Key Elements for Keeping the Costs of Tunneling Projects under Control
Many owners are convinced that it is impossible to keep construction costs of tunneling projects under control and that additional costs that may occur are always significant. This article is based on an analysis of as-built costs for tunneling projects, in France, for these last fifteen years and shows that costs can be kept under control if some considerations in the studies and the progress of works are applied. Obviously, preliminary studies are key elements as the main characteristics of the project are setting up at this moment. Particularly, this analysis shows also that the investment in site investigations can be widely profitable when it is included in an overall risk management process. It is all the more profitable as money dedicated to site investigation is spent close to the preliminary stages. Finally, those recent data are compared to those from the study led in the '80s by USNCTT that analyzed the link between quantity of geological investigations and construction costs.