JP3195595B2 - Earth anchor with removable anchor wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground for supporting earth pressure, water pressure, a load acting on a support, etc., by fixing a high strength anchor steel wire in the back soil of the support. It is about an anchor.

[0002]

2. Description of the Related Art There are two types of earth anchors of this type, a tension earth anchor and a compression earth anchor, depending on the condition of the ground and the type of temporary structure.

[0003] The difference between the tension type earth anchor and the compression type earth anchor will be briefly described. The tension type earth anchor is formed by covering the anchoring end of an anchor steel wire with a capsule and covering the free end with a sheath tube, respectively. The anchor steel wire and the capsule are integrated with the grout material filled therein, and the anchor steel wire is pulled.

On the other hand, a compression-type earth anchor has one or a plurality of load-bearing members, which are pressure-resistant members made of steel pipes or the like, disposed at the underground end of the anchoring end, and a plurality of anchor steel wires are attached thereto. Attached, the anchor steel wire and the load-bearing body are covered with the sheath pipe, and the load-bearing body and the sheath pipe are integrated with a grout material or the like filled in the sheath pipe while leaving a free end, and the anchor steel wire is pulled. Structure.

By the way, these tensile earth anchors and compression earth anchors can reliably support the earth pressure, the water pressure, the load acting on the shoring, etc. by using a high-strength anchor steel wire. However, there is a problem that the used anchor steel wire cannot be easily removed from the ground. In addition, since the removal operation requires the use of heavy equipment such as a drawing machine and a hoist, there is a problem that it is not only troublesome but also causes an increase in construction cost.

An earth anchor for solving such a problem is disclosed in Korean Patent Publication No. 94-2787.

[0007] This is because a stepped portion protruding inward along the inner peripheral surface on the upper end side and six substantially semi-circular cross-sectional tapered portions formed on the inner peripheral surface of the stepped portion at equal intervals. A cylindrical anchor body having a hole; a cross-section substantially corresponding to a semicircular tapered hole of the step portion, which is fitted into the step portion and is formed at both corners on the outer peripheral surface side of each divided piece. An annular support consisting of six divided pieces each having an arc-shaped tapered hole and a tapered hole having a substantially arc-shaped cross section on the inner peripheral surface side of each of the divided pieces; The seven fixing tapered holes formed by combining the three fixing pieces and the central tapered hole formed by the six divided pieces of the support member each include three divided pieces that are wedge-engaged. A wedge body; a fixing anchor steel wire attached to the upper and lower ends and inserted through the six fixing taper holes; Spacer locating the position of the drawn steel wire inserted through the drawing taper hole of the; a lid for covering the upper end of the anchor body; are composed of.

[0008] The earth anchor thus configured is
When removing the anchoring steel wire for anchoring, if the pulling-out steel wire fixed to the tapered hole at the center of the support is pulled out from the outside, the six split pieces fitted into the step of the anchor body will be At the same time as the supporting member collapses, the above-mentioned six fixing taper holes also collapse, so that the anchoring anchor steel wire fixed to these six fixing holes can be easily removed.

[0009]

However, the above-mentioned earth anchor still has a problem that workability is poor because a drawing machine or the like must be used when removing the anchor steel wire. In addition, since the above-mentioned earth anchor has as essential components a drawing steel wire and a wedge body for fixing the same in addition to the components for fixing the anchoring anchor steel wire, the number of parts is large, and the cost is high. However, there is a problem in that the structure is complicated and the workability and assemblability are poor because the structure is complicated.

An object of the present invention is to provide an earth anchor capable of easily and surely fixing and removing an anchor steel wire by a simple operation and capable of always maintaining a good fixing state.

Another object of the present invention is to provide an earth anchor which can reduce the number of parts and has good workability and assemblability.

