ANCHORS (geotechnical anchors)
TECHNOLOGY OF CONSTRUCTION OF ACTIVE GEOTECHNICAL ANCHORS
Active anchors are used to tighten and hold the protective structure. Work on the execution of designed anchors takes place in the following phases:
Drilling of holes for anchors is done by using the appropriate equipment for rotary drilling with the appropriate diameter and at the designed angle. If the bore hole collapses during drilling, the hole should be cased with pipes of larger diameter.
If the drilling equipment deteriorates or water is lost during drilling, it should be injected and cleaned after the grout has hardened.
The active anchor is formed from the required number of ropes with a diameter of 16 mm (nominal strength fpk = 1770N / mm2).
The anchor zone is performed “wavy” with the help of steel inner distributors and outer rings mounted on each long meter. The anchor part prepared in this way is mounted in a perforated pipe with a diameter of 86/80 mm. A protective cap is installed at the very end of this pipe. The free part of the anchor is installed in a protective tube made of polyethylene material with a diameter of 90/78 mm.
For concreting the anchor zone of the anchor through the anchor shaft, a plastic hose with a diameter of 25/19 mm is mounted.
After the injection of the anchor part outside the well, the anchor is inserted into the well, after which the secondary injection of the anchor zone is performed. Finally, the anchor free length are also injected with the injection mass.
During installing anchors, it is obligatory to keep a record of each individual anchor. This record must contain the place and time of installation of the anchor, the type and condition of the material through which the anchor passes, the depth of the well, the type of anchor, the test result, ie the entered prestressing force and the signatures of the contractor and supervisor.