PSI - Issue 84

Marialorenza Vescovi et al. / Procedia Structural Integrity 84 (2026) 1063–1070

1070

(a) (c) Figure 5 (a) Vertical soil stress  T on crown as function of the x-axis from crown to sidewall; (b) Vertical soil stress  T on invert and sidewall base as a function of the z-axis from invert to sidewall; (c) Horizontal soil stress  H on crown and sidewall respect to the y-axis from the sidewall to t base to the crown. 5. Conclusions In this work, a two-tiered approach for safety assessment of historic masonry-lined tunnels was presented. The work compared the use of a non-linear finite element model for assessing safety in tunnels and a simpler graphical equilibrium method based on the approach for tunnel design proposed by Desimon in 1939. The two methods were applied to a case study section of a masonry tunnel, where a complete in-situ analyses provided information about tunnel geometry and material’s resistance. The simplified approach output was validated through numerical modeling. Validation suggested the reliability of simplified approaches for non-critical tunnel’s safety assessment conditions. Comparison of the two methods showed differences in stress and eccentricity values; the simplified approach provided higher stresses in the lining. Non-linear model represents a more complex behavior of the lining under soil pressure and provides a more uniform stress distribution. In conclusion, the two approaches described in this paper can represent an effective approach to managing masonry tunnels. The simplified approach permits a fast screening of non-critical sections and to identify critical section which require a deeper investigation by the use of a non-linear finite element analysis. Further steps in this work will regard the application of the two-tiered approach to a large number of tunnel sections to better identify the effect of construction stages and interaction between lining and soil. (b)

Acknowledgements This publication is part of the project PNRR-NGEU which has received funding from the MUR DM 630/2024.

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