Applications Civil engineering Slope stabilisation

Geosynthetics in slope stabilisation

BOESCHUNGSSICHERUNG

Secugrid® reinforcing geogrid products are commonly used to stabilise steep slope soil veneers. Secumat® erosion control mats are used on slopes to prevent soil erosion, as well as vegetation or seed wash-out due to rainfall. In either case, Secugrid® and Secumat® geosynthetic products can be effectively used to help protect slopes from erosion and veneer failure.

Stability

It is common to design slopes as steep as possible to optimise land use. This can lead to a larger crest area or a reduction of the embankment area. If the frictional and strength characteristics of the soil cannot provide a stable structure, special reinforcing measures are required. Secugrid® geogrids are an economical alternative to modifying the slope geometry. Made from extruded high strength monolithic flat polyester PET or polypropylene PP bars, Secugrid® reinforces the soil structure by carrying excess slope forces.

With the optimised Secugrid® product design, the flat Secugrid® bars have maximum interlocking with the surrounding soil. The junction stiffness and negligible product construction elongation of Secugrid® allows immediate force absorption when confining stress is applied. Compared to other geosynthetic reinforcement products, Secugrid® geogrids show a steeper increase in the force-elongation diagram. Higher stress absorption and lower product elongation result in more economical construction methods.

Different national guidelines for slope stability calculations can be used. The NAUE Secugrid® Design Manual also contains design and product selection guidelines for proper use of the Secugrid® geogrid products. These include guidelines for the application of geotextiles and geogrids in the construction of roads, and recommendations for geosynthetic reinforcement.

The PET and PP resin used in Secugrid® provides excellent physical characteristics and helps to allow more economical product selections. Secugrid® can withstand higher long-term creep stresses than other polyolefin products due to the unique manufacturing process.

Erosion control

On slopes, especially with fine grained soils, heavy precipitation may erode surface soils. Greater erosion and ruts can occur if the slope is poorly vegetated. Geosynthetic erosion control mats are commonly used to address difficult, erosion prone slope conditions.

Secumat® erosion control mat can significantly reduce soil wash-out during the heavy rainfalls common to Middle Europe. The three-dimensional, irregular labyrinth-like structure of Secumat® is designed to allow both fine grained and gravel soils to fill the open convoluted structure. The irregular Secumat® structure holds the soil in position on steeper slopes and provides the structural support to the vegetation during the early stages of plant growth.

The use of high quality polypropylene (PP) resins make Secumat® resistant to naturally occurring soil chemicals, soil microorganisms and UV-radiation. When used in conjunction with a carrier nonwoven geotextile, the structure of the Secumat® erosion control product is virtually identical to the Secudrain® drainage system. Installed with the convoluting surface side-up, it will then perform two functions - separation and erosion control.

Conclusion

Secugrid® geogrids ensure the stability of noise barriers and retention basins, as well as dams and other steep slopes where space saving, steep embankments are often necessary.

Secumat® erosion control products are employed to prevent erosion on slopes or areas subjected to periodic turbulent flow. It prevents soil wash-out during heavy rain, and provides structural support to the vegetation - especially important during the early stages of plant growth. In drainage trenches, Secumat® also prevents soil particle wash-out, thus ensuring the proper performance of the system.

Address

  • NAUE Geosynthetics Limited
  • Genesis Centre
  • Birchwood
  • Warrington
  • WA3 7BH
  • United Kingdom
  • Tel: +44 (0)1925 810280
  • Fax: +44 (0) 1925 810284
  • email: enquiries@naue.co.uk