JP3885124B2 - PC steel twisted wire removal device - Google Patents

Description

  The present invention relates to a PC (pressed concrete) steel strand removal device for a removable anchor in construction work.

  2. Description of the Related Art Conventionally, in construction work such as earth retaining, tensile steel materials such as PC (pressed concrete) steel stranded wire (hereinafter abbreviated as PC steel stranded wire) or load-resistant bodies are not left in the soil after construction. Removable anchors are widely known.

Patent Document 1 discloses a method and apparatus of a core removal method that is formed by binding a plurality of PC steel stranded wires. In the present invention, in order to solve the problem when a plurality of unbonded PC steel stranded wires are conventionally drawn and a space for cutting the fixed PC steel stranded wire is secured, an unbonded large-diameter steel material is used as a flexible spacer. Cover the anchoring part of the anchor placed in the cylinder with PC steel stranded wire from which multiple unbonding processes have been removed to form the fixing part, and then pull out the central large-diameter steel material after construction, and fix the fixed PC steel stranded wire. It is a method and apparatus for facilitating the removal from the ground by cutting the edge with the extracted gap.

This device has a merit that the fixing space can be cut with a relatively small tensile force because a larger removal space can be ensured than before, but since there is a large diameter unbonded PC steel material, there is a problem that the material cost increases. there were. In addition, there is a case where the edge cannot be cut reliably with a small force.

  Further, in Patent Document 2, an unbonded PC steel stranded wire is inserted into an anchor hole by making a U-turn with a load-bearing body, and filled with a grout material (a cemented material such as cement milk). PC steel stranded wire is fixed in the ground, both ends of unbonded PC steel stranded wire are tensioned and fixed under a predetermined load from outside the hole, and the removal type that supports the retaining wall and retaining wall by the tension and fixing force Anchors are described as prior art. In this unbonded PC steel stranded wire U-turn system, the ground fixing tool is removed after construction, and one end of the unbonded PC steel stranded wire is unbonded via a U-turn portion by pulling it with a jack or a tow. PC steel stranded wire is pulled out and removed.

In this method and apparatus, although the sheath tube is filled with lubricating oil, there is a problem that the friction coefficient at the U-turn portion of the PC steel stranded wire is high and cannot be extracted unless a certain amount of force is used. In addition, there is a problem that the U-turn portion is not twisted due to deformation such as twisting and cannot be pulled out.

Japanese Patent Laid-Open No. 9-41371 (2nd, 3rd page, 1st and 2nd figures) Japanese Patent Application No. 2002-97638 (2nd page, FIGS. 4 and 6)

The present invention has been made in view of the above problems, the mooring system (tension, compression) of the load carrying body regardless, to ensure the PC steel twisted wire is tensile material, and kill in a short time to remove device It is an issue to provide.

  In addition, it is possible to use only the PC steel twisted wire necessary to make the anchor of the required strength, while the construction method is limited to an even number of tensile steel wires because of the conventional U-turn. Therefore, it is an object to reduce the material cost and the construction cost by reliably removing the PC steel stranded wire.

In order to solve the above-mentioned problems, an apparatus for removing a PC steel stranded wire includes an uncurtain dong of an uncurtain dong provided with a load proof body on an embedded tip side of an unbonded type PC steel stranded wire covered with a synthetic resin sheath. In civil engineering work using an earth anchor that is buried in a hole, injecting a binder and forming an anchor fixing portion, and tensioning the base end of the PC steel stranded wire on the ground side,
A portion of the synthetic resin sheath on the embedded tip side of the PC steel twisted wire is removed over the entire circumferential direction, and a cylindrical metal negative electrode is provided to cover the negative electrode. While facing the PC steel stranded wire body in the synthetic resin sheath, the outer peripheral edges of both ends of the cylindrical metal negative electrode are fixed to the synthetic resin sheath with a liquid-tight sealant, and the lead wire of the negative electrode is embedded Sometimes extended to the ground side,
After civil engineering work, the positive electrode side is connected to the PC steel stranded wire body, a direct current is applied between the negative electrode and the positive electrode, and an electrolyte solution is supplied into the synthetic resin sheath of the PC steel stranded wire. Thus, the PC steel stranded wire body is corroded and cut in the vicinity of the negative electrode.

