JP4066179B2 - Fireproof coating structure for cable conduit in tunnel - Google Patents

Description

  The present invention relates to a fireproof covering structure for a cable pipe installed on an inner wall of a tunnel for attaching an electric / communication cable in the tunnel.

Typically, the tunnel are installed cable ducts is, one or a plurality of electrical and communication cable is attached therein. The cable conduit Made up of a steel conduit or rigid polyvinyl chloride tube or the like, also, electrical and communication cables are widely used those which are covered by a plastic covering material such as vinyl chloride. When a fire, etc. occurs in a tunnel, there is no escape for heat because of the special environment in the tunnel, and the cable conduit is exposed to high temperature (1200 ° C or higher) in a short time, and the electricity installed inside and damage of the communication cable, there is likely to be a cause of serious trouble, such as cutting. Therefore, a protection box made of ceramic fireproof plates and rock wool has been developed to cut off the heat from fire. For example, a cable box attached to the inner wall of the tunnel is surrounded by a protection box to prevent heat from fire. Attempts have been made to block cable conduits.

  Further, Patent Document 1 discloses that a facility provided by using the inner wall of a tunnel is surrounded by a protective box having a fireproof plate structure and is cut off from the tunnel space, and is placed in the protective box at the time of a fire due to a vehicle accident or the like in the tunnel. A fireproof protection method for electrical / communication cables and the like in a tunnel characterized in that the propagated heat is released to the concrete housing side through a metal plate provided on the inner surface side of the protective box and in contact with the concrete housing side of the tunnel Is disclosed.

  Further, Patent Document 2 discloses a heat-resistant film (3a, 3b) that is bonded to the outer periphery of the cable protection tube (1) including the cable (2) and prevents passage of steam on one or both of the inner surface and the outer surface. The first heat insulating material layer (3) having the above and the heat absorption formed by incorporating water (10) made of a liquid or gel substance in the bag (11) formed on the outer periphery of the first heat insulating material layer (3). A communication cable protection tube comprising: a material (12); and a second heat insulating material layer (13) provided on an outer periphery of the endothermic material (12); An outdoor installation fireproof coating structure is disclosed.

Further, in Patent Document 3, the bottom 3 of the metal box 2 of the duct body 1 is covered with the bottom fireproof insulation coating material 4, and the side wall 5 of the box 2 is covered with the side fireproof insulation coating material 6. In the metal duct with a fireproof insulation coating, a spacer 9 molded into a predetermined shape with a flame retardant material is sandwiched between the joint portions 7 and 8 at the corners of the bottom fireproof insulation coating material 4 and the side fireproof insulation coating material 6. is deposited, the spacer 9, a vertical overlapping portion which rises along the inner surface 12 of the is connected to an upper surface 11 and the side insulating refractory coating material 6 of clamping portion 10 which is sandwiched between the joint portions 7, 8 A fireproof and heat insulating covering structure for a metal duct with a fireproof and heat insulating covering, characterized in that 13 is provided. Further, from the bottom of page 6 of Patent Document 3 to the 5th to the 7th page and the 3rd line, “all of the bottom fireproof thermal insulation coating material 4, the side fireproof thermal insulation coating material 6 and the upper fireproof thermal insulation coating material 16 are conventional. Mainly the same material as the refractory insulation coating material, that is, zonolite crystal, wollastonite crystal, tobermorite crystal, or a mixture thereof, and if necessary, contain reinforcing materials such as clay and fibrous materials. and, calcium silicate-based molding material or the like is used. "Ru More described effect.

  Furthermore, in Patent Document 4, as a calcium silicate material useful as a fireproof covering material for a tunnel structure, a calcium silicate material containing a matrix and a fiber made of calcium silicate hydrate, The calcium hydrate is composed of tobermorite and zonotlite, and the ratio of the X-ray diffraction intensity of the (001) plane of the zonotrite to the (002) plane of the tobermorite is 0.3 as the former / the latter. ˜5.0, and the calcium silicate material contains acicular wollastonite in the range of 20 to 60% by mass and cellulose pulp in the range of 1 to 10% by mass as the fiber at 1200 ° C. A calcium silicate material having a residual shrinkage ratio of 5% or less is disclosed.

