Metal form and movable arch center

Abstract

To provide a metal form and a movable arch center capable of improving quality of lining concrete.SOLUTION: A metal form 3 forming an installation space D1 of lining concrete C1 between an inner peripheral surface t1 of a tunnel T1 and itself, is provided with a thermal insulation film 6 formed on an exposed surface 31a of an inner pit side of the metal form 3, wherein the thermal insulation film 6 includes anticorrosive material 61 as a basis agent and thermal insulation material 62 as an additive agent, and the thermal insulation material 62 includes wood chips and fly ash. A movable arch center 1 provided with the metal form is also provided.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a metal formwork and a mobile center for pouring lining concrete. [Background technology]

[0002] Tunnel lining concrete is poured in designated sections using metal forms attached to a slide center that can move in the tunnel extension direction. The compressive strength of the poured concrete needs to be increased to prevent the concrete from cracking when it is removed from the form.

[0003] The applicant of this application has previously proposed a technology for obtaining a desired compressive strength by heating the lining concrete between the completion of pouring the lining concrete and its removal from the form (see Patent Document 1 below). The mobile center described in Patent Document 1 is equipped with a heater unit that heats the lining concrete. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-190594 Summary of the Invention [Problem to be solved by the invention]

[0005] When removing the formwork, peeling may occur on the inner surface of the lining concrete. Figure 15 is a schematic diagram showing an example of the inner surface of lining concrete where peeling has occurred. The peeling shown in Figure 15 can also occur when the lining concrete is heated. In order to improve the quality of the lining concrete, measures to prevent peeling of the lining concrete are desired.

[0006] The present invention has been made in consideration of the above circumstances, and its object is to provide a metal formwork and a mobile center that can further improve the quality of lining concrete. [Means for solving the problem]

[0007] (1) The metal formwork of the present invention is a metal formwork that forms a space for pouring lining concrete between itself and the inner surface of a tunnel, and comprises an outer frame that faces the inner surface of the tunnel, web plates that extend from both ends of the outer frame in the tunnel extension direction toward the inside of the tunnel, reinforcing members that are arranged circumferentially at intervals on the inside of the tunnel of the outer frame, extend in the tunnel extension direction, and are connected to the web plate on one end side and the web plate on the other end side, and an insulating coating film that is formed on the exposed surface of the outer frame on the inside of the tunnel, and the reinforcing members form a closed space between themselves and the outer frame.

[0008] With this configuration, the heat of the outer frame is insulated by the air in the closed space, and heat transfer to the reinforcing member can be suppressed. As a result, heat from the lining concrete is less likely to escape into the tunnel, and peeling of the lining concrete can be suppressed, further improving the quality of the lining concrete. In addition, because a heat-insulating coating is formed on the exposed surface of the outer frame on the tunnel side, where heat is more likely to escape, heat from the lining concrete is less likely to escape into the tunnel, further improving the quality of the lining concrete.

[0009] (2) The thermal barrier coating includes a rust-preventing material as a base and a thermal insulating material as an additive, and the thermal insulating material may include wood chips or fly ash.

[0010] Both wood chips and fly ash are by-products that, if not utilized, are disposed of as industrial waste. According to the present invention, wood chips and fly ash can be used as recycled resources for a new purpose (insulating material), thereby reducing the environmental impact and improving the insulating performance of metal forms. As a result, heat from the lining concrete is less likely to escape into the tunnel through the metal forms, further improving the quality of the lining concrete.

[0011] (3) The heat insulating coating may contain fly ash in a concentration of 40% by volume or more and 50% by volume or less relative to the rust preventing material.

[0012] Adding fly ash to the rust-preventive material at a concentration exceeding 50% by volume can impair the adhesion stability of the thermal insulation coating. On the other hand, in order to improve the thermal insulation performance, it is preferable to add the maximum amount of fly ash as a thermal insulation material within the range that provides good adhesion stability and other post-application conditions. According to the present invention, the fly ash is contained in the rust-preventive material at a concentration of 40% by volume or more and 50% by volume or less, thereby achieving higher thermal insulation performance while maintaining adhesion stability.

[0013] (4) The exposed surfaces may further comprise a plurality of heating elements arranged circumferentially with the reinforcing elements sandwiched therebetween, intermittently installed on the exposed surfaces, and heating the covering concrete through the outer frame; the insulating coating may be formed on a first region of the exposed surfaces where the heating elements are not installed, and on a second region of the exposed surfaces where the heating elements are installed, and may further comprise a rust-preventive coating containing a rust-preventive material as a base and not containing an insulating material as an additive or having a lower insulating material content than the insulating coating.

[0014] According to the present invention, by forming a heat insulating coating film intensively in areas where heat is likely to escape, it is possible to reduce the amount of heat insulating material used while ensuring the heat insulating properties of the metal formwork, thereby improving workability and reducing material costs for construction.

[0015] (5) The reinforcing member has a plurality of welds welded to the outer frame or the web plate, and the welds may not be formed in the portion of the reinforcing member that contacts both the outer frame and the web plate.

[0016] This configuration makes it more difficult for heat from the outer frame to be transferred to the web plate than before, preventing the lining concrete from peeling off, thereby further improving the quality of the lining concrete.

[0017] (6) The exposed surfaces may further comprise a plurality of heating elements arranged circumferentially with the reinforcing elements sandwiched therebetween, intermittently installed on the exposed surfaces, and heating the covering concrete through the outer frame, wherein a first circumferential end of the reinforcing element facing a first region of the exposed surfaces where the heating elements are not installed has a plurality of first welds welded to the outer frame, and a second circumferential end of the reinforcing element facing a second region of the exposed surfaces where the heating elements are installed has a plurality of second welds welded to the outer frame, and the shortest distance between the plurality of first welds and the web plate may be longer than the shortest distance between the plurality of second welds and the web plate.

[0018] According to the present invention, by separating the first welded portion, from the web plate, from which heat easily escapes, it is possible to prevent the first welded portion from concentrating in a position from which heat easily escapes. As a result, heat from the outer frame is less likely to be transmitted to the web plate than in the past, which makes it possible to suppress peeling of the lining concrete and further improve the quality of the lining concrete.

[0019] (7) The second welded portions may be formed at positions that do not overlap with the first welded portions in the circumferential direction.

[0020] This configuration allows the locations of the metal formwork that are prone to cooling (welding locations) to be dispersed, which prevents the lining concrete from peeling off and further improves the quality of the lining concrete.

