JPH0137532B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for joining a sheath in an anchor.

<B> Purpose of the present invention [Industrial application field] Can be used for a variety of purposes such as vertical anchors for structures that generate tensile force, anchors for structures that receive various horizontal forces [Prior art] Generally Corrosion prevention of the anchor body, which is made of prestressing steel, is a problem for anchors.

To explain the conventional anchor, as shown in Fig. 3, the free length E of the anchor body A is attached to the tail end of a corrugated pipe C that covers the fixed length B of the anchor body A made of prestressing steel. This anchor is formed by encasing a sheath formed by integrally welding a smooth tube D to be sheathed, and filling the corrugated tube C with anti-corrosive oil or cement paste.

[Problems to be Solved by the Present Invention] The following problems remain to be solved in the conventional anchor sheath coupling method.

(1) Corrugated tube C covering fixing length part B and free length part E
Since the two pipes of the smooth pipe D covering the pipes are joined by welding, the welding operation is time-consuming.

(2) The welding work to connect the corrugated pipe C and the smooth pipe D requires advanced welding techniques, and the watertightness of the welded part is incomplete.

(3) If the welding of the joints between both pipes is incomplete, cracks are likely to occur, and corrosion-preventing oil etc. may leak from these cracks and cause damage to anchor body A.
Since it comes into direct contact with water, gas, etc., it causes corrosion, and as a result, the proof strength of the permanent anchor deteriorates significantly.

[Object of the present invention] The present invention has been made in order to solve the above-mentioned problems, and it is possible to join the sheath of the fixed length part and the free length part by a simple operation, and to achieve high water-stopping property. The purpose of the present invention is to provide a method for joining sheath materials in anchors that can ensure the following.

[Structure of the Invention] The method for joining the sheath in the anchor of the present invention will be described below with reference to the drawings. First, the main members used in the method for joining the sheath will be described.

<1> Sheath material FIG. 1 shows an example of a sheath material.

This sheath material consists of a corrugated tube 2 that covers the fixed length of the anchor cable 5, and a straight tube 3 that covers the free length.

<2> Joint Tube The joint tube 1 is a tube shaped so that it can be fitted into and connected to the free ends of the corrugated tube 2 that covers the fixed length portion of the anchor cable 5, and the straight tube 3 that covers the free length portion of the anchor cable 5, respectively.

On one side of the joint tube 1, a corrugated portion 11 that can be in close contact with the inner wall of the corrugated tube 2 is formed, and on the other side, a cylindrical portion 12 that can accommodate the straight tube 3 is formed.

Note that the shape of the corrugated portion 11 is, for example, when the corrugated tube 2 has a helical unevenness on the circumferential surface.
For example, the wave portions 11 are formed in the same shape.
It is formed to correspond to the shape of the circumferential surface of the corrugated tube 2.

<3> Shrinkable tube The shrinkable tube 4 is made of, for example, a synthetic resin-based heat-shrinkable material that has a larger diameter than the outer diameter of the joint tube 1 and has a full length that can sufficiently cover the joint between the corrugated tube 2 and the straight tube 3. It is a tube.

The shrink tube 4 does not need to have a part of the tube corrugated like the joint tube 1, but a normal cylindrical tube as shown by the dashed line in FIG. 2 is used.

[Method of Joining] Next, a method of joining the corrugated pipe 2 and the straight pipe 3 using the above members will be described.

(1) Joint pipe connection The corrugated pipe 2 and straight pipe 3 are joined outside the hole before the anchor cable 5 is inserted into the anchor hole 6.

As shown in FIG. 2, the anchor cable 5 and the grout hose 51 are coated with a corrosion-resistant coating.
The openings at both ends of the joint tube 1 are fitted into the free ends of the corrugated tube 2 and the straight tube 3 into which the joint tube 1 is inserted, respectively.

When fitting the corrugated portion 11 of the joint tube 1 to the free end of the corrugated tube 2, a clay-like sealing material 5 is placed between the inside of the corrugated portion 11 and the anchor cable 5 in advance.
2 is interposed.

As the sealing material 52, for example, asphalt or the like can be used.

