Rocking Field Response of Combined Soil-Pile Systems Under Machine-Based Dynamic Conditions

Rocking excitations generally occur in machines that are mounted on high pedestals and have unbalanced horizontal forces and exciting moments about longitudinal direction. This type of excitation mode is critical when it is under nonlinear dynamic conditions and is often considered when designing machine-based pile foundations. Therefore, in the present work, in-situ tests are conducted on six piles with different loading directions to investigate the impact of dynamic pile-soil-pile interaction under machine-produced vibrations. The small-scale model steel pipes are used to determine the dynamic rocking responses of two distinct sets (2 × 3 and 3 × 2–pile groups) of pile groups at various eccentric moments. Two resonant peaks can be seen in the measured response curves during field testing within the produced frequency range of the DC motor. The dynamic responses are measured in terms of frequencies and amplitudes for both sets, and it is observed that the 3 × 2–pile groups measured lower values of resonant frequencies and higher values of resonant amplitude as compared to the 2 × 3–pile group considering all eccentric forces. It demonstrates that the influence of pile and soil interaction is more significant for 3 × 2 than for 2 × 3 loading conditions.