1. prestressed anchor construction method: select a special drilling rig for soil anchor to drill holes. The diameter of the outer casing is φ хх mm, and the drill bit is hollow, which is directly installed on the outer casing, and the outer diameter of the drill bit is φ хх mm. After the hole is formed, it is confirmed that there is no residual soil core in the casing, so as to ensure that the tie rod bundle can be put into the hole smoothly. zmjt052 .

2. Treatment and removal of mud water: the mud water generated in the process of pore-forming is treated and removed in time, and the mud is sent to the collecting well through the drainage ditch, and the clean water is pumped out by the pump, and the mud is transported away by the tanker.

3. Trip out the drill pipe: After drilling is completed, trip out the drill pipe in time, which is conducive to the next casing trip.

4. Place anchor rod: After the anchor rod is delivered to the site, check whether the grouting plastic pipe is in good condition. After casing running, the anchor rod should be exposed out of the hole at least 2m to ensure the tensioning requirements.

5. Casing pulling: After running the pipe anchor, pull out the casing. This process is as fast and continuous as pulling a drill pipe.

6. Grouting: the grouting operation starts from the bottom of the hole, and the drainage and exhaust in the hole are ensured smoothly during the grouting process until the end. The grouting operation is uninterrupted, and the grouting pressure is 0.3 ~ 0.5 MPa.

7. Maintenance of anchorage: After grouting, the anchorage should be maintained immediately, and the maintenance time should be determined according to the laboratory ratio test.

8. Anchor tensioning: when the anchor body reaches the design strength, tensioning shall be carried out. Anchorage tensioning is completed by a set of special equipment, which consists of control box, cable jack and anchorage. The tension control stress of anchor rod is about 0.8 of the fracture stress of wire rope. The tension is operated, observed and recorded by special personnel, and the load-displacement curve is drawn.