JP2020063613A - Tunnel composite segment and tunnel - Google Patents

Abstract

To provide a tunnel composite segment having strength and heat resistance required for the tunnel composite segment, and a tunnel.SOLUTION: A tunnel composite segment 1 is provided with a steel shell 2 and a solidified body 3 filled into the steel shell 2 and also the solidified body 3 includes blast furnace water-granulated slags, and further as the solidified body for a structure is made by using the enhancement of strength due to a latent hydraulic property of a vitreous substance of the blast furnace water-granulated slags, its own porous structure, and air permeability due to gaps caused between particles of the blast furnace water-granulated slags, the required strength and heat resistance necessary to the tunnel composite segment can be obtained.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to a tunnel composite segment and a tunnel in which a solidified material is filled inside a steel shell.

  Conventionally, as an example of a segment used for constructing a tubular structure such as a shield tunnel, a synthetic segment in which a steel shell is filled with concrete and hardened is known. In such a composite segment, concrete resists a compressive load and a steel shell resists a tensile load, whereby high yield strength and high rigidity are obtained. As such a synthetic segment, for example, one described in Patent Document 1 is known.

The composite segment described in Patent Document 1 includes a steel shell formed of a pair of main girders, a joint plate, and a skin plate, and concrete filled inside the steel shell. Inside the concrete, a plurality of first main rebars extending in the tunnel radial direction in the tunnel circumferential direction are arranged at predetermined intervals in the tunnel axial direction, and at both ends of the array of the plurality of first main rebars. The arranged first main rebar is characterized in that the distance from the main girder is equal to or greater than the arrangement distance.

Although not a composite segment, the one described in Patent Document 2 is known as an example of a fireproof segment for a shield tunnel. The fireproof segment for a shield tunnel described in Patent Document 2 includes a segment main body in which a reinforcing steel material such as a reinforcing bar is embedded on the outer surface side of the segment, and a fireproof unreinforced concrete that does not have the reinforcing steel material on the inner surface side of the segment main body portion. It is configured by integrally providing layers. The refractory unreinforced concrete layer is formed by molding high refractory cement such as alumina cement or alkali slag cement, and massive concrete slag, ferronickel slag, chamotte, or refractory concrete using highly heat-insulating aggregate such as igneous rock. ..

JP, 2005-78534, A JP, 2002-194996, A

By the way, a conventional synthetic segment has a structure in which concrete is filled inside a steel shell formed of steel material, but when exposed to a high temperature environment such as a fire, the solidified solidified concrete does not have air permeability. Since it is bad, free water inside may explode or the strength of the steel material may be reduced.
From the viewpoint of structural safety, in order to avoid such a situation, an insulating air layer is generated at high temperature by mixing organic fiber into concrete, or a surface layer such as rock wool or gypsum board to protect the main body structure. By applying a fireproof coating, it actively creates an air layer for heat insulation. However, in this case, in addition to the main body structure, it is necessary to add fireproof materials and parts, and in order to avoid the extension of the construction period due to the additional parts and the additional process, a material having a certain strength and heat insulation is required. Has been.

Therefore, the present inventor has conducted diligent research in order to develop a synthetic segment having strength and heat resistance required for a tunnel segment. As a result, a latent hydraulic property is obtained by mixing with a cement additive (hardening material). It was conceived to apply the solidified body of granulated blast furnace slag, which exhibits the above properties and has high air permeability, as the main body structure (filling material) of a synthetic segment that has not been used in the past.
Granulated blast furnace slag has strength manifested by particles binding together and hardening due to hydraulic properties in water and an alkaline environment.Furthermore, the material itself has a porous structure and there are gaps between the particles of the solidified body. Yes, it has an air layer.
Therefore, it can be used as a strength member that bears compressive force, and by utilizing the air permeability of granulated blast furnace slag, heat resistance can be imparted even if the conventionally used organic fibers and surface refractory layer are omitted, so in the event of a fire Also exerts a heat insulating effect.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a tunnel synthetic segment and a tunnel having the strength and heat resistance required for the tunnel synthetic segment.

