Metal formwork and mobile centre

Abstract

To further improve quality of lining concrete.SOLUTION: Provided is a metal form forming a placement space of lining concrete between an inner circumferential surface of a tunnel and itself. The metal form includes: an outer frame 31 facing the inner circumferential surface of the tunnel; web plates extending from both ends of an outer frame in a tunnel extension direction to the inside of the tunnel; reinforcement members 33 arranged at an interval in a circumferential direction on the inside of the tunnel of the outer frame, extending in the tunnel extension direction, and connected to the web plate on one end side and the web plate on the other end side; a plurality of heating members 5 installed intermittently with respect to an exposed surface on the inside of the tunnel of the outer frames arranged in the circumferential direction having the reinforcement members therebetween, to heat lining concrete via the outer frame; a heat insulation coat 6 formed in a first region Z1 in the exposed surface where the heating members are not installed and including a heat insulation material 62 as an additive; and a rust proof coat 60 formed in a second region Z2 in the exposed surface where the heating members are installed, including a rust proof material 61 as a base agent, and containing no heat insulation material 62 as an additive or having low percentage content of the heat insulation material than that of the heat insulation coat.SELECTED DRAWING: Figure 13

Description

[Technical field]

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

[0002] The tunnel lining concrete is poured in predetermined sections using metal forms installed on a slide center that can move in the tunnel extension direction. In order to prevent the poured lining concrete from cracking when it is removed from the form, it is necessary to increase the compressive strength of the lining concrete.

[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] JP 2011-190594 A 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. Fig. 15 is a schematic diagram showing an example of the inner peripheral surface of the lining concrete where peeling has occurred. The peeling shown in Fig. 15 may occur even when the lining concrete is heated. In order to improve the quality of the lining concrete, measures to prevent the peeling of the lining concrete are desired.

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

[0007] (1) The present invention is a metal formwork that forms a pouring space for lining concrete between itself and the inner circumferential surface of a tunnel, the metal formwork comprising: an outer frame that faces the inner circumferential surface of the tunnel; web plates extending 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; a plurality of heating members that are arranged circumferentially with the reinforcing members between them and are intermittently installed on the exposed surface on the inside of the tunnel of the outer frame and heat the lining concrete through the outer frame; a thermal insulation coating film that is formed in a first region of the exposed surface where the heating members are not installed and contains a thermal insulation material as an additive; and a rust prevention coating film that is formed in a second region of the exposed surface where the heating members are installed and contains a rust prevention material as a base and does not contain a thermal insulation material as an additive or has a lower thermal insulation material content than the thermal insulation coating film.

[0008] According to the present invention, 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 to the inside of the tunnel, and the quality of the lining concrete can be improved. In addition, by concentrating the formation of the heat insulating coating on the area where heat is likely to escape, it is possible to reduce the amount of insulating material used while ensuring the thermal insulation of the metal formwork. This improves workability and reduces the material costs for construction.

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

[0010] Both wood chips and fly ash are by-products, and if not utilized, they are disposed of as industrial waste. According to the present invention, wood chips and fly ash can be utilized as recycled resources for a new purpose (insulation material), and therefore the insulation performance of metal forms can be improved while reducing the environmental load.

[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-preventive material.

[0012] If fly ash is added to the rust-preventive material at a concentration exceeding 50% by volume, it may cause problems with 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 the thermal insulation material within the range in which the post-application state, such as adhesion stability, is good. According to the present invention, since 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, it is possible to obtain higher thermal insulation performance while maintaining adhesion stability.

[0013] (4) 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 portions of the reinforcing member that contact both the outer frame and the web plate.

[0014] With this structure, the heat of the outer frame is less likely to be transferred to the web plate than in the past, and the peeling of the lining concrete can be suppressed, which results in an improved quality of the lining concrete.

[0015] (5) A first circumferential end of the reinforcing member facing the first region has a plurality of first welds welded to the outer frame, and a second circumferential end of the reinforcing member facing the second region has a plurality of second welds welded to the outer frame, and a shortest distance between the plurality of first welds and the web plate may be longer than a shortest distance between the plurality of second welds and the web plate.

[0016] According to the present invention, by separating the first welded portion, from which heat easily escapes, from the web plate, from which heat also 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, peeling of the lining concrete can be suppressed, and the quality of the lining concrete can be further improved.

[0017] (6) The second welded portions may be formed at positions that do not overlap with the first welded portions in the circumferential direction.

[0018] This structure allows the locations of the metal formwork that are prone to cooling (welding locations) to be dispersed, which in turn prevents the lining concrete from peeling off and improves the quality of the lining concrete.

