A New Classification Method of Surrounding Rock Quality for Phyllite Tunnels under the Condition of Layer Orientation Parallel to the orientation of tunnel Axis

A New Classification Method of Surrounding Rock Quality for Phyllite Tunnels under the Condition of Layer Orientation Parallel to the orientation of tunnel Axis | 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 A New Classification Method of Surrounding Rock Quality for Phyllite Tunnels under the Condition of Layer Orientation Parallel to the orientation of tunnel Axis Jing Yang, Chengfeng Wu, Rui Zeng, Ping Wang, Yupeng Lu, Hao Man, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5787047/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Surrounding rock classification is a critical factor in evaluating tunnel stability, determining construction methods, and selecting support parameters. Various engineering sectors utilize different methods for grading tunnel surrounding rock quality. The HC method iswidely adopted in the hydropower industry for this purpose. However, due to the anisotropy of layered phyllite, the classification results obtained using the HC method for phyllite tunnels—when the layer orientation is parallel to the tunnel axis-differ significantly from those based on actual field investigations. This study conducted uniaxial compression tests on rocks, revealing that layered phyllite exhibits notable anisotropy at bedding angles of 0°, 45°, and 90°. The compressive strength follows a V-shaped trend as the angle between the bedding and loading orientations changes, while the deformation modulus decreases linearly with increasing angular deviation between the loading orientation and tunnel axis. Numerical simulations were performed to observe tunnel deformation at various bedding-to-tunnel axis angles. Results showed that, as the bedding angle decreases, deformation of the tunnel wall and crown increases progressively. At angles of 0°, 30°, 45°, 60°, and 90°, the deformation ratios for the tunnel wall were 1:3.7:3:4.74:5.44:7.7, and for the tunnel crown, the ratios were 1:1.3:1.94:4.7:6.7. When the traditional HC method was used to classify the surrounding rock in tunnels with parallel phyllite layers, the agreement rate was only 13.33%, indicating low accuracy. By modifying the occurrence score for major structural joints and incorporating the weight ratios derived from numerical simulations, the HC method’s accuracy improved, achieving an agreement rate of 100%. This study enhances the precision and applicability of surrounding rock classification and offers valuable insights for tunnel construction. Surrounding rock quality classification HC method Anisotropy characteristic Phyllite tunnel Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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-5787047","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":399897091,"identity":"91824a65-b543-41b9-bc2b-0e11ecc5586c","order_by":0,"name":"Jing Yang","email":"","orcid":"","institution":"1.\tPower China Hua Dong Engineering Corporation Limited","correspondingAuthor":false,"prefix":"","firstName":"Jing","middleName":"","lastName":"Yang","suffix":""},{"id":399897094,"identity":"bf055426-fef9-490b-8d0a-1571e29477ba","order_by":1,"name":"Chengfeng Wu","email":"","orcid":"","institution":"Chengdu University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Chengfeng","middleName":"","lastName":"Wu","suffix":""},{"id":399897096,"identity":"d9ee1e86-79b4-4805-a67d-4808d9f8c5b7","order_by":2,"name":"Rui Zeng","email":"","orcid":"","institution":"Chengdu University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Rui","middleName":"","lastName":"Zeng","suffix":""},{"id":399897097,"identity":"7c8a7e8d-6fe1-4729-b439-302cf500ce36","order_by":3,"name":"Ping Wang","email":"","orcid":"","institution":"1.\tPower China Hua Dong Engineering Corporation Limited","correspondingAuthor":false,"prefix":"","firstName":"Ping","middleName":"","lastName":"Wang","suffix":""},{"id":399897098,"identity":"a9ff9c19-133e-48e0-80bf-1b80a224a326","order_by":4,"name":"Yupeng Lu","email":"","orcid":"","institution":"Chengdu University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Yupeng","middleName":"","lastName":"Lu","suffix":""},{"id":399897099,"identity":"b4cdd1eb-b4da-40ca-a838-ffa3cd4e8215","order_by":5,"name":"Hao Man","email":"","orcid":"","institution":"Chengdu University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Hao","middleName":"","lastName":"Man","suffix":""},{"id":399897100,"identity":"4fbe82d4-e8c6-4156-80f7-86615074d123","order_by":6,"name":"Jingyong