[0012]

In order to achieve the above-mentioned object of the present invention, the earth anchor from which the anchor steel wire according to the present invention can be removed is formed on the outer peripheral surface located at the upper end side. A male screw portion 11 and an electric wire hole 12 projecting inward from an inner peripheral surface located at the lower end side and through which the electric wire 3 passes.
a and the internal thread 12b into which the external thread of the load-bearing body B is screwed
And an electric wire projecting inward from an inner peripheral surface portion located on the upper end side of the first step portion 12 and passing through the electric wire hole 12a of the first step portion 12 A substantially cylindrical anchor body 10 having a second step portion 13 having an electric wire hole 13a through which the second step portion 13 of the anchor body 10
And a donut-shaped maintenance body 20 made of a thermoplastic resin provided with an electric heating element 22 with an electric wire 23 and a second step of the maintenance body 20 and the anchor body 10 formed thinner than the outer peripheral surface. An annular insertion portion 31 having a diameter inserted into the step portion 13; a tapered hole 33 formed on the inner peripheral surface and expanding toward the upper end side; A substantially cylindrical sliding body 30 slidably housed in the anchor body 10, having a plurality of toothed grooves 34 arranged along the tapered surface and spaced apart along the tapered surface; , The tapered hole 33 of the sliding body 30
A wedge body 41 whose outer peripheral surface that is wedge-engaged with a plurality of anchor steel wires A forms a substantially inverted conical tapered surface, and is arranged at intervals along the outer peripheral edge of the wedge main body 41. A plurality of toothed grooves 42 formed along the tapered surface of the wedge main body 41 and corresponding to the plurality of toothed grooves 34 of the sliding body 30, and are protruded from the upper end of the wedge main body 41, and are formed on the inner peripheral surface. A wedge body 40 having a substantially annular protrusion 43 having a female screw portion 43a, and a female screw portion 51a into which the male screw portion 11 of the anchor main body 10 is screwed on the inner peripheral surface on the lower end side, A closed substantially cylindrical lid body 51;
A lid 50 having a bolt hole 52 penetrated through the center of the upper plate 51b, a fastening portion 53 projecting above the lid main body 51 and capable of engaging a tool, and the wedge 40 And a bolt 60 for screwing the wedge body 40 to the back surface of the upper plate 52 of the lid body 50 so that the wedge body 40 does not rattle. The ends of the plurality of anchor steel wires A to be inserted into the back are the sliding body 30 housed in the anchor main body 10 via the maintenance body 20 and the wedge body 40 pressed by the lid body 50. Of the anchor body 10 and the step 32 of the sliding body 30 by energizing the electric heating element 22 attached to the maintenance body 20. The interposed maintainer 20 is heated By, the sliding member 30
Is moved downward and away from the wedge body 40 so that the anchor steel wire can be removed.

The earth anchor according to the present invention, from which the anchor steel wire can be removed, is characterized in that the support body 20 is made of any one of polyamide MC nylon, polyacetal resin and polycarbonate resin. Features.

The earth anchor according to the present invention, from which the anchor steel wire can be removed, has a low elasticity between the lower surface of the head of the bolt 60 and the upper peripheral surface of the bolt hole 52 of the lid 50. Is characterized in that the buffer ring R is interposed.

According to the earth anchor of the present invention configured as described above, the ends of the plurality of anchor steel wires inserted into the back from the lower end of the anchor body are placed between the sliding body and the wedge body. After being sandwiched, the fixing can be easily and surely performed only by a simple operation of applying a tool such as a wrench to the tightening portion of the lid and rotating the fixing body, and the fixing state can always be maintained satisfactorily. In addition, the plurality of anchor steel wires fixed in this way can be connected to the second step portion of the anchor main body and the step of the sliding body only by a simple operation of energizing the electric heating element embedded in the maintenance body. The sliding body can be easily and reliably removed by thermally decomposing the maintenance body interposed between the sliding part and the wedge body.

[0016]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

The ground anchor of this embodiment is shown in FIG.
As shown in FIG. 3, the anchor body 10 includes a maintenance body 20, a slide body 30, a wedge body 40, a lid body 50, and a bolt 60.

