JP2003239693A - Tunnel fire-resistive covering structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tunnel fire-resistive covering structure in which the effect of high fire resistance or the like can be expected by inhibiting the generation of a crack in which a maximum crack width due to the drying shrinkage or the like of a covering layer after a construction reaches 1 mm or more. <P>SOLUTION: The tunnel fire-resistive covering structure is composed of a reinforcing material 1, in which abutting sections 3 bent and machined for a fixing on the wall surface of a tunnel by fixtures and plate-shaped meshy main body sections 2 arranged at an interval from the wall surface of the tunnel are formed in an irregular shape, and a cement wet-type fire-resistive spraying material being covered on the wall surface of the tunnel in a fixed thickness under the state, in which the reinforcing material 1 is buried, and having the ratio of drying shrinkage of 0.3% or less. The main body sections 2 of the reinforcing material 1 are buried at places separate from the wall surface of the tunnel at a distance of one fourth to three fourth of the thickness of the covering layer consisting of the cement wet-type fire-resistive spraying material. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tunnel fireproof coating structure which is formed on a wall surface of a tunnel as a surface layer portion and which comprises an uneven reinforcing material and a specific cement-based wet fireproof spraying material.

[0002]

2. Description of the Related Art When a fire occurs inside a tunnel, the temperature inside the tunnel becomes extremely high and the concrete forming the wall surface of the tunnel peels off and falls. Therefore, a wet refractory material such as a cement-based material is sprayed on the surface of the concrete forming the wall surface of the tunnel to form a refractory coating layer. Such a spraying method is excellent in that the construction work is efficient and a seamless finish can be obtained. However, the wet refractory material to be sprayed has a large amount of kneading water to enhance the fluidity in order to facilitate the construction work. Therefore, the fire-resistant coating material made of a wet-type fire-resistant material has a large dry shrinkage ratio, and cracks often occur after construction.

In particular, when the wall surface of a tunnel is fireproof coated, in addition to severe environmental conditions such as a large wind pressure caused by a vehicle passing through the tunnel, a large arc-shaped cross section is constructed as an integral structure, Cracks tended to concentrate in one place, and the crack width tended to increase. In addition, since the temperature inside the tunnel expected at the time of a fire is extremely high (for example, about 1200 ° C.), even a crack with a maximum crack width of about 1 mm may be a weak point in fire resistance. .

On the other hand, when a cement-based material is sprayed to form a coating layer, a reinforcing material such as a wire mesh is embedded in the coating layer made of the cement-based material to improve the strength of the coating layer and cause cracks. Techniques for suppressing peeling of the coating layer and the coating layer are known. For example, Jikken 4-42395
In the gazette, in a underground cavity such as a tunnel or an underground power plant, a reinforcing material composed of a welded wire net and expanded mesh-shaped expanded metal to be welded on both sides of the welded wire net is arranged in spray concrete. , A technique for increasing the resistance when a bending moment is applied to shotcrete and preventing the occurrence of cracks.

[0005]

In order to secure high fire resistance on the wall surface of the tunnel, it is necessary to suppress the occurrence of cracks having a maximum crack width of about 1 mm as described above. However, when using a conventional flat wire mesh for reinforcement, which is often embedded in a tunnel fireproof coating layer,
Although it is possible to suppress the occurrence of cracks to some extent, as compared with the case where a reinforcing wire mesh is not provided, particularly in a fireproof coating layer on a curved wall surface such as a tunnel inner wall surface, it is difficult to make the reinforcing effect uniform, Depending on the location, the maximum crack width could not be made sufficiently small. Also,
As described above, there is room for improvement with respect to the problem of the wet refractory material itself (that is, easy cracking after construction) due to the large amount of kneading water. Therefore, it is an object of the present invention to obtain a tunnel refractory coating structure in which the fire resistance is improved by reducing the maximum crack width.

