Vertical vibration of piles with square cross-section

The paper presents an approximate solution to axial dynamic impedance calculation for group of square piles. Firstly, dynamic responses of the single pile-soil system are derived on the basis of Hamilton's energy principle and variation analysis. Then, the effects of square cross section on the pile-soil interaction are examined through the combination of theoretical deduction and numerical simulation. The vertical soil vibration around a square pile is found to be dependent on wave propagation directions in the near field (two times less than the side length of square pile). As the radial distance off pile axis increases, the soil vibration tends to be independent on propagation directions. Through superposition principle, the dynamic impedance of square pile group is calculated. This study could provide a reference to the problems with how the non-circular piles interplay with soil on vibration.