The note extends the analysis of the work of Cryer, who assumed the coefficient of permeability to be constant, taking into account the actual change of permeability with void ratio which invariably accompanies consolidation. Theoretical expressions are derived to evaluate the variation with time of the centre pore water pressure for a saturated porous sphere and comparisons are made with practical investigations using two very different soils in copper tailings and Florida phosphatic clay. Results showed that using finite strain analysis, taking the dependence of the coefficient of permeability on the void ratio into account, both the magnitude of the Mandel-Cryer effect and the rate of dissipation of pore pressure decrease with increasing stress. This result combined with those of previous work demonstrates that the differential decrease of permeability during consolidation is of dominant importance. This is due to a sudden and early drop in the skeleton permeability close to the drainage surface producing a throttling effect which reduces the rate of consolidation much more than the reducing drainage path increases it. Even with appreciable loading the Mandel-Cryer effect was more than 30 per cent for a Poisson's ratio of zero. (TRRL)

  • Availability:
  • Corporate Authors:

    Thomas Telford Limited

    London,   United Kingdom 
  • Authors:
    • Gibson, R E
    • Gorbeth, A
  • Publication Date: 1990-12

Media Info

  • Features: References;
  • Pagination: p. 627-631
  • Serial:
    • Volume: 40
    • Issue Number: 4
    • Publisher: Thomas Telford Limited
    • ISSN: 0016-8505

Subject/Index Terms

Filing Info

  • Accession Number: 00619951
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Mar 31 1992 12:00AM