Over the years our products have been used to create some truly spectacular solutions, from the 14-metre-high reinforced soil wall at Elan Valley to the utterly breath-taking beauty of ‘The Lady of the North’ in Northumberlandia. We took a look back in the achieves to remember some of the team’s favourite and most prestigious projects!

National Trust Calke Abbey Ancient Tree – Cellweb^® TRP

‘The Old Man of Calke’ is Calke Abbey’s oldest tree and is thought to be up to 1200 years old. With the average age of large oak trees in Britain being 200 years it certainly is the ‘Old Man’ of oak trees. However, many years of constant foot traffic had caused significant increase in soil compaction beneath one side of the tree. This had resulted in reduced water and oxygen availability to roots beneath. This was reflected in the crown, which was displaying accelerated and significant die back on the footpath side. A solution needed to be found to alleviate the existing soil compaction and minimize further future compaction, ultimately preventing further die back.

Cellweb^® TRP was decided as it ensures that the loads placed upon it are laterally dissipated rather than transferred to the soil and roots below.  A 90mm layer of mulched wood chip was applied to the existing ground surface before the installation of the Cellweb^® TRP system. This was used to encourage decomposers such as earth worms to help alleviate the ground compaction and aerate the soil.

A layer of Treetex geotextile was then laid on top, acting as a separation layer and pollution control measure. Panels of Cellweb^® TRP were then laid on top of the Treetex and infilled with a clean angular stone. The Cellweb^® TRP would minimise any further compaction within the rooting environment, while decomposers would naturally aerate the ground, reducing soil bulk density. The use of Cellweb^® TRP infilled with clean angular stone would also allow the continued permeation of water and gas exchange between rooting environment and atmosphere.

For further information on Cellweb^® TRP visit – /product/cellweb-tree-root-protection

Northumberlandia – Tenax TT060, TT045, Landlok TRM450

Northumberlandia is the world’s largest human form sculpted into the landscape, designed by the renowned landscape architect and artist Charles Jencks. The woman earth sculpture is lying at the entrance of a coal surface mine in Northumberland, north of England.

The structure is 400m long and 34m high at her highest point. It takes about 20 minutes to walk the 1,162-metre-long path around the landform. In total 1.5 million tonnes of soil and clay from the surface mine were used in the creation of this sculpture. To construct the most challenging parts of the sculpture a solution was required to achieve the steep slope angles and complex shapes needed for the chin, nose, nostrils and eye brows. The design was based on a section with a maximum reinforced slope height of 6.9m, slope angle of 60 degrees and a top gabion wall height of 3.5m. The reinforced soil slopes were designed according to BS8006:10 for the internal stability and Eurocode 7 BSEN1997-1:04 for the global stability.

For the reinforcement of the slope Tenax RW TT060 and TT045 Geogrids were used with a regular spacing of 600mm, wrapped around at the face. The finished slopes were protected with Landlok TRM450 to ensure a vegetated face.  Compacted weathered mudstone with no cohesive material was used as the reinforced fill with the following parameters: Friction angle Φ = 27º C = 0, Ύ = 19kN/m3. Compacted mudstone was used as the foundation material with: Friction angle Φ = 35º, C = 0, Ύ = 20kN/m3. The main challenge during construction was control of the water content and settlement due to the large amount of rainfall. So, halfway through the project is was necessary to install a new internal drainage system within the structure, tied into the lagoons on the project. The lagoons, initially ornamental, were increased in size to take away the water and to become drainage lagoons.

For further information on Tenax Geogrids visit – /product/tenax-geogrids

Royal Hospital Chelsea – Golpla^®

The Royal Hospital Chelsea in London is a retirement and nursing home to the famous Chelsea Pensioners, some 300 veterans of the British Army. Situated on a 66-acre site, the Royal Hospital is a Grade I and II listed building and the appearance of this iconic London landmark is vitally important. As part of this upkeep it was decided that the gravel drive linking the East and West Road with Royal Hospital Road needed improvement.

With no storm drainage on site to connect to a SUDS solution that would provide high permeability was required. Percolation testing was done to determine the ground conditions, what was needed was a sub-base and surface to suit. In addition, their client wanted a product which closely matched in colour the existing golden gravel surface dressing used elsewhere on the project. The black and green grids promoted by other companies were ruled out as being too visible. Golpla^® is the only product available in a Buff colour which enabled it to blend with the chosen gravel and be more discreet. As a gravel reinforcement the build-up would work as a SUDS system and cope with the camber and cross fall onsite.

A technical recommendation for the build-up was requested which our in-house engineers were able to provide. The build-up and colour were agreed by the client in October and Willerby confirmed that they would be starting on site in January. A meeting was held at the site in January 2017 and Geosynthetics provided guidance on the best way to install the Golpla^® units and the bedding layer.

Golpla^® is proven for gravel reinforcement and was therefore able to provide the necessary reinforcement for the maintenance vehicles at the Hospital. In addition to strength and durability its range of colours made it ideally suited to this project.

More information on Golpla^® can be found here – /product/golpla-grass-gravel-reinforcement