STP740: Comparison of Shear Strength Values Derived from Laboratory Triaxial, Borehole Shear, and Cone Penetration Tests

    Lambrechts, JR
    Staff engineer and vice president, Haley & Aldrich, Inc., Cambridge, Mass.

    Rixner, JJ
    Staff engineer and vice president, Haley & Aldrich, Inc., Cambridge, Mass.

    Pages: 15    Published: Jan 1981


    Abstract

    To determine the shear strength of two different soils, in situ and laboratory tests were performed and the results compared. The soil shear strength parameters were required to evaluate the cause of movements of a steel sheet pile cofferdam in which piles were being driven for a bridge pier. Two in situ techniques, the Quasi-Static Cone Penetration Test and the Borehole Shear Test, and laboratory CIU triaxial compression tests were used to determine the drained shear strength parameters (¯c and ¯φ) of silt and varved silt soils. Shear strength parameters derived from all three procedures were in close agreement. The angle of internal friction of the varved silt ranged from 28 to 33 deg, and the range for the silt was 32 to 36 deg. Soil densification during sampling and sample transportation is thought to have slightly increased ¯φ-values from the CIU tests. Based on field observations, slope inclinometer measurements, and tension crack occurrence around the land-side of the cofferdam, it was concluded that a “classical” active earth pressure wedge acted against the land-side of the cofferdam. An overall equivalent ¯φ, ranging from 26 to 34 deg, was derived from the location of this wedge.

    Keywords:

    varved silt, silt, shear strength, angle of internal friction, borehole shear test, cone penetrometer test, triaxial test, sample disturbance, active earth pressure


    Paper ID: STP28770S

    Committee/Subcommittee: D18.05

    DOI: 10.1520/STP28770S


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