to account for all hydrodynamic forces, which results in the exclusion of the flow velocity. Two embankment-overtopping laboratory data sets for a given ACB system were initially evaluated using the current industry-accepted design method. A new stability analysis method, termed the shear and velocity stability assessment method, was developed for ACB systems with embankment-overtopping flow, which uses a moment stability analysis in which hydrodynamic forces are computed using both boundary shear stress and flow velocity. A database was developed that included overtopping tests for three ACB systems with varying embankment slopes and lengths. The current design methodology accurately predicted stability for 67% of the tests and the instability for 40% of the installations. The shear and velocity assessment method accurately predicted stability for 91% of the tests and instability for 80% of the installations.