Sunrise Beach Slip Failure - Link Gabions

Project Background

Heavy rains hit the drought-declared Noosa region earlier this year in January with catastrophic force. A long period of dry before a storm dumping huge amounts of rain may have led to a large sinkhole opening up on the Sunshine Coast.  Slip failure due to these heavy rains and a contributing blocked stormwater pipe, caused the embankment to slip, taking out a nearby water main resulting in further high pressure water cascading down the rise and worsening the erosion.

Problem

Sand under road surfaces is prone to slipping when it becomes saturated.  Surrounding roads and footpaths had to be closed during the repair of the sink hole, which measured about three-to-four metres deep and five meters wide.

Solution

Noosa Council acknowledged that the first steps to repair included the need to stabilise the ground with and enlist a Local geotechnical engineer to formulate a further plan including: site investigation, slope stability analysis, remedial design options analysis as well as preparation of design documentation.  The Engineer was able to reuse a lot of the available sandfill by compacting this sand into the zone behind the Link gabion facing.  The sand fill was reinforced with ACEGrid® geogrid placed in horizontal layers from the gabion face back into the sand fill.  Areas adjacent to the structure that required revegetation and resistance to erosion were covered with a synthetic permanent turf reinforcement matting in Landlok® 450 supplied by Global Synthetics.

Benefits of Link Gabions:

• Local Stocking To Assist In Timely Deliveries

• Quality Product

• Range Of Wire Coating To Suit Varying Environmental Conditions

• Wide Range Of Sizes

Results

The use of Link Gabions on the face provided a flexible and porous retaining structure to retain the on site sand fill and ACEGrid® geogrid soil reinforcement kept costs low and allowed for a rapid repair to allow the road to be re-opened in a short matter of months later.