To achieve the above object, the tunnel synthetic segment of the present invention is a tunnel synthetic segment comprising a steel shell and a solidified body filled inside the steel shell,
The solidified body contains granulated blast furnace slag.
In this case, it is preferable to include granulated blast furnace slag as fine aggregate.

Here, the synthetic segment includes a synthetic segment for tunnels used for construction of shield tunnels, a synthetic segment for tunnels used for construction of excavated tunnels, and a synthetic segment for tunnels used for construction of other tunnels. Any segment will do.
Further, the steel shell, a pair of main girders arranged at a predetermined interval in the tunnel axis direction, a joint plate that connects the end portions of the pair of main girders, and is fixed to the main girder and the joint plate, It may have a skin plate covering the natural ground side, or may have a main girder and a joint plate but not a skin plate. At this time, the main girder may be a flat plate, or may be an I-shape or a U-shape in which steel plates are further provided at both ends of the main girder in the tunnel radius direction.
Further, the solidified body may be composed only of granulated blast furnace slag, or may contain a hardening material or blast furnace slowly cooled slag as described later.

Granulated blast furnace slag does not crystallize by rapidly cooling molten blast furnace slag with high-pressure water, and most of it becomes vitreous and has a porous structure with voids. The glass property of the granulated blast furnace slag has a latent hydraulic property in which the hydration reaction proceeds due to the reaction with a stimulant such as alkalinity to cure and increase the strength. Furthermore, the melting point of granulated blast furnace slag is higher than that of natural sand, and the fire resistance of the material is also high. It is also chemically stable, has no alkali-aggregate reaction, and has less drying shrinkage than natural aggregates. In addition, the particle size of the granulated blast furnace slag is generally about 5 mm or less, and the particles are bonded and hardened, so that a gap is likely to be generated between the particles.
Therefore, in the present invention, since the solidified body filled in the steel shell contains granulated blast furnace slag, the strength increase due to latent hydraulicity of the vitreous granulated blast furnace slag and its porous structure and granulated blast furnace slag. Since it becomes a structural solidified body utilizing the air permeability due to the gaps generated between the particles, it is possible to obtain the strength and heat resistance required for the tunnel synthetic segment.
Further, since the granulated blast furnace slag is porous, the structure of the solidified body containing the granulated blast furnace slag is also porous and the air permeability is improved, so that there is no problem of explosion of free water inside.
Furthermore, due to the heat insulating effect of the solidified body of porous granulated blast furnace slag, special additives such as organic fibers and heat insulating coating materials such as rock wool and gypsum board, which have been used to improve heat insulating property, have been omitted. can do. As a result, it is possible to obtain a composite segment for tunnel which is highly economical and easy to construct and has excellent fire resistance.

  Moreover, in the said structure of this invention, five surfaces except the tunnel inner peripheral surface side of the said steel shell may be covered with steel material.

  According to such a configuration, the steel shell is covered with steel on five sides except the tunnel inner peripheral surface side. Therefore, when the tunnel composite segment is manufactured in advance in a factory or the like, the steel shell is also used as a formwork. However, the granulated blast furnace slag can be easily charged into the inside of the tunnel from the opening facing the inner peripheral surface side.

Moreover, in the said structure of this invention, the hardening material may be contained in the said solidification body.
The hardening material may include at least one selected from Portland cement, blast furnace slag cement, and steelmaking slag fine powder.
If steelmaking slag fine powder is used as the hardening material contained in the solidified body, the strength can be further increased. In the coarse aggregate steelmaking slag, quick lime may be present internally, and when the quicklime reacts with water, it becomes calcium hydroxide and expands. Therefore, the steelmaking slag is used as a fine powder. As described above, by using the steelmaking slag fine powder, it is possible to suppress the expansion after the construction of the solidified body using the steelmaking slag fine powder as the hardening material.

