Double rotary drilling
A single-pass drilling method
Cased continuous flight auger drilling (CCFA)
Double rotary drilling combines continuous flight auger drilling with a continuous casing. Casing and auger (inside the casing) are simultaneously installed and extracted. Double rotary drilling is applied for the production of cast-in-place piles and for predrilling.
Procedure of producing a cast-in-place concrete pile with double rotary drilling:
1. Positioning at the drilling point
2. Auger drilling with simultaneous advance of the casing
3. Extraction of auger and casing while concrete is pumped in through hollow stern
4. Inserting the reinforcement
5. Finished pile
Video double rotary drilling
The video shows two jobsites with double rotary drilling for producing cast-in-place piles.
This YouTube video is provided by Google*. If you load the video, your data - including your IP address - is transmitted to Google and may be stored and processed by Google inter alia in the USA. We have no influence over further data processing by Google.By clicking on "Accept", you consent to the transmission of data to Google for this video in accordance with Art. 6 (1) (a) GDPR and at the same time explicitly consent to the transfer of data to the USA in accordance with Art. 49 (1) (a) GDPR. If you no longer wish to consent to each YouTube video individually in the future and wish to be able to load the videos without this blocker, you can also select "Always accept YouTube videos" and thereby consent to the associated data transmissions and transfers to Google and to the USA for all other YouTube videos which you open on our website in the future. Please note that, in the opinion of the European Court of Justice, there does not currently exist an adequate level of data protection in line with EU standards in the USA, and at present we cannot provide appropriate safeguards to protect your data and offset this shortcoming.Possible risks to you of data transfer to the USA are that access by state authorities cannot be excluded and that your data could be processed for reasons of national security, law enforcement or for other purposes in the public interest of the USA, possibly without you being informed separately and without enforceable rights and effective legal remedies being available to you.You can withdraw consent that you have given at any time with future effect via the settings. For further information, please see our Data Protection Declaration and Google's Privacy Policy.*Google Ireland Limited, Gordon House, Barrow Street, Dublin 4, Ireland; parent company: Google LLC, 1600 Amphitheatre Parkway, Mountain View, CA 94043, USA
Combination of continuous flight auger and casing
This method combines continuous flight auger drilling with a casing. It is mainly applied for producing cast-in-place piles.
Double rotary drilling
Two rotary drives are separately mounted on the sledge and independently drive the inner continuous flight auger and the casing.
Installing cast-in-place piles
During the drilling process the auger flights convey the drill cuttings to the surface inside the casing. Through an opening at the upper end of the auger the drill cuttings are ejected.
âFront-of-wallâ drilling
The compact design of the double rotary head allows operation very close to existing building structures, i.e. in front of building walls.
Protection cover
A protection cover encloses the casing so creating an annular space inside. Thus, the ejected drill cuttings fall to the ground in a controlled manner.
Emptying the auger
After their extraction, casing and auger are swung to the side and emptied by rotating the auger in the reverse direction.
Extracting and concreting
After the final depth has been reached concrete is pumped through the augerâs hollow stem. During the extraction process the concrete exits at the lower end of casing and auger.
Reinforcement
After concreting a reinforcement cage can be inserted in the column of fresh concrete. For this purpose the auxiliary winch of the carrier machine is used.