Lessons Learnt from the SS 106 Jonica Highway Construction Works

During the construction of a new highway segment in the hilly territory of the Calabria region, in South Italy, several instability processes have been activated so delaying the works and causing a cost increase of the infrastructure. Building an infrastructure in structurally complex clayey formations, so widely spread over the entire construction area, is certainly cumbersome; the highly tectonized clayey formations can hardly be characterized and their discontinuity patterns, often masked by the complexities of the geological features, make the instability phenomena difficult to foresee through standard practice investigations. Nevertheless, the risk of instability may be minimized if design strategies that resulted successful in similar conditions are implemented. In this paper such design strategies, to be adopted for excavations and earthworks in geologically complex soil formations, will be presented and analysed in the light of their economic and environmental sustainability, through the discussion of few case studies.