  According to such a configuration, since the solidified body contains the hardening material, the hardening of the solidified body is promoted, the mechanical strength of the solidified body is increased, and the structural function of the synthetic segment can be strengthened.

  Moreover, in the said structure of this invention, a blast furnace slow cooling slag may be further contained in the solidified body.

  According to such a configuration, since the blast furnace slowly cooled slag has a larger particle size than the granulated blast furnace slag, it can function as a coarse aggregate and can obtain a large supporting force.

  Further, the tunnel of the present invention is characterized by including one or more pieces of the above-described composite segment.

  In the present invention, a tunnel having the strength and heat resistance required for the tunnel can be easily constructed.

  According to the present invention, a tunnel synthetic segment and a tunnel having the strength and heat resistance required for the tunnel synthetic segment can be obtained.

The 1st Embodiment of this invention is shown and it is a perspective view of a synthetic | combination segment. It is an enlarged schematic diagram of the structure of a solidified body, (a) is an enlarged schematic diagram of the structure of a solidified body containing granulated blast furnace slag, (b) is an enlarged schematic view of the structure of a solidified body made of conventional concrete. . The 1st Embodiment of this invention is shown, Comprising: It is a perspective view which shows schematic structure of a tunnel. The 2nd Embodiment of this invention is shown and it is a side sectional view of a synthetic segment. FIG. 3 is a front sectional view of the same composite segment. The 3rd Embodiment of this invention is shown and it is a perspective view of a synthetic segment. The 4th Embodiment of this invention is shown, Comprising: It is a perspective view which shows schematic structure of a tunnel.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a perspective view showing a tunnel composite segment (hereinafter referred to as a composite segment) according to the first embodiment.
The composite segment 1 of the present embodiment is a segment used when constructing a shield tunnel, and includes a steel shell 2 and a solidified body 3 as a filling material filled inside the steel shell 2. ing. Although FIG. 1 shows a state where the solidified body 3 is filled in a part of the inside of the steel shell 2, the solidified body 3 is actually filled in the entire inside of the steel shell 2.

  The steel shell 2 connects a pair of main girders 5 and 5 arranged at a predetermined interval in the tunnel axis direction with the end portions of the pair of main girders 5 and 5 and also has a pair of elongated gages in the tunnel axis direction. The joint plates 6 and 6 and the main girder 5 and the joint plate 6 are provided with a skin plate 7 that covers the natural ground side.

The main girders 5 and 5 are made of an arc plate-shaped steel material (steel plate, I-shape, U-shape) in a front view (view in the tunnel axial direction), and are arranged so as to be convex outward in the tunnel radial direction. There is.
The joint plates 6 and 6 are made of a rectangular plate-shaped steel material (steel plate) that is long in the tunnel axis direction. One end of one joint plate 6 is joined by welding to one end of one joint plate 6, One end of the other main girder 5 is joined to the other end of the one joint plate 6 by welding. The other end of the one main girder 5 is joined to one end of the other joint plate 6 by welding, and the other end of the other main girder 5 is joined to the other end of the other joint plate 6 by welding. ing.
Thus, the pair of main girders 5 and 5 and the pair of joint plates 6 and 6 form a rectangular frame that is convex outward in the radial direction of the tunnel.

The skin plate 7 is formed of a steel material (steel plate) having an arc plate shape, and is arranged so as to be convex outward in the radial direction of the tunnel. The longitudinal dimension of the skin plate 7 is substantially equal to the longitudinal dimension of the main girder 5 on the outer side in the tunnel radial direction, and the lateral dimension of the skin plate 7 is equal to the longitudinal dimension of the joint plate 6. It is almost equal. The edge of the skin plate 7 in the longitudinal direction is joined to the edge of the main girder 5 in the longitudinal direction by welding, and the edge in the lateral direction is joined to the edge of the joint plate 6 in the longitudinal direction by welding. As a result, the main girder 5 and the joint plate 6 are fixed.
As described above, in the present embodiment, the steel shell 2 is covered with the steel material (main girders 5, 5, the joint plates 6, 6 and the skin plate 7) on five surfaces except the tunnel inner peripheral surface side.

