JPS6354875B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for assembling a reinforcing cage for reinforcing tunnel wall lining material. This is used in the field of assembling reinforcing bars to reinforce the lining material in a ring shape in the shield excavation method, in which tunnel excavation is carried out while sequentially placing the lining material forming the tunnel wall.

[Prior art]

When constructing a tunnel wall on the inner surface of an excavated tunnel, the formwork that has been made in advance is assembled into a ring shape, and a lining material is placed between the formwork and the tail plate of the shield body, and after it hardens. There is a shield excavation method in which the formwork is removed and tunnel walls are formed while excavating. In such construction methods, as a method of reinforcing the cast lining material, a formwork for casting the lining material is assembled in advance into a ring shape inside the excavated tunnel, and steel fiber is placed around the outer periphery of the formwork ring. There is one that casts a very early strength cement mixed with it. In this case, the cast lining material is pressed in the machine axis direction with a pressure jack, which promotes densification and solidification of the lining material, and once the lining material is solidified, the lining material absorbs the digging reaction force of the shield jack. Tunnel excavation is being carried out during this period. Therefore, the lining material is reinforced with steel fibers, which are cast together with the lining material, making the work relatively simple, but there is the problem that it is not easy to ensure a high degree of reinforcement and uniformity. be.
Moreover, expensive ultra-high-strength cement is required as a lining material, leading to a rise in construction costs. Apart from this, there is a method of assembling reinforcing reinforcing bars into a ring shape prior to placing the lining material inside the tunnel. In this method, a large number of push rods are installed between the assembled reinforcing bars, and extend vertically in the machine axis direction, and a formwork made by dividing into rings is assembled around the inner periphery of the push rods. Then, when the lining material is cast around the outer periphery of the formwork ring, a tunnel wall with embedded reinforcing bars and push rods is formed.
It is now possible to excavate while taking the excavation reaction force with the push rod. This does not require early hardening of the lining material and allows the use of inexpensive early-strength cement or ordinary cement.
In order to prepare for pouring the lining material, a series of heavy work is required, including assembling reinforcing bars in a ring shape, installing push rods, and assembling the formwork in a ring shape, which requires a great deal of time and hard labor. Ru. In addition, separate special jigs are required for each task, complicating assembly and disassembly operations within narrow tunnels, and there is a strong demand for improvement.

[Purpose of the invention]

The present invention was made in order to solve the various problems mentioned above, and its purpose is to enable reinforcing bars for reinforcing lining materials to be assembled in a short time without using special jigs. To provide a method for assembling a reinforcing bar cage for reinforcing a tunnel wall lining material, which can shorten the construction period and reduce construction costs by forming a formwork ring at the same time.

[Structure of the invention]

Hereinafter, the features of the present invention will be explained based on the drawings. In the shield excavation method in which the tunnel is excavated while sequentially placing the lining material 20 forming the tunnel wall, a plurality of reinforcing bars 1a, 1b, 1c are arranged vertically and horizontally. A split reinforcing bar cage 1 assembled in an arc shape,
This is a method of assembling a reinforcing bar cage for reinforcing a tunnel wall lining material, in which the reinforcing bar cage for reinforcing a tunnel wall lining material is integrated in advance with the corresponding divided formworks 2a and 2b, and the formwork 2 is assembled together with the reinforcing bar cage 1 on the inner surface of the tunnel by an erector 11.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Figure 1 shows an example of a reinforcing bar cage 1 that is manufactured by dividing it in advance to reinforce the lining material.
A reinforcing bar 1b connecting these in the axial direction of the tunnel and a reinforcing bar 1c connecting them in the radial direction of the tunnel are assembled by welding or the like. For example, five reinforcing bar baskets 1 form one ring, and each of the reinforcing bar cages 1 is secured in the circumferential direction as will be described later. FIG. 2 shows one formwork ring 2A consisting of formworks 2 for pouring lining material, and as shown in the figure, for example, three formworks 2a of the same shape and two formworks 2b of the same shape are shown. It consists of a total of five formworks made of iron plates: and one key formwork 2c. These are each manufactured in advance and assembled into a ring shape within the tunnel, and projections 3 are provided as necessary. As shown in FIG. 3, the protrusion 3 of the formwork 2 is provided with an appropriate number (one in the figure) of clampers 4 to integrate the reinforcing bar basket 1, and are used to clamp the arc-shaped reinforcing bars. 1a or axial reinforcing bars 1b. Reference numeral 5 in FIG. 4 is an erector device for assembling the formwork 2 integrated with the reinforcing bar cage 1 into a ring shape. It is installed on the outer periphery of a cylindrical ring 7 extending in the direction so as to be rotatable and slidable back and forth. An outer cylindrical body 8 is rotatably fitted onto the cylindrical ring 7, and a drum 9 is slidably fitted onto the outer cylindrical body 8. This drum 9 has a plurality of cylinders 1 that expand and contract in the radial direction of the shield body 6.
0 is attached, and an erector 11 is provided at its tip, which is formed with a pressing surface 11a that chucks the formwork 2 and holds the position of the formwork 2 integrated with it when assembling the reinforcing bar cage 1 into a ring shape. ing. The drum 9 has a motor (not shown) fixed to the cylindrical ring 7 and a cylinder 12 that moves the drum 9 in the axial direction of the cylindrical ring 7 mounted on the outer cylinder 8 in the axial direction.

