Shaft Behavior of a Model Pile in Plastic Empire Clays

New challenges in offshore work have stimulated research in the analysis and design of friction piles. While different concepts have been presented over the last few years for analyzing the behavior of pile shafts, there is a dearth of reliable published field measurements for evaluation of these predictive capabilities. This paper presents results of an experimental program which evaluates the conditions of a large scale pile load test. Extensive laboratory and in situ Piezocone tests emphasize the need to establish careful estimates of the initial in situ conditions and soil properties which exist prior to pile installatibn. Uncertainties associated with these parameters affect the accuracy of predictions arid hinder the extrapolation of results and experiences acquired at a given site to other deposits. Field measurements obtained with the Piezo-Lateral Stress (PLS) cell, an instrumented model pile shaft, provide valuable information regarding the variation of stresses and pore pressures acting on pile shafts throughout the various stages of a pile history from installation to loading. The PLS cell data identity important factors that affect pile shaft behavior and require control during pile load tests.