JPH11270153A - Demolition method of concrete surface layer part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce generation of fume and fine powder so as to prevent an operator and circumference from being polluted by irradiating laser rays onto the surface of concrete to form a plurality of slits, and giving shearing force to them to break from the roots and breaking away them. SOLUTION: An optical fiber 2 is connected to a laser generator 1, and the other end part is arranged oppositely to the surface of a concrete 1. The other end part of the optical fiber 2 is fitted to a light converging device 4. The other end part of the optical fiber 2 is scanned longitudinally and laterally along the concrete face 3a, and the concrete surface layer part 3b is melted and evaporated to form a plurality of slits 5. A tool is pessed to the surface layer part 3b from the side to give shearing force, and the concrete is broken from the roots of the slits 5 and broken away. The diameter of the laser ray is set to be under 3 mm, the energy density is over 50000 wat/cm<2> , and it is iodine laser of wave length of 10.6 μm Nd:YAG, 1.315 μm. The depth of the slit 5 is set over 1.2 times the longest side of the outer circumferential side of the concrete part surrounded with the slits.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dismantling a surface layer of concrete, and more particularly to a method for removing a contaminated layer of cement concrete or cement mortar, which is a surface layer which has been penetrated and contaminated with radioactive substances or chemical substances. The present invention relates to a method for disassembling a concrete surface layer portion suitable for carrying out the method.

[0002]

2. Description of the Related Art In nuclear facilities and chemical facilities, radioactive substances and toxic chemical substances may penetrate into walls and the like of the facilities to a depth of up to ten and several millimeters from the surface thereof and become contaminated. Conventionally, removal of the contaminated surface layer of cement concrete or cement mortar (hereinafter simply referred to as concrete) constituting the infiltrated contaminated wall or the like is performed by using a tool such as a breaker, a scabber, a planar, or the like. A typical method is to dismantle the surface layer by mechanically polishing and grinding.

[0003]

However, in these mechanical disassembly methods, when the concrete surface is polished and ground by the high-speed rotation of the cutting edge, the contaminated concrete is scattered as a large amount of fine powder, so There are problems such as contamination of the surroundings and secondary contamination of the surroundings. In addition, regardless of the presence or absence of contamination of the surface layer, the above-mentioned method causes a large amount of fine powder to be scattered, and the subsequent processing is also troublesome.

In addition, these mechanical methods not only involve a large amount of noise and vibration, but also generate a large reaction force during grinding or the like, so that remote operation by a robot or the like becomes difficult or the device itself becomes large. There is a problem that it must be changed.

[0005] The present invention provides a disassembly method capable of solving the above problems. In other words, an object of the present invention is to provide a method for dismantling a concrete surface layer portion that can be constructed with little scattering of fine powder, can be constructed with low vibration, low noise and low reaction force, and can be remotely operated by a robot or the like.

[0006]

In order to solve the above-mentioned problems, the invention described in claim 1 of the present invention is to irradiate a focused laser beam onto a target concrete surface to scan the surface. Forming a plurality of slits crossing each other on the concrete surface layer, and then applying a shearing force to the concrete surface layer, thereby breaking and separating the concrete surface layer from the root of the slit. It is intended to provide a method for dismantling a concrete surface layer.

Here, the concrete includes cement concrete and cement mortar. According to the present invention, by irradiating a focused laser beam along the concrete surface and scanning it vertically and horizontally, the concrete portion irradiated with the laser beam melts and evaporates, and the concrete surface intersects with a predetermined depth. A plurality of slits are formed.

As described above, by forming the slit by laser processing, a slit having a small width with low vibration and low noise is formed. As a result, the generation of fumes and fine powder during slit formation is reduced. Therefore, the generated fine powder can be easily sucked by the suction device, and the worker or the surroundings can be prevented from being contaminated with the fine powder and the like.

Further, since the root of the slit is weakened by the high temperature during the slit processing, the concrete surface layer is broken at the root of the slit by applying a slight shearing force, and the concrete surface layer is easily cut from the root of the slit. Peeled off.

