| The objective of this research is to develop tools that would improve understanding of the process of levee failure due to erosion, and reduce the risk of failure. Various overtopping quantities such as durations that represent different stages of erosion prior to the failure have been investigated to improve levee design criteria. The research is based on experimental results of steady flows on the land side of a levee. The effect of water flow on erosion has been investigated, and comparisons have been done between rills formations and erosion time for various water flow rates. The levees were modeled based on the typical levee geometries, and considering the failed levees during hurricane Katrina in 2005. Twelve physical model tests were performed at 1-g and five at high g's using a geotechnical centrifuge. The model levees did not contain a vegetated layer. The data produced over the course of the project validates the behavior predicted by numerical models, developed by other members of the research group involved with this project. The erosion was modeled physically in detail, from beginning to end, that is from the time the levee overtopped until the levee breached. Typical quantities measured as a function of time were the depth, width and volume of rills, number of junction points, shape of the rills (straight or meandering), sediment transport quantities, and finally, breach. The variety of the conducted experiments provides a valuable set of experimental data that may be useful for other researchers investigating erosion of levees, dams and embankments. Three-dimensional scanning was also used to precisely verify the calculated dimensions of initial and final computer model geometries, but did not yield interim data or measurements of the quantity of eroded soil during the tests. A Kinect device was used to scan and evaluate the volume of eroded soil, and variation of the shape of the channels as a function of time. Three-dimensional images were also obtained, and variations of the depth of the eroded channels along their length were also plotted. Based on the recorded videos and pictures taken during the tests it was discovered that the Kinect results agreed well with the physical model. The Kinect is a low cost sensor, and enabled the measurement of the rate of soil erosion, which if done at all, usually requires expensive equipment. The Kinect device was also used in the centrifuge experiments, and functioned well in the high g environment. It is believed to be the first use of a Kinect device in a centrifuge, and the device is a practical and economical sensor. The application of this method in other laboratory experiments was also investigated. |