[0006]

DISCLOSURE OF THE INVENTION As a result of earnest studies for solving the above problems, the present inventor has conducted a tunnel coating formed of a specific cement-based wet fire-resistant spraying material with a specific reinforcing material having an uneven shape. The present invention has been completed based on the finding that the embedding in a depth within a specific range of a layer suppresses the generation of large cracks having a maximum crack width of 1 mm or more. That is, in the tunnel fireproof coating structure of the present invention (claim 1), an abutting portion fixed on the wall surface of the tunnel by a fixture (for example, a part of a flat plate-shaped member has a substantially U-shaped cross section). And a mesh-shaped main body portion (for example, a flat plate-shaped portion other than the bent contact portion) arranged apart from the wall surface of the tunnel.
And a cement having a dry shrinkage of 0.3% or less, which is coated on the wall surface of the tunnel with a predetermined thickness so that the reinforcing material is embedded. 1. A tunnel fire resistant coating structure made of a wet wet fire resistant spraying material, wherein the main body of the reinforcing member is 1/4 to 3 times the thickness of a coating layer made of the wet wet fire resistant cement material from the wall surface of the tunnel. It is characterized in that it is embedded at a position separated by a distance of / 4. Thus, for the reinforcing material, the body portion of the specific reinforcing material having an uneven shape,
By arranging it in a specific region of a coating layer made of a specific cement-based wet fire-resistant spray material, large cracks can be suppressed, and as a result, the fire resistance of the coating layer can be improved. Further, the cement-based wet fire-resistant spraying material used in the present invention has fire resistance performance,
In addition, the drying shrinkage rate may be 0.3% or less, and other performances may be the same as or higher than those of the cement-based wet fire-resistant spraying material conventionally used for tunnel spraying construction.

The diameter of the wire material forming the mesh-shaped main body of the reinforcing material is preferably 0.8 to 3.0 mm (claim 2). If the diameter of the wire is within this range, it is possible to more effectively suppress the occurrence of large cracks with a maximum crack width of 1 mm or more, and at the time of attaching a reinforcing material or coating a cement-based wet fireproof material. In addition, since the main body of the reinforcing material is easily bent, it is easy to arrange the main body of the reinforcing material so that the distance from the wall surface is substantially constant after construction even on a curved wall surface such as a tunnel. As the wire rod, a metal wire rod such as a stainless steel wire, an iron wire, or a resin-coated iron wire is preferably used. A preferable example of the mesh-shaped main body of the reinforcing material is made of stainless steel, and is 20 to 120.
Those having an opening size of mm can be mentioned (Claim 3). If the mesh-shaped main body is configured to have such a material and a mesh size, it is possible to more effectively suppress the occurrence of large cracks having a maximum crack width of 1 mm or more over a long period of time. At the same time, the spraying operation of filling the cement-based wet fire-resistant spraying material on the back side (wall surface side) of the mesh-shaped main body becomes easy. The thickness of the coating layer made of the cement-based wet fireproof material is generally 20 to 80 mm (claim 4). A preferable example of the above specific cement-based wet fire-resistant spraying material is one containing vermiculite and / or perlite and having a compressive strength of 1.5 MPa or more at 28 days of age (claim 5). ). By including vermiculite and / or perlite as a constituent component in this manner, fire resistance can be improved, and since the compressive strength is not less than a predetermined value, the occurrence of cracks can be further suppressed and the solidity can be improved. An excellent tunnel fireproof coating structure can be obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the tunnel fireproof coating structure of the present invention will be described below with reference to the drawings. 1 is a perspective view partially showing an example of a reinforcing material used in a tunnel fireproof coating structure of the present invention, FIG. 2 is a plan view showing the overall shape of the reinforcing material shown in FIG. 1, and FIG. 1 is a plan view showing a state in which the reinforcing material shown in FIG. 1 is fixed on a wall surface of a tunnel by a fixture, FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3, and FIG. 6 is a cross-sectional view taken along the line BB in FIG. 3, and FIG. 6 shows a tunnel fireproof of the present invention in which the reinforcing material shown in FIG. 5 is embedded in a coating layer made of a cement-based wet fireproof spraying material. A diagram showing a state in which a coating structure is formed,
FIG. 7 is a diagram showing an example of an abutting part other than the abutting part shown in FIG. 4, and FIG. 8 is a cross-sectional view showing an example of the tunnel fireproof coating structure of the present invention formed on the wall surface of the tunnel. FIG. 9 is a cross-sectional view showing the tunnel fireproof coating structure shown in FIG. 8 in a partially enlarged manner.

