During resonant column and torsional shear tests using a Stokoe device, conventionally only the change in height of the specimen is measured. To obtain the change in diameter of the specimen, a relationship between radial strain and longitudinal strain is assumed. In this study, the Stokoe device was modified to enable the measurement of change in diameter of the specimen along with the change in its height during resonant column and torsional shear tests. The diameter change measurement system comprises three proximity probes, coaxial cables, proximitor conditioners, and DC power supply. The probes (7.9 mm diameter) are capable of making noncontact displacement measurements with a resolution of 0.025 mm using a metallic target. These probes are fixed along the circumference of the outer chamber at equal 120 degree spacing. The vertical location of these probes is such that they correspond to the midheight of the specimen. Each probe is mounted on a micrometer to enable accurate adjustment of the probe. This system gives a linear output for a distance range of 0.38 to 2 mm between the probe tip and the metallic target. During the tests, the targets (circular copper foils 26 mm in diameter) are fixed on the soil specimen, and output voltage from each of the three proximity probes is recorded directly by a computer. The average readings of the three probes are used to calculate the change in diameter of the specimen. This paper will present the results of tests on seven residual soil specimens.


    Access

    Download

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Radial Strain Measurements in Resonant Column and Torsional Shear Tests


    Additional title:

    Transportation Research Record: Journal of the Transportation Research Board


    Contributors:


    Publication date :

    1996-01-01




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English




    Radial Strain Measurements in Resonant Column and Torsional Shear Tests

    Gupta, Ayushman / Shao, Lisheng / Borden, Roy | Transportation Research Record | 1996


    Torsional tests on microstructures: two methods to determine shear-moduli

    Schiltges, G. / Gsell, D. / Dual, J. | British Library Online Contents | 1998


    A Modified approach for calculating dynamic shear modulus of stiff specimens by resonant column tests

    Xiaoming, Y. / Jing, S. / Rui, S. | British Library Online Contents | 2006


    Experimental study of torsional column failures

    Niles, A.S. | Engineering Index Backfile | 1939