Design of Laterally Loaded Displacement Piles Using a Driven Pressuremeter

The nonlinear subgrade reaction method is widely used for the design of laterally loaded piles. This method replaces the soil reaction with a series of independent springs. The nonlinear behavior of the soil springs is represented by P-y curves, which relate soil reaction and pile deflection at points along the pile length. Most of the existing methods for obtaining P-y curves are highly empirical. Often little account is taken of the method of pile installation. The pressuremeter offers an almost ideal in-situ modelling tool for determining directly the P-y curves for a pile. As the pressuremeter can either be driven or self-bored into the soil, the results can be used to model either a displacement or a non-displacement pile.

The driven pressuremeter used in the study described in this paper was essentially a standard pressuremeter with a solid 60° cone shoe at the tip. The instrument was pushed into the soil. This paper provides a detailed description of the equipment, testing procedures, and the theory that enables the family of P-y curves for laterally loaded displacement piles to be obtained. A case study, using the driven pressuremeter results to predict and compare the performance of two full-scale field lateral pile load tests, is presented.