The reinforcing material 1 used in the tunnel fireproof coating structure of the present invention, as shown in FIGS. 1 to 5, is formed by bending a mesh-like plate-like member to form a main body 2 which is a flat plate-like portion. And an abutting part 3 having a substantially U-shaped cross section and extending in a groove shape between the main body parts 2 are alternately formed. As shown in FIG. 1, the main body 2 is composed of a vertical wire 6 and a horizontal wire 7, and is formed in a mesh shape having a substantially square mesh. The mesh size of the mesh of the main body 2 is preferably 20 to 120 mm. If the dimension is within this numerical range, as described above, the cement-based wet fire-resistant spraying material after disposing the reinforcing material 1 can be easily applied, and the occurrence of cracks can be effectively suppressed. .

As shown in FIG. 4, the abutting portion 3 is a main body portion 2.
Slope part 3a extending obliquely downward from the edge of the horizontal part, a horizontal part 3b extending horizontally from the lower end of the slope part 3a, and a slope extending obliquely upward from the end of the horizontal part 3b and intersecting the edge of the adjacent main body part 2. And part 3a. Here, the inclination angle of the slope portion 3a is, for example, the horizontal portion 3a.
40 to 8 with respect to the extended surface of b (or the wall surface of the tunnel)
It is set to be 0 degrees. When the inclination angle is close to 90 degrees, it becomes difficult to insert the fixture 4 (in particular, the anchor 4a) into the abutting portion 3 when the fixture 4 (see FIG. 5) is attached, and workability may be slightly deteriorated. There is.

As shown in FIGS. 1 and 3 to 5, the abutting portion 3 includes two vertical wire rods 6 extending in the depth direction of the wall surface of the tunnel at the bottom of the recess between the main body portions 2, and the vertical wire rods. 6 and a horizontal wire 7 that intersects vertically. The vertical wire 6 is
As shown in FIG. 4 and FIG. 7, the side where the wall surface 8 of the tunnel is located with respect to the horizontal wire 7 (that is, the wall surface 8 of the tunnel exists when the space is divided into two with the horizontal wire 7 as a boundary. It is preferable that it is fixed to the horizontal wire 7 by welding or the like at a position which is the side) and can abut against the wall surface 8 of the tunnel.

As shown in FIG. 5, the two vertical wires 6 and 6 forming the contact portion 3 together with the bent horizontal wire 7 are fixed to the wall surface 8 of the tunnel by the fixture 4 including the anchor 4a and the washer 4b. Anchor 4a so that it can be fixed
Are large enough to be placed inside and extend in parallel at a predetermined interval such that the size is smaller than the diameter of the washer 4b. These two vertical wires 6,
6 is, for example, as shown in FIG.
7 may be arranged at a predetermined interval below the horizontal portion of the horizontal portion of the horizontal portion of the horizontal portion of the horizontal portion of the fold portion 3 (that is, the horizontal portion of the horizontal portion of the fold portion 3) It may be arranged on an extension of the horizontal portion of the wire 7 and at a position where it can be brought into contact with the wall surface 8 of the tunnel). In any case, after the washer 4b is placed on these two vertical wire members 6 and 6, the anchor 4a is driven into the wall surface 8 of the tunnel through the washer 4b, so that the reinforcing member 1 is made into the washer 4b.
And is fixed on the wall surface 8 of the tunnel.

As shown in FIGS. 4 and 7, the two vertical wires 6 and 6 forming the abutting portion 3 together with the horizontal wire 7 are arranged so as to come into contact with the wall surface of the tunnel. Even if the washer 4b is pressed by driving the anchor 4a, the reinforcing material 1 is not deformed. The two vertical wires 6 and 6 that form the contact portion 3 are arranged at predetermined positions of the contact portion 3 unlike the vertical wire material 6 of the main body portion 2 that has a gap of a predetermined opening size. Therefore, it is necessary to design in advance. The distance between the contact portions 3, 3 (see FIG. 2) is usually
It is about 100 to 700 mm. If the distance is within this numerical range, the state of attachment to the wall surface 8 of the tunnel can be made strong.

