Impact of silt content on the compression and settlement behavior of gravel cushions in immersed tunnel foundation

Impact of silt content on the compression and settlement behavior of gravel cushions in immersed tunnel foundation | 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 Impact of silt content on the compression and settlement behavior of gravel cushions in immersed tunnel foundation Wu Qixian, Fu Baiyong, Lu Xingbang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6650369/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 Siltation in the cushion layer is a critical issue influencing the foundation construction and the sinking of pipe sections in immersed tunnels. This study investigates the impact of silt content on the mechanical behavior of gravel cushions used in the Shenzhong Link immersed tunnel, combining laboratory confined compression tests and PFC3D numerical simulations. The macroscopic effects of varying silt proportions on displacement and settlement are analyzed, alongside the underlying microscopic mechanisms related to porosity, contact strength, and the formation of strong contact force chains. Results show that increased silt content leads to a reduction in both the void ratio and the contact elastic modulus of the gravel cushion, with a 10% increase in silt content causing a 13%-21% reduction in modulus. Additionally, higher silt content weakens the frictional and interlocking properties between particles, resulting in a significant increase in the number of strong contact force chains under high-stress conditions. This change facilitates more pronounced particle space recombination, further influencing the deformation characteristics of the gravel cushion layer. Physical sciences/Engineering/Civil engineering Physical sciences/Engineering/Mechanical engineering Siltation Immersed tunnel Gravel cushion Compression test Particle flow simulation Full Text Additional Declarations No competing interests reported. Supplementary Files Supplementarymaterial.zip 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. 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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-6650369","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":468043062,"identity":"8f8674c4-a9f7-4808-a563-d1d46c5dc2d2","order_by":0,"name":"Wu Qixian","email":"","orcid":"","institution":"Shunde District Engineering Construction Center","correspondingAuthor":false,"prefix":"","firstName":"Wu","middleName":"","lastName":"Qixian","suffix":""},{"id":468043063,"identity":"28501d39-f6ad-4ed0-a162-dcaf548300dc","order_by":1,"name":"Fu Baiyong","email":"","orcid":"","institution":"CCCC Highway Long Bridge Construction National Engineering Research Center Co., Ltd","correspondingAuthor":false,"prefix":"","firstName":"Fu","middleName":"","lastName":"Baiyong","suffix":""},{"id":468043064,"identity":"c3b79fda-5395-46ed-b3c9-655e1d165ccb","order_by":2,"name":"Lu Xingbang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAs0lEQVRIiWNgGAWjYDACZgY2BoYCBjk29vYDpGgxYDDm4zmTQLQ9YC2J8yQcDIhTL9/Onfbgh8Hh9DYJhgSGHxXbCGsxOMy73bDH4HBum3TjAcaeM7eJ0MLMu02CB6RF5kACM2MbEVrkm3m3Sf4BOoxNIsGAOC0Mh3m3SQNtSSBeC8gvxjIG6YZtwEA+SJRf5PvPbnv4psJaXr69/eCDHxXEOAwZHCBR/SgYBaNgFIwCXAAA0Bc3do0+wTwAAAAASUVORK5CYII=","orcid":"","institution":"CCCC Highway Long Bridge Construction National Engineering Research Center Co., Ltd","correspondingAuthor":true,"prefix":"","firstName":"Lu","middleName":"","lastName":"Xingbang","suffix":""}],"badges":[],"createdAt":"2025-05-13 01:53:19","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6650369/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6650369/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":85043741,"identity":"612aa5e9-75c1-4135-a7f3-9b06c9d242aa","added_by":"auto","created_at":"2025-06-20 09:53:40","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":728876,"visible":true,"origin":"","legend":"","description":"","filename":"Impactofsiltcontentonthecompressionandsettlementbehaviorofgravelcushionsinimmersedtunnelfoundation.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6650369/v1_covered_a4d6d4b4-6b27-4ba3-934e-f44f371d56cc.pdf"},{"id":84207696,"identity":"7a15170b-a5ac-4817-881e-d41f6e27f800","added_by":"auto","created_at":"2025-06-09 09:28:17","extension":"zip","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":28120342,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementarymaterial.zip","url":"https://assets-eu.researchsquare.com/files/rs-6650369/v1/bbdca8cadc4d1df2487f1b8b.zip"}],"financialInterests":"No competing interests reported.","formattedTitle":"Impact of silt content on the compression and settlement behavior of gravel cushions in immersed tunnel foundation","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":"Siltation, Immersed tunnel, Gravel cushion, Compression test, Particle flow simulation","lastPublishedDoi":"10.21203/rs.3.rs-6650369/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6650369/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSiltation in the cushion layer is a critical issue influencing the foundation construction and the sinking of pipe sections in immersed tunnels. This study investigates the impact of silt content on the mechanical behavior of gravel cushions used in the Shenzhong Link immersed tunnel, combining laboratory confined compression tests and PFC3D numerical simulations. The macroscopic effects of varying silt proportions on displacement and settlement are analyzed, alongside the underlying microscopic mechanisms related to porosity, contact strength, and the formation of strong contact force chains. Results show that increased silt content leads to a reduction in both the void ratio and the contact elastic modulus of the gravel cushion, with a 10% increase in silt content causing a 13%-21% reduction in modulus. Additionally, higher silt content weakens the frictional and interlocking properties between particles, resulting in a significant increase in the number of strong contact force chains under high-stress conditions. 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