Influence of Geotechnical Properties on Sediment Dynamics, Erodibility, and Geomorphodynamics in Coastal Environments Based on Field Measurements

• Main Author: Brilli, Nicola Carmine
• Other Authors: Civil and Environmental Engineering, Stark, Nina, Irish, Jennifer L., Eidam, Emily F., Yerro Colom, Alba
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Virginia Tech 2023
• Subjects: Geotechnical properties; erodibility; free-fall penetrometer; field measurement techniques; beaches; Arctic nearshore environments; Arctic; Climate change
• Online Access: http://hdl.handle.net/10919/115358

Geotechnical sediment properties such as moisture content, relative density, bearing capacity, and undrained shear strength have been discussed in the context of coastal sediment dynamics. However, these properties have rarely been assessed in their respective relevance or quantitatively related to sediment transport and erodibility. Also, to date there is no framework available for collecting direct measurements of these properties for estimating initiation of motion and erosion rates. Here, it is postulated that improving the ability to measure geotechnical sediment properties in energetic foreshore environments can improve our ability to predict coastal response to climate change. Through a series of field measurements, the research presented here (1) provides a framework for conducting geotechnical measurements of beaches, (2) advances portable free fall penetrometer (PFFP) data analysis in intertidal environments through the introduction of an impact velocity dependent strain-rate correction factor, (3) relates textural and sediment strength properties derived from PFFP measurements to an erosion rate parameter and hydrodynamically driven bed-level change, and (4) uses PFFP measurements to develop a sediment classification scheme in terms of soil behavior and erosion behavior for a mixed sediment type Arctic environment. Relationships between sediment properties other than grain size, most significantly void ratio, and erodibility parameters highlight the relevance of these measurements in geomorphodynamically active sandy beach environments. For the cohesive sediments in the Arctic, undrained shear strength was also related to an erosion rate parameter, allowing for a categorical framework for erodibility classification to be developed. The cohesive framework was combined with the relationships developed for sandy sediments and used to highlight areas of active sediment transport in the context of local morphodynamic and ice gouging processes. Finally, a simple case study showed how implementing in-situ ...