Design and Performance of the Imperial College Instrumented Pile

This paper describes the design, calibration, and field performance of a number of new instruments that have been used for research into the behavior of displacement piles in clays and sand. The instruments include axial load cells, surface stress transducers, and pore pressure probes. The special features of the surface stress transducers and pore pressure probes are described in detail, and problems associated with measuring pore pressures in strongly dilating soils are discussed. Data recorded at a stiff clay site are used to demonstrate the reliability of measurements obtained with the new instruments.