Abstract:

When designing pile foundations, it is normal to perform a site investigation in order to quantify the physical and engineering properties of the ground.  Often, the scope of the site investigation is dictated by construction time lines and budgetary constraints, rather than on the variability of the ground.  It has been shown by a number of authors that as little as 0.04% – 0.3% of the total construction budget is spent on geotechnical investigations.  Limited site investigations have the potential to impact significantly in relation to the success or otherwise of the completed project.  These include cost over-runs, construction delays, foundation failure and overdesign.  It has been suggested that “You pay for a site investigation whether you have one or not.”

This paper examines the influence of limited site investigations on the design and performance of pile foundations.  This is achieved by carrying out 3D numerical simulations within a
Monte Carlo framework.  In this way, it is possible to determine the probabilities of pile failure and pile overdesign for a variety of site investigation scenarios and ground variabilities.  The paper provides recommendations in regards to planning appropriate site investigation strategies for a variety of ground conditions.