JP2019157475A - Water-stopping structure of tensile material - Google Patents

Abstract

To provide a water-stopping structure that can improve the water-stopping performance of a tensile material such as an elongate material (for example, a steel stranded wire or a steel bar) on which tension is applied in a ground anchor with a simple structure.SOLUTION: Adhesive (3: water-stopping material) is applied to a part of a tension material (1), a first sheath (2: made of polyethylene or nylon) covers a part of the region where the adhesive (3) is applied, the region where the first sheath (2) and the adhesive (3) are applied is covered with a second sheath (4: heat-shrinkable sheath), and both ends of the second sheath (4) are fastened by a strip material (5: fiber-containing tape) that is flexible but does not expand and contract.SELECTED DRAWING: Figure 1

Description

  The present invention relates to water stoppage of a tensile material such as a material (for example, a steel stranded wire or a steel bar) used in a ground anchor method, for example, on which a tensile force acts.

As a tensile material used in a ground anchor method for stabilizing the slope, a high-strength steel wire, for example, a PC steel wire formed by twisting several side wires around a core wire, is used. PC steel strands (multiple PC steel strands) are usually manufactured as bare wires. And in the fixing length part, the wire from the PC steel is fixed and fixed to the cast solidified material (concrete etc.), but in the free length part, the wire from the PC steel is not fixed and fixed to the solidifying material (unbonded) PC steel strand).
The unbonded PC steel wire is covered with a resin (for example, polyethylene) sheath (cladding tube) from the PC steel to separate the wire from the concrete and PC steel.
PC steel strands in which the bare wire portion (fixed length portion) that is not covered with the sheath and remains as bare wire and the covered portion (free length portion) covered with the sheath are also used in the ground anchor method It is well known as a PC steel strand (partial unbonded PC steel strand) (see, for example, Patent Document 1).

  For the above-mentioned PC steel strands, apply a water-stopping material etc. to the boundary between the sheath-covered part and the uncovered part (the end of the part not covered with the sheath), and cover with vinyl tape etc. Therefore, the inflow of drilling water and groundwater is blocked.

However, in the PC steel strand, a gap is generated between the core wire at the center in the radial direction and the side wire on the outer side in the radial direction, so there is a possibility that water may enter from the gap. There is also a risk that water may enter through the gap between the surface of the PC steel strand and the sheath.
In order to reduce such fear, there is a request to further improve the water stopping performance, but no technology that can meet such a request has been proposed yet.

JP 2001-146742 A

  The present invention has been proposed in view of the above-described problems of the prior art. For example, the water stopping performance of a tensile material such as a material (for example, a steel stranded wire or a steel bar) on which a tension is applied in a ground anchor, The purpose is to provide a water stop structure that can be improved by a simple structure.

The waterproof structure of the tensile material of the present invention is
An adhesive material (3: water stop material) is applied to a partial region of a tensile material (1: steel strand, steel bar, for example)
A first sheath (2: made of polyethylene or nylon: unbonded sheath) covers a part of the region to which the adhesive (3) is applied;
The region where the first sheath (2) and the adhesive (3) are applied is covered (covered) with a second sheath (4: heat-shrinkable sheath),
The second sheath (4: heat-shrinkable sheath) is characterized by being fastened by a strip material (5: fiber-containing tape) that is flexible but does not expand and contract.
Here, the tensile material (1) is a material on which tension acts (for example, a steel stranded wire, a steel bar), and the “material” includes a tendon restraint length of 3.0 m to 10 m and a tendon free length of 4.0 m or more. Length.
Further, when the both ends of the second sheath (4) are tightened with a strip material (5: tape containing fibers) that is flexible but does not expand and contract, it is preferable that the second sheath (4) is tightened to the extent that it is compressed. .
In the present invention, after tightening both ends of the second sheath (4) with a strip (5) that is flexible but does not expand and contract, the second sheath (4) and the strip that is flexible but does not expand and contract. The material (5) can also be coated (covered by wrapping a vinyl tape) with a synthetic resin member (for example, vinyl tape).

