Functional Principle

The Vibrodriver vibrates profiles, sheet piles or casings to drive or extract in vertical vibrations. This in turn causes the adjacent ground to shift. The ground is loosened, which leads to the pile being driven into the ground by its own and the vibrator's weight. It can be extracted by the same principle via the pulling force of the carrier (crane) in use.

Design

The vibrodriver is shifted in unidirectional vertical vibrations through the eccentrics mounted in the gearbox. The eccentrics, ordered in pairs, turn with the same angular velocity in opposite directions.

Both eccentrics generate centrifugal forces fc. The horizontal components fh are offset at the same time that the vertical components fv are added resulting in a centrifugal force Fc.

Selection

The selection of a vibrodriver is based on:
 
•  cross section of pile
•  ram profile weight
•  penetration
•  soil layer consistency
•  soil porosity

The diagram, which has been derived from experience, can be used to preselect the vibrodriver.

Moreover, driving efficiency can be improved by air or water jetting.

Parameters

 is the product of the mass (m) of the eccentric and the distance (r) between its centre of gravity and its rotational axis. The eccentric moment of the vibrodriver is equal to the sum of the moments of the eccentrics:

Each eccentric generates a centrifugal force:

 is the total vertical displacement of the vibrating elements during one complete revolution of the eccentrics. The maximum amplitude is achieved using the formula:


                     
 This is the sum of the weights of the vibrating gearbox, the clamping head and the element to be driver or extracted.