Experimental Study on the Reinforcement Performance of Unloading-Damaged Mudstone by Microbial Grouting

Experimental Study on the Reinforcement Performance of Unloading-Damaged Mudstone by Microbial Grouting | 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 Experimental Study on the Reinforcement Performance of Unloading-Damaged Mudstone by Microbial Grouting Yan Guo, Huafeng Deng, Yongqi Chen, Wenxi Zhu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9278323/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 To address the structural deterioration and water-induced swelling of mudstone caused by unloading damage during foundation excavation, grouting reinforcement tests using MICP and volcanic ash-assisted MICP were conducted. Mudstone specimens with unloading damage degrees of 70%-90% were prepared through triaxial unloading tests. Combined with lateral constrained swelling tests, triaxial compression tests, and SEM analysis, the swelling deformation, mechanical properties, and micro-mechanisms of unloading-damaged mudstone under different reinforcement methods were systematically investigated. The results show that unloading damage significantly weakens the strength of mudstone and enhances its swelling sensitivity. Both MICP and volcanic ash-assisted MICP can effectively inhibit swelling deformation and improve strength. Specifically, MICP increased the residual strength by 7.41%-13.98% and the peak strength by 2.49%-6.34%, while volcanic ash-assisted MICP increased them by 13.45%-20.61% and 5.36%-9.45%, respectively. SEM results show that the mineralization products improve the structural integrity of mudstone by filling pores, sealing cracks, and enhancing interparticle cementation. The incorporation of volcanic ash further promotes mineral precipitation and the formation of a composite cementation structure, resulting in a better reinforcement effect than that of conventional MICP. Unloading damage Mudstone MICP Mechanical properties Volcanic ash 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-9278323","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":615619596,"identity":"4fc45af4-fa8d-475b-94f1-a66ba62f777f","order_by":0,"name":"Yan Guo","email":"","orcid":"","institution":"Power China Hubei Electric Engineering Co., Ltd.","correspondingAuthor":false,"prefix":"","firstName":"Yan","middleName":"","lastName":"Guo","suffix":""},{"id":615619598,"identity":"0f8105bd-0f1d-42dd-b20b-a5792c3bbe6d","order_by":1,"name":"Huafeng Deng","email":"","orcid":"","institution":"College of Civil Engineering \u0026 Architecture, China Three Gorges University","correspondingAuthor":false,"prefix":"","firstName":"Huafeng","middleName":"","lastName":"Deng","suffix":""},{"id":615619601,"identity":"cf499a87-e11d-4649-9756-81e80b9bdd15","order_by":2,"name":"Yongqi Chen","email":"","orcid":"","institution":"Power China Jiangxi Hydropower Engineering Bureau Co., Ltd","correspondingAuthor":false,"prefix":"","firstName":"Yongqi","middleName":"","lastName":"Chen","suffix":""},{"id":615619603,"identity":"db8a78b9-70ad-40cb-8ef9-9b35ae4697a7","order_by":3,"name":"Wenxi Zhu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyUlEQVRIiWNgGAWjYHACxgcfKqBMHiK1MBvOOMMgQZIWNmneNlK0yM/IMZOcOc+uTj4igfHB2zYGeXNCWhhnpCVbfNyWLGF4I4HZcG4bg+HOBgJamKWTD96cue2AhOGMBLALEwwOEPRIYoM07xywFvbfRGnhkU4+JM3bcEBCXiKBjZkoLRLyz5INZxxLltzA87BZcs45CcMNhLTI95wxfPChxo5fvj354Ic3ZTbyBG2BA4MDjA0gW4lVD7KugQTFo2AUjIJRMLIAAL0GO9cpsSw/AAAAAElFTkSuQmCC","orcid":"","institution":"College of Civil Engineering \u0026 Architecture, China Three Gorges University","correspondingAuthor":true,"prefix":"","firstName":"Wenxi","middleName":"","lastName":"Zhu","suffix":""}],"badges":[],"createdAt":"2026-03-31 10:23:51","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9278323/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9278323/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106993588,"identity":"5e15ddf3-9703-4d92-84ca-93ca42f3282b","added_by":"auto","created_at":"2026-04-15 14:38:40","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":761682,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9278323/v1_covered_4f9df7ac-9381-4dba-91cf-19b833b64312.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Experimental Study on the Reinforcement Performance of Unloading-Damaged Mudstone by Microbial Grouting","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":"Unloading damage, Mudstone, MICP, Mechanical properties, Volcanic ash","lastPublishedDoi":"10.21203/rs.3.rs-9278323/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9278323/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eTo address the structural deterioration and water-induced swelling of mudstone caused by unloading damage during foundation excavation, grouting reinforcement tests using MICP and volcanic ash-assisted MICP were conducted. Mudstone specimens with unloading damage degrees of 70%-90% were prepared through triaxial unloading tests. Combined with lateral constrained swelling tests, triaxial compression tests, and SEM analysis, the swelling deformation, mechanical properties, and micro-mechanisms of unloading-damaged mudstone under different reinforcement methods were systematically investigated. The results show that unloading damage significantly weakens the strength of mudstone and enhances its swelling sensitivity. Both MICP and volcanic ash-assisted MICP can effectively inhibit swelling deformation and improve strength. Specifically, MICP increased the residual strength by 7.41%-13.98% and the peak strength by 2.49%-6.34%, while volcanic ash-assisted MICP increased them by 13.45%-20.61% and 5.36%-9.45%, respectively. SEM results show that the mineralization products improve the structural integrity of mudstone by filling pores, sealing cracks, and enhancing interparticle cementation. The incorporation of volcanic ash further promotes mineral precipitation and the formation of a composite cementation structure, resulting in a better reinforcement effect than that of conventional MICP.\u003c/p\u003e","manuscriptTitle":"Experimental Study on the Reinforcement Performance of Unloading-Damaged Mudstone by Microbial Grouting","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-06 16:48:37","doi":"10.21203/rs.3.rs-9278323/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":"2466a7e6-22b4-4769-a283-1574cb9e59ec","owner":[],"postedDate":"April 6th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-11T03:54:24+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-06 16:48:37","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9278323","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9278323","identity":"rs-9278323","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}