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dc.contributor.authorBasnet, Chhatra Bahadur
dc.contributor.authorPanthi, Krishna Kanta
dc.date.accessioned2018-05-30T07:43:01Z
dc.date.available2018-05-30T07:43:01Z
dc.date.created2018-05-29T10:59:17Z
dc.date.issued2018
dc.identifier.citationJournal of Rock Mechanics and Geotechnical Engineering. 2018, 10 486-512.nb_NO
dc.identifier.issn1674-7755
dc.identifier.urihttp://hdl.handle.net/11250/2499707
dc.description.abstractNorwegian hydropower industry has more than 100 years of experiences in constructing more than 4000 km-long unlined pressure shafts and tunnels with maximum static head of 1047 m (equivalent to almost 10.5 MPa) reached at unlined pressure tunnel of Nye Tyin project. Experiences gained from construction and operation of these unlined pressure shafts and tunnels were the foundation to develop design criteria and principles applied in Norway and some other countries. In addition to the confinement criteria, Norwegian state-of-the-art design principle for unlined pressure shaft and tunnel is that the minor principal stress at the location of unlined pressure shaft or tunnel should be more than the water pressure in the shaft or tunnel. This condition of the minor principal stress is prerequisite for the hydraulic jacking/splitting not to occur through joints and fractures in rock mass. Another common problem in unlined pressure shafts and tunnels is water leakage through hydraulically splitted joints or pre-existing open joints. This article reviews some of the first attempts of the use of unlined pressure shaft and tunnel concepts in Norway, highlights major failure cases and two succe ssful cases of significance, applies Norwegian criteria to the cases and reviews and evaluates triggering factors for failure. This article further evaluates detailed engineering geology of failure cases and also assesses common geological features that could have aggravated the failure. The minor principal stress is investigated and quantified along unlined shaft and tunnel alignment of six selected project cases by using three dimensional numerical model. Furthermore, conditions of failure through pre-existing open joints by hydraulic jacking and le akage are assessed by using two-dimensional fluid flow analysis. Finally, both favorable and unfavorable ground conditions required for the applicability of Norwegian confinement criteria in locating the unlined pressure shafts and tunnels for geotectonic environment different from that of Norway are highlighted.nb_NO
dc.description.abstractAnalysis of unlined pressure shafts and tunnels of selected Norwegian hydropower projectsnb_NO
dc.language.isoengnb_NO
dc.publisherElseviernb_NO
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 Internasjonal*
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/deed.no*
dc.titleAnalysis of unlined pressure shafts and tunnels of selected Norwegian hydropower projectsnb_NO
dc.typeJournal articlenb_NO
dc.typePeer reviewednb_NO
dc.description.versionpublishedVersionnb_NO
dc.source.pagenumber486-512nb_NO
dc.source.volume10nb_NO
dc.source.journalJournal of Rock Mechanics and Geotechnical Engineeringnb_NO
dc.identifier.doihttps://doi.org/10.1016/j.jrmge.2017.12.002
dc.identifier.cristin1587355
dc.relation.projectNorges forskningsråd: 257588nb_NO
dc.description.localcode2018 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).nb_NO
cristin.unitcode194,64,90,0
cristin.unitnameInstitutt for geovitenskap og petroleum
cristin.ispublishedtrue
cristin.fulltextoriginal
cristin.qualitycode1


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Attribution-NonCommercial-NoDerivatives 4.0 Internasjonal
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