  Further, in Patent Document 5, as a fireproof covering structure using an endothermic pack, a liquid or gel-like substance such as water or a polymer impregnated with water in a cell formed by partitioning between two films, etc. Wrap a heat-absorbing pack with a heat-absorbing material enclosed and heat-sealed around it, and a refractory heat insulating material such as an inorganic fiber mixed mat around the conduit to be refractory-coated, and use wire, tape, or wire mesh A fireproof covering structure for a conduit is disclosed which is fixed and covered with a metal plate as necessary.

  Further, Patent Document 6 discloses a coating material that is used by being wound around a pipe line, and the coating material is a flexible structure composed of a three-layer laminate structure of an aluminum cloth protective material, a noncombustible material, and a heat absorbing pack. A fireproof coating material characterized by being formed into a pouch-like sheet is disclosed.

JP, 2002-360722, A Claims Japanese Patent Application Laid-Open No. 11-46430 Japanese Utility Model No. Sho 63-139894 Specification for Utility Model Registration Page 6-7 JP, 2003-104769, A Claims Japanese Patent Application Laid-Open No. 7-135716 JP 9-280480 A Patent Claim

  Here, the RABT curve is adopted as the heating condition in the fire resistance test of the tunnel frame accompanying the recent tunnel construction methods such as submerged tunnels, and it is necessary to perform the same condition in the fire resistance test of the cable pipe installed in the tunnel. It has become. Since the softening temperature of the covering material used for the cable for electrical / communication attached to the cable conduit is usually about 85 ° C., the internal temperature of the cable conduit is set to 85 ° C. or less under the above heating conditions. Although it is necessary, the present situation is that the cable pipe fireproof coating structure that satisfies this condition has not yet been developed.

  Accordingly, an object of the present invention is to provide a fireproof covering structure for a cable conduit in a tunnel that can reduce the internal temperature of a cable conduit to 85 ° C or lower when a fireproof test is performed at 1200 ° C for 30 minutes based on the RABT curve. It is to provide.

Fireproof covering structure of the tunnel in the cable duct of the invention, a plurality of attached we are to the inner wall of the tunnel, one or a plurality of cable ducts and cable was attached or such cable conduit therein The collected cable conduit assembly is coated with an aluminum foil layer in contact with at least the outer peripheral surface and with a heat insulating mat material having a density of 24 to 48 kg / m ³ and a thickness of 15 to 50 mm. In the fireproof covering structure of the cable conduit in the tunnel in which the outside of the heat insulating mat material is surrounded and sealed by the fireproof covering material installed on the inner wall of the tunnel , the fireproof covering material is 0.8 to 1.1 g / cm ³ . and density and 15~50mm calcium silicate board layer having a thickness of, in the cell which are partitioned and formed by sealing the two films, impregnated with water or a water polymer A heat absorbing pack layer encapsulating become more liquid-like or gel-like endothermic material composed of a heat-absorbing pack layer having a moisture 4000~5000g / m ^2, the heat absorbing pack layer of the outer peripheral surface of the heat insulating mat member characterized by installed Tei Rukoto to face at an aluminum foil layer and spacing, in fire tests 30 minutes based rather 1200 ° C. in RABT curve, the internal temperature of the cable ducts is 85 ° C. or less And

