Behavior of Vibro‐Driven Piles in Sand

Abstract

Methods available for estimating the bearing capacity of piles installed with vibratory drivers are inadequate and do not explicitly incorporate important variables, such as soil parameters and in situ stresses. The influence of relative density (65% and 90%), particle size (0.2 mm and 1.2 mm), and in situ horizontal stress (10 psi and 20 psi) on the load‐movement relationship and bearing capacity of vibro‐driven displacement piles in sand is investigated using a large‐scale laboratory testing system. The test results indicate that, among the variables investigated, the most important parameter influencing the rate of penetration and the bearing capacity of the vibro‐driven piles is the initial relative density of sand deposit. Based on pile capacity tests and analytical study, several models are proposed to predict the nonlinear unit load‐transfer curves, load‐movement relationships and bearing capacity of vibro‐driven displacement piles. The model parameters are related to the important test variables investigated in this study. The model predictions are in agreement with the experimental results. Performance of vibro‐driven piles is compared with that of impact‐driven piles.