JP4359700B2 - Precast concrete pile core and method for removing reinforced concrete structure using the same - Google Patents

Description

  It is related with the removal method of the reinforced concrete structure using the precast concrete pile core material used for the reinforced concrete structure of the non-destructive site | part, and the pile core material.

  Conventionally, a mechanical destruction method such as a rock drill or a heavy machine for demolition has been used as a demolition method for a reinforced concrete structure. In particular, the retaining wall of the reinforced concrete structure, such as the start and arrival of shield machines built underground, is exposed to earth pressure and water pressure, and its structure is generally reinforced concrete connecting wall or H-shaped It was supposed to be strong by muddy water solidified walls, etc. solidified with soil cement using steel as the pile core material.

  If the retaining wall of such a reinforced concrete structure shaft can be cut and opened directly with a disk cutter of a shield machine, it is economical and safe. However, the earth retaining wall of the shaft was buried with reinforcing bars and steel as reinforcement, and could not be cut with a cutter of a shield machine.

  In order to solve these problems, there is known a retaining wall that uses a high-strength carbon fiber reinforced plastic as a reinforcing material in place of a reinforcing bar or steel, and can be cut with a shield machine using crushed limestone as a coarse aggregate. However, since the high-strength carbon fiber reinforced plastic as a reinforcing material is expensive, there is a problem in economy.

  Patent Document 1 discloses a method of dismantling a reinforced concrete structure for solving these problems, a reinforced concrete structure, a tunnel excavation method using a reinforcing material for a reinforced concrete structure, a shield machine, and a cutter bit of the shield machine. It is an invention related to a shaft having a possible temporary wall portion.

  The present invention provides a conductive hollow outer member having a reinforcing material provided at least at a site to be destroyed in a reinforced concrete structure, and a conductive hollow or solid shape that is loosely inserted into the outer member with a gap. The inner wall of the outer member or the outer wall of the inner member is anodically dissolved by applying a voltage between the outer member and the inner member with an electrolyte interposed between at least the outer member and the inner member. After fragile, the reinforced concrete structure is destroyed. However, in the present invention, there is a problem that it takes a long time to complete the dissolution and removal of the outer member and the inner member, which are pile core materials. In addition, this construction method requires construction equipment such as supply of an electrolyte solution, and has a problem that requires a schedule for the construction period.

Japanese Patent Laid-Open No. 2001-90473 (pages 2, 3 and 1)

  In order to solve the above-mentioned problem, the present invention has an object to provide a pile core material of a reinforced concrete structure at a non-destructive planned site that can be removed and replaced in a short time, and a method of removing the reinforced concrete structure using the pile core material. To do.

In order to solve the above-described problems, the precast concrete pile core material of the present invention is a rectangular concrete column made of high-strength concrete used as a pile core material of a reinforced concrete structure having a planned cutting / breaking location, and the rectangular concrete column is a reinforcement thereof. A plurality of unbonded PC steel wires anchored with prestressing as a material are embedded along the longitudinal direction, and a PC steel wire cutting device is provided by applying voltage to one mooring portion of the unbonded PC steel wire, and the other mooring portion The end of the PC steel wire protrudes by a predetermined length, and when the reinforced concrete structure breaks down, the PC steel wire is cut by applying a voltage to the PC steel wire cutting device. It is characterized in that it can be removed by pulling out a PC steel wire provided projecting a predetermined length from the end.

  The unbonded PC steel wire is either a PC steel stranded wire or a PC steel rod.

The PC steel wire cutting apparatus includes a carbon powder or carbon fiber resistance material (heating element) disposed so as to surround the PC steel stranded wire, and a metal provided in close contact with the outer periphery of the resistance material. It is composed of an electrode tube made of PC, two lead wires connected to a PC steel stranded wire and an electrode tube, and a DC power source that applies a voltage to the lead wire, and is electrically disconnected by the applied power. To do.

  Further, the reinforced concrete structure pile core material is provided with a bearing plate (anchor plate) and an anchor head for mooring a PC steel wire prestressed at both ends in the longitudinal direction, and a steel pipe or H It is characterized by having joints for connecting with the reinforcing material of the shape steel at both ends in the longitudinal direction.

The method for removing a reinforced concrete structure according to the present invention is a method for removing an underground reinforced concrete structure having a portion to be cut or destroyed.
The reinforcing material provided at the planned cutting / destruction site of the reinforced concrete structure is constructed of the precast concrete pile core material according to claim 1, and the PC steel wire material is connected to the PC steel wire from the DC power supply device via a lead wire at the scheduled cutting or destruction time. And cutting one end of the PC steel wire of the precast concrete pile core material by Joule heat generated in a resistance material (heating element) arranged to enclose the circumference of the PC steel wire by applying a voltage to the electrode tube, The PC steel wire material is extracted and removed from the other end, and the high-strength concrete for filling the voids of the pile core material from which the PC steel wire material has been removed is filled and cut directly with a shield machine.