Moreover, fire protection structure of the tunnel in the cable duct of the invention, a plurality attached to the inner wall of the tunnel, one or a plurality of cable ducts and cable was attached or such cable conduit therein A heat insulating mat member having an aluminum foil layer on one side and having a density of 24 to 48 kg / m ³ and a thickness of 15 to 50 mm is brought into contact with the collected cable conduit aggregate so that the aluminum foil layer does not contact. In the fireproof covering structure of the cable conduit in the tunnel, in which the outside of the heat insulating mat material is surrounded and sealed by the fireproof covering material installed on the inner wall of the tunnel , the fireproof covering material is 0.8 to 1.1 g / a calcium silicate plate layer having a density and thickness of 15~50mm of cm ^3, in the cells partitioned formed by sealing the two films, positive impregnated with water or water A heat absorbing pack layer encapsulating than become liquid-like or gel-like endothermic material mer composed of a heat-absorbing pack layer having a moisture 4000~5000g / m ^2, aluminum foil endothermic pack layer of the heat insulating mat member Ri by that is disposed so as to face at a layer and spacing, in fire tests 30 minutes based rather 1200 ° C. in RABT curve, wherein the internal temperature of the cable ducts is 85 ° C. or less And

Furthermore, the distance between the aluminum foil layer of the heat insulating mat material facing thereto and endothermic pack layer, it is desirable that 80-100 mm.

Also, calcium silicate plates which form a calcium silicate board layer, the matrix consists of the tobermorite and xonotlite, as fibers, containing 20 to 60 wt% of acicular wollastonite and 10% by weight of the cellulose pulp It is desirable .

According to the fireproof covering structure of the cable conduit in the tunnel of the present invention, the fireproof cover material surrounding and sealing the heat insulating mat member covering the cable conduit in the tunnel has a density of 0.8 to 1.1 g / cm ³ and It consists of a calcium silicate plate layer having a thickness of 15 to 50 mm and an endothermic pack layer having a water content of 4000 to 5000 g / m ² , and this endothermic pack layer is spaced from the aluminum foil on the outer peripheral surface of the heat insulating mat material. Since the heat-absorbing pack layer is damaged by heat and the water vapor generated in the space between the two is further improved in the effect of suppressing the temperature rise of cable pipes, etc., the existing fireproof coating be compared to the structure to reduce the volume occupied in the tunnel, during the fire in the tunnel, good never damage the electrical and communications cables that are attached to the cable conduit resistance - one in which there is an effect that exerts a thermal insulation performance.

  The fireproof covering structure for a cable conduit in a tunnel according to the present invention first comprises a heat insulating mat member on the outer periphery of a cable conduit or a plurality of cable conduit aggregates (hereinafter simply referred to as “cable conduit etc.”). The outer side of the aluminum foil is in contact with and covered with the outer side, and the outer side of the endothermic pack layer faces the aluminum foil layer with a fireproof coating material composed of the endothermic pack layer and the calcium silicate plate layer on the outer side. It is installed so as to surround the cable conduit and the like with the tunnel inner wall and the fireproof covering material, and to shut off the cable conduit and the inside of the tunnel.

  In the fireproof coating structure of the cable conduit in the tunnel of the present invention, the cable conduit attached to the inner wall of the tunnel is, for example, a steel conduit (JIS C8305), a hard vinyl chloride tube (JIS K6741), or an FRP (fiber reinforced plastic) tube. Etc. can be used. Further, the electric / communication cable attached to the cable conduit or the like is not particularly limited, and a known / conventional cable can be used. The number of electrical / communication cables attached to the cable conduit is not particularly limited, and may be one or plural. Further, the configuration of the plurality of cable conduits is not particularly limited, and the configuration of the plurality of cable conduits is not limited at all.

