A New Free-Free Resonant Column Device for Measurement of G_max and D_min at Higher Confining Stresses
Kalinski, ME
Department of Civil Engineering, University of Kentucky, Lexington, KY

R. Thummaluru, MS
Alexcom and Associates, Fredricksburg, VA

(Received 8 August 2003; accepted 13 August 2004)

Abstract
The fixed-free resonant column device has traditionally been used to measure shear modulus in laboratory soil and rock specimens. It is a proven method that provides measurements over a range of shear strain and effective confining stress (s¢_o), but the test relies on a specialized system of coils and magnets. The free-free resonant column device is a simpler device that allows for measurement of small-strain shear modulus (G_max) and small-strain material damping (D_min). However, s¢_o in the free-free device has traditionally been limited to a maximum attainable vacuum pressure of around 80 kPa, because the test has not been configured in a pressurized cell. Therefore, a new free-free device was developed to allow measurements in a pressurized cell with s¢_o greater than 80 kPa, while remotely exciting the specimen with a rotary solenoid. Test results demonstrate its potential for measuring G_max and D_min under higher levels of s¢_o that are more representative of in situ conditions.

Keywords:
confining stress, resonant column, shear wave velocity, small-strain material damping, small-strain shear modulus, soil, soil dynamics

Paper ID: GTJ12187
DOI: 10.1520/GTJ12187

ASTM International is a member of CrossRef.
Author Kalinski, ME Affiliation Department of Civil Engineering, University of Kentucky, Lexington, KY Author R. Thummaluru, MS Affiliation Alexcom and Associates, Fredricksburg, VA Author Kalinski ME, R. Thummaluru MS Title A New Free-Free Resonant Column Device for Measurement of G_max and D_min at Higher Confining Stresses Symposium , Committee on