Wave velocity measurements in three directions on axially loaded water-saturated granite and gneiss core specimens

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Conference article in proceedings
Date
2019-09-03
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Language
en
Pages
8
1638-1645
Series
Rock Mechanics for Natural Resources and Infrastructure Development - full papers, Proceedings in Earth and geosciences series, Volume 6
Abstract
The density, porosity and mechanical properties from uniaxial compression and Brazilian tests along with measurements of the P- and S-wave velocities in axial and two lateral directions at unloaded state and at increasing axial load were conducted on cylindrical cores of veined gneiss and granitic pegmatoid. The specimens were sampled close to a tunnel wall (0.1– 1.7 m depth) with the aim to find if there is an increasing amount of microcracks due to the excavation in a zone near the surface. Evidence of microcracks was found via the mechanical tests and the wave velocity measurements, due to increased mechanical stiffness and increasing wave velocities at loading. Anisotropy in in the gneiss specimens and also in the granitic pegmatoid was detected and measured via strain and wave velocity measurements. No clear evidence was found of increased amount of microcracks closer to the tunnel wall.
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Citation
Jacobsson , L , Kjell , G , Kiuru , R & Suikkanen , J 2019 , Wave velocity measurements in three directions on axially loaded water-saturated granite and gneiss core specimens . in S A B da Fontoura , R J Rocca & J F Pavón Mendoza (eds) , Rock Mechanics for Natural Resources and Infrastructure Development - full papers : Proceedings of the 14th International Congress on Rock Mechanics and Rock Engineering (ISRM 2019), September 13-18, 2019, Foz do Iguassu, Brazil . Proceedings in Earth and geosciences series , vol. 6 , CRC Press , pp. 1638-1645 , ISRM International Congress on Rock Mechanics and Rock Engineering , Iguassu Falls , Brazil , 13/09/2019 .