Design of Dredged Material Containment Area Dikes on Soft Foundations

A series of geotechnical investigations, primarily consisting of cone penetrometer tests (CPTs), have been performed on very soft marsh and foundation soils in support of the dike design for the dredged material containment areas (DMCAs) in southeastern Georgia. The CPTs and other test data from the investigations have been analyzed to provide subsurface strength profiles and evaluate strength gain with time due to consolidation of the dike material and foundation soils. This paper presents a summary of the investigations performed to date, a discussion of the data and interpretation of the shear strength profiles, and results of stability analyses performed to raise the dikes. The paper also discusses lessons learned during construction of dike raisings, including the mining and use of previously dredged sediments as dike fill material.