JP2020099918A - Steel-concrete composite component cutting method and cutting device - Google Patents

Abstract

To make it possible to cut a steel-concrete composite component comprising a steel material such as a steel plate or the like and lining concrete with good efficiency when dismantling a steel chimney.SOLUTION: Laser beam L having a long focal distance of 500 mm or more is so radiated as to be in focus in vicinity of a surface of a composite component 1 of a steel material 3 and concrete 2, and an assist gas G containing oxygen is so injected to a part of the composite component 1 to be cut with laser beam L as to be coaxial with laser beam L. The composite component 1 is cut by heat energy of laser beam L and combustion heat of iron contained in the steel material 3 by the assist gas G. Further, a molten material, which is generated by cutting, is removed by a gas.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for cutting a steel-concrete composite member and a cutting device, and in particular, various structures integrally constructed of steel materials such as steel plates and concrete by utilizing thermal energy of laser light and combustion heat of iron. The present invention relates to a cutting method and a cutting device for efficiently cutting a steel-concrete composite member for disassembling.

Conventionally, various structures and bridges constructed by using reinforced concrete or unreinforced concrete and shaped steel, steel plates, etc. (hereinafter referred to as steel-concrete composite members) for structural or application purposes. , Dams, various power plant facilities, radioactive material (RI) handling and storage facilities, reprocessing plants, nuclear fuel storage facilities, accelerator facilities, and various container structures and internal structures of these facilities. These facilities, buildings, structures, structures, etc. (hereinafter referred to as structures, etc.) will be dismantled by rebuilding, renewing, etc. after the service period and useful life have passed.

The dismantling work of these structures and the like is usually mechanically sequentially cut, and disassembled through a process of carrying out the small-sized members. For example, as a 100m-class chimney of a thermal power plant, there is a chimney having a chimney tube body in which a lining material is sprayed on the inside of a steel plate. When dismantling the chimney, a method of dismantling the chimney cylinder from the upper part while using a crane or the like to unload the chimney cylinder into slices on the ground using an appropriate mechanical cutting method is adopted.

Conventional mechanical cutting methods include the following methods.
(1) Non-contact cutting method As a non-contact cutting method, there is a cutting method using sandblast, abrasive water jet, or the like. Sandblasting and abrasive waterjet are methods that continuously grind from the surface to the deep inside of structures, etc. With sandblasting, concrete is easy to grind, but steel is difficult to grind. Abrasive water jets can grind both, but the equipment is expensive and the cutting speed is slow. Further, since grinding particles such as sand and abrasive particles are consumable materials, and a larger amount of grinding particles than the grinding amount is required, the amount of waste after use becomes enormous.
(2) Contact cutting method As a contact cutting method, there is a cutting method using a band saw, a grinder, a diamond saw or the like. With a band saw or grinder, the thickness of the target material is ground from the surface. Band saws, grinding belts for grinders, and grinding discs are consumable parts and become a large amount of waste after use. A diamond saw can easily cut reinforced concrete materials, etc., but in the case of a disk blade, the thickness of the material to be cut is limited, and in the case of a wire blade, it is difficult to control the tension of the wire blade when cutting a steel plate concrete composite member. ..
(3) Laser cutting method In the cutting method using laser light, the cutting of the steel material was performed at a practical level, but the cutting of the concrete material was performed at an experimental level (Patent Document 1, Patent). Reference 2, Patent Reference 3). Further, the cutting of the steel-concrete composite member has not been performed because the mechanism of cutting (destruction) is different. If it becomes possible to cut the steel-concrete composite member using laser light, it will be an effective cutting method in place of (1) and (2) described above.

JP-A-4-319087 JP-A-5-131286 JP, 2007-230230, A

The invention disclosed in Patent Document 1 discloses an angle of a gas jet nozzle and a depth of an intersection point with a laser beam in order to improve escape of molten concrete (molten dross) produced when a concrete mass is irradiated with the laser beam. It is an invention that appropriately sets the height. Further, in the invention disclosed in Patent Document 2, in order to prevent re-solidification of the molten dross, the assist gas nozzle is independent of the laser light nozzle, and the nozzle angle is appropriately set to efficiently melt the dross. It is an invention designed to blow away. The invention disclosed in Patent Document 3 is an invention that enables concrete to be cut by a low-power laser by crushing and removing the re-solidified dross.

