Time-dependent strength growth of paste backfill: Insights into optimization of key parameters for longwall backfilling mining

Time-dependent strength growth of paste backfill: Insights into optimization of key parameters for longwall backfilling mining | 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 Time-dependent strength growth of paste backfill: Insights into optimization of key parameters for longwall backfilling mining yu zhang, Guangyuan Song, Yidong Zhang, Zexin Li, Shaobo Sun, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8876520/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 A time-dependent modeling approach accounting for the sequential strength increase of backfill is proposed for optimizing key parameters in longwall paste backfilling. Based on the E1302-B face in the Gaohe Coal Mine, a systematic study involving laboratory strength tests, numerical simulations, and in‑site industrial tests was conducted to quantitatively reveal the coupled influence of backfill strength evolution on critical parameters, including backfilling step distance, final cured strength, and backfilling ratio. The results show that the strength of paste backfill grows as a logarithmic function over time. A backfilling step distance of 2.4 m achieves the best balance between mining efficiency and control effectiveness while ensuring roof stability and surface protection. The final cured strength shows a clear marginal effect: increasing from 3.21 MPa to 4.01 MPa improves control significantly, whereas a further rise to 5.03 MPa yields sharply diminishing returns; 4.01 MPa is thus recommended. A backfilling ratio no lower than 92% is required to meet the Grade‑I surface protection standard. Field trials confirmed the rationality of the proposed parameters: under a 2.4 m backfilling step, the roof exhibited continuous bending subsidence without fracturing; the minimum backfilling ratio exceeded 92%, the average Final Cured Strength of the backfill reached 4.4 MPa, the maximum surface subsidence was 215 mm, and the maximum horizontal deformation was 0.7 mm/m. All deformation indices remained below 50% of the regulatory limits, effectively ensuring the safety of surface structures. This study provides a theoretical foundation and engineering guidance for the refined design and optimization of key parameters in longwall paste backfilling mining. longwall paste backfilling time dependent strength backfilling step distance final cured strength backfilling ratio surface subsidence control 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-8876520","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":591797700,"identity":"2495b614-4b5d-45b4-be11-6a72e2708c6d","order_by":0,"name":"yu zhang","email":"","orcid":"","institution":"China University of Mining and Technology","correspondingAuthor":false,"prefix":"","firstName":"yu","middleName":"","lastName":"zhang","suffix":""},{"id":591797704,"identity":"292966f6-4609-44a6-b89a-01c4125ae5ce","order_by":1,"name":"Guangyuan 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strength, backfilling ratio, surface subsidence control","lastPublishedDoi":"10.21203/rs.3.rs-8876520/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8876520/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eA time-dependent modeling approach accounting for the sequential strength increase of backfill is proposed for optimizing key parameters in longwall paste backfilling. Based on the E1302-B face in the Gaohe Coal Mine, a systematic study involving laboratory strength tests, numerical simulations, and in‑site industrial tests was conducted to quantitatively reveal the coupled influence of backfill strength evolution on critical parameters, including backfilling step distance, final cured strength, and backfilling ratio. The results show that the strength of paste backfill grows as a logarithmic function over time. A backfilling step distance of 2.4 m achieves the best balance between mining efficiency and control effectiveness while ensuring roof stability and surface protection. The final cured strength shows a clear marginal effect: increasing from 3.21 MPa to 4.01 MPa improves control significantly, whereas a further rise to 5.03 MPa yields sharply diminishing returns; 4.01 MPa is thus recommended. A backfilling ratio no lower than 92% is required to meet the Grade‑I surface protection standard. Field trials confirmed the rationality of the proposed parameters: under a 2.4 m backfilling step, the roof exhibited continuous bending subsidence without fracturing; the minimum backfilling ratio exceeded 92%, the average Final Cured Strength of the backfill reached 4.4 MPa, the maximum surface subsidence was 215 mm, and the maximum horizontal deformation was 0.7 mm/m. All deformation indices remained below 50% of the regulatory limits, effectively ensuring the safety of surface structures. This study provides a theoretical foundation and engineering guidance for the refined design and optimization of key parameters in longwall paste backfilling mining.\u003c/p\u003e","manuscriptTitle":"Time-dependent strength growth of paste backfill: Insights into optimization of key parameters for longwall backfilling mining","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-20 14:29:14","doi":"10.21203/rs.3.rs-8876520/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":"1f3324c9-dce8-4604-9627-2663ffa5c3dd","owner":[],"postedDate":"February 20th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-05T07:11:23+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-20 14:29:14","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8876520","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8876520","identity":"rs-8876520","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}