  According to this invention, since the negative electrode is provided on the unbonded type PC steel stranded wire, the structure is simple and the electrolytic corrosion portion can be formed at low cost. Further, since the uncurtain dong is embedded together with the lead wire connected to the negative electrode, the construction is easy.

In addition, an uncurtained PC steel stranded wire covered with a synthetic resin sheath embedded in an uncurtain dong having a load bearing body on the leading end side, the load bearing body is buried in a hole in the ground, and a solidified material is injected into the anchor. In civil engineering work using an earth anchor that forms a fixing part and tensions the base end of the PC steel stranded wire on the ground side,
The load-bearing body includes a connecting portion to which a mooring portion of a PC steel stranded wire, an electrolytic corrosion portion that penetrates an exposed PC steel stranded wire from which a sheath material has been removed, and a pipe and a lead wire that are filled and circulated with an electrolyte solution are connected The electrolytic corrosion portion is provided with a cylindrical negative electrode that covers the periphery of the PC steel stranded wire that penetrates, and an electrolytic corrosion chamber that is formed so that an electrolyte solution can be filled and circulated from the connection portion is provided. And
The negative electrode lead wire is extended to a position on the ground side when buried,
After civil engineering work, the positive electrode side is connected to the PC steel stranded wire body, a direct current is applied between the negative electrode and the positive electrode, and the electrolyte solution is supplied into a pipe for filling and circulating the electrolyte solution. Thus, the PC steel stranded wire body is corroded and cut in the vicinity of the negative electrode.

  According to this invention, an electrolytic corrosion part can be formed in a part of unbonded PC steel stranded wire. Further, since the sheath material and the negative electrode are sealed in a liquid-tight manner, the space between the PC steel stranded wire body and the negative electrode can be used as an electrolyte solution-filled space.

Moreover, according to this invention, since the electrolytic corrosion part of a PC steel stranded wire is provided in the inside of the load bearing body, the PC steel stranded wire can be cut and removed at the underground tip. In addition, efficient anodic dissolution can be performed by efficiently supplying and circulating the electrolyte solution and applying a voltage in the vicinity of the electrode through the lead wire.

  According to the present invention, the underground PC steel stranded wire can be cut and removed reliably in a short time at the time of removal of the earth anchor after civil engineering. For this reason, it is possible to prevent the problem of being left in the ground due to the conventional inability to pull out.

  Moreover, it is economical because the electrolytic corrosion portion can be formed at an end portion of the unbonded PC steel stranded wire or inside the load bearing body at a low cost. Furthermore, the construction period for anchor installation and removal is short, and the overall cost can be reduced.

  The conventional U-turn type removable anchor was limited to an even number of PC steel stranded wires, but according to the present invention, it is not limited to the U-turn type, and a PC steel stranded wire with a required load is used. Therefore, it can be an economical construction. Moreover, since it is not necessary to consider the friction between the PC steel stranded wire and the load-bearing body as in the U-turn system, the load-bearing body can be made of a material that can be cut other than metal.

The best mode for carrying out the invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view for explaining a PC steel stranded wire removing device of the present invention, in which (a) is a cross-sectional view of an electrolytic corrosion portion of an unbonded PC steel stranded wire, and (b) is a cross section of an unbonded PC steel stranded wire. FIG.

  An unbonded PC steel stranded wire 10 shown in FIG. 1A is a consolidated material in which the outer periphery of a PC steel stranded wire body 1 is covered with a synthetic resin sheath 2 and poured into an anchor hole in order to fix an uncurtain dong. (Gloud) and PC steel twisted wire main body 1 are made not to adhere.

  The electro-corrosion part 100 of the unbonded PC steel stranded wire of the present invention removes a part of the synthetic resin sheath 2 of the unbonded PC steel stranded wire 10 and provides the negative electrode tube 3 there, and both ends of the negative electrode tube 3. Further, the synthetic resin sheath 2 opposed to the PC steel twisted wire body 1 is adhered to the PC steel stranded wire body 1 which is made liquid-tight by bonding with a water-stopping material 4 and is removed by removing the synthetic resin sheath 2.

