Journal of Earth Sciences and Geotechnical Engineering

Geoengineering Constraints on Foundation: Case Study from Queens, New York City, USA

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  •                                                     Abstract

    This paper deals with regional geologic information coupled with geoengineering and soil characterization aspects of a facility site to be developed by New York City Agency in Maspeth (40 43' 28" North, 73 55' 10" West), Queens. Soil and sediment samples, collected from depths close to the surface to over 60 m into the bedrock near the Maspeth site in Queens, consist of a zone of non-compact fill materials (38 m thick), underlain by a compressible peat and a partially decomposed highly plastic organic layer (liquid limit around 85) associated with calcareous clay and shell fragments (13 m thick). The presence of the shell-bearing unit close to the surface may be indicative of a buried estuarine complex in this area. In planning construction projects near waterways in older coastal cities, it is important to consider this possibility. The organic clay and peat layer were underlain by loose-to-firm glacial sand with gravels often intercalated with thin silty clay lenses. The current upper soil horizons are not sufficiently strong to withstand the required loading, which is estimated at near 1200 kips in some locations. The foundation support system will therefore have to be established in the glacial sand, possessing N (blow count) around 50 and liquid limit close to 30 (low plasticity).