Vertical Response of 2 × 2 Pile Group Under Rotating Machine Induced Vibrations

Abstract

The dynamic behavior of 2 × 2 pile group has been investigated under rotating machine induced vertical vibration using both field testing and numerical analysis. Forced vibration tests have been performed in the field on a pile group (pile length = 3 m, pile diameter = 0.114 m) embedded in silty soil. The frequency-amplitude responses of the pile group are measured for four different eccentric moments. It is found that the measured response curves are nonlinear in nature. The numerical analysis has been performed using continuum approach and superposition method to determine the nonlinear frequency-amplitude responses of the pile group. From the analysis, the boundary parameters and soil-pile separation lengths are predicted for different eccentric moments. The analytical frequency-amplitude responses of the pile foundations are compared with the dynamic field test results and it is found from the comparison curves that the nonlinear frequency-amplitude responses obtained from the analysis have a very close match with the field nonlinear response curves.