A method to downscale joint surface roughness and to create replica series using 3D printed molds

Lauri Uotinen, Eero Korpi, Ari Hartikainen, Raphael Yorke, Juha Antikainen, Fredrik Johansson, Mikael Rinne

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

1 Citation (Scopus)
309 Downloads (Pure)

Abstract

In order to determine the in-situ shear strength of rock joints, large scale testing is required. However, this is both expensive and difficult to execute. One possible method to overcome this may be to use photogrammetry to capture large joint surface roughness in-situ and downscale it to replica samples, which could be sheared in laboratory. In this paper, as a first part in such a method, a technique to digitize surface roughness and to produce replica samples for laboratory shear testing from a larger joint sample are presented. First, a thin granitic rock slice with dimensions of 1.75 m x 0.95 m of granitic intact rock was chosen for the study. The joint surface is fresh and created through tensile induced splitting. The large joint sample is digitized using photogrammetry. Then, one full-scale 1.7 m x 0.6 m geometry is cropped from the digitized joint geometry and then subsamples at 10x, 7.5x, 5x, 2.5x and 1x scales. All sub-geometries are scaled down digitally to produce 0.17 m by 0.06 m geometries. The geometries are used to make casting molds both positive and negative to produce samples with perfect matedness. The casting molds are 3D printed in polylactic acid plastic and C60/75 concrete is cast to produce a replica series. In addition to the creation of this replica series, two pilot replicas are also tested using a portable shear box with a 0.5 MPa normal pressure. The results from the pilot rounds are presented and discussed. Finally, suggestions for future research are given.
Original languageEnglish
Title of host publicationISRM 13th International Congress on Rock Mechanics, Montreal, May 10-13, 2015
PublisherCanadian Institute of Mining, Metallurgy and Petroleum
Number of pages11
ISBN (Electronic)978-1-926872-25-4
Publication statusPublished - 2017
MoE publication typeA4 Article in a conference publication
EventISRM International Congress on Rock Mechanics - Montreal, Canada
Duration: 10 May 201513 May 2015
Conference number: 13

Conference

ConferenceISRM International Congress on Rock Mechanics
Abbreviated titleISRM
Country/TerritoryCanada
CityMontreal
Period10/05/201513/05/2015

Keywords

  • Joint
  • Crack
  • Fracture
  • Photogrammetry
  • 3D printing
  • Replica
  • Concrete
  • Shear Box

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