NET DOWN ANCHOR SYSTEM CASE STUDY 2
SITA UK, Binn Farm Landfill, Scotland
SITA UK Engineers were tasked with designing a temporary capping structure on a connecting slope interphase from an existing cell into the connecting bund of a new cell. The gradient of the slope was approximately 1:2 with a total slope area of 25 260m2.
A 1mm HDPE textured membrane was chosen as the temporary capping membrane.
The main challenge facing the design engineers was how to safely and securely anchor the 1mm geomembrane against potential wind uplift and wind damage.
With a slope gradient of 1:2 across most of the area and steeper in some areas, the deployment of soil windrows was discounted, as was the placement of sandbags or tyres, with thousands of bags or tyres being required over such a vast area proving labour intensive and posing Health and Safety concerns with personnel moving bags or tyres across a steep slope.
The prospect of potential wind displacement and subsequent damage was very real as Binn Farm is an exposed site which is regularly subjected to very high wind events, and the temporary cap would be in place for 2-3 years so a proven and long lasting solution was required.
NET DOWN was chosen to provide the 25 260m2 of deployed geo-membrane with secure anchorage against potential wind displacement, and protection against harmful UV sunlight.
NET DOWN was supplied in 600cm wide x 100m rolls with each width of NET DOWN being stitched together with a double threaded stitching machine.
NET DOWN was deployed directly on top of the 1mm geomembrane, the outside edges of NET DOWN were bunded by appropriate bund material.
NET DOWN was cut around gas wells and finished to provide a tight ‘collar’ around gas infrastructure.
As well as providing the capping structure with a secure anchor against potential wind displacement, NET DOWN also afforded the below geo-membrane a 50% UV block.
A further benefit of using NET DOWN is the products drainage flow properties which added to the capping structures controlled drainage and dispersal of surface water.
An aesthetic benefit of using NET DOWN was also gained: NET DOWN is supplied in Green which provided a uniformed visual appearance and ensured the capped area blended into the adjacent environment and lessened the visual impact on local residents.
NET DOWN is UV stabilised for a minimum of 7 years ensuring the integrity and performance of the product would comfortably exceed the lifespan requirement of this particular application.
The final requirement was to install walkways for gas technicians to safely access gas infrastructure across the slope. 300gms/m2 Nonwoven Geotextile was stitched into Net Down providing safe and stable walkways between infrastructure.
Pictures of completed works:
7th February 2019
25th January 2019
22nd January 2019
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