Case Study
A Complete Solution for Perth Subdivision
Geogrid, geotextiles and wick drains for Skippers Row
A challenging project
Located on the banks of Perth’s Swan River in the City Of Bayswater, the Skippers Row subdivision presented its developer with some unique challenges.
Having overcome barriers with development approval due to environmental impact concerns over an adjacent bird sanctuary, the stakeholder then encountered the difficulties of dealing with a site that had been a dumping ground for uncontrolled fill since the early 1980s.
How Global Synthetics helped
A range of solutions was considered and adopted after intensive geotechnical investigations of the in-situ alluvial foundation.
The foundation improvements were achieved using a range of geosynthetic materials supplied by Global Synthetics. The sequence of works proceeded as follows:
Grub and strip the entire site
Trench the perimeter to prevent compaction/vibration stresses to neighbouring properties
Placement of 400mm limestone working platform
Installation of approx 110,000 lineal metres of Global Synthetics Ceteau® wick drain at 1.0m centres
Deploy approx 50,000m2 of Combigrid® 40/40 high modulus composite geogrid to form a working platform
Place and compact approximately 200mm of gravel followed by approximately 15,000m2 of Geofirma® AS200B separation geotextile
Placement of approx 2.0m surcharge fill.
The results
Geotechnical engineers for the project determined that without wick drains, consolidation was expected to take in the order of 10-15 years, whereas the inclusion of Ceteau® wick drains enabled stripping of the surcharge after only 6 months.
The tight footprint of this site also necessitated steep batters (of the surcharge fill) to the perimeter, bordering wetlands and Swan River.
A reinforced soil wall design was adopted in order to achieve an almost vertical face using ACETex® GT300/50 high strength woven geotextile. Sacrificial woven ‘bulka bags’ were used to create a standing ‘formwork’ for the ACETex® to wrap around and return into the backfill at 700mm lifts.
A post-construction environmental assessment of the site resulted in conditional approval by the WAPC for Skippers Row to proceed with the development of building lots and allocation of public open space.