[0010] In addition, the noise and vibration during dismantling work are extremely small, and the reaction force when applying a shearing force is small, so that remote control by a robot or the like is easy.

Next, according to a second aspect of the present invention, the focused laser light is different from the first aspect of the invention.
The beam diameter on the concrete surface is set to 3 mm or less, and the energy density is set to 50,000 watts / cm ² or more.

The reason why the beam diameter on the concrete surface is set to 3 mm or less is that if the beam diameter of the laser beam on the concrete surface exceeds 3 mm, fumes and fine powders are often generated, and it is difficult to prevent scattering by suction. Because there is.
The beam diameter is more preferably 2 mm or less.

The smaller the beam diameter, the better, but the lower limit of the beam diameter is limited to 0.5 mm due to the optical system such as a condenser lens. Also, the energy density was set to 50,000 watts / cm ² or more, when processing a slit, since the energy density of the laser beam is not 50,000 watts / cm ² or more is sufficient melt vaporization does not occur, the slits in the concrete This is because processing becomes difficult. The energy density of the laser beam needs to be 50,000 watts / cm ² or more, preferably 100,000 watts / cm ² or more.

The energy density of the laser beam can be adjusted by adjusting the output of the laser beam and the beam diameter of the laser beam on the concrete surface. The energy density (watt / cm ² ) of the laser light described above is defined as follows.

The energy density of the laser beam (watt / c
m ² ) = 4P / πd ² where P is the power of the laser light (watts) and d is the beam diameter of the laser light on the concrete surface (cm).

Next, a third aspect of the present invention is directed to the first aspect.
Or 2 with respect to the configuration described in 2 above.
06 μm Nd: YAG laser, or wavelength 1.315
The slit processing is performed using a μm iodine laser and transmitting a laser beam from a laser oscillator to the vicinity of the concrete surface with an optical fiber.

According to the present invention, by transmitting the laser light from the laser oscillator through the optical fiber, the laser light can be easily scanned along the concrete surface.
Here, Nd: YA having a wavelength of 1.06 μm is applied to the laser light.
The reason for using a G laser or a 1.315 μm wavelength iodine laser is that these lasers enable transmission with an optical fiber even at high output.

Other laser beams (eg, CO ₂ laser, 10.6 μm) cannot be transmitted through an optical fiber.
Claim 3 of the present invention cannot be realized. Next, in the invention described in claim 4, in the configuration described in any one of claims 1 to 3, the depth of the slit is the longest of the outer periphery of the concrete portion surrounded by the slit. 1.2 of the side
It is characterized by being twice or more.

By setting the depth of the slit at least 1.2 times the longest side of the outer periphery of the concrete portion surrounded by the slit, the slit can be reliably broken at the root of the slit.

It is desirable that the value be twice or more.
Here, since the slit depth is usually determined by the thickness of the surface layer to be peeled (contaminated), the slit interval is adjusted to be set to the above value. For this reason, the upper limit of the ratio between the side and the slit depth is usually limited from the minimum value of the slit interval.

[0021]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view for explaining a slit and the like, and FIG. 2 is a sectional view taken along line AA.

As shown in FIG. 2, one end of an optical fiber 2 is connected to the output portion of the laser oscillator 1, and the other end of the optical fiber 2 is arranged to face the surface of the concrete 3 to be processed. . The other end of the optical fiber 2 is provided with a condensing device 4
Is mounted, and is operated by a robot arm or the like (not shown). Of course, the work may be carried out by directly grasping by an operator.

Then, the other end of the optical fiber 2 is scanned vertically and horizontally at predetermined intervals along the concrete surface 3a while operating the laser oscillator 1. As a result, the laser light output from the laser oscillator 1 is
Is transmitted to the concrete surface 3a, and the concrete surface layer 3b melts and evaporates along the scanning direction to form a plurality of slits 5.

