MIRAGRID® GX – Uniaxial PET Reinforcement Geogrid

MIRAGRID® GX uniaxial geogrid is a knitted polyester reinforcement geogrid manufactured by Solmax, made from high tenacity polyester yarns covered with a black polymeric coating. Solmax describes the range as providing high tensile strength with low creep characteristics, suitable for short and long term soil reinforcement applications.

Low creep is the property that matters most in permanent works. A reinforced soil wall or steep slope has to hold its geometry for decades under constant load, so the geogrid must resist stretching over time, not just survive a short tensile test. That is why high tenacity polyester with a protective coating is the usual choice for structural reinforcement, while stabilisation geogrids for subgrades are a different product family.

Uniaxial means the strength is concentrated in the roll direction, which is the direction reinforcement layers run back into the fill. Typical applications are reinforced soil retaining walls and bridge abutments, steep reinforced slopes, embankments over soft ground and basal reinforcement, landfill and mine waste slopes, and widening works where new fill must be tied into existing ground.

GX 80/30 is the grade most often specified in South Africa, and we hold it in depth. It develops 84 kN/m in the machine direction (80 kN/m minimum at the 95% confidence level), with 15 kN/m at 2% strain, 19 kN/m at 3% and 27 kN/m at 5%, on a 5.2 m × 100 m roll weighing 178 kg. The full uniaxial range runs from GX 35/20 at 38 kN/m to GX 200/30 at 210 kN/m, and every grade is available to order. Biaxial MIRAGRID GX grades are available for subgrade stabilisation and base reinforcement.

Designers work from the low-strain values, because a reinforced structure performs at working strain rather than at break. Across the uniaxial range, strength at 2% strain rises from 7 kN/m to 33 kN/m, and at 5% strain from 13 kN/m to 59 kN/m. For long term design strength, friction behaviour and reduction factors for creep, installation damage and durability, we obtain the certified data directly from Solmax for your project.

On site, MIRAGRID GX is laid on a levelled, compacted subgrade with the reinforcement as perpendicular as possible to the sloped face, unless the design says otherwise. Where a nonwoven is used with it, the nonwoven goes underneath in contact with the fine-grained material, so the geogrid sits in direct contact with the coarser fill. Panels are joined by overlapping or sewing, with a transverse overlap of typically 200 mm at panel junctions unless specified. Driving directly on the geogrid is not allowed: fill is back dumped from trucks running on previously compacted fill, to a minimum thickness of 40 cm, or 30 cm after compaction.

Solmax is not a design or engineering professional and does not determine whether the product suits a particular project, so the reinforced soil design remains with your geotechnical engineer. Geosynthetics Africa supplies MIRAGRID GX as a Solmax partner, with delivery to over 30 countries across Africa and installation by our own crews.

MIRAGRID® is a registered trademark of Solmax.