Sonic drill

How does it work?

Sonic drilling is a soil penetration technique that strongly reduces friction on the drill string and drill bit due to liquefaction, inertia effects and a temporary reduction of porosity of the soil. 

Liquefaction

When you use a sonic drill head, the entire drill string is brought to a vibration frequency of up to
150 Hz. This causes a very thin layer of soil particles directly surrounding the drill string and bit to loose structure. Instead of a stiff mass, the soil behaves like a fluid powder or paste. This fluidization, or liquefaction, dramatically reduces friction.

Inertia

In addition to the liquefaction the soil simply is not able to stick to the drill string, because it is moving up and down some 150 times per second.

Compaction

The vibrations of the drill bit cause the soil to loose structure, changing it to a higher density with a lower porosity. This way the soil opens up for the drill string to advance. When you retrieve the drill string after drilling, the suction and some vibration will cause the soil to regain much of its old lower density, and water will be able to flow freely again.

The effect

The liquefaction and inertia effects enable you to collect very long and continuous samples. Due to the vertical high-frequency movement the drill string stays extremely straight, with a diversion of no more than a few centimeters over the full length of the bore hole. In alluvial material, vertical vibrations are generally enough to drive down a drill string for many meters without the injection of any water or air.

When you are drilling in hard formations, liquefaction cannot take place. In such cases you can combine vibration with rotation, and use rock drill bits to cut the material. In order to keep the temperature of the drill bit down and lift the cuttings, foam injection is the best solution, but you can use water or air as well.

Please refer to SonicSamp web site is here for further information. You can also call AFRASIA to talk about your drilling needs using sonic drill.

Sonic Drill images

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