Embankments are an essential part of many developments, providing form, function, protection and landscaping.
To deliver this, embankment stabilisation is essential – reinforcing the resistance and stability of soils to preserve the integrity of a slope or embankment, especially around watercourses and drainage channels.
Without stabilising the slope and controlling erosion, developments for new residential areas, roads and railways or reservoirs and dams, are vulnerable to erosion from surface water runoff, especially in the early stages until vegetation is firmly established.
Loose and uncompacted topsoil, stones, or gravel are susceptible to rain, wind, water runoff meaning erosion can occur and cause the materials to displace to the bottom of the slope. If this happens to be a watercourse then silt and sediment can build up, negatively impacting the watercourse design. In extreme situations this can cause flooding and silt contamination and subsequent destabilised or shifted slopes, poor drainage, risk of damage to surrounding amenities and inevitably costly remedies and maintenance.
The use of Geosynthetic products – such as geocells, geogrids and erosion control blankets help by resisting the movement or sliding of soil by forming a structured blanket of pockets to be filled with natural or recycled materials to prevent this.
While topsoil will gain strength over time from compacting and consolidation, the benefits that geotechnical products bring to these situations offer immediate stability and support the growth of vegetation or plantings on embankments. By creating an environment for surface water to runoff slopes effectively, geocells support both embankment stabilisation and drainage solutions.
Figures 1, 2 & 3 highlight a recent project over a 3 years period from installation of products.
Figure 1 – Installation of Liner which is stopping the water soaking into the ground and the Geocell keeping the soil in place
Figure 2 – 18 months after installation
Figure 3 – 36 months after installation, vegetation is now firmly established
Developed as an alternative to traditional methods of reliance on natural materials alone, geotechnical products offer a way of helping the natural environment succeed which include:
- Stability – resisting erosion by anchoring soil while supporting the growth of vegetation
- Speed – able to be installed relatively quickly
- Flexibility – allowing for increased bearing capacity or for steeper slopes to be built
- Functionality – able to be structured to achieve aesthetic appeal
- Sustainability – offering a greener and more time and cost-effective solution.
On residential developments, particularly new housing estates, effective erosion control and embankment stabilisation will not only offer attractive landscaping but will enable surface water drainage systems to be fully functional earlier allowing landscaping works to be completed quicker to allow houses to be handed over earlier.
On infrastructure developments, such as highways, slope stability within the surface water drainage channels will be a more effective solution and can also allow for steeper embankments thus reducing the width of the drainage channel.
Which solution is right for me?
Which individual or combination of products is most effective will depend on location, project and budget. This can be advised on by experts with an understanding of the local surroundings, ground and weather conditions and seasonal timings to ensure the vegetation becomes established in a planned way for maximum benefit.
Most solutions will begin with installation of liner and geogrid/ geocell to stabilise the structure of the embankment or slope and then use either a permanent or a biodegradable solution for the face of the slope, to ensure the stability is maintained and vegetation is established.
Geocells are a 3D honeycomb-like product, made of expandable panels of high-density polymers which are then filled in multiple horizontal layers to create slope stability and can be used over the surface of the slope to enable vegetation establishment and topsoil retention to create a fixed, resistant layer for slope stability.
If filled with natural materials, geocells confine sand or soil, reducing risk of movement and anchoring upper layers of soil, creating a stable environment for vegetation to grow or aggregate to sit. If filled with aggregate geocells again reduce risk of movement but are more permeable, allowing for water infiltration where drainage is required and reducing sheet flow runoff. Both options are flexible to work at a wide range of angles, able to be stacked to give additional support or height to an embankment.
Whatever the specifications or budget, working with a trusted partner, with the experience and expertise to advise on the application and installation of optimum solutions, over and above simply supplying products, will support effective erosion control on a project.