ABSTRACT
The main concern in rock tunneling is to maintain the stability of the tunnel opening with time. To this end, both external and internal support systems have been used to provide short and long term stability. Known design systems for the external supports such as steel sets, cast-in-place concrete lining, and precast liners have been described in a philosophical format.
Also discussed are important aspects of rock reinforcement, both rock bolts and rock anchors (internal support systems), with emphasis on design principles, parameters for design, and methods of installation and testing.
Several examples from USBR experience in rock reinforcement are presented in the form of case studies to signify the importance of rock reinforcement in rock tunnels.
