Evaluation of Concrete Bored Piles Behaviour in Saturated Loose and Dense Sand During the Static Load Testing

Abstract

Diversity of construction methods is available for the installation of piles; and generally piles are classified into two main groups in terms of their installation method, including non-displacement piles and displacement piles. However, non-displacement piles such as bored piles or drilled shafts cause less disruption to adjacent soil compared to displacement piles. Knowing the behaviour of piles, the load-displacement curve has an important role during the pile load testing. In this study, firstly, the background and concepts of three different constitutive soil models including Mohr-Coulomb, Hardening Soil and Hypoplastic models are discussed. Secondly, using these soil models and finite element software PLAXIS, the load carrying capacity of a single bored pile in saturated dense and loose sand are evaluated. Finally, different factors affecting load-displacement curve including Hypoplastic model parameters are assessed. The most important aim of this study is comparing the capability of different soil models to capture the large strain behaviour observed during the static load testing. The results revealed that all three soil models indicate a reasonable correlation to each other, except when the “Intergranular Strain” concept, defined in Hypoplastic model, is activated. This paper can be useful for the practicing engineers to identify the effect of different soil models in numerical simulation of static pile load testing.