This Strategic Environmental Research and Development Program (SERDP) and Environmental Security Technology Certification Program (ESTCP) webinar focuses on Department of Defense-funded research efforts to advance the characterization and management of submerged munitions sites. Specifically, the principal investigator will discuss the development of an improved framework for the deployment of a portable free fall penetrometer for cost-effective and rapid characterization of submerged munitions in marine environments.
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 is 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 will discuss 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 suggest 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.