Olson Engineering Webinar: Geophysical Methods for Assessment of Embankment Dams
February 23, 2021 @ 9:00 am - 10:00 am| Free
Embankment dams and levees can present problems where geophysics can help assess the current state of the structure. The most common failure mechanisms in these earthen structures are internal erosion, overtopping, and failure induced from a seismic event. Geophysical methods are most applicable to the internal erosion and seismic induced failures, while related remote sensing technologies are more applicable to the overtopping issues. Internal erosion can occur when a flow path exists from one side of the dam to the other, then as the head difference increases, more material is removed leading to an increase in the diameter of the erosion path until the dam fails. Seismic induced failures are typically tied to earthquakes. In this presentation detection of voids and internal erosion pathways by spontaneous potential (SP), electromagnetic induction, electrical resistivity tomography (ERT), and ground penetrating radar will be discussed. For assessment of seismic failure risks, crosshole seismic, downhole seismic, and multichannel analysis of surface waves (MASW) will be discussed. For assessment of overtopping failure potential, LiDAR, photogrammetry, and GPS will be briefly discussed as well as slope stability monitoring with interferometric phase radar.