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TitleBiaxial tests of some overcored samples from AECL's underground research laboratory, Lac du Bonnet, Manitoba
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorLau, J S O
SourceCanada Centre for Mineral and Energy Technology, Mining Research Laboratories, Division Report 89-55 (TR), 1989, 64 pages, Open Access logo Open Access
PublisherEnergy, Mines and Resources Canada
Mediapaper; on-line; digital
File formatpdf
SubjectsScience and Technology; Nature and Environment; rock stress analyses; bedrock geology; lithology; igneous rocks; intrusive rocks; granites; nuclear waste disposal; nuclear energy
Illustrationstables; plots
Released1989 05 01; 2020 07 28
AbstractIn support of Atomic Energy of Canada Limited's in situ stress measurement program at the Underground Research Laboratory, biaxial tests and biaxial tests with axial load were conducted at the Canada Centre for Mineral and Energy Technology (CANMET) to examine the effect of axial and side loads on the strains measured on the inside and on the outside of overcored rock samples obtained in the URL and the elastic constants derived from them. The rock is a massive, grey, medium to coarse grained porphyritic granite. With axial loading, cell pressures as high as 36 MPa could be applied on the overcored specimens without causing disking. Without axial loading, a cell pressure as low as 13 MPa could cause disking. There were fairly good agreements between the secant Young's modulus values obtained on the outside and on the inside of the hollow rock specimens in both the biaxial tests and the biaxial tests with axial load. The secant Young's modulus values in the axial direction were found to be approximately 10 GPa higher than the modulus values in the circumferential direction, indicating that the rock specimens were highly anisotropic and the anisotropy was probably caused by the microcracks present in the specimens. The secant Young's modulus values obtained in the biaxial tests with axial load at pressure levels above 28 MPa were very high. Selected uniaxial compression tests should be conducted on the overcored specimens to check the effect of end constraint on the modulus values as well as to shed some light on the discrepancies in some of the axial strain readings.

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