The anchor main body 10 has a substantially cylindrical shape with both ends opened, and a male screw portion 11 to be screwed into a female screw portion 51a of the lid 50, which will be described later, is formed on the outer peripheral surface on the upper end side. The inner peripheral surface located at the lower end side has a first step portion 12 projecting inward along the inner peripheral surface,
A second step portion 13 which is arranged directly above the step portion 12 with a space therebetween and protrudes inward along the inner peripheral surface thereof is formed. The first step portion 12 has a wire hole 12a vertically penetrated through which a wire 23 connected to a maintenance member 20 described later is inserted, and a female screw portion formed with a male screw portion formed in the load bearing member B. The second step portion 13 is formed with a wire hole 13a communicating with the wire hole 12a. The inner diameter of the second step 13 is smaller than the inner diameter of the first step 12.

The maintenance body 20 is a doughnut-shaped molded body made of a thermoplastic resin, and has an electric heating element 22 embedded in a wall thereof. Thermoplastic resin
At room temperature, it is maintained in a very hard solid state like a metal, but has the property of being thermally decomposed and dissolved or vaporized when high heat is applied. Examples of such a resin include polyamide-based MC (monomer cast) nylon (trade name), polyacetal resin, and polycarbonate resin. The electric heating element 22 is a heating source that heats and thermally decomposes the maintenance body 20 made of a thermoplastic resin, and is molded and integrated with the thermoplastic resin during molding. Alternatively, the electric heating element 22 may be attached to the bottom surface of the maintenance body 20 and attached. This electric heating element 22
Is connected to an electric wire 23 for passing a current supplied from the external power supply to the power supply.

In this embodiment, insulating plates 24 are attached to the upper and lower surfaces of the support 20. This insulating plate 24
Is used to remove the anchor steel wire A by electrically insulating the electric heating element 22 from the upper surface of the second end portion 13 of the metal anchor body 10 and a step 32 of the sliding body 30 described later. When the electric heating element 22 is energized at the same time, it is intended to ensure safety from the danger of power waste and electric shock accident due to electric leakage. However, the insulating plate 24 is not always necessary. The reason is that in the initial stage of energization of the electric heating element 22, the maintenance element 20 itself is thermally decomposed while the electric heating element 22 is being decomposed.
And the upper surface of the second end 13 of the anchor body 10 and the sliding body 3
Since the contact with the step 32 of the zero is interrupted and the remainder of the maintenance body 20 which is not further thermally decomposed serves as a similar insulator, it is not necessary to apply the insulating plate 24, and the insulating plate 24 is merely used. It is used in case of a short circuit.

The sliding member 30 is slidably housed in the anchor body 10 and has a substantially cylindrical shape with both ends opened. An annular insertion portion 3 which is inserted into the second step portion 13 of FIG.
1 is formed, and a tapered hole 33 is formed in the inner peripheral surface of the sliding body 30 so as to increase in diameter from substantially the middle of the inner peripheral surface toward the upper end. Also, in this tapered hole 33,
A plurality of (ten in this embodiment, as shown in FIG. 2, ten) substantially semicircular toothed grooves 34 are formed at regular intervals along the hole edge and cut along the tapered surface. ing.

The wedge body 40 is formed in the tapered hole 3 of the sliding body 30.
3, a substantially inverted conical wedge main body 41 which is wedge-engaged via a plurality of anchor steel wires A, and is provided on the upper surface of the wedge main body 41,
A substantially annular projecting portion 43 having a female screw portion 43a on the inner peripheral surface. Further, on the outer peripheral surface of the wedge body 41, a plurality of (a plurality of (corresponding to) the plurality of toothed grooves 34 of the sliding body 30 which are arranged at equal intervals along the outer peripheral edge and cut along the tapered surface, respectively). In this embodiment, as shown in FIG. 2, ten) substantially semicircular toothed grooves 42 are formed.

The lid 50 covers the upper end of the anchor main body 10, and has a female screw portion 51a on the inner peripheral surface on the lower end side into which the male screw portion 11 of the anchor main body 10 is screwed. And a substantially hexagonal nut-shaped fastening portion 53 for projecting upward from the upper plate 51b of the lid body 51 and for applying a tool such as a wrench. . In the center of the upper plate 51b of the lid body 51, a bolt hole 52 through which a bolt 60 described later is inserted is formed to penetrate.

