Encyclopedia of Engineering Geology

2018 Edition
| Editors: Peter T. Bobrowsky, Brian Marker

Poisson’s Ratio

  • Jeffrey R. KeatonEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-3-319-73568-9_225


Poisson’s ratio is the name given to a ratio of lateral strain to axial strain. Its recognition as a property of materials is attributed to Siméon-Denis Poisson (1781–1840), a French mathematician and student of Laplace. Uniaxial extension of a solid rod causes it not only to elongate a small amount but also to become more slender or to undergo a reduction in diameter. Conversely, uniaxial compression of a solid rod or rock core sample causes it to shorten a small amount, but also to expand in diameter or become thicker. Therefore, principal stress in only one direction (uniaxial extension or compression) produces strain in all three directions. Hooke’s law explained the proportional change in length of a spring to the application of a load. Generalized Hooke’s law (Pariseau, 2012) recognizes that strain ( ε x = Δ l/ l o) is proportional to the applied stress ( σ x), and the constant of proportionality for an isotropic material being stressed and strained in the elastic range of...
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  1. ASTM (2014) Standard test methods for compressive strength and elastic moduli of intact rock core specimens under varying states of stress and temperatures. American Society for Testing and Materials Test Designated D7012-14. http://www.astm.org/Standards/D7012.htm. Accessed April 2016
  2. Eberhardt E (2009) Stress & strain: a review. Course notes EOSC 433, University of British Columbia, Vancouver. https://www.eoas.ubc.ca/courses/eosc433/lecture-material/StressStrain-Review.pdf. Accessed April 2016
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Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Amec Foster WheelerLos AngelesUSA