Volume 31, Issue 1 (January 2008)

    Effects of Specimen Size and Some Other Factors on the Strength and Deformation of Granular Soil in Direct Shear Tests

    (Received 23 August 2006; accepted 23 May 2007)

    Published Online: 2007

    CODEN: GTJOAD

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    Abstract

    Four direct shear (DS) apparatuses having different sizes with the specimen lengths ranging from 40 to 800 mm were constructed in the study. The vertical and shear stresses acting on the shear zone were measured as accurately as possible confirming its importance. Noticeable effects of specimen shape were observed. The effects of specimen size were evaluated by performing constant pressure DS tests on a fine poorly graded sand (Toyoura sand) in the small, semimedium, medium and large DS apparatuses and a well-graded sandy gravel in the medium DS apparatus. The residual shear strength of Toyoura sand was independent of the specimen size and initial density. Due likely to specimen size effects on both progressive failure and boundary mechanical restraint, the peak strength decreased with an increase in the specimen size. As the specimen size increased with dense Toyoura sand and as the particle size increased in the medium DS tests, the shear displacement at the peak stress and the ultimate volume increase at the residual state consistently increased while the postpeak strain softening became slower. These specimen size effects can be attributed to the thickness of shear zone and the number of shear bands included in the shear zone.


    Author Information:

    Wu, Po-Kai
    Assistant Professor, Department of Construction Engineering, National Yunlin University of Science and Technology, Yunlin,

    Matsushima, Kenichi
    Research Engineer, National Research Institute of Rural Engineering, Tsukuba City, Ibaraki

    Tatsuoka, Fumio
    Professor, Department of Civil Engineering, Tokyo University of Science, Noda City, Chiba


    Stock #: GTJ100773

    ISSN: 0149-6115

    DOI: 10.1520/GTJ100773

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    Author
    Title Effects of Specimen Size and Some Other Factors on the Strength and Deformation of Granular Soil in Direct Shear Tests
    Symposium , 0000-00-00
    Committee D18