Presented August 05, 2021- Presentation Slides
“Advances in Rapid Geotechnical In-Situ Characterization of Submerged Munition Sites” by Dr. Nina Stark (SERDP Project MR18-1233)
Geomechanical properties of seafloor surface sediments affect the characterization, assessment, and management of submerged munitions sites in multiple aspects including sinkage and burial of unexploded ordnances (UXO), exposure or capping of UXOs through sediment transport processes, and interpretation of remote sensing surveying methods. The overarching goal of this work was the development of an improved framework for the deployment and data analysis of a portable free fall penetrometer (PFFP) to assist with a cost-effective and rapid characterization of submerged munitions sites. The presentation discussed the research strategy which included field surveys in areas of varying environmental conditions, laboratory testing, and the development and proof of concept of a novel investigation framework. It was found that undrained shear strength can be estimated from PFFP for muddy seafloor sediments and that friction angles and relative density can be derived from PFFP for sandy seafloor sediments. Significant variations in geomechanical properties within uppermost seabed surface layers were identified even without significant changes in sediment type. The results suggested that uppermost seabed surface layers may exhibit more suspension-like behavior than soil behavior depending on the water content. A novel PFFP strategy was formulated that enables rapid and cost-effective characterization of the upper meter of the seabed surface.
Dr. Nina Stark is an associate professor in the Charles E. Via, Jr., Department of Civil and Environmental Engineering at Virginia Polytechnic Institute and State University in Blacksburg. Dr. Stark’s current areas of research focus on the in-situ geotechnical characterization of riverine, estuarine, coastal, and seafloor sediments; the correlation of geotechnical sediment properties and remotely sensed seabed and coastal sediment responses; coastal sediment trafficability; geotechnical aspects of coastal erosion; and geotechnical reconnaissance after coastal extreme events. She has received the CAREER award from the National Sciences Foundation and the Young Investigator Award from the Office of Naval Research. Dr. Stark has authored more than 20 peer-reviewed research papers including several on the development of novel geotechnical site investigation methods relevant for naval applications. She earned her master’s degree in geophysics from the Westphalian Wilhelms University in Muenster, Germany, and her doctoral degree in marine geotechnics from MARUM-Center for Marine and Environmental Sciences at the University of Bremen, also in Germany.