  The negative electrode tube 3 is provided with a lead wire 6a connected to the cathode of the DC power supply device 6 provided on the ground part, and further, an electrode facing the opposing PC steel stranded wire body inside the negative electrode tube 3 Providing the protrusion 3a is desirable for limiting and promoting the electrolytic corrosion range X.

  The PC steel stranded wire body 1 is connected to an anode of a DC power supply device 6 provided on the ground portion via a lead wire 6b.

  As shown in the sectional view of FIG. 1 (b), the unbonded PC steel stranded wire 10 has a gap between the synthetic resin sheath 2 and the PC steel stranded wire body 1 inside thereof, and anchors the electrolyte solution 5 from the ground. It can be filled up to the end of the uncurtain dong in the hole. Further, if the unbonded PC steel stranded wire 10 is a load-bearing body having a U-turn structure, the electrolyte solution 5 can be supplied from one end and can be circulated to be discharged to the opposite end. .

Here, the PC steel twisted wire removing device of the present invention will be described with reference to the schematic diagram of the PC steel twisted wire removing device shown in FIG.

  First, the uncurtain dong 45 is inserted into the anchor hole 40 excavated from the ground surface 50. In this embodiment, the uncurtain dong 45 is assembled by the unbonded PC steel stranded wire 10 being folded by the U-shaped groove 20a at the tip of the load bearing body 20A and being bound to the load bearing body 20A by the binding band 20b. An electrolytic corrosion portion 100 is provided in advance in a portion immediately after the 10 is folded back by the load-bearing body 20A, and the cathode lead wire 6a is extended from the ground and connected to the electrolytic corrosion portion 100.

  Next, a fixing material (groud) 41 is poured into the anchor hole 40 to fill the periphery of the uncurtain don 45 and form the anchor body fixing portion 46 fixed to the anchor hole 40. A portion not fixed by the caking material 41 becomes a free length portion 47.

After the consolidated material 41 is solidified, a structure 51 such as a mountain retaining wall is provided on the ground surface 50, and the unbonded PC steel stranded wire 10 is tensioned by the fixing bracket 52 to fix the structure 51 to the base of the fixing bracket 52.
As a result, construction work will proceed in the space anchored by the anchor.

  After the construction work, an electrolyte solution tank 5c is prepared on the ground, and a liquid feed pipe 5a connected to a liquid feed pump 5d is connected to one of the unbonded PC stranded wires 10, and a liquid discharge pipe 5b is connected to the other. The pump 5 d is driven to supply the electrolyte solution 5 into the synthetic resin sheath 2, and the electrolytic solution 100 provided at the tip of the uncurtain dong 45 is filled and circulated.

  Here, the DC power supply device 6 is prepared on the ground, the anode and the PC steel stranded wire body 1 fixed to the fixing metal fitting 52 are connected by the lead wire 6b, and the cathode lead wire 6a provided to extend to the ground is provided. Is connected to the cathode of the DC power supply device 6 to apply a DC voltage to the electrolytic corrosion portion 100.

  When a current flows between the negative electrode tube 3 of the electrolytic corrosion portion 100 and the PC steel stranded wire body 1 via the electrolyte solution 5, the PC steel stranded wire body 1 is anodically dissolved and cut.

  PC steel twisted wire body 1 cut off from the ground after confirming the cutting of PC steel twisted wire body 1 by energization of a predetermined amount of electricity or change in current, removing fixing bracket 52 and structure (mountain wall) 51 1 is removed.

  In the embodiment shown in FIG. 2, the cathode electrode tube 3 provided on the unbonded PC steel stranded wire 10 is provided behind the load-bearing body 20 </ b> A, but can also be provided inside the load-bearing body 20. .

  In the above-described embodiment, the PC steel stranded wire 10 is connected and fixed in a state of bypassing the load-bearing body 20 on the embedded tip side, and both ends thereof are led out to the ground side. The stranded wire may have one end connected and fixed to the load-bearing body 20 on the embedded tip side.