Further, a plurality of vertical ribs 10 are provided inside the steel shell 2. That is, first, the vertical rib 10 extends in a direction intersecting with the main girder 5. Specifically, the vertical ribs 10 are formed of a rectangular plate-shaped steel material (steel plate), and are arranged between the main girders 5 and 5 at substantially right angles to the main girders 5 and 5. Such vertical ribs 10 are arranged substantially parallel to the radial direction of the tunnel, and are arranged at predetermined intervals in the longitudinal direction of the main girder 5, that is, the circumferential direction of the tunnel.
Further, one end of the vertical rib 10 is joined to one main girder 5 by welding, and the other end of the vertical rib 10 is joined to the other main girder 5 by welding. Further, the outer edge of the vertical rib 10 in the tunnel radial direction is joined to the inner surfaces of the skin plate 7 and the main girder 5 by welding. In this way, the vertical ribs 10 are arranged inside the steel shell 2 at predetermined intervals in the longitudinal direction of the main girder 5, and are fixed to the main girder 5 and the skin plate 7. Further, in the state where the vertical ribs 10 are fixed to the steel shell 2, the inner edge portions of the vertical ribs 10 in the tunnel radial direction are located outside the inner radial edges of the main girder 5 and the joint plate 6 in the tunnel radial direction. ing. That is, the vertical ribs 10 are arranged outside the opening surface of the steel shell 2 in the tunnel radial direction.

  Further, the vertical ribs 10 may be provided with a plurality of circular openings 11 at predetermined intervals in the tunnel axial direction, that is, the longitudinal direction of the vertical ribs 10, and are arranged inward in the tunnel radial direction. In this case, the openings 11 respectively provided in the plurality of vertical ribs 10 are arranged to face each other in the tunnel circumferential direction, and the reinforcing bars 12 are inserted into the plurality of openings 11 arranged to face each other. The reinforcing bar 12 extends in the tunnel circumferential direction, one end of the reinforcing bar 12 is fixed to the inner surface of one joint plate 6 by welding, and the other end of the reinforcing bar 12 is the inner surface of the other joint plate 6. It is also possible to fix it by welding or to fix it to the filling material inside the steel shell without welding by bending the reinforcing bar 12 or ensuring a fixed fixing length. Further, although not shown, the vertical rib 10 may be provided with a notch on the inner side or the outer side in the radial direction of the tunnel in order to ensure filling, in addition to the opening 11.

Inside the steel shell 2 provided with the main girders 5, 5, the joint plates 6, 6, and the skin plate 7, a solidified body 3 as a filling material is filled. The solidified body 3 is adhered to the inner surface of the main girder 5, the inner surface of the joint plate 6, the inner surface of the skin plate 7 and the outer peripheral surface of the reinforcing bar 12 by hardening.
The solidified body 3 contains granulated blast furnace slag as fine aggregate, and when the solidified body 3 is filled in the steel shell 2, for example, as shown in FIG. 1, the steel shell 2 is arranged in a ship shape. That is, by arranging the skin plate 7 facing downward, the steel shell 2 is also used as a mold, and the inside of the steel shell 2 is filled with a solidifying material having fluidity before hardening of the solidified body 3. Is done by doing. In this case, the solidifying material is filled so that the surface thereof is substantially flush with the virtual curved plane formed by the inner edge of the main girder 5 and the inner edge of the joint plate 6.

