Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/77813
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dc.contributor.authorHashemi, S.en
dc.contributor.authorMelkoumian, N.en
dc.contributor.authorXu, C.en
dc.date.issued2012en
dc.identifier.citationProceedings: the 7th Australasian Congress on Applied Mechanics (ACAM 7), 9-12 December 2012, Adelaide: pp.884-894en
dc.identifier.isbn9781922107619en
dc.identifier.urihttp://hdl.handle.net/2440/77813-
dc.description.abstractAchieving an in-depth understanding of the behaviour of low cemented formations such as running sands around a cylindrical borehole is of significant importance in identifying stability problems, designing adequate borehole supports and choosing an efficient drilling method. This paper presents numerical investigations on failure modes of unsupported vertical cylindrical boreholes drilled through weak formations, i.e. low cemented sands where the movement of individual grains is not restricted by sufficient cementation. Distinct element method (DEM) was used for this study. The method enables to simulate sand grains and control normal and shear bonding between them. To simulate actual condition surrounding a borehole at a depth of 80m, a 2m x 2m x 2m cube made up of spherical particles with diameters ranging from 5mm to 70mm was constructed and analysed in the DEM code, PFC3D. The results showed that stress concentration developed in the ground due to the presence of a borehole leads to the formation of a damage zone around that borehole. When there is not sufficient bonding between the sand grains, the interaction between them results in their movement towards the borehole and the eventual collapse of the borehole wall. The effect of fluid flow on stability of boreholes has been studied as well. The cementation between sand grains is mainly caused by the presence of clay particles in the formation. The bonding strength between sand grains is an intrinsic or micro property of the bonding material and is very difficult to measure in laboratory conditions. The results obtained from current research will help to evaluate the effect of particle bonding on the mechanical behaviour of low cemented formations and develop methods to assess borehole stability during and after drilling through such formations.en
dc.description.statementofresponsibilityS. Saeid Hashemi, Noune Melkoumian and Chaoshui Xuen
dc.language.isoenen
dc.publisherEngineers Australiaen
dc.rightsCopyright status unknownen
dc.source.urihttp://search.informit.com.au/documentSummary;dn=129091780891685;res=IELENGen
dc.subjectBorehole stability; distinct element method; particle bonding; unconsolidated formationsen
dc.titleEffect of grain bonding on the stability of a borehole drilled though low cemented formationsen
dc.typeConference paperen
dc.identifier.rmid0020127335en
dc.contributor.conferenceAustralasian Congress on Applied Mechanics (7th : 2012 : Adelaide, S.A.)en
dc.publisher.placeCDROM / DVDROMen
dc.identifier.pubid20210-
pubs.library.collectionCivil and Environmental Engineering publicationsen
pubs.verification-statusVerifieden
pubs.publication-statusPublisheden
dc.identifier.orcidXu, C. [0000-0001-6662-3823]en
Appears in Collections:Civil and Environmental Engineering publications

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