In this invention, the tension | tensile_strength material (1) is comprised by twisting together several steel wires, and when apply | coating an adhesive material (3: water stop material), it expands the distance between steel wires (what is called "" “Open line”) is preferred.
Alternatively, the tensile material (1) is formed by twisting a plurality of steel wires, and does not widen the distance between the steel wires when applying the adhesive (3: water stop material) ("opening"). Is not preferred).

  Further, the tensile material (1) is preferably a plurality of steel wires covered with an organic substance (for example, an adhesion type ECF strand 1A which is a steel strand pre-coated with epoxy coating). In that case, it is not necessary to widen the distance between the steel wires (so-called “opening”).

  According to the present invention having the above-described configuration, both ends of the second sheath (4: heat-shrinkable sheath) are made flexible by a strip material (5: fiber-containing tape) that does not expand and contract, for example, the second sheath The water stop performance is improved by tightening the sheath (4) to the extent that it is pressed.

  According to the inventor's experiment, both ends of the second sheath (4: heat-shrinkable sheath) are tightened to the extent that the second sheath (4) is pressed, for example, by the strip material (5: fiber-containing tape). In this case, it was confirmed that the water stop performance could be maintained with respect to a water pressure of 10 times or more as compared with the case where the strip was not tightened.

It is explanatory drawing of the water stop structure which concerns on embodiment of this invention. It is A2-A2 arrow sectional drawing of FIG. It is explanatory drawing which shows the free length part and fixing part before assembling the water stop structure of FIG. It is process drawing which shows 1 process of assembling the water stop structure of FIG. It is process drawing which shows the process following FIG. FIG. 6 is a process diagram illustrating a process following the process in FIG. 5. FIG. 7 is a process diagram illustrating a process following the process in FIG. 6. It is explanatory drawing of the experimental apparatus which tests the water stop performance of the water stop structure which concerns on embodiment.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, referring to FIGS. 1 and 2, a water stop structure according to an embodiment of the present invention will be described.
In FIG. 1, the water stop structure according to the embodiment of the present invention is indicated by the reference numeral 10 as a whole.
The tensile material 1 is a member on which tension acts, for example, in a ground anchor method, and is composed of a PC steel wire in which a plurality of steel wires (wires) are twisted together. In the present specification, a tensile material and a PC steel wire may be expressed by reference numeral 1.
In the PC steel stranded wire 1 (tensile material), the symbol B indicates a boundary. The boundary B corresponds to the position of the underground side end (right end in FIG. 3) of the first sheath 2 (cladding tube) in the state shown in FIG.
And in FIG. 1, the area | region shown by arrow S of the underground side (right side in FIG. 1) rather than the underground side edge part of FIG. This is a fixing length portion fixed and fixed to concrete or the like, and an area indicated by an arrow F on the ground side (left side in FIG. 1) from the underground side end (right end in FIG. 1) of the water stop structure 10 is a PC. The steel stranded wire 1 is a free length portion that is not fixed or fixed to concrete or the like.
The PC steel strand 1 of the free length portion F is covered by the first sheath 2, but the PC steel strand 1 of the fixing length portion S is not covered by the first sheath 2 and remains bare.
Here, the first sheath 2 is made of resin (for example, polyethylene or nylon).

As shown in FIG. 2, the PC steel stranded wire 1 is constituted by twisting several (for example, six) peripheral wires 1A around one central wire 1B.
In FIG. 1, the codes | symbols 4 and 5 have each shown the heat-shrinkable sheath 4 (2nd sheath) and the strip 5 (for example, fiber-containing tape).

In FIG. 1, the water stop structure 10 is comprised in the area | region covered with the 1st sheath 2 (cladding pipe) and the area | region of PC steel strand 1 which is not coat | covered with the 1st sheath 2. In FIG.
In FIG. 1, an adhesive 3 (water-stopping material) is provided in a region of a predetermined length from the boundary B of the PC steel strand 1 in the region on the right side of the boundary B (partial region on the right side of the boundary B in the tensile material) Is applied.