In the tunnel fireproof coating structure of the present invention, the distance between the wall surface 8 of the tunnel and the main body portion 2 of the reinforcing member 1 (see FIGS. 5 and 6) is determined by the thickness of the coating layer 5 (that is, the wall surface of the tunnel). 8 to the surface of the coating layer 5) 1 /
It is set to 4 to 3/4. If the distance is within this range, the reinforcing effect of the reinforcing material 1 becomes large, and it becomes easy to suppress the occurrence of large cracks. If the distance is less than 1/4, the effect of suppressing cracks on the surface of the coating layer 5 becomes insufficient, which is not preferable. If the distance exceeds 3/4, the heat transferred to the reinforcing material 1 at the time of fire increases, which is not preferable. Further, the thickness of the coating layer 5 made of the cement-based wet fire-resistant spraying material is preferably about 20 to 80 mm. When the thickness is less than 20 mm, it becomes difficult to obtain sufficient fire resistance, and when the thickness exceeds 80 mm, the reinforcing effect is insufficient by using only one reinforcing material 1 and the reinforcing material 1
It is necessary to take measures such as using a plurality of.

The diameter of the wire (vertical wire 6 and horizontal wire 7) constituting the reinforcing member 1 is preferably 0.8 to 3.0 mm. If the diameter is less than 0.8 mm, the rigidity of the reinforcing material 1 is low, so that the reinforcing material 1 may be deformed during transportation before being mounted on the wall surface of the tunnel, and in order to obtain a sufficient reinforcing effect. Since the opening needs to be less than 20 mm, it is difficult to fill the cement-based wet fire-resistant spray material on the back side of the reinforcing material 1. If the diameter exceeds 3.0 mm, the rigidity of the reinforcing material 1 becomes large, so it takes time and effort to attach it to the curved surface portion of the wall surface of the tunnel, and the main body portion 2 is made to match the shape of such curved surface portion. Hard to bend. Examples of the wire material that constitutes the reinforcing member 1 include a wire material made of stainless steel, an iron wire, and a metal wire material such as a resin-coated iron wire. Among them, a wire made of stainless steel has high strength and is excellent in corrosion resistance and fire resistance, and thus is preferably used as a material in a fireproof coating structure. The material and diameter of the vertical wire 6 and the horizontal wire 7 are usually the same, but they may be different.

The overall shape of the reinforcing material 1 is not particularly limited, but preferably, as shown in FIG. 2, it is formed in a rectangular shape such that the direction in which the abutting portion 3 extends in the strip shape is the longitudinal direction. . With such a shape, even when the construction surface to which the reinforcing member 1 is attached is the curved surface portion of the wall surface of the tunnel, the direction in which the contact portion 3 extends in the strip shape is such that the cross section of the curved surface portion of the wall surface is arcuate. By orienting the reinforcing material 1 so as to be perpendicular to a certain direction, it becomes easy to dispose the main body portion 2 of the reinforcing material 1 so that the distance from the construction surface is substantially uniform. The dimension of the reinforcing material 1 is not particularly limited, but when it has a rectangular shape, for example, the longitudinal dimension is about 1 to 6 m and the lateral dimension is about 0.5 to 2.5 m.

As a cement-based wet refractory material for embedding the reinforcing material 1 to form a coating layer, a material having a dry shrinkage ratio of 0.3% or less, preferably 0.1 to 0.3% is used. Used. If the dry shrinkage exceeds 0.3%,
It becomes impossible to sufficiently suppress large cracks (cracks having a maximum crack width of 1 mm or more) after construction. If the drying shrinkage ratio is set to be less than 0.1%, the amount of water in the cement-based wet fire-resistant spraying material must be significantly reduced, so that the fluidity may be reduced and the workability of the spraying work may be reduced. is there. Further, if a coating material is used instead of a spraying material, the work of forming the coating layer 5 takes a lot of time due to the presence of the reinforcing material 1, and the work efficiency is reduced. Among the cement-based wet fire-resistant spraying materials, vermiculite and / or perlite (particularly, hard perlite) is contained, and the material age is 28.
A material having a compression strength of 1.5 MPa or more in a day is particularly preferably used. Thus vermiculite and /
Alternatively, by containing perlite, fire resistance can be improved. Further, by setting the compressive strength within this range, it is possible to further suppress the occurrence of cracks and obtain a solid tunnel fireproof coating structure.