[0021] (8) A sum of the lengths of the plurality of first welded portions in the tunnel extension direction may be shorter than a sum of the lengths of the plurality of second welded portions in the tunnel extension direction.

[0022] According to the present invention, it is possible to prevent heat from the outer frame from escaping to the reinforcing member via the first welded portion, through which heat can easily escape. Also, by increasing the total length of the second welded portion, through which heat cannot easily escape, it is possible to maintain the joining strength between the outer frame and the reinforcing member.

[0023] (9) The mobile center of the present invention is a mobile center with a total length of 10.5 m, in which the length of any of the metal formworks described in (1) to (8) in the tunnel extension direction is 2.1 m and five of the metal formworks are connected in the tunnel extension direction.

[0024] By using a 5-span, 2.1m mobile center, the number of web plates is reduced compared to the conventional 7-span, 1.5m mobile center, which reduces the amount of heat that escapes from the heated lining concrete through the web plates. As a result, the reduction in the number of web plates suppresses the peeling of the lining concrete when it is removed from the form, which further improves the quality of the lining concrete.

[0025] (10) The metal formwork of the present invention is a metal formwork that forms a space for pouring lining concrete between itself and the inner surface of a tunnel, and is provided with an insulating coating film formed on the exposed surface of the metal formwork inside the tunnel, the insulating coating film containing a rust-preventing material as a base and an insulating material as an additive, and the insulating material containing wood chips or fly ash.

[0026] By forming a heat-insulating coating on the exposed surface of the outer frame on the inside of the tunnel, where heat is likely to escape, heat from the lining concrete is less likely to escape into the tunnel, further improving the quality of the lining concrete. Furthermore, wood chips and fly ash are both by-products, and if not utilized, they are discarded as industrial waste. According to the present invention, wood chips and fly ash can be used as recycled resources for new applications (insulating materials), thereby reducing the environmental impact and improving the insulating performance of metal formwork. [Effects of the Invention]

[0027] According to the present invention, the quality of the lining concrete can be further improved. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a diagram showing the overall configuration of a lining concrete construction system according to an embodiment. FIG. [Figure 2] FIG. 2 is a front view of the slide center according to the embodiment. [Figure 3] 3 is a cross-sectional view of the slide center taken along line III in FIG. 2. [Figure 4] 1 is a perspective view of a portion of a side of a metal formwork according to an embodiment, viewed obliquely from above. [Figure 5] 5 is a cross-sectional view of the side of the metal formwork taken along the cutting line V in FIG. 4. [Figure 6] FIG. 1 is a schematic diagram showing an experimental example of a heat insulating coating film. [Figure 7] 1 is a table showing the coating films used in the experiment. [Figure 8] 10 is a graph showing experimental results. [Figure 9] This is a side view of a portion of the side of the metal formwork of the embodiment, seen from inside the tunnel. [Figure 10] This is a side view of a portion of the side of a metal formwork according to a comparative example, viewed from inside the tunnel. [Figure 11] 10A and 10B are diagrams showing a reinforcing member according to a modified example. [Figure 12]10A and 10B are diagrams showing a reinforcing member according to a modified example. [Figure 13] FIG. 10 is a diagram showing a metal formwork according to a modified example. [Figure 14] FIG. 10 is a schematic diagram showing the divided formwork loaded onto a truck. [Figure 15] FIG. 2 is a schematic diagram showing an example of the inner peripheral surface of lining concrete where peeling has occurred. DETAILED DESCRIPTION OF THE INVENTION

[0029] [Causes and solutions for peeling] The present inventors have conducted extensive research into measures to prevent the peeling of lining concrete, as shown in Fig. 15. In the process, they discovered that the peeling is particularly likely to occur during construction in winter.

[0030] The inventor also discovered that there are three types of peeling marks: a first peeling mark A1 that extends circumferentially as shown in Figure 15; a second peeling mark A2 that extends from the first peeling mark A1 in the tunnel extension direction; and a third peeling mark A3 that is located at various points on an imaginary extension line of the second peeling mark A2, and that the positions at which these marks are formed correspond to the positions of the web panel, the reinforcing member, and the position where the reinforcing member and the outer frame are welded, among the components of the formwork, respectively.

[0031] Based on this, the inventors have concluded that the cause of the peeling of the lining concrete during formwork removal is that the heat of the lining concrete is locally cooled by the formwork, resulting in the lining concrete not being heated sufficiently. For this reason, the inventors propose an invention in this application that improves the thermal insulation performance of the formwork. According to this invention, the peeling of the lining concrete during formwork removal can be suppressed, thereby further improving the quality of the lining concrete.

[0032] Specifically, in the present invention, the heat insulating performance of the formwork is improved by the following measures. (1) Increase the span length of the formwork to reduce the number of web panels. (2) Reduce the contact area between the outer frame and the reinforcing member, and create a closed space between the outer frame and the reinforcing member. (3) Form an insulating coating on the exposed surface of the outer frame inside the tunnel. (4) The welding positions of the reinforcing members are arranged so that they are not concentrated in areas where heat can easily escape.

[0033] Hereinafter, an embodiment including all of the above measures (1) to (4) will be described with reference to the drawings. Note that, in the present invention, it is sufficient to implement at least one of the above measures (1) to (4), and it is not essential to include all of them.

[0034] [Overall system configuration] Figure 1 is a diagram showing the overall configuration of a lining concrete construction system according to an embodiment of the present invention. The construction system is a system for constructing secondary lining concrete C1 (hereinafter also simply referred to as "lining concrete C1") on the inner circumferential surface (inner wall) t1 of a tunnel T1 that has been primarily lined. The construction system includes a slide center 1 (mobile center) for pouring the lining concrete C1, and multiple curing devices 10 for curing the lining concrete C1 poured by the slide center 1.

[0035] The slide center 1 and curing device 10 can travel on rails R1 laid on the floor of the tunnel T1. The slide center 1 pours lining concrete C1 sequentially at a predetermined span from the tunnel entrance side toward the face side (in the direction of the arrow in Figure 1). The curing device 10 sequentially cures the poured lining concrete C1 at a predetermined span.

[0036] [Configuration of slide center] FIG. 2 is a front view of the slide center 1. FIG. FIG. 3 is a cross-sectional view of the slide center 1 taken along the line III in FIG. 2 and 3, in order to simplify the drawings, a heating member 5 and a heat insulating coating 6, which will be described later, are omitted. Also, in Fig. 3, a reinforcing member 33, which will be described later, is omitted.