The outer periphery of the cable conduit or the like having the above-described configuration is covered with a heat insulating mat material, and the outer periphery thereof is covered with an aluminum foil layer. Here, the aluminum foil layer acts to prevent an endothermic pack, which will be described later, from being damaged by heat, and the internal moisture becomes water vapor to prevent direct contact with cable conduits, etc. It is important that the mat member is disposed on at least the outer peripheral surface. If the aluminum foil layer is disposed only on the inner peripheral surface of the heat insulating mat material, that is, the surface in contact with the cable conduit, the water vapor temperature directly propagates from the aluminum foil layer to the cable conduit, etc. This is not preferable because it leads to an increase in internal temperature. The density of the heat insulating mat is in the range of 24 to 48 kg / m ³ , preferably 30 to 40 kg / m ³ . Here, when the density is less than 24 kg / m ^3, it is not preferable because it may become non-uniform when covering a cable pipe or the like, and when the density exceeds 48 kg / m ³ , This is not preferable because the coating property is lowered and the coating operation is difficult to perform, and the coating may become non-uniform. The thickness of the heat insulating mat is 15 to 50 mm, preferably 20 to 40 mm, and most preferably 25 to 30 mm. If the thickness of the heat insulating mat is less than 15 mm, it is not preferable because the internal temperature of the cable conduit and the like easily rises when receiving heat, and if the thickness of the heat insulating mat exceeds 50 mm, This is not preferable because the volume of the fireproof covering structure in the space becomes too large. The material of the heat insulating mat is not particularly limited as long as it has heat insulating properties and flexibility and can be wound. For example, a mat or felt such as glass wool, rock wool, ceramic wool or the like is used. Glass wool is particularly preferred from the viewpoints of price and workability. The thickness of the aluminum foil layer is 4 to 20 μm, preferably 5 to 15 μm. Here, if the thickness of the aluminum foil layer is less than 4 μm, it is not preferable because the aluminum foil layer easily breaks during construction, and if the thickness of the aluminum foil layer exceeds 20 μm, the cost increases accordingly. It is not preferable because an improvement in fire resistance corresponding to that cannot be obtained.

  In addition, in the fireproof covering structure of the cable conduit in the tunnel of the present invention, the outer periphery of the cable conduit or the like is covered with a heat insulating mat material, and further, the outer periphery thereof is covered with an aluminum foil layer. Instead of the configuration, a heat insulating mat member having an aluminum foil layer on at least one surface can be covered with an outer periphery of a cable conduit or the like. In this case, in the heat insulating mat member having an aluminum foil layer on one side, it is important to cover the aluminum foil layer so as not to contact the outer periphery of the cable conduit or the like.

  A cable conduit or the like covered with the heat insulating mat material and the aluminum foil layer as described above or the heat insulating mat material provided with the aluminum foil layer on at least one surface is attached to the inner wall of the tunnel. The attachment method is not particularly limited, and various methods such as hanging from the upper part of the tunnel with an attachment installed on the inner wall of the tunnel or fixing with an attachment can be employed.

Next, a fireproof covering material is installed so as to surround the cable conduit covered with the heat insulating mat member attached to the inner wall of the tunnel, and the cable conduit is shut off from the inside of the tunnel. Here, the fireproof covering material used for the fireproof covering structure of the cable conduit in the tunnel of the present invention has a two-layer structure including an endothermic pack layer and a calcium silicate plate layer. The endothermic pack layer encloses an endothermic material made of a liquid or gel-like substance made of water or a polymer impregnated with water in a cell defined between two films, and the periphery is sealed by a method such as heat sealing. It has a sealed configuration. For example, the endothermic pack layer is water in a cell that is partitioned between two films formed by sandwiching an aluminum foil in a sandwich structure between two synthetic resin films such as nylon film and polyethylene film. Alternatively, a liquid such as a polymer impregnated with water or an endothermic material such as a gel-like substance is enclosed, and the surroundings are heat-sealed, for example, a 5 to 10 cm square pack, that is, a sheet in which cells are continuously installed Can be. Incidentally, the endothermic pack layer, 4000~5000g / ^{m 2,} preferably has a moisture 4300~4700g / ^{m 2.} When the moisture content of the endothermic pack layer is less than 4000 g / m ² , the endothermic effect is reduced, which is not preferable. When the moisture content of the endothermic pack layer exceeds 5000 g / m ² , the thickness of the endothermic pack layer increases. This is not preferable because the volume of the fireproof covering structure occupying the space in the tunnel is increased accordingly. Note that. Endothermic pack layer are those cells encapsulating water 30 g 0.99 per 1 m ² of (4500g / ^{m 2)} thickness 4.5mm is optimal.

