In general, undisturbed ground has sufficiently high compression strength, but only low tensile and shear strength. Soil nailing is a construction technique which is applied to increase and/or maintain the stability of soil mass by installing reinforcing bars or soil nails.
The construction method of soil nailing was developed by Bauer Spezialtiefbau in the course of a research project. The latter one was supported by the German Federal Ministry of Research and Technology. The principle of soil nailing is that rod shaped reinforcements, so-called soil nails, are installed in the undisturbed soil in order to increase the tensile and shear strength. As a result a composite body is created from the existing soil mass which is comparable to a gravity retaining wall in terms of its bearing behaviour, which can take on external forces.
Soil nailing can be used to stabilise terraces, deep excavations, slope faces, to stabilise existing slopes and strained soil masses during underpinning with any wall inclination. Here, you have to differentiate between temporary and permanent stabilisation. In many applications it proved to be the only economic solution.