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- Andersson, J. C., et al.
(författare)
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Modeling the Äspö Pillar stability experiment
- 2010
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Ingår i: Rock Mechanics in Civil and Environmental Engineering - Proceedings of the European Rock Mechanics Symposium, EUROCK 2010. - 9780415586542 ; , s. 787-790
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Konferensbidrag (refereegranskat)abstract
- This paper presents results of the 1st stages ofTaskAof the Decovalex 2011 project, the numerical modeling of the Äspö Pillar Stability experiment performed by the Äspö Hard Rock Laboratory of the Swedish Nuclear Fuel and Waste Management Company (SKB). The objective is to perform back calculation of the Äspö pillar behavior using state of the art numerical modeling techniques for the material behavior. The work is divided into three stages and it is the first stage of thework that will be presented in this paper. Seven international teams from six different countries participated in the task and contributed to the results presented in this paper, concerning back calculation of uniaxial and triaxial compressive core testing and elastic back calculation of the stress path for excavation-induced stresses. The results are useful for understanding the occurrence of spalling in the upper part of the pillar during excavation and the stress path modeling gives the first approximation of the yielding strength of the pillar. The calculated results agree well with observations measured during experiment.
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- Uotinen, L. K. T., et al.
(författare)
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A method to downscale joint surface roughness and to create replica series using 3D printed molds
- 2017
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Ingår i: 13th ISRM International Congress of Rock Mechanics. - : International Society for Rock Mechanics. - 9781926872254
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Konferensbidrag (refereegranskat)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 fullscale 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.
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