JPH025206B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a removable anchor that can reliably support an earth retaining wall or the like during use and that can be easily removed from the installation site after use.

〈〉 Purpose of the invention [Industrial application field] construction.

[Prior Art] Various types of removable anchors have been developed that are removed from the ground after construction is completed.

The present invention relates to a removable anchor that removes tendons by creating a hollow hole.

The principle of a removable anchor using the core removal method is that the core material is surrounded by multiple PC steel wires to act as a tension material.When removing the core material, the core material is first removed, and then the PC steel wires are removed from the bundle of PC steel wires that have weakened their cohesion. This method involves pulling out and removing the tension members one by one.

[Problems to be Solved by the Invention] In removable anchors using the core removal method, there is always the problem of how to easily create large-sized hollow holes inside each PC steel wire. .

[Object of the present invention] The present invention provides a removable anchor in which tendons can be easily removed by creating a large hollow hole inside a cylindrical PC steel wire. The purpose is to

In other words, the present invention consists of an unbonded core material, a spacer made up of a plurality of pieces located around the core material and which disintegrates when the core material is removed, and a tension spacer located around the outer periphery of the core material and spacer. This relates to a removable anchor consisting of

<> Structure of the Invention [Means for Solving the Problems] Next, the removable anchor of the present invention will be explained based on the drawings.

The removable anchor of the present invention has a plurality of annular spacers 3 encircled at the tip of a core member 2, which is a hollow cylindrical body, and a plurality of tension members 1 surrounding the core member 2 in a cylindrical shape. (Figures 1 and 2) The tip of the anchor inserted into the insertion hole 4 is the anchor length part a, and the one end exposed to the outside from the fastening part 5 of the ground is the tension end b, and further between the two. Let be the free length c.

(a) Tensile material As the tension material 1, use a plurality of PC steel wires or the like having a circular cross section and slightly longer than the length of the insertion hole 4.

The tension material 1 in the portion corresponding to the free length part c of the removable anchor is made into an unbonded type that is not bound by grout material G, etc., which will be described later, by applying grease around the tension material 1.

(b) Core material The core material 2 is a hollow cylindrical body made of a steel pipe or the like, and the core material 2 is an unbonded type that is not restricted by grout material G, etc., which will be described later, such as applying grease around the core material.

The hollow portion becomes an injection path when grouting material G is injected.

The diameter thereof is sufficiently larger than the tension material 1, and the core material 2 is a member that fits into the hollow portion of a plurality of tension materials 1 formed into a cylindrical shape.

(C) Spacer (FIGS. 1 and 8) The spacer 3 is an annular member that is attached to the fixing length section a of the core material 2 at a plurality of locations.

The annular spacer 3 is formed by a cane-shaped piece 32 obtained by dividing a hollow disk into a plurality of pieces.

However, when the spacer 3 is located on the outer periphery of the core material 2, it is formed in such a dimension that a distance S exists between one piece 32 and an adjacent piece 32.

Furthermore, a semicircular recess 31 is provided on the outer circumferential surface of each piece 32 so that the tension material 1 can be fitted therein, and as will be described later, the tension material 1 is fitted into the recess 31 to form a removable anchor. Form.

Therefore, when the core material 2 is removed, the spacer 3, which forms a disk around the core material 2 by being sandwiched between the core material 2 and the tension material 1, moves in the direction of narrowing the interval S between each piece 32. It breaks down into pieces. (7th
Figure) (d) Formation of a removable anchor A removable anchor consisting of each of the above members has a core material of 2.
Tensile material 1 is installed on the outer periphery of the specimen parallel to its axis.

As shown in FIG. 1, the tension material 1 of the fixing length part a is fitted into the recessed portion 31 of the spacer 3 which is ringed at regular intervals.

The tension material 1 fitted into the recessed portion 31 is positioned so as to press each piece 32 of the divided spacer 3 against the core material 2, so that the tension material 1 and the core material 2 are separated at that part.
A gap is created in between.

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

(b) Insertion of removable anchor and injection of grout Insert the removable anchor into the insertion hole 4 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, the grout material G is injected into the hollow part of the core material 2.

The grout material G has hardened and the tension material 1 of the anchorage length part a has been cured.
is restrained, but the free length c of the core material 2 and tension material 1
Since the part is an unbonded type, it is not restricted by the grout material G.

After 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 1 of the fastening part 5 to serve as an anchor. (Figures 2 to 4) (b) Removal of tendons (Figures 5 to 7) After anchor work is completed, remove the removable anchor.

[Removal of core material] First, the core material 2 is removed from the insertion hole 4.

Since the core material 2 is of an unbonded type, it is not restrained by the hardened grout material G and can be easily pulled out.

When the core material 2 is removed, a cavity 6 surrounded by a plurality of tendons 1 is created.

[State of the fixing length portion] In the fixing length portion a, the tension material 1 was pushed apart by the spacer 3 in the centrifugal direction of the insertion hole 4.

However, by removing the core material 2, the tension material 1, which had been forcibly spread out, pushes out each piece 32 of the spacer 3 into the cavity 6 by its elasticity, and becomes straight.

As a result, the group of pieces 32 that had formed a disk shape around the core material 2 disassembled, and the tension material 1, which had been restrained to the grout material G by the spacer 3 section, due to its elasticity, Freed from G.

[Removal of tension material] The tension material 1 is of an unbonded type at the free length portion c, and is released from the grout material G at the anchorage length portion a as described above, so that the tension material 1 can be easily removed.

(C) Other Examples The spacer 3 of the above example was formed by a plurality of cylindrical pieces 32, but as shown in FIG. It is also conceivable to form it into a wedge shape.

In this case, when a cavity 6 is created by removing the core material 2, the tapered pieces 32 slide into the cavity 6 and the binding of each piece 32 becomes loose.

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

(b) A large cavity can be easily created by simply removing the core material of the unbonded type.

(b) By removing the core material, the binding of the spacer consisting of a plurality of pieces is loosened, and the tension material that was spread out and restrained by the grout material is released from the grout material.

(c) It has a simple structure consisting of only a core material, spacer, and tension material.

[Brief explanation of drawings]

Fig. 1: An explanatory diagram of the anchoring length of the removable anchor of the present invention, Figs. 2 to 7: An explanatory diagram of how to use the removable anchor of the present invention, Fig. 8: An explanatory diagram of the spacer, Fig. 9: Explanatory diagrams of other embodiments. 1: Tensile material, 2: Core material, 3: Spacer, 4:
Insertion hole, 5: Fastening portion, 31: Recessed portion, 32: Top.

Claims (1)

[Scope of Claims] 1. An unbonded type core material, a spacer consisting of a plurality of pieces arranged at intervals in the circumferential direction on the circumferential surface of the core material, and tension located on the outer periphery of the core material and the spacer. A removable anchor consisting of wood.