  According to the precast concrete pile core material of the present invention, a pile core material of a reinforced concrete structure having a strength comparable to that of a conventional H-shaped steel or steel pipe pile is provided, and a PC steel wire that is a reinforcement material of the pile core material is provided at a necessary time. Can be cut and pulled out.

  Moreover, since the precast concrete pile core material is precast, it can be cut in a short time by mechanical cutting or electrical cutting that is fused by applying a voltage from a small-capacity DC power source. For this reason, the preparation of the facilities like the removal of the conventional pile core material, and a long removal period are not required.

  In addition, according to the method for removing a reinforced concrete structure of the present invention, a reinforced concrete earth retaining wall or the like in an underground tunnel that is excavated by a shield method or a propulsion method can be easily and quickly formed. It can be removed to make a retaining wall that can be excavated with a shield machine.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1: shows the precast concrete pile core material of this invention, (a) is a front view, (b) is a side view, (c) shows AA sectional drawing of (b). In addition, (a) and (b) show a partial cross section.

  In FIG. 1, the precast concrete pile core material 10 is comprised from the rectangular concrete pillar 1 and the joint part 6 provided in the upper and lower ends, and the inside of the rectangular concrete pillar 1 has unbonded PC steel stranded wire 2 as a reinforcing material. Are embedded. The unbonded PC steel stranded wire 2 may be a PC steel bar.

  The unbonded PC steel stranded wire 2 is held by a mooring portion provided with a PC steel wire rod cutting device 5 outside the through hole of the bearing plate 3 provided at the lower end of the rectangular concrete column 1. The anchor head 4 is tension-fixed by applying prestress outside the through hole of the bearing plate 3 provided at the upper end.

  The joint portion 6 is made of a steel plate having one end surrounding the rectangular concrete column 1 and has a bolt hole for connecting to an H-shaped steel or a steel pipe pile at the other end.

  From the anchor head 4, the end portion of the unbonded PC steel stranded wire 2 is projected for a predetermined length, and the PC steel stranded wire body 2 a (see FIG. 2) at the lower end of the rectangular concrete column 1 is caused by the PC steel wire cutting device 5. When it is cut, it is set as a gripping part when it is pulled out from the rectangular concrete column 1.

  As shown in FIG. 1 (b), in this embodiment, a rectangular concrete column 1 is embedded with five rows of unbonded PC steel stranded wires 2 as a reinforcing material.

  FIG.1 (c) shows the AA cross section of (a), and in this example, ten unbonded PC steel stranded wires 2 penetrate the inside of the rectangular concrete pillar 1.

  The PC steel wire cutting device 5 is provided with a cutting device for cutting a PC steel stranded wire by applying voltage or mechanical force inside, and as a mooring portion having a structure in which the tip of the PC steel stranded wire is moored by an anchor head (wedge) or the like. Yes.

  FIG. 2 is a schematic diagram of a PC steel wire cutting apparatus by applying a voltage. The PC steel wire cutting device 5 shown in FIG. 2 is a carbon powder or carbon fiber resistance material (heat generation) disposed so as to surround the PC steel stranded wire body 2a from which the sheath 2b of the unbonded PC steel stranded wire 2 is peeled off. Body) 5a, a metal electrode tube 5b provided in close contact with the outer periphery of the resistance member 5a, two lead wires 9b, 9a connected to the PC steel stranded wire body 2a and the electrode tube 5b, and a lead The DC power source 9 for applying a voltage to the wires 9a and 9b is housed in the mooring portion 5c, and the PC steel stranded wire body 2a is held by the mooring portion 5c by the anchor head 4.

  A PC steel stranded wire body 2a to which prestress is applied by applying a voltage between the lead wires 9a and 9b and heat-cutting the PC steel stranded wire body 2a by Joule heat generated in the resistor 5a. Is detached from the mooring portion 5c.

  Although not shown in the drawings, the cutting of the PC steel stranded wire body 2a is not limited to the application of voltage, and a mechanical cutting device (not shown) may be provided by pulling out mooring pins / bolts or pressing a cutting blade. .

  Since the precast concrete pile core material 10 of the present invention is manufactured by placing unbonded PC steel stranded wires in a formwork and pouring high-strength concrete and applying prestress, it can be factory-manufactured in advance and have a certain strength and quality. .

  FIG. 3 is a schematic view showing a retaining wall for starting and arriving against a shield machine using the precast concrete pile core material 10 of the present invention. FIG. 3 (a) is a front view of the pile core material built in the retaining wall. ) Is a cross-sectional view of the entrance portion.

  Based on FIG. 3, the removal method of the reinforced concrete structure of this invention is demonstrated.

