Preliminary Investigations and the Financial Sustainability of Underground Project

Tunnels upgrade connectivity and mobility, with an all-out venture cost that mostly depends on the financial support given by significant lenders. Financial sustainability is related to Risk and Sensitivity Analysis, which in turn depends the level of knowledge of the geology of the project site. The target of this paper is twofold: depict the cycle of i) a well define comprehension of the geo-related model and ii) represent the impact of geo-related uncertainties into the Risk and Sensitivity Analysis. Key elements for assessing the economic sustainability of the investment are here outlined. The undeniable degree of financing preliminary investigations because of high forthright expenses is regular for the vast majority of the underground and tunnel projects. However, there are additional risks such as the geological uncertainty mainly related to the robustness of the preliminary investigations. Significant investment is needed prior to arriving at solid comprehension of the geological model and the connected hazards. Geological uncertainties can be characterized into two significant classes: epistemic and aleatory. Fundamental investigations are normally scant and don't cover the epistemic vulnerability related to the chosen tunnel alignment or underground facility location. For an underground infrastructure project, the geological uncertainty exerts the highest impact on the project and financial sustainability. Variables must be surveyed and contrasted with the assessed cost in order the project being eligible to some kind of financing. Depending on the result of the risk analysis, solutions can differ: i) withdrawal from the project or restructuration, ii) chances ensures, iii) dividing the risks between parties and phases, and more significant, iv) a powerful undertaking readiness. Last option being the most efficient method for risk mitigation however depends on fundamental examination by specialists. Blended finance presents a risk sharing approach.