ABSTRACT
In the TBM world, one of the most important key success factors is soil conditioning. While many TBM projects encounter mixed geology, the case of Mt. Etna and the volcanic geology of the Catania Metro is truly singular. Soil conditioning can change the balance of a project, that is economical and feasibility balance. Especially in EPB projects, this factor defines the rules to lead the excavation, it could enhance our performance, decrease our wear drastically and also help us make important savings. In most projects, soil conditioning parameters rarely change. These parameters follow the primary characteristics of the site´s geology. In our Catania Metro tunnel, soil conditioning has changed continuously, and we have had to adapt to the changing mixed face. The aim of this article is to show how the heterogeneous geology of Etna has been excavated and the problems found during this challenge.