The plurality of slits 5 are formed in a lattice, for example, as shown in FIG. Depth z of slit 5
Is adjusted by the scanning speed of the laser beam according to the depth of the osmotic contamination to be decontaminated, and the depth z is adjusted to the outer circumference of the concrete portion (for example, the hatched portion in FIG. 1) surrounded by the slit 5. Of the sides x and y, the interval between the slits 5 is set to be 1.2 times or more, preferably twice or more, the length of the longest side (for example, x).

That is, z ≧ 1.2 · x. In addition,
In the above example, since the outer peripheral shape of the concrete portion surrounded by the slit 5 has a rhombic shape, two sides x and y are provided.
However, if the lengths of the four sides are different, the longest side of the four sides may be focused on. Further, from the relationship between the slit interval and the slit depth, the slit depth z
May be determined.

When processing the slit 5, the energy of the laser light
Lug density is 50,000 watts / cm ^TwoAbove, preferably
100,000 watts / cm^TwoSet above. This laser
Adjustment of the energy density of light depends on the output of laser light and
Laser beam focused on concrete 3 surface
This is done by adjusting the diameter.

The fumes and fine powder generated when processing the slit 5 are sucked by a suction device (not shown) as necessary to prevent scattering. At this time, the slit width δ is set narrow by setting the diameter of the laser beam on the surface of the concrete 3 to 3 mm or less, preferably 2 mm or less.

As a result, the generation of fumes and fine powder at the time of slitting is reduced, and scattering by suction can be reliably prevented. In addition, the generation of fine powder can be suppressed to a small level and low noise and low vibration can be achieved also in the point that melting and evaporation are performed by laser light instead of grinding.

The type of laser used for slit processing is not particularly limited. Laser energy density is 5
If it is 0000 watts / cm ² or more, for example, the wavelength 1
0.6 μm carbon dioxide laser (CO ₂ laser), wavelength 5
Various lasers can be used, including a μm CO laser, a 1.06 μm Nd: YAG laser, and a 1.315 μm iodine laser.

Here, N can be transmitted by an optical fiber.
d: Since only a YAG laser and an iodine laser are used, when another laser is used, it is necessary to transmit the light using a mirror or the like. When the processing of the slit 5 is completed, as shown in FIG. 3, a rotating or vibrating tool 6 is pressed from the side of the concrete surface portion 3b to give a shearing force to the concrete surface portion 3b, and the tool 6 is removed. By scanning along the concrete surface 3a, the concrete surface layer 3b is broken and peeled in order from the root of the slit 5.

The portion denoted by reference numeral 6a is a portion that applies a shearing force by rotation or vibration. Although the shear force is applied from the side surface of the surface layer portion 3b, the shear force to be applied may be small as described later, and the shear force may be applied by contacting the concrete surface 3a. .

At this time, since the concrete portion at the base of the slit 5 is weakened due to the high temperature during the slit processing, the concrete surface layer 3b is broken and peeled from the base of the slit 5 with a slight force of the tool 6. And because concrete 3 is almost broken into small blocks and peels off,
The exfoliated concrete pieces can be easily collected.

For this reason, the generation of dust is small at the time of peeling, but if necessary, the dust may be sucked and collected at the same time as the peeling. As described above, since the peeling can be performed with a small force, the noise and the vibration are extremely small even in the peeling operation using the tool 6. Further, since the reaction force when the shear force is applied by the tool 6 is small, remote peeling by a robot or the like is also possible.

Here, the scanning direction of the tool 6 is set to, for example, a direction in which the slit interval is small, so that the reaction force can be further reduced. The present invention is applicable to various types of cement concrete and cement mortar, such as ordinary concrete, high-strength concrete, ultra-high-strength concrete, heavy concrete, lightweight concrete, ordinary mortar, lightweight mortar, resin mortar, polymer cement mortar, joint mortar, pasting mortar, and the like. Applicable to

In this embodiment, the concrete surface layer 3b contaminated by radioactivity and the like is dismantled. However, the present invention is not limited to this. As long as the work is to dismantle the surface layer of concrete, other works such as seismic reinforcement can be applied.

