ABSTRACT
The fair management of Construction Time and deadlines is a key aspect of Contract Management for long and deep tunnelling Projects. Addressing geological and geotechnical uncertainties of such underground works is challenging and the need for a time adjustment mechanism has proved to be a « must-have » over the last decades, to prevent or reduce claims and disputes. While the Swiss practice is probably at the foundation of this approach, the FIDIC Emerald Book (2019) has set an internationally recognized and comprehensive approach to this mechanism. TELT, the bi-national organisation in charge of one of the World longest railways tunnels which is currently under construction and is now moving forward all along his 57km-length, has a long track-record in the implementation of time adjustment, for over 15 years. The present article reviews the implementation and progressive development of Time Adjustment in different Contracts of the TELT’s project. The completed case of Adjustment of Time Mechanism is presented for the Saint-Martin-La-Porte Exploratory Works. Two major new contracts are now ongoing, one of which is CO6/7, awarded in 2021 and spanning until 2027. This contract is EUR 1.4 billion worth and includes the implementation of 3 TBMs for a bored length of 25km, and several other excavated structures. One of the key focus of interest for the present article is the articulation of the Schedules of Baseline and the planning tools.