[0037] The slide center 1 is equipped with a gate-shaped bogie 2 that can travel within the tunnel T1 and a plurality of metal formwork 3 (hereinafter simply referred to as "formwork 3") that serves as a barrier plate for molding the inner surface of the lining concrete C1.

[0038] The gantry cart 2 includes a base 2a and a plurality of support pillars 2b that support the base 2a. Wheels 2c that engage with rails R1 laid on the floor of the tunnel T1 are provided at the lower ends of the support pillars 2b, and the gantry cart 2 travels within the tunnel T1 as the wheels 2c roll along the rails R1.

[0039] The formwork 3 has an arc-shaped cross section that roughly follows the inner circumferential surface t1 of the tunnel T1, and forms a pouring space D1 between itself and the inner circumferential surface t1 of the tunnel T1 for pouring the lining concrete C1. The formwork 3 is also called a center form. As shown in Figure 2, the formwork 3 has a top end 3a that covers the crown of the inner circumferential surface t1, side portions 3b that are rotatably connected to both ends of the top end 3a and cover the upper part of the side wall of the inner circumferential surface t1, and a bottom end 3c that is rotatably connected to the lower end of the side portion 3b and cover the lower part of the side wall of the inner circumferential surface t1.

[0040] The top end 3a is supported so as to be movable up and down by a plurality of jacks 41 provided on the base 2a of the gantry truck 2. The side end 3b and the bottom end 3c are supported so as to be rotatable in the width direction by a plurality of jacks 42, 43 provided on the outer surfaces of the support pillars 2b. The top end 3a, the side end 3b, and the bottom end 3c each have a pouring port (not shown) for pouring ready-mixed concrete into the pouring space D1.

[0041] Please refer to Figure 3. In this embodiment, a slide center 1 with a standard length of 10.5 m is constructed by connecting multiple formwork 3 in the tunnel extension direction. Here, in a conventional slide center (for example, Figure 3 of JP 2011-190594 A), when a standard length of 10.5 m is adopted, the formwork is divided into seven parts in the tunnel extension direction, and the length of each formwork in the tunnel extension direction (i.e., the span length) is 1.5 m, resulting in a "7 span 1.5 m" formwork.

[0042] In contrast, in this embodiment, five formworks 3 with a span length of 2.1 m are joined together to form a slide center 1 with a total length of 10.5 m. In other words, the slide center 1 of this embodiment has five spans of 2.1 m, two spans less than the conventional type. With this configuration, the number of web plates 32 (described below) is fewer than in the conventional type, and the amount of heat escaping from the heated lining concrete C1 through the web plates 32 can be reduced.

[0043] As a result, peeling of the lining concrete during form removal is suppressed in accordance with the reduction in the number of web plates 32, and the number of first peeling marks A1 in Figure 15 is reduced. This makes it possible to further improve the quality of the lining concrete C1.

[0044] Furthermore, by configuring the slide center 1 to be two spans shorter than the conventional type, the number of trucks required to transport the formwork 3 can be reduced, thereby reducing transportation costs.

[0045] FIG. 14 is a schematic diagram showing the divided formwork loaded onto a truck. Figure 14 (a) and (b) are a plan view and a side view showing a portion of a formwork 3 (two side sections 3b are shown in the figure) with a span length of 2.1 m loaded onto the loading platform B1 of a truck Tr1. The portion of the formwork 3 is secured to the truck Tr1 in an upright position, for example, with the tunnel extension direction facing vertically. Securement is similar to that for a conventional span length of 1.5 m.

[0046] Truck Tr1 is, for example, a 10-ton truck, and the height of the loading platform B1 is approximately 1.5 m from the ground. In principle, the loading height of a truck is regulated to 3.8 m or less, and since a span length of 2.1 m falls within this regulated height, truck Tr1 can be used to transport the divided formwork 3 from the factory to tunnel T1.

[0047] If the number of spans is four or less, the span length will be 2.6 m or more (10.5 ÷ 4 = 2.625), and the loading height will be 4.1 m or more (1.5 + 2.625 = 4.125 m), exceeding the regulated height and potentially causing problems in transporting the formwork 3. For this reason, five spans is particularly suitable, as this is the maximum span length that can be transported by truck. However, if the transportation problem can be solved, the present invention may employ a number of spans of four or less, or six spans.

[0048] Furthermore, by configuring the slide center 1 to have two fewer spans than the conventional type, the number of parts in the slide center 1 is fewer than before, which reduces the manufacturing cost of the slide center 1 and shortens the time required to assemble and disassemble the slide center 1. For example, in the case of a slide center with 7 spans and 1.5 m, it takes, for example, 9 trucks to transport it, 6 days to assemble it, and 4 days to disassemble it, but in the case of a slide center 1 with 5 spans and 2.1 m, it takes, for example, 7 trucks to transport it, 5 days to assemble it, and 3 days to disassemble it.

[0049] [Formwork configuration] 4 is a perspective view of a portion of the side portion 3b of the formwork 3, viewed obliquely from above. The following describes the side portion 3b of the formwork 3 as a representative example, and the other portions of the formwork 3 (top end portion 3a and bottom end portion 3c) have the same configuration as the side portion 3b, so description thereof will be omitted. The side portion 3b of the formwork 3 comprises an outer frame 31, a pair of web panels 32, and a plurality of reinforcing members 33 (for example, seven).

[0050] The outer frame 31 is a metal (for example, steel) plate material that extends in the tunnel extension direction and circumferential direction, and faces the inner circumferential surface t1 of the tunnel T1 when the lining concrete C1 is poured.

[0051] The web plates 32 are metal (for example, steel) plates extending into the tunnel from both ends of the outer frame 31 in the tunnel extension direction. The web plates 32 have the function of supporting the outer frame 31 and are also called webs.

[0052] The reinforcing members 33 are metal (e.g., steel) members that reinforce the tunnel-side surface of the outer frame 31, and are also called stiffeners. The reinforcing members 33 are provided on the tunnel-side surface of the outer frame 31, extend in the tunnel extension direction, and are connected to the web plate 32 on one end side and the web plate 32 on the other end side. A plurality of the reinforcing members 33 are lined up at intervals in the circumferential direction on the tunnel-side surface of the outer frame 31.

