The overall intent of this research is to develop numerical models of erosion of levees, dams and embankments, validated by physical models. The physical model tests are performed at 1-g and at high g's using a geotechnical centrifuge facility. The erosion is modeled in detail, from beginning to end, that is from the time the levee is overtopped until the levee is breached. Typical quantities measured as a function of time including the depth, width and volume of rills, number of junction points, rills shape (straight or meandering), sediment transport quantities, and time to breach. This data can be obtained from the numerical modeling, but is difficult to obtain from the physical tests in real life. Video images indicate that the physical modeling results which have been tested in this research agree with the numerical modeling results. A comparison has also been made between observed breaching width and the FEMA (Federal Emergency Management Agency) new levee breach formula for both 1-g and higher g's centrifuge tests. Results also show that at small water flows, seepage plays a significant roll in controlling erosion. Although long-term seepage may eventually cause failure, in the short term low flows tend to reduce erosion by reducing the amount of overtopping.
展开▼
