• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.3C
• /
• pp.103-108
• /
• 2011

In this study, the limitations of large strain resonant column and torsional shear tests apparatus are described and solutions to the limitations are also described. The limitations are rotational distance, limited torque, and measurable deformation system, respectively. To resolve the rotational distance, the bottom platen was modified. And the four-armed drive plate was modified into eight-armed drive plate and the drive coil connection was changed to obtain powerful torque.

• International Journal of Highway Engineering
• /
• v.10 no.3
• /
• pp.1-10
• /
• 2008

Conventional RC/TS(resonant column and torsional shear) device usesa specimen with an aspect ratio(height-to-diameter) of 2:1 and this generates a maximum shear strain in the sample of about 1.5% at the maximum rotation of the drives system. The objective of this study is to modify RC/TS device to generate higher strain amplitude. The modifications include a new base pedestal to overcome the limitations in the travel of the drive system and modification of coil wiring to increase torque. The effects of the new coil wire on torque in the electro magnetic drive system were evaluated and the application of modified device was illustrated using sand soil.

• Journal of the Korean Geosynthetics Society
• /
• v.10 no.2
• /
• pp.21-28
• /
• 2011

Several theoretical soil nonlinear models to predict damping ratio, which is one of the typical dynamic properties of soils, it is impractical to predict damping ratio. The resonant column and torsional shear test(RC-TS) is used to represent the dynamic behavior of soils from intermediate to medium shear strains. A limitation of RC-TS is measure precise shear strain in large strains and the modified equivalent radius($R_{eq}$) was obtained using both modified hyperbolic model and Ramberg-Osgood model. Bonneville clays were tested using RC-TS test to obtain rotation and torque. The measured rotation and torque were then compared with calculated rotation and torque using curve-fitting method. Then, the nonlinear soil model parameters were obtained and the equivalent radius was calculated using the model parameters.