Featuring a subtle French flair in both name and design, recently completed Le Parc Residential Estate, lies between the N1 and R101, near the centre of Paarl in the Western Cape. The landscaped, family-centric estate comprises approximately 500 turn-key built homes, surrounding an indigenous central park.
During the initial stages of construction, an investigation of the proposed access road revealed a section of clayey in-situ material that heaved excessively under the load of heavy machinery. Concluding that layerwork construction was not viable without intervention, Bigen Consulting Engineers approached Kaytech for a solution.
Substantial groundwater problems encountered in other sections of the access road were previously solved by installing a separation and drainage system consisting of a thick layer of crushed rock encapsulated within a heavy grade geotextile. However, a drainage system was not necessary for this particular section of road box cut which was dry, although still heaving under load.
After an on-site inspection together with consultants, Kaytech’s Technical Sales Engineer, Norrin Stone suggested a separation and reinforcement system consisting of RockGrid PC 100/100 geogrid with sand as fill material.
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- Conditions of box cut at inspection – Wet clayey soil
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- Exposed in-situ roadbed conditions
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- Spreading backfill onto the RockGrid® PC
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- Sandy layer on top of PC in roadbed
As a proudly South African-developed composite geotextile, RockGrid PC is manufactured in Kaytech’s dedicated facility in Atlantis, Western Cape. Due to the combination of a nonwoven geotextile and high tenacity, bi-axially orientated reinforcing polyester yarns, RockGrid PC is a unique product suitable for a variety of applications including basal strengthening, steep slope stabilisation, embankment reinforcement and foundation cushioning.
Besides the central park, this unique estate adjoining the Boland Agricultural Showgrounds will ultimately feature a multi-sports grassed oval, a skate park, tennis court, picnic areas, outdoor gym stations and a crèche catering for up to 150 children.
Exeo Khokela Civil Engineering Construction installed 3 325 m2 of RockGrid PC 100 x 100kN over the clay roadbed followed by a layer of sand as fill material. The closed aperture structure of the grid allows for inter alia the use of sand as fill material. The nonwoven geotextile component of RockGrid PC protects the reinforcement elements during the critical installation phase, while the high tensile modulus provides excellent reinforcement characteristics and minimum creep deformation outperforming all polyethylene or polypropylene grids or woven fabrics. As Norrin Stone commented, “RockGrid PC is the optimum geosynthetic soil reinforcement”.
Compared to the conventional technique of unsuitable in-situ material being excavated, transported to spoil, and subsequently replaced with rock fill, RockGrid PC provides a far more cost-effective alternative. Both consultant and contractor on this project were suitably impressed with the ease and speed of placement of RockGrid PC as well as the consequent stability exhibited by the roadbed.
With the access road fully reinforced, the phased development of Le Parc Residential Estate was able to continue unabated.
For more information on Kaytech products and systems, visit www.kaytech.co.za
