Shaft Resistance of Single Vertical and Batter Piles Driven in Sand

Abstract

An experimental investigation of the shaft resistance of single vertical and batter piles pushed into sand was conducted. A prototype laboratory setup was designed for testing relatively large model piles, inclined at an angle that varied between zero and 30° with the vertical. Two model piles having diameters of 38 and 76 mm were tested at a ratio of the pile’s length to diameter up to 40, and subjected to axial compression loading. The pile models were instrumented to allow direct measurements of the shaft resistance. A theoretical model was developed to take into account the asymmetrical earth pressure distribution around the pile shaft, the level of mobilization of the angle of friction between the pile shaft and the sand, and the pile diameter. The results predicted by the theory developed agreed well with the experimental results of the present investigation as well as other experimental and field results available in the literature. Design charts are presented for use in practice. The results of the present investigation support the concept of the critical depth for the shaft resistance of vertical and batter piles driven in sand.