BEHAVIOUR OF VERTICAL CUTS BY SOIL NAILING TECHNIQUES

Abstract

Rapid growth in population, industries and infrastructure development in urban areas leads to shortage of land which causes the tremendous increase in the cost of land in urban areas. Therefore, the scope of underground structures like: subways, underground storage tanks, underground parking, basements and malls are tremendously increased in the Civil Engineering construction industries. All these underground structures involve huge construction cost, time, and manpower. The underground constructions also require a special construction skills Therefore, the stability of these projects is prime importance. Some time a situation may arise, where existing methods may be costly for stabilizing the in-situ soil as in case of deep cuts or excavation, where available space may be inadequate. There are number of methods available for improving the mechanical and engineering properties of soil. Soil Nailing is one of the methods developed in recent times for in-situ stabilization of all kind of slopes. In urban areas, the technique can also be used to construct temporary or permanent retaining structures to support the ground close to neighbouring structures that are sensitive to deformation. There are three types of soil Nailing Techniques i) Grouted Nails ii) Pre-buried Nails iii) Driven Nails. In this present study, Driven Nailing Techniques have been used for studying the behaviour of vertical cuts slopes with or without surcharge in Dry and Saturated conditions. For this study large scale field tests have been carried out on six vertical faces of two pits of 6m x 6m x 4m. To know the friction factor (P) of Nails, some pull out tests were also conducted in dry as well as saturated conditions. The results obtained from the large scale field tests have been verified with Geotechnical software, GEO 4 and programme developed by Gosavi (2006). The agreement of the results obtained from the field and computed from both the developed programmes are reasonably favourable for the design of similar kind of works.