Description:

In-situ Geotechnical Investigation of Coastal Sediments With Regards to Sediment Remobilization Processes and Sediment Stability

Abstract
Geotechnical parameters and soil behavior of coastal sediments impact sediment remobilization processes and stability. Therefore, they have the potential to be a key factor for the assessment and prediction of coastal erosion, coastal engineering activities, as well as naval applications. Most geotechnical in-situ methods have been developed for non-subaquaeous conditions or for offshore conditions with the availability of ship support. However, few field techniques have been developed for the coastal zone with strongly varying water elevations and energetic hydrodynamics, leading to a current gap in data availability and understanding of soil behavior in the intertidal and nearshore zones. This presentation provides an overview into most recent developments of portable free fall penetrometers for the in-situ characterization of surficial sediments in coastal areas, the use of wave gauges for pore pressure measurements in the coastal zone, and the use of remote sensing techniques for geotechnical characterization of beach sediments. Data examples will include results from field expeditions to the Arctic, Duck, North Carolina, Sylt, Germany, and Yakutat, Alaska, giving new insights into the relationship between soil behavior and coastal processes, but also raising new questions.

Bio
Nina Stark received her MS in Geophysics in 2007 from the University of Muenster, Germany, working with the German Naval Research Institute for Underwater Acoustics and Geophysics on mine burial prediction. In 2011, she received her PhD working on the in-situ geotechnical investigation of sediment remobilization processes at MARUM-Center for Marine and Environmental Sciences at the University of Bremen, Germany. In the framework of her PhD, she developed a novel portable free fall penetrometer that enables geotechnical seabed probing under energetic hydrodynamics, and pioneered in-situ measurements of seabed surface hardening and softening associated to active sediment remobilization processes. Nina joined Dalhousie University, Canada, as a postdoctoral fellow in 2012 after continuing some of her PhD work as a postdoctoral fellow at MARUM. During her postdoctoral appointments she focused on the development of a penetrometer for deployment from manned submersibles, seabed monitoring around offshore wind energy converters, beach dynamics and a novel acoustic Doppler device for high resolution monitoring of the seabed surface. She joined Virginia Tech as an assistant professor in 2013. Her research is focused on coastal geotechnics, coastal and marine field surveying methods, subaqueous sediment dynamics, beach trafficability, and ocean renewable energy. Nina has presented one of the keynote lectures at the 5th International Conference of Geotechnical and Geophysical Site Investigation in 2016, and has co-led teams for the Geotechnical Extreme Events Reconnaissance (GEER) association in response to Hurricanes Harvey and Irma in 2017. She has received the NSF CAREER award and the ONR Young Investigator award in 2018.