Pile Driving

Abstract

A method of driving a pile or drill stem into the ground using a vibrational driver which is fixedly secured to an upper end of the pile or drill stem to be driven so that vibration of the driver in an elongate direction of the pile is effected to both push and pull the pile in correspondence to the vibrational drivers effort, and driving the pile or drill stem at resonance.

1 . A method of driving a pile or like into the ground, which method includes the steps of:
 securing a vibrational driver to an upper end of the pile to be driven so that vibration of the driver in an elongate direction of the pile is effected to both push and pull the pile in correspondence to the vibrational drivers effort, and the driver is then caused to vibrate at a vibration rate sufficiently high so that the rate of vibration will be for at least some period of the vibration higher than a resonant frequency of the pile in its institu position together with its attached driver, and being sufficiently low so that the rate of vibration will be for at least some period of the vibration lower than a resonant frequency of the pile in its institu position together with its attached driver;   measuring hydraulic fluid drive pressures of the driver;   effecting a raising or lowering vibrational rate in response to detected pressure characteristics indicating whether the vibration rate is above or below resonance; and   effecting a change in the vibrational rate in response to the detected pressures to effect a vibrational rate which is closer to the resonance frequency of the pile in its institu position together with its attached driver.   
     
     
         2 . The method according to  claim 1 , wherein a change in the vibrational rate in response to detected vibrational rate status is effected manually. 
     
     
         3 . The method according to  claim 1 , wherein a change in the vibrational rate in response to detected vibrational rate status is effected by an electrically generated signal which effects a change in the vibration rate. 
     
     
         4 . The method according to  claim 1 , wherein a change in the vibrational rate in response to detected vibrational rate status is effected by reference to a computer algorythm to indicate that the actual vibrational rate is either above or below a resonant vibrational frequency. 
     
     
         5 . An apparatus for driving a pile or drill string into the ground, which apparatus includes:
 a vibrational driver secured to an upper end of the pile or drill string and adapted to be driven so that vibration of the driver in an elongate direction of the pile is effected to both push and pull the pile in correspondence to the vibrational drivers effort, and the driver is then caused to vibrate at a vibration rate sufficiently high so that the rate of vibration will be for at least some period of the vibration higher than a resonant frequency of the pile in its institu position together with its attached driver, and being sufficiently low so that the rate of vibration will be for at least some period of the vibration lower than a resonant frequency of the pile in its institu position together with its attached driver,   means to measure hydraulic fluid drive pressures of the driver, and   means to effect a raising or lowering of the vibrational rate in response to detected pressure characteristics indicating whether the vibration rate is above or below resonance, and effecting a change in the vibrational rate in response to the detected pressures to effect a vibrational rate which is closer to the resonance frequency of the pile in its institu position together with its attached driver.   
     
     
         6 . The apparatus according to  claim 5  in which there are means to effect a control of velocity of hydraulic fluid passing through the driver.