Time-Dependent Triaxial Relaxation Behavior of a Resedimented Clay

    Volume 17, Issue 4 (December 1994)

    ISSN: 0149-6115

    CODEN: GTJOAD

    Page Count: 9


    Sheahan, TC
    Assistant professor, Northeastern University, Boston, MA

    Ladd, CC
    Professor, Massachusetts Institute of Technology, Cambridge, MA

    Germaine, JT
    Principal research associate, Massachusetts Institute of Technology, Cambridge, MA

    Abstract

    The paper describes the results of K0 consolidated-undrained triaxial compression relaxation tests on resedimented Boston Blue Clay (BBC) using a computer-automated triaxial apparatus. Specimens were either normally consolidated (overconsolidation ratio, OCR = 1) or had an OCR = 4, and they were sheared at different axial strain rates to axial strains (εa) from 0.1 to 15%. Each strain level was maintained until the monitored shear stress and pore pressure reached equilibrium levels. The results show that a single specimen can be used reliably for multiple relaxation tests. During relaxation, the rate of normalized shear stress decay with log time, (−Δq/σ′vm)/Δlogt, is approximately constant, regardless of εa or OCR. Changes in shear-induced pore pressure during relaxation were negligible except when specimens were rapidly sheared. Independent of OCR, end-of-relaxation equilibrium stress states for relaxation strains εa ≤ 1.5% lie on a line of obliquity defined by K = σ′h/σ′v = 0.50, compared to K0 = 0.49 for OCR = 1 BBC; whereas, for εa ≥ 2.5%, the equilibrium states lie on a steeper obliquity line defined by K = 0.40.


    Paper ID: GTJ10305J

    DOI: 10.1520/GTJ10305J

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    Author
    Title Time-Dependent Triaxial Relaxation Behavior of a Resedimented Clay
    Symposium , 0000-00-00
    Committee D18