Experimental study on the disturbance characteristics of saturated sand under radial vibration excitation
To investigate the disturbance effect of radial vibration excitation on saturated sand,the vibration test system with radial excitation capability and adjustable frequency was developed.Disturbance tests on saturated sand were conducted using this system under vibration frequencies ranging from 10 to 50 Hz.The spatiotemporal evolution and distribution characteristics of the disturbance effect induced by radial vibration excitation were analyzed.The results indicated that,within the scope of the test conditions,the pore water pressure at each measurement point initially increased,and after reaching its peak,gradually decreased and stabilized under vibration excitation.It was observed that as the vibration frequency increased,the degree of disturbance to the saturated sand became more severe,with a gradual increase in excess pore water pressure,excess pore pressure ratio,liquefaction duration,and vibration acceleration at each measurement point.At the vibration frequency of 30 Hz,some measurement points reached liquefaction state,while at 40 Hz and 50 Hz,all measurement points entered liquefaction state.Moreover,as the depth increased,the pore pressure at each measurement point during vibration was higher,the peak was reached earlier,and the liquefaction duration was shorter.The soil near the middle of the vibrator experienced the most severe disturbance,with measurement points in this location entering liquefaction state earliest,and the amplitude of pore pressure oscillation,relative oscillation amplitude,and peak excess pore pressure ratio were all higher at these measurement points compared to those at both ends of the soil.Additionally,the closer the measurement points were to the vibration center along the radial direction,the greater the vibration acceleration,the higher the maximum excess pore pressure ratio,the earlier the entry into liquefaction state,and the longer the duration of liquefaction.These findings provide guidance for selecting grouting timing,setting grouting outlet positions,and choosing vibration parameters,laying a foundation for further research on radial vibration grouting tests.
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