While significant improvements have been made over the years in terms of tunnel construction in the USA, the substantial growth in passenger traffic, and the need for more efficient rapid transit systems in urban areas will involve a steady progress in the tunnel construction practices. In this report, an effort has been made to examine and evaluate the current tunnel construction technologies in three different mediums namely soil, rock and water. The construction technology in soil medium includes the New Austrian Tunneling Method (NATM) and Tunnel Boring Machine (TBM) method, the rock medium construction technologies include the Drilling and Blasting (D& B) method and TBM, and the water medium construction technologies include the shielded construction and immersed tunnel methods. 

The report discusses various support types for the stability of the tunnel face, both temporary and permanent methods, such as shotcreting and segmental lining. Furthermore, several case studies of various tunnel construction technologies have been examined and presented in a simple approach. Comparisons are drawn between diverse tunnel construction methods presenting their merits and de-merit which assists in analyzing and optimizing the suitable method to be adopted for a particular project.

Safety is a prime concern in tunneling and therefore a chapter is dedicated completely to discuss the safety issues of relevance during and after the construction of tunnels. A table giving information about some tunneling contractors, tunneling consultants and tunneling machinery manufacturers helps to demonstrate the capabilities and services offered. A discussion of important projects undertaken by some consultancies and contractors, along with an examination of the products of equipment manufacturers provides more details.