Creating reinforcements for steep slopes requires high tensile strength, long-term service performance, and robust soil interlock. Not all geogrids are comparable in the slope project environment, so making the right choice matters for ensuring safety and limiting project costs.
Below we outline the ideal geogrids for steep slope reinforcement and compare some of the most important materials and structures used in real-world engineering.
What Steep Slope Reinforcement Requires
Steep slopes face constant sour pressure from gravity. The burden is made worse by rain fall and slope erosion generally. As the angle steepens soil movement is ever more likely.
Reinforcement material must show strong tensile resistance, while also arriving with the capability of providing long-term helpful service.
Good soil interlock is also helpful. The geogrid should work tightly with backfill soil or aggregate.
Uniaxial Geogrid for High Strength Directional Support
A Uniaxial geogrid is one of the best materials for steep slope reinforcement. Designed to carry loads in one direction mainly, this structure affords very high high strength, roll directional tensile strength in return.
As part of a slope system, a uniaxial geogrid simply transfers soil pressures through to blanket ground layers for stable ‘discharge’.
Common materials include HDPE and PP – both offer good chemical resistance and durability in soil. High Tenacity Polyester (PET) Geogrid for Long Term Stability High tenacity polyester geogrid is 10 used extensively for permanent slope projects.These materials have good resistance against degradation under prolonged loading and so exhibit good creep resistance in most long-term-loading situations.
Largely used for soft-soil stabilization and embankment reinforcement, PET geogrid also retains strength even after long service time.
This geogrid also has good compatibility with soil and aggregates and so tends to improve bonding performance in reinforced soil structures.
It is generally used in projects requiring long design life such as highway and railway embankment applications.
Fiberglass Geogrid for Stiff ‘Slopes’
Another option for slope reinforcement, this geogrid provides a high taut tensile strength with very little elongation.
Commonly designed as an upper surface layer in stabilization efforts, fiberglass geogrid works well to mitigate cracking and surface deformation.
However, this type is better expected to use as a part of an asphalt or composite geogrid and reinforcement system than as a single predominant sub base slope structure.
Limits of Biaxial and Triaxial Geogrid in Steep Slopes
Biaxial geogrid is of strength in both directions so that is widely used in support road base reinforcement and ground stabilization.
But, for steep slope reinforcement, this is not the strongest option available. The direction of load in a slope is primarily vertical and then outwards.
A triaxial geogrid improves on this, providing better stability in multiple directions.
This type of grid has tended to perform better than the biaxial types in terms of load distribution.
However, neither biaxial nor triaxial geogrid approach the directional tensile strength speed of uniaxial geogrid, usually at homewind in the steep slope applications.
So we find this used principally in base layers and not as the main face of slope.
Coated Geogrids for Durability Performance in Rugged Environments
PVC coated geogrid and bitumen coated geogrid have also been around, providing better city protection against UV and moisture.
While these coatings improve against lifestyles aging and chemical exposure, they do offer them a longer useful life in an outdoor slopage project. Bitumen coated fiberglass geogrid is used commonly in reinforced external steep-slope asphalt or drainage-related systems.
While coating type does not change core strength direction they serveto improve durability and installation performance.