Scour in cohesive soils has been an obstacle for engineers and designers for quite some time because, unlike non-cohesive soils, viable erosion testing devices and well-accepted scourability guidelines have been severely lacking. This online course curated by Don Parnell, PE summarizes an advanced case study reported by the Federal Highway Administration in 2015 on the development and performance of an erosion testing device that simulates open channel flow on a small scale. Design approaches are also recommended for estimating scour for a wide range of cohesive soils. Specifically, topics covered in this online engineering course include cohesive soils, erosion testing, slaking, direct force gauge, log-law velocity profile, bed shear stress, critical shear stress, erosion rate, and more.

Learning Objectives

• Cohesive soil behavior
• Erosion testing and testing devices for cohesive soils
• Critical shear stress of conhesive soils
• Erosion rates, rate models, and estimated parameters
• The ESTD, the Moving Belt, and the direct Force Gage
• Measure of flow and bed shear stress
• Flow field, shear stress measurements
• Soil preparation and properties
• Preparing soil specimens
• Direct shear and unconfined compression test
• Slaking, the slaking mechanism, and slaking test
• Critical shear stress, USDA models, Briaud mounds, power model