ABSTRACT
Tunneling works are strongly associated with significant uncertainties and risks. Change orders occur for various reasons and almost all tunnel projects tend to change as they progress. Many of the reported problems are associated with risks related to “geo” conditions that are not managed sufficiently in the design, contractual and construction phases of the projects. In order to achieve a cost-effective and a more predictable outcome of the projects to a cost that can be estimated before the projects begin, it is essential to manage the geotechnical risks in an adequate manner.
The Observational Method is an example of effective reaction to this hazard and its application is common in “re-measurement contracts”.
This paper will provide some reflections on the potentials of the Observational Method in underground works also with reference to its use into projects according to a “lump sum” logic.
