DFI 2020 - Design, Construction and Design Validatin of a Sheet Pile Wall Installed with the GIKEN ECO600 in Perth Sand
Stefano Pirrello, Director – Deep Foundation Solutions Pty Ltd
Sydney, Australia, +61 0423 000 127
deepfoundationsolutions@gmail.com
Sheet pile walls are a viable and relatively economic option for both temporary and permanent solutions. However conventional installation methods are not always suitable due to noise, vibration and constrained site limitations. In hard ground conditions, such as dense sand in Perth, pre-drilling is usually carried out by auxiliary machines prior to vibrating the sheets into the designed depth. In Super Crush mode, the GIKEN ECO600 can install sheet piles in hard ground conditions due to the aid of the auger which advances ahead of them. This process allows loosening of the hard ground and installation of the sheets all in one smooth operation. This construction method, producing little or no spoil is essentially not a full displacement nor a full replacement methodology, instead it is somewhere in between (hybrid). The newly disturbed ground conditions raise questions among professionals wanting to design and estimate wall performances closer to the real behavior. A solution to addressing this design unknown is to downgrade the in-situ soil stiffness when adopting this installation methodology. This may lead to either an uneconomical design or an overestimate of the wall deflections or both.
In this document the author attempts to address some of these design unknowns discussing a design installation and estimated vs measured wall deflections for a project in Perth. CPT testing carried out before and after installation of a different wall will be also compared, as a means of assessing the soil disturbance due to the installation process. Any measured soil recovery will be also discussed and proposed back analysed soil parameters derived. Comparison of models between estimated wall performance before and after with Wallap and PLAXIS 2D will be presented.
Keywords: Sheet Piles, GIKEN ECO 600, Design, Deflections, Perth Sand, Wallap, PLAXIS 2D