[0019] (7) A sum of lengths of the first welded parts in the tunnel extension direction may be shorter than a sum of lengths of the second welded parts in the tunnel extension direction.

[0020] 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 easily escapes. Also, by increasing the total length of the second welded portion through which heat is less likely to escape, it is possible to maintain the joint strength between the outer frame and the reinforcing member.

[0021] (8) 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, a web plate extending from both ends of the outer frame in the tunnel extension direction toward the inside of the tunnel, and 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, wherein the reinforcing members have a plurality of welds welded to the outer frame or the web plate, and no welds are formed in the portions of the reinforcing members that contact both the outer frame and the web plate.

[0022] According to the present invention, the heat of the outer frame is less likely to be transmitted to the web plate than in the past, and the peeling of the lining concrete can be suppressed. As a result, the quality of the lining concrete can be further improved.

[0023] (9) The mobile centre of the present invention is a mobile centre with a total length of 10.5 m, constructed by connecting five of the metal formworks described in (1) to (8) in the tunnel extension direction, the length of which is 2.1 m in the tunnel extension direction.

[0024] By using a 5-span, 2.1m movable center, the number of web plates is reduced compared to the conventional 7-span, 1.5m movable center, which reduces the amount of heat escaping 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 improves the quality of the lining concrete. Effect of the Invention

[0025] According to the present invention, the quality of the lining concrete can be further improved. [Brief description of the drawings]

[0026] [Figure 1] 1 is a diagram showing the overall configuration of a lining concrete construction system according to an embodiment. FIG. [Diagram 2] FIG. 2 is a front view of the slide center according to the embodiment. [Diagram 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. [Diagram 5] 5 is a cross-sectional view of the side of the metal formwork taken along line V in FIG. 4. [Figure 6] FIG. 2 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]13 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, viewed from the inside of the tunnel. [Figure 10] This is a side view of a portion of the side of a metal formwork for a comparative example, viewed from the inside of the tunnel. [Figure 11] 13A and 13B are diagrams showing a reinforcing member according to a modified example. [Figure 12] 13A and 13B are diagrams showing a reinforcing member according to a modified example. [Figure 13] FIG. 13 is a diagram showing a metal formwork according to a modified example. [Figure 14] FIG. 13 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 surface of a lining concrete where peeling has occurred. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] [Causes and solutions to peeling] The present inventors have been conducting extensive research into measures to prevent the peeling of the lining concrete, as exemplified in Fig. 15. In the course of this research, it was discovered that the peeling is particularly likely to occur during construction in winter.

[0028] The inventor also discovered that there are three types of peeling marks, a first peeling mark A1 extending circumferentially as shown in Figure 15, a second peeling mark A2 extending in the tunnel extension direction from the first peeling mark A1 as a starting point, and a third peeling mark A3 located in spots on an imaginary extension line of the second peeling mark A2, and that the positions at which these are formed correspond to the positions of the web panel, the reinforcing members, and the positions where the reinforcing members and the outer frame are welded, respectively, among the components of the formwork.

[0029] From this, the inventors have concluded that the cause of the peeling of the lining concrete when the form is removed is that the heat of the lining concrete is locally cooled by the formwork, and the lining concrete is not heated sufficiently. For this reason, the inventors propose an invention in this application to improve the thermal insulation performance of the formwork. According to this invention, the peeling of the lining concrete when the form is removed can be suppressed, and the quality of the lining concrete can be further improved.

[0030] 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 on the inside of the tunnel. (4) The welds of the reinforcing members are arranged so that they are not concentrated in locations where heat can easily escape.

[0031] 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.

[0032] [Overall system configuration] Fig. 1 is a diagram showing the overall configuration of a construction system for lining concrete 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 primarily lined tunnel T1. 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.

[0033] The slide center 1 and the curing device 10 can travel on rails R1 laid on the floor surface inside the tunnel T1. The slide center 1 pours the lining concrete C1 in a predetermined span from the tunnel entrance side toward the face side (in the direction of the arrow in Fig. 1). The curing device 10 cures the poured lining concrete C1 in a predetermined span.

[0034] [Slide center configuration] 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 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.

[0035] The slide center 1 is equipped with a gate-shaped cart 2 capable of running within the tunnel T1, and a number of metal formwork 3 (hereinafter simply referred to as "formwork 3") which serve as dams for molding the inner surface of the lining concrete C1.

[0036] The gate-type cart 2 includes a base 2a and a number 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 gate-type cart 2 travels inside the tunnel T1 by rolling along the rails R1.