  First, at the time of resisting excavation, the H-shaped steel 50 and the joint are arranged so that the precast concrete pile core material 10 of the present invention is disposed on the retaining wall portion to be destroyed (the position where the starting entrance wall of the shield machine is constructed in FIG. 3). The precast concrete pile core material 10 is built.

  In FIG. 3, the precast concrete pile core 10 having the lower end joined to the H-shaped steel 50 is built at the depth of the entrance wall 70 up to a position deeper than the flooring 80, and the H-shaped steel 50 is further installed on the upper part thereof. It is a joint.

  From the upper part of the precast concrete pile core material 10, unbonded PC steel stranded wire 2 protruded by a predetermined length, and lead wires 9a and 9b are extended from the lower part.

  A soil retaining wall is constructed by filling and solidifying the soil cement 60 in the hole in which the pile core material is built.

  After this, excavation is made, and the entrance wall 70 and the shield machine are installed. Immediately before starting the shield machine, a DC power source 9 (not shown) is connected to the lead wires 9a and 9b, and a voltage is applied to the PC steel wire cutting device 5 (see FIG. 1).

  The PC steel stranded wire main body 2a whose mooring at the lower end of the precast concrete pile core material 10 is opened by cutting is pulled out from the upper end of the precast concrete pile core material 10 and removed.

  A filler such as early-strength concrete is injected into the gap (seal) from which the PC steel stranded wire body 2a has been removed.

  The retaining wall from which the PC steel strand reinforcement has been removed is cut and propelled by a shield machine.

  In addition, this invention is applicable not only to the earth retaining wall of the start-and-arrival resistance of a shield machine but even a ground reinforced concrete structure.

The precast concrete pile core material of this invention is shown, (a) is a front view, (b) is a side view, (c) shows AA sectional drawing of (b). It is a schematic diagram of the PC steel wire cutting device by the application of a voltage. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the earth retaining wall of the shield machine start and arrival resistance using the precast concrete pile core material 10 of this invention, (a) is a front view of the pile core material built in the earth retaining wall, (b) is an entrance part. FIG.

Explanation of symbols

1 rectangular concrete pillar 2 unbonded PC steel stranded wire 2a PC steel stranded wire body 2b sheath 3 bearing plate (anchor plate)
4 Anchor head 5 PC steel wire cutting device 5a Resistance material (heating element)
5b Electrode tube 5c Mooring part 6 Joint part 9 DC power supply (battery)
9a Lead wire 9b Lead wire 10 Precast concrete pile core material 50 H-section steel 60 Soil cement 70 Entrance wall 80 Flooring

Claims (5)

A rectangular concrete column made of high-strength concrete used as a pile core material of a reinforced concrete structure having a planned cutting / breaking point,
The rectangular concrete column is formed by embedding a plurality of unbonded PC steel wires anchored with prestress as a reinforcing material in the longitudinal direction, and cutting the PC steel wire by applying a voltage to one of the anchoring portions of the unbonded PC steel wires. An apparatus is provided, and the end of the PC steel wire of the other mooring part is provided to protrude by a predetermined length,
When the reinforced concrete structure breaks down, the PC steel wire rod is cut by applying a voltage to the PC steel wire rod cutting device, thereby pulling out the PC steel wire projecting a predetermined length from the other end. Precast concrete pile core material that is configured to be removable.   2. The precast concrete pile core material according to claim 1, wherein the unbonded PC steel wire is either a PC steel twisted wire or a PC steel rod. The PC steel wire cutting device is made of a carbon powder or carbon fiber resistance material (heating element) arranged so as to surround the PC steel stranded wire, and a metal made in close contact with the outer periphery of the resistance material. It is composed of an electrode tube, a PC steel stranded wire and two lead wires connected to the electrode tube, and a DC power source for applying a voltage to the lead wire, and is electrically disconnected by the applied power. Item 2. A precast concrete pile core material according to item 1.   The reinforcing concrete structure pile core material is provided with a support plate (anchor plate) and an anchor head for mooring PC steel wires prestressed at both ends in the longitudinal direction, and further, a steel pipe or H-shaped steel to be built up and down The precast concrete pile core material according to claim 1, further comprising a joint portion connected to the reinforcing material at both ends in the longitudinal direction. A method of removing an underground reinforced concrete structure having a planned cutting or destruction site,
The reinforcing material provided at the planned cutting / destruction site of the reinforced concrete structure is constructed of the precast concrete pile core material according to claim 1, and the PC steel wire material is connected to the PC steel wire from the DC power supply device via a lead wire at the scheduled cutting or destruction time. And cutting one end of the PC steel wire of the precast concrete pile core material by Joule heat generated in a resistance material (heating element) arranged to enclose the circumference of the PC steel wire by applying a voltage to the electrode tube, Reinforcement characterized by extracting and removing PC steel wire from the other end, filling the void of the pile core material from which PC steel wire has been removed with high-strength concrete to develop strength, and cutting directly with a shield machine How to remove concrete structures.

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