As the adhesive material 3 (water-stop material), for example, a rubber-based adhesive material can be used. At the time of application, the adhesive material 3 (water-stop material) is injected and filled at room temperature. However, the adhesive 3 (water-stop material) is not limited to a rubber-based adhesive, and a resin-based adhesive can also be used.
As shown in FIG. 2, an adhesive 3 (water-stopping material) is applied or filled around the PC steel stranded wire 1. When the adhesive is applied, the area around the central wire 1B of the PC steel wire 1B that is not covered with the first sheath 2 and between the peripheral wire 1A (the adhesive 3) is surely filled. Therefore, after the distance between the peripheral wires 1 </ b> A is expanded (so-called “open line”) using a dedicated tool, the adhesive 3 is filled. If the dedicated tool is restored manually from the opened state after the adhesive 3 is filled, the PC steel strand 1 returns to the state before the “opening” by the restoring force of the steel wire (wire).
If the "opening" operation is repeated for each peripheral wire 1A, the adhesive material 3 (water-stopping material) can be reliably injected and filled in the area around the central wire 1B and between the peripheral wires 1A. . Note that the “opening” operation is not limited to the case of using a dedicated tool, and all modes in which the distance between the peripheral wires 1A is widened (so-called “opening”) with the existing technology are possible. .

  In the water stop structure 10 shown in FIG. 1, a partial region of the PC stranded wire 1 coated with the adhesive 3 (a region on the right side in FIG. 1 from the boundary B and in the vicinity of the boundary B), and the one A part of the first sheath 2 covering the partial region (a part covering the vicinity of the boundary B in the first sheath 2) is replaced with a heat-shrinkable sheath 4 (second sheath, heat-shrinkable tube). ).

As will be described later with reference to FIG. 6, when covering with the heat-shrinkable sheath 4, the adhesive material 3 is applied, and the region of the stranded wire 1 and the PC steel covering the first sheath 2 are applied. A heat-shrinkable sheath 4 having a length necessary for covering the region including the end of the wire 1 is prepared, and the prepared heat-shrinkable sheath 4 (not shown in FIGS. 3 to 5) is first prepared in advance. It is made to loosely insert into the sheath 2.
Then, the heat-shrinkable sheath 4 is moved to the region side of the wire 1 from the PC steel to which the adhesive 3 is applied, and the terminal of the first sheath 2 (terminal near the boundary B) is covered. When the heat-shrinkable sheath 4 is heated in such a state, the heat-shrinkable sheath 4 is shrunk, and the region containing the adhesive 3 and the region including the end of the first sheath 2 are shrunk. Is covered.

As shown in FIG. 1, the heat shrinkable sheath 4 is in the vicinity of both ends so that the heat shrinkable sheath 4 is compressed, for example, by a strip 5 (for example, a fiber-containing tape) that is flexible but does not expand and contract. It is tightened.
The strip 5 is flexible but does not expand and contract. For example, the strip 5 is not limited to the fiber-filled tape as long as the heat-shrinkable sheath 4 can be tightened to the extent that it can be compressed. .
In order to prevent the strip 5 from peeling off after constricting the vicinity of both ends of the heat-shrinkable sheath 4 with the strip 5 (for example, fiber-containing tape), and to hide the strip 5 A vinyl tape 12 (synthetic resin member: covered tape) is wound to cover the heat-shrinkable sheath 4 and the strip material 5.