The bolt 60 is used to fix the wedge body 40 to the back surface of the upper plate 51b of the lid body 51 so that the wedge body 40 does not rattle. The wedge body 40 is screwed into the female screw portion 43a of the projection 43 through the inside of the portion 53 and the inside of the bolt hole 52.
A low-elasticity buffer ring R made of polyester, urethane rubber, or the like is interposed between the lower surface of the head of the bolt 60 and the upper peripheral surface of the bolt hole 52 of the lid 50. The buffer ring R is for preventing the wedge engagement between the sliding body 40 and the wedge body 40 from being loosened when the bolt 60 is screwed into the female screw portion 43a of the projection 43 of the wedge body 40. is there.

Each of the constituent members configured as described above includes:
It is used as a set of assemblies as shown in FIGS. Hereinafter, a method of assembling the components and a method of fixing the plurality of anchor steel wires A to the anchor will be described.

First, the maintenance body 20 is inserted into the anchor body 10 from the upper end thereof and the electric wire led out from the bottom surface thereof so that the maintenance body 20 is placed on the second step portion 13 of the anchor body 10. 23 is inserted into the electric wire hole 13a of the second step portion 13 and the electric wire hole 12a of the first step portion 12 while being sequentially inserted.

Next, the slide 30 is fitted into the anchor body 10 from the upper end thereof until the step 32 of the slide 30 comes into contact with the upper surface of the maintenance body 20. At this time, the insertion portion 31 of the slide body 30 is inserted over the support body 20 and the second step portion 13. Therefore, the maintenance body 20
Are the upper surface of the second step portion 13 of the anchor body 10 and the sliding body 3
The position is set between the stepped portion 32 of the sliding member 30 and the inner peripheral surface of the anchor body 10 and the outer peripheral surface of the insertion portion 31 of the sliding body 30.

Next, after a plurality of anchor steel wires A are fitted from the lower end of the anchor body 10 through the first step portion 12 and the second step portion 13 into the tapered hole 33 of the sliding body 30,
The ends of the plurality of anchor steel wires A are inserted into the plurality of toothed grooves 34 formed in the tapered hole 33, respectively.

Next, the wedge body 41 of the wedge body 40 is fitted into the tapered hole 33 of the sliding body 30. At this time, the teeth of the plurality of anchor steel wires A are interposed between the plurality of toothed grooves 34 of the tapered hole 33 and the plurality of toothed grooves 42 of the wedge body 41. The fitting grooves 34 and 42 are fitted while matching.

Next, the cover 50 is rotated by applying a tool such as a wrench to the outer peripheral surface of the fastening portion 53, so that the female screw portion 51a of the cover 50 is
Is attached by screwing in the male screw part 11 of FIG. For this reason, the projecting part 43 of the wedge body 40 is pressed downward by the upper plate 51b of the lid body 50, so that the wedge body 41 of the wedge body 40 strongly clamps the ends of the plurality of anchor steel wires A. While being fitted into the tapered hole 33 of the sliding body 30. As a result, the ends of the plurality of anchor steel wires A are firmly fixed by the wedge of the sliding body 30 and the wedge body 40. Further, the ends of the plurality of anchor steel wires A are more firmly fixed by a plurality of saw-like teeth projecting horizontally in the plurality of grooves 34 and 42.

Next, with the bolt 60 interposed between the low-elasticity buffer ring R and the tightening portion 5 of the lid 50,
3 and the projection 4 of the wedge body 40 through the bolt hole 52
By screwing into the female screw portion 43a, the projection 43 is fixed to the back surface of the upper plate 51b of the lid main body 51 so that the wedge body 40 does not rattle.

Thereafter, the synthetic resin pipe C previously inserted into the plurality of anchor steel wires A is fitted into the insertion portion 31 of the sliding body 30 from the lower end of the anchor main body 10 and the synthetic resin pipe C is inserted into the synthetic resin pipe C in advance. The inserted load-bearing body B is connected to the male screw portion formed at the tip thereof by the first step portion 12 of the anchor body 10.
It is attached by screwing into the female screw portion 12b formed in the above. At this time, between the outer peripheral surface on the distal end side of the synthetic resin tube C and the inner peripheral edge of the insertion portion 31 of the sliding body 30, the outer peripheral surface of the synthetic resin tube C, the inner peripheral edge of the first step portion 12 of the anchor body 10, and The seal member S is interposed between the inner peripheral edges of the load-bearing body B to prevent water or the like from entering from outside.