In the inventions disclosed in Patent Documents 1 to 3, since the cutting site of the concrete irradiated with the laser beam is at a relatively low temperature, the molten dross is not removed and remains in the cutting groove or the like to be solidified again. It is in.

Therefore, the object of the present invention is to solve the problems of the above-mentioned conventional techniques, and when the steel-concrete composite member is irradiated with laser light, in addition to the controlled high-temperature laser light, the combustion of the steel material in the high temperature state is performed. (Oxidation reaction) To provide a cutting method and a cutting device for a steel-concrete composite member, in which the dross at the cutting location is blown off in a molten state by using heat, and the steel-concrete composite member can be efficiently cut. is there.

In order to achieve the above object, the present invention irradiates a laser beam having a long focal length so as to focus in the vicinity of the surface of a composite member of steel and concrete, and makes coaxial with the laser beam to generate oxygen. Injecting a gas containing gas into the composite member at a cutting point by the laser light, cutting the composite member by thermal energy of the laser light and heat of combustion of iron contained in the steel material by the gas, and generated by cutting. It is characterized in that the melt is removed by the gas.

In this cutting method, it is preferable that the focal length of the laser beam on the focusing side is 500 mm or more.

In addition, the concrete becomes a low-viscosity melt that is generated by continuous decarbonation explosion caused by contained carbonate and steam explosion caused by crystal water and contained water, and is removed by the gas. It is preferable.

Further, it is preferable that the surface of the composite member is irradiated with the laser light such that the distance between the tip of the nozzle and the surface of the composite member is substantially equal to the inner diameter of the nozzle of the laser head.

As an invention of a cutting device, a laser oscillator and a laser beam which is guided from the laser oscillator through an optical fiber and is irradiated with a laser beam having a long focal length so as to focus near the surface of a composite member of steel and concrete A laser head, a gas supply device for supplying a gas containing oxygen to a nozzle of the laser head, and a nozzle tip of the laser head are movable so as to be positioned and adjusted near the surface of the composite member. And a positioning drive mechanism for supporting the same.

In this apparatus, it is preferable that the focal length of the laser beam on the condensing side is 500 mm or more.

Further, it is preferable that the positioning drive mechanism includes an access rail facing the composite member, and a traverse rail capable of moving the laser head along the extension direction of the surface of the composite member.

Further, it is preferable that the positioning drive mechanism is operated so that the inner diameter of the nozzle of the laser head and the distance between the tip of the nozzle and the surface of the composite member are substantially equal.

1 is a sectional view of an apparatus configuration showing a partial section of the configuration of an embodiment of a cutting apparatus for a steel-concrete composite member of the present invention. The partial expanded sectional view which showed the structure of the nozzle of the cutting device shown in FIG. Sectional drawing which showed the example of the steel concrete composite member used as the cutting object of the cutting device of this invention. The state explanatory view which showed typically the cutting state of the structure by the cutting device of this invention.

Hereinafter, the configuration of a cutting device for realizing the method for cutting a steel-concrete composite member of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 shows a state where a part of the steel-concrete composite member 1 is cut by a cutting device 10 for a steel-concrete composite member of the present invention. The cutting device 10 includes a laser oscillator 11, a laser head 20 that irradiates the steel-concrete composite member 1 with a laser beam L from the laser oscillator 11, a positioning drive mechanism 30 that movably supports the laser head 20, and a laser head 20. And a gas supply device 40 for supplying the assist gas G to the nozzle 23.

The laser oscillator 11 is a known oscillator capable of oscillating a continuous wave (CW) laser having an output of about 10 kW in the present embodiment, and the laser oscillator 11 and the oscillator cooling unit 12 are operated by a power supply device 13.

In this embodiment, the laser head 20 is an elongated tubular body having a nozzle 23 on the lower end side. 1 and 2, the vertical installation state is shown for the sake of explanation. Since the present invention has a structure in which the laser head 20 moves to cut the steel-concrete composite member 1 (hereinafter, the steel-concrete composite member is referred to as the composite member 1), the laser head 20 is not irradiated with the laser light L. The nozzle 23 is supported by the positioning drive mechanism 30 so that the nozzle 23 is not displaced even when receiving a reaction force.

