August 25, 2022
How to Construct the Slope Anchor Cable?
Anchor Cable Making
The anchor cable adopts a 1x7 standard steel strand with a nominal diameter of φ15.2mm and its standard strength is 1860Mpa according to the design requirements. When the anchor cable is made, the length of the steel strand is: anchor section + free section + 1.5m exposed tension section. The steel strand is cut by a toothless saw, and the anchor cable body guiding cone, expansion ring and positioning piece materials are made of φ45mm steel pipe and φ8mm steel bar welding. The anchor cable can be prepared on-site while drilling. The inner anchorage section adopts a corrugated shape and the tensioning section adopts a straight shape.
The free section of the anchor cable should be coated with strong anti-corrosion coating, and the anchor cable bundle should be tied with fine wire every 1m, painted with anti-rust oil, covered with bellows, filled with grease, closed at both ends, and closed and fixed with engineering tape; or each single steel strand should be covered with a φ20-22mm PVC plastic protection tube, filled with grease at both ends within 10-20cm, and closed and fixed with engineering tape. grease closed, and fixed with engineering tape. Anchor cable anchorage ends every 1.0m set a centering bracket (expansion ring), with thickness 20mm polyethylene plastic plate processing, every two expansion ring in the middle with a fine wire tied anchor cable.
Before installing the anchor cable to the anchor hole, check whether the anchor cable number is consistent with the hole number, and confirm that it is correct, then clear the hole once with high-pressure wind, and then proceed to install the anchor cable.
Pay attention to the following four points when installing anchor cables.
① check the position of the positioning slurry stop ring and slurry restriction ring and replace them if damaged according to technical requirements.
② Check the position and smooth flow of the exhaust pipe.
③ Send the anchor cable into the hole, stop pushing when the positioning stop ring reaches the hole opening, and install the grouting pipe and one-way valve gate.
④After the anchor cable is in place, check again whether the exhaust pipe is smooth, if not, pull out the anchor cable and re-feed the cable after troubleshooting.
In the process of prestressed anchor construction, the following points must be paid attention to.
(1) The hole drilling must strictly control the hole formation error, the inclination, and horizontal angle error should be controlled below 1 degree, the hole slope deviation should be less than 1/50, try not to disturb the rock layer around the hole, and continue to blow the hole for at least 10 minutes from the bottom of the hole to the outside after the drilling is finished.
(2) When making anchor ropes, prevent the anchor ropes from twisting and bending to minimize the secondary stress; make sure the anti-corrosion of the free section of the anchor ropes, apply anti-corrosion oil, and add plastic sleeves according to the design; for the anchor section, it must be degreased to enhance the adhesion between the anchor ropes and the mortar.
(3) The anchor beam is the direct stress member of anchor cable tensioning, so the bearing surface of the mat should be smooth and perpendicular to the axis of the anchor cable.