In this case, granulated blast furnace slag is spread until the inner space becomes the same as the virtual curved plane of the steel shell 2 inside the steel shell 2 which is also used as a formwork, and further, a predetermined amount of water, Portland cement and blast furnace are used. Cement-based additives (hardening material) such as slag cement and steelmaking slag fine powder and, if necessary, blast furnace slowly cooled slag are mixed and solidified.
Alternatively, granulated blast furnace slag and a predetermined amount of water, Portland cement, blast furnace slag cement, cement additive (hardening material) such as steelmaking slag fine powder, and blast furnace slowly cooled slag if necessary, kneading, A solidified body (solidified material) having a certain fluidity is filled inside the steel shell 2 until the inner space surface becomes the same as the virtual curved plane of the steel shell 2.
Since the vertical ribs 10 are provided inside the steel shell 2, the solidifying material is filled after the vertical ribs 10 are provided.

The granulated blast furnace slag, when producing iron in a blast furnace, is a molten blast furnace slag that is generated at the same time as pig iron, which is the source of iron, is rapidly cooled with high-pressure water, and is not crystallized by being rapidly cooled. Most of the structure is glassy and has a porous structure with voids.
The glass property of the granulated blast furnace slag has a latent hydraulic property in which the hydration reaction proceeds due to the reaction with a stimulant such as alkalinity to cure and increase the strength. Furthermore, the melting point of granulated blast furnace slag is higher than that of natural sand, and the fire resistance of the material is also high. Further, granulated blast furnace slag is chemically stable, has no alkali aggregate reaction, and has a smaller drying shrinkage than natural aggregate. In addition, the particle size of the granulated blast furnace slag is generally about 5 mm or less, and the particles are bonded and hardened, so that a gap is likely to be generated between the particles.

FIG. 2A is an enlarged schematic diagram of the structure of a solidified body containing granulated blast furnace slag. The granulated blast furnace slag 20a as fine aggregate in this figure has a particle size of about 5 mm or less. In such granulated blast furnace slag 20a, particles are combined with each other and solidified, and a large number of gaps are generated between the particles. (In the figure, particles are not shown in contact with each other, but particles are in contact with each other when they are filled.) This gap becomes an air layer, which has high air permeability and exerts a heat insulating effect. .
On the other hand, concrete, which is generally used as a filling material for synthetic segments, is dense and dense with no coarse aggregates 20b, fine aggregates (sand, etc.) or cement, as shown in the enlarged schematic view of FIG. 2 (b). It is really filled.

In the synthetic segment 1 in which the solidified body 3 containing the granulated blast furnace slag is filled in the steel shell 2, the strength increase due to the latent hydraulic property of the vitreous granulated blast furnace slag contained in the solidified body 3 is increased. And the porous solid structure and the structural solidified body utilizing the air permeability due to the gaps formed between the particles of the granulated blast furnace slag, the strength and heat resistance required for the synthetic segment can be obtained.
Further, since the granulated blast furnace slag is porous, the structure of the solidified body 3 including the granulated blast furnace slag is also porous and the air permeability is improved, so that there is no problem of explosion of free water inside.
Furthermore, due to the heat insulating effect of the solidified body of porous granulated blast furnace slag, special additives such as organic fibers and heat insulating coating materials such as rock wool and gypsum board, which have been used to improve heat insulating property, have been omitted. can do. As a result, it is possible to obtain a composite segment for tunnel which is highly economical and easy to construct and has excellent fire resistance.

Further, in the present embodiment, the hardened material may be contained in the solidified body 3 containing the granulated blast furnace slag. The hardening material preferably contains at least one selected from Portland cement, blast furnace slag cement, and steelmaking slag fine powder.
If the steelmaking slag fine powder is used as the hardening material contained in the solidified body 3, the strength can be further increased. In the coarse aggregate steelmaking slag, quick lime may be present internally, and when the quicklime reacts with water, it becomes calcium hydroxide and expands. Therefore, the steelmaking slag is used as a fine powder. As described above, by using the steelmaking slag fine powder, it is possible to suppress the expansion after the construction of the solidified body 3 using the steelmaking slag fine powder as the hardening material.
In this way, by including the hardening material in the solidified body 3, the hardening of the solidified body 3 is promoted, the mechanical strength of the solidified body 3 is increased, and the structural function of the synthetic segment 1 can be strengthened.

