https://www.scipedia.com/wd/index.php?action=history&feed=atom&title=Calvi_2026bCalvi 2026b - Revision history2026-10-22T22:39:02ZRevision history for this page on the wikiMediaWiki 1.27.0-wmf.10https://www.scipedia.com/wd/index.php?title=Calvi_2026b&diff=334200&oldid=prevAlessandro-Calvi: Alessandro-Calvi moved page Draft Calvi 269632401 to Calvi 2026b2026-09-13T06:20:09Z<p>Alessandro-Calvi moved page <a href="/public/Draft_Calvi_269632401" class="mw-redirect" title="Draft Calvi 269632401">Draft Calvi 269632401</a> to <a href="/public/Calvi_2026b" title="Calvi 2026b">Calvi 2026b</a></p>
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</td></tr></table>Alessandro-Calvihttps://www.scipedia.com/wd/index.php?title=Calvi_2026b&diff=334199&oldid=prevAlessandro-Calvi: Created page with " == Abstract == The excavation of road and railway tunnels through inclined fractured zones represents one of the most challenging scenarios in underground engineering. The s..."2026-09-13T06:20:05Z<p>Created page with " == Abstract == The excavation of road and railway tunnels through inclined fractured zones represents one of the most challenging scenarios in underground engineering. The s..."</p>
<p><b>New page</b></p><div><br />
== Abstract ==<br />
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The excavation of road and railway tunnels through inclined fractured zones represents one of the most challenging scenarios in underground engineering. The stress state within the rock mass undergoes complex perturbations when the tunnel axis intersects fault zones, shear bands, or preexisting fracture sets at non-perpendicular angles. Drawing on the theoretical framework developed by Zoback (2010) for failure analysis of deviated wells — specifically the generalised borehole wall stress equations, drilling-induced tensile fracture (DITF) diagnostics, and shear velocity anisotropy measurements — this article extends these principles to the three-dimensional geomechanical problem of inclined tunnel excavation. A critical review of stress transformation theory, breakout analysis for inclined openings, and the role of fracture dip in governing tunnel stability is presented. On this basis, the article proposes a new geomechanical methodology: the Integrated Stress Analysis Framework for Fractured Zones (ISAF-FZ). The ISAF-FZ is a sixphase, adaptive workflow that integrates in-situ stress characterisation, fracture network analysis, inclined opening stability assessment, support design, and real-time monitoring. Application to two case studies — the Gotthard Base Tunnel and the A1 Apennine Motorway Tunnel — demonstrates the framework's predictive capacity for support pressure requirements and excavation sequencing in crossed fractured zones. The results show that fracture dip angle is a primary control on required support pressure, and that the ISAF-FZ framework reduces prediction uncertainty by up to 35% compared to conventional isotropic approaches.<br />
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== Document ==<br />
<pdf>Media:Draft_Calvi_269632401-6596-document.pdf</pdf></div>Alessandro-Calvi