ISSN: 1945-7545
CODEN: GTJODJ
Published Online: 7 September 2010
Page Count: 11

A Shear Wave Velocity Tomography System for Geotechnical Centrifuge Testing

Kim, Nam-Ryong
Postdoctoral Researcher, Former Ph.D. student, Dept. of Civil and Environmental Engineering, KAIST, Daejeon,

Kim, Dong-Soo
Professor, Dept. of Civil and Environmental Engineering, KAIST, Daejeon,

(Received 26 November 2009; accepted 30 July 2010)

Abstract

In physical model tests using geotechnical centrifuge, it is important to evaluate soil properties during centrifugal acceleration due to the effect of stress conditions. A crosshole type shear wave velocity tomography testing system has been developed, and the distribution of maximum shear modulus in sand layers could be evaluated in the centrifuge. Piezoelectric bender elements are installed in the system as shear wave transmitters and receivers for travel time measurement. A driving and measurement system for bender element tests is prepared to be used under centrifuge operating environment. A series of tests using this system has been conducted with uniform sand samples, and the testing procedure and typical signals from bender elements are presented. Tomography inversion considering curved raypaths has been conducted using a total of 256 travel time data determined by measured signals because the first arrivals follow curved raypaths under a stress related linear variation in stiffness with depth. The maximum shear modulus variation with depth, or vertical effective stress, has been verified through comparison with resonant column test results, and the applicability of this system in general centrifuge testing has been confirmed.

Keywords:
physical modeling, geotechnical centrifuge, bender element, shear wave velocity

Paper ID: GTJ102894
DOI: 10.1520/GTJ102894
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