2025 Dr. David K. Crapps Lecture (student tickets only)

Speaker: Professor Jean-Louis Briaud

Topic: SOIL EROSION - FUNDAMENTALS AND APPLICATIONS

Soil erosion is a major problem worldwide including bridge scour, levee and dam overtopping, internal erosion of dams, meander migration, cliff erosion, and more. Understanding the elementary process requires a different frame of thinking in geotechnical engineering as the shear stress imposed at the boundary between the soil and the water is extremely small yet it leads to such features as the Grand Canyon. A laboratory device was developed in 1990 to study the soil erosion process at the element level. This device called the Erosion Function Apparatus or EFA gives the erosion constitutive law linking the erosion rate to the interface shear stress including the critical shear stress at which the erosion process is initiated. This erosion function is to erosion problems what the stress strain curve is to mechanical deformation problems. The erosion function is then used in numerical simulations to predict the erosion process around full scale structures such as bridge supports, river meanders and levees. Large scale experiments provide the basis for calibrating the numerical methods which in turn are used to develop design guidelines. The lecture goes from fundamentals to applications such as scour depth predictions around bridge supports and includes protection against erosion; it ends with comments about the probability of occurrence of design events and more importantly risk analysis.

Host or Publisher University of South Florida (Dr. Gray Mullins)