Die natürliche Bruchcharakteristik (NBC) von Gesteinen in der Sprengtechnik

Translated title of the contribution: The natural breakage characteristics (NBC) of rocks in blasting

Andreas Johannes Grasedieck

Research output: ThesisDoctoral Thesis

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Abstract

The NBC is well known in mechanical comminution processes. The aims of this Thesis were first to validate the NBC for rock-blasting, second to develop a procedure for a measurable definition of the NBC and third to find those material parameters which are responsible for the existence of a NBC. The NBC is defined as a measurable parameter through the evaluation of the self similarity. New definitions like 'highly self similar', 'self similar' and 'weakly self similar' have been introduced. The NBC of a rock-material is not defined only by the characteristics of the particle size distribution curves in log-log scale but also by the position and size of the minimum slope of the particle size distribution curve called 'Local Minimum'(LM). The LM is unlike the gradient of the Local Slopes independent of the comminution-process and the scale of the samples investigated. Preparations of polished thin sections from material from the different grain size classes (<2 mm) were used to determine distribution curves from single grains and aggregates. The grain size where the proportion of single grains falls below a value of 50 % is the position of the LM. Thin-sections of not comminuted material have been prepared. From there in-situ grain size-distributions have been determined. The determined maximum grain size of each material correlates with the minima described above. Consequently the LM, which is caused by a relative diminution of grains in the certain grain size-class, could be defined by three measurable parameters, which define a material-structure.
Translated title of the contributionThe natural breakage characteristics (NBC) of rocks in blasting
Original languageGerman
QualificationDr.mont.
Supervisors/Advisors
  • Moser, Peter, Assessor A (internal)
  • Ouchterlony, Finn, Assessor B (external)
Publication statusPublished - 2006

Bibliographical note

embargoed until null

Keywords

  • natural breakage characteristics
  • NBC
  • blasting technique
  • model scaled blasting test
  • full scaled blasting test
  • grainsize distribution
  • self-similar

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