[0053] Figure 5 is a cross-sectional view of the side portion 3b of the formwork 3 taken along the cutting line V in Figure 4. The reinforcing member 33 has a trapezoidal cross section and forms a closed space S1 between it and the outer frame 31. The reinforcing member 33 has a first wall portion 33a extending from the outer frame 31 toward the inside of the tunnel, a second wall portion 33b circumferentially adjacent to the first wall portion 33a and extending from the outer frame 31 toward the inside of the tunnel, and a third wall portion 33c connected to the first wall portion 33a and the second wall portion 33b and facing the outer frame 31 with a gap between them.

[0054] The surface of the outer frame 31 facing the inside of the tunnel includes an exposed surface 31a that is exposed inside the tunnel, and a covered surface 31b that forms a closed space S1 by being covered with reinforcing members 33. A plurality of exposed surfaces 31a are lined up in the circumferential direction with reinforcing members 33 sandwiched between them. In the case of the side portion 3b of this embodiment, eight exposed surfaces 31a are lined up in the circumferential direction with seven reinforcing members 33 sandwiched between them.

[0055] As shown by the second peeling marks A2 in Figure 15, heat from the lining concrete C1 tends to escape toward the inside of the tunnel from the area where the outer frame and the reinforcing member are connected. In this embodiment, by making the cross-sectional shape of the reinforcing member 33 a hollow structure, the contact area between the outer frame 31 and the reinforcing member 33 can be reduced compared to when a reinforcing member with a solid structure is used. This makes it possible to prevent heat from the lining concrete C1 from escaping toward the inside of the tunnel through the outer frame 31 and the reinforcing member 33.

[0056] Furthermore, because a closed space S1 is formed between the outer frame 31 and the reinforcing member 33, the heat from the covering surface 31b of the outer frame 31 is insulated by the air in the closed space S1, further suppressing the heat transfer to the reinforcing member 33. As a result, it becomes difficult for the heat from the lining concrete C1 to escape into the tunnel, suppressing the occurrence of the second peeling marks A2 in Figure 15. This further improves the quality of the lining concrete C1.

[0057] [About the heating element] See Figures 4 and 5. The side portion 3b of the formwork 3 further includes a plurality of heating members 5. The heating members 5 are installed intermittently on the plurality of exposed surfaces 31a. In this embodiment, the heating members 5 are installed on every other one of the plurality of exposed surfaces 31a. Note that the heating members 5 only need to be installed intermittently on at least some of the exposed surfaces 31a, and may also be installed continuously on a plurality of exposed surfaces 31a adjacent in the circumferential direction.

[0058] As shown in Figure 4, the heating member 5 has a planar heating element 51 that generates heat when electricity is applied, and an electric wire 52 that supplies power to the heating element 51. The electric wire 52 passes through a through-hole 32a in the tunnel extension direction of the web plate 32 and is connected to a power source (not shown). The heating member 5 heats the lining concrete C1 through the outer frame 31 when the lining concrete C1 is poured, thereby allowing the lining concrete C1 to obtain a predetermined compressive strength.

[0059] The heating member 5 may have a pipe through which a heat medium such as a liquid (water, oil, etc.) circulates, instead of the heating element 51 and the electric wire 52. In this case, the heat medium is heated by a heating device such as a boiler and pressure-fed to the pipe by a pump.

[0060] By installing the heating elements 5 intermittently, the number of heating elements 5 can be reduced. This reduces the cost of the elements and the energy cost for operating the heating elements 5. On the other hand, installing the heating elements 5 intermittently makes it easier for heat from the lining concrete C1 to escape to the inside of the tunnel from the exposed surface 31a where the heating elements 5 are not installed. For this reason, in this embodiment, a heat insulating coating 6 (described later) is provided on the exposed surface 31a, thereby allowing more heat to remain within the lining concrete C1.

[0061] [About the heat-insulating coating] Referring to Figure 5, the side portion 3b of the formwork 3 is further provided with a thermal insulating coating 6. The thermal insulating coating 6 is formed on the entire surface of the side portion 3b inside the tunnel, including the exposed surface 31a of the outer frame 31. The thermal insulating coating 6 contains a rust prevention material 61 as a base and a thermal insulating material 62 as an additive.

[0062] The rust-preventing material 61 is a known rust-preventing paint, for example, "Quick-drying Rust-Preventing Eco" manufactured by Nippon Paint Co., Ltd.

[0063] The insulating material 62 includes, for example, wood chips or fly ash. However, the insulating material 62 is not limited to these and may include other insulating materials. As the insulating material, for example, a material having a particle size of several tens of μm to several hundreds of μm and a hollow or porous structure is preferable. As the other insulating material, for example, hollow glass beads may be included.

[0064] When fly ash is used as the insulating material 62, the insulating coating 6 contains fly ash at a concentration of, for example, 40% by volume or more and 50% by volume or less. That is, the insulating material 62 is added so that the volume of the insulating material 62 is about 70 to 90 parts by volume per 100 parts by volume of the rust preventive material 61.

[0065] Adding fly ash to the rust preventive material 61 at a concentration exceeding 50% by volume can impair the adhesion stability of the thermal insulation coating 6 (for example, the thermal insulation coating 6 becomes more susceptible to peeling). On the other hand, in order to improve the thermal insulation performance, it is preferable to add the maximum amount of fly ash as the thermal insulation material 62 within a range that provides good post-application conditions such as adhesion stability, and in this embodiment, a concentration of around 50% by volume is more preferable. However, as long as the post-application conditions are good, fly ash may be added to the rust preventive material 61 at a concentration exceeding 50% by volume.

[0066] Wood chips are, for example, powdered "sawdust" or "sawdust" that is generated when cutting wood. The grain size of wood chips is, for example, about 200 μm. Wood chips have traditionally been used as cushioning material for transported goods and as bedding for livestock. However, the present inventors have focused on the insulating properties of wood and have come up with the novel idea of ​​adding wood chips as an insulating material 62 to a rust prevention material 61.

[0067] Fly ash is fine ash particles generated when coal is burned in coal-fired power plants and the like. The particle size of fly ash is, for example, approximately 10 μm to 100 μm. Fly ash has traditionally been used as a concrete additive to impart strength and fluidity to concrete. However, the present inventors have focused on the fact that fly ash is porous and has insulating properties, and have come up with the novel idea of ​​adding fly ash to a rust prevention material 61 as an insulating material 62.

