Instrumented Testing of Soft Clay Behaviors for the Savannah Container Terminal

The Georgia Ports Savannah Container Terminal is an approximately 430-acre new container terminal planned on Hutchinson Island. Hutchinson Island, located in the middle of the Savannah River, is a low-lying marshland known for weak soils and engineering challenges caused by the weak soils. The soil stratigraphy comprises 30–40 ft of very soft clays underlain by sands of variable thickness and density and stiff clay locally called the marl. The engineering challenges include large settlements, ground instability for slope and bulkheads, and down-drag loads on piles. To study the behaviors of the soft clays for the design of the planned development, we constructed two test embankments with wick drains. The instrumentation included settlement plates, settlement sensors in different strata, magnetic extensometers, standpipe piezometers, and embedded pore pressure sensors. The data from the instrumentation provides insights into the consolidation process of the soft clay layer. The paper presents the construction and instrumentation plans of the two test embankments and data from the monitoring. The field test results were used to calibrate the empirical correlations of soil compressibility and rate of consolidation from cone penetration testing (CPT) and laboratory consolidation testing.