Next, the tip of the corrugated pipe 2 is connected to the grout hose 51.
Grout is injected into the corrugated tube 2 with the proximal end closed with a sealing material 52 using a separate grout hose to seal the corrugated tube 2.

As a result, the free ends of the corrugated tube 2 and the straight tube 3 are temporarily connected by the joint tube 1.

(2) Exterior of the shrink tube A shrink tube 4 is wrapped around the outer periphery of the connecting portion of the corrugated tube 2 and the straight tube 3, which have been temporarily connected using the joint tube 1.

When the shrink tube 4 is to be sheathed, an adhesive is applied between the shrink tube 4 and the corrugated tube 2, a water stop material 53 is interposed, and the shrink tube 4 is sheathed.

This water stop material 53 is used when the unevenness of the joint pipe 1 is continuous in a spiral shape and forms a single groove.
For example, a water stop material 53 such as seal rubber is used.

Furthermore, in the case of a type in which the corrugated pipe 2 has unevenness that is not a single continuous unevenness but is formed independently, the water stop material 53 can be omitted.

(3) Heat shrinkage of the shrink tube Next, first heat shrink both ends of the shrink tube 4 using a simple burner, etc., and then heat the entire area of the shrink tube 4. The shrink tube 4 starts shrinking while compressing the joint tube 1. As a result, it deforms into a wave shape following the circumferential surface of the joint tube 1.

Water stop material 53 between joint pipe 1 and shrink pipe 4
As a result of being compressed, if both pipes 1 and 4 and water stop material 5
Even if there is a gap between the two parts, the gap is eliminated and the water-stopping properties of the joint are improved.

After the completed anchor material is inserted into the anchor hole, the hole is filled with grout to secure the tip, and the proximal end of the anchor is placed under tension, and used according to a known construction method.

(4) Other embodiments (FIG. 4) In addition to the embodiments described above, it is also conceivable to join the corrugated pipe 2 and the straight pipe 3 without using the joint pipe 1 used as a reinforcing material.

That is, the shrinkable tube 4 is placed on the exterior of the joint between the two tubes 2 and 3 arranged on the same line with a waterproof material 53 interposed therebetween, and the shrinkable tube 4 is heat-shrinked to cover the circumferential surfaces of the corrugated tube 2 and the straight tube 3. This is a method of joining by crimping.

<C> Effects of the present invention Since the present invention has been described above, the following effects can be expected.

(1) Even if a corrugated pipe and a straight pipe have different shapes, first connect the two pipes with a joint pipe that has a joint opening of the same shape as both pipes, and then apply heat-shrinkable material to the joint. It becomes possible to sheath the tubes, heat shrink them, and join them.

Therefore, compared to conventional welding work, the connection process is not only less troublesome and simpler, but also
The reliability of the joint is improved.

(2) In addition, when wrapping a shrink pipe over the connection between a corrugated pipe and a straight pipe, if a water stop material is inserted between the shrink pipe and the corrugated pipe and the shrink pipe is heat-shrinked, the water stop material will be compressed. Since the uneven grooves are shielded, water-stopping properties are improved.

Therefore, even if external pressure is applied during tension, the water-stopping material interposed between the shrink tube and the corrugated tube will prevent the tube (sheath) from leaking.
It can reliably prevent water and gas from entering the interior, providing a high degree of corrosion protection.

[Brief explanation of drawings]

Figure 1: An overall illustration of the anchor, Figure 2: An illustration of the joint between the straight pipe and the corrugated pipe, and Figure 3:
An explanatory diagram of a conventional anchor sheath connection method, FIG. 4: An explanatory diagram of other embodiments 1: Joint tube, 2: Corrugated tube, 3: Straight tube, 4: Shrink tube, 5: Anchor cable.

Claims (1)

[Scope of Claims] 1. When joining together a corrugated tube that covers the fixed length portion of the anchor cable and a straight tube that covers the free length portion of the anchor cable, the joining portion of the corrugated tube and the straight tube is covered. This is done by sheathing the area covered with heat-shrinkable shrink tube, interposing a waterproof material between the shrink tube and the corrugated tube, and heat-shrinking the shrink tube and crimping it onto the circumferential surfaces of the corrugated tube and straight tube. A method for joining a sheath in an anchor, characterized by: