FOR SLOPES’ SAKE Fibertex Naue Secugrid 40/40Q6 soil reinforcing biaxial geogrids are used to minimise soil deformation under tensile loads over the lifetime of the structure
Using small scale nonwoven geosynthetic sand container (GSC) bags is a user-friendly method for less critical soil-retention applications, says geosynthetic product manufacturer Fibertex South Africa.
“Fibertex staple fibre nonwoven geotextiles – manufactured from ultraviolet (UV) stabilised virgin polypropylene (PP) or recycled polyester fibres – are gaining popularity in landscaping and building,” says Fibertex technical, research and development manager Gerard Dirks.
The requirement for smaller bags that are easier to fill and place originated from the landscaping industry, which required a cost-effective alternative to conventional earth-retention systems, where the function of the smaller GSC bags was to offer a simple, yet stable, soil retention solution.
“When using larger GSC bags in landscaping applications, it is difficult to place the bags without using construction equipment. It is also often difficult to establish vegetation on slopes,” notes Dirks.
In comparison, using smaller Fibertex GSC bags allows for vegetation to be established on top using a soil cover in between or even inside the GSC bags if a double layer is used.
“In cases where a lateral earth-retention design is required to take a surcharge load on top of the slope, such as a building foundation or a swimming pool, it is critical that the engineer design the lateral earth retention system for this purpose, in which case additional soil reinforcing (within the soil body of the slope) will be required.”
However, using GSC bags alone is not a replacement for an engineered lateral earth retention system, Dirks warns.
Meanwhile, Fibertex will supply GSC bags to the Palm Lakes Estate in Umhlanga, KwaZulu-Natal, for construction services provider William Brothers Builders (WBB) this month. The estate requires the bags for landscaping and erosion control to ensure vegetation growth on slopes.
WBB selected Fibertex GSC bags, owing to their lightweight, durable and cost- effective alternative to less critical slope protection and earth-retention applications.
Moreover, Fibertex has been involved in the development of large-scale marine protection GSC bags since 2010. The development of the smaller Fibertex GSC bags started in 2012.
“The company’s first project was at Lake Michelle in Noordhoek, in the Western Cape, which required lake shore protection. The smaller Fibertex GSC bags proved to be a simple and cost-effective solution to combat the medium-sized wave attacks in this coastal lake environment,” he highlights.
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Fibertex recommends that in situ soil conditions, wall/slope height and face angle, surcharge on top of the wall and slope, and type of vegetation above the wall and on the slope be taken into account when planning and designing a landscaping structure using Fibertex’s nonwoven GSC bags as the facing component to a lateral earth-retention system.