JPH0377891B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a removable anchor that can be easily removed.

[Prior Art] Various types of removal anchors have been developed for removing anchors from underground after construction is completed.

Among the removable anchors, there is one in which a conical wedge portion that widens toward the end is installed at the tip of an anchor core material, and an outer peripheral member is placed around the core material and is restrained by the grout material.

Such removal anchors are removed in the following manner.

That is, upon removal, the core material is first pulled out.

Then, the wedge portion located at the tip pushes out the outer peripheral member located around the core material.

The extruded outer circumferential member destroys the grout material, thereby removing the anchor, which is released from its restraint, out of the hole.

[Problems to be Solved by the Present Invention] The wedge-type removal anchor as described above has the following problems.

(b) This method destroys the grout material by pushing the outer peripheral member outward by the force of the wedge, so if the strength of the grout material is too strong, it will be difficult to destroy and impossible to remove.

(b) From the above, there is a limit to the strength of the grout material (200 kg/cm ² or less), and the anchor itself cannot be required to have very high strength.

(c) It is difficult to manage the mixture of admixture (air) to adjust the strength of grout material.

[Object of the present invention] The present invention has been made in view of the above-mentioned points, and it is possible to project the grout to the outside of the outer circumferential member of the core material without being affected by the strength of the grout material. To provide a removal anchor that is easy to remove.

[Configuration of the Present Invention] Next, the removal anchor of the present invention will be explained based on the drawings.

The removal anchor of the present invention includes a core material 1 having a wedge portion 11 at its tip, a tendon material 2 located around the core material whose tip end fits into a tendon groove 13 of the wedge portion 11, and a wedge portion 11 which will be described later. It consists of a hollow material 3 located between each piece. (Fig. 2) (a) Core material and wedge part (Figs. 1 to 3) The core material 1 is an unbonded PC steel wire, and the wedge part 11 is installed at the tip thereof.

The wedge portion 11 is a member in which the core material 1 is fitted onto the axis of a conical member, and two portions having a cross-sectional shape symmetrical to the core material 1 are cut out.

Then, the core material 1 passing through the axis of the wedge portion 11 is fixed to the lower surface 15 of the wedge portion 11 with a fixture 16, so that the core material 1 and the wedge portion 11 are integrally formed. (Fig. 3) As shown in Fig. 1, a flat part 12 is formed on each side surface facing the notch of the wedge part 11,
A tension material groove 13 for fitting the tension material is recessed in parallel to the axial direction of the wedge portion 11.

The tension material groove 13 is formed with an inclination so that it is deeper than the diameter of the tension material 2, which will be described later, on the upper surface 14 side of the wedge portion 11 and becomes shallower on the lower surface 15 side.

That is, the tension material 2 fitted in the tension material groove 13 fully enters the inside of the wedge portion 11 on the upper surface 14 side of the wedge portion 11, and is exposed to the outside of the wedge portion 11 from the flat surface portion 12 as it goes toward the lower surface 15 side. .

(b) The tension member 2 is made of flexible PC steel stranded wire, and its tip is fitted into the tension member groove 13 of the wedge portion 11.

(c) Cavity material Unbonded PC steel wires are used as the cavity material 3, and two wires are placed symmetrically with the core material 1 in between, parallel to the core material 1, and adjacent to the tendon material 2.

The tip thereof is held between the opposing flat parts 12 of each piece of the wedge part 11.

The diameter is such that the outer circumferential surface of the hollow material 3 can substantially close the tendon grooves 13 carved in the flat portions 12 that sandwich the hollow material 3.

In other words, the hollow material 3 is located in the tension material groove 1 of the flat part 12.
3, and above the wedge portion 11, it is located adjacent to the tendon.

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

(a) Anchor action (FIG. 4) An anchor hole A is drilled by a known method, the removal anchor of the present invention is inserted from the wedge portion 11 side, and the grout material G is filled.

After the grout material G has hardened, a tension force is applied to the tensioned end of the removed anchor to serve as the anchor.

(b) Removal of hollow materials (Figures 3 and 5) When removing the anchor, first pull out the two hollow materials 3 to create a hollow hole 4.

Since the hollow material 3 is made of unbonded type 2 PC steel wire, it is easy to pull it out.

Since the hollow material 3 was adjacent to the tendon groove 13, the hollow hole 4 after removal is also adjacent to the tendon groove 13, and the two are connected as one space.

Further, above the wedge portion 11, the cavity 4 is located parallel to the core material 1 and adjacent to the tendon material 2.

(c) Pulling out the core material (Figures 3 and 5) After the hollow material 3 is removed, the core material 1 is pulled out.

Since the core material 1 uses an unbonded type PC steel wire, its drawing itself is easy.

However, since the core material 1 has a wedge portion 11 at its tip, by pulling up the core material 1, the wedge portion 1
1 will be increased.

The depth of the tendon groove 13 becomes shallower toward the lower surface 15 of the wedge portion 11.

As a result, the tension material 2 whose tip end is fitted into the tendon material groove 13 is pushed out from the plane portion 12 of the wedge portion 11 as the wedge portion 11 rises.

The tendon material 2 is adjacent to the hollow hole 4, and since the rising tendon groove 13 and the hollow hole 4 are connected as one space, the tendon material 2 is pushed out into the hollow hole 4 without difficulty.

(c) Removal of tendon material By pulling up the wedge portion 11 over the entire length of the anchor, the tendon material 2 is pushed out over its entire length into the cavity 4 and released from the restraint of the grout material G.

Therefore, its extraction can be carried out extremely easily.

[Effects of the present invention] Since the present invention has been described above, the following effects can be expected.

(b) By removing the hollow material, a hollow hole is created adjacent to the tendon material.

Therefore, rather than pushing the tendon apart with the wedge, the tendon can be easily released from the grout by simply moving the tendon into the cavity using the inclined tendon groove of the wedge. .

(b) Do not destroy the grout by forcing the tendons apart.

Therefore, it is possible to use a grout material with high strength, and it can be used as a highly reliable and strong anchor.

(c) Since it is not affected by the strength of the grout material, it is no longer necessary to manage the mixing ratio of the mixture, which was difficult in the past.

[Brief explanation of drawings]

Figure 1: Exploded explanatory diagram of the wedge part used in the present invention,
Figure 2: An explanatory diagram of the wedge portion of the anchor used in the present invention, Figure 3: An explanatory diagram of the tension member when pulling up the core material, Figures 4 and 5: An explanatory diagram of the hollow member before and after removal. . 1: core material, 2: tendon material, 3: cavity material, 4: cavity hole, 11: wedge portion, 12: plane portion, 13: tendon groove, 16: fixture, G: grout material.

Claims (1)

[Scope of Claims] 1. An unbonded type core material, a wedge portion located at the tip of the core material and expanding toward the end, and the wedge portion has a notch parallel to the axis on the circumferential surface at a symmetrical position with respect to the core material. and a tendon groove in the axial direction that is deeper than the diameter of the tendon on the upper surface of the wedge and becomes shallower toward the lower surface on the side surface facing the notch, and is removed adjacent to the tendon and the tendon groove. A removable anchor consisting of an unbonded hollow material that later creates a hollow hole, and a tendon whose tip fits into the tendon groove of the wedge part.