[0037] The formwork 3 has a cross-sectional arc shape that is approximately along the inner circumferential surface t1 of the tunnel T1, and forms a pouring space D1 for pouring the lining concrete C1 between the formwork 3 and the inner circumferential surface t1 of the tunnel T1. The formwork 3 is also called a center form. As shown in FIG. 2, the formwork 3 has a top end 3a that covers the top end (crown) of the inner circumferential surface t1, side parts 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 bottom end of the side part 3b and covers the lower part of the side wall of the inner circumferential surface t1.

[0038] 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 gate-type cart 2. The side portion 3b and the bottom end 3c are each supported so as to be rotatable in the width direction by a plurality of jacks 42, 43 provided on the outer surfaces of the supports 2b. The top end 3a, the side portion 3b and the bottom end 3c each have a pouring port (not shown) for pouring ready-mixed concrete into the pouring space D1.

[0039] Please refer to Fig. 3. In this embodiment, a slide centre 1 with a standard length of 10.5 m is constructed by connecting a plurality of formwork 3 in the tunnel extension direction. Here, in a conventional slide centre (for example, Fig. 3 of JP 2011-190594 A), when a standard length of 10.5 m is adopted, a "7 span 1.5 m" formwork is used in which the formwork is divided into 7 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.

[0040] 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. That is, the slide center 1 of this embodiment has "5 spans of 2.1 m", which is two spans less than the conventional type. With this configuration, the number of web plates 32 described below is less than the conventional type, so that the amount of heat escaping from the heated lining concrete C1 through the web plates 32 can be reduced.

[0041] As a result, peeling of the lining concrete during removal from the form is suppressed in accordance with the reduction in the number of web plates 32, and the number of first peeling marks A1 in Fig. 15 is reduced. This makes it possible to further improve the quality of the lining concrete C1.

[0042] In addition, 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.

[0043] FIG. 14 is a schematic diagram showing the divided formwork loaded onto a truck. 14(a) and (b) are a plan view and a side view showing a part of a formwork 3 with a span length of 2.1 m (two side parts 3b are shown in the figure) loaded on the loading platform B1 of a truck Tr1. The part of the formwork 3 is secured to the truck Tr1 in an upright position, for example, with the tunnel extension direction facing vertically. The same is true for a conventional span length of 1.5 m.

[0044] The truck Tr1 is, for example, a 10-ton truck, and the height of the loading platform B1 is about 1.5 m from the ground. In principle, the loading height of a truck is regulated to 3.8 m or less, and if the span length is 2.1 m, it falls within the regulated height, so the divided formwork 3 can be transported from the factory to the tunnel T1 using the truck Tr1.

[0045] 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 possibly causing problems in transporting the formwork 3. For this reason, five spans is particularly suitable as the number of spans, as this is the maximum span length within the range that allows transport by truck. If the problem of transportation can be solved, the number of spans may be four or less, or six, in the practice of the present invention.

[0046] Furthermore, by configuring the slide center 1 to have two spans less than the conventional type, the number of parts of the slide center 1 is less than before, which reduces the manufacturing cost of the slide center 1 and shortens the time required for assembly and disassembly of 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, 6 days for assembly, and 4 days for disassembly, but in the case of a slide center 1 with 5 spans and 2.1 m, for example, the number of trucks required for transportation can be reduced to 7, and the assembly work can be completed in 5 days and the disassembly work can be completed in 3 days.

[0047] [Formwork configuration] 4 is a perspective view of a portion of the side portion 3b of the formwork 3, seen obliquely from above. Below, the side portion 3b of the formwork 3 will be representatively described, 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).

[0048] The outer frame 31 is a metal (eg, steel) plate material extending 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.

[0049] The web plates 32 are metal (for example, steel) plates extending toward the inside of the tunnel from both ends in the tunnel extension direction of the outer frame 31. The web plates 32 have the function of supporting the outer frame 31 and are also called webs.

[0050] The reinforcing member 33 is a metal (e.g., steel) member that reinforces the tunnel inner side of the outer frame 31, and is also called a stiffening material. The reinforcing member 33 is provided on the tunnel inner side of the outer frame 31, extends in the tunnel extension direction, and is connected to the web plate 32 on one end side and the web plate 32 on the other end side. A plurality of reinforcing members 33 are lined up at intervals in the circumferential direction on the tunnel inner side of the outer frame 31.

[0051] Fig. 5 is a cross-sectional view of the side portion 3b of the formwork 3 cut along the cutting line V in Fig. 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 to the inside of the tunnel, a second wall portion 33b adjacent to the first wall portion 33a in the circumferential direction and extending from the outer frame 31 to 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 therebetween.

[0052] The surface of the outer frame 31 on the inside of the tunnel includes an exposed surface 31a 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 therebetween. 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 therebetween.