The laser light L is guided from the laser oscillator 11 to the upper end of the laser head 20 via the optical fiber 14. A collimator lens 21 made of a plano-convex lens and a condenser lens 22 made of a similar plano-convex lens with a predetermined optical path length are arranged on the optical path of the laser light L in the laser head 20. The laser light L guided into the laser head 20 from the optical fiber 14 is collimated into parallel light by the collimator lens 21 and is condensed by the condenser lens 22. The focal length of the laser light L in the laser head 20 is set to 500 mm in this embodiment. The shape of the nozzle 23 at the lower end of the laser head 20 is set to a conical shape having a nozzle diameter φ (FIG. 2) that does not interfere with the laser light L having this long focal length. A protective glass 24 is mounted above the nozzle 23 in the laser head 20 to block the influence of the pressure fluctuation of the assist gas G in the nozzle 23 on the optical system.

An assist gas supply port 25 is formed on the side surface of the nozzle 23. From this supply port 25, the oxygen gas as the assist gas G supplied from the gas supply device 40 is supplied into the nozzle 23 in a medium-high pressure (P=15 kPa) state. The assist gas G supplied into the nozzle 23 is jetted from the nozzle 23 toward the composite member 1 coaxially with the laser light L, and can blow away the melt generated at the cut portion.

The gas supply device 40 has a well-known equipment configuration, and in the present embodiment, an oxygen cylinder 41 and a regulator 42 that adjusts the supply pressure of oxygen gas are provided. In the present invention, as the assist gas G, a gas containing oxygen such as air can be used in addition to the oxygen gas.

As shown in FIG. 1, the positioning drive mechanism 30 that supports the laser head 20 includes an access rail 31 that faces the surface of the concrete 2 of the composite member 1 and a traverse rail 32 that is orthogonal to the access rail 31. The laser head 20 can move (run) in independent directions by using these two rails 31 and 32 as guides. A known linear slider 33 is used as a drive mechanism for the access rail 31. Further, the traverse rail 32 is set in a linear shape or a curved shape according to the shape of the composite member 1, but a slider capable of smoothly following the rail is used for any shape rail. In order to detect the approach distance between the nozzle tip 23a of the laser head 20 and the composite member 1, a position detection sensor 35 is attached to the outer surface of the laser head 20 in this embodiment. The distance measurement data from the position detection sensor 35 is sent to the control unit 36 that controls the operation of the drive mechanism. A position detection sensor 37 mounted on the slider 34 is used to detect the position of the laser head 20 on the traverse rail 32. Based on the position information from these position detection sensors 35, 37, the distance between the nozzle tip 23a of the laser head 20 and the composite member 1 can be adjusted, and the operation (running) of the laser head 20 during cutting work can be performed with high accuracy. ..

FIG. 2 shows an enlarged view of the vicinity of the nozzle 23 of the laser head 20 and the composite member 1. The nozzle diameter φ of the laser head 20 is set to 2 mm in this embodiment. The distance S (standoff distance) between the nozzle tip 23a and the surface of the composite member 1 is also set to about 2 mm (±0.1 mm). A laser beam dump 8 is arranged on the back surface of the composite member 1 on the steel plate 3 side with a predetermined distance from the steel plate 3. The laser beam L that has passed through the composite member 1 is safely absorbed and dissipated by the laser beam dump 8.

As shown in the same figure, the laser beam L of the present invention converges at a spot diameter of about 0.8 mm so that the vicinity of the surface of the concrete 2 of the composite member 1 becomes the focal position, but the long focal length (f= Since it is set to 500 mm), a sufficient depth of focus can be secured, and the thick composite member 1 can be cut. At an experimental level, in the laser head 20 having this configuration, a composite member having a concrete member thickness of 10 cm and a steel plate thickness of 1 cm by a laser beam L having an output of about 10 kW and a steel member having a height of 10 cm simulating a member reinforcing rib are used. It was confirmed that when the test specimen was cut, it could be cut at a cutting speed of about 3 to 10 cm/min.

