A combined nanoindentation and numerical modeling investigation on the apparent mechanical properties of constituent minerals in soft rock

A combined nanoindentation and numerical modeling investigation on the apparent mechanical properties of constituent minerals in soft rock | 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 A combined nanoindentation and numerical modeling investigation on the apparent mechanical properties of constituent minerals in soft rock Changlun Sun, Jiahui Xu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9210888/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 Although nanoindentation has been widely employed to measure the mesoscopic mechanical properties of rock-forming mineral particles, a critical gap exists in understanding how the mechanical response of a given mineral varies across different soft rocks. Here, nanoindentation tests were conducted to measure the mechanical properties, such as hardness, elastic modulus, and plastic energy ratio, of quartz and kaolinite minerals in both sandstone and mudstone. Mesoscopic observations show that quartz particles constitute the skeleton of the sandstone, and clay minerals, i.e., kaolinite, present as filling materials in the pores between the quartz skeleton; in mudstone, however, quartz particles are scattered in the matrix of clay matrix. The nanoindentation measured apparent values of hardness and elastic modulus of quartz are 8.24% and 11.75% higher, respectively, in sandstone than in mudstone. For kaolinite, these differences are even more pronounced, with hardness and elastic modulus values being 51.28% and 70.06% greater in sandstone. The plastic energy ratio of quartz is lower in sandstone, while that of kaolinite is higher. The surrounding constraint effect is numerically investigated to explain the variability in measured properties of the same constituent mineral across different soft rocks. The quartz is surrounded by mudstone clay matrix decreases its apparent hardness and elastic modulus and increases its plastic energy ratio compared to when it is in a quartz-rich sandstone framework. The kaolinite is confined by a rigid quartz skeleton in sandstone increases its measured properties compared to when it forms the unconfined, bulk clay matrix in mudstone. It is recommended that the ratio of indentation depth to mineral particle diameter be maintained below 0.1 to measure the absolute mechanical properties. Physical sciences/Materials science Earth and environmental sciences/Solid earth sciences Nanoindentation soft rock constituent mineral mechanical property Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 12 May, 2026 Reviewers agreed at journal 17 Apr, 2026 Reviewers invited by journal 10 Apr, 2026 Editor assigned by journal 07 Apr, 2026 Submission checks completed at journal 27 Mar, 2026 First submitted to journal 27 Mar, 2026 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-9210888","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":620824641,"identity":"52c02c8d-f229-43bd-b8d0-dd81195730a6","order_by":0,"name":"Changlun Sun","email":"","orcid":"","institution":"Guizhou Institute of Technology","correspondingAuthor":false,"prefix":"","firstName":"Changlun","middleName":"","lastName":"Sun","suffix":""},{"id":620824642,"identity":"190ad587-bdf8-4447-a537-a6334b4fdbb7","order_by":1,"name":"Jiahui Xu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAxklEQVRIiWNgGAWjYBAC+xs87D8SKmygXDYitLBJ8DBIfDiTBmQyk6BFcmbbYVK0SPceMOZhOy9vcO38AYYPZYcZ+Gc3ENAicy4hmYfntuGG28kMjDPOHWaQuHOAkMNyDA7zSNxOMABqYeYFutBAIoGgFsNmHoNzEC1/idRizDgj4QBECyNRWmTOmDF8OJBsOPN2ssHBnnPpPBI3CGmR7jFjSPxnJ893O/Hhgx9l1nL8MwhoQQEHgJiHBPWjYBSMglEwCnABACt7PyDK78CcAAAAAElFTkSuQmCC","orcid":"","institution":"China University of Mining and Technology","correspondingAuthor":true,"prefix":"","firstName":"Jiahui","middleName":"","lastName":"Xu","suffix":""}],"badges":[],"createdAt":"2026-03-24 10:55:57","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9210888/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9210888/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":107183901,"identity":"8007a51b-6c76-476c-9017-8c1af80b6016","added_by":"auto","created_at":"2026-04-17 18:20:45","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1766954,"visible":true,"origin":"","legend":"","description":"","filename":"Sunetal.Manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9210888/v1_covered_502fe72d-2fd8-4c15-b09c-49e594d0d314.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A combined nanoindentation and numerical modeling investigation on the apparent mechanical properties of constituent minerals in soft rock","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"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":"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":"Nanoindentation, soft rock, constituent mineral, mechanical property","lastPublishedDoi":"10.21203/rs.3.rs-9210888/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9210888/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eAlthough nanoindentation has been widely employed to measure the mesoscopic mechanical properties of rock-forming mineral particles, a critical gap exists in understanding how the mechanical response of a given mineral varies across different soft rocks. Here, nanoindentation tests were conducted to measure the mechanical properties, such as hardness, elastic modulus, and plastic energy ratio, of quartz and kaolinite minerals in both sandstone and mudstone. Mesoscopic observations show that quartz particles constitute the skeleton of the sandstone, and clay minerals, i.e., kaolinite, present as filling materials in the pores between the quartz skeleton; in mudstone, however, quartz particles are scattered in the matrix of clay matrix. The nanoindentation measured apparent values of hardness and elastic modulus of quartz are 8.24% and 11.75% higher, respectively, in sandstone than in mudstone. For kaolinite, these differences are even more pronounced, with hardness and elastic modulus values being 51.28% and 70.06% greater in sandstone. The plastic energy ratio of quartz is lower in sandstone, while that of kaolinite is higher. The surrounding constraint effect is numerically investigated to explain the variability in measured properties of the same constituent mineral across different soft rocks. The quartz is surrounded by mudstone clay matrix decreases its apparent hardness and elastic modulus and increases its plastic energy ratio compared to when it is in a quartz-rich sandstone framework. The kaolinite is confined by a rigid quartz skeleton in sandstone increases its measured properties compared to when it forms the unconfined, bulk clay matrix in mudstone. It is recommended that the ratio of indentation depth to mineral particle diameter be maintained below 0.1 to measure the absolute mechanical properties.\u003c/p\u003e","manuscriptTitle":"A combined nanoindentation and numerical modeling investigation on the apparent mechanical properties of constituent minerals in soft rock","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-17 18:20:23","doi":"10.21203/rs.3.rs-9210888/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-05-13T02:14:32+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"178972942121541044951063123940881104305","date":"2026-04-17T17:00:21+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-10T08:49:13+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-07T08:01:17+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-27T07:46:23+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2026-03-27T07:31:22+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":"c6fd84bc-75db-4a04-826e-96d76439f37d","owner":[],"postedDate":"April 17th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"","date":"2026-05-13T02:14:32+00:00","index":15,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":66069618,"name":"Physical sciences/Materials science"},{"id":66069619,"name":"Earth and environmental sciences/Solid earth sciences"}],"tags":[],"updatedAt":"2026-04-17T18:20:24+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-17 18:20:23","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9210888","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9210888","identity":"rs-9210888","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}