General Information
Geogrid reinforced walls are gravity retaining walls with an expanded width (commonly known as “Reinforced Fill Zone”) created by the placement of geogrid behind a column of segmental facing units. The combination of segmental units and geosynthetic layers act together creating a coherent mass to resist the destabilizing forces generated by the retained soil and applied surcharge loadings.
Geogrid reinforced walls should be designed in accordance with local Australian Standards (AS4678) and are designed for the failure modes stated in the list to the right.
The other main considerations of prime importance is drainage within and around the structures and most importantly that the walls are constructed the correct way, paying careful attention to compaction, placement and orientation of geogrids. Again Retaining Solutions has this expertise in-house.
Essentially geogrid reinforced walls, due to their relatively low material and installation costs typically save 25 to 50% compared with conventional concrete retaining walls when above 2m in height. Again such costs are project specific and project specific constraints may dictate the type of retaining solution adopted.
There are a variety of segmental block/geogrid combinations available in the marketplace. Each and every combination has unique connection strength & interface shear strength properties. These properties directly control the internal stability of geogrid reinforced segmental walls. Segmental block/geogrid combinations with poor connection strengths will inherently produce designs utilising more layers of geogrid (i.e reduced vertical spacing between layers).
The properties of the geogrid reinforcing elements play an important role in producing cost-effective designs. Commercially available geogrids are polyester (PET), high density polyethylene (HDPE), polypropylene (PP) or steel (strips, mesh panels or ladders, refer steel reinforced walls section). Refer photos below illustrating the types of geosynthetic geogrids and segmental block combinations Retaining Solutions are familiar with both from design & construction.
Geogrid Types
Polyester - PET
High Density Polyethylene - HDPE
Segmental Block / Geogrid Combinations
Vertical / Polyester
Landmark / Polyester - Unique positiive connection
Keystone / HDPE
Allanblock / Polyester
Keystone / Polyester
Rockwood / Polyester
Failure Modes
- External Stability
- Sliding overturning and bearing pressure assessment
- Global Stability for short & long term conditions
- Internal Stability
- Geogrid tensile overstress
- Pullout of reinforcement
- Internal sliding
- Segmental block stability
- Connection Strength
- Interface sheer strength
- Resistance to bulging
Applications
- Landscaping Walls
- Car parking area support
- Approach ramps to bridge overpasses
- Waterfront structures
- Stream-training walls
- Tunnel access walls
- Waste transfer stations
- Blast/sound walls
Other Walls Like This
Featured Case Studies
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Lower Molonglo
WQCC - ACTThe Lower Molonglo project is a 4.5m high, 135m long Concrib® wall stabilising a cut embankment... Read more.
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Weakleys Drive
InterchangeThe Weakleys Drive Interchange project involved the elevation of the New England Highway over the intersection with Weakleys Drive and... Read more.
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Butu Wargun Dr
Greystanes6.8m high reinforced soil wall, 325m long retaining proposed factory approx 3m from TOW. Due to heavy vertical loadings & influence of... Read more.
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Sparks Road
Warnervale2.2m high, 100mlong cribwall was constructed adjacent to a fire access road retaining insitu cuttings at Lakes Grammer School. This design... Read more.
