Numerical Evaluation and Probabilistic Calibration of Constitutive Models for Tunnelling in Weak Rock Masses: A Case Study from the Honaz Tunnel, Türkiye

Numerical Evaluation and Probabilistic Calibration of Constitutive Models for Tunnelling in Weak Rock Masses: A Case Study from the Honaz Tunnel, Türkiye | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Numerical Evaluation and Probabilistic Calibration of Constitutive Models for Tunnelling in Weak Rock Masses: A Case Study from the Honaz Tunnel, Türkiye Ertuğrul Karakaplan, Devrim Alkaya This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8340182/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract This study evaluates the mechanical behaviour of weak rock masses along the Honaz Tunnel (SW Türkiye) by combining field-calibrated 2D finite-element simulations (RS2) with a probabilistic risk assessment. Three constitutive criteria — Mohr-Coulomb (MC), Hoek-Brown (HB) and Generalized Hoek-Brown (GHB) — were compared under supported excavation scenarios. Support layouts were derived from six empirical classification systems (Q, RMR, RMQR, RMi, RSR, NATM) and numerical predictions were benchmarked against in-situ convergence measurements. The MC model provided the best fit to field data (R2 = 0.94), while HB/GHB tended to overestimate deformations in the weakest units. To account for parameter uncertainty, we performed Monte Carlo simulations (45,000 runs) using an analytical elastoplastic tunnel solution implemented in MATLAB. Results indicate that shallow very-weak units show limited stress-induced convergence due to low confinement, whereas a deeper transition unit (Calcareous Quartz Schist) exhibited the highest failure probability (≈0.2%) and the lowest reliability index (β = 5.59). The findings highlight the effectiveness of a hybrid deterministic–probabilistic workflow for robust tunnel design in heterogeneous weak rock masses. Constitutive models Tunnel convergence Probabilistic risk assessment Monte Carlo simulation Weak rock masses Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 19 May, 2026 Reviewers agreed at journal 19 May, 2026 Reviewers invited by journal 08 May, 2026 Editor assigned by journal 12 Dec, 2025 Submission checks completed at journal 12 Dec, 2025 First submitted to journal 11 Dec, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8340182","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":559628908,"identity":"8e0d2415-7d14-4377-a5ce-b3b4d252c42f","order_by":0,"name":"Ertuğrul Karakaplan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+ElEQVRIiWNgGAWjYDACHhBxgIGBj4GB8QFEKIFILWwMDMwGcC0HiNTCJkGUFn6ew88+/Dhjl8fGfvZYdUHNYQZ+9hwD5o97cGuR7G0zntlzI7mYjScv7faMY4cZJHveGDAceIZbi8F5BmMGng/MiW0MOWa3edgOMxjcyAFqweMy+/Psnxn/fKhPbON/Y1bM8+8wgz0hLQa8PcbMPDcOJ7ZJ5Jgx87YBbZEgoEXizJliZpkzx4vZJN4YS8/sS+eROPOs4MAZPFr4e9I3M745Vp3Hz59j+Lngm7Ucf3vyxgcVeLTAQAKIYGZAxBMJWkbBKBgFo2AUYAAAwfRSf8esAw0AAAAASUVORK5CYII=","orcid":"","institution":"Pamukkale University","correspondingAuthor":true,"prefix":"","firstName":"Ertuğrul","middleName":"","lastName":"Karakaplan","suffix":""},{"id":559628909,"identity":"44a08af3-5de9-493a-992c-781f51ff2e19","order_by":1,"name":"Devrim Alkaya","email":"","orcid":"","institution":"Pamukkale University","correspondingAuthor":false,"prefix":"","firstName":"Devrim","middleName":"","lastName":"Alkaya","suffix":""}],"badges":[],"createdAt":"2025-12-11 21:53:30","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8340182/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8340182/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108182495,"identity":"670c04a2-3979-4a5c-8c51-9c5e59a17a42","added_by":"auto","created_at":"2026-04-30 08:59:24","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":491632,"visible":true,"origin":"","legend":"","description":"","filename":"GGEErturock.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8340182/v1_covered_516e17a5-0f31-4440-b245-9965077d9e48.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Numerical Evaluation and Probabilistic Calibration of Constitutive Models for Tunnelling in Weak Rock Masses: A Case Study from the Honaz Tunnel, Türkiye","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"geotechnical-and-geological-engineering","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"gege","sideBox":"Learn more about [Geotechnical and Geological Engineering](https://www.springer.com/journal/10706)","snPcode":"10706","submissionUrl":"https://submission.nature.com/new-submission/10706/3","title":"Geotechnical and Geological Engineering","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Constitutive models, Tunnel convergence, Probabilistic risk assessment, Monte Carlo simulation, Weak rock masses","lastPublishedDoi":"10.21203/rs.3.rs-8340182/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8340182/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"This study evaluates the mechanical behaviour of weak rock masses along the Honaz Tunnel (SW Türkiye) by combining field-calibrated 2D finite-element simulations (RS2) with a probabilistic risk assessment. Three constitutive criteria — Mohr-Coulomb (MC), Hoek-Brown (HB) and Generalized Hoek-Brown (GHB) — were compared under supported excavation scenarios. Support layouts were derived from six empirical classification systems (Q, RMR, RMQR, RMi, RSR, NATM) and numerical predictions were benchmarked against in-situ convergence measurements. The MC model provided the best fit to field data (R2 = 0.94), while HB/GHB tended to overestimate deformations in the weakest units. To account for parameter uncertainty, we performed Monte Carlo simulations (45,000 runs) using an analytical elastoplastic tunnel solution implemented in MATLAB. Results indicate that shallow very-weak units show limited stress-induced convergence due to low confinement, whereas a deeper transition unit (Calcareous Quartz Schist) exhibited the highest failure probability (≈0.2%) and the lowest reliability index (β = 5.59). The findings highlight the effectiveness of a hybrid deterministic–probabilistic workflow for robust tunnel design in heterogeneous weak rock masses.","manuscriptTitle":"Numerical Evaluation and Probabilistic Calibration of Constitutive Models for Tunnelling in Weak Rock Masses: A Case Study from the Honaz Tunnel, Türkiye","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-30 03:40:59","doi":"10.21203/rs.3.rs-8340182/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-05-19T08:01:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"141720185602328229224201621091466122555","date":"2026-05-19T07:03:54+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-05-09T03:45:49+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-12-13T00:12:11+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-12-12T11:55:17+00:00","index":"","fulltext":""},{"type":"submitted","content":"Geotechnical and Geological Engineering","date":"2025-12-11T21:42:01+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"geotechnical-and-geological-engineering","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"gege","sideBox":"Learn more about [Geotechnical and Geological Engineering](https://www.springer.com/journal/10706)","snPcode":"10706","submissionUrl":"https://submission.nature.com/new-submission/10706/3","title":"Geotechnical and Geological Engineering","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"c07b53e2-cc88-439e-964c-cf3807ff1f8a","owner":[],"postedDate":"April 30th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"","date":"2026-05-19T08:01:37+00:00","index":22,"fulltext":""},{"type":"reviewerAgreed","content":"141720185602328229224201621091466122555","date":"2026-05-19T07:03:54+00:00","index":21,"fulltext":""},{"type":"reviewersInvited","content":"13","date":"2026-05-09T03:45:49+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-09T03:53:45+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-30 03:40:59","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8340182","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8340182","identity":"rs-8340182","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}