JP2007297906A - Composite segment structure formed of steel and concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite segment structure capable of taking a measure against a fire at low cost in an extremely short construction period. <P>SOLUTION: This composite segment structure comprises a steel shell segment body frame 31 in which steel shell side-frames 44 formed of steel outer flanges 41 and steel inner flanges 43 joined to each other through a web 41 are disposed in parallel with each other at a predetermined interval in the axial direction of a tunnel and the steel shell outer flanges 42 are connected to each other through a skin plate 45, and fire resistant concrete 32 placed in the inner space of the steel shell segment body frame 31 and formed by mixing polypropylene fibers or vinylon fibers therein. The fire resistant concrete 32 covers the tunnel hollow side of the steel inner flange 43. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a composite segment structure made of steel and concrete used as a lining body in a shield tunnel, and particularly to a composite segment structure excellent in fire resistance.

  Conventionally, synthetic segments have been widely used for lining in various shield tunnels including highways.

  The synthetic segment includes a synthetic segment formed by filling a steel shell composed of a main girder, a joint plate, and a skin plate with filling concrete, or a concrete segment composed of reinforcing steel and concrete.

  Especially for this synthetic segment, it is possible to increase the rigidity of the segment by filling the inner space of the steel shell segment body frame, which is framed by the steel shell, so that the segment thickness can be reduced. It becomes.

  By the way, due to the development of the road network and the increase in the number of tunnels and the increase in traffic volume due to the increase in automobiles, the frequency of fire accidents due to collisions between cars and falls within the road tunnel has increased. The scale of fire accidents is also increasing. In particular, the danger of a disaster when a fire accident occurs in a tunnel due to a tank truck equipped with flammable liquid fuel or liquefied chemicals is far beyond prediction.

  In a fire accident in a tunnel, it is a matter of course that human disasters must be minimized, but there is also a problem of how to protect the tunnel inner wall, especially the segment that is a lining body, from heat.

  On the other hand, the concrete portion and the steel portion of the steel shell are exposed on the inner surface of the shield tunnel in which the composite segments as described above are assembled. In such a tunnel, when a fire breaks out, the rapidly rising high-temperature heat is transmitted directly to the lining concrete in a thermal shock, and moisture contained in the concrete is rapidly evaporated. The concrete may explode and cause a major accident such as a tunnel collapse. In particular, if this composite segment is damaged, the tunnel itself collapses, resulting in an increase in the number of injured persons and obstacles to rescue operations, and a great cost to restore the tunnel. There was also a problem that it was necessary.

  In order to solve such problems, conventionally, a fireproof covering structure as shown in Patent Document 1 has been proposed. This fireproof covering structure includes a block-shaped heat insulating material disposed on the inner peripheral surface of the lining such as a segment, and a metal thin plate in which a large number of holes to be held from the inner peripheral surface side of the heat insulating material are formed. Yes. And this fireproof panel is comprised by fixing this metal thin plate and a heat insulating material to a segment with an anchor pin. Thereby, it becomes possible to improve adhesiveness so that hot air may not enter between a segment and a fireproof panel.

  As another technique using a fireproof panel, for example, as shown in Patent Document 2, a tunnel segment in which a fireproof panel is attached to the entire inner surface of the segment has been proposed.

  Furthermore, as shown in Patent Document 3, for example, a fireproof structure is proposed in which uncured concrete is cast and cured on the surface of a heat insulating member to which a protrusion having a fall prevention mechanism is attached.

  In addition, a tunnel refractory segment is proposed in which concrete is placed on a mold and the refractory coating material is laminated on the concrete surface before the concrete is completely hardened (see, for example, Patent Document 4).

Moreover, in patent document 5, the secondary lining body which has fire resistance performance and impact resistance performance is united with the inside of the segment main body formed by filling concrete etc. inside the steel frame main body and the skin plate. Some segments have been proposed.
JP 2003-129797 A JP 2002-371797 A JP 2000-96995 A JP 2004-3285 A Japanese Patent No. 3302925

  However, in the configuration in which the above-described fireproof panel or secondary lining body is pasted, since it is necessary to paste the fireproof panel over the entire inner periphery of the tunnel, a large amount of fireproof panels are required, which increases the material cost, and consequently There was a problem that the fireproofing cost of the entire shield tunnel increased and the construction period was prolonged.

  Therefore, the present invention has been devised in view of the above-mentioned problems, and provides a composite segment structure made of steel and concrete that can be applied with fire resistance measures in a very short construction period and at a low cost. Objective.

