JP4729690B2 - Anchor removing apparatus by high frequency induction heating and method for removing the same - Google Patents

Description

  The present invention relates to an apparatus for removing a PC (pressed concrete) steel strand of an anchor in construction work and a method for removing the apparatus.

  2. Description of the Related Art Conventionally, in construction work such as earth retaining, a removable anchor that does not leave a tensile steel material such as unbonded PC (pressed concrete) steel stranded wire in the soil after construction is widely known.

  Patent Document 1 discloses a core removal removal method in which a plurality of unbonded PC steel stranded wires are bundled together. 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. Edges are cut by the drawn gaps to facilitate removal from the ground.

  In this method, a large-diameter removal space can be secured, so there is a merit that the fixing surface can be cut with a relatively small tensile force. However, since a large-diameter unbonded PC steel material is used, there is a problem that the material cost increases. .

  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 wrecker. PC steel stranded wire is pulled out and removed.

  In this method, 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 without using a certain large force. 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.

  As a solution to these problems, Patent Document 3 is an invention of a method and an apparatus capable of removing a PC steel twisted wire reliably and in a short time regardless of the mooring method with a load-bearing body. A liquid-tightly sealed negative electrode facing the PC steel stranded wire from which the sheath has been removed is provided on the embedded tip side, and after construction work, the electrolyte solution is circulated through the negative electrode, and a DC power source is connected to the PC steel stranded wire. The anode is connected to the cathode and the cathode is applied with a voltage, and the PC steel twisted wire is melted and cut to be able to be drawn.

  However, this method has the advantage that it can be removed reliably without restrictions on installation compared to the conventional technology, but requires a water tank for the electrolyte solution, a liquid feed pump, and a pipe for the liquid feed pipe. There was a problem that it was large and costly.

  Further, Patent Document 4 includes a hollow coil that surrounds the filament in a tubular shape at a cutting position of the wire that is a tensile member, and a high-frequency current is applied to the hollow high-frequency induction coil to thereby form an internal portion of the tensile member. That is, it was a device that heats and cuts the inside of the filament by eddy current.

  However, it was necessary to insert a high-frequency induction coil cylinder in advance at the cutting position of the filament. In this operation, one end of each filament must be connected to the load-bearing body, and then a hollow high-frequency induction coil must be inserted through the entire filament. That is, the other end of each filament must be open. This limits the work. When there are a plurality of load bearing bodies, the replacement and movement of the coil are restricted.

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) Japanese Patent Application No. 2005-180001 (2nd page, FIG. 1) Japanese Patent No. 3163207 (page 2, FIG. 1)

  This invention is made | formed in view of the said problem, and makes it a subject to provide the removal apparatus of the PC steel twisted wire which can construct the attachment of a high frequency induction coil reliably in a short time, and its removal method.

  In particular, it is possible to provide a structure in which a high-frequency induction coil can be easily replaced and moved even when the cutting position is corrected and moved once installed and the other end of each filament is closed.

  Further, the present invention provides a PC steel stranded wire removing device and a removing method that can be easily replaced and moved even if there are a plurality of load bearing bodies.

In order to solve the above-mentioned problems, the anchor removing device by high frequency induction heating according to the present invention fixes the end of the PC steel stranded wire to the embedded tip side of the unbonded PC steel stranded wire covered with a synthetic resin sheath with a crimping clip. A grounding body that has a connected load bearing body, embeds the load bearing body in a hole in the ground, injects a caking material into the hole to form an anchor fixing portion, and tensions the proximal end of the PC steel stranded wire on the ground side A device for removing PC steel stranded wire in construction work used as an anchor,
The PC steel stranded wire is composed of a single strip or a plurality of strips, and the load bearing body reliably forms a fixed connection by injection of the solidified material to the respective strips.
Prepare a planar coil that is insulated and coated with a hollow area of a predetermined shape as a coil core, wound into a single turn or multiple layers in a spiral shape and formed into a flat shape, and the plane is bendable,
The planar coil for induction heating with a high-frequency magnetic field while applying tension at a predetermined position to be cut at each linear line inserted and set in the linear groove or hole at the predetermined position from the outside. A high-frequency induction coil curved so as to be sandwiched;
A high-frequency current input terminal for applying a high-frequency current to the high-frequency induction coil from a high-frequency power supply device installed on the ground side through a twisted power supply line;
When the high-frequency induction coil is operated, the predetermined shape hollow region of the coil core portion, which is the portion with the highest magnetic flux density, includes each filament at the predetermined position to be cut and is disposed adjacent to it. And

