In some circumstances, fine-grained subgrade soils can't achieve separation from granular layers using geogrid alone. And, using only geotextile for ground stabilization won't achieve the highest performing design. When both functions are required, finding a cost- effective solution becomes necessary.
Now, engineers and contractors can get the best of both worlds with the introduction of TriAx FilterGrid. TriAx FilterGrid merges the superior ground stabilization performance of TriAx Geogrid with the separation/filtration functions of a non-woven geotextile.
What benefits can you expect?
TriAx FilterGrid is a composite material that combines TriAx Geogrid and a non-woven geotextile to achieve ground stabilization, separation and filtration functions in a single installation step.
One of the most important geosynthetic functions, which can be accomplished using both geogrids and geotextiles, is the separation of fine-grained subgrade soils, like silts and clays, from granular layers. With proper design, a well-graded aggregate placed over a stiff, stable geogrid will function as a filter, preventing migration of fine-grained soils.
However, in some cases, filtration cannot be achieved with geogrid alone due to the combination of the gradation of the subgrade soils and the available granular material. In other cases, the designer does not have sufficient data on the subgrade soils to determine if filtration can be achieved. When faced with these issues, the best solution may be the use of a geotextile to ensure that separation is maintained.
Because fine-grained subgrades requiring separation are almost always unstable as well, the stabilization function of geogrid is also needed.
Watch our on-demand webinar, " Using Geotextiles with Geogrid." We will review the requirements for achieving separation of fine-grained soils from granular layers, including how to determine when a geotextile is needed and how to select the geotextile.
There are similar, less expensive products on the market that use different types of geogrid in their designs. However, only FilterGrid incorporates the most tested, proven, reliable, and advanced geogrid technology in the market: TriAx Geogrid. The thick rib height and high aspect ratio of TriAx geogrid allows for improved interlock of aggregate. In combination with the light lamination of the geotextile, this results in better performance compared to other geogrid composites. If aggregate does not fully strike-through the geogrid component (or the geogrid straps are on both sides of the fabric), there is very limited confinement that can take place and thus limits performance.
FilterGrid: High Profile Lamination
Biaxial (BX): Full Lamination
Fabric with Straps
TriAx’s unique structure provides a high degree of in-plane stiffness through a mechanism known as lateral restraint. Lateral restraint confines and stabilizes aggregate particles within the plane of the geogrid. The confinement offered by TriAx Geogrid improves speed of construction, reduces fill requirements, and enhances the performance and durability of these working structures over time.
The non-woven filter fabric lightly laminated to TriAx Geogrid provides separation and filtration. Fine grained subgrades, especially those consisting of low plasticity silts and clays, present separation and possibly filtration needs. Tensar’s SpectraPave Software provides tools to assess if a separator is needed. This tool is based on guidance outlined in many resource documents including those of Cadergren, Terzaghi, Peck and Mesri where piping and uniformity ratios are set based on the soil type.
Tensar delivers engineered systems that combine technology and design with our products. By utilizing Tensar’s System approach to construction, you can experience the convenience of having a supplier, design services and site support all through one team of qualified sales consultants and engineers. When you partner with Tensar you can expect:
We're proud to offer state-of-the-art design solutions – specialty solutions based on advanced technologies proven since 1982. Tested in the most challenging conditions, these comprehensive solutions save time, resources and money. They’ve become the standard by which others are measured.
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