Next, a method of removing a plurality of anchor steel wires A from the anchor will be described with reference to FIGS.

First, when an electric heating element 22 embedded in the maintenance body 20 is energized from an external power source through an electric wire 23, the electric heating element 22 generates heat and the maintenance body 20 made of a thermoplastic resin is thermally decomposed. Begin to be. Maintainer 2
0 is thermally decomposed while being gradually diffused outward from a portion adjacent to the electric heating element 22, and is partially vaporized and partially melted and left in a liquid phase.

When the maintenance body 20 is in the liquid phase, the sliding body 30 presses the liquid phase maintenance body 20 with the tensile force applied to the plurality of anchor steel wires A while the second body of the anchor body 10 is pressed. The liquid phase maintainer 20 which moves to the step portion 13 and is simultaneously pressed is the electric wire hole 13 of the second step portion 13.
a (specifically, the wire hole 13a of the second step portion 13).
Through the gap between the inner peripheral surface of the wire and the outer peripheral surface of the electric wire 23),
It is pressed out and accumulated in a space 14 formed between the first step portion 12 and the second step portion 13.

That is, as shown in FIG. 4, the sliding body 30 is separated from the wedge body 40 fixed to the lid body 50 by the bolts 60, so that a plurality of anchor steel wires A are formed.
The wedge engagement between the sliding body 30 and the wedge body 40 is released.
Accordingly, the plurality of anchor steel wires A fixed by the wedge engagement between the sliding body 30 and the wedge body 40 are instantaneously pulled out of the anchor main body 10 into the synthetic resin pipe C by the tensile force. Become.

The plurality of anchor steel wires A drawn into the synthetic resin pipe C in this manner are in a very free state such that they can be pulled out from the outside of the anchor holes only by human power. A plurality of anchor steel wires A can be easily removed without using heavy equipment such as a hoist.

[0038]

As described in detail above, according to the earth anchor of the present invention, the ends of the plurality of anchor steel wires inserted into the back from the lower end of the anchor body are connected to the sliding body and the wedge body. After being sandwiched in between, the fixing can be easily and surely performed only by a simple operation of applying a tool such as a wrench to the fastening portion of the lid and rotating the fixing member, and the fixing state can always be maintained in a good state. In addition, the plurality of anchor steel wires fixed in this manner can be connected to the second step portion 13 of the anchor main body 10 and the sliding member only by a simple operation of energizing the electric heating element embedded in the maintenance member. By thermally decomposing the holding body interposed between the stepped portion 30 and the wedge body, the holding body is separated from the wedge body without using heavy equipment such as a pulling-out device or a hoist. It can be easily and reliably removed. Also,
ADVANTAGE OF THE INVENTION According to the earth anchor of this invention, since the number of parts is smaller than a conventional thing, and a structure is simple, workability and assemblability can be improved and manufacturing cost can be reduced. Further, according to the earth anchor of the present invention, since a plurality of anchor steel wires can be fixed using a single sliding body and a wedge body, it is very useful that the earth anchor can be downsized. Become something.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a half of an earth anchor according to an embodiment of the present invention, cut away.

FIG. 2 is a plan view showing a state in which a wedge body is fitted to a tapered hole of a sliding body.

FIG. 3 is a longitudinal sectional view showing a state in which ends of a plurality of anchor steel wires are fixed between the sliding body and the wedge body by engagement of these wedges.

FIG. 4 is a longitudinal sectional view showing a state in which the maintenance body is thermally decomposed by energization of the electric heating element, so that the engagement between the sliding body and the wedge body is released.