[0053] As shown by the second peeling marks A2 in Fig. 15, heat from the lining concrete C1 tends to escape from the portion where the outer frame and the reinforcing member are connected to the inside of the tunnel. In this embodiment, by making the cross-sectional shape of the reinforcing member 33 a hollow structure, it is possible to reduce the contact area between the outer frame 31 and the reinforcing member 33 compared to the case where a reinforcing member with a solid structure is used. This makes it possible to prevent heat from the lining concrete C1 from escaping to the inside of the tunnel through the outer frame 31 and the reinforcing member 33.

[0054] In addition, because a closed space S1 is formed between the outer frame 31 and the reinforcing member 33, the heat of the covering surface 31b of the outer frame 31 is insulated by the air in the closed space S1, and the heat transfer to the reinforcing member 33 can be further suppressed. As a result, the heat of the lining concrete C1 is less likely to escape to the inside of the tunnel, and the occurrence of the second peeling marks A2 in Fig. 15 can be suppressed. This can further improve the quality of the lining concrete C1.

[0055] [About heating components] Please refer to 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 intermittently installed on the plurality of exposed surfaces 31a. In this embodiment, the heating members 5 are installed on every other exposed surface 31a. Note that it is sufficient that the heating members 5 are installed intermittently on at least some of the exposed surfaces 31a, and they may be installed continuously on the plurality of exposed surfaces 31a adjacent in the circumferential direction.

[0056] 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 causing the lining concrete C1 to obtain a predetermined compressive strength.

[0057] The heating member 5 may have a pipe through which a heat medium in the form of 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 is pumped to the pipe by a pump.

[0058] By installing the heating members 5 intermittently, the number of heating members 5 can be reduced. This allows the cost of materials and the energy cost for operating the heating members 5 to be reduced. On the other hand, when the heating members 5 are installed intermittently, heat from the lining concrete C1 is more likely to escape to the inside of the tunnel from the exposed surface 31a where the heating members 5 are not installed. For this reason, in this embodiment, a heat insulating coating 6, which will be described later, is provided on the exposed surface 31a to allow more heat to remain in the lining concrete C1.

[0059] [About the heat insulating coating] Please refer to Fig. 5. The side portion 3b of the formwork 3 is further provided with a heat insulating coating 6. The heat insulating coating 6 is formed on the entire surface of the side portion 3b on the inside of the tunnel, including the exposed surface 31a of the outer frame 31. The heat insulating coating 6 contains a rust prevention material 61 as a base and a heat insulating material 62 as an additive.

[0060] The rust-preventive material 61 is a known rust-preventive paint, for example, "Quick-drying Rust-preventive Eco" manufactured by Nippon Paint Co., Ltd.

[0061] The heat insulating material 62 includes, for example, wood chips or fly ash. However, the heat insulating material 62 is not limited to these and may include other heat insulating materials. As the heat insulating material, for example, a material having a particle size of several tens of μm to several hundreds of μm and a hollow structure or a porous structure is preferable. As the other heat insulating material, for example, hollow glass beads may be included.

[0062] When fly ash is used as the heat insulating material 62, the heat insulating coating 6 contains, for example, fly ash at a concentration of 40 volume % or more and 50 volume % or less. In other words, the heat insulating material 62 is added so that the volume of the heat insulating material 62 is about 70 to 90 per 100 volume of the rust preventive material 61.

[0063] If fly ash is added to the rust-preventive material 61 at a concentration exceeding 50% by volume, this may impair the adhesion stability of the heat insulating coating 6 (for example, the heat insulating coating 6 may become easily peeled off). On the other hand, in order to improve the heat insulating performance, it is preferable to add the maximum amount of fly ash as the heat insulating material 62 within a range in which the post-application state, such as adhesion stability, is good, and in this embodiment, a concentration of around 50% by volume is more preferable. However, if the post-application state is good, fly ash may be added to the rust-preventive material 61 at a concentration exceeding 50% by volume.

[0064] Wood chips are, for example, powdered "sawdust" or "sawdust" that are generated when cutting wood. The grain size of wood chips is, for example, about 200 μm. Wood chips have traditionally been used as a cushioning material for transported goods and as bedding for livestock, but the present inventors have focused on the heat insulating properties of wood and have come up with a new idea of ​​adding wood chips as a heat insulating material 62 to a rust prevention material 61.

[0065] 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, about 10 μm to 100 μm. Fly ash has 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 heat insulating properties, and have come up with a new idea of ​​adding fly ash to a rust prevention material 61 as a heat insulating material 62.

[0066] Both wood chips and fly ash are by-products, and if not utilized, they are disposed of as industrial waste. According to the heat insulating coating film 6 of this embodiment, wood chips and fly ash can be utilized as recycled resources for new applications (thermal insulation materials), and the thermal insulation performance of the formwork 3 can be improved while reducing the environmental load. As a result, heat from the lining concrete C1 is less likely to escape to the inside of the tunnel through the formwork 3, and the quality of the lining concrete C1 can be further improved.

