Empirical Correlations of Young's Modulus for Displacements of Driven Piles

The displacements of axially loaded single piles can be analyzed using a variety of techniques. One of the simplest is based on the theory of elasticity and, thus, is most useful for estimating movements in working range of loads. An advantage of this method is that it requires use of only two soil properties: Young's modulus and Poisson's ratio. Predictions are relatively insensitive to the selected values of Poisson's ratio. Values of Young's modulus are not usually obtained during a site investigation. In situ values in the free field may not be relevant for prediction of pile displacements because pile driving is likely to change the properties in critical regions right around the pile. Consequently, the most practical approach seems to be to find values of Young's modulus that cause predictions to match measurements and develop correlations with data from conventional field testing. Such analyses were performed using data from a number of pile load tests performed in California. The results are presented here.