Comparative behaviour of an undisturbed clay under triaxial and plane strain conditions

• Main Author: Vaid, Yoginder P.
• Language: English
• Published: University of British Columbia 2011
• Subjects: Strains and stresses; Clay
• Online Access: http://hdl.handle.net/2429/34037

Many field problems in soils approximate plane strain conditions. Conventional laboratory practice, however, consistently uses triaxial compression testing for evaluating strength and deformation properties of soils. Possible differences between triaxial and plane strain behaviour of natural soils have so far received little attention. New plane strain and K₀-triaxial apparatuses have been designed in which it is now possible to shear samples under various stress paths. A series of triaxial and plane strain tests were performed on identically K₀-consolidated samples of an undisturbed, sensitive, marine clay. Drained and undrained compression and extension tests under both increasing and decreasing stresses were carried out. Similar series of tests were also made on heavily overconsolidated specimens. It is demonstrated that the use of triaxial test results where plane strain conditions prevail invariably leads to an overestimate of deformations and an underestimate of strength. Methods to estimate strains in undrained plane strain shear from the results of triaxial tests under identical stress paths have been developed. Similarly, strains during drained plane strain shear of normally consolidated clay could be predicted from drained and undrained triaxial results, using an extended form of Rendulic's hypothesis. === Applied Science, Faculty of === Civil Engineering, Department of === Graduate