FAST SHEARING OF PRE-EXISTING SHEAR ZONES IN SOIL

The paper presents results from a laboratory investigation into the influence of fast rates of displacement on the residual strength of soil. This influence was studied in the ring shear apparatus. Shear zones were formed by slow drained shearing and then tested at alternately fast and slow rates of displacement. Results from a wide range of natural soils are presented. All soils show initially an increase in strength when resheared at fast rates of displacement. The strength then tends to decrease with fast displacement to a minimum value - the fast residual strength. Three types of rate effects on the residual strength are identified: a positive rate effect in soils showing a fast residual strength higher than the slow residual; a neutral rate effect in soils showing a constant fast residual strength, equal to the slow residual, irrespective of rate of displacement; and a negative rate effect in soils showing a significant drop in fast residual strength below the slow residual when sheared at rates higher than a critical value. The relation between the types of displacement rate effect and the basic shearing modes of slow residual strength (turbulent, transitional and sliding) is considered and the causes of the negative rate effect and the influence of the apparatus on it have been investigated. The practical implications of the results in the context of slope stability and displacement piles are also discussed. (A)

  • Availability:
  • Corporate Authors:

    Thomas Telford Limited

    London,   United Kingdom 
  • Authors:
    • Tika, T E
    • VAUGHAN, P R
    • LEMOS, LJLJ
  • Publication Date: 1996-6

Language

  • English

Media Info

  • Features: References;
  • Pagination: p. 197-233
  • Serial:
    • GEOTECHNIQUE
    • Volume: 46
    • Issue Number: 2
    • Publisher: Thomas Telford Limited
    • ISSN: 0016-8505

Subject/Index Terms

Filing Info

  • Accession Number: 00726638
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Oct 28 1996 12:00AM