Guidelines for the Design and Construction of Conventional Tunnelling in Urban Setting
Synopsis:
Conventional tunnelling, defined as a cyclic excavation followed by the sequential installation of temporary support such as NATM, SEM, SCL, etc., has become a preferred method in urban areas to construct complex underground structures such as metro stations, multi-track metro lines, rail crossovers, short road tunnels, underground road ramps, etc. in order to avoid cut -and cover construction with its impacts on streets, traffic, utilities, businesses and the public. Under these conditions and where complex and challenging ground conditions exist, underground construction requires a flexible and adaptable design that can be executed effectively and safely while minimising impacts on existing infrastructure and the public. This specifically includes tunnelling in running and flowing ground; tunnelling under high water pressure; tunnelling in mixed-face ground conditions, with low ground cover, with the presence of boulders, abandoned foundations or unchartered utilities; near sensitive buildings and structures within the influence zone of the excavation; and in complex geometrical configurations. The Conventional Tunnelling method minimises construction impacts, reducing disruption to everyday life. Urban settings provide a host of challenges for tunnelling and underground construction that require a risk-managed approach from the very beginning of the design process through construction. The purpose of this report is to provide guidelines and recommendations to owners, designers and constructors, as well as other project stakeholders, for dealing with the challenges of using Conventional Tunnelling in urban areas in a safe and efficient manner.
2026 World Tunnel Congress Conference Proceedings
ITA Report no 39 – ITA Working Group 19 Conventional Tunnelling
May 17 – 21, 2026, Montreal, Canada (Munfah, N., Gall, V., Bilfinger W., Cassani G., Davilla, J., Galler, R., Garin, E., Heinz, H., Mitsuo, J., Oliveira, D., Sierra, M., Srb, M., Subrin, D.)
Copyright holds the International Tunnelling and Underground Space Association (ITA).