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An innovative index to assess clogging potential

  • Author / Creator
    Zhou, Yang
  • Clogging frequently occurs during underground excavation using tunnel boring machines (TBMs), and can cause severe schedule delays and cost overruns on projects. However, an index to quantitatively describe clogging potential has not been standardized. This paper presents a new index to indicate clogging potential based on the results of a mixing test, and the authors have also conducted sensitivity analysis to understand the effect of different types and weights of soil and different size of beater on the variability of the index. The new index is also compared with the stickiness ratio based on standard deviation of the weight of soil stuck on the beater over W/Ac and stickiness ratio, respectively, to show the advantage of using the new index. The results show that although the mass of soil that sticks to the mixing tool varies, assessing clogging potential using the new index, W/Ac, can give more repeatable results, since it eliminates the impact of beater size and mass of soil. In addition, the clogging potential of different types of soil can be differentiated using W/Ac, and the average standard deviation of the test using different beater sizes and masses of soil are smaller using the index W/Ac compared to using the stickiness ratio. This paper provides a reliable and straightforward index to assess clogging potential easily and simply based on the results of a mixing test.

  • Subjects / Keywords
  • Graduation date
    Fall 2020
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/r3-4nq5-tb72
  • License
    Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.