Abstract
Failure of rock close to a free surface is reproduced in laboratory tests on two types of sandstone. Digital image correlation is used to study the in-plane displacement fields prior to and during the successive formation of surface-parallel fractures. The axial and lateral displacements suggest that the displacement gradient is uniform in both directions at early loading stages; as the axial load increases, the free-face effect starts to influence the displacement contours, especially the lateral displacement field. Localised damage forms a spall before reaching peak stress. Using a simple model, a rock brittleness index is proposed as the ratio of uniaxial compressive strength and surface instability peak stress.
Original language | English (US) |
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Pages (from-to) | 161-166 |
Number of pages | 6 |
Journal | Geotechnique |
Volume | 66 |
Issue number | 2 |
DOIs | |
State | Published - Feb 1 2016 |
Keywords
- Failure
- Laboratory tests
- Rocks/rock mechanics
- Strain localisation