The density of the calcium silicate plate constituting the calcium silicate board layer of fireproofing material, in 0.8~1.1g / cm ^3, preferably in the range of 0.9~1.05g / cm ³ is there. Here, when the density is less than 0.8 g / cm ^3, it is not preferable because it is easily damaged, and when the density exceeds 1.1 g / cm ³ , the heat insulation performance is deteriorated, which is not preferable. Furthermore, the thickness of the calcium silicate plate is in the range of 15-50 mm, preferably 20-40 mm, optimally 25-30 mm. Here, when the thickness is less than 15 mm, it is not preferable because fire resistance performance is lowered, and when the thickness exceeds 50 mm, it is preferable because the volume of the fireproof coating structure in the space in the tunnel becomes large. Absent. Although the calcium silicate plate is not particularly limited, for example, a matrix as described in Patent Document 4 is composed of tobermorite and zonotolite, and 20 to 60% by mass of acicular wollastonite and fibers are used. A calcium silicate plate containing 1 to 10% by mass of cellulose pulp can be suitably used.

  In addition, the lamination | stacking method of an endothermic pack layer and a calcium silicate board layer is not specifically limited, For example, it laminates | stacks by adhere | attaching both layers, or seals an endothermic pack layer to a calcium silicate board layer using a tucker. It can be laminated by attaching the parts.

Fireproofing material having the above-described configuration, the endothermic pack layer facing the attached cable ducts or the like to the tunnel inner wall, cut off and tunnel inner wall and areas I enclosed do this fireproofing material and tunnel interior It is installed on the inner wall of the tunnel. In addition, the method of installing the fireproof coating material is not particularly limited. For example, a steel base is installed on the inner wall of the tunnel, and the fireproof coating material can be attached to the steel base. Incidentally, seams of the seam and fireproofing material comrades tunnel inner wall and the refractory coating material is intended to seal with a sealing agent such as silicon sealant having a fireproof thermal insulation. Moreover, the joint portion of the length direction, attach the fireproof coating materials by installing steel ground to a joint portion, the joint portion is you construction by sealing using a sealing agent as described above.

  Further, when installing the fireproof covering material on the inner wall of the tunnel, the heat insulating mat material and the heat insulating mat material having the heat insulating mat material and the aluminum foil layer coated on the outer periphery of the cable pipe or the like, or the aluminum foil layer on at least one side, and the heat absorbing pack of the fireproof covering material It is preferable to attach the refractory coating material so as to have a certain distance, for example, a space within 100 mm without contacting the layer. Here, by providing a space, that is, by providing a space, it is possible to further enhance the effect of suppressing the temperature rise of the cable conduit or the like by the steam generated by the heat absorption pack layer being damaged by heat. Note that if the distance exceeds 100 mm, the volume of the fireproof covering structure occupying the space in the tunnel increases, which is not preferable.

  According to the fireproof covering structure of the cable conduit in the tunnel of the present invention having the above-described configuration, the time-temperature defined in the “Guideline for Road Tunnel Equipment and Operation (RABT)” of the German Federal Ministry of Transport Road Construction Bureau When a fire resistance test is performed at 1200 ° C. for 30 minutes based on the curve [RABT curve: FIG. 2], the internal temperature of the cable conduit or the like can be suppressed to 85 ° C. or less.

