Asperity (geotechnical engineering)
In geotechnical engineering and contact mechanics the term asperity is used to refer to individual features of unevenness (roughness) of the surface of a discontinuity, grain, or particle with heights in the range from approximately 0.1 mm to the order of metres. Below the asperity level, surface interactions are normally considered to be a material property, arising from mechanisms of adhesion and repulsion at the atomic scale (often accounted for by material friction, atomic friction or molecular friction).[1]
Dilation[edit]
An often used definition for asperities in geotechnical engineering:
Unevenness of a surface are asperities if these cause dilation if two blocks with in between a discontinuity with matching asperities on the two opposing surfaces (i.e. a fitting discontinuity) move relative to each other, under low stress levels that do not cause breaking of the asperities.
Contrast with asperity in materials science[edit]
Materials science recognizes asperities ranging from the sub-visual (normally less than 0.1 mm) to the atomic scale.
See also[edit]
References[edit]
- ^ Patton, F.D. (25 Sep – 1 Oct 1966). "Multiple Modes of Shear Failure in Rock". In Rocha, M. (ed.). Proc. 1st Congress of International Society for Rock Mechanics (ISRM). Vol. 1. Lisbon, Portugal: Laboratório Nacional de Engenharia Civil, Lisboa, Portugal. pp. 509–513. OL 19662608M.
Further reading[edit]
- ASTM D5607 (2008). Standard Test Method for Performing Laboratory Direct Shear Strength Tests of Rock Specimens Under Constant Normal Force. ASTM International, West Conshohocken, PA, 2008. p. 450. doi:10.1520/D5607-08.
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- Price, D.G. (2008). De Freitas, M.H. (ed.). Engineering Geology: Principles and Practice. Springer. p. 450. ISBN 978-3-540-29249-4.
- Szymakowski, J.; Haberfield, C. (11–14 September 2001). "Preliminary results of direct shear testing of large scale, jointed, soft rock". In Sijing, W.; Bingjun, F.; Zhongkui, Z.L. (eds.). Frontiers of Rock Mechanics and Sustainable Development in the 21st Century, Proc. ISRM 2001 - 2nd ARMS. Beijing, China: Swets & Zeitlinger, Lisse, Netherlands, Taylor & Francis. pp. 257–260. ISBN 90-265-1851-X.