New York’s Glacial Lake Formation of Varved Silt and Clay

The principal and distinct subsoil of New York City is a varved glacial lake formation. While this formation has been considered, for many years, unsatisfactory for the support of heavy structures, laboratory testing of samples from the formation have demonstrated that it has been heavily preconsolidated. Settlement analyses have indicated that medium to high-rise structures accordingly may be supported above it with tolerable settlements. This paper presents the analyses and observations of settlement on a number of structures so supported and analyzes the conclusions derived from such observations regarding consolidation of the deposit and settlement of structures.