As will be described later, according to the inventor's experiment, the degree of improvement in water stoppage performance due to the structure in which both ends of the heat-shrinkable sheath 4 are fastened by the strip 5 is very large.
According to the inventor's experiment, when the heat-shrinkable sheath 4 is tightened to the extent that the heat-shrinkable sheath 4 is pressed, for example, by the strip 5 (fiber-containing tape) near the both ends of the heat-shrinkable sheath 4, It has been confirmed that the water stoppage performance can be maintained even when the working water pressure is 10 times or more compared to the case where the strip 5 is not tightened.
In the illustrated embodiment, the peripheral portion of the central wire 1B of the PC steel strand 1 and the region between the central wire 1B and the peripheral wire 1A are filled with the adhesive 3 (water-stopping material), and the adhesive 3 is filled. Since the PC steel strand 1 and the first sheath 2 are covered with the heat-shrinkable sheath 4 and tightened to such an extent that the heat-shrinkable sheath 4 is pressed by the strip 5, water pressure acts on the heat-shrinkable sheath 4. Even so, drilling water and groundwater do not enter the interior, and the water stop performance is improved.

As described above, when the adhesive 3 is applied to a predetermined portion of the PC steel wire 1, the wire 1 is expanded (opened) from the PC steel. However, even if the expansion is not performed, a certain adhesive penetration effect is obtained, and therefore it is possible not to perform the expansion (opening) in the illustrated embodiment.
Further, in the illustrated embodiment, a PC stranded wire (adhesive ECF strand) that has been pre-coated with an epoxy coating can also be used as the tensile material.
When the PC steel strand 1 is an adhesion type ECF strand, the adhesive 3 may be applied to the entire peripheral surface of the adhesion type ECF strand which is a tensile material. If the adhesion type ECF strand is used, since the epoxy coating is applied in advance, it is not necessary to inject the adhesive 3 into the peripheral portion of the central wire 1B or the region between the central wire 1B and the peripheral wire 1A. The expansion (opening) of the wire 1 from the PC steel is not necessary.

Next, the procedure for assembling the water stop structure 10 will be described with reference to FIGS.
FIG. 3 shows the tension member 1 in a state before the water stop structure 10 is assembled. The free length portion of the PC steel stranded wire 1 is covered with a first sheath 2.
In FIG. 3, a rust preventive material 14 is contained inside the first sheath 2. In order to simplify the illustration, the illustration of the rust preventive material 14 is omitted in the drawings other than FIGS. 2 and 3.

In the step shown in FIG. 4, the adhesive 3 (water-stopping material) is applied to the region near the boundary B in the fixing length portion S of the PC steel strand 1 (fixing length portion).
Although not explicitly shown in FIG. 4, as described above, the adhesive application festival fills the adhesive 3 by expanding (opening) the distance between the peripheral wires 1 </ b> A (FIG. 3).

In FIG. 4, the position of the end portion of the first sheath 2 in the axial direction (left-right direction in FIGS. 3 to 7) coincides with the boundary B. However, in the step shown in FIG. By moving in the direction, the end of the first sheath 2 is located in the region where the adhesive 3 is applied beyond the boundary B.
In the step shown in FIG. 6, the region near the end of the first sheath 2 moved in the step of FIG. 5 and the region where the adhesive material 3 of the PC steel wire 1 is applied are formed with the heat-shrinkable sheath 4. Cover.
As described above, although not clearly shown in order to cover with the heat-shrinkable sheath 4, the heat-shrinkable sheath 4 is preliminarily inserted into the first sheath 2 and shown in FIG. The heat-shrinkable sheath 4 is moved so as to be in a state. The heat-shrinkable sheath 4 is moved to the state shown in FIG. 6, and the region near the end of the first sheath 2 and the region where the adhesive material 3 of the PC steel strand 1 is applied (with the heat-shrinkable sheath 4). When surrounded, heat-shrinkable sheath 4 is contracted by heating.

In the step shown in FIG. 7, the vicinity of both ends of the heat-shrinkable sheath 4 is tightened with the strip material 5 (fiber-containing tape). As described above, the strip 5 has a property of being flexible but not expanding and contracting, and is tightened to such an extent that the heat-shrinkable sheath 4 is compressed, for example.
In the water stop structure 10 according to the illustrated embodiment, the vicinity of both ends of the heat-shrinkable sheath 4 is fastened with the strip material 5, and then the vinyl tape 12 is wound around the heat-shrinkable sheath 4 and the strip material 5 to cover them. .

