JPH0531608B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a removable anchor that can reliably support earth retaining walls, etc. during use, and that can be easily removed after use. .

<Conventional technology> Various removable anchor construction methods have been developed in which the anchor is removed from the ground after construction is completed.

The present invention relates to a so-called coring-type removable anchor, which removes the anchor by creating a hollow hole and releasing the tension material from the restraint of the grout material.

The principle of the removable anchor construction method is to surround the core material with multiple PC steel wires as a tension material.
During removal, the core material is first pulled out, the tension members are released from the restraints of the grout, and the anchors are removed by pulling out the tension members such as prestressed steel wires one by one.

<Problems to be Solved by the Present Invention> How can the anchor used in the above-mentioned core removal type anchor method easily create a large-sized hollow hole inside each PC steel wire? The focus is on that.

The present invention has been made in view of the above-mentioned points, and can be easily inserted into the inside of a PC steel wire arranged in a substantially cylindrical shape.
It is also possible to create large-sized hollow holes, and it does not require large force to pull out the tendons.
The purpose is to provide a removable anchor.

<Means for Solving the Problems> The present invention provides a core wire, a core material that covers the core wire and has a plurality of projections protruding in the longitudinal direction, and an outer periphery that is removably coated on the outer periphery of the core material. The present invention relates to a removable anchor characterized in that it has a coating and a tendon disposed between adjacent protrusions on the outer periphery of the outer coating.

<Example> Next, the removable anchor of the present invention will be explained based on the drawings. (Fig. 1) (a) Overall description The removable anchor of the present invention includes a prismatic core material 1 made of vinyl chloride, for example, and a plurality of PC steels located along the four longitudinal sides of the core material 1. It is a rod-shaped body made up of a tension material 2 such as a wire.

The distal end portion thereof is defined as a fixed length portion a, the proximal end thereof is defined as a tensioned end portion b, and the space between the two is defined as a free length portion c.

(B) Core material The core material 1 is a prismatic body made of, for example, vinyl chloride, and protrusions 11 for holding the tension material 2 are installed on its four longitudinal sides.

Adjacent protrusions 11 are configured to sandwich a tendon material 2, which will be described later, located on one side of the core material 1.

Further, the outer circumferential surface of the core material 1 is coated with a lubricant such as grease and then covered with a thin outer circumferential film 12.

Furthermore, a core wire 13 made of a PC steel wire or the like is positioned in the longitudinal direction at the center of the core material 1, and its outer periphery is filled with cement paste S to fix the core wire 13 within the prismatic core material 1.

(c) Tensile material As the tension material 2, a plurality of PC steel wires or the like with a circular cross section and slightly longer than the length of the predetermined anchor hole A are used.

Then, the tension material 2 in the portion corresponding to the free length part c of the removable anchor is covered with a sheath material or the like and filled with grease, etc., to make it an unbonded type in which the tension material 2 is not directly restrained by grout material G, etc., which will be described later. .

Next, a method of using the removable anchor of the present invention will be explained.

(b) Inserting the anchor and pouring grout Insert the anchor into the anchor hole A drilled in the specified ground from the fixed length part a of the removable anchor.

When the fixing length part a reaches a predetermined depth, grout material G is injected.

The grout material G has hardened and the tension member 2 of the anchor length part a
However, the tension material 2 at the free length part c is directly connected to the grout material G by the sheath material covering it.
shall not be bound by.

Once the anchoring length part a is fixed by the grout material G, a tension force is applied to the tensioned end part b of the tensioning material 2 to serve as an anchor.

(b) Removal of tendons After anchor work is completed, remove the anchors.

[Removal of core material] (Figure 2) First, core material 1 is removed from the anchor.

Since the core material 1 is edged from the grout material G by the outer circumferential film 12, it is not restrained by the hardened grout material G, and can be peeled off and easily pulled out.

First, a tensile force is applied to the core wire 13 of the core material 1.