[0068] Both wood chips and fly ash are by-products that, if not utilized, would be disposed of as industrial waste. With the thermal insulation coating 6 of this embodiment, wood chips and fly ash can be used as recycled resources for new applications (thermal insulation materials), thereby reducing the environmental impact and improving the thermal insulation performance of the formwork 3. As a result, heat from the lining concrete C1 is less likely to escape into the tunnel through the formwork 3, further improving the quality of the lining concrete C1.

[0069] [Experimental example of heat insulating coating] In order to confirm the effect of using wood chips or fly ash as the heat insulating material 62 of the thermal barrier coating 6, the inventors conducted the following experiment.

[0070] Figure 6 is a schematic diagram showing an experimental example of thermal insulating coatings. Five samples were prepared by applying five different coatings X1 to X5 to one side of a 6 mm thick steel piece Y1, and attaching a heat source H1 (resistance heater) to the other side of the steel piece Y1. Three temperature sensors P1 to P3 were installed on top of the coatings X1 to X5. Sensor P1 was installed directly behind the heat source H1, sensor P2 was installed 7 cm from the center of sensor P1, and sensor P3 was installed 10 cm from the center of sensor P2.

[0071] The temperature of heat source H1 was set to 60°C, and the heat transferred from heat source H1 to sensors P1 to P3 via steel Y1 and coatings X1 to X5 was measured. This allows the heat escaping from heated lining concrete C1 (simulated by heat source H1) to the inside of the tunnel via the outer frame 31 (simulated by steel Y1) and thermal insulating coating 6 (simulated by coatings X1 to X5) to be evaluated based on the temperatures measured by sensors P1 to P3.

[0072] FIG. 7 is a table showing the coatings used in the experiment. Coating X1 is a simple anti-rust coating containing a rust-preventive material as a base material and no heat-insulating material as an additive, and is a reference example for this experiment. The rust-preventive material used was "Quick-drying Rust Preventive Eco" manufactured by Nippon Paint Co., Ltd. The same rust-preventive material as coating X1 was used as the base material for coatings X2 to X4.

[0073] Coating X2 contains a rust-preventive material as a base and wood chips as an additive. The wood chips were added in an amount of about 50 parts by volume per 100 parts by volume of the rust-preventive material (a concentration of about 33% by volume).

[0074] Coating X3 contains a rust-preventive material as a base and fly ash as an additive. The fly ash was added in an amount of about 80 parts by volume to 100 parts by volume of the rust-preventive material (a concentration of about 44% by volume).

[0075] Coating X4 contains a rust-preventive material as the base material and "Heat Cut Powder" manufactured by Toa System Create Co., Ltd. as an additive. The volume of Heat Cut Powder was added so that it was approximately 80 parts by volume for every 100 parts by volume of rust-preventive material (approximately 44% by volume concentration). Heat Cut Powder is a ceramic powder that has traditionally been used as an additive for thermal insulation purposes, so it was prepared as a comparative example.

[0076] Coating X5 is "Heat Insulation Coat" manufactured by Higashi Nippon Paint Co., Ltd. Heat Insulation Coat is a heat insulating paint in which heat insulating pigments and the like are added to acrylic silicone resin, and was prepared as a comparative example.

[0077] Coating films X1 to X4 were each formed by a single spray application, while coating film X5 was formed by spray application three times with an interval between each coat, in accordance with the specifications.

[0078] The film thickness of coatings X1 to X5 was measured using a paint film thickness gauge. The film thickness of coating X1 was 100 μm, and the film thicknesses of coatings X2, X3, and X4 were 412 μm, 373 μm, and 508 μm, respectively. Coatings X2, X3, and X4 were thicker than coating X1 because granular additives measuring several tens to several hundreds of μm were added to the rust prevention material. Coating X5 had a film thickness of 983 μm, the thickest due to the multiple coats.

[0079] Figure 8 is a graph showing the results of the experiment. The horizontal axis of the graph represents the time [minutes] elapsed since the start of heating with heat source H1, and the vertical axis of the graph represents the temperature [°C]. The upper group of lines on the graph represents the temperatures measured by sensor P1, the middle group of lines on the graph represents the temperatures measured by sensor P2, and the lower group of lines on the graph represents the temperatures measured by sensor P3. The tendency that the temperature measured by sensor P1, which is closest to heat source H1, is the highest and the temperature measured by sensor P3, which is farthest from heat source H1, is the lowest is common to all of the coatings X1 to X5.

[0080] Here, we focus on the temperature difference (Tp1-Tp3) between the temperature Tp1 measured by sensor P1 and the temperature Tp3 measured by sensor P3 at a predetermined elapsed time. This temperature difference is represented on the graph by, for example, arrow AR1. The larger this temperature difference, the less heat is transferred to sensor P3, indicating a higher thermal insulation performance of the coating. The temperature difference at 25 minutes elapsed is shown in the right column of the table in Figure 7.

[0081] As shown in Figure 7, the temperature difference was 17.8°C for the reference example coating film X1 (rust-preventive coating film), 20.6°C for coating film X2 (wood chips), and 22.3°C for coating film X3 (fly ash). Both wood chips and fly ash provided higher thermal insulation performance than the reference examples.

[0082] Furthermore, the temperature difference between coating films X2 and X3 was higher than that of comparative coating film X4 (heat cut powder), which was 16.0°C, and that of coating film X5, which was 17.8°C. It was confirmed that coating films X2 and X3 have higher heat insulating performance than coating films X4 and X5, which have traditionally been used as heat insulating materials. As described above, the heat insulating coating 6, which is based on the rust prevention material 61 and to which wood chips or fly ash is added as the heat insulating material 62, has favorable heat insulating properties.

[0083] [Regarding welding positions of reinforcing members] FIG. 9 is a side view of a part of the side portion 3b of the formwork 3 as seen from inside the tunnel. FIG. 10 is a schematic diagram illustrating a comparative example of the welding position. The welding positions of the reinforcing member 33 will be described below with reference to FIGS.

[0084] First, a comparative example of welding positions will be described. Fig. 10(a) is a view of side portion 3b according to the comparative example in the same cross section as Fig. 5, and Fig. 10(b) is a view of side portion 3b according to the comparative example from the same direction as Fig. 9. In the comparative example, reinforcing member 33 is tap-welded to web plate 32 by a plurality of welds 81a, 81b, and 81c (also simply referred to as "welds 81"), and is tap-welded to outer frame 31 by a plurality of welds 82 and 83.