According to the above configuration, the reinforcing bar cage 1 can be assembled together with the formwork 2 in the following manner.

As shown in FIG. 5a, the shield main body 6 excavates one ring width by extending the shield jack 13 while taking the excavation reaction force by the existing formwork ring 2A. After it is completed shield jack 1
3, a space 14 of one ring width is created at the inner peripheral portion of the tail plate 6a. During excavation, a roller conveyor (not shown) provided in the upper part of the shield body 6 transports the removed formwork 2 from the rear part where the lining material has solidified, and a new reinforcing bar cage 1 is constructed as shown in FIG. As shown in FIG. When the erector device 5 moves near the support 16 fixed to the ring girder 15 as shown in FIG. 5b, the erector 11 moves the formwork 2 integrated with the reinforcing bar cage 1 as shown in FIG. Check and incorporate it into the space 14. During this assembly, the cylinder 10 (see FIG. 4) of the erector device 5 is stopped after it has expanded by a predetermined amount, so that the reinforcing bar cage 1 is placed at a predetermined radial position. At this time, the formwork 2 is joined to the previously assembled formwork 2, and the erector 1
1 functions as a jig to hold the reinforcing bar cage 1,
Working lid 1 provided on formwork 2 as shown in Fig. 6
7 is removed, and the peripheral ends 1A of adjacent reinforcing bar cages 1 are secured with iron wires 18, welding, or the like. Since the reinforcing bar cages 1 are only secured at the center of the formwork 2 with clampers 4 such as bolts, the worker can easily grasp the peripheral ends 1A of two adjacent reinforcing bar cages 1 and align them. can. When the reinforcing bar cage 1 and the formwork 2 are assembled into a ring shape as shown in Fig. 4, the shield jack 13 extends to the front end surface of the formwork ring 2B that has just been assembled, as shown in Fig. 5d. As a result, the press ring 19 is brought into contact. Then, a lining material 20 such as very early strength cement or ordinary cement is cast through a lining material casting hole (not shown) provided in the formwork 2 . During this time, the formwork ring 2B is maintained by the erector 11, and when the casting is completed, the shield jack 13 is further extended and the formwork ring 2B takes up the digging reaction force, while the cutter attached to the shield body 6 Excavation is resumed by rotating the disk 21. In addition, since the reinforcing bar cage 1 described above only needs to be finally assembled into a ring shape, the number of divisions can be arbitrarily selected. of course,
The same applies to the formwork 2. Also, if the formwork 2 and reinforcing bar cage 1 are always assembled together, work efficiency will be improved, but for example, key formwork 2c (see Figure 2)
In some cases, it may be easier to assemble the reinforcing bar cage 1 if it is assembled alone. Therefore, when assembling the reinforcing bar cage 1, its dimensions, shape, and assembly procedure are selected in consideration of workability.

In the above-mentioned process of shield excavation,
Since the reinforcing bar cage 1 and the formwork 2 are simultaneously assembled into a ring shape by the erector device 5, the assembly work can be speeded up. In addition, since the excavation reaction force can be transmitted to the solidified lining material 20 at the rear by the assembled formwork ring 2B, there is no need to wait for the lining material to solidify, and there is no need to use expensive ultra-early strong cement as the lining material. Nor. Furthermore, since the rebar cage and formwork can be integrated while the shield body is being excavated, the time required for integration to form the tunnel wall will not be extended. do not have.

〔Effect of the invention〕

As can be seen from the detailed description of the above-mentioned embodiments, in the shield excavation method in which lining material is poured into the excavated tunnel wall, split reinforcing bar cages are assembled in a circular arc shape by arranging multiple reinforcing bars vertically and horizontally. Since the reinforcing bar basket for reinforcing the lining material is assembled in advance with the corresponding divided formwork and assembled by the erector, the reinforcing bar cage for reinforcing the lining material is assembled at the same time as the formwork, and the working time is extremely shortened. Further, since the formwork held by the erector functions as a jig for assembling the reinforcing bar cage into a ring shape, assembly accuracy is improved and special jigs are not required. Therefore, there is no need to assemble or remove jigs, and a work space is secured within the narrow shield body, thereby improving work efficiency.

[Brief explanation of drawings]

Figure 1 is a perspective view of a split reinforcing bar basket, Figure 2 is a diagram of a ring-shaped assembly of formwork with different circumferential shapes,
Figure 3 is a front view of the formwork with integrated reinforcing bar cages.
Fig. 4 is a cross-sectional view of a reinforcing bar cage and formwork assembled in a ring shape and an erector device for assembling them; Figs. 5 a to d are explanatory diagrams of the work procedure for assembling the reinforcing bar cage and formwork and shield excavation;
FIG. 6 is a diagram showing a state in which adjacent reinforcing bar cages are secured and a state in which lining material is placed. 1...Reinforcement cage, 1a, 1b, 1c...Reinforcement bar,
2, 2a, 2b, 2c... formwork, 11... erecta, 20... lining material.

Claims (1)

[Scope of Claims] 1. In the shield excavation method in which the tunnel is excavated while sequentially placing lining materials to form the tunnel wall, a split reinforcing bar cage assembled in an arc shape with multiple reinforcing bars arranged vertically and horizontally is used in this method. A method for assembling a reinforcing bar cage for reinforcing a tunnel wall lining material, which comprises integrating the reinforcing bar cage into a corresponding split formwork in advance, and assembling the formwork together with the reinforcing bar cage on the inner surