Sydney Trains choose Global Synthetics for emergency landslip remediation

PROBLEM

During February 2020, the greater Sydney metropolitan area received nearly 400mm of rain over just four days. For a city that usually averages just 117mm for the entirety of February, this influx caused widespread flooding and a host of emergency situations across the CBD, coastal areas and inland. The 1 in 100-year storm event caused a volume and intensity of rain and wind that was so severe that landslips were prevalent across vital transport corridors.

Two of these landslips caused disruption to Sydney’s North Shore train line, with changed conditions inside the transport corridor near Pymble and Artarmon stations disrupting travel for thousands of passengers.

An emergency fix was required, and geotechnical engineers from Sydney Trains utilised Global Synthetics' vast range of products to offer a fast and effective solution to help secure the soil and get the critical North Shore transport network back up and running.

SOLUTION

Global Synthetics offered technical knowledge and support combined with a fit-for-purpose product range. This was key to expediting repairs, allowing vital transport connections to be re-established quickly.

For this situation, Global Synthetics supplied a combination of an impermeable polyethylene liner, joined with bituminous tape and secured with specialist continuous geotextile silt tubes. This solution combined to remediate the two landslips quickly and effectively.

Firstly, ProLiner® SuperFlex LLDPE Geomembrane was selected to cover and cap the area. ProLiner is a linear low density polyethylene membrane that provides an economical alternative to traditional containment methods. This impermeable liner was selected for its strength, durability and overall ease of handling.  In addition to its impervious function, it is easy to handle, install and extremely cost-effective.

In addition, Flexi-Seal Joint tape provided a complete seal at the joints for the ProLiner SuperFlex LLDPE geomembrane. This self-adhesive, bituminous tape provides fast and effective sealing.

Finally, Geofirma AS Silt Tubes were used instead of traditional sandbags to weigh down the geomembrane. These were chosen due to their strength, durability and flexibility in length.  Geofirma® AS Silt Tubes are essentially a high UV stable, sandbag available in continuous lengths up to 50 metres long. They can be customised to suit your project with the final required length up to the user based on site-specific requirements/function.

RESULTS

The solution using a combination of ProLiner, FlexiSeal and Silt Tube performed extremely well in this demanding environment. The successful installation has cemented this system as the ideal choice for future repair and rectification works under similar environmental conditions.

PRODUCTS USED

• 1mm ProLiner SuperFlex LLDPE Geomembrane

• Flexi-Seal Joint Tape

• Geofirma Nonwoven Silt Tube

For further information on this project or the products applied please contact tricao@globalsynthetics.com.au