Since the core wire 13 is integrally bonded to the surrounding core material 1 by the cement paste S, when the core wire 13 is pulled, the core material 1 and the core material 1 come out of the outer peripheral film 12.

At this time, since a lubricant such as grease is applied between the outer peripheral film 12 and the core material 1, the core material 1 can be pulled out smoothly.

When the core material 1 is removed, a hollow hole 3 surrounded by the outer peripheral film 12 of the core material 1 and a plurality of tendons 2 is formed. (Figure 4) [Removal of tendons] Next, remove the tendons 2.

Since the inner sides of the tendons 2 and the outer peripheral coating 12 bound by the grout material G are hollow holes 3, the binding of the tendons 2 is loosened, and the tendons 2 can be easily pulled out.

<Other Embodiments 1> It is also possible to use a core material 1 formed as a fixed-sized divided body as shown in FIG.

In actual use, the core material 1 of a fixed size is passed through and added to the long core wire 13 until a predetermined total length is obtained, and the core material 1 is connected with the core wire 13 for use.

Here, it is necessary to prevent the cement paste S injected to fix the core wire 13 and the core material 1 from leaking from between the core materials 1.

As a means to prevent leakage of the cement paste S, for example, a joint tube 14 may be provided protruding from one end of the core material 1.

The joint tube 14 has an outer diameter inscribed in the wall of a hole formed in the axis of the core material 1, and is used with only one end of the joint tube 14 fixed to the core material 1.

When the core material 1 of fixed size is adopted as in this embodiment, it is very convenient to transport, handle, and store the core material 1.

<Other Example 2> When removing the core material 1, the smaller the frictional resistance between the core material 1 and the outer peripheral film 12, the easier the core material 1 can be removed.

Therefore, it is conceivable to carve fine continuous grooves in the axial direction around the entire circumference of the core material 1 and bring the outer circumference of the core material 1 into line contact with the outer peripheral coating 12 to reduce the frictional resistance.

<Other Embodiment 3> It is also possible to use one in which the outer peripheral film 12 is divided into a plurality of parts in the longitudinal direction of the core material 1.

Particularly, both edges of each of the divided outer peripheral films 12 are provided with known connecting means such as meshing or fitting between a male mold and a female mold.

In the case of this embodiment, when attaching the outer circumferential coating 12 to the core material 1, each of the divided outer circumferential coatings 12 can be assembled instantly, and moreover, the labor involved in the attachment work can be significantly reduced.

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

(b) The core material is separated from the grout material by the outer peripheral film, and the core material is in close contact with the central core wire, so by pulling out the core wire, the core material can be easily pulled out from within the surrounding tendon material. be able to.

Therefore, a hollow hole can be easily created in the tendon material, and the tendon material can be easily removed.

(b) Since the tendons are arranged between adjacent protrusions of the core material, the contact area between the tendons and the grout material is reduced.

As a result, when pulling out the tension material after removing the core material, it can be easily peeled off and pulled out easily.

(c) Conventionally, the anchors used in the removable anchor method had a complicated structure, and had drawbacks such as increased diameter and weight.

The anchor of the present invention has a very simple structure for removal and is therefore convenient to handle.

[Brief explanation of drawings]

Figure 1: An explanatory diagram of the removable anchor of the present invention, Figure 2: An explanatory diagram of the core material being pulled out, Figure 3: An explanatory diagram of the anchor work, Figure 4: An explanatory diagram of the core material being removed. , FIG. 5: An explanatory diagram of another embodiment. 1...core material, 2...tension material, 3...hollow hole, A
...anchor hole.

Claims (1)

[Scope of Claims] 1. A removable anchor comprising: a core wire; a core material covering the core wire and having a plurality of protrusions protruding in the longitudinal direction; and a peripheral film removably covering the outer periphery of the core material; A removable anchor comprising: a tension member disposed between the adjacent protrusions on the outer periphery of the outer peripheral membrane.