JPH0516278Y2 - - Google Patents

Description

[Detailed explanation of the invention] (Industrial application field) The invention is an underground anchor for use as a permanent underground anchor for fixing legal frames to the ground or fixing foundations in construction work of buildings, etc. Relating to tension material for anchors.

(Conventional technology) Conventionally, as removable anchors and permanent anchors,
A so-called unbonded cable is used, in which a prestressed steel wire is threaded through a flexible synthetic resin sheath coated with grease.

In addition, in recent years, an unbonded cable has been mainly used for removal anchors by folding it back into a U-shape, and hooking the folded part around a fixing fitting buried in the anchor hole to fix it in the anchor hole. A device in which a PC steel wire is pulled out from one end has been developed.

On the other hand, when the unbonded cable is folded back and used in this way, the grease applied to the PC steel wire and the synthetic resin sheath covering the outside of the cable cause
In recent years, PC steel wire has come to be used in permanent anchors where rust prevention is important because it has a double rust prevention effect over the entire length.

(Problem to be solved by the invention) As mentioned above, in the case of underground anchors in which the unbonded cable is folded back in a U-shape and wrapped around the fixing metal fitting, when wrapping the unbonded cable, it is necessary to synthesize the unbonded cable using a bender. Because it is necessary to apply pressure from the outside of the resin sheath to deform it, the sheath is easily damaged, and in some cases, the sheath may crack.
There was a problem in that the rust prevention effect of the unbonded cable was impaired, making it unsuitable as a permanent underground anchor.

The present invention was made with the aim of solving such conventional problems.

(Means for Solving the Problems) The feature of the tensile material for underground anchors of the present invention, which solves the conventional problems as described above, is that it is buried with concrete in an anchor hole that is excavated underground. A tensile member for an underground anchor in which the approximately central portion is hung around a fixing fitting in the anchor hole, which is folded back into a U-shape, and both ends are introduced outside the anchor hole,
Almost the entire structure is made up of a PC steel wire that is slidably inserted into a flexible synthetic resin sheath, and at least the outer surface of the sheath at the U-shaped folded portion is covered with a synthetic resin cloth made of reinforced synthetic resin fibers. It's because I pasted it on.

(Function) In this tensile material for underground anchors, the reinforced synthetic resin fiber cloth attached to the folded part protects the outer surface of the synthetic resin sheath and prevents cracks from forming when it is wrapped around the fixing metal fitting. In addition, the fabric will permanently protect the sheath after it is buried in the anchor concrete, and the sheath will not be damaged even if the PC steel wire is pulled due to an earthquake or the like and the sheath and anchoring fittings rub against each other. Prevented.

(Example) Next, an example of implementation of the present invention will be described with reference to the drawings.

Figure 1 shows a permanent underground anchor for fixing slope protection blocks. In the figure, 1 is the anchor hole reduced in the ground, 2 is the slope protection block, 3 is the tensile material fixed at the outer end, and 4 is This is anchor concrete that is fixed by injecting cement milk. Anchor hole 1
Three tension members 5a, 5b, and 5c are folded back inside, and a pair of leading ends at both ends are fixed to a fixing body 3 to support the slope protection block 2. Each of the tension members 5a to 5c uses a so-called unbonded cable in which a PC steel wire is slidably inserted into a synthetic resin sheath, and the center portion of each of the tension members 5a to 5c is attached to the fixing metal fitting 6. The anchor fittings 6 are wrapped around each other and buried in the anchor hole 1 at different depths.

As shown in FIG. 2, a synthetic resin cloth 7 made of reinforced synthetic resin fibers (commonly known as FRP) is adhered to the portion of each of the tension members 5a to 5c wrapped around the fixing fitting 6 using an adhesive.

The synthetic resin cloth 7 is preferably attached to a portion corresponding to the entire length of the fixing metal fitting 6, but it may be attached only to the folded portion that contacts the bender. Further, it is preferable to stick the synthetic resin cloth 7 in a state where it is clogged with an adhesive. By doing so, even if a crack occurs in the sheath, the synthetic resin cloth 7 can be stuck. This prevents water from entering and does not impair the rust prevention effect.