  Moreover, although said embodiment showed the form which supplies the electrolyte solution 5 from the terminal of the said PC steel twisted wire 10, supply of the electrolyte solution 5 was provided separately in the electrolyte supply pipe | tube, and the said negative electrode It is good also as a form performed in a PC steel stranded wire from the position of 3 vicinity.

  Further, the PC steel stranded wire 10 is fixed to the fixing bracket 52 as it is, and the so-called PC steel stranded wire tension material is fixed on the ground side by being tensioned and fixed by a surface fixing tool on the ground side. If the anode dissolution of the wire body 1 is performed, the PC steel stranded wire body 1 can be cut in a short time with a small amount of electricity.

  Next, a PC steel stranded wire removing device according to an embodiment provided with an electrolytic corrosion portion inside the load-bearing body will be described with reference to FIG. 3A and 3B are diagrams showing an embodiment of a PC steel stranded wire removing device, in which FIG. 3A is a cross-sectional view of a load-bearing body for electrolytic corrosion at a tip portion, and FIG. 3B is a cross-sectional view of a load-proof body for electrolytic corrosion at an intermediate portion. (C) is sectional drawing which shows the structure of the load-bearing body for electrolytic corrosion.

  3A includes a mooring portion 21 covered with a tip cover 25, an electroerosion portion 22 sealed with the mooring portion 21, and a connection portion 23 covering the back of the electroerosion portion 22. The unbonded PC steel stranded wire 10 is penetrated through the load-bearing body 20B for electrolytic corrosion, and is anchored and fixed to the tip of the mooring portion 21 with a locking metal fitting 10c, and the synthetic resin sheath is removed from the penetrating portion of the electrolytic corrosion portion 22. The PC steel stranded wire main body is exposed, and the unbonded PC steel stranded wire 10, the electrolyte solution feeding pipe 10 a, and the drainage pipe 5 b are connected to the electrolytic corrosion part 22 through the connection part 23.

  The load-carrying body for electric corrosion 20C in FIG. 3 (b) has a structure for use as an intermediate load-bearing body when a plurality of load-bearing bodies are provided in one anchor hole and a strong anchor fixing force is required. Is. As shown in the figure, it is composed of a mooring portion 24, an electrolytic corrosion portion 25, and a connection portion 26, but the basic structure and function are the same as those of the load-proof body 20B for electrolytic corrosion at the distal end portion. A PC steel stranded wire 10 extending through the body is provided with a through-hole, and a connection path between a liquid feeding pipe 5a and a drain pipe 5b extending from the electrolytic corrosion portion 25 to the load bearing body at the tip.

  FIG.3 (c) is sectional drawing which shows the structure of the load-bearing body 20B for electric corrosion (20C is also the same structure). The mooring portion 21 and the electrolytic corrosion portion 22, and the connection portion 23 and the electrolytic corrosion portion 22 are in close contact with each other with a connection screw (not shown) and are integrally assembled as a load-bearing body.

First, the PC steel stranded wire 10 arranged and penetrated so that the center of tension of the electric corrosion resistant load 20 has a center of tension at the center is the locking metal fitting 10c protruding from the front portion of the mooring portion 21. It is crimped and the tension load of the PC steel stranded wire is transmitted to the load bearing body 20.

  The electrolytic corrosion portion 22 includes an electrolytic corrosion chamber 22a that can be filled with an electrolyte solution and is provided with a cylindrical negative electrode 3 that surrounds the PC steel stranded wire 10 that penetrates the electrolytic corrosion portion 22. The liquid supply path 22c and the liquid discharge path 22b, which are the passages, are connected to each other, and are connected to the liquid supply hole 3c and the liquid discharge hole 23b of the rear connection portion 23 and extend to the ground. Through the supply of the electrolyte solution 5, the drainage liquid containing the anolyte can be discharged.

  A lead wire 6a extending to the ground is connected to the cylindrical negative electrode 3 so that a voltage can be applied from the ground.

  If the load-bearing body provided with this electrolytic corrosion portion is used, the unbonded PC steel stranded wire can be cut and used on the spot according to the anchor hole at the site. For this reason, it is not necessary to prepare an unbonded PC steel stranded wire in which a predetermined length of electrolytic corrosion portion is formed.

