Evaluation of Dynamic Properties of Trackbed Foundation Soil Using Mid-size Resonant Column Test
Yujin Lim, Tien Hue Nguyen, Seong Hyeok Lee and Jin-Wook Lee
International Journal of Railway, vol. 6, no. 3, pp.112-119, 2013
Abstract : A mid-size RC test apparatus (MRCA) equipped with a program is developed that can test samples up to D=10 cm
diameter and H=20 cm height which are larger than usual samples used in practice. Using the developed RC test apparatus,
two types of crushed trackbed foundation materials were tested in order to get the shear modulus reduction curves
of the materials with changing of shear strain levels. For comparison purpose, large repetitive triaxial compression tests
(LRT) with samples of height H=60cm and diameter D=30 cm were performed also. Resilient modulus obtained from
the LRT was converted to shear modulus by considering elastic theory and strain level conversion and were compared to
shear modulus values from the MRCA. It is found from this study that the MRCA can be used to test the trackbed foundation
materials properly. It is found also that strain levels of Ev2 mostly used in the field should be verified considering
the shear modulus reduction curves and proper values of Ev2 of trackbed foundation must be used considering the strain
level verified.
Keyword : mid-size resonant column test, shear modulus, trackbed foundation materials, large repetitive load test, Ev2 |