REINFORCED SOIL WALLS

For taller or more critical walls, Keystone units are combined with soil reinforcement options (such as geogrids, geotextiles, anchors or galvanized steel grid reinforcing) to create larger composite structures. With this properly designed combination, the reinforced soil mass can support greater earth pressure and surcharge loads. These composite structures have permitted the construction of retaining wall structures over 50' (15 m) high. Call your Keystone Representative to see which option will work best for your project.

GEOGRID

Since the early 1980's, geogrids have proven successful in providing durable soil reinforcement for the retaining wall industry. Proper design methodology today incorporates the laboratory tested connected strength of concrete units and geogrid in all reinforced retaining wall systems. Geogrids are made from High Density Polyethylene or high tenacity polyester yarns.

Key properties of geogrid include:

• High tensile strength
• Long-term creep resistance
• Open geometry for interlock
• Non-degradable
• "Off-the-shelf" availability

The advantages of geogrid reinforced structures include:

• Economical construction by utilizing a wider range of site soils for the reinforced fill zone, minimizing the need to import select fill
• Construct walls faster without waiting for shop drawings, forming, steel placement and curing time of site cast concrete; the wall structure and backfill are constructed at the same time
• Eliminates the need for deep structural footing and excavation due to flexible vs. rigid structure system
• Provides durability; long term performance resists effects of water, micro-organisms, alkali or acidic soils

REINFORCEMENT OPTIONS

Other reinforcement options include use of high strength geotextile fabrics, composed of woven polyester yarns or films, and galvanized steel grid systems which are designed in accordance with AASHTO methods. (Steel grids are primarily used in Department of Transportation applications, but can provide cost-effective reinforcement when select fill [free draining] is available.) When use of soil reinforcement is limited due to excavation constraints, another method of retaining the soil mass is by means of anchors. Keystone units can be attached to the anchors using a short span of geogrid or direct tie method. The anchors are driven or augered into the soil to create an anchor tie back to the soil mass.