Use of the cone penetration test to assess the liquefaction potential of tailings storage facilities

dc.contributor.authorTorres Cruz, Luis Alberto
dc.date.accessioned2017-02-10T13:40:34Z
dc.date.available2017-02-10T13:40:34Z
dc.date.issued2016
dc.descriptionA dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy, 2016en_ZA
dc.description.abstractThe performance in tailings storage facilities (TSFs) of three methods based on the cone penetration test (CPT) to assess liquefaction potential is explored. For two of these methods the investigation highlights potential limitations mostly related with the experimental data that supports some of the equations used by the methods. However, the methodologies yielded mostly correct performance predictions when implemented on TSF case histories in which an undrained response is believed to have occurred. The positive performance of both methodologies must be tempered by the limitations identified in the methods. The steady state line (SSL) is an input of the third method considered. Accordingly, the correlation between the SSL and soil index parameters was investigated using a database of 151 non-plastic soiltypes compiled from data previously reported in the literature. The SSLs were modelled in void ratio (e) - mean effective stress (p') space, using a logarithmic equation. The y-intercept of the SSL is termed Γ, and the slope is termed λ. A direct, and linear (R2 = 0.74) correlation between the minimum void ratio (emin) and Γ was found. Although previous research has explored the effect of non-plastic fines on the SSL, the analysis presented herein shows that the Γ-emin correlation is independent of fines content. The correlation is also independent of the angularity of the particles provided that these are bulky, as opposed to platy. A direct λ-emin correlation was also found; however this correlation is much weaker and probably obscured by uncertainties in void ratio measurements. Triaxial testing was conducted to determine the SSLs of three tailings soiltypes obtained from a single TSF. The trends observed in the resulting SSLs are in agreement with the Γ-emin and λ-emin correlations from the database. An assessment was made of the sensitivity of the third method, which is based on a state parameter (ψ), to variations in λ throughout a single TSF. It was found that in some TSFs, the variations of λ are small enough to be disregarded without significantly affecting the accuracy of ψ. However, in other TSFs it is necessary to estimate how λ varies throughout the deposit. iiien_ZA
dc.description.librarianCK2017en_ZA
dc.format.extentOnline resource (255 leaves)
dc.identifier.citationTorres Cruz, Luis Alberto (2016) Use of the cone penetration test to assess the liquefaction potential of tailings storage facilities, University of Witwatersrand, Johannesburg, <http://wiredspace.wits.ac.za/handle/10539/22007>
dc.identifier.urihttp://hdl.handle.net/10539/22007
dc.language.isoenen_ZA
dc.subject.lcshSoil penetration test
dc.subject.lcshSoil liquefaction
dc.subject.lcshShear strength of soils--Testing
dc.subject.lcshTailings (Metallurgy)--Storage
dc.titleUse of the cone penetration test to assess the liquefaction potential of tailings storage facilitiesen_ZA
dc.typeThesisen_ZA
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