Evaluation of the Stiffness of a Synthetic Soft Rock using Bender Elements

Significant strength and stiffness come from the intact structure of soft rock, however, conventional drilling, sampling and extraction disturbs the material structure and results in a under representation of measured parameters. Non-destructive wave-based methods instead preserve the material structure, but the stiffness is measured at smaller strains than typically encountered in geotechnical applications. Experiments were conducted on a synthetic hard soil/ soft rock at different moisture contents using bender elements and compared to conventional unconfined compressive testing. Design curves were developed that allows a stiffness measured using bender element wave based methods to be scaled to any other intermediate strain.