Further, a high-frequency resonance current having a resonance frequency f ₀ (1 / 2π (Ls · Cs) ^1/2 ) determined from the inductance Ls of the high-frequency induction coil and the series capacitance Cs of the adjustment capacitor incorporated in the high-frequency power supply device is obtained. In a short time, the amount of heat flowing in the induction coil is maximized and the secondary induction current of the eddy current induced in the circumferential direction of each filament sandwiched between the planar coils is maximized. It is characterized by minimizing the breaking time of the strip.
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The anchor removing method by high frequency induction heating according to the present invention is such that a PC steel stranded wire end is fixed with a crimping clip to an embedded tip side of an unbonded PC steel stranded wire covered with a synthetic resin sheath, and a plurality of places connected thereto Load-bearing bodies installed in the ground, burying these load-bearing bodies in the holes in the ground, injecting the caking material into the holes to form anchor anchors, and tensioning the base end of the PC steel stranded wire on the ground side A method of removing PC steel stranded wire in construction work used as an earth anchor,
Inserting each predetermined wire into the wire groove or hole of each load-bearing body in order to securely connect each wire of the PC steel stranded wire to the load-bearing body;
In order to heat-cut the filament, a pre-insulated copper wire is wound into a single layer or multiple layers in a spiral shape with a predetermined shape hollow region as a coil core, and formed into a planar coil, and
Curving the planar coil, sandwiching a predetermined position to cut the filament near each load-bearing body, and setting as a high frequency induction coil;
Applying a high-frequency current to the high-frequency induction coil near each load-bearing body from a high-frequency power supply device installed on the ground side via a power supply line.

  When a high frequency induction coil is set at the cutting and heating position of each wire, if the coil is hollow or cylindrical, each wire whose one end is fixed to the load-bearing body is hollow or cylindrical from the other end. Since the coil is to be inserted, the other end of each wire must be open, so that the assembly of the coil set is limited accordingly.

  The planar coil of the present invention can be easily replaced and inserted arbitrarily even if the other end is closed.

  In particular, when it is desired to install a plurality of load bearing bodies in series, the planar bendable high frequency induction coil can improve the working efficiency.

  DESCRIPTION OF EMBODIMENTS Embodiments based on the drawings will be described in detail with respect to an anchor removing device by high frequency induction heating and a removing method thereof according to the present invention.

  FIG. 1 is a view showing a configuration of an unbonded PC steel stranded wire removing device by high frequency induction heating. In the figure, 1 shows the unbonded PC steel twisted wire which consists of single or multiple strips. 2 shows a load bearing body and fixes one end of the unbonded PC steel stranded wire 1.

  Reference numeral 3 denotes a retaining wall, and reference numeral 4 denotes a fixing bracket for fixing the retaining wall 3 by applying tension to the other end of the PC steel stranded wire 1. Reference numeral 5 denotes an anchor hole in the soil, and reference numeral 6 denotes a consolidated caking material poured into the anchor hole 5.

  Reference numeral 10 denotes a high frequency induction coil obtained by bending the bendable planar coil 10 'shown in FIG. As will be described later, the high frequency induction coil 10 is surrounded by the high frequency induction coil 10 so as to sandwich the unbonded PC steel stranded wire 1 composed of all the wires.

  11 is a lead wire (power supply line) for sending high-frequency power to the high-frequency induction coil 10, 12 is a high-frequency power supply device, and 13 is an AC power supply (commercial power supply).

  FIG. 2 is a view showing the appearance of the high-frequency induction coil 10 that is installed so as to surround and sandwich a plurality of unbonded PC steel stranded wires 1 together.

  Here, 2a indicates a wedge of the load bearing body 2.

  3 shows a cross-sectional view of the high-frequency induction coil 10, (a) is a cross-sectional view taken along the line AA in FIG. 2, (b) is a high-frequency induction coil installed so as to surround one unbonded PC steel stranded wire 1, c) shows a high-frequency induction coil installed so as to surround three unbonded PC steel stranded wires 1.

  FIG. 3A shows a case where the planar coil 10 ′ is curved in a circular shape so as to surround the four unbonded PC steel stranded wires 1.

  As shown in the figure, the unbonded PC steel stranded wire 1 indicates that the PC steel stranded wire 1a is covered with a synthetic resin sheath 1b.

  3 (a) and 3 (b) do not necessarily have to be curved in a circular shape, and it is only necessary that the unbonded PC steel stranded wire 1 enters the curved inner side of the planar coil 10 '.

  FIG. 3 (c) shows a case where the planar coil 10 ′ is bent in a triangular shape so as to surround the three unbonded PC steel stranded wires 1.

  FIGS. 4A and 4B are diagrams showing an example of a bendable planar coil 10 ′, where FIG. 4A is a plan view and FIG. 4B is a side view.

