Shandong Anchor Construction Characteristics

Shandong anchor construction characteristics

1. Shandong anchor positioning line

First according to the design drawings with a latitude and longitude meter measured and released the construction area of the anti-floating anchor hole position, with wooden stakes or steel bars for marking and numbering. Allowable deviation of anchor hole position is not more than 50mm.

2. Rig in place

After measuring and releasing the anchor holes, the drilling rig can be put into position. Use wooden square to cushion the drilling rig smoothly, to ensure that the drilling process will not have a large shake and affect the quality of the hole. Adjust the perpendicularity of the drill pipe with compass meter or hanging line method. Verticality requirements ≤ 1, the drill bit is required to be aligned with the position of the anchor hole to be constructed. The drilling can be started only after the hole position is confirmed by the signature of the manager.

3.Correct drilling

The diameter of the anchor hole is 150mm, the deviation of the hole position shall not be more than ±50mm, combined with the actual site, in the process of hole formation, the construction personnel should always pay attention to the changes of the slurry in the hole, adjust the construction process, to ensure that the formation of the hole is smooth. The depth of the hole is generally required to be 20-30cm deeper than the design depth, such as the collapse of the hole in the drilling process, mud circulation can be used to protect the wall into a hole. When drilling into the rock layer, the management personnel should confirm on site and make a record of the upper elevation, bottom elevation and total depth of the rock layer. Each anchor must make the original records of the whole drilling in detail.

4.Hole cleaning

First use mud to clear the hole, and then use pressure pump to wash the hole, discharge the slag in the hole, until the hole is clean, no large amount of slag until, pay attention to clearing time should not be too long, in order to prevent the collapse of the hole to affect the quality of grouting.

5. Lower anchor

(1) Check whether the grouting pipe is cracked or clogged, and whether the interface is firm to prevent cracking and running when the pressure is increased; (2) tie a 30mm diameter grouting pipe to the anchor, and tie it loosely and tightly, so that it can be pulled out more easily after grouting. The lower end of the grouting pipe is generally 150mm shorter than the lower end of the anchor body, and the lower end of the pipe mouth is temporarily closed with tape or cement bag to prevent the soil in the hole from blocking the grouting pipe mouth when anchoring; (3) Use the tower crane or drilling rig frame to lift the anchor and grouting pipe together into the hole, and avoid the anchor twisting, bending and loosening of the parts when putting it in place. If the rod can not be lowered to the bottom of the hole during the anchoring process, the rod should be pulled out and re-sweep the hole with the drilling rig before anchoring; (4) After the anchor rod is lowered to the hole, measure the elevation of the top to make the whole level.

6.Pressure grouting

Grouting is an important process of anchor construction, must be carried out seriously, the role of grouting: fill the pores in the soil layer, the formation of anchor solids, to prevent corrosion of anchor reinforcement, the formation of anchor pull-out resistance. After clearing the hole of the anchor can be grouted with the pressurized grout pump, grouting using the bottom of the hole back to the grout method.