5/25/22 AEG Event about Glauconitic Sand

DINNER MEETING ANNOUNCEMENT

Glauconitic Sand: A New Geohazard for Offshore Wind?

Wednesday, May 25, 2022

At the Clarion Hotel in Somerset, New Jersey
(Remote attendance option through Microsoft Teams)

Zack Westgate, PhD, PE, University of Massachusetts, Amherst
 


    
 

This meeting is available for sponsorship!
Contact our secretary or treasurer to sponsor!
 

ABSTRACT
Glauconitic sand, otherwise known as 'greensand', is a challenging soil type that can pose significant risk to foundation installation and performance. This is due to its tendency to transform from a stiff, high permeability coarse-grained material to a weak, low permeability fine-grained material due to particle crushing.  Glauconite is an iron potassium mica with a characteristically green color, often found in peloidal form. It forms under reducing conditions within shallow marine depositional environments and has been found in coastal regions of the USA including locations along the Atlantic outer continental shelf associated with offshore wind farm developments.  Due to its friable nature, glauconite affects the geotechnical properties of the sediments in which it forms.  Geotechnical laboratory tests performed on glauconitic sand samples reveal a wide range in particle size gradation, low particle crushing strength, high specific gravity and variable cementation. Intact glauconitic sand exhibits high strength, but under moderate disturbance it is relatively brittle, similar to carbonate sediments found in tropical regions.  Given its tendency to crush, in situ testing with cone penetrometers produces high tip resistance and high sleeve friction, limiting the usefulness of standard soil classification charts. This talk presents a review of the geological basis for glauconitic sand formation, describes its depositional environment and maturation process, and presents examples of its geotechnical characteristics.  Insights into the impact of glauconitic sands on offshore foundation installation and performance are discussed.

BIOGRAPHY
Dr. Zack Westgate is an Associate Professor of Civil Engineering at the University of Massachusetts, Amherst.  He received his doctorate from the University of Western Australia, and his master's degree from UMass Amherst, both in geotechnical engineering.  Zack has over 15 years' experience as a consulting engineer and manager for multidisciplinary design firms, geotechnical contractors, and specialist consultancies in the marine energy industry, and is currently a consultant at the Norwegian Geotechnical Institute.  His experience and research interests include offshore geotechnics, foundation engineering, pipeline/riser/cable-seabed interaction, experimental methods, and soil-interface mechanics.  He is an active member of both the SUT OSIG and MRE committees and serves on technical committees related to offshore wind and pipeline/riser standards development. He is a registered Professional Engineer in several states.