Wang","email":"","orcid":"","institution":"Chengdu University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Jingyong","middleName":"","lastName":"Wang","suffix":""},{"id":399897101,"identity":"b6c26b4a-047c-4993-9057-af15ba1e88c6","order_by":7,"name":"Feng Ji","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzklEQVRIiWNgGAWjYBACxmbGBxDWAQbGBwkVNcRoYTaAamFmNnhw5hgx9iC0sEk+bGEmQkM7M+Pjgl8M8nw38o9VJDawMfC3dycQchiz8cw+BsOZN5LZbiTukGGQOHN2AwEt/MekeXsYEgzAWs6wMRhI5BLSwsz+G6alILGNmSgtbMw8PyBaGIjVwizN2wD0y5nHxhIJZ47xEPSLYf9hxs88f4Ahdjzx4ccfFTVy/O29BLQ0gKxq+w8X4MGrHATkweQfgupGwSgYBaNgJAMAHA5FMwg0ovoAAAAASUVORK5CYII=","orcid":"","institution":"Chengdu University of Technology","correspondingAuthor":true,"prefix":"","firstName":"Feng","middleName":"","lastName":"Ji","suffix":""}],"badges":[],"createdAt":"2025-01-08 08:23:19","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5787047/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5787047/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":74612993,"identity":"fe73b89a-2c18-4ac4-966a-ae758989d179","added_by":"auto","created_at":"2025-01-24 03:46:41","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":755417,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5787047/v1_covered_dd4bbcfd-4a45-4d69-a798-ffe456f5e72e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A New Classification Method of Surrounding Rock Quality for Phyllite Tunnels under the Condition of Layer Orientation Parallel to the orientation of tunnel Axis","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Surrounding rock quality classification, HC method, Anisotropy characteristic, Phyllite tunnel","lastPublishedDoi":"10.21203/rs.3.rs-5787047/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5787047/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSurrounding rock classification is a critical factor in evaluating tunnel stability, determining construction methods, and selecting support parameters. Various engineering sectors utilize different methods for grading tunnel surrounding rock quality. The HC method iswidely adopted in the hydropower industry for this purpose. However, due to the anisotropy of layered phyllite, the classification results obtained using the HC method for phyllite tunnels\u0026mdash;when the layer orientation is parallel to the tunnel axis-differ significantly from those based on actual field investigations. This study conducted uniaxial compression tests on rocks, revealing that layered phyllite exhibits notable anisotropy at bedding angles of 0\u0026deg;, 45\u0026deg;, and 90\u0026deg;. The compressive strength follows a V-shaped trend as the angle between the bedding and loading orientations changes, while the deformation modulus decreases linearly with increasing angular deviation between the loading orientation and tunnel axis. Numerical simulations were performed to observe tunnel deformation at various bedding-to-tunnel axis angles. Results showed that, as the bedding angle decreases, deformation of the tunnel wall and crown increases progressively. At angles of 0\u0026deg;, 30\u0026deg;, 45\u0026deg;, 60\u0026deg;, and 90\u0026deg;, the deformation ratios for the tunnel wall were 1:3.7:3:4.74:5.44:7.7, and for the tunnel crown, the ratios were 1:1.3:1.94:4.7:6.7. When the traditional HC method was used to classify the surrounding rock in tunnels with parallel phyllite layers, the agreement rate was only 13.33%, indicating low accuracy. By modifying the occurrence score for major structural joints and incorporating the weight ratios derived from numerical simulations, the HC method\u0026rsquo;s accuracy improved, achieving an agreement rate of 100%. This study enhances the precision and applicability of surrounding rock classification and offers valuable insights for tunnel construction.\u003c/p\u003e","manuscriptTitle":"A New Classification Method of Surrounding Rock Quality for Phyllite Tunnels under the Condition of Layer Orientation Parallel to the orientation of tunnel Axis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-01-13 16:39:32","doi":"10.21203/rs.3.rs-5787047/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f82079c9-26ab-42df-87b5-83214b7b0557","owner":[],"postedDate":"January 13th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-01-24T03:38:32+00:00","versionOfRecord":[],"versionCreatedAt":"2025-01-13 16:39:32","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5787047","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5787047","identity":"rs-5787047","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}