Mechanical knowledge base: Vibratory sinker

The vibratory pile driver consists of a vibratory pile hammer and a universal pile frame. Vibratory pile hammers use mechanical vibration to sink or extract piles. According to the vibration frequency, it can be divided into four types: low, medium, high and ultra-high frequency; according to the principle of action, it can be divided into two types: vibrating type and vibration type; according to the connection between power device and vibrator, it can be divided into rigid type and soft type. Species. According to the power 1 source is divided into electric and hydraulic two.

1) Working Principle of Vibration Pile Hammer

The main device of the vibration pile hammer is a vibrator, which uses the exciting force generated by the vibrator to generate high-frequency vibration of the pile body. At this time, the pile sinks into the soil under the effect of its own weight or a small additional pressure, or pulls out the soil under the effect of a small lifting force.

The method for generating the exciting force of the vibrator is as follows: The vibrators use a mechanical vibrator and are composed of two shafts equipped with eccentric blocks (as shown in the figure). The same eccentric block is mounted on the two shafts, but the two shafts rotate toward each other. This is the centrifugal force generated by the eccentric blocks on the two shafts. The horizontal component forces cancel each other out, and the vertical component forces are superimposed.

2) Electric vibration sinker

The electric vibratory sinker/puller is a vibration produced by a vibrator, and is transmitted to the pile body through a pile clamp integrated with the vibrator, so that the pile body vibrates. The soil around the pile is subjected to vibration and the frictional resistance is significantly reduced. The pile sinks into the soil under the action of a vibratory piling machine and its own weight. When pulling the pile, vibration can significantly reduce the resistance of the pile, and only a small lifting force can pull the pile out.

The electric vibrating pile extractor consists of a vibrator, a pile holder, and an electric motor. The rigid connection of the motor 2 to the vibrator 1 is called a rigid vibratory hammer (as shown). A coil spring installed between the motor 4 and the vibrator 1 is called a flexible vibratory hammer.

The eccentric block of the vibrator can be driven by the motor with a triangular tape, and the vibration frequency can be adjusted so as to adapt to the different requirements on the excitation force without playing different piles on the soil.

Pile holders are used to connect pile hammers. Separate hydraulic, pneumatic, manual (lever or hydraulic) and direct (pin or cone) and so on.

The figure shows a vibro-impact vibration pile hammer. It sinks by vibration and by impact. The vibrator and the impact plate are connected via springs. When the two eccentric blocks are driven by the motor and synchronously rotate in the opposite direction, the vibrator 1 is vibrated in the vertical direction, and the impact bump is given a series of quick impacts to quickly sink the pile.

This vibro-impact pile hammer has great amplitude and impact force, and its power consumption is also low, and it is suitable for piling on viscous soil or hard soil. The disadvantage is that the noise during impact is large and the motor is vulnerable to frequent impacts.

3) Hydraulic vibration sinker

The hydraulic motor is driven by the hydraulic motor. The hydraulic motor drive can steplessly adjust the vibration frequency, as well as the advantages of small starting torque, small size, light weight, and no power supply. However, its transmission efficiency is low, the structure is complex, maintenance is difficult, and the price is high.