  In order to solve the above-mentioned problems, the present inventor is provided with a refractory concrete in which synthetic fibers such as polypropylene fibers or vinylon fibers that melt and disappear due to heat at the time of fire are mixed in the inner space of the steel shell segment main body frame. A composite segment structure composed of steel and concrete was invented, which was filled and further covered with this refractory concrete up to the air side inside the tunnel of the steel inner flange.

  In the composite segment structure made of steel and concrete according to claim 1 of the present application, a steel shell side frame made of a steel outer flange and a steel inner flange connected via a web is spaced at a predetermined interval on two or four sides. The steel shell segment main body frame that is arranged in parallel and connected between the outer flanges of the steel shell by a skin plate, and the polypropylene that melts and disappears due to heat in a fire, filled in the inner space of the steel shell segment main body frame And refractory concrete mixed with synthetic fiber such as vinylon, and the refractory concrete is further characterized by covering the inner side flange of the steel inner flange.

  The composite segment structure composed of steel and concrete according to claim 2 of the present application is the composite segment structure composed of steel and concrete according to claim 1, wherein the thickness of the concrete covering the inner side of the tunnel of the steel inner flange is 50 mm. It is characterized by being 65 mm or less.

  Further, the composite segment structure made of steel and concrete according to claim 3 of the present application is the composite segment structure made of steel and concrete according to claim 1 or 2, wherein the refractory concrete and the steel inner flange are a stud diver or They are fixed to each other via a spiral dowel or a wire mesh, or fixed to each other by an adhesive.

  Moreover, the synthetic segment structure consisting of steel and concrete according to claim 4 of the present application is the synthetic segment structure consisting of steel and concrete according to claim 1 or 2, wherein the refractory concrete and the steel inner flange insert a non-woven fabric. It is characterized by not sticking.

  In order to solve the above-mentioned problems, the present invention fills the inner space of the steel shell segment body frame with refractory concrete mixed with a synthetic resin such as polypropylene fiber or vinylon fiber, and this refractory concrete is made of steel. It has a composite segment structure that covers the inner flange of the inner flange.

  This eliminates the need for a large number of fireproof panels as in the prior art, and simply covers the fireproof concrete up to the inner side of the tunnel inside the steel inner flange, making it possible to take fireproof measures while reducing fireproof costs. Become.

  Hereinafter, as a best mode for carrying out the present invention, a synthetic segment structure used as a lining body in a shield tunnel will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view of a shield tunnel 3 to which a composite segment structure according to the present invention is applied, and FIG. 2 is a front view thereof. As shown in FIGS. 1 and 2, the shield tunnel 3 is constructed by assembling a cover body in which a plurality of arc-shaped composite segments 4 are connected in a ring shape at a segment joint portion 5 and a ring joint portion 5 ′ on the inner surface of the tunnel. Is done.

  A road floor 15 for driving a car is constructed in the shield tunnel 3 and a building limit 19 exists.

  FIG. 3 is a perspective view of the synthetic segment 4, and FIG. 4 is a view of the steel shell segment from the circumferential direction of the tunnel, with the upper part of the figure showing the natural ground side and the lower part of the figure showing the sky inside the tunnel.

  The composite segment 4 includes a steel shell segment main body frame 31 and a refractory concrete 32 filled in the inner space of the steel shell segment main body frame 31.

  The steel shell segment main body frame 31 has a steel shell side frame 44 composed of a steel outer flange 42 and a steel inner flange 43 joined via a web 41 in a tunnel axis direction, or at a predetermined interval on two sides or four sides. Open and arranged in parallel. The steel shell side frame 44 may be disposed between the segments. A skin plate 45 is fixed between the steel outer flanges 42 of the steel shell side frame 44. The skin plate 45 disposed only on the natural mountain side is formed of a thin steel plate curved in the tunnel circumferential direction. The skin plate 45 is watertightly fixed on the upper surface of the steel outer flange 42 by fixing means such as welding.

  The steel shell segment main body frame 31 employs a configuration in which the refractory concrete 32 is directly exposed to the tunnel inner side 32 ′. The refractory concrete 32 is also configured to cover the tunnel inner side 43 ′ of the steel inner flange 43.

  The refractory concrete 32 is a concrete mixed with a heat-meltable synthetic resin fiber such as polypropylene fiber or vinylon fiber. The concrete composition and production method are, for example, “Tunnel Management Guidelines (Fiber Reinforced Concrete), September 2003, Japan Highway Public Corporation” or “Concrete Structure Fireproof Technology Research Subcommittee Report and Symposium” It may be based on descriptions such as “Papers P72 to P75, Japan Society of Civil Engineers”.

