{"title":"Injection Micropile Bar Fatigue Resistance at Loads Lower and Greater than the Yield Strength of Steel","authors":"A. Pytlik, W. Frąc","doi":"10.24425/ams.2024.150339","DOIUrl":null,"url":null,"abstract":"One of the techniques commonly applied today for deep foundation construction is based on self-drilling injection micropiles. Micropiles are structural elements intended primarily for reinforcing foundations and buildings, particularly under difficult terrain conditions. The goal of the tests presented herein is to inspect the fatigue resistance, strength and ductility of injection micropiles formed from 28Mn6 steel at loads significantly exceeding the values defined for the fatigue test in the requirements of the relevant European Assessment Document (EAD). The test results and the micropile bar strain model εM presented in this paper are primarily of interest to designers for the purposes of determining the fatigue resistance of steel micropiles, which find particular application in land degraded by mining activity that is characterised by frequent terrain vibration and mining-induced tremors. None of the R25N injection micropile bars failed during the fatigue resistance testing at 2·106 cycles at a load Fu = 0.7·FRe0.2 (under the yield strength of the 28Mn6 steel) as well as at Fu = 1.0·FRe0.2 and Fu = 1.2·FRe0.2, where the bars operated at the limit of and significantly above the load FRe0.2 which results in stress at the yield point of the 28Mn6 steel. Furthermore, the bar tests conducted at static and cyclic loading demonstrated the high strength and good ductility of the 28Mn6 steel.","PeriodicalId":55468,"journal":{"name":"Archives of Mining Sciences","volume":null,"pages":null},"PeriodicalIF":1.2000,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Archives of Mining Sciences","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.24425/ams.2024.150339","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MINING & MINERAL PROCESSING","Score":null,"Total":0}
引用次数: 0
Abstract
One of the techniques commonly applied today for deep foundation construction is based on self-drilling injection micropiles. Micropiles are structural elements intended primarily for reinforcing foundations and buildings, particularly under difficult terrain conditions. The goal of the tests presented herein is to inspect the fatigue resistance, strength and ductility of injection micropiles formed from 28Mn6 steel at loads significantly exceeding the values defined for the fatigue test in the requirements of the relevant European Assessment Document (EAD). The test results and the micropile bar strain model εM presented in this paper are primarily of interest to designers for the purposes of determining the fatigue resistance of steel micropiles, which find particular application in land degraded by mining activity that is characterised by frequent terrain vibration and mining-induced tremors. None of the R25N injection micropile bars failed during the fatigue resistance testing at 2·106 cycles at a load Fu = 0.7·FRe0.2 (under the yield strength of the 28Mn6 steel) as well as at Fu = 1.0·FRe0.2 and Fu = 1.2·FRe0.2, where the bars operated at the limit of and significantly above the load FRe0.2 which results in stress at the yield point of the 28Mn6 steel. Furthermore, the bar tests conducted at static and cyclic loading demonstrated the high strength and good ductility of the 28Mn6 steel.
期刊介绍:
Archives of Mining Sciences (AMS) is concerned with original research, new developments and case studies in mining sciences and energy, civil engineering and environmental engineering. The journal provides an international forum for the publication of high quality research results in:
mining technologies,
mineral processing,
stability of mine workings,
mining machine science,
ventilation systems,
rock mechanics,
termodynamics,
underground storage of oil and gas,
mining and engineering geology,
geotechnical engineering,
tunnelling,
design and construction of tunnels,
design and construction on mining areas,
mining geodesy,
environmental protection in mining,
revitalisation of postindustrial areas.
Papers are welcomed on all relevant topics and especially on theoretical developments, analytical methods, numerical methods, rock testing, site investigation, and case studies.