  Further, the solidified body 3 may further contain blast furnace slowly cooled slag. Since the blast furnace slowly cooled slag has a larger particle size than the granulated blast furnace slag, the blast furnace slowly cooled slag can obtain a large supporting force as coarse aggregate.

The tunnel 15 is constructed by joining the composite segment 1 of the present embodiment in the tunnel axial direction and the tunnel circumferential direction as shown in FIG.
The tunnel 15 is provided in an excavation hole formed by excavating the ground or the like by the shield method. Further, the plurality of composite segments 1 are joined in the tunnel circumferential direction to construct the segment ring 1L, and the plurality of segment rings 1L are joined in the tunnel axial direction to construct the cylindrical tunnel 15. .
By using the synthetic segment 1 in this way, the tunnel 15 having the strength and heat resistance required for the tunnel can be easily constructed.
Further, when constructing (constructing) the tunnel 15, the synthetic segment 1 may be provided at a required location, and a normal synthetic segment using concrete as a filling material may be provided at other locations. In short, the tunnel 15 may include one or more pieces of the composite segment 1.

(Second embodiment)
4 and 5 show a composite segment according to the second embodiment. FIG. 4 is a side sectional view of the composite segment (a sectional view along the tunnel axis direction), and FIG. 5 is a front sectional view of the composite segment (a tunnel). It is sectional drawing which follows the direction orthogonal to an axial direction.
The synthetic segment 21 of the present embodiment is different from the synthetic segment 1 of the first embodiment in the arrangement of the reinforcing bars and the fixing structure of the reinforcing bars provided inside the steel shell 2. Therefore, this point will be described below. However, the same components as those in the first embodiment may be designated by the same reference numerals and the description thereof may be omitted.

In the composite segment 21 according to the second embodiment, inside the steel shell 2, a plurality of first reinforcing bars 22 extending in the tunnel circumferential direction on the tunnel inner space G side are provided at predetermined intervals in the tunnel axial direction, and on the natural ground F side. A plurality of second reinforcing bars 23 extending in the tunnel circumferential direction are provided at predetermined intervals in the tunnel axial direction. The plurality of first reinforcing bars 22 and the plurality of second reinforcing bars 23 are surrounded by a predetermined number of hoop bars 24, and the hoop bars 24 are fixed to a fixing member 25 joined to the skin plate 7.
Further, the plurality of first reinforcing bars 22 and the plurality of second reinforcing bars 23 are arranged inside the hoop reinforcing bars 24, and the plurality of first reinforcing bars 22 and the plurality of second reinforcing bars 22 are surrounded by the hoop reinforcing bars 24 and bound together. ing.

The fixing member 25 is composed of a headed stud dowel, a perforated steel plate dowel, chevron steel, and the like, and is arranged in plural at predetermined intervals in the tunnel circumferential direction and the tunnel axial direction. The spacing between the fixing members 25, 25 adjacent to each other in the tunnel circumferential direction is set to be substantially the same as the spacing between the hoop streaks 24, 24 adjacent to each other in the tunnel circumferential direction.
4 and 5 show the case where the fixing member 25 is a headed stud dowel, the leg portion 25a of the headed stud dowel is welded to the inner space G side of the skin plate 7, and the head portion 25b is connected to the hoop muscle 24. It is joined. The fixing member 25 and the hoop streak 24 are joined by, for example, welding or binding with a binding wire.
Further, between the fixing member 25 and the hoop muscle 24, the hoop muscle 24 is inserted through a hole formed in the fixing member 25, or the hoop muscle 24 is hooked on a protrusion provided on the fixing member 25. It may be joined.
In this way, the hoop muscle 24 is fixed to the fixing member 25, and the first reinforcing bar 22, the second reinforcing bar 23, and the skin plate 7 are connected via the hoop muscle 24 and the fixing member 25.

