JPH0359300A - Synthetic segment - Google Patents

Abstract

PURPOSE:To improve high strength, high rigidity and economy by providing steel plates folded on both ends face to face on the inner side and the natural ground side of a tunnel, providing dowels inside, and placing concrete. CONSTITUTION:Bolt boxes 5 and 6 and a grout injection hole 7 are provided at present positions on an inside steel plate 2 constituted of a tunnel inside skin plate 2a and joint plates 2b and an outside steel plate 3 constituted of a tunnel natural ground side skin plate 3a and end plates 3b. A number of headed dowels 9 are provided on mating faces of steel plates 2 and 3, and projections 11 and 12 are provided on both faces. Concrete is placed between steel plates 2 and 3 to form a synthetic segment 1. The steel plate section copes with the tensile force, the concrete section copes with the compressing force, the strength and tenacity are improved, and the rigidity as a segment can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a synthetic segment for tunnel lining used in shield construction methods and the like.

[Conventional technology]

The shield method is often used when constructing tunnels on soft ground or in urban areas where ground subsidence is a concern.

The shield construction method is a construction method in which a shield machine is propelled underground, and excavation and lining work is carried out inside the tunnel while preventing the collapse of earth and sand, thereby constructing tunnel a (see Figure 9). At this time, a lining material is used for the purpose of withstanding external forces such as earth pressure and water pressure from the ground around the tunnel 8, receiving the reaction force of the shield machine, and securing a predetermined space inside the tunnel.

This lining material is classified into copper segments, reinforced concrete segments, etc. based on the materials used (in Fig. 9, C indicates the inner tunnel side, and d indicates the tunnel side).

FIG. 10 shows a typical example of the steel segment 21, which includes a steel skin plate 22, a main girder 23, a joint plate 24,
It is composed of vertical ribs 25 and the like, and these are assembled mainly by welding. Since the steel segment 21 is made of uniform material and has guaranteed strength, it has stable quality, is relatively lightweight, and has good workability. However, when the jerking thrust becomes large, buckling of the skin plate 22 tends to occur.
Appropriate corrosion protection may also be required.

Figure 11 shows a typical example of a reinforced concrete segment 31, which is made by arranging reinforcing bars 32 in a designed amount in a formwork, and pouring concrete 33 that exhibits a predetermined strength into the formwork. . The reinforced concrete segment 31 has excellent durability and compression resistance, so there is no concern about buckling due to jack thrust, etc., but it is relatively heavy and has low tensile strength, and the concrete 33
Parts of the structure are easily damaged, so care must be taken when transporting and handling during construction.

In addition, there are base segments that combine steel and concrete; for example, in Japanese Patent Application Laid-Open No. 61-286497, non-shrinkable unreinforced concrete is injected under pressure into a hexahedral closed steel shell formed from steel. A synthetic segment is disclosed.

(Problems that the invention seeks to solve) In recent years, there has been an urgent need for drastic improvements to transportation systems in order to eliminate rush hour traffic and chronic road congestion, especially in metropolitan areas. Due to the current situation, we have no choice but to make effective use of underground space for this development.

Tunnels are a means of utilizing underground space,
When attempting to construct a structure under a building's shaft, etc., the construction location has to be deep, and its cross section tends to be large.

When a tunnel is constructed using the shield method under such conditions of great depth and large cross-section, a large cross-sectional force acts on the segments that are the lining material. For example, Figure 8 shows the changes in the cross-sectional force acting on the segment due to earth pressure, water pressure, etc. when a tunnel is constructed under certain soil conditions.In the case of a large depth and a large cross-section, bending moment and axial force change. You can see that they are getting quite large. In addition, especially when the cross section is large, the influence of the jack thrust acting on the segment is large, and generally speaking, the thrust per jack is 6 for small and medium diameters.
0 to 150 tf, while the large diameter is 200 to 4 tf.
It is expected to be 00 tf.

When using existing segments for linings that are subject to such large cross-sectional forces, the following problems arise.

In steel segments, all of the large cross-sectional force is made of steel, so a considerable amount of steel is required and costs tend to be high. Furthermore, in order to prevent deformation of the tunnel cross section, it is necessary to ensure the required rigidity, which causes an increase in the amount of steel material.

When a reinforced concrete segment has a large cross-sectional force, it is necessary to increase the thickness of the segment to resist this force. Therefore, in order to secure a predetermined tunnel space, the amount of excavated soil increases, which increases construction costs.

In addition, the weight of the segments increases rapidly, resulting in poor workability and transportability, and when cracks occur, there is a risk of water leakage due to high water pressure at great depths.

Furthermore, since the bottom segment described in JP-A No. 61-286497 is made of steel to form a hexahedral sealed steel shell, the amount of steel is large and the manufacturing cost of the steel shell is also high. Furthermore, since non-shrinkable unreinforced concrete is poured under pressure, there are problems with the uniformity of the concrete parts and the reliability of the performance.

