Two retaining walls were required at the sides of the entrance to Nicholls Lane housing development. While a Geogrid Reinforced Backfill method was appropriate for the Secura Grand retaining wall on the righthand side of the development, the retaining wall on the left was met with the challenges of limited space and existing services.
The highway boundary limited the amount of space available to construct the retaining wall on the left-hand side. The existing services present within the retained soil caused further complexities. On this occasion, minimising excavation was crucial due to the services within the retained soil.
Efficient use of land was vital as the Secura wall didn’t have the room at the back for geogrid or for no-fines concrete backfill. It was therefore desirable that both walls at the sides of the entrance looked the same despite their different conditions.
The challenge of limited space and existing services were overcome by installing Tobermore’s Secura Grand using the geopin method. Geopins reinforced the existing soil and did not require the retained mass to be excavated and replaced as with geogrid reinforcement.
The geopin reinforced secura wall is ideal for use on sites where backfill space is limited or where it is preferable to avoid the greater amount of excavation which is required for a geogrid reinforced or concrete backfill wall.
As the location of the services was identified, 50 geopins were installed without disturbing the services.
The groundworkers were pleased to discover the wall which was 3.2 metres at its highest, was quicker to construct with geopins compared to geogrid as placement and compaction of layers of fill is avoided.
Secura Grand enabled two adjacent walls with a consistent look despite the different construction methods and ground stabilisation for each case.
Tobermore also provided fully indemnified permeable paving using Hydropave Tegula Duo complemented with kerbing.
Phil Harrison, Site Manager at Chamberlain Developments, commented: ‘Our Tobermore sales representative was always available for questions and supported the works from start to finish. We gladly availed of the free design service and technical guidance from Tobermore for both the Secura Wall and Permeable Paving systems. Not only was the secura retaining wall system approved by the council without any issues, it also proved to be cost-effective and looks fantastic.’
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