Laboratory and In-Situ testing for the identification of bonding parameters of GFRP pipes and soil nailing systems

The soil nailing is one of the most effective provisions for the control and reduction of the tunnel pre-convergence and face extrusion and its use has become integral part of modern design methods. In the years, improvements have been introduced in the technological aspects and efforts have been made to better understand the mechanical behaviour of new materials and equipments. Some innovative technical solutions are discussed in this paper, devised to improve the reinforcing action of Glass Fiber Reinforced Polymer (GFRP) pipes and of soil nails. The effectiveness of these solutions, compared with traditional ones, is assessed on the basis of laboratory and on site pull out testing.