One embodiment of the fireproof covering structure for a cable conduit in a tunnel according to the present invention will be described with reference to FIG.
As an alternative to the tunnel inner wall, three rows of ALC plates (1) with a length of 1820 mm, a width of 600 mm, and a thickness of 100 mm are used, and two cable pipes (50A steel pipe) (2) are suspended on the lower side in the length direction. It was attached using the tool (3). One cable pipe (2) has an optical cable (covering material: vinyl chloride) (4), and the other cable pipe (2) has an electric cable (covering material: vinyl chloride) (5). Were attached to each.
Next, glass wool (aluminum foil thickness: 7 μm, glass wool density: 32 kg / m ³ , thickness: 25 mm) with two cable conduits (2) as an aggregate and an aluminum foil layer on one side on the outer periphery ( 6) was covered so that the aluminum foil layer did not contact the cable conduit (2).
Next, the fixture (9) is fixed to the ALC plate (1) with an ALC female screw plug (10), and the steel base (9) is composed of a heat absorption pack layer (7) and a calcium silicate plate (8). The dressing was fixed. The shortest distance between the endothermic pack layer (7) and the aluminum foil layer was 80 mm.
The endothermic pack layer (7) is formed by enclosing 30 g of water in a cell formed by partitioning between two films formed by sandwiching an aluminum foil between two nylon films in a sandwich structure. the one having 150 per 1 m ² of the heat-sealed cell (4500g / ^{m 2),} the thickness was of 4.5 mm.
The calcium silicate plate layer uses slaked lime as a calcareous raw material, and ferrosilicon dust having an Al ₂ O ₃ content of 0.5% by mass and an SiO ₂ content of 98% by mass as amorphous silicic acid as a siliceous raw material. , Powdered silica with an Al ₂ O ₃ content of 1% by mass as crystalline silicic acid, an SiO ₂ content of 98% by mass and a brane value of 3000 cm ² / g, an average fiber length of about 100 μm and an aspect ratio of about 10 Of acicular wollastonite and 200 ml of CSF beaten cellulose pulp, CaO / SiO ₂ mass ratio 1.05, amorphous silicic acid / crystalline silicic acid mass ratio 0.18, slaked lime 43.7% by mass, A raw material slurry having a composition of 5% by mass of ferrosilicon dust, 28.3% by mass of powdered silica, 20% by mass of acicular wollastonite, and 3% by mass of beaten cellulose pulp. Prepared, heat-cured at 90 ° C. for 2 hours, followed by pressure dehydration molding at a pressure of 4 MPa to form a cake, and the resulting cake was autoclaved at 195 ° C. for 10 hours to obtain a density of 1.0 The thickness is 25 mm. In addition, the ratio of X-ray diffraction intensity of the obtained silicate plate layer of zonotlite (001) plane / tobermorite (002) plane was 1.1.
The fireproof covering material was laminated by attaching the seal portion of the endothermic pack layer (7) having the above configuration to the calcium silicate plate layer (8) with a tacker.
Further, the joint between the ALC plate (1) and the fireproof coating material and the joint between the fireproof coating materials were sealed with a silicon sealing agent (11). In addition, the dimension of the height direction of the cross section of the obtained fireproof coating structure was 400 mm, and the dimension of the horizontal direction was 540 mm.

Both ends of the test body of the fireproof coating structure of the cable conduit in the tunnel having the above-described configuration are sealed with a fireproof material, and the end of the cable conduit (2) is filled with ceramic felt, and then the test body is tested. A central portion of 890 mm in the longitudinal direction is installed in a small horizontal furnace from above, and the temperature is raised from room temperature to 1200 ° C. in the first 5 minutes according to the RABT curve shown in FIG. The mixture was cooled to room temperature 140 minutes after the start of heating. The temperature data measured by the thermocouple (12) attached to the surface of the optical cable (4) and the electric cable (5) at the center in the length direction in the cable conduit (2) at this time is shown in FIG. . 3A shows the temperature of the surface of the optical cable (4), and FIG. 3B shows the temperature of the surface of the electric cable (5). As apparent from the data of FIG. 3, the maximum temperature of the cable surface is 78 ° C., and the fireproof covering structure of the cable pipe in the tunnel of the present invention has sufficient fireproofing and heat insulating performance.
When the inside of the refractory coating structure was investigated after the heating test was completed, it was observed that the individual cells of the endothermic pack layer in the zone heated in the small horizontal furnace were damaged.