  Synthetic resin fibers such as polypropylene fibers or vinylon fibers mixed in the refractory concrete 32 have a property of melting or disappearing due to heat at the time of fire. Therefore, by mixing them, the inside of the shield tunnel 3 is, for example, 1200 ° C. at the time of fire. Even if it rises above, concrete explosion can be prevented. That is, in this refractory concrete 32, a fine cavity is created by heat in the event of a fire, and this cavity plays a role in relieving the pressure of the water vapor expanded inside, and it is possible to prevent peeling and scattering of the surface layer. It becomes. The refractory concrete 32 can be mixed with these synthetic resin fibers in a concrete plant of a factory.

  4 (a) is an example in which the thickness of the refractory concrete 32 covering the inner side of the tunnel of the steel inner flange 43 is reduced, and FIG. 4 (b) is an example in which the thickness of the refractory concrete 32 is increased. A configured example is shown. In the example of FIG. 4 (a), the thickness of the concrete 32 that covers the tunnel inner side of the steel inner flange 43 is set to 30 mm, for example. Moreover, in the example of FIG.4 (b), the thickness of the concrete 32 which coat | covers the tunnel inner side of the steel inner flange 43 is comprised, for example by 60 mm.

  The thickness of the concrete 32 that covers the inner side of the tunnel of the steel inner flange 43 is most preferably 60 mm. The reason is that the concrete 32 is produced by mixing stone as coarse aggregate and sand as fine aggregate with water. The diameter of this coarse aggregate is about 20 mm at the maximum. If the thickness of the concrete 32 covering the inner side of the tunnel is less than three times the diameter of the coarse aggregate, the integrity with the steel inner flange 43 is hindered, creating the cause of concrete peeling. . In addition, the integrity of the concrete 32 and the coarse aggregate also inhibits the integrity, and defects are easily generated. For this reason, it is desirable that the thickness of the concrete 32 covering the inner side of the tunnel is 60 mm, which is about three times the diameter of the coarse aggregate.

  Further, there is a demand for the temperature of the steel inner flange 43 to be 300 ° C. or less even in a fire. When the temperature rises, the mechanical properties such as tensile strength, compressive strength, Young's modulus, etc. deteriorate when the temperature rises. Especially when the temperature exceeds 300 ° C, both the strength and Young's modulus may fall below 70%. Can no longer be fulfilled. For this reason, it was necessary to suppress the surface temperature of steel materials to 300 degrees C or less. When the thickness of the concrete 32 covering the tunnel inner side of the steel inner flange 43 is thin, it is difficult to control the temperature of the steel inner flange 43 to 300 ° C. or lower. That is, the temperature rise of the steel inner flange 43 can be suppressed as the thickness of the concrete 32 covering the inner side of the tunnel of the steel inner flange 43 increases. For the same reason, there is a demand for the concrete temperature to be 350 ° C. or lower.

FIG. 5 shows the relationship between the maximum temperature and the distance from the heating surface in fiber reinforced concrete. As can be seen from FIG. 5, when the distance from the heating surface exceeds 60 mm, the concrete maximum temperature can be 350 ° C. or less.
If the concrete temperature is suppressed to 350 ° C. or lower, the steel material temperature will inevitably be 300 ° C. or lower. The reason is that the temperature of the steel material does not rise compared to the concrete because the heat conductivity of the steel material is higher than the heat conductivity of the concrete.

In general, concrete becomes neutral when heated by a fire. When CO ₂ gas due to a fire comes into contact with the concrete concrete degraded performance by neutralizing alkaline. That is, the concrete is neutralized, so that the strength is reduced, and the inner steel is rusted by the contact of water and oxygen. However, in a tunnel fire where the maximum temperature of 1200 ° C. continues for about 60 minutes, the neutralization of concrete proceeds only about 50 mm from the surface. For this reason, by configuring the thickness of the concrete 32 covering the inner side of the tunnel at 60 mm, neutralization can be prevented in the remaining 10 mm thick portion even if the surface is neutralized by 50 mm. Rust of the steel inner flange 43 can be prevented.

Furthermore, the fiber filled in the concrete is melted down by heat and becomes pumice. However, in the case of a tunnel fire with a maximum temperature of 1200 ° C. and a duration of about 60 minutes, the fiber is melted from the concrete surface. It is about 50 mm. For this reason, by configuring the thickness of the concrete 32 covering the inner side of the tunnel to be 60 mm, it is possible to prevent pumice formation in the remaining 10 mm thick portion even if 50 mm fibers are melted from the surface. It becomes.
In addition, when the thickness of the concrete 32 covering the inner side of the tunnel exceeds 65 mm, the material cost increases and the inner diameter of the tunnel becomes smaller. Therefore, it is desirable that the maximum thickness is about 65 mm. Moreover, if the thickness of the concrete 32 covering the inner side of the tunnel is at least about 50 mm, the above-described problems can be cleared, and therefore, it may be in the range of about 50 to 65 mm.