In the present specification, the term "compressive strength of 28 days old" means that after the cement-based wet fire-resistant spraying material is sprayed into a mold (φ150 × 40 mm), 20
Compressive strength after curing for 28 days in an atmosphere of ℃ and relative humidity of 90% or more. In addition, in the present specification, the “dry shrinkage rate” refers to a value measured as follows. That is, first, a cement-based wet fire-resistant spraying material is sprayed into a mold (length 50 cm x width 50 cm x height 3 cm) to form a coating layer having a thickness of 3 cm, and then a temperature of 20 ° C and a relative humidity of 90. Curing up to 3 days of age in a% atmosphere. After curing, a gauge plug (base length 25 cm) is attached diagonally to the center of the surface of the coating layer, and the base length is measured using a Foitmer tester. After measurement, temperature 20
The sample is dried in an atmosphere at 60 ° C. and a relative humidity of 60% ± 5%, and the measurement is performed again at the age of 13 weeks of the dry material. The shrinkage rate obtained from the measured value of the base length at the time of 0 weeks of dry material and the measured value at the time of 13 weeks is the dry shrinkage rate. The content rate of vermiculite and / or perlite in the above cement-based wet fire-resistant spraying material (however, the content rate of the total amount when both are included) is preferably 5 to 30% by weight,
It is particularly preferably 10 to 25% by weight. The content rate is 5
If it is less than wt%, the improvement of fire resistance and the like due to the addition of vermiculite or perlite will be insufficient, and if the content exceeds 30 wt%, the strength may decrease.

The type of cement in the cement-based wet fire-resistant spray material is not particularly limited, but as a preferred example,
Examples include refractory cement and alumina cement. The content of cement in the cement-based wet fire-resistant spraying material (excluding water) is preferably 50% by weight or more. Examples of the composition of the cement-based wet fire-resistant spray material include 50 to 60 parts by weight of cement, 15 to 20 parts by weight of vermiculite and / or perlite, and 10 to 10 parts of mica.
15 parts by weight and 15 to 20 parts by weight of limestone. Besides this,
If necessary, a chemical admixture such as an organic shrinkage reducing agent or a water reducing agent can be added. Mix these ingredients,
After producing the premix material, kneading water is added and used as a spraying material. The amount of water in the cement-based wet fireproof material is 100 parts by weight of the premix material,
Usually, it is 75 to 110 parts by weight. Spraying after kneading the premix material and water may be performed by a conventional method.

Next, a method for forming the tunnel refractory coating structure of the present invention using the reinforcing material 1 shown in FIG. 1 will be described. In order to form a tunnel fireproof coating structure, first, a reinforcing material 1 (Fig. 1,
(See Fig. 2). At this time, the position where the fixing tool is attached is, for example, a position indicated by X in FIG. The operator is to contact the contact portions 3 at both ends in the lateral direction and the contact portion 3 at the center.
The reinforcing material 1 is fixed to the and by using a fixing tool 4 such as an anchor bolt. In order to connect the reinforcing members 1 to each other, the neighboring portions of the adjacent reinforcing members 1 may be overlapped with each other and the wire members of the two reinforcing members 1 may be fastened to each other using a fastening means such as a fastening wire. . The reinforcing material 1 is previously bent so that the distance between the main body 2 and the wall surface of the tunnel is within the range of 1/4 to 3/4 of the thickness of the coating layer from the tunnel wall surface. After the reinforcing material 1 is attached to the entire area of the wall surface of the tunnel to be constructed in this manner, the above-mentioned cement-based wet fire-resistant spraying material is sprayed to form the coating layer 5 having a predetermined thickness. At that time, the main body portion 2 of the reinforcing member 1 is slightly curved to have a shape along the wall surface. Then, by forming the main body 2 along the wall surface in this manner, a substantially uniform coating structure can be obtained.

[0021]

EXAMPLES [1. Preparation of Cement-Based Wet Fireproof Spraying Material] (1) Premix Material As premix materials, premix material A and premix material B having the following compositions were used. [Composition of premix material A] Ordinary Portland cement: 52.0% by weight Limestone: 17.5% by weight Mica: 12.0% by weight Vermiculite: 11.3% by weight (Brand name: Vermiculite Super Fine, manufactured by Mikata Shoko) ) Vermiculite: 6.8 wt% (Brand name: Vermiculite Fine, manufactured by Mikata Shoko Co., Ltd.) [Composition of premix material B] Ordinary Portland cement: 53.3 wt% Limestone: 18.0 wt% Mica: 12.2 wt% % Hard pearlite: 8.3% by weight (Product name: Hard pearlite No. 1, manufactured by Taiheiyo pearlite, particle size: 0.6 mm
Hard pearlite: 8.2% by weight (trade name: Hard pearlite No. 3, manufactured by Taiheiyo pearlite, particle size: 2.5 mm
Less than)