  The fireproof coating structure of the cable conduit in the tunnel according to the present invention has a very excellent fireproof and heat insulation performance and can be installed by simple construction, as well as the existing tunnel cable conduit in addition to the new tunnel. It can be suitably employed as a fireproof coating structure.

1 shows one embodiment of a fireproof covering structure for a cable conduit in a tunnel of the present invention in an embodiment. It is a graph which shows a RABT curve. It is a graph which shows the data of the temperature change in a cable pipe line at the time of heating the test body of the fireproof coating structure of the cable pipe line in a tunnel shown in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ALC board 2 Cable pipe line 3 Suspension tool 4 Optical cable 5 Electric wire cable 6 Glass wool which has aluminum foil layer on one side 7 Endothermic pack layer 8 Calcium silicate board layer 9 Steel base 10 ALC female thread plug 11 Silicon sealing agent 12 Thermoelectric versus

Claims (4)

Attached to the inner wall of the tunnel, one or a plurality of cable ducts and cable was attached or such cable ducts a plurality of collected cables conduit assembly therein, an aluminum foil layer of at least the outer periphery the insulating mat material having a thickness of density of 24~48kg / m ³ and 15~50mm while being in contact with the coating on the surface coated contact, outside of the insulating mat material is placed on the inner wall of the tunnel fire in fire protection structure surrounds at the sealed tunnel cable ducts by dressing the refractory coating material, calcium silicate plate having a thickness of density and 15~50mm of 0.8~1.1g / cm ³ a layer, in the cell which are partitioned and formed by sealing the two films were sealed liquid or gel endothermic material made of polymer impregnated with water or water A thermal pack layer composed of a heat-absorbing pack layer having a moisture 4000~5000g / m ^2, the heat absorbing pack layer is disposed so as to face at a aluminum foil layer and the spacing of the outer peripheral surface of the heat insulating mat member by being in fire tests 30 minutes based rather 1200 ° C. in RABT curve, fire protection structure of the tunnel in a cable duct, wherein the internal temperature of the cable ducts is 85 ° C. or less. Attached to the inner wall of the tunnel, one or a plurality of cable ducts and cable was attached or such cable ducts a plurality of collected cables conduit assembly therein, an aluminum foil layer on one side A heat-insulating mat member having a density of 24 to 48 kg / m ³ and a thickness of 15 to 50 mm is coated so as not to contact the aluminum foil layer, and the outside of the heat-insulating mat member is installed on the inner wall of the tunnel in fire protection structure surrounds the fireproofing material sealed tunnel cable ducts for the refractory coating material, silica having a density and thickness of 15~50mm of 0.8~1.1g / cm ³ calcium plate layer, in the cell which are partitioned and formed by sealing the two films, liquid or gel endothermic material made of polymer impregnated with water or water A heat absorbing pack layers off to consist endothermic pack layer having a moisture 4000~5000g / m ^2, the heat absorbing pack layer is disposed so as to face at a aluminum foil layer and the spacing of the insulating mat material by it is, in fire tests 30 minutes based rather 1200 ° C. in RABT curve, fire protection structure of the tunnel in a cable duct, wherein the internal temperature of the cable ducts is 85 ° C. or less. The fireproof coating structure for a cable conduit in a tunnel according to claim 1 or 2 , wherein a distance between the heat absorption pack layer and the aluminum foil layer of the heat insulating mat material facing the heat absorption pack layer is 80 to 100 mm . The calcium silicate plate forming the calcium silicate plate layer is composed of tobermorite and zonotolite, and contains 20 to 60% by weight of acicular wollastonite and 1 to 10% by weight of cellulose pulp as fibers. However, the fireproof coating structure for a cable conduit in a tunnel according to claim 1 or 2 .

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