Dynamic response of underreamed batter piles subjected to vertical vibration

ABSTRACT This paper presents the dynamic vertical response of a vertical and two batter piles with an underreamed bulb. Batter angles (i.e. inclination to the vertical) of 10 and 20 degrees have been considered. The dynamic vertical tests were conducted using a mechanical oscillator-motor assembly by varying the intensity of exciting force level with a change in eccentricity setting of the oscillator. The dynamic response was recorded in terms of operating frequency and acceleration response. The test data were analysed to estimate the dynamic vertical responses of the piles in terms of resonant frequency, f y ꞌ; peak vertical displacement amplitude, dyꞌ and axial strain εy , and they were compared. For all three piles, with an increase in intensity of exciting force level, the resonant frequency decreased, whereas the peak vertical displacement and axial strain increased.