(2) Kneading method Examples 1 to 5 and Comparative Examples 1 and 2 100 parts by weight of the above-mentioned premix material A to 100 parts by weight and 85 parts by weight of water are put into a mixing tank all at once and kneaded. Then, a cement-based wet refractory material was prepared. Example 6 100 parts by weight of materials 1 to 3 of the premix material A and 110 parts by weight of water were put into a mixing tank all at once and kneaded to prepare a cement-based wet fire-resistant spraying material. Examples 7 and 8 100 parts by weight of the above premixed materials B to 85 parts by weight of water and 85 parts by weight of water were put into a mixing tank all at once and kneaded to prepare a cement-based wet fire-resistant spraying material. Example 9 100 parts by weight of the above-mentioned premix material B to 75 parts by weight of water and 75 parts by weight of water were put into a mixing tank all at once and kneaded to prepare a cement-based wet fire-resistant spraying material. Comparative Example 3 100 parts by weight of the above-mentioned premix materials B to 110 parts by weight of water and 110 parts by weight of water were put into a mixing tank all at once and kneaded to prepare a cement-based wet fire-resistant spraying material.

[2. Measurement of physical properties of cement-based wet fire-resistant spraying material] (1) Compressive strength Kneading cement-based wet fire-resistant spraying material into a form (φ1
(50 × 40 mm) and then cured for 28 days in an atmosphere of 20 ° C. and a relative humidity of 90% or more, and the compressive strength after curing was measured. The results are shown in Table 1 (experimental example using premix material A) and Table 2 (experimental example using premix material B). (2) Dry shrinkage ratio In a formwork (length 50 cm x width 50 cm x height 3 cm) in which a cement-based wet fire-resistant spraying material is kneaded with anti-friction sheets (made of polytetrafluoroethylene) on the bottom and side surfaces. After casting by spraying on, temperature 20
It was aged up to 3 days in an environment of ° C and relative humidity of 90%.
After curing, a gauge plug (base length 25 cm) was attached diagonally to the center of the surface of the cement-based wet fire-resistant spraying material in the mold, and the base length was measured using a Foitmer tester. Further, the sample was dried in an atmosphere of a temperature of 20 ° C. and a relative humidity of 60% ± 5%, and the measurement was performed again at the time of 13 weeks of dry material. The shrinkage rate of the cement-based wet fire-resistant spraying material at this point was defined as the dry shrinkage rate. The results are shown in Tables 1 and 2.

[3. Crack Test] (1) Examples 1 to 9 Various stainless steel reinforcing materials shown in Table 1 (however, shown in FIG. 2 are targeted for construction of a substantially semicircular wall surface having a diameter of 5 m and made of tunnel lining concrete. With such a structure, the length dimension is 5 m and the width dimension is 1 m)
Was mounted on the construction surface from the side such that the longitudinal direction thereof coincided with the depth direction of the tunnel. Then, the above-mentioned cement-based wet fire-resistant spraying material was sprayed onto the construction surface so that the stainless steel reinforcing material was embedded and a coating layer having a predetermined thickness was formed. After that, temperature 20 ℃, relative humidity 60
%, And the maximum crack width after 91 days was measured. The maximum crack width was measured using a crack scale. (2) Comparative Examples 1 to 3 When no stainless steel reinforcing material is used (Comparative Example 1), when the height of the stainless steel reinforcing material is out of the range defined by the present invention (Comparative Example 2), cement-based wet refractory. An experiment was conducted in the same manner as in Examples 1 to 9 in each case where the drying shrinkage ratio of the sprayed material was outside the range specified in the present invention (Comparative Example 3). The results are shown in Tables 1 and 2.

