STRENGTH AND DEFORMATION PARAMETERS FROM PRESSUREMETER TESTS IN CLAY . 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 article describes a laboratory simulation of in situ pressuremeter tests in clay in order to ascertain the effects of varying the test procedure on the results obtained. A large diameter triaxial cell was modified so that hollow cylindrical clay specimens could be subjected to internal and external pressures independently. Soil specimens were taken from Kaolin clay beds prepared by one dimensional consolidation of a slurry under a constant vertical stress. These were then reconsolidated to a higher mean stress than previously experienced by applying equal internal and external pressures in the triaxial cell. The situation prior to expansion thus simulated a "perfect" insertion of a self boring pressuremeter. During expansion radial plane strain conditions were maintained, and no drainage from the specimen was allowed. Stress tests were carried out by applying a water pressure inside the cavity in increments. A series of tests was carried out in which: (a) the pressure increments were varied while the holding time was constant; and (b) the pressure increments were held constant while the holding interval varied. Cavity pressure and volume, and pore water pressure at both the cavity boundary and at different positions within the clay were recorded. Strain control tests were carried out using a standard Cambridge self boring pressuremeter control unit. The results clearly demonstrate the influence of time dependent phenomena (consolidation and creep) on the pressuremeter expansion curves and the derived undrained strength and shear modulus values. These findings were confirmed by the results obtained using the Cambridge Self Boring Pressuremeter. Recommendations are made for test procedures which minimize these effects. For the covering abstract of the conference see IRRD 832042.

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• Corporate Authors:

  GEOLOGICAL SOCIETY PUBLISHING HOUSE

  UNIT 7, BRASSMILL ENTERPRISE CENTRE, BRASSMILL LANE
  BATH,   United Kingdom  BA1 3JN
• Authors:
  • ANDERSON, W F
  • PYRAH, I C
  • Pang, L S
• Publication Date: 1990

Language

• English

Media Info

• Pagination: p. 23-31
• Serial:
  • Publication of: GEOLOGICAL SOCIETY PUBLISHING HOUSE
  • Publisher: GEOLOGICAL SOCIETY PUBLISHING HOUSE

Subject/Index Terms

• TRT Terms: Accuracy; Clay; Conferences; Consolidation; Creep; Evaluation and assessment; Instruments for measuring loads or pressure; Kaolinite; Pressiometric probes; Shear strength; Soil stabilization; Strength of materials; Swelling soils
• Uncontrolled Terms: Pressiometer
• Subject Areas: Geotechnology;

Filing Info

• Accession Number: 00607145
• 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