[0085] More specifically, the weld 81a is formed in a portion where the first wall portion 33a of the reinforcing member 33 contacts both the outer frame 31 and the web plate 32 (i.e., the corner of the reinforcing member 33 on the outer frame 31 side). By welding the position where three or more members contact in this way, the reinforcing member 33 can be fixed to both the outer frame 31 and the web plate 32, so a weld is usually formed in this position.

[0086] Similarly, the welded portion 81b is formed at a portion where the second wall portion 33b of the reinforcing member 33 contacts both the outer frame 31 and the web plate 32. The welded portion 81c is formed at a portion where the third wall portion 33c of the reinforcing member 33 contacts the web plate 32.

[0087] The multiple welds 82 are formed at predetermined intervals in a portion where the first wall portion 33a of the reinforcing member 33 contacts the outer frame 31. The multiple welds 83 are formed at predetermined intervals in a portion where the second wall portion 33b of the reinforcing member 33 contacts the outer frame 31. Normally, the welds 82 and the welds 83 are formed at the same intervals, and as shown in Figure 10(b), the welds 82 and the welds 83 overlap in the circumferential direction.

[0088] Because the reinforcing members 33 are integrated with the outer frame 31 and web plate 32 at the welded joints 81 to 83, heat from the outer frame 31 and web plate 32 is easily transferred from the welded joints 81 to 83 to the reinforcing members 33. In other words, the formwork 3 is particularly susceptible to cooling at the welded joints 81 to 83, which causes the second peeling marks A2 and third peeling marks A3 in Figure 15 to be formed.

[0089] Therefore, in this embodiment, the positions at which the welds of the reinforcing members 33 are provided are devised so that the welds are not concentrated in positions where heat is likely to escape, thereby suppressing peeling of the lining concrete C1.

[0090] Specifically, the concentration of welds in positions where heat is likely to escape is avoided by the following measures A to D. Note that although this embodiment includes all of measures A to D, the present invention requires that at least one of measures A to D be implemented, and it is not essential to include all of them.

[0091] [Measure A: Place the weld away from the point where the reinforcing member, web plate, and outer frame come into contact] Refer to the enlarged view of Figure 5. The reinforcing member 33 of this embodiment is tap-welded to the web plate 32 by a plurality of welds 71a, 71b (also simply referred to as "welds 71"). The welds 71a are formed at and near the corner where the first wall portion 33a and the third wall portion 33c connect, and the welds 71b are formed at and near the corner where the second wall portion 33b and the third wall portion 33c connect. The welds 71a, 71b are located away from the outer frame 31. In other words, no welds 71 ​​are formed in the portion of the reinforcing member 33 that contacts both the outer frame 31 and the web plate 32.

[0092] Because the web plate 32 is a steel member that extends into the tunnel, it functions like a heat dissipation fin in the formwork 3, and tends to release heat from the lining concrete C1 into the tunnel. With conventional welding methods, as shown in Figure 10, welding is performed on the parts of the reinforcing member 33 that come into contact with both the outer frame 31 and the web plate 32, so heat from the outer frame 31 is easily transferred to the web plate 32 via the welded parts 81a and 81b, which is thought to be one of the causes of the second peeling marks A2 in Figure 15.

[0093] In contrast, the welded portion 71 in this embodiment is not formed in the portion of the reinforcing member 33 that contacts both the outer frame 31 and the web plate 32. This makes it more difficult for heat from the outer frame 31 to be transferred to the web plate 32 than in the past, thereby suppressing the occurrence of the second peeling marks A2. This further improves the quality of the lining concrete C1.

[0094] [Measure B: Arrange the welds in a staggered pattern] See Fig. 9. The reinforcing member 33 of this embodiment is tap-welded to the outer frame 31 at predetermined intervals by a plurality of welds 72 (first welds) formed on the first wall portion 33a and a plurality of welds 73 (second welds) formed on the second wall portion 33b. The plurality of welds 73 are formed in positions that do not overlap with the plurality of welds 72 in the circumferential direction. In other words, when viewed in the tunnel extension direction, the welds 72 are located between two adjacent welds 73, and the welds 72, 73 are arranged in a staggered pattern (alternately).

[0095] In the example of Figure 10, welded parts 82 and 83, which tend to cool easily, overlap in the circumferential direction, so that positions on the formwork 3 that tend to cool easily are concentrated when viewed in the tunnel extension direction, as indicated by arrow AR2 in Figure 10. This concentration of welded positions is thought to be one of the causes of the third peeling marks A3 in Figure 15.

[0096] In contrast, in this embodiment, the welded portions 72, 73 are arranged in a staggered pattern, so that the positions (welded positions) that are prone to cooling of the formwork 3 are dispersed. This makes it possible to suppress the occurrence of the third peeling marks A3, and further improve the quality of the lining concrete C1.

[0097] [Measure C: Place the second welded part farther from the web plate than the first welded part] As described above, the heating members 5 in this embodiment are installed intermittently on the exposed surfaces 31a arranged in the circumferential direction. Here, the area of ​​the exposed surface 31a where the heating members 5 are not installed is referred to as the "first area Z1," and the area of ​​the exposed surface 31a where the heating members 5 are installed is referred to as the "second area Z2." The first wall portion 33a (first end) of the reinforcing member 33 faces the first area Z1, and the second wall portion 33b (second end) of the reinforcing member 33 faces the second area Z2.

[0098] Because no heating element 5 is installed in the first region Z1, the temperature of the first region Z1 becomes lower than that of the lining concrete C1 while the lining concrete C1 is being heated, and the heat of the lining concrete C1 easily escapes from the first region Z1 to the inside of the tunnel. On the other hand, because a heating element 5 is installed in the second region Z2, the temperature of the second region Z2 becomes higher than that of the lining concrete C1 while the lining concrete C1 is being heated, and the heat of the lining concrete C1 does not easily escape from the second region Z2 to the inside of the tunnel.

[0099] As shown in FIG. 9, the shortest distance between the multiple welds 72 formed on the first wall portion 33a and the web plate 32 on one side in the tunnel extension direction (for example, the web plate 32 on the right side in FIG. 9) is referred to as the "shortest distance L1." The welds 72 connect the first region Z1, where the heating member 5 is not installed, to the reinforcing member 33, and therefore can be considered to be welds (first welds) from which heat easily escapes. Furthermore, the shortest distance between the multiple welds 73 formed on the second wall portion 33b and the web plate 32 on one side in the tunnel extension direction is referred to as the "shortest distance L2." The welds 73 connect the second region Z2, where the heating member 5 is installed, to the reinforcing member 33, and therefore can be considered to be welds (second welds) from which heat does not easily escape.

