Consolidation Characteristics of the Tidal Marsh and the Varved Silt and Clay Deposits of the New Jersey Meadowlands

The New Jersey Meadowlands is roughly 20,500 acres of wetlands, uplands, and developed areas located in the Hudson, Essex, and Bergen Counties of New Jersey, about three miles to the west of New York City. The subsurface profile of the Meadowlands comprises a tidal marsh deposit of thickness ranging from 2 to 33 feet at various locations, which mostly consists of very soft peat and organic clayey silt. The tidal marsh deposit is underlain by soft to firm varved deposits of silts and clays with a thickness of about 100 feet in many locations. Since, both the tidal marsh and the varved silt and clay deposits are highly compressible, designing foundations in the Meadowlands area can be very challenging due to concerns of excessive consolidation settlements. The results of consolidation tests on undisturbed soil samples collected from a total of 17 sites throughout the Meadowlands are compiled and presented in this study. The consolidation tests were performed on 11 samples from the tidal marsh deposit and 65 samples from the varved silt and clay deposit, as part of various projects over the last six decades by AECOM USA, Inc. and its legacy companies—URS Corporation, and Woodward-Clyde-Sherard and Associates. Based on the primary and secondary consolidation parameters, consolidation settlements for a typical range of shallow foundation sizes and contact pressures are estimated using the computer program Settle3D. The bands of settlement curves presented in this paper will provide preliminary estimates of consolidation settlement and thereby assist geotechnical engineers to evaluate the feasibility of shallow foundations for structures, such as buildings, flood walls, levees, etc. in the New Jersey Meadowlands.