Investigation of piled foundations in swelling clays

Abstract

This paper presents the results of element testing and centrifuge modelling to investigate the behaviour of piled foundations in swelling clays. The study revealed that the preparation procedure implemented, was able to retain key hydromechanical properties when compared with undisturbed specimens. Furthermore, the preparation method utilised to create an artificially ‘fissured’ fabric allowed for significant swell magnitudes to be achieved in the centrifuge within a reasonable timeframe. Centrifugetesting illustrated that, at lower magnitudes of swell, increases in lateral pressure against a pile shaft can increase shaft capacity. However, if swell is allowed to continue to large magnitudes, the effects of swellinduced softening tend to dominate, thus resulting in a reduction in shaft capacity. The effects of swellinduced softening are more prominent close to the clay surface where swell is allowed to occur more freely. However, at greater depths where swell is restricted, so too are the effects of swell-induced softening, resulting in local increases in shaft capacity at greater depths.