Safety management in tunnel excavation: case study of methane risk at the Val Lemme window (Terzo Valico dei Giovi)

This thesis analyses safety management in tunnel excavation, focusing on the challenges posed by methane in underground works. After reviewing the Italian and European regulatory framework, including Legislative Decree 81/08, ATEX directives, and interregional guidelines, the study examines how these provisions are applied in practice. The Val Lemme window, part of the Terzo Valico dei Giovi high-speed railway project, serves as a case study. Detailed attention is given to methane risk assessment, tunnel classification, monitoring systems, and operational safety procedures, including the exceptional use of non-ATEX equipment. Moreover, specific case studies illustrate the practical application of these procedures, highlighting how construction activities were adapted to balance work continuity with the protection of workers in high-risk environments. The results emphasise the critical role of strict regulatory compliance, reinforced supervision, and exceptional protocols in ensuring safety in methane-prone tunnelling contexts.