[0067] [An experimental example of heat insulating coating] In order to confirm the effect of using wood chips or fly ash as the thermal insulation material 62 of the thermal barrier coating 6, the inventors conducted the experiment described below.

[0068] Figure 6 is a schematic diagram showing an experimental example of a heat insulating coating. Five types of coating films X1 to X5 were applied to one side of a 6 mm thick steel material Y1, and five samples were prepared by attaching a heat source H1 (resistance heater) to the other side of the steel material Y1. Three sensors P1 to P3 for detecting temperature were installed on the coating films X1 to X5. Sensor P1 was installed directly behind the heat source H1, sensor P2 was installed at a position 7 cm away from the center of sensor P1, and sensor P3 was installed at a position 10 cm away from the center of sensor P2.

[0069] The temperature of the heat source H1 was set to 60°C, and the heat transferred from the heat source H1 to the sensors P1-P3 via the steel Y1 and the coatings X1-X5 was measured. This allows the heat escaping from the heated lining concrete C1 (simulated by the heat source H1) to the inside of the tunnel via the outer frame 31 (simulated by the steel Y1) and the heat insulating coating 6 (simulated by the coatings X1-X5) to be evaluated by the temperatures measured by the sensors P1-P3.

[0070] FIG. 7 is a table showing the coatings used in the experiment. Coating film X1 is a simple rust-preventive coating film that contains a rust-preventive material as a base material and does not contain a heat-insulating material as an additive, and is a reference example for this experiment. The rust-preventive material used was "Quick-drying Rust Prevention Eco" manufactured by Nippon Paint Co., Ltd. The same rust-preventive material as coating film X1 was used as the base material for coating films X2 to X4.

[0071] 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).

[0072] Coating X3 contains a rust-preventive material as a base and fly ash as an additive. The fly ash was added so that the volume of the rust-preventive material was about 80 parts by volume per 100 parts by volume (about 44% by volume).

[0073] Coating X4 contains a rust-preventive material as a base material, and "Heat Cut Powder" manufactured by Toa System Create Co., Ltd. as an additive. Heat Cut Powder was added so that the volume of the heat cut powder was about 80 parts per 100 parts by volume of rust-preventive material (about 44% by volume concentration). Heat Cut Powder is a ceramic powder, and is an additive that has traditionally been used for heat insulation purposes, so it was prepared as a comparative example.

[0074] Coating X5 is "Thermal Insulation Coat" manufactured by Toho Paint Co., Ltd. The thermal insulation coat is a thermal insulation paint in which thermal insulation pigments and the like are added to acrylic silicone resin, and was prepared as a comparative example.

[0075] Coatings X1 to X4 were each formed by one spray application, while coating X5 was spray applied three times with an interval between each application, according to the specifications.

[0076] The thicknesses of coating films X1 to X5 were measured using a paint thickness gauge. The thickness of coating film X1 was 100 μm, and the thicknesses of coating films X2, X3, and X4 were 412 μm, 373 μm, and 508 μm, respectively. Coating films X2, X3, and X4 were thicker than coating film X1 because granular additives of several tens to several hundreds of μm were added to the rust prevention material. Coating film X5 had a thickness of 983 μm, the thickest due to repeated coating.

[0077] Fig. 8 is a graph showing the results of the experiment. The horizontal axis of the graph indicates the time [min] elapsed since the start of heating of the heat source H1, and the vertical axis of the graph indicates the temperature [°C]. The lines at the top of the graph are the temperatures measured by sensor P1, the lines in the middle of the graph are the temperatures measured by sensor P2, and the lines at the bottom of the graph are 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.

[0078] Here, attention is focused on the temperature difference (Tp1-Tp3) between the temperature Tp1 measured by sensor P1 and the temperature Tp3 measured by sensor P3 at a certain elapsed time. The temperature difference is represented on the graph by, for example, an arrow AR1. The larger this temperature difference is, the less heat is transferred to sensor P3, meaning that the heat insulating performance of the coating is high. The temperature difference at an elapsed time of 25 minutes is shown in the right column of the table in FIG. 7.

[0079] As shown in FIG. 7, the temperature difference was 17.8°C for the reference coating X1 (rust-preventive coating), 20.6°C for the coating X2 (wood chips), and 22.3°C for the coating X3 (fly ash). In both the wood chips and the fly ash, higher insulation performance was obtained than in the reference examples.