The fixing metal fitting 6 has a concave groove 8 formed in a U-shaped arrangement on its distal end side for passing a tensile material therethrough. A flange 9 is formed on the outer periphery of the rear end side of the fixing metal fitting 6, and the flange 8 has tensile material guide recesses 10, 10...
... are formed in a radial arrangement. A cylindrical projection 11 is protruded from the center of the rear end surface of the fixing metal fitting 6, and a guide metal fitting 12 has a cylindrical shape on this projection 11. Tensile members 5a to 5c are attached to the outside of the guide metal fitting 12, and a wire is attached to the guide metal fitting 12. It is fixed with 13.

A bearing fitting 14 is fitted to the rear end of the guide fitting 12 . The bearing fitting 14 has cylindrical guide fitting fitting protrusions 15 and 16 protruding from both end faces, and a bearing pressure piece 17 in the form of a flange projects from the center of both. The supporting pressure piece portion 17 has the same number of guide recesses 18 as the lower fixing metal fitting 6 described above, which are formed in a radial arrangement.

Furthermore, as shown in Fig. 1, one guide metal fitting 12 and one bearing metal fitting 14 are used for the fixing metal fitting 6 of the tension member 5a that is inserted to the deepest position, and the tension member 5a is inserted between Two guide fittings 12 and two bearing fittings 14 are alternately used for the fixing fittings 6 of the tensile material 5b to be inserted, and three guide fittings 12 and three bearing fittings 14 are used alternately for the fixing fittings of the tensile material 5c inserted at the shallowest position. All of the folded ends of the tension members 5a to 5c located at the positions of the fixing metal fittings 6 and the bearing metal fittings 14 are fitted into the guide recesses 10 and 18, and the tension members 5a to 5c are placed at positions close to these. Guide metal fittings 12 on both sides of 5c
It is fixed with a wire 13.

In addition, in the underground anchor of this embodiment, the tensile force applied to each tensile member 5a to 5c is transmitted to and supported by the anchor concrete 4 via each anchoring fitting 6 and bearing pressure fitting 14, and each Pressure fitting 14
As for the anchoring fitting 5 on the entrance side of the anchor hole 1, the number of tensile members attached to the outside increases by two, and the adhesion area of concrete decreases accordingly, but the bearing fitting 14 Since the number of anchoring metal fittings is large, the supporting force against the concrete is uniform for each anchoring metal fitting.

(Effects of the invention) As mentioned above, the tensile material for underground anchors of the present invention has a synthetic resin cloth made of reinforced synthetic resin fibers attached to the U-shaped folded part, so that it is easy to wrap around the fixing metal fittings. Or, when the synthetic resin sheath is subsequently rubbed against the fixing fitting, no scratches such as cracks occur, and the rust prevention effect is no longer impaired permanently.

[Brief explanation of drawings]

The drawings show an example of the implementation of the present invention.
The figure is a cross-sectional view of the entire underground anchor, Figure 2 is a cross-sectional view of the fixing metal part, Figure 3 is a front view of the fixing metal fitting, Figure 4 is a side view of the same, and Figure 5 is a front view of the bearing metal fitting. be. DESCRIPTION OF SYMBOLS 1... Anchor hole, 4... Anchor concrete, 5a, 5b, 5c... Tensile material, 6... Fixing metal fitting, 7... Synthetic resin cloth, 8... Concave groove, 9... Flange, 10, 17... ... Guide concave notch, 12... Guide metal fitting, 14... Bearing pressure fitting, 16... Bearing pressure piece part.

Claims (1)

[Scope of utility model registration request] The approximately central part is hung around the anchor hole fixing fitting which is buried with concrete in the anchor hole excavated and formed in the ground, and is folded back into a U-shape.
A tensile material for underground anchors with both ends led out of the anchor hole is almost entirely composed of a PC steel wire that is slidably inserted into a flexible synthetic resin sheath, and has at least the U-shape mentioned above. A tensile material for underground anchors, characterized in that a synthetic resin cloth made of reinforced synthetic resin fibers is attached to the outer surface of the sheath of the folded part of the shape.