Long-Term Performance of a High Rise Building Subgrade Consisting of Boston Blue Clay

The geotechnical instrumentation program implemented during construction of the Boston World Trade Center complex included the installation of thirteen multi-point heave gauges within the final subgrade of three high-rise building structures. The structures are supported in the upper portion of a 21 to 33.5 meter (70 to 110-foot) thick deposit of Boston Blue Clay. The deformation of the building subgrade was monitored prior to, during, and subsequent to the construction of each of the three structures, and the results of this monitoring are presented. The results of the multi-point heave gauge readings are discussed herein in conjunction with the phased project development and compared with the subgrade deformations anticipated through the use of empirical formulas for heave and conventional consolidation theory.