  This planar coil 10 'is formed as follows. That is, the insulation-coated copper wire is formed by winding only one layer in a spiral shape around its coil core portion 10'a (this shape is rectangular). In this description, a single-layer planar coil 10 'is shown, but a coil wound in a plurality of layers can be used in accordance with the thickness and number of PC steel stranded wires to be cut.

  In the figure, 10a is a coil copper wire, 10b is its insulation coating, 10c is a coil terminal, and 11 is a lead wire.

  In FIG. 4 (a), the coil copper wire 10a with insulation coating is illustrated as being wound at intervals, but actually, since it is insulated, it is wound closely without spacing. Put on.

  Further, since the central coil core portion 10'a is a region where the magnetic flux density is the highest, it is better to enlarge the rectangular hollow region as much as possible if the number of turns is the same.

  Further, the rectangular hollow region, that is, the coil core portion 10 ′ a has a number of strips if the long side of the rectangle surrounds the unbonded PC steel stranded wire 1 when the planar coil 10 ′ is curved. Since all the unbonded PC steel stranded wires 1 are heated at the same time, it is effective.

  The high frequency induction coil 10 can be resonated and heated in a short time so as to operate at the resonance frequency by the inductance Ls of the planar coil 10 ′ and the adjustment capacitor Cs in the power supply device 12.

  FIG. 5 shows an external view of the high-frequency induction coil 10 in which the planar coil 10 ′ is bent so that each wire of the unbonded PC steel stranded wire 1 is sandwiched.

  In this embodiment, the planar coil 10 'is curved in a circular shape or a cylindrical shape, but it may be curved in an arbitrary shape as long as all the filaments are surrounded.

  For example, it may be a triangular curve as shown in FIG.

  FIG. 6 shows an installation example of the high-frequency induction coil when the load-bearing body 2 has a plurality of two stages. This is an embodiment in which the anchor fixing portion is made sure.

  Reference numeral 21 denotes a first load-bearing body, and 22 denotes a second load-bearing body. The unbonded PC steel stranded wire 1 is composed of six wires, in which three wires are fixed to the second load-bearing body 22, and the remaining three wires are attached to the second load-bearing body 22. It passes without being fixed and is fixed to the first load-bearing body 21.

  21a is a first support pressure plate, 22a is a second support pressure plate, 21b is a first auxiliary pressure plate, and 22b is a second auxiliary pressure plate. In the second load-carrying body 22, three filaments are fixed by the second bearing plate 22a, and the other three filaments pass through the holes. In the first load-bearing body 21, the three striations that have passed therethrough are fixed by the first bearing plate 21a.

  In addition, 21c and 22c are center friction rods, and assist the load bearing body 2 being fixed to the ground by the poured binder agent.

  Reference numeral 23 denotes a first high-frequency induction coil, 24 denotes a second high-frequency induction coil, and 11 denotes each lead wire (power supply line).

  Reference numerals 25 and 26 denote crimping grips behind the first and second support plates 21a and 22a, respectively, and 27 and 28 denote first and second tip caps, respectively.

  Thus, when there are a plurality of load bearing bodies 2, by using the high-frequency induction coils 23 and 24 in the form in which the planar coil 10 ′ of the present invention is curved, the insertion becomes easy and the installation work of the removal device is reduced. It can be implemented very efficiently.

  FIG. 7 is a diagram showing details of a main part provided with a coil protection tube. In order to prevent damage to the heating coil when pulling out the casing for drilling when installing the anchor, the coil protection tube 29 is covered so as to cover the outer circumferences of the first and second load bearing bodies 21 and 22. The coil protective tube 29 has a plurality of opening windows 29a formed on the side surface of the cylinder so that the solidified material 6 (grout) poured into the anchor fixing portion flows into the coil mounting portion and is fixed. Use.

  FIG. 8 shows an embodiment of a coil protection tube, where (a) is a split type and (b) is a flexible material type. The split type shown in (a) is formed by being divided into a semi-cylindrical shape with an SS material or the like and covering the outer periphery of the load bearing body. The flexible material mold shown in (b) is a form made of a flexible material such as a poly material, provided with an opening 29b in a part of a cylindrical shape, and covering the outer periphery of the load-bearing body by expanding and covering the opening 29b. .