Also in such a synthetic segment 21, as in the first embodiment, the solidified body 3 containing the granulated blast furnace slag as fine aggregate is filled inside the steel shell 2. Further, similarly to the first embodiment, the hardening material may be contained in the solidified body 3 containing the granulated blast furnace slag. The hardening material preferably contains at least one selected from Portland cement, blast furnace slag cement, and steelmaking slag fine powder. Further, the solidified body 3 may further contain blast furnace slowly cooled slag as coarse aggregate.
Moreover, a tunnel is constructed by joining the composite segments 21 of the present embodiment in the tunnel axial direction and the tunnel circumferential direction.
According to this embodiment, the same effect as that of the first embodiment can be obtained.

(Third Embodiment)
FIG. 6 is a perspective view showing a composite segment according to the third embodiment. Although FIG. 6 shows a state in which the solidified body 3 is filled in a part of the inside of the steel shell 2, the solidified body 3 is actually filled in the entire inside of the steel shell 2.
The synthetic segment 26 of the present embodiment is different from the synthetic segments 1 and 21 of the first and second embodiments in that the vertical rib 27 is provided inside the steel shell 2. This point will be described, and the same configurations as those of the first embodiment will be denoted by the same reference numerals and the description thereof may be omitted.

A plurality of vertical ribs 27 are provided in parallel with the joint plate 6 at predetermined intervals in the tunnel circumferential direction between the main girders 5, 5, and both ends of the vertical rib 27 are welded to the main girders 5, 5. It is fixed. The vertical ribs 27 are rod-shaped or tubular-shaped and have a top portion on the inner side in the radial direction of the tunnel formed in an arcuate cross section and extending in the tunnel axial direction. Further, unlike the first and second embodiments, no reinforcing bar is provided inside the steel shell 2.
In addition, a hole for inserting a reinforcing bar is formed in each of the vertical ribs 27 so as to correspond to the circumferential direction of the tunnel, a reinforcing bar extending in the circumferential direction of the tunnel is inserted through the hole, and both ends of the reinforcing bar are welded to the joint plate 6 or the like. Reinforcing rods may be provided inside the steel shell 2 by fixing with. Alternatively, the vertical ribs 27 may not be provided with holes for inserting the reinforcing bars, and the reinforcing bars may be placed on the vertical ribs 27 and installed.

In such a synthetic segment 26 as well, as in the first and second embodiments, the solidified body 3 containing the granulated blast furnace slag as fine aggregate is filled inside the steel shell 2. Further, similarly to the first and second embodiments, a hardening material may be contained in the solidified body 3 containing the granulated blast furnace slag. The hardening material preferably contains at least one selected from Portland cement, blast furnace slag cement, and steelmaking slag fine powder. Further, the solidified body 3 may further contain blast furnace slowly cooled slag as coarse aggregate.
Moreover, a tunnel is constructed by joining the composite segments 26 of the present embodiment in the tunnel axial direction and the tunnel circumferential direction.
According to the present embodiment, it is possible to obtain the same effects as those of the first and second embodiments.

In the first to third embodiments described above, the ground side surface of the steel shell 2 is covered with the skin plate 7, but the skin plate 7 may be omitted. That is, the steel shell 2 may be formed in a rectangular frame shape by the pair of main girders 5, 5 and the pair of joint plates 6, 6.
In this case, since the steel shell 2 cannot be directly used as a mold, the steel shell 2 is placed on the mold stand, and one of the open sides of the steel shell 2 is closed by the mold stand. After that, the solidified body 3 may be filled from the other surface.

