Degradation of small-strain shear modulus of expansive soils under repeated wetting–drying cycles: Experimental evidence and damage- based modeling

Degradation of small-strain shear modulus of expansive soils under repeated wetting–drying cycles: Experimental evidence and damage- based modeling | 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 Degradation of small-strain shear modulus of expansive soils under repeated wetting–drying cycles: Experimental evidence and damage- based modeling Xiaotong Qin, Yangcong Li, Shanhao Li, Dongjie Zhang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9338464/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract The study of the small-strain stiffness of soil is important for analyzing the deformation of ground and geotechnical structures. Nevertheless, the damage behavior and the predicted model of the small-strain shear modulus G max for expansive soils subjected to multiple wetting–drying cycles have rarely been investigated. In this study, bender element tests were conducted on unsaturated expansive soils with different initial void ratios subjected to repeated wetting–drying cycles to elucidate the degradation behavior of the small-strain shear modulus. Subsequently, a new damage-based small-strain shear modulus prediction model for expansive soils was proposed and validated. The experimental findings demonstrate significant degradation in G max of expansive soils under wetting–drying cycles, primarily following the first cycle. More importantly, a unified dependence of G max on the evolution of matric suction is established across different cycles. X-ray CT analyses reveal the underlying microstructural shift from a particle-dominated fabric to a crack-connected network. Based on this, a damage-based model is proposed that links G max degradation directly to the air–entry value evolution of the soil–water characteristic curve. The model is validated with a prediction determination coefficient exceeding 0.90. Its key strength lies in the ability to predict G max without requiring prior knowledge of the number of wetting–drying cycles, providing a practical and reliable tool for engineering assessments under uncertain cyclic histories. Physical sciences/Engineering Physical sciences/Materials science Earth and environmental sciences/Solid earth sciences small-strain stiffness expansive soil wetting–drying cycles damage model of small-strain shear modulus Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 28 Apr, 2026 Reviews received at journal 27 Apr, 2026 Reviewers agreed at journal 18 Apr, 2026 Reviews received at journal 18 Apr, 2026 Reviewers agreed at journal 18 Apr, 2026 Reviewers invited by journal 16 Apr, 2026 Editor assigned by journal 16 Apr, 2026 Editor invited by journal 16 Apr, 2026 Submission checks completed at journal 13 Apr, 2026 First submitted to journal 13 Apr, 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. 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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-9338464","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":625592021,"identity":"2d572b4f-bf93-4b9f-ad50-81fca0f58f6b","order_by":0,"name":"Xiaotong Qin","email":"","orcid":"","institution":"Southwest Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Xiaotong","middleName":"","lastName":"Qin","suffix":""},{"id":625592023,"identity":"fa37ac56-a19a-4766-8d36-9422022645af","order_by":1,"name":"Yangcong Li","email":"","orcid":"","institution":"Southwest Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Yangcong","middleName":"","lastName":"Li","suffix":""},{"id":625592024,"identity":"ec5ea771-3ad5-4be3-ae30-cbcaac2b0791","order_by":2,"name":"Shanhao Li","email":"","orcid":"","institution":"Southwest Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Shanhao","middleName":"","lastName":"Li","suffix":""},{"id":625592026,"identity":"7a134b7c-eec8-4cea-b987-d59f7edae9fb","order_by":3,"name":"Dongjie Zhang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAw0lEQVRIiWNgGAWjYDCCAwcYDnwwYJNjY28/QLQWxoczCviM+XjOJBCrhYHZmOeDXOI8CQcD4nTwHTz+THKGgVl6mwRDAsOPim2EtUgeOJAm8cEgLbdNuvEAY8+Z24S1GBw4cAxoy7HcNpkDCcyMbURpOdgmzWPwP51NIsGAWC2Hgd43YEsgXovkgWPAQDZgM2wDBvJBovzCd+P4gwMf/rDJy7e3H3zwo4IILQwSBxDsA7gUoQL+BuLUjYJRMApGwQgGAG1cQ8UfFQuYAAAAAElFTkSuQmCC","orcid":"","institution":"Xichang University","correspondingAuthor":true,"prefix":"","firstName":"Dongjie","middleName":"","lastName":"Zhang","suffix":""}],"badges":[],"createdAt":"2026-04-07 02:38:46","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9338464/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9338464/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":107687641,"identity":"be095e85-099b-4bdc-aa4f-c3ce5c46be64","added_by":"auto","created_at":"2026-04-24 04:55:19","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1439143,"visible":true,"origin":"","legend":"","description":"","filename":"RevisedManuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9338464/v1_covered_fdf710b5-eab1-4445-b637-f54e41336461.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Degradation of small-strain shear modulus of expansive soils under repeated wetting–drying cycles: Experimental evidence and damage- based modeling","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":"small-strain stiffness, expansive soil, wetting–drying cycles, damage model of small-strain shear modulus","lastPublishedDoi":"10.21203/rs.3.rs-9338464/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9338464/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe study of the small-strain stiffness of soil is important for analyzing the deformation of ground and geotechnical structures. Nevertheless, the damage behavior and the predicted model of the small-strain shear modulus \u003cem\u003eG\u003c/em\u003e\u003csub\u003emax\u003c/sub\u003e for expansive soils subjected to multiple wetting\u0026ndash;drying cycles have rarely been investigated. In this study, bender element tests were conducted on unsaturated expansive soils with different initial void ratios subjected to repeated wetting\u0026ndash;drying cycles to elucidate the degradation behavior of the small-strain shear modulus. Subsequently, a new damage-based small-strain shear modulus prediction model for expansive soils was proposed and validated. The experimental findings demonstrate significant degradation in \u003cem\u003eG\u003c/em\u003e\u003csub\u003emax\u003c/sub\u003e of expansive soils under wetting\u0026ndash;drying cycles, primarily following the first cycle. 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