Soil Nail Walls

CJA performed the first soil nailing project in North American in 1976 and has continued to be at the forefront of innovation in geotechnical construction. Soil nailing can be used for both temporary and permanent earth retention applications, and permanent slope stabilization.

Soil nailing is an earth retention technique using grouted tension-resisting steel bars (soil nails) and shotcrete facing to stabilize a section of ground as excavation proceeds from the top down.

The first step of construction is the excavation of the “lift” from the top down to a predetermined height which is typically 4 to 6 feet below existing grade. Next, the soil nail holes are drilled at a slight inclination and the threaded steel soil nail bar is inserted and grouted in a 4 to 6 inch diameter hole to insure that the soil acts as a coherent soil mass. This is designed to act as a gravity block to resist bearing capacity failure, sliding, and global rotation.

Then, vertical water drainage strips are placed on the excavated soil face to ensure drainage and prevent build-up of hydrostatic pressures on the wall. Metal reinforcing is then installed and shotcrete is applied to the exposed soil face. Excavation then resumes for the next lift. A rod-finish is applied to the shotcrete for temporary walls. Permanent shotcrete walls often have a second layer of shotcrete applied that is typically sculpted and colored to replicate local rock formations.

Soil nail walls can offer a reduced construction time and cost savings compared to other shoring systems. CJA offers a variety of services related to soil nail walls such as design/build services, construction, permanent shotcrete facing, and shotcrete sculpting for a “natural stone” appearance.

For more information on the cost saving benefits and CJA’s expertise on soil nail walls please contact our nearest office location.