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Case Studies: Temporary Slope Stabilisation, Wastewater Treatment Works Manchester, England


As part of a Wastewater Treatment Works upgrade, a 25m x 50m storm water retention tank was to be constructed. A formation level of 14m below existing ground level required a novel approach for stabilisation of the temporary batters. Typical solutions such as a secant pile wall or sheet pile wall were not appropriate due to the lack of flexibility to avoid existing infrastructure.

Slope reinforcement during excavation using Platipus anchors (Left) & Design showing anchor installation to stabilise slope (Right)


The Designer, OGI Groundwater Specialists, proposed their Stable-Earth™ system which comprises of slope rein-forcement and erosion control using Platipus Percussion Driven Earth Anchors (PDEA®) together with groundwater management. The design approach was flexible and enabled OGI’s Engineer to adjust the placement and frequency of the Platipus anchors as necessary. The use of the PDEA® System and the OGI Stable-Earth™ system for this large-scale infrastructure project has demonstrated the viability of using cost effective materials to stabilise steep batters for temporary excavation works.

Completed temporary works with the retention tank in position

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