The influence of partial soil saturation on pile behaviour

Abstract

Finite element analyses of geotechnical problems that involve partially saturated soils are commonly carried out using conventional fully saturated soil models. Such models, however, cannot successfully reproduce partially saturated soil behaviour. This paper investigates the influence of partial soil saturation on the behaviour of piles. A total stress constitutive model for partially saturated soils has been developed and implemented into the Imperial College finite element Program (ICFEP). This model, which is presented here, was used to perform a series of single pile analyses. The results of these analyses show the effect of partial saturation and in particular of fluctuations of the groundwater table on the behaviour of single piles. The effects of a rising groundwater table on pile behaviour are also investigated in the case of a pile foundation of a high-rise building in London. The paper indicates where prediction of pile capacity and displacement under different load and groundwater table fluctuations may be very different when using fully or partially saturated constitutive models.