Research Outputs (Civil and Environmental Engineering)

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Information regarding content on this collection please contact : Salome Potgieter by email : salome.potgieter@wits.ac.za or Tel : 011 717 1961

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Browsing Research Outputs (Civil and Environmental Engineering) by Type "Other"

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    Assessment of two cone penetration test based methods for evaluating the liquefaction potential of tailings dams.
    (2013-06-12) Torres Cruz, Luis Alberto
    The stability of tailings dams is of great importance to the mining industry. It is well known that soil liquefaction is one of the mechanisms that can compromise the stability of such structures. Given the difficulty of extracting undisturbed samples of any cohesionless material, the use of in situ tests to assess liquefaction potential has been intensely researched. The purpose of this work was to assess the applicability to tailings dams of two CPT-based liquefaction assessment methodologies, namely, the Robertsonbased and the Olson and Stark methodologies. Ten case histories were evaluated. When considering triggering of liquefaction, the Robertson-based and Olson and Stark methodologies correctly predicted the behaviour of four out of five and seven out of ten case histories, respectively. When considering the onset of flow failure, the Olson and Stark methodology correctly predicted the behaviour in four of seven case histories for which a post-triggering analysis was made. The results are useful in understanding the shortcomings of implementing these methodologies on TSFs and the limits of their predictive power.
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    Reflections on future needs in concrete durability research and development.
    (CRC Press, Taylor & Francis Group, 2008) Ballim, Y.; Alexander, M.G.; Beushausen, H.D.; Moyo, P.
    There is no doubt that, over the past two decades, we have made enormous advances in the understanding and practice of concrete durability. Spurred by the often experienced early deterioration of reinforced concrete structures, with high capital investment for repair and rehabilitation, conceptions of design for durability have gained an increasingly higher level of importance in recent years. Durability design is beginning to be considered of equal importance as design for safety and serviceability. Nevertheless, durability concerns remain and early deterioration still attracts much expenditure. This paper is aimed at identifying important developments made in the field of concrete durability during the past two decades. Based on current design practice and current knowledge, future research and development needs are discussed, focusing on the influences of constituent materials, deterioration prevention methods, service life modelling of reinforced concrete structures, and performance-based test methods.