Prestressed anchorage conditions of use

Anchorage fixed (prestressed anchor) is to add a measure of retaining structures or geotechnical stability of anchorage fixing method. The method is likely to slip through the fight drilling or has slid over the sliding surface, the end of the rebar (or cable) is fixed at the bottom of the hole in the rock and soil stability, and then reinforced (or cable) tension as well as to produce a certain resilience (ie prestressed), and then the other steel (cable) end fixed to the rock and soil surfaces or retaining structures, the use of reinforced resilience of rock and soil compaction may slip or retaining structures to increase the shear strength of the sliding surface, so as to achieve the purpose of improving or retaining rock and soil structural stability.

Prestressed anchor advantages are:
1 In the high slope or cut and cover tunnel entrance used, increase the slope stability, thereby reducing the amount of excavation, but also to create conditions for early hole;
2 can be used to reinforce concrete dam or dam reservoir under normal operating conditions;
3 used to repair concrete cracks or defects can be concentrated loads spread over a wide range;
4 reinforcement cavern, caverns improve the force conditions, such as high sidewall support for the underground powerhouse and so on.
5 These advantages make it in water conservancy projects worldwide has been widely used.

Construction of prestressed anchoring procedures are:
1 pre-pull, tension devices and locking;
2 anchor segment fixed;
3 sealing grout.
4 pore;
5 series cable;
6 measured hole depth, diameter and skewness;
7 anchor head machining;
8 anchor hole direction can be divided into vertical holes, horizontal holes, tilt holes and Yang holes.
Drill hole is generally 110 ~ 150mm. Due to the tension after compression deformation, creep, relaxation anchor beams, sliding and other reasons anchoring section of material would have a prestressing losses. Therefore, the design of prestressed deal with a reasonable estimate of the loss. Generally tensioning process, using pre-tensioned pull or repeated super way to reach adjustment stress, reduce prestress loss purposes. Sometimes after the formal tension tension also be compensated. After the cable lock for general use cement grout sealing; conducted repeated when tensioned prestressed prefer to give compensation for the loss, often with impermeable material such as asphalt sealing.