[0100] In this embodiment, the shortest distance L1 is longer than the shortest distance L2. In this way, by separating the welded portion 72, from which heat easily escapes, from the web plate 32, from which heat also easily escapes, the welded portion 72 can be configured not to be concentrated in a position from which heat easily escapes (near the web plate 32). As a result, heat in the first region Z1 is less likely to be transmitted to the web plate 32 than in the past, and the occurrence of the second peeling marks A2 shown in FIG. 15 can be suppressed.

[0101] [Measure D: Make the first weld shorter than the second weld] In addition, the sum of the lengths in the tunnel extension direction of the multiple welds 72 (first welds: welds from which heat escapes easily) formed on the first wall portion 33a is shorter than the sum of the lengths in the tunnel extension direction of the multiple welds 73 (second welds: welds from which heat escapes less easily) formed on the second wall portion 33b.

[0102] 9, for example, welds 72 are provided at four spots over a given length, while welds 73 are provided at five spots over a given length. Therefore, the total length of the multiple welds 72 in the tunnel extension direction is one spot shorter than the total length of the multiple welds 73 in the tunnel extension direction. Note that the number of spots for welds 72 and 73 is an example, and other numbers of spots may also be used.

[0103] Because the total length of the multiple welds 72 is short, it is possible to prevent heat from the first region Z1 from escaping to the reinforcing member 33 via the welds 72. Furthermore, by increasing the total length of the multiple welds 73, it is possible to maintain the bonding strength between the outer frame 31 and the reinforcing member 33.

[0104] [Modification] Modifications of the embodiment will be described below. In the modifications, the same components as those in the above embodiment will be denoted by the same reference numerals and descriptions thereof will be omitted as appropriate.

[0105] [Modification 1 of reinforcing member] FIG. 11 is a diagram showing a reinforcing member according to a modified example. The reinforcing member 33 in the above embodiment has a trapezoidal cross section, and forms a closed space S1 between itself and the outer frame 31. However, the cross-sectional shape of the reinforcing member is not limited to a trapezoidal shape.

[0106] The reinforcing member may be a reinforcing member 34 having a rectangular cross section as shown in Figure 11(a), a reinforcing member 35 having a triangular (V-shaped) cross section as shown in Figure 11(b), or a reinforcing member 36 having an arc-shaped (U-shaped) cross section as shown in Figure 11(c). In any of these reinforcing members 34 to 36, a closed space S1 is formed between the outer frame 31 and the reinforcing member 33, making it difficult for heat from the lining concrete C1 to escape into the tunnel interior, and thus suppressing the occurrence of the second peeling marks A2 in Figure 15.

[0107] 11(d), the reinforcing member may be composed of multiple members. The reinforcing member 37 is composed of a first member 37a having a rectangular cross section and a second member 37b having a flat cross section, joined by welding, for example. The first member 37a is fixed to the outer frame 31 so that its rectangular opening faces downward, and the second member 37b is fixed to the outer frame 31 so as to cover the opening of the first member 37a.

[0108] Because a closed space S2 is formed between the first member 37a and the second member 37b, heat transferred from the outer frame 31 to the outer frame 31 side of the reinforcing member 37 is insulated by the air in the closed space S2, and it is possible to prevent the heat from being transferred to the inside of the tunnel of the reinforcing member 37. As a result, it becomes difficult for heat from the lining concrete C1 to escape to the inside of the tunnel, and it is possible to prevent the occurrence of the second peeling marks A2 in Figure 15.

[0109] [Modification 2 of reinforcing member] 12 is a diagram showing a modified metal formwork 300. The metal formwork 300 of this modified example differs from the above embodiment in that it has a reinforcing member 38 instead of the reinforcing member 33 of the formwork 3 according to the above embodiment, but is the same in other respects.

[0110] In the above embodiment, the heat from the lining concrete C1 is more reliably prevented from escaping into the tunnel by a combination of forming the closed space S1 in the reinforcing member 33 and forming the insulating coating 6 on the entire tunnel-side surface of the side portion 3b, including the exposed surface 31a of the outer frame 31. However, the insulation of the formwork 3 may be achieved mainly by the insulating coating 6 without providing the closed space in the reinforcing member.

[0111] The reinforcing member 38 has a rectangular cross section with an opening facing downward, similar to the first member 37a. The opening of the reinforcing member 38 is not blocked, and no closed space is formed in the reinforcing member 38. The heat insulating coating 6 is formed on the entire surface of the inside of the tunnel of the formwork 300, including the exposed surface 31a of the outer frame 31 and the reinforcing member 38. The composition of the heat insulating coating 6 is the same as in the above embodiment.

[0112] Even with this configuration, the heat insulating coating 6 can prevent the heat from the lining concrete C1 from escaping into the tunnel, so the quality of the lining concrete C1 can be further improved.

[0113] [Variation 1 of the thermal insulation coating] FIG. 13 is a diagram showing a metal formwork 301 according to a modified example. The metal formwork 301 of this modified example differs from the above embodiment in that it has a rust-preventing coating 60 instead of the insulating coating 6 on part of the formwork 3 of the above embodiment, but is otherwise the same.

[0114] In the above embodiment, the heat insulating coating 6 is formed on the entire surface of the formwork 3 facing inside the tunnel, including the exposed surface 31a of the outer frame 31 and the reinforcing members 38. However, the heat insulating coating 6 only needs to be formed on at least a part of the exposed surface 31a, and does not have to be formed on the entire surface of the formwork 3 facing inside the tunnel.

[0115] The heat insulating coating 6 is applied, for example, by spraying onto the surface of the formwork 3 on the inside of the tunnel. The particle size of the heat insulating material 62 (for example, wood chips or fly ash) is larger than the particle size of the anti-rust material 61. For this reason, when the heat insulating coating 6 containing the heat insulating material 62 is spray applied, frequent maintenance of the spray nozzle may be required. For this reason, it may be easier to apply the heat insulating coating 6 only in areas where insulation is particularly required, and to form the anti-rust coating 60 using only the anti-rust material 61 without the heat insulating material 62 added in areas where insulation is less required.

[0116] 13, a heat insulating coating 6 is formed in a first region Z1 (a region from which heat can easily escape) of the exposed surface 31a where the heating member 5 is not installed, and a rust preventive coating 60 is formed in a second region Z2 (a region from which heat cannot easily escape) of the exposed surface 31a where the heating member 5 is installed. The rust preventive coating 60 of this modification is a coating that contains a rust preventive material 61 as a base and does not contain a heat insulating material 62 as an additive.