It is a figure which shows the structure of the removal apparatus of the unbonded PC steel twisted wire by high frequency induction heating. It is a figure which shows the external appearance of the high frequency induction coil installed so that the unbonded PC steel strand wire 1 may be inserted | pinched. 2 shows an installation cross section of the high frequency induction coil 10, (a) is a cross section taken along the line AA in FIG. 2, (b) is a high frequency induction coil installed so as to surround one unbonded PC steel stranded wire 1, and (c) is 3 The high frequency induction coil installed so that the unbonded PC steel twisted wire 1 of this book may be surrounded is shown. It is a figure which shows an example of the planar coil 10 'which can be bent freely, (a) is a plane front view, (b) shows a side view. The external view of the high frequency induction coil 10 which curved the planar coil and pinched each wire of the unbonded PC steel stranded wire 1 is shown, (a) is a front view, (b) is a side view. This is an installation example of the high-frequency induction coil 10 when the load-bearing body 2 has two or more stages. It is a figure which shows the detail of the principal part provided with the coil protection pipe | tube 29. FIG. An embodiment of the coil protection tube 29 is shown, in which (a) is a split type and (b) is a flexible material type.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Unbonded PC steel stranded wire 1a PC steel stranded wire 1b Synthetic resin sheath 2 Load-bearing body 2a Wedge 3 Mountain retaining wall 4 Fixing bracket 5 Anchor hole 6 Solidifying agent (grouting)
DESCRIPTION OF SYMBOLS 10 High frequency induction coil, induction coil, coil 10 'Planar coil 10'a Coil core part 10a Copper wire 10b Insulation coating 10c Coil terminal 10a Coil copper wire 10b Insulation coating 10c Coil terminal 11 Lead wire (power supply line)
12 High frequency power supply 13 AC power supply (commercial power supply)
21 first load bearing member 21a first bearing plate 21b first auxiliary bearing plate 21c central friction rod 22 second load bearing member 22a second bearing plate 22b second auxiliary bearing plate 22c central friction rod 23 first friction rod 23 Heating high-frequency induction coil 24 Second high-frequency induction heating coil 25 First crimping grip 26 Second crimping grip 27 First tip cap 28 Second tip cap 29a Open window 29 Coil protection tube 29a Open window 29b Open portion 31 PC steel stranded wire for first load bearing body 32 PC steel stranded wire for second load bearing body

Claims (3)

An unbonded PC steel stranded wire covered with a synthetic resin sheath is fixed to the distal end of the PC steel stranded wire with a crimping clip, and a load-bearing body connected to the end is embedded in the ground hole. A PC steel stranded wire removal device in construction work using a solidified material injected into a hole to form an anchor fixing portion, and the base end of the PC steel stranded wire is tensioned on the ground side,
The PC steel stranded wire is composed of a single strip or a plurality of strips, and the load bearing body reliably forms a fixed connection by injection of the solidified material to the respective strips.
Prepare a planar coil that is insulated and coated with a hollow area of a predetermined shape as a coil core, wound into a single turn or multiple layers in a spiral shape and formed into a flat shape, and the plane is bendable,
The planar coil for induction heating with a high-frequency magnetic field while applying tension at a predetermined position to be cut at each linear line inserted and set in the linear groove or hole at the predetermined position from the outside. A high-frequency induction coil curved so as to be sandwiched;
A high-frequency current input terminal for applying a high-frequency current to the high-frequency induction coil from a high-frequency power supply device installed on the ground side through a twisted power supply line;
When the high-frequency induction coil is operated, the predetermined shape hollow region of the coil core portion, which is the portion with the highest magnetic flux density, includes each filament at the predetermined position to be cut and is disposed adjacent to it. An anchor removal device by high frequency induction heating. A high frequency resonance current having a resonance frequency f ₀ (1 / 2π (Ls · Cs) ^1/2 ) determined from an inductance Ls of the high frequency induction coil and a series capacitance Cs of an adjustment capacitor incorporated in the high frequency power supply device is induced. In a short time, the amount of heat flowing in the direction of the wire is reduced by maximizing the secondary induced current of the eddy current induced in the circumferential direction of each wire sandwiched between the planar coils. 2. The anchor removing device by high frequency induction heating according to claim 1, wherein the breaking time is minimized. The end of the unbonded PC steel stranded wire covered with a synthetic resin sheath is fixed to the end of the PC steel stranded wire with a crimping clip, and equipped with load-bearing bodies installed at a plurality of locations connected thereto. PC steel stranded wire in construction work that is buried in the ground hole, injecting a caking material into the hole to form an anchor fixing part, and using the base end of the PC steel stranded wire as an earth anchor that tensions the ground side A method for removing
Inserting each predetermined wire into the wire groove or hole of each load-bearing body in order to securely connect each wire of the PC steel stranded wire to the load-bearing body;
In order to heat-cut the filament, a pre-insulated copper wire is wound into a single layer or multiple layers in a spiral shape with a predetermined shape hollow region as a coil core, and formed into a planar coil, and
Curving the planar coil, sandwiching a predetermined position to cut the filament near each load-bearing body, and setting as a high frequency induction coil;
Applying high-frequency current to the high-frequency induction coil in the vicinity of each load-bearing body from a high-frequency power supply device installed on the ground side via a power supply line. Removal method.

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