[0080] In addition, the temperature difference between the coating films X2 and X3 was higher than 16.0°C for the comparative coating film X4 (heat cut powder) and 17.8°C for the coating film X5, and it was confirmed that the coating films X2 and X3 have higher insulation performance than the coating films X4 and X5, which have traditionally been used as insulation materials. As described above, the heat insulating coating 6, which is based on the rust-preventive material 61 and to which wood chips or fly ash is added as the heat insulating material 62, has favorable heat insulating properties.

[0081] [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 the inside of the tunnel. FIG. 10 is a schematic diagram for explaining a comparative example of the welding position. Hereinafter, the welding position of the reinforcing member 33 will be described with reference to FIGS.

[0082] First, a comparative example of the welding position 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, 81c (also simply referred to as "welds 81"), and is tap-welded to outer frame 31 by a plurality of welds 82, 83.

[0083] More specifically, the welded portion 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 manner, the reinforcing member 33 can be fixed to both the outer frame 31 and the web plate 32, so a welded portion is usually formed in this position.

[0084] 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. Moreover, 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.

[0085] 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 Fig. 10(b), the welds 82 and the welds 83 overlap in the circumferential direction.

[0086] Since the reinforcing member 33 and the outer frame 31 and the web plate 32 are integrated at the welded parts 81-83, heat from the outer frame 31 and the web plate 32 is easily transferred from the welded parts 81-83 to the reinforcing member 33. That is, the formwork 3 is particularly susceptible to cooling at the welded parts 81-83, which causes the second peeling marks A2 and third peeling marks A3 in Fig. 15 to be formed.

[0087] Therefore, in this embodiment, the positions at which the welds of the reinforcing member 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.

[0088] 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, in the present invention, it is sufficient to implement at least one of measures A to D, and it is not essential to include all of them.

[0089] [Measure A: Move the weld away from the point where the reinforcing member, web plate, and outer frame come into contact] Please refer to the enlarged view of FIG. 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 the corner where the first wall portion 33a and the third wall portion 33c are connected and in the vicinity thereof, and the welds 71b are formed at the corner where the second wall portion 33b and the third wall portion 33c are connected and in the vicinity thereof. The welds 71a, 71b are located away from the outer frame 31. In other words, the welds 71 ​​are not formed in the portion of the reinforcing member 33 that contacts both the outer frame 31 and the web plate 32.

[0090] Since the web plate 32 is a steel material that extends toward the inside of the tunnel, it functions like a heat dissipation fin in the formwork 3, and tends to release heat from the lining concrete C1 toward the inside of the tunnel. In the conventional welding method, welding is performed on the parts of the reinforcing member 33 that contact both the outer frame 31 and the web plate 32 as shown in Figure 10, so that heat from the outer frame 31 is likely to be transferred to the web plate 32 via the welded parts 81a, 81b, which is thought to be one of the causes of the second peeling mark A2 in Figure 15.

[0091] 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. Therefore, the heat of the outer frame 31 is less likely to be transmitted to the web plate 32 than in the past, and the occurrence of the second peeling marks A2 can be suppressed. This can further improve the quality of the lining concrete C1.

[0092] [Measure B: Arrange the welds in a staggered pattern] Refer to 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 at 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).

[0093] In the example of Fig. 10, the welded parts 82, 83 which cool easily overlap in the circumferential direction, so that the positions of the formwork 3 which cool easily are concentrated when viewed in the tunnel extension direction as indicated by the arrow AR2 in Fig. 10. It is considered that such a concentration of the welded positions is one of the causes of the third peeling mark A3 in Fig. 15.

[0094] In contrast, in this embodiment, the welded parts 72, 73 are arranged in a staggered pattern, so that the positions (welded positions) of the formwork 3 that are prone to cooling 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.

[0095] [Measure C: Place the second welded part farther away from the web plate than the first welded part] As described above, the heating members 5 of this embodiment are intermittently installed 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.

[0096] Because no heating member 5 is installed in the first region Z1, the first region Z1 becomes colder than 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 member 5 is installed in the second region Z2, the second region Z2 becomes hotter than 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.

[0097] 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 and the reinforcing member 33, and therefore can be considered to be a weld (first weld) from which heat easily escapes. 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 and the reinforcing member 33, and therefore can be considered to be a weld (second weld) from which heat does not easily escape.

[0098] 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 concentrate in a position from which heat easily escapes (near the web plate 32). As a result, the 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.

[0099] [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.

[0100] 9, for example, welds 72 are provided at four spots over a given length, whereas 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 shorter by one spot than the total length of the multiple welds 73 in the tunnel extension direction. Note that the number of spots of welds 72, 73 is merely an example, and other numbers of spots may be used.