[0025]

[Table 1]

[0026]

[Table 2]

As shown in Table 1, the height of the stainless steel reinforcing material from the steel plate is within the range of 1/4 to 3/4 of the thickness of the coating layer made of cement-based wet fire-resistant spraying material (25
To within 75%), and the drying shrinkage rate is 0.
When 3% or less of the cement-based wet fire-resistant spraying material is used, the maximum crack width is 0.5 mm or less, and excellent fire resistance can be expected. On the other hand, in Comparative Example 1, although the cement-based wet fire-resistant spraying material having a dry shrinkage ratio within the numerical range specified in the present invention was used, since the stainless steel reinforcing material was not used, the maximum crack width was 2.0 mm. And is getting bigger. In Comparative Example 2, the height of the reinforcing material from the steel plate is out of the range defined by the present invention, so that the maximum crack width is as large as 1.5 mm. In Comparative Example 3, the dry shrinkage ratio of the cement-based wet fire-resistant spraying material is out of the range specified by the present invention, so that the maximum crack width is as large as 2.8 mm.

[0028]

EFFECTS OF THE INVENTION The tunnel fireproof coating structure of the present invention is a reinforcement having unevenness in a specific height region of a coating layer made of a cement-based wet fireproof spraying material having a small drying shrinkage rate which is coated on the wall surface of the tunnel. Since the main body of the material is arranged and large cracks having a maximum crack width of 1 mm or more due to drying shrinkage of the coating layer after construction are suppressed, excellent fire resistance can be expected.

[Brief description of drawings]

FIG. 1 is a perspective view partially showing an example of a reinforcing material used in a tunnel fireproof coating structure of the present invention.

FIG. 2 is a plan view showing the overall shape of the reinforcing material shown in FIG.

FIG. 3 is a plan view showing a state in which the reinforcing material shown in FIG. 1 is fixed on a wall surface of a tunnel by a fixture.

FIG. 4 is a cross-sectional view taken along the line AA in FIG.

FIG. 5 is a cross-sectional view taken along the line BB in FIG. 3, showing a state of being cut.

FIG. 6 is a view showing a state in which the reinforcing material shown in FIG. 5 is embedded in a coating layer made of a cement-based wet fireproof spraying material to form a tunnel fireproof coating structure of the present invention.

7 is a diagram showing an example of a contact portion other than the contact portion shown in FIG.

FIG. 8 is a cross-sectional view showing an example of the tunnel fireproof coating structure of the present invention formed on the wall surface of the tunnel.

9 is a sectional view showing a partially enlarged view of the tunnel fireproof coating structure shown in FIG.

[Explanation of symbols]

1 Reinforcement material 2 body 3 abutment 3a slope part 3b Horizontal part 4 fixtures 4a anchor 4b washer 5 Cement-based wet fireproof material (coating layer) 6 vertical wire 7 Horizontal wire 8 Tunnel wall surface (construction surface) 9 concrete 10 Tunnel fireproof coating structure

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C04B 14:20) C04B 111: 28 111: 28 (72) Inventor Hiroyuki Obata 2-4-2 Daisaku Sakura City, Chiba Prefecture Pacific Ocean F-term in Central Research Laboratory of Cement Corporation (reference) 2D055 CA04 DB00 KB04 KB06 4G012 PA07 PA08 PA19 PC11 PC15 PE04

Claims (5)

[Claims] 1. A reinforcing member comprising an abutting portion fixed on a wall surface of a tunnel with a fixture and a mesh-shaped main body portion arranged apart from the wall surface of the tunnel in an uneven shape.
The drying shrinkage rate of 0.3% with which the wall surface of the tunnel is coated with a predetermined thickness so that the reinforcing material is embedded
A tunnel fire-resistant coating structure comprising the following cement-based wet fire-resistant spraying material, wherein the mesh-shaped main body of the reinforcing material is a wall thickness of the cement-based wet fire-resistant spraying material from the wall surface of the tunnel. A tunnel fireproof coating structure, wherein the tunnel fireproof coating structure is embedded at a position separated by a distance of 1/4 to 3/4 of a length. 2. The tunnel fireproof coating structure according to claim 1, wherein a diameter of a wire material constituting the mesh-shaped main body of the reinforcing material is 0.8 to 3.0 mm. 3. The tunnel fireproof coating structure according to claim 1, wherein the mesh-shaped main body of the reinforcing member is made of stainless steel and has an opening size of 20 to 120 mm. 4. The thickness of the coating layer made of the cement-based wet fire-resistant spray material is 20 to 80 mm.
The tunnel fireproof coating structure according to any one of items 1 to 3. 5. The cement-based wet fire-resistant spray material contains vermiculite and / or pearlite, and has a compressive strength of 1.5 MPa or more at 28 days of age, according to any one of claims 1 to 4. The described tunnel fireproof coating structure.