Drehbohren

Rotary drilling

Rotary drilling

The drilling system rotates as it is sunk into the geology. Depending on the hardness of the foundation soil and the framework conditions involved, a distinction is made among the various drill bits (rotary bit/roller bit) and the type of uplift/transport used for the drill cuttings (auger/flushing).

Unlike rotary percussive drilling, pure rotary drilling is non-percussive. In this case, the soil is loosened solely through the cutting forces of rotation and contact pressure.

Uplift can be provided via auger, a continuous flight auger, for instance.

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With hard rock formations, the roller bit offers an alternative to creating a borehole. Here, the roller bit uses the high point loads produced by the contact pressure of the feed to break the rock. Drill cuttings are extracted using a flushing medium, e.g. water or air, that is introduced through the drill pipes. This discharges the loosened drill cuttings at the mouth of the borehole through the annular gap between drill pipes and borehole wall.