[0101] Since 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 making the total length of the multiple welds 73 longer, the bonding strength between the outer frame 31 and the reinforcing member 33 can be maintained.

[0102] [Modifications] 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 the description thereof will be omitted as appropriate.

[0103] [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.

[0104] The reinforcing member may be a reinforcing member 34 having a rectangular cross section as shown in Fig. 11(a), a reinforcing member 35 having a triangular (V-shaped) cross section as shown in Fig. 11(b), or a reinforcing member 36 having an arc-shaped (U-shaped) cross section as shown in Fig. 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, so that heat from the lining concrete C1 is less likely to escape to the inside of the tunnel, and the occurrence of the second peeling mark A2 in Fig. 15 can be suppressed.

[0105] The reinforcing member may be composed of multiple members, such as reinforcing member 37 shown in Fig. 11(d). 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, which are joined by welding, for example. First member 37a is fixed to outer frame 31 so that a rectangular opening faces downward, and second member 37b is fixed to outer frame 31 so as to close the opening of first member 37a.

[0106] Since 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 suppress the transfer of heat 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 suppress the occurrence of the second peeling mark A2 in Fig. 15.

[0107] [Modification 2 of reinforcing member] 12 is a diagram showing a modified metal formwork 300. The modified metal formwork 300 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.

[0108] In the above embodiment, the heat of the lining concrete C1 is more reliably prevented from escaping to the inside of the tunnel by a combination of forming the closed space S1 in the reinforcing member 33 and forming the heat insulating coating 6 on the entire inside of the tunnel of the side portion 3b including the exposed surface 31a of the outer frame 31. However, the heat insulation of the formwork 3 may be realized mainly by the heat insulating coating 6 without providing a closed space in the reinforcing member.

[0109] 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 exposed surface 31a of the outer frame 31 and the entire surface of the inside of the tunnel of the formwork 300 including the reinforcing member 38. The composition of the heat insulating coating 6 is the same as in the above embodiment.

[0110] Even with this configuration, the heat insulating coating 6 can prevent heat from the lining concrete C1 from escaping into the tunnel, so the quality of the lining concrete C1 can be further improved.

[0111] [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-preventive coating film 60 instead of the insulating coating film 6 on a portion of the formwork 3 of the above embodiment, but is otherwise in common.

[0112] In the above embodiment, the heat insulating coating 6 is formed on the entire surface of the formwork 3 facing the inside of the tunnel, including the exposed surface 31a of the outer frame 31 and the reinforcing member 38. However, it is sufficient that the heat insulating coating 6 is formed on at least a part of the exposed surface 31a, and it is not necessary that the heat insulating coating 6 is formed on the entire surface of the formwork 3 facing the inside of the tunnel.

[0113] 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 rust prevention material 61. For this reason, when the heat insulating coating 6 containing the heat insulating material 62 is sprayed, 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 the areas where insulation is particularly required, and to form the rust prevention coating 60 using a simple rust prevention material 61 without the heat insulating material 62 added in the areas where insulation is less required.

[0114] 13, the heat insulating coating 6 is formed in a first region Z1 (region from which heat escapes easily) of the exposed surface 31a where the heating member 5 is not installed, and the rust-preventive coating 60 is formed in a second region Z2 (region from which heat escapes less easily) 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.

[0115] Moreover, the third region Z3 where the reinforcing member 33 is located can be said to be a region from which heat does not easily 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 insulation coating 6. In addition, the thermal insulation coating 6 is formed in the portion of the third region Z3 adjacent in the circumferential direction to the first region Z1 from which heat does not easily escape, in order to provide more reliable insulation. Note that the thermal insulation coating 6 may be formed over the entire third region Z3.

[0116] With this configuration, the heat insulating coating 6 is concentrated in areas where heat is likely to escape, ensuring the heat insulating properties of the formwork 301 while reducing the amount of heat insulating material 62 used, thereby reducing the frequency of maintenance of the spray nozzle and improving workability. Also, reducing the amount of heat insulating material 62 used can reduce the material cost of the heat insulating coating 6.

[0117] Furthermore, by forming the rust-preventive coating film 60 instead of the heat-insulating coating film 6 in the second region Z2 where heat is input from the heating member 5 to the outer frame 31, the efficiency of heat input from the heating member 5 to the outer frame 31 is improved, so that the lining concrete C1 can be heated more efficiently. As a result, the quality of the lining concrete C1 can be further improved.

[0118] The rust-preventive coating film 60 may be a coating film containing the rust-preventive material 61 as a base and containing the heat-insulating material 62 as an additive at a lower content than the heat-insulating coating film 6. For example, if the heat-insulating coating film 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 film 60 may contain the heat-insulating material 62 at a concentration of 25% by volume, half of that.

