Subsidence of Sand due to Surface Vibration

Laboratory tests were conducted using a plate-type vibrator on the surface of a sand sample. The static weight, dynamic force, and frequency of the vibrator were independently varied and the resulting contact force, acceleration, amplitude of vibration, and residual settlement were measured. Results showed that the parameter that governs the surface settlement of a vibrating footing on a granular mass is the steady-state transmitted energy. This is true for a wide range of frequencies both above and below resonance and for large variations in the ratio of the dynamic force to static weight, provided this ratio is less than unity and the total transmitted force does not exceed the static failure load. It was demonstrated that, in general, the surface settlement cannot be correlated to acceleration only. The transmitted energy may also be a key factor in the design of efficient vibratory compaction equipment.