Influence of confining pressure and stress amplitude on mechanical properties and permeability characteristics of coal

Influence of confining pressure and stress amplitude on mechanical properties and permeability characteristics of coal | 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 Article Influence of confining pressure and stress amplitude on mechanical properties and permeability characteristics of coal Huiming Yang, Dengke Qin, Hao Liu, Xiaoyan Sun, Qican Ran, Yulin Hu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7873691/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 23 Jan, 2026 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract In order to explore the influence mechanism of confining pressure and stress amplitude on the mechanical properties and permeability characteristics of coal samples, the loading and unloading experiments of different confining pressures and amplitudes were carried out by triaxial test system. The stress-strain, permeability and energy changes of coal samples were monitored in real time, and the stress response, energy evolution, creep deformation and fracture distribution characteristics were systematically analyzed. The experimental results show that with the increase of confining pressure, the peak stress and elastic modulus of coal samples increase significantly, the input energy and elastic energy increase synchronously, and the permeability and fracture ratio decrease significantly. The high confining pressure effectively inhibits the fracture expansion, makes the structure of the coal sample more regular after the destruction, the fractal dimension decreases as a whole, and the structure tends to be simplified and densified. On the contrary, the increase of loading and unloading amplitude will aggravate the structural failure and fatigue damage process of coal samples, resulting in the decrease of peak strength, the increase of irreversible strain, the expansion and penetration of cracks, the increase of fracture proportion and fractal dimension, and the significant increase of permeability. The results of three-dimensional fracture reconstruction further confirm the significant influence of confining pressure and amplitude on the evolution of fracture spatial structure. The increase of confining pressure helps to close micro-cracks and compact pore channels, while the large amplitude disturbance promotes fracture penetration and forms a flow network. Physical sciences/Energy science and technology Physical sciences/Engineering Physical sciences/Materials science Earth and environmental sciences/Solid earth sciences confining pressure amplitude mechanical properties permeability characteristics Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 23 Jan, 2026 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 02 Dec, 2025 Reviews received at journal 22 Nov, 2025 Reviews received at journal 13 Nov, 2025 Reviewers agreed at journal 09 Nov, 2025 Reviewers agreed at journal 03 Nov, 2025 Reviewers invited by journal 03 Nov, 2025 Editor assigned by journal 27 Oct, 2025 Editor invited by journal 27 Oct, 2025 Submission checks completed at journal 19 Oct, 2025 First submitted to journal 19 Oct, 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. 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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-7873691","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":542325084,"identity":"4d5be265-d632-4df2-92bd-e4529300fa0d","order_by":0,"name":"Huiming Yang","email":"","orcid":"","institution":"State Key Laboratory of Gas Disaster Detecting, Preventing and Emergency Controlling","correspondingAuthor":false,"prefix":"","firstName":"Huiming","middleName":"","lastName":"Yang","suffix":""},{"id":542325086,"identity":"8ee7cc89-8228-496e-b479-444447edd244","order_by":1,"name":"Dengke 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coal","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"confining pressure, amplitude, mechanical properties, permeability characteristics","lastPublishedDoi":"10.21203/rs.3.rs-7873691/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7873691/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn order to explore the influence mechanism of confining pressure and stress amplitude on the mechanical properties and permeability characteristics of coal samples, the loading and unloading experiments of different confining pressures and amplitudes were carried out by triaxial test system. The stress-strain, permeability and energy changes of coal samples were monitored in real time, and the stress response, energy evolution, creep deformation and fracture distribution characteristics were systematically analyzed. The experimental results show that with the increase of confining pressure, the peak stress and elastic modulus of coal samples increase significantly, the input energy and elastic energy increase synchronously, and the permeability and fracture ratio decrease significantly. The high confining pressure effectively inhibits the fracture expansion, makes the structure of the coal sample more regular after the destruction, the fractal dimension decreases as a whole, and the structure tends to be simplified and densified. On the contrary, the increase of loading and unloading amplitude will aggravate the structural failure and fatigue damage process of coal samples, resulting in the decrease of peak strength, the increase of irreversible strain, the expansion and penetration of cracks, the increase of fracture proportion and fractal dimension, and the significant increase of permeability. The results of three-dimensional fracture reconstruction further confirm the significant influence of confining pressure and amplitude on the evolution of fracture spatial structure. The increase of confining pressure helps to close micro-cracks and compact pore channels, while the large amplitude disturbance promotes fracture penetration and forms a flow network.\u003c/p\u003e","manuscriptTitle":"Influence of confining pressure and stress amplitude on mechanical properties and permeability characteristics of coal","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-13 19:15:58","doi":"10.21203/rs.3.rs-7873691/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-02T13:04:28+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-22T12:19:52+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-14T02:23:59+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"30006835043914143667074329482654290648","date":"2025-11-10T01:14:08+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"191463908121787941287522258637147462839","date":"2025-11-04T03:28:32+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-04T03:06:38+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-27T07:20:56+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-10-27T07:16:11+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-10-19T11:29:26+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-10-19T11:26:23+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"28d359d7-015e-436b-b466-f16b89588832","owner":[],"postedDate":"November 13th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":57689073,"name":"Physical sciences/Energy science and technology"},{"id":57689074,"name":"Physical sciences/Engineering"},{"id":57689075,"name":"Physical sciences/Materials science"},{"id":57689076,"name":"Earth and environmental sciences/Solid earth sciences"}],"tags":[],"updatedAt":"2026-01-26T16:00:15+00:00","versionOfRecord":{"articleIdentity":"rs-7873691","link":"https://doi.org/10.1038/s41598-026-35979-4","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2026-01-23 15:57:27","publishedOnDateReadable":"January 23rd, 2026"},"versionCreatedAt":"2025-11-13 19:15:58","video":"","vorDoi":"10.1038/s41598-026-35979-4","vorDoiUrl":"https://doi.org/10.1038/s41598-026-35979-4","workflowStages":[]},"version":"v1","identity":"rs-7873691","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7873691","identity":"rs-7873691","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}