Here, the cutting operation of the composite member by the laser light of the cutting device of the present invention and the cutting action of the composite member will be described.
In order to cut a steel-concrete composite member, first, a laser beam controlled with high precision is concentrated and applied to the cutting surface of the concrete portion to melt the concrete. Further, the steel material portion is melted by using the heat of combustion (oxidation) of iron in the steel material that is burned in the atmosphere containing oxygen, which is formed by the assist gas that is coaxially injected with the laser light, and the high-pressure assist gas is used. Blow away and remove concrete and steel melts. Furthermore, by continuously generating a decarbonation explosion at 600°C or higher due to crushed stone aggregate or carbonate in concrete and a steam explosion at 200°C or higher contained water, a composite that is more efficiently melted than blown by gas The member can be blown off at a high speed and removed.

Specifically, as shown in FIGS. 1 and 2, when the laser light L is condensed in the laser head 20 constituting the long focus optical system and is irradiated from the nozzle 23 to the composite member 1, the vicinity of the focus position is obtained. In order to obtain an optical power surface density of about 1 MW/cm or more, the rough focus is aimed at the surface of the concrete 2 of the composite member 1, and then the concrete 2 and the steel plate are spread over a predetermined width in the cutting depth direction. 3 and 2 are melted smoothly at low speed and quasi-steadily, and the iron component in the steel plate 3 is 2Fe+(3/2)O ₂ =Fe ₂ O ₃ +824kJ with a gas containing oxygen at a high pressure and a high flow rate.
Start cutting as if it were blown away while burning with the combustion heat of. For cutting, the speed is increased from the almost stopped state to the optimum speed for cutting, then the speed is adjusted according to the steady state or the cutting condition, and the light energy controlled with high precision is locally concentrated on the cutting member. To heat and melt the material.

Regarding steel materials that burn in an atmosphere containing oxygen, as shown in each drawing of FIG. 3, steel plates (FIG. 3A) arranged on the front and back surfaces of the composite member, structural design such as reinforced concrete, Alternatively, a reinforcing steel material (Fig. 3(b) rebar 4, Fig. 3(c) wire mesh 5, coating lining 6) arranged at a predetermined position of concrete for the purpose of application like the coating lining also assists the combustion and oxidation action. Can play a role. Further, in accordance with the cutting work, a combustion and oxidation promoting material (Fig. 3(d) iron wire 7) such as iron powder, iron wire, strip steel plate, etc. may be continuously or intermittently additionally supplied to the laser irradiation portion. preferable.

On the other hand, a point where carbon dioxide such as calcium contained in aggregate or mortar paste in concrete is decarbonated at about 600°C or higher, and steam explosion at 200°C or higher due to crystal water and contained water is continuously cut. And in the vicinity thereof, the molten material such as the glassy molten material generated in the concrete is blown off at a high speed while maintaining a high temperature and a low viscosity, more efficiently than just blowing it off by the assist gas G. Can be removed.

Quantitatively, using a laser beam with an output of about 10 kW or less to a larger value, a composite member composed of a steel plate with a Lcm thickness of 0.5 to 1 cm and a width of 1 to 2 cm or more, and a concrete member with a thickness of about 10 cm is 10 cm. In the case of cutting at 1/min, the minimum amount of heat required is about 10 kW of laser heat and about 1.35 g of iron contained in the steel material×L/sec, the heat of combustion is about 10 kw×L. The heat of oxidation can be used.

FIG. 4 shows an example of the disassembled state (cut state) of the steel chimney (composite member 1) having the lining concrete 2 using the cutting device 10 of the present invention. In the figure, in order to show the configuration of the cutting device 10, only part of the chimney is drawn. The laser head 20 of the cutting device 10 of the present invention is arranged along the two axes (θ, r) of a positioning drive mechanism 30 installed on a mount (not shown) and has an arcuate traverse rail 32 that is concentric with the inner circumference of the chimney. It is supported via a slider (not shown) that is independently movable on a straight access rail 31 in the radial direction from the chimney center. As shown in the drawing, the laser head 20 is installed so as to face outward in the radial direction from the center of the chimney, and the nozzle tip 23a always keeps a predetermined standoff distance from the surface of the lining concrete 2 on the inner circumferential surface of the chimney to access rails. You can move over 31. Further, the laser head 20 can move in the circumferential direction along the traverse rail 32 as the cutting work progresses. These movement operations of the laser head 20 are automatic operation set by the control unit 36 based on a position signal obtained by a position detection sensor (not shown) that detects a standoff distance, a cut point, and the like. Alternatively, it can be manually operated by the operator based on the obtained position signals.

