MEASUREMENTS OF EFFECTIVE STRENGTH PARAMETERS OF STIFF FISSURED CLAYS USING LARGE IN SITU SHEAR BOXES . 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 describes the measurement of strength parameters of 3 stiff fissured clays using large in situ shear boxes. Tests were carried out both in Barton clay at Fawley, Hampshire, in blue London clay at Wandsworth, during the construction of an underpass, and in a highly dessicated marsh clay of flood defence banks. In each test, a 610 mm shear box was used. In the last two tests, where the strength parameters of clays relevant to stability analyses of retaining walls during construction were required, the installation procedures and test procedures were the same, and these are described in detail. The shear stress displacement curves and plots of peak and post peak shear stress value against vertical stress are presented for each site. The results show that large in situ shear box tests are sufficiently large to incorporate a representative selection and number of discontinuities present in the clay. Variations in the measured peak strengths provide a reasonable measure of the variability of the mass properties of the clays and it is appropriate to use mean values. Disturbance of the clay prior to shearing was minimal in the case of the highly dessicated clay. It was possible to evaluate the strength of clays which could not be satisfactorily sampled. An important finding is the consistently low cohesion intercepts and the higher friction angles applicable at low normal stresses which are relevant in many practical problems. Other findings indicate that at low effective stresses, fissured clay may behave like interlocking gravel. 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:
  • Marsland, A
• Publication Date: 1990

Language

• English

Media Info

• Pagination: p. 217-228
• Serial:
  • Publication of: GEOLOGICAL SOCIETY PUBLISHING HOUSE
  • Publisher: GEOLOGICAL SOCIETY PUBLISHING HOUSE

Subject/Index Terms

• TRT Terms: Accuracy; Clay; Conferences; Cracking; Design; Dislocation (Geology); Evaluation and assessment; Rock jointing; Strength of materials; Stresses
• Uncontrolled Terms: Shear box
• Subject Areas: Design;

Filing Info

• Accession Number: 00607163
• 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