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dc.contributor.authorPujades Garnes, Estanislao
dc.contributor.authorVázquez Suñé, Enric
dc.contributor.authorCarrera Ramírez, Jesús
dc.contributor.authorVilarrasa Riaño, Víctor
dc.contributor.authorDe Simone, Silvia
dc.contributor.authorJurado Elices, Anna
dc.contributor.authorLedesma Villalba, Alberto
dc.contributor.authorRamos Schneider, Gonzalo
dc.contributor.authorLloret Morancho, Antonio
dc.contributor.otherUniversitat Politècnica de Catalunya. Departament d'Enginyeria del Terreny, Cartogràfica i Geofísica
dc.contributor.otherUniversitat Politècnica de Catalunya. Departament d'Enginyeria de la Construcció
dc.identifier.citationPujades, E. [et al.]. Deep enclosures versus pumping to reduce settlements during shaft excavations. "Engineering geology", 04 Febrer 2014, vol. 169, p. 100-111.
dc.description.abstractDeep excavations in aquifers may be constructed by combining pumping with the cut and cover method. The enclosures are often deepened more than structurally needed, in order to diminish the risk of heave or fluidisation inside the excavation, and to reduce pumping rates and the associated settlements outside jet-grouting piles are sometimes adopted for lengthening. We analysed the water-proofing efficiency of jet-grouting and the need for water isolation in preconsolidated sediments. We used data obtained from two shaft excavations during the construction of the high speed train tunnel in Barcelona, located adjacent to the Sagrada Familia Basilica. Jet-grouting was characterised using pumping tests before and after the construction of the enclosure. The effectiveness of deepened enclosures was evaluated by comparing settlements caused and discharges required for several dewatering scenarios. Differences between them lie in the depth of the enclosures. Settlements were calculated analytically, using the drawdown obtained from a hydrogeological model, and numerically employing a hydro-mechanical model. Results show that jet-grouting reduced the permeability of the soil (90% reduction, from 5.5 to 0.6 m/d). However, this reduction only affected the pile area, so that the necessary pumping rate and the settlements outside the enclosure were only reduced by 40%. Results also show that settlements due to groundwater pumping are fairly smooth (i.e., differential settlements are small) with low absolute values. Moreover, they recover when pumping ceases. This rather elastic and stiff behaviour reflects the preconsolidated nature of the sediments in Barcelona and the fact that drawdowns concentrate at depth, where the soil is most compact, causing little change in effective stress near the soil surface. Under these conditions, pumping does not pose a serious risk to settlements, and excavation costs can be lowered by constructing the enclosure at the minimum depth required structurally. Also, an intense control of the pumping process may help reducing the conventional safety factors against heave.
dc.format.extent12 p.
dc.subjectÀrees temàtiques de la UPC::Enginyeria civil::Geotècnia::Mecànica de sòls
dc.subjectÀrees temàtiques de la UPC::Edificació::Tècniques i sistemes constructius
dc.subject.lcshShaft sinking
dc.subject.otherDiaphragm walls
dc.subject.otherAQUIFER PARAMETERS
dc.subject.otherDIAPHRAGM WALLS
dc.subject.otherSALINE MEDIA
dc.subject.otherSOFT SOIL
dc.titleDeep enclosures versus pumping to reduce settlements during shaft excavations
dc.subject.lemacPous de mines -- Perforació
dc.contributor.groupUniversitat Politècnica de Catalunya. TE - Tecnologia d'Estructures
dc.contributor.groupUniversitat Politècnica de Catalunya. MSR - Mecànica del Sòls i de les Roques
dc.description.peerreviewedPeer Reviewed
dc.rights.accessRestricted access - publisher's policy
dc.description.versionPostprint (published version)
upcommons.citation.authorPujades, E.; Vazquez-Suñe, E.; CARRERA, J.; Vilarrasa, V.; De Simone, S.; Jurado, A.; Ledesma, A.; Ramos, G.; Lloret, A.
upcommons.citation.publicationNameEngineering geology

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