PSI - Issue 84

Gerardo Sorrentino et al. / Procedia Structural Integrity 84 (2026) 1071–1078

1078

Finally, the comparison between the two design approaches ( Figure 5 b) and the in-situ stresses measured using flat jacks shows that both methods overestimate in-situ stresses. This overestimation reflects the conservative design philosophy. In addition, the Kommerell method does not take into account the influence of the construction techniques of the tunnel, which in fact allow for stress relaxation in the soil before the lining is completed, while Desimon account for it only partially. In other section of the tunnel, the measured stresses are in fact much higher. 5. Conclusions This work compared two historical tunnel design approaches proposed by Kommerell (1912) and Desimon (1939). The primary distinction lies in their underlying static assumptions. In the method proposed by Kommerell, the tunnel pushes against the soil through a rotation of the sidewall at the base. Conversely, Desimon assumes that the soil loads the lining (triggered by the settlement of an equivalent loading body) and explicitly accounts for the structural contribution of the invert. Both methods were applied to a case study of a masonry tunnel built in the 1930s. The two methods yield comparable vertical loads but noticeably different horizontal loads, which are higher in Desimon’s formulation. Despite this, the resulting stress states are similar, mainly for the stabilizing role of the inverter arch. However, Kommerell’s approach implies a vertical reaction that often exceeds the soil's bearing capacity. Consequently, Desimon’s method appears conceptually more consistent for designs where the invert contribution cannot be neglected. A comparison between the computed values and in-situ stress measurements reveals that the actual stresses in the section are significantly lower than those predicted by both approaches. This discrepancy highlights the conservative nature of historical methods, which is justified by the high uncertainty and variability of soil loads inherent in the design phase. Future developments will involve benchmarking these methods with finite element method analyses, as well as incorporating direct in-situ soil stress measurements Acknowledgements This publication is part of the project PNRR-NGEU which has received funding from the MUR DM 630/2024. References Alessio, C., Attianese, G., Chiaia, B.M., Coïsson, E., Ferrari, L., Ferretti, D., Pittalis, R., Zanazzi, E., 2024a. Structural safety of existing masonry tunnel-linings: a methodology derived from existing buildings approaches, in: II Fabre Conference. Elsevier, pp. 1120–1127. https://doi.org/10.1016/j.prostr.2024.09.148 Alessio, C., Pittalis, R., Attianese, G., Chiaia, B., Ferretti, D., Zanazzi, E., Ferrari, L., Coisson, E., 2024b. Conservative rehabilitation interventions of masonry highway tunnels along the historic Genoa-Po Valley Motorway in Genoa (Italy), in: ITA-AITES World Tunnel Congress 2024. Shenzhen, China. Barla, G. Sviluppi nell’analisi progettuale delle opere in sotterraneo. Quinta Conferenza “ArrigoCroce”. Rivista Italiana di Geotecnica, 3, pp.11-67 Caquot, A., Kérisel, J. L., 1956. Traité de mécanique des sols. Corini, F., 1936. Statica dei rivestimenti delle gallerie. Rivista tecnica delle ferrovie Italiane 50. Engesser, F., 1882. F. Engesser, Ueber den Erdedruck gegen innere Stuzurunde. Deutsche Zazeitung. Falchi Delitala, G., 1971. Calcolo dei rivestimenti delle gallerie. Ed. Vitali e Ghianda, Genova (Italia). Giovannini, M., 1936. Esame critico dei metodi di calcolo per il rivestimento delle gallerie. L’ingegnere 3. Gröeger, J., 1881. Statik der Tunnelgew ӧ ble. Dominicus 1881, Prague. Heim, A., 1905. Tunnelbau und Gebirgsdruck. Vierteljahrsschrift der Naturforschenden Gesellschaft in Zürich 50, 23–134. Janssen, H.A., 1895. Zeitschr. d. Vereines deutscher Ingenieure 39. Kirsch, E., 1898. Die Theorie der Elastizität und die Bedürfnisse der Festigkeitslehre. Zeitschrift des Vereines Deutscher Ingenieure 42, 797–807. Kommerell, O., 1912. Statische Berechnung von Tunnelmauerwerk: Grundlagen und Anwendung auf die wichtigsten Belastungsfälle. Berlin: Wilhelm Ernst & Sohn. Lotti, C. R., 1958. Spinta delle terre sulle opere e gallerie. Rivista Geotecnica Italiana 4, 209. Raymond, M. Proctor, T.L.W., 1946. Rock Tunneling with Steel Supports. Ritter ,W., 1879. Statik der Tunnelgew ӧ ble. Springer. Berlin. Terzaghi, K., 1943. Theoretical soil mechanics, 1st ed. John Wilery and sons, INC., New york, London. Willmann, E. 1911, Über einige Gebirgsdruckerscheinungen in ihren Beziehungen zum Tunnelbau, Leipzig: Engelmann. Culmann, K., 1866. Die graphische statik. Verlag Con Meyer & Zeller. Zurich. Curioni, G., 1887. L’arte del fabbricare. Augusto Federico Negro Editore, Torino. Desimon, V., 1939. Costruzione delle Gallerie, 1st ed. Milano.