THE VALUE OF POISSON'S RATIO IN SATURATED SOILS AND ROCKS STRESSED UNDER UNDRAINED CONDITIONS

The theoretical implications of the wide variation in soil and rock compressibility on undrained Poisson's ratio are examined. Expressions are derived for this parameter in saturated porous materials for the cases of both isotropic and anisotropic structures. It is demonstrated that the undrained Poisson's ratio for an isotropic structure, muu, only has the classical value of one-half for the special condition of pore pressure parameter b exactly equal to 1 and owes its high value not only to the low value of undrained compressibility but also to the low value of undrained Young's modulus. For an anisotropic structure with an axis of symmetry vertical, the value of undrained Poisson's ratio for strain in any horizontal direction due to a direct vertical stress is also equal to one-half irrespective of the degree of anisotropy for the special condition of b equal to 1. Since, in the absence of special tectonic conditions, this is the Poisson's ratio measured in a conventional cylindrical compression test on a sample cut with its axis vertical, the presence of anisotropy may be masked in a soil with b approaching 1. A numerical example is given which illustrates the large influence of anisotropy on the undrained values of Poisson's ratio for other directions of loading. /Author/TRRL/

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00168505
• Corporate Authors:

  Institution of Civil Engineers

  One Great George Street, Westminster
  London,   United Kingdom  SW1P 3AA
• Authors:
  • Bishop, A W
  • HIGHT, D W
• Publication Date: 1977-9

Language

• French

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 369-384
• Serial:
  • GEOTECHNIQUE
  • Volume: 27
  • Issue Number: 3
  • Publisher: Thomas Telford Limited
  • ISSN: 0016-8505

Subject/Index Terms

• TRT Terms: Anisotropic materials; Compressibility; Isotropic materials; Isotropy; Modulus of elasticity; Poisson distributions; Poisson ratio; Pore pressure; Rock mechanics; Rocks; Saturated soils; Soils; Stresses; Structural analysis; Testing
• Uncontrolled Terms: Undrained conditions; Undrained soils
• Old TRIS Terms: Anisotropic mass; Isotropic mass; Poissons ratio
• ITRD Terms: 5905: Compressibility; 5917: Isotropic; 5924: Poisson's ratio; 4154: Rock; 4156: Soil; 5573: Stress analysis; 5782: Undrained soil
• Subject Areas: Geotechnology; Highways; I43: Rock Mechanics;

Filing Info

• Accession Number: 00168138
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Files: ITRD, TRIS
• Created Date: Jun 28 1978 12:00AM