Using water injection to remove pile base resistance during installation
- 1 November 2014
- journal article
- Published by Canadian Science Publishing in Canadian Geotechnical Journal
- Vol. 51 (11), 1273-1283
- https://doi.org/10.1139/cgj-2013-0240
Abstract
Water injection is currently used to reduce pile installation resistance in a variety of soil conditions. However, the mechanisms governing load reduction remain unclear, and there are uncertainties over the effect of water injection on the long-term behaviour of the installed pile. This paper offers some insights based on centrifuge model tests, with the aim of clarifying the installation mechanism. A novel approach to scaling was required, and the particle size was deemed to scale with enhanced gravity. A three-stage variable permeability mechanism is proposed and validated against a series of instrumented pile installations. Various pile installations were completed using different flow rates and injection geometries to investigate the differing injection effects. Base resistance was eliminated by forming a fluidized region around the pile toe, extending to two pile radii. However, fluidization could not be maintained beyond a critical depth of installation, and base resistance increased thereafter.Keywords
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