Research Civil Engineer US Army Corps of Engineers Vicksburg, Mississippi
Identifying and predicting soil erodibility characteristics is a complex process critical for the effective risk management of facilities and structures susceptible to erosion such as riverbanks, bridges, levees, and dams. This information is necessary to assess whether systems are at risk of surface erosion due to flowing water. For USACE infrastructure, this information is relevant for the prediction of overtopping breach of levees and dams. Additionally, erodibility measurements of soil are used to predict scour of dam spillways, coastal shoreline movement, and riverbank migration. Reliable and economical ways to determine these erosion properties are necessary for quantitative risk assessments to appropriately manage the safety of these structures and ensure their reliable operation.
Erosion Database compiled by Texas A&M University as part of the National Cooperative Highway Research Program was assessed in this investigation. The assessment was performed to explore the possibility of reducing uncertainty in erodibility estimates by investigating a subset of the data that was reported as compacted or engineered fill, which is relevant to breach and scour prediction for levees and dams.
Much of the uncertainty was found to due to inherent variability in soil characteristics, since the -standard correlations used to predict erosion properties are derived from a database of tests mainly conducted on natural riverine sediments (e.g., intended to estimate bridge scour). These correlations may not be relevant for assessing much of the USACE built infrastructure, which are comprised of engineered fills compacted in place as opposed to naturally sedimented soil deposits.
This report presents the findings of the database assessment and provides recommendations for further research and development to improve predictions.
