ABSTRACT
Since the late 1960s, engineers in Europe, Japan and North America have been exploiting the special advantages of the technique of soil nailing.' This geotechnical engineering process comprises the in-situ reinforcement of soils and has a wide range of applications for stabilizing excavations such as are associated with deep foundations or cut and cover tunnelling schemes. It has been researched with large budgets since 1975 by collaborations of contractors, universities and government organizations. It has been the subject of international conferences, symposia and seminars since 1979, and has given rise to a rapidly expanding literature of technical papers and articles worldwide. There are abundant successful case histories to cite in a wide variety of ground conditions and applications, and 'first uses' have been reported recently in such diverse locations as South Africa,' New Zealand,3 and H ~ n g a r y . ~
11.2 Characteristic features
Soil nailing is a practical and proven technique used in constructing excavations by reinforcing the ground in-situ with relatively short, fully bonded inclusions-usually steel bars. These are introduced into the soil mass as staged excavation proceeds, and act to produce a zone of reinforced ground. This zone then performs as a homogeneous and resistant unit to support the unreinforced ground behind, in a manner similar to a conventional gravity retaining wall (Figure 1 1.1).
