Study of Embankment Performance during Overtopping and Throughflow. Report 3. Model-Prototype Comparison Studies

摘要

It was attempted to model two fairly well documented embankment overtoppings, the Clarence Cannon and Bloomington Lake overtopping failures. Additionally, the results of modeling in two dimensions versus modeling in three dimensions are investigated and discussed, as well as a study of the effects of nonhomogeneous embankment cross sections on erosion. Centrifuge modeling of Clarence Cannon and Bloomington Lake overtopping events consisted of four tests each at 1/80th full scale. Materials used were fairly noncohesive soils and fairly cohesive soils in an attempt to bracket prototype behavior rather than to duplicate a precise event. During testing, the centrifuge was repeatedly started and stopped in order to take measurements of erosion resulting from overtopping. Agreement between scale models and documented prototype behavior was not especially good, but the study did confirm that noncohesive soils are considerably more erodible than cohesive materials in terms of ability to withstand extended periods of overtopping without destruction. The attempt to evaluate appropriateness of two-versus three-dimensional embankment modeling was inconclusive because of the interaction of the two-dimensional models with the boundaries. The study did confirm that zoned embankment structures, once compromised, are much more erodible and susceptible to destruction than homogeneous structures. (fr)