The cutting operation is started by the laser beam L and the assist gas G supplied from the laser oscillator 11 and the assist gas supply device 40 to the laser head 20, as in the case of the configuration described in FIG. The traverse speed is set to an appropriate speed as an initial value depending on the concrete thickness of the chimney that is the composite member 1, the steel plate thickness, the presence of other reinforcing members, etc., but the speed should be adjusted appropriately according to the actual cutting situation. Is preferred. In addition, in FIG. 4, the cutting work is performed such that the chimney as the composite member 1 is sliced into substantially horizontal slices, but among the rails 31 and 32 that support the laser head 20, the arc-shaped traverse rail 32 is used. Instead, by installing a linear rail (not shown) in the vertical direction and supporting the laser head 20 on this linear rail via a slider, the laser head 20 can run in the vertical direction. As a result, for example, the cutting member that has been cut into pieces can be further subdivided into a plurality of parts in the vertical direction.

The laser light L penetrates the chimney as shown in the drawing, but a laser beam dump 8 is arranged outside the chimney at the position where the laser light L penetrates the chimney. Since light energy is consumed by colliding with the dump truck 8, no external influence occurs. The laser beam dump 8 can be moved at a set speed while keeping a predetermined distance from the outer peripheral surface of the chimney in synchronization with a cutting operation by the laser light L, that is, an operation operation of the laser head 20 by a driving mechanism (not shown). Needless to say, various robots such as a known 6-axis robot arm mechanism can be used as the positioning drive mechanism of the laser head 20.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. That is, an embodiment obtained by combining technical means appropriately modified within the scope of the claims is also included in the technical scope of the present invention.

1 Steel-concrete composite member (composite member)
2 Concrete 3 Steel plate (steel material)
8 Laser Beam Dump 10 Cutting Device 11 Laser Oscillator 14 Optical Fiber 20 Laser Head 23 Nozzle 30 Positioning Drive Mechanism 40 Gas Supply Device G Assist Gas L Laser Light S Standoff Distance φ Nozzle Diameter

Claims (8)

While irradiating a laser beam having a long focal length so as to focus near the surface of the composite member of steel material and concrete, coaxial with the laser light, a gas containing oxygen by the laser light of the composite member It is characterized in that the composite member is sprayed at a cutting location, the composite member is cut by the heat energy of the laser light and the heat of combustion of iron contained in the steel material by the gas, and the melt generated by cutting is removed by the gas. Method for cutting steel-concrete composite member. The method for cutting a steel-concrete composite member according to claim 1, wherein a focal length of the laser beam on the light-collecting side is 500 mm or more. The concrete is a low-viscosity melt that is generated in the vicinity of and around the cutting point where a decarbonation explosion caused by the contained carbonate and a steam explosion caused by the crystal water and the contained water are continuously generated and removed by the gas. 1. The method for cutting a steel-concrete composite member according to 1. The steel concrete according to claim 1, wherein the surface of the composite member is irradiated with the laser light such that the distance between the tip of the nozzle and the surface of the composite member is substantially equal to the inner diameter of the nozzle of the laser head. Method for cutting composite member. A laser oscillator, a laser head to which laser light is guided from the laser oscillator through an optical fiber, and which emits laser light having a long focal length so as to focus near the surface of a composite member of steel and concrete, and the laser head A gas supply device for supplying a gas containing oxygen to the nozzle of the head; and a positioning drive mechanism for movably supporting the laser head while positioning and adjusting the nozzle tip of the laser head near the surface of the composite member. A device for cutting a steel-concrete composite member, which is provided with: The cutting device for a steel-concrete composite member according to claim 5, wherein a focal length of the laser beam on the light-collecting side is 500 mm or more. The steel-concrete composite member according to claim 5, wherein the positioning drive mechanism includes an access rail facing the composite member, and a traverse rail capable of moving the laser head along the extension direction of the surface of the composite member. apparatus. The apparatus for cutting a steel-concrete composite member according to claim 5, wherein the positioning drive mechanism is operated such that the inner diameter of the nozzle of the laser head and the distance between the tip of the nozzle and the surface of the composite member are substantially equal.

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