| Popis: |
A DETAILED STUDY HAS BEEN MADE OF THE FACTORS CONTRIBUTING TO DENSIFICATION OF DRY SAND ON A SHAKING TABLE. THE VARIABLES CONSIDERED WERE THE FREQUENCY OF VIBRATIONS, AMPLITUDE OF VIBRATIONS, AND SIZE AND SHAPE OF CONTAINER. NO SURCHARGE WAS USED IN ANY TEST. THE DIFFERENT PROCESSES AFFECTING THE ACHIEVED DENSITY WERE FOUND TO BE: (1) REPEATED CHANGE IN VERTICAL STRESS OWING TO INERTIA FORCES WITHIN THE SAND WHEN THE PEAK ACCELERATION IS LESS THAN 1 G (2) REARRANGEMENT OF PARTICLES DURING FREE FALL, WHEN THE PEAK ACCELERATION JUST REACHES 1 G (3) IMPACT ACTION AT THE END OF FREE FALL, WHEN THE PEAK ACCELERATION EXCEEDS 1 G AND (4) SPALLING OF THE SURFACE LAYER BY STRESS WAVE REFLECTIONS, WHEN THE PEAK ACCELERATIONS REACH SEVERAL G'S. /AUTHOR/ |
