EFFECT OF A TRACKED VEHICLE MOUNTING AN OSCILLATOR ON THE VIBRO-COMPACTION OF A HIGH LIFTED DECOMPOSED GRANITE SANDY SOIL

抄録

The objective of this paper is to develop a new vibro-compaction machine by investigating experimentally the effects of the frequency of an oscillator mounted on a tracked vehicle on the vibro-compaction of a high lifted decomposed granite sandy soil. By measuring the amount of depression of the ground surface, the dry density distribution in depth using a cone penetrometer, the normal earth pressure distribution in depth using a soil stress transducer, and the vertical and horizontal acceleration distribution in depth, the effects of the tracked vehicle on the increment of the soil compacting dry density in a deep stratum were considered theoretically for various kinds of frequency. It was observed that an oscillator frequency of 16 Hz with a constant amplitude of exciting force of 9.8 kN showed the maximum amount of depression of the ground surface and the maximum dry density distribution at deep stratum for the range of frequency from 16 Hz to 51 Hz. The ratio of dynamic shear stress to normal stress at 16 Hz proved to be large enough at deep stratum, so that an optimal alternative shear strain due to the impact force was developed on the whole range of the high lifted stratum. It was assumed that the increment in soil compacting density was the result of the effective dilatancy phenomenon.