[0119] 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-preventive 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.

[0120] The content of the heat insulating material 62 may be changed stepwise depending on the ease of heat escape. For example, the heat insulating coating film 6 may be formed in the first region Z1 where heat escapes most easily, with the heat insulating material 62 being contained to the maximum extent (for example, 50% by volume) relative to the rust preventing material 61, the heat insulating coating film 60 may be formed in the second region Z2 where heat escapes least easily, and the heat insulating coating film 60 may be formed in the third region Z3 where heat escapes more easily than the second region and less easily than the first region Z1, with the heat insulating material 62 being contained to a predetermined extent less than the maximum extent (for example, 10 to 25% by volume) relative to the rust preventing material 61. By configuring in this way, a suitable coating film can be formed depending on the need for insulation.

[0121] [Variation 2 of the thermal insulation coating] 5 is formed in one or more layers by applying paint containing a rust-preventive 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 paint containing the rust-preventive material 61 and a solvent once or multiple times.

[0122] That is, the thermal insulation coating 6 in Fig. 5 may be a multi-layer coating, with the bottom layer being made of antirust coating 60 that does not contain thermal insulation material 62, and the top layer being a coating that contains thermal insulation material 62. In this case, since the bottom layer does not contain thermal insulation material 62, it is possible to achieve the same rust prevention effect as a conventional antirust coating, while keeping the lining concrete C1 warm with the thermal insulation material 62 in the top layer.

[0123] The heat insulating coating film 6 in Fig. 13 may also have a multi-layer structure. In this case, the rust-preventive 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 the upper layer of the rust-preventive coating film 60 in the first region Z1 where heat is likely to escape.

[0124] [Additional Note] In addition, at least a part of the above-mentioned embodiment and various modified examples may be arbitrarily combined with each other. In addition, the embodiment and modified examples disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0125] 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 members 33a 1st wall section 33b 2nd wall part 33c 3rd wall section 34 Reinforcement members 35 Reinforcement members 36 Reinforcement members 37 Reinforcement members 37a First member 37b Second member 38 Reinforcement members 41 Jack 42 Jack 43 Jack 5 Heating material 51 Heating element 52 Electric wire 6. Thermal insulation coating 60 Anti-rust coating 61 Rust prevention material 62 Insulation materials 71 Welding 71a Welding 71b Welding 72 Welding 73 Welding 81a Welding 81b Welding 81c Welding 82 Welding 83 Welding T1 Tunnels 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 circumferential surface of a tunnel, An outer frame facing the inner circumferential surface of the tunnel; A web plate extending from both ends of the outer frame in the tunnel extension direction toward the inside of the tunnel; Reinforcing members arranged at intervals in the circumferential direction on the tunnel inner side of the outer frame, extending in the tunnel extension direction and connected to the web plate on one end side and the web plate on the other end side; A plurality of heating members are intermittently installed on the exposed surface of the outer frame on the inside of the tunnel, arranged in a circumferential direction with the reinforcing member sandwiched therebetween, and heat the lining concrete through the outer frame; A heat insulating coating film is formed in a first region of the exposed surface where the heating member is not installed, and contains a heat insulating material as an additive; A rust-preventive coating film is formed in a second region of the exposed surface where the heating member is installed, and contains a rust-preventive material as a base and does not contain a heat-insulating material as an additive or has a lower content of heat-insulating material than the heat-insulating coating film; A metal formwork comprising:

2. 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; The metal formwork according to claim 1.

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-preventive material. The metal formwork according to claim 2.

4. The reinforcing member has a plurality of welded portions welded to the outer frame or the web plate, The welded portion is not formed in a portion of the reinforcing member that is in contact with both the outer frame and the web plate. A metal formwork according to any one of claims 1 to 3.

5. a first circumferential end portion of the reinforcing member facing the first region has a plurality of first welds welded to the outer frame; a second circumferential end portion of the reinforcing member facing the second region has a plurality of second welded portions welded to the outer frame; A shortest distance between the plurality of first welded portions and the web plate is longer than a shortest distance between the plurality of second welded portions and the web plate. A metal formwork according to any one of claims 1 to 4.

6. The second welded portions are formed at positions that do not overlap with the first welded portions in the circumferential direction. The metal formwork according to claim 5.

7. A sum of lengths of the first welded portions in the tunnel extension direction is shorter than a sum of lengths of the second welded portions in the tunnel extension direction. The metal formwork according to claim 5 or 6.

8. The length of the metal formwork according to any one of claims 1 to 7 in the tunnel extension direction is 2.1 m, The five metal formworks are connected in the direction of the tunnel extension to create a mobile centre with a total length of 10.5 m.

Images