[0117] Furthermore, the third region Z3 where the reinforcing member 33 is located can be said to be a region where heat is less likely to escape because the closed space S1 prevents heat from escaping from the outer frame 31 into the cavity. For this reason, the third region Z3 is also mainly formed with the rust-preventive coating 60 rather than the thermal insulating coating 6. Furthermore, in the portion of the third region Z3 that is circumferentially adjacent to the first region Z1 where heat is less likely to escape, the thermal insulating coating 6 is formed to ensure more reliable insulation. Note that the thermal insulating coating 6 may be formed over the entire third region Z3.

[0118] With this configuration, the heat insulating coating 6 is formed intensively in areas where heat is likely to escape, ensuring the heat insulation of the formwork 301 while reducing the amount of heat insulating material 62 used, thereby reducing the frequency of spray nozzle maintenance and improving workability. Furthermore, reducing the amount of heat insulating material 62 used also reduces the material cost of the heat insulating coating 6.

[0119] Furthermore, by forming the rust-preventive coating 60 instead of the heat-insulating coating 6 in the second region Z2 where heat is input from the heating element 5 to the outer frame 31, the efficiency of heat input from the heating element 5 to the outer frame 31 is improved, making it possible to heat the lining concrete C1 more efficiently. As a result, the quality of the lining concrete C1 can be further improved.

[0120] The rust-preventive coating 60 may be a coating containing the rust-preventive material 61 as a base and the heat-insulating material 62 as an additive at a lower content than the heat-insulating coating 6. For example, if the heat-insulating coating 6 contains the heat-insulating material 62 at a concentration of 50% by volume relative to the rust-preventive material 61, the rust-preventive coating 60 may contain the heat-insulating material 62 at half that concentration, 25% by volume.

[0121] Even in this case, the amount of insulating material 62 used is reduced, which results in improved workability and reduced material costs, and since the rust-preventing coating 60 has lower insulating performance than the insulating coating 6, the efficiency of heat input from the heating member 5 to the outer frame 31 can be improved.

[0122] The content of the insulating material 62 may be varied in stages depending on the ease of heat dissipation. For example, the insulating coating 6 may be formed in the first region Z1, where heat dissipation is greatest, with the maximum amount of insulating material 62 (e.g., 50% by volume) relative to the rust-preventive material 61. The rust-preventive coating 60 may be formed in the second region Z2, where heat dissipation is least likely. The rust-preventive coating 60 may be formed in the third region Z3, where heat dissipation is greater than the second region Z2 but less than the first region Z1, with the rust-preventive coating 60 containing the insulating material 62 at a predetermined level (e.g., 10 to 25% by volume) relative to the rust-preventive material 61, but less than the maximum amount. This configuration allows for the formation of a suitable coating depending on the insulation requirements.

[0123] [Variation 2 of the thermal insulation coating] 5 is formed in one or more layers by applying a paint containing a rust-preventing material 61, a heat-insulating material 62, and a solvent such as thinner once or multiple times. However, the bottom layer (i.e., the layer applied first) may not contain the heat-insulating material 62 and may be formed by applying a paint containing the rust-preventing material 61 and a solvent once or multiple times.

[0124] 5 may be a multi-layer coating film, with the bottom layer being an anti-rust coating film 60 that does not contain the insulating material 62, and the top layer being a coating film that contains the insulating material 62. In this case, since the bottom layer does not contain the insulating material 62, the same rust prevention effect as a conventional anti-rust coating film can be achieved, while the insulating material 62 in the top layer can keep the lining concrete C1 warm.

[0125] 13 may also have a multi-layer structure. In this case, the anti-rust coating film 60 may be formed on the entire surface of the inside of the tunnel of the formwork 301, and the heat insulating coating film 6 may be formed on top of the anti-rust coating film 60 in the first region Z1 where heat is likely to escape.

[0126] [Additional Notes] It should be noted that at least some of the above-described embodiments and various modifications may be combined with each other in any desired manner. Furthermore, the embodiments and modifications disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0127] 1 Slide Center 10 Curing device 2 Gate type cart 2a Base part 2b Post 2c wheels 3 Formwork 3a Top end 3b side 3c Lower end 300 formwork 301 Formwork 31 Outer Frame 31a Exposed surface 31b Covered surface 32 Belly plate 32a through hole 33 Reinforcement member 33a 1st wall section 33b 2nd wall section 33c 3rd wall section 34 Reinforcement member 35 Reinforcement member 36 Reinforcement member 37 Reinforcement member 37a First member 37b Second member 38 Reinforcement member 41 Jack 42 Jack 43 Jack 5 Heating member 51 Heating element 52 Electric wire 6. Heat-insulating coating 60 Rust-preventive coating 61 Rust prevention material 62 Insulation materials 71 Welded section 71a Welded section 71b Welded section 72 Welded section 73 Welded Section 81a Welded section 81b Welded section 81c Welded section 82 Welded parts 83 Welded parts T1 Tunnel C1 Lining concrete R1 rail t1 Inner surface D1 Pouring space S1 Closed space S2 Closed space Y1 steel material X1 Paint film X2 Paint film X3 coating X4 coating X5 coating H1 heat source P1 Sensor P2 Sensor P3 Sensor Tp1 (sensor P1) measured temperature Tp3 (sensor P3) measured temperature Z1 1st area Z2 2nd area Z3 3rd area L1 Shortest distance L L2 Shortest distance L AR1 Arrow AR2 Arrow A1 First peeling mark A2 2nd peeling mark A3 3rd peeling mark

Claims

1. A metal formwork that forms a space for pouring lining concrete between the inner surface of the tunnel and the metal formwork, A heat insulating coating film is formed on the exposed surface of the metal formwork inside the tunnel, The thermal barrier coating includes a rust-preventing material as a base and a thermal barrier material as an additive, The insulating material comprises wood chips or fly ash. Metal formwork.

2. The metal form of claim 1 , wherein the insulating material comprises fly ash.

3. The heat insulating coating contains fly ash at a concentration of 40% by volume or more and 50% by volume or less relative to the rust preventing material. The metal formwork according to claim 2.

4. The metal formwork according to any one of claims 1 to 3 has a length of 2.1 m in the tunnel extension direction, A mobile center with a total length of 10.5 m is constructed by connecting five of the above metal formworks in the direction of the tunnel extension.

Images