THE DEVELOPMENT OF PORE WATER PRESSURE AT THE SUBGRADE-SUBBASE INTERFACE OF A HIGHWAY PAVEMENT AND ITS EFFECT ON PUMPING OF FINES

This paper presents experimental and numerical methods to investigate the development of pore water pressure at the subgrade-subbase interface. This phenomenon is the main factor contributing to the occurrence of 'pumping', which may be defined as the migration of fines from a fine-graded subgrade soil into the upper granular layers of road pavements under moving traffic. The authors developed the Fundamental Pumping Test, to enable the measurement of both static and cyclic pore water pressures under various subgrade-subbase interface conditions. Its experimental results were supplemented by finite element techniques, which enabled the derivation of a mathematical estimate of the pore water pressure and hydraulic gradient under a typical subbase particle in the presence of a geotextile layer. It was found that the penetration of subbase particles into the subgrade soil and the upward plastic flow of subgrade soil were reduced by placing a geotextile at the subgrade-subbase interface. High permeability geotextiles allow quick dissipation of cyclic pore pressure. Thick geotextiles reduce pumping, and compressible geotextiles cause higher cyclic pore pressure and higher pumping.

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  • Corporate Authors:

    Elsevier

    The Boulevard, Langford Lane
    Kidlington, Oxford  United Kingdom  OX5 1GB
  • Authors:
    • ALOBAIDI, I
    • HOARE, D J
  • Publication Date: 1996-2

Language

  • English

Media Info

  • Features: References;
  • Pagination: p. 111-35
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00729174
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Dec 12 1996 12:00AM