ISSN: 1945-7545
CODEN: GTJODJ
Published Online: 23 October 2007
Page Count: 10

Effect of Specimen Size on Quasi-Elastic Properties of Toyoura Sand in Hollow Cylinder Triaxial and Torsional Shear Tests

HongNam, Nguyen
LecturerGraduate Student, Division of Geotechnical Engineering, Hanoi Water Resources UniversityDepartment of Civil Engineering, The University of Tokyo, Dong Da District, Hanoi

Koseki, Junichi
Professor, Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo

Sato, Takeshi
Research Support Promotion Member, Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo

(Received 8 July 2005; accepted 11 September 2007)

Abstract

Quasi-elastic deformation properties of dry, dense Toyoura sand were experimentally investigated by triaxial and torsional shear tests on hollow cylindrical specimens of medium sizes (outer diameter D_o=20 cm, inner diameter D_i=16 or, 12 cm, and height H=30 cm) and small size (D_o=10, D_i=6, H=20 cm). In addition to the conventional external measurements, strains were measured locally by the newly developed pin-type local deformation transducers. The effect of specimen size on locally measured Young’s modulus E_z was insignificant. On the other hand, the locally measured values of shear modulus G_zθ with the small size specimen revealed lower reproducibility as compared with those measured with the medium size specimens, suggesting that larger specimen size is preferred in evaluating the small strain shear modulus in torsional shear tests on hollow cylindrical specimens. It was also inferred from the test results that, irrespective of the specimen size, effect of end restraint at the top cap and pedestal is significant on the externally measured values of G_zθ.

Keywords:
hollow cylinder apparatus, sand, elasticity, anisotropy, shear modulus, Young’s modulus, Poisson’s ratio

Paper ID: GTJ100022
DOI: 10.1520/GTJ100022
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