It is an object of the present invention to solve the above-mentioned problems with conventional segments and to provide a bottom segment that has high strength, high rigidity, and excellent economic efficiency.

[Means to solve the problem]

Hereinafter, an overview of the present invention will be explained using reference numerals in the drawings corresponding to the embodiments.

The bottom segment 1 of the present invention has steel plates 2 and 3 on the inner side of the tunnel and on the ground side, and has a structure in which both ends of the steel plates 2 and 3 in the tunnel circumferential direction are bent in opposite directions. Of course, this bending part is not limited to the case where a single steel plate is bent, but can also be formed by welding separate steel plates), and concrete 4 is poured between them. A dowel 9 is provided on the concrete 4 side of the steel plates 2, 3 so that the steel plate 2.3 and the concrete 4 behave in a composite manner in response to an external force, thereby integrating the steel plate 2.3 and the concrete 4. The bent portion of the steel plate 2.degree. 3 not only has the function of preventing the concrete 4 from slipping, but also constitutes a joint surface (in whole or in part) in the circumferential direction of the tunnel.

In order to improve the adhesion performance between the steel plates 2.3 and the concrete 4, it is possible to form protrusions 11 on the concrete 4 side of the steel plates 2, 3 in addition to the dowels 9, and also to form protrusions 11 on the side opposite to the concrete 4. By also forming the protrusion 12,
It is also possible to improve the integrity with the secondary lining of the tunnel interior and the backfilling material on the tunnel ground side.

[For production]

The synthetic segment l of the present invention configured as described above is
Since the m-handles 2 and 3 have a sandwich shape located at the outermost edge of the concrete 4, the steel plate part works effectively against tensile force (bending force), and the concrete part works effectively against compressive force, thereby improving the material properties of both. can be effectively demonstrated. In addition, since the concrete 4 is restrained by the steel plates 2 and 3, it has excellent strength and toughness. In addition, by using the dowel 9, it has a shear reinforcing effect on the concrete 4, and also prevents peeling of the steel plate 2.3, and has a structure in which the end of the steel plate 2.3 is bent toward the concrete 4 side. Therefore, the steel plate 2゜3 and the concrete 4 do not shift.

Furthermore, when the protrusions 11 are added to the steel plates 2 and 3, the rigidity of the steel plates 2 and 3 themselves and the adhesion performance to the concrete 4 are improved, and the effect of preventing peeling of the steel plate of the - layer and the effect of preventing slippage can be obtained. In addition, if the shape of the protrusions 11 is made into a diamond pattern or a lattice pattern, the influence of the directionality on the adhesion performance will be reduced (become
Peeling and displacement of the steel plate 2.3 from the concrete 4 caused by both the tunnel radial load due to earth pressure, water pressure, etc. and the tunnel axial load due to jack thrust etc. can be effectively prevented. In addition, since the protrusions 11 improve the crack dispersion performance of the concrete 4 (the width of each crack becomes smaller due to the occurrence of many cracks uniformly distributed in the concrete member), some cracks The behavior of the structure is no longer dominated by the extension and boshin, leading to improved strength.

Furthermore, by providing protrusions on both sides of the steel plate 2.3,
The rigidity of the steel plates 2 and 3 itself has been further improved, and the secondary lining,
In addition, when backfilling is performed, the tunnel structure can be integrated with the backfilling process, improving the strength of the entire tunnel structure.

In addition, since the composite segment 1 of this proposal has a steel plate 2.3 on the outer edge, a formwork for the core part is not required, and since the segment side surface is not made of a steel plate, the seal groove 10
It also has manufacturing advantages such as easy installation.

〔Example〕

Next, the illustrated embodiment will be described.

FIGS. 1 and 2 show an embodiment of the present invention, in which a composite segment 1 has a skin plate 2 on the inner side of the tunnel.
It has an inner steel plate 2 consisting of a and a joint plate 2b, and an outer steel plate 3 consisting of a tunnel earth side skin plate 3a and an end plate 3b, and bolt boxes 5, 6, grout injection holes 7, etc. are installed at predetermined positions of these steel plates 2, 3. In addition to forming
Four sections of concrete are formed sandwiched between steel plates 23.

The joint +ff12b at both ends of the steel plates 2 and 3 and the end plate 3b face each other and form part of the segment circumferential joint surface, and the joint plate 2b is provided with a bolt hole 8 that passes through the bolt box 5. ing.

Further, a large number of headed dowels 9 can be provided on the concrete 4 side surfaces of these steel plates 2 and 3 so as to transmit force at the interface with the concrete 4 and resist external forces together. be. Furthermore, in this embodiment, a seal groove 10 is provided on the side surface of the composite segment 1 when concrete 4 is poured.

This composite segment 1 is connected to the shield machine erector (
The tunnel is completed by assembling the parts (not shown) and tightening them with bolts. At that time, the seal groove 10 is filled with a sealing material and grouting is performed from the grout injection hole 7. , ground subsidence, and water leakage can be prevented.

