Geotechnical investigations at the caminada headlands beach and dune in coastal Louisiana

The Caminada Headlands is a beach and dune system near Port Fourchon in coastal Louisiana that provides natural protection for back barrier marshes against storm surges and wave overtopping. Due to significant shoreline erosion and regional subsidence, a beach and dune restoration project was initiated in 2012 to replenish the shoreline front. Because of the underlying soft deltaic sediments, this restoration effort was expected to cause significant increase in the applied vertical stress and thus sediment settlement. To quantify the degree of settlement occurring within the compressive sediment layers and the fill, extensive geotechnical investigations were conducted for design and installation of settlement plates and subsurface settlement anchors to monitor the field performance. This paper presents the geological and geotechnical investigations, measured material properties, and corresponding empirical correlations developed from fifty-one (51) laboratory consolidation tests. The pre- and post-survey elevations of the site are also used to determine the change in vertical stress with depth at the instrumented sites. The measured material properties and vertical stress profiles can be used to calibrate the numerical modeling of the sediment and fill settlements.