FIG. 5 is a longitudinal sectional view showing a state in which the wedge engagement between the sliding body and the wedge body is released.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Anchor main body, 11 ... Male thread part, 12 ... First step part, 12a ... Electric wire hole, 12b ... Female screw part, 13 ... Second step part, 13a ... Electric hole, 14 ... Space, 20 ... Maintenance body, 22
... Electric heating element, 23 ... Electric wire, 30 ... Sliding body, 31 ... Insertion section, 32 ... Stepped section, 33 ... Tapered hole, 34 ... Toothed groove, 4
0: wedge body, 41: wedge body, 42: toothed groove, 43: protrusion, 43a: female screw part, 50: lid body, 51: lid body, 5
1a: female screw portion, 51b: upper plate, 52: bolt hole, 53
... Tightening part, 60 ... bolt, A ... anchor steel wire, B ... load bearing, C ... synthetic resin pipe, R ... buffer ring.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-75807 (JP, A) JP-A-57-146827 (JP, A) JP-A-59-10614 (JP, A) JP-A-51- 130010 (JP, A) JP-A-56-67017 (JP, A) Table 9 9-512868 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02D 5/80

Claims (3)

(57) [Claims] A male screw portion formed on an outer peripheral surface portion located on an upper end side, an electric wire hole protruding inward on an inner peripheral surface located on a lower end side, and an electric wire hole through which an electric wire passes, and a load carrying capacity. And a female screw portion 12b into which the male screw portion of the body B is screwed.
A step portion 12 and an electric wire hole 13a projecting inward from an inner peripheral surface portion located at an upper end side of the first step portion 12 and passing an electric wire passing through the electric wire hole 12a of the first step portion 12. Cylindrical anchor body 10 having a second step 13 having
And placed on the second step 13 of the anchor body 10,
A donut-shaped maintenance member 20 made of a thermoplastic resin provided with an electric heating element 22 with an electric wire 23, and formed one step narrower than the outer peripheral surface, and inserted into the second step portion 13 of the maintenance member 20 and the anchor body 10; An annular insertion portion 31 having a diameter which is smaller than the diameter of the insertion portion 31, a tapered hole 33 formed on the inner peripheral surface and expanding toward the upper end side, and arranged on the tapered surface of the tapered hole 33 at intervals along the hole edge direction. A substantially cylindrical sliding body 30 slidably housed in the anchor body 10 and having a plurality of toothed grooves 34 formed along the tapered surface; and a taper of the sliding body 30. A plurality of anchor steel wires A
A wedge main body 41 whose outer peripheral surface to be wedge-engaged through a wedge body forms a substantially inverted conical tapered surface, and a tapered surface of the wedge main body 41 which is arranged at intervals along the outer peripheral edge of the wedge main body 41 And a plurality of toothed grooves 42 corresponding to the plurality of toothed grooves 34 of the sliding body 30 and the wedge body 41
A wedge body 40 having a substantially annular projection 43 having a female screw portion 43a on the inner peripheral surface thereof, and a male screw portion 11 of the anchor body 10 on an inner peripheral surface on the lower end side.
A substantially cylindrical lid body 51 having a female screw portion 51a into which the upper body is screwed, the upper end of which is closed, and an upper plate 51b of the lid body 51
A bolt hole 52 penetrated in the center of the cover body, a fastening portion 53 projecting above the lid main body 51 and capable of engaging a tool,
The wedge body 40 is screwed into the female thread portion 43a of the wedge body 40.
A bolt 60 for fixing to the back surface of the upper plate 52 of the lid 50 so as not to rattle. The plurality of ends of the plurality of anchor steel wires A inserted into the back from the lower end of the anchor body 10 The portion is fixed by the pinching force of wedge engagement between the sliding body 30 housed in the anchor main body 10 via the maintenance body 20 and the wedge body 40 pressed by the lid body 50. Is thermally decomposed by energizing the electric heating element 22 attached to the holding body 20 interposed between the second step 13 of the anchor body 10 and the step 32 of the sliding body 30. An earth anchor capable of removing an anchor steel wire, wherein the anchor steel wire can be removed by moving the sliding body 30 downward and separating from the wedge body 40. 2. The ground according to claim 1, wherein said support body is made of any one of polyamide MC nylon, polyacetal resin and polycarbonate resin. anchor. 3. The lower surface of the head of the bolt 60 and the lid 5
The earth anchor according to claim 1, wherein a low elasticity buffer ring (R) is interposed between the zero bolt hole (52) and the upper peripheral surface.