  The refractory concrete 32 covers the steel inner flange 43. For this reason, it becomes possible to improve the fire resistance with respect to the steel shell segment main body frame 31 similarly.

  The refractory concrete 32 and the steel inner flange 43 have different coefficients of thermal expansion. Therefore, when they are exposed to high heat due to a fire, the refractory concrete 32 and the steel inner flange 43 are different from the steel inner flange 43 in the refractory concrete 32. There is a possibility that the adhered portion may be peeled off.

  For this reason, as shown in FIG. 6, the boundary surface 51 between the refractory concrete 32 and the steel inner flange 43 may be fixed to each other via a stud or bell. Further, an adhesive may be provided on the boundary surface 51 so that the refractory concrete 32 and the steel inner flange 43 are fixed to each other. Moreover, it is good also as a structure which does not mutually adhere by inserting a nonwoven fabric etc. between the refractory concrete 32 and the steel inner flange 43. FIG. Thereby, generation | occurrence | production of a crack can be prevented in the adhesion part of the refractory concrete 32 and the steel inner flange 43. FIG.

  Further, instead of providing various kinds of jibels or adhesives to these boundary surfaces 51, for example, a stainless steel wire mesh 52 may be provided in the vicinity of the refractory concrete 32 inside the tunnel. This also makes it possible to prevent the occurrence of cracks. Further, as an example of the wire mesh 52, for example, it may be applied as a wire mesh in which steel bars are arranged in a lattice shape, or may be applied as an expanded metal or a lath. That is, the wire mesh 52 may be configured in any mesh size as long as it is a lattice shape, and the vertical and horizontal stripes may not be fixed to each other by welding or the like.

  In addition, as shown in FIG.4 (b), when it is desired to make the surface temperature of the steel inner flange 43 into 350 degrees C or less, the thickness of the refractory concrete 32 is comprised thickly. Further, as shown in FIG. 4 (a), the surface temperature of the steel inner flange 43 is, for example, 350 ° C. or more. However, when the high temperature proof stress of the synthetic segment can be maintained, the refractory concrete 32 is made thin. Can be made cheaper.

  Moreover, in embodiment mentioned above, although the steel shell segment 4 was previously manufactured in the factory, and it demonstrated supposing the case where these are conveyed and assembled on the spot, this invention is not limited to this case. . For example, you may make it produce on-site as a post-installation of shield construction. Moreover, although the description has been made assuming that the shape of the steel shell segment 4 is an arc plate, it is not limited to such a case, and may be configured in a flat plate shape according to the shape of the tunnel. Of course.

1 is a perspective view of a shield tunnel to which a composite segment structure according to the present invention is applied. It is a front view of the shield tunnel to which the synthetic segment structure concerning the present invention is applied. It is a perspective view of the synthetic segment to which this invention is applied. It is a figure from the tunnel peripheral direction of the synthetic | combination segment to which this invention is applied. It is a figure which shows the relationship of the maximum temperature with respect to the distance from the heating surface in fiber reinforced concrete. It is a figure for demonstrating the fixing method of the interface of a refractory concrete and steel inner flanges.

Explanation of symbols

2 Segment ring 3 Shield tunnel 4 Composite segment 11 Ground 15 Road floor 19 Building limit 31 Steel shell segment frame 32 Refractory concrete 41 Web 42 Steel outer flange 43 Steel inner flange 44 Steel shell side frame 45 Skin plate

Claims (4)

A steel shell side frame composed of a steel outer flange and a steel inner flange connected via a web is arranged in parallel at a predetermined interval on two or four sides, and a skin plate is provided between the steel shell outer flanges. Steel shell segment body frame connected by
The inner space of the steel shell segment body frame is filled with refractory concrete mixed with synthetic fibers such as polypropylene and vinylon that melts and disappears by heat in the event of a fire,
The refractory concrete is a synthetic segment structure made of steel and concrete, characterized in that it further covers the inner side flange of the steel inner flange. The composite segment structure comprising steel and concrete according to claim 1, wherein the thickness of the concrete covering the tunnel inner side of the steel inner flange is not less than 50 mm and not more than 65 mm. The steel and concrete according to claim 1 or 2, wherein the refractory concrete and the steel inner flange are fixed to each other through a stud or bell or a wire mesh, or fixed to each other by an adhesive. A synthetic segment structure consisting of The composite segment structure comprising steel and concrete according to claim 1 or 2, wherein the refractory concrete and the steel inner flange are not fixed by inserting a nonwoven fabric.

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