| Popis: |
For exploring the attenuation law of limestone dynamic elastic modulus (DEM) under fatigue cyclic loading, 24 limestone specimens were used to conduct dynamic uniaxial cyclic compressive tests under different loading frequencies and stress amplitudes on MTS Test System. The tests results confirmed that the decrease of DEM goes through three different stages with the increase of cyclic numbers. And, there is no distinct correlation between three-stage evolution rule of DEM and frequencies as well as stress amplitudes. The degeneration of DEM is caused by accumulation of micro-cracks and damage increase in rock specimen. Thus, based on attenuation rule of DEM, a fatigue damage evolution model which can depict the first two stages of limestone fatigue damage development was proposed. |
