The main purpose of soil nailing is to construct a retaining wall or reinforce, strengthen and thus stabilize ground slopes providing a cost-effective retaining system for a variety of ground conditions. This is an economical technique of earth retention that has several advantages over other types of retaining structures, such as cost, adaptation to irregular shapes, method flexibility. The primary reinforcing element of this system is steel tendons or bars “nails” that are drilled into the ground and grouted. These nails increase soil cohesion through their ability to carry tensile loads.
Soil nail walls are constructed using top-down techniques where closely spaced holes are drilled into stable ground zone at a location, inclination and depth specified in the design requirements. The nails are inserted into the grouted holes. Steel reinforcement rebar mat is then laid and a first layer of shotcrete is applied leaving the soil nail head protruding so that bearing plates can be installed. After installing bearing plates and locking nuts on each soil nail head, random installations are tested and a second layer of shotcrete facing is applied thus forming the wall. In most situations a suitable drainage system is incorporated into the wall construction.