[Experimental example]
Next, an experimental apparatus 20 in which the inventor has experimented with the water stopping ability of the PC steel strand 1 will be described with reference to FIG. Using the experimental apparatus 20 shown in FIG. 8, the inventor experimented with the water stop structure 10 effect described with reference to FIGS. 1 to 7.
The experimental device 20 includes a pressurizing device 21 that pressurizes air, and discharges the pressurized air P through the pipe 22 to the high-pressure water feeding device 23. The high-pressure water supply device 23 introduces water from a water supply source (not shown) via the water hose connection portion 23A, and the water is pressurized by pressurized air pressurized by the pressurizing device 21, and is supplied from the supply port 23B. High pressure water W is discharged to the test body 30. Reference numeral 24 denotes an air bleeding device.

The test body 30 has the same configuration as the water blocking structure 10 described with reference to FIGS. In FIG. 8, the PC steel strand 1 on the right side of the test body 30 corresponds to a free length portion and is covered with the first sheath 2. On the other hand, the left portion of the test body 30 corresponds to the fixing length portion and is not covered with the first sheath 2.
As described with reference to FIGS. 1 to 7, the heat-shrinkable sheath 4 covers a region including the vicinity of the boundary B.
The vicinity of both ends of the heat-shrinkable sheath 4 is fastened by a strip 5 (fiber-containing tape). In addition, in order to prevent complication of drawing, illustration of the strip 5 is abbreviate | omitted in FIG.

In the experiment, when the high-pressure water W is discharged from the high-pressure water feeding device 23, the high-pressure water W passes through the earth and sand and rubble filling portion 25 assuming the ground from the left side of FIG. And it flows toward the area | region corresponded to the part which coat | covered the heat-shrinkable sheath 4 and the free length part which coat | covered the 1st sheath 2 through the area | region equivalent to the fixing length part of the wire 1 from PC steel.
In the inventor's experiment, in the test body 30, the presence or absence of the strip 5 (fiber-containing tape) that is tightened to such an extent that the heat-shrinkable sheath 4 is pressed, the PC steel strand 1 when the adhesive 3 (FIG. 4) is applied. The conditions such as the presence or absence of the open line were changed, and it was confirmed whether or not the high-pressure water W was passed through the free length portion.
In the inventor's experiment, the water pressure for passing water to the free length portion was higher in the case where the line was opened than in the case where the line was not opened. And when the water stop mechanism 10 demonstrated in FIGS. 1-7 is employ | adopted, in all other water stop structures, a water pressure far higher than the water pressure which water-passes to a free length part acts. However, it was confirmed that water does not flow to the free-length part.

It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.
For example, although FIG. 1 to FIG. 7 show a PC stranded wire as the tensile material, the illustrated embodiment can be applied to other tensile materials such as a steel bar.

1 ... Stranded PC steel 1 (tensile material)
DESCRIPTION OF SYMBOLS 1A ... Adhesion type ECF strand 2 ... 1st sheath 3 ... Adhesive material (water-proof material)
4 ... Second sheath (heat-shrinkable sheath)
5 ... Strip material (tape with fiber)
10 ... Water stop structure

Claims (3)

Adhesive is applied to a part of the tensile material,
The first sheath covers a part of the area where the adhesive is applied;
The first sheath and the region where the adhesive is applied are covered with a second sheath;
A waterproof structure for a tensile material, characterized in that it is clamped by a strip material that is flexible but does not expand and contract on the second sheath.   The waterproof structure according to claim 1, wherein the tensile material is formed by twisting a plurality of steel wires, and the distance between the steel wires is widened when the adhesive is applied.   The waterproof structure according to claim 1, wherein the tensile material is formed by twisting a plurality of steel wires, and the distance between the steel wires is not expanded when the adhesive is applied.

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