CONSOLIDATION CHARACTERISTICS OF CLAYS FROM SELF-BORING PRESSUREMETER TESTS . FIELD TESTING IN ENGINEERING GEOLOGY. PROCEEDINGS OF THE TWENTY-FOURTH ANNUAL CONFERENCE OF THE ENGINEERING GROUP OF THE GEOLOGICAL SOCIETY, SUNDERLAND POLYTECHNIC, SEPTEMBER 4-8 1988

This paper discusses work carried out at the Science and Engineering Research Council's Bothkennar soft clay site into the effect of permeability on the results of the self boring pressuremeter holding test. Cambridge Self Boring Pressuremeter (CSBP) tests were carried out at location to obtain profiles of horizontal stress, shear modulus, and strength. Undrained tests were carried out at 1.0 m intervals down to a depth of 20.0 m, the base of the clay. Four holding tests were carried out at depths of 3.8, 9.8, 14.8 and 18.8 m. The tests were interpreted using total pressure observations. A parametric study of the effects of permeability on the test at 18.8 m was also undertaken. This used the CAMPE program, which uses a finite element technique based on three-node elements, with radial displacement and pore pressure considered to be quadratic functions of the radial coordinates. The soil was modelled as Cam-clay. The problem was modelled as a hollow cylinder of internal diameter 0.083 m (corresponding to that of the pressuremeter) and external diameter 9.74 m. The inner boundary was assumed to be impermeable. Both permeable and impermeable outer boundaries were investigated and the results were similar. A comparison is made between the use of pore and total pressure decay in the analysis. The field tests show that total pressure during expansion of a pressuremeter membrane decays while the membrane is held fixed as in the holding test. Initial numerical studies show that the rate of decay of pore pressure and total pressure are similar within experimental bounds. Thus the total pressure decay curve can be used to evaluate consolidation characteristics of clays, which overcome problems with the accurate monitoring of water pressure. For the covering abstract of the conference see IRRD 832042.

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    GEOLOGICAL SOCIETY PUBLISHING HOUSE

    UNIT 7, BRASSMILL ENTERPRISE CENTRE, BRASSMILL LANE
    BATH,   United Kingdom  BA1 3JN
  • Authors:
    • CLARKE, B G
  • Publication Date: 1990

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  • English

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  • Accession Number: 00607146
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • ISBN: 0-903317-51-6
  • Files: ITRD, TRIS
  • Created Date: Mar 31 1991 12:00AM