FIG. 3 shows another embodiment of the present invention, in which a steel plate 2.
3 is a case where a steel plate with projections having projections 1 on the concrete 4 side is used. By using a steel plate with protrusions, an even better effect of preventing the steel plate from separating can be obtained, and the synthesis of the steel plate and concrete becomes more complete.

FIG. 4 shows still another embodiment of the present invention, in which a projection 12 is also provided on the opposite side of the above-mentioned steel plate with projections,
Since it can be integrated with the secondary lining material and backfilling material, the strength of the entire tunnel structure is improved.

Note that the shapes of the protrusions 11 and 12 shown in the examples are as follows:
From the viewpoint of reducing the directionality of adhesion strength, the rhombus shape shown in Figure 5 and the grid shape shown in Figure 6 are desirable, but if it increases adhesion to concrete, the vertical striped shape shown in Figure 7 is preferable. The shape is not limited. Furthermore, the cross-sectional shape of the protrusion and the shape of the main body of the dowel 9, which uses a headed stand in the above embodiment, may be variously modified without departing from the spirit of the present invention.

[Effects of the invention] ■ Sand inch structure in which steel plates are arranged symmetrically on the outer and inner sides of the segment ring! iii The plate portion efficiently responds to tensile force (bending force), and the concrete portion efficiently responds to compressive force.

■ The strength of the concrete part is increased by the restraint effect of the steel plate on the concrete and the shear reinforcement effect by the dowel.
In addition, toughness is improved. Furthermore, if a steel plate with projections is used, the steel plate itself is stiffened, thereby increasing the rigidity of the segment.

■ Both ends of the steel plate are bent toward the concrete, so there is no misalignment between the two parts, and the steel plate is anchored to the concrete with dowels, preventing buckling or peeling of the steel plate. can. Furthermore, if a steel plate with protrusions is used, the adhesion performance is improved and further buckling and peeling prevention effects can be obtained.

■ When protrusions are provided on both sides of the steel plate, the rigidity of the steel plate itself is further improved, and it can be integrated with the secondary lining material and backfill injection material, increasing the strength of the entire tunnel.

■ As a result of the above, the load-bearing capacity of the tunnel is greatly improved, and the thickness of the segments can be made thinner and the weight can be reduced, thereby improving constructability and transportability.

■ Also, since the segments can be made thinner, the amount of excavation required to secure a specified tunnel cross section can be reduced.
Construction costs are reduced.

■ On the other hand, focusing on the manufacturing cost of the segment body, the steel plate part doubles as the formwork when pouring concrete, and seal grooves can be easily added, so manufacturing costs can be reduced. Therefore, it is possible to form inter-segment joints that require strength relatively easily.

■ Furthermore, since the segment corners are made of steel, concrete
1. Corner chipping can be prevented, and even if the concrete cracks, water leakage can be prevented because the concrete is covered with a steel plate.

Taking all of the above performance into account, the segments of the present invention are extremely superior in terms of rigidity and strength compared to conventional segments, can be manufactured at low cost, and have reduced construction costs due to thinner segment walls. Total cost can be significantly reduced.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing one embodiment of the present invention, Fig. 2 is a sectional view of a steel plate portion, Fig. 3 is a sectional view of a steel plate portion in another embodiment, and Fig. 4 is a sectional view of a steel plate portion in another embodiment. 5 to 7 are internal views showing the protrusion shape of the steel plate, FIG. 8 is a diagram showing changes in cross-sectional force acting on the lining, FIG. 9 is a perspective view showing an overview of the shield tunnel, and FIG. FIG. 10 is a perspective view of a conventional steel segment, and FIG. 11 is a perspective view of a conventional reinforced concrete segment. 1... Bottom segment, 2... Inner steel plate, 2a...
・Skin plate, 2b...Joint plate, 3...Outside steel plate, 3a...Skin plate, 3b...End plate, 4...Concrete, 5.6...Bolt box,
7... Grout injection hole, 8... Bolt hole, 9...
Jiheru, 10...Seal) tIff, 11.12...
・Protuberance genealogy diagram Sho R - used instep - m hemi

Claims (3)

[Claims] (1) In a composite segment for tunnel lining made of steel and concrete, steel plates with dowels are used on two sides of the tunnel, one on the ground side and the other on the inner side, and both ends of the steel plates in the tunnel circumferential direction are A composite segment characterized in that a bent portion constituting a joint surface is provided, concrete is cast between the steel plates, and the dowel integrates the steel plates and the concrete sandwiched between the steel plates. (2) The composite segment according to claim 1, wherein the steel plate is a steel plate with protrusions formed on the surface in contact with the concrete. (3) The composite segment according to claim 1 or 2, wherein the steel plate has a protrusion formed on a surface opposite to the concrete.