In the above embodiment, the laser light is transmitted by the optical fiber 2, but the laser light may be scanned by using a mirror or the like. However, using the optical fiber 2 is a simpler facility.

Further, in the above embodiment, the case where a plurality of slits 5 are formed in a rectangular lattice shape is described as an example. For example, the outer peripheral shape of the concrete portion surrounded by the slits 5 is triangular or pentagonal. The slits 5 may cross each other so that Further, the intervals between the slits 5 do not need to be equal, and the extending directions of the slits 5 do not necessarily have to be parallel. Furthermore, the extending direction of the slit 5 does not necessarily need to be a straight line.

[0038]

EXAMPLE Nd: YA transmitted by an optical fiber 2 against a wall of ordinary concrete 3 having a compressive strength of 300 kg / cm ^2.
A plurality of intersecting slits 5 were processed by condensing and irradiating a G laser with an optical system (such as a lens) and scanning the laser in the vertical and horizontal directions. The irradiation conditions of the laser beam were as follows.

Laser power: 1000 watts Energy density of laser on concrete surface: 130
Scanning speed of 000 watt / cm ² laser: 300 mm / mim The width of the slit 5 thus obtained is about 1 mm,
The interval between slits 5 is 5 mm both vertically and horizontally.
The depth of the slit 5 was 10 mm.

After the slitting, the rotating steel tool 6 is pressed against the side surface of the concrete surface portion 3b to scan while sucking, so that the surface of the concrete 3 is broken from the root of the slit 5 and peeled off. Was completed. There was almost no dust at the time of peeling, and the 3 small pieces of concrete that had fallen off and peeled could be easily collected. Also, noise and vibration were small.

The reaction force generated on the tool 6 at the time of peeling is:
It was in the range of 2.5-5 kg.

[0042]

As described above, in the concrete surface layer dismantling method according to the present invention, when the surface layer is dismantled, the scattering of fine powder is suppressed, and the construction at the time of dismantling is performed with low vibration. This has the effect of being implemented with low noise.

Moreover, since the reaction force at the time of disassembly is small, there is an effect that an apparatus which can be easily remotely operated by a robot or the like can be provided. This is particularly effective when the contaminated concrete surface is dismantled for decontamination.

In particular, when the invention described in claim 2 is adopted, the scattering of fine powder generated at the time of forming the slit can be reliably suppressed, and the slit having a desired depth can be surely formed. There is.

In addition, when the invention described in claim 3 is adopted, the use of an optical fiber makes it possible to easily scan a laser beam along a concrete surface, thereby simplifying the slit forming operation. effective.

Further, by adopting the invention described in claim 4, there is an effect that the concrete surface layer can be reliably peeled off at the root position of the slit.

[Brief description of the drawings]

FIG. 1 is a view showing a concrete surface and a formation state of a slit according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a diagram showing a state in which a shear force is applied.

[Explanation of symbols]

 Reference Signs List 1 laser oscillator 2 optical fiber 3 concrete 3a concrete surface 3b concrete surface layer 5 slit z slit depth δ slit width

Claims (4)

[Claims] A concrete surface is irradiated with a focused laser beam and scanned to form a plurality of slits crossing each other in a concrete surface layer, and thereafter, a shear is formed in the concrete surface layer. A method for dismantling a concrete surface layer portion, wherein a force is applied to break the surface layer portion of the concrete from the base of the slit and peel off. 2. A method according to claim 1, wherein the focused laser beam has a beam diameter on a concrete surface of 3 mm or less and an energy density of 50,000 watts / cm ² or more. The method for dismantling a concrete surface layer according to claim 1. 3. The laser light having a wavelength of 1.06 μm N
d. The slit processing is performed by using a YAG laser or an iodine laser having a wavelength of 1.315 μm, and transmitting a laser beam from a laser oscillator to an area near the concrete surface by an optical fiber. 2
The method for dismantling a concrete surface layer described in 1. 4. The method according to claim 1, wherein the depth of the slit is at least 1.2 times the longest side of the outer periphery of the concrete portion surrounded by the slit. The method for dismantling a concrete surface layer described in 1.