It is a schematic diagram explaining the removal apparatus of the PC steel twisted wire of this invention, (a) is sectional drawing of the electrolytic corrosion part of an unbonded PC steel twisted wire, (b) is sectional drawing of an unbonded PC steel twisted wire. It is a schematic diagram of the removal apparatus of PC steel twisted wire of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows one Embodiment of the removal apparatus of the PC steel twisted wire of this invention, (a) is sectional drawing of the load-bearing body for electrolytic corrosion of a front-end | tip part, (b) is sectional drawing of the load-proof body for electrolytic corrosion of an intermediate part, (C) is sectional drawing which shows the structure of the load-bearing body for electrolytic corrosion.

Explanation of symbols

1 PC steel stranded wire body
2 Synthetic resin sheath
3 Negative electrode tube (cylindrical negative electrode)
3a Electrode protrusion
4 Water stop material
5 Electrolyte solution
5a Liquid feed pipe (pipe)
5b Drainage pipe (pipe)
5c Electrolyte solution tank
5d liquid feed pump
6 DC power supply
6a, 6b Lead wire
10 Unbonded PC steel stranded wire
10c Locking bracket
20 Load-bearing body
20A, 20B, 20C
20a U-shaped groove
20b Cable tie
21, 24 Mooring section
22, 25 Electric corrosion part
22a electric dining room
22b Drainage path
22c Delivery path
23, 26 connection
23b Drainage hole
23c Liquid feed hole
40 Anchor hole
41 Solidified material (groud)
45 An Curtain Don
50 Ground
51 Structure (mountain wall)
52 Fixing bracket
100 electric corrosion part

Claims (2)

Unbonded type PC steel stranded wire covered with a synthetic resin sheath Embededdon of an uncurtain dong equipped with a load bearing body on the leading end side, embedded the load bearing body in a hole in the ground, and injected a solidified material to anchor anchoring part In civil engineering work using an earth anchor that tensions the base end of the PC steel stranded wire on the ground side,
A portion of the synthetic resin sheath on the embedded tip side of the PC steel twisted wire is removed over the entire circumferential direction, and a cylindrical metal negative electrode is provided to cover the negative electrode. While facing the PC steel stranded wire body in the synthetic resin sheath, the outer peripheral edges of both ends of the cylindrical metal negative electrode are fixed to the synthetic resin sheath with a liquid-tight sealant, and the lead wire of the negative electrode is embedded Sometimes extended to the ground side,
After civil engineering work, the positive electrode side is connected to the PC steel stranded wire body, a direct current is applied between the negative electrode and the positive electrode, and an electrolyte solution is supplied into the synthetic resin sheath of the PC steel stranded wire. Thus, the PC steel stranded wire removing device is characterized by corroding and cutting the PC steel stranded wire body in the vicinity of the negative electrode. Unbonded type PC steel stranded wire covered with a synthetic resin sheath Embededdon of an uncurtain dong equipped with a load bearing body on the leading end side, embedded the load bearing body in a hole in the ground, and injected a solidified material to anchor anchoring part In civil engineering work using an earth anchor that tensions the base end of the PC steel stranded wire on the ground side,
The load-bearing body includes a connecting portion to which a mooring portion of a PC steel stranded wire, an electrolytic corrosion portion that penetrates an exposed PC steel stranded wire from which a sheath material has been removed, and a pipe and a lead wire that are filled and circulated with an electrolyte solution are connected The electrolytic corrosion portion is provided with a cylindrical negative electrode that covers the periphery of the PC steel stranded wire that penetrates, and an electrolytic corrosion chamber that is formed so that an electrolyte solution can be filled and circulated from the connection portion is provided. And
The negative electrode lead wire is extended to a position on the ground side when buried,
After civil engineering work, the positive electrode side is connected to the PC steel stranded wire body, a direct current is applied between the negative electrode and the positive electrode, and the electrolyte solution is placed in a pipe filled and circulated with the electrolyte solution. A PC steel stranded wire removing device, wherein the PC steel stranded wire body is corroded and cut in the vicinity of the negative electrode by being supplied.

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