Uniaxial Strain Testing of Soils in a Split Hopkinson Pressure Bar

摘要

The split-Hopkinson pressure bar (SHPB) technique has been adapted to measure the dynamic response of soil to impulse loads. The experimental technique is relatively simple and can investigate soil response in regimes beyond the capabilities of current equipment used for soil dynamic laboratory investigations. Soils have several characteristics which must be considered in designing a SHPB experiment and evaluating the data (e.g., low wave speeds, nonlinear hysteretic behavior, and low unconfined compressive strength compared to the applied loads). Insight has been gained as to how these factors affect experimental accuracy and data reliability. The ability to replicate experimental results has been established. Also, the stress-strain response was found to be governed by the initial gas porosity of the specimen. No strain-rate dependence was found at strains less than the initial gas porosity. To model the response of dry desert alluvium, a microphysical constitutive equation has been devised. 20 refs., 19 figs. (ERA citation 11:021148)