(Fourth Embodiment)
FIG. 7 shows a tunnel having a rectangular cross section constructed by using the composite segment 31 of the third embodiment. The tunnel 40 is provided in an excavation portion 38a formed by excavating the existing ground 38.
The tunnel 40 is constructed by joining a plurality of composite segments 31 in the tunnel circumferential direction to form a substantially rectangular segment ring, and joining the plurality of segment rings in the tunnel axial direction to connect them. Further, the tunnel 40 secures a predetermined internal space S by connecting a plurality of composite segment rings in the tunnel axial direction, and has a predetermined extension in the tunnel axial direction.
The segment ring is formed by, for example, a method of joining the synthetic segments 31 while stacking the synthetic segments 31 from below the cut-and-cut portion 38a toward above. Further, the segment rings are joined in the tunnel axis direction by joining at the joining portions adjacent to each other in the tunnel axis direction.

The composite segment 31 has main girders 35 provided at both ends in the tunnel axial direction, joint plates 36, 36 provided at both ends in the tunnel circumferential direction, and on the opposite side of the internal space S of the tunnel 40, on the outer circumferential side of the tunnel 40. It has a steel shell 32 with a skin plate 37 provided.
One or more composite segments 31 are used in each of the top slab, the side slabs on both sides, and the bottom slab of the tunnel 40. The composite segment 31 is formed in a substantially L shape, a vertically long rectangle, a U-shape, and the like in a front view (view in the tunnel axial direction).

  Further, the steel shell 32 of the composite segment 31 is formed in a substantially U-shaped cross section, and its opening is directed to the inner side of the tunnel (inner space S side). The steel shell 32 is covered with a main girder 35, a joint plate 36, and a skin plate 37 except for the opening. That is, the steel shell 32 is covered with the steel material (main girder 35, joint plate 36, and skin plate 37) on the surface other than the tunnel inner peripheral surface side (tunnel inner side). Further, inside the steel shell 32, reinforcing bars (not shown) are provided along the tunnel circumferential direction.

Also in such a synthetic segment 31, as in the first to third embodiments, the solidified body 3 containing the granulated blast furnace slag as fine aggregate is filled inside the steel shell 32. Further, similarly to the first and second embodiments, a hardening material may be contained in the solidified body 3 containing the granulated blast furnace slag. The hardening material preferably contains at least one selected from Portland cement, blast furnace slag cement, and steelmaking slag fine powder. Further, the solidified body 3 may further contain blast furnace slowly cooled slag as coarse aggregate.
According to this embodiment, the same effects as those of the first to third embodiments can be obtained.

  In the present embodiment, the case where the solidified body 3 containing the granulated blast furnace slag as fine aggregate is filled inside the steel shells 2, 32 of the synthetic segments 1, 21, 31 has been described as an example. INDUSTRIAL APPLICABILITY The invention can be applied as a structural material in which a solidified body containing granulated blast furnace slag is filled inside a steel shell that constitutes a structure such as caisson constructed in water or underground.

1,2,26,31 Synthetic segment for tunnel 2,32 Steel shell 3 Solidified body 5,35 Main girder (steel material)
6,36 Joint plate (steel material)
7,37 Skin plate (steel material)
15,40 tunnel

Claims (6)

A synthetic segment for a tunnel comprising a steel shell and a solidified body filled inside the steel shell,
A synthetic segment for a tunnel, wherein the solidified body contains granulated blast furnace slag.   The composite segment for a tunnel according to claim 1, wherein the steel shell has five surfaces covered with a steel material except for the inner peripheral surface side of the tunnel.   The tunnel synthetic segment according to claim 1 or 2, wherein the solidified body contains a hardening material.   The synthetic segment for tunnel according to claim 3, wherein the hardening material contains at least one selected from Portland cement, blast furnace slag cement, and steelmaking slag fine powder.   The tunnel synthetic segment according to any one of claims 1 to 4, wherein the solidified body further contains blast furnace slowly cooled slag.   A tunnel comprising one or more pieces of the synthetic segment according to any one of claims 1 to 5.

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