Analysis on Compressive Stress Signals from Vibrating Compaction on Loess

To discover the vibrating compaction mechanism and optimize the working parameters during vibrating compaction,the compressive stress and the compaction energy on the loess were studied.The distribution of the compressive stress on each layer in the loess was analyzed according to the stress signals in time domain.And the distribution,absorption and transfer of the compaction energy in the loess were analyzed based on frequency spectrum of the compressive stress signals.The results show that(1) The value of the compressive stress on each layer in the loess increases with the increasing of the rolling times and decreases with the increasing of the depth.(2) The compressive stress at the top layer increases most quickly and arrives at its maximum value at the ninth rolling time,the middle and bottom layers both arrive at their maximum values at the eleventh rolling time.(3) The natural frequency of the tested loess is 30 Hz.At this vibratory frequency the compaction effect is the best.(4) The vibratory energy absorbed by each layer decreases with the increasing of the soil density.The top layer can get more energy than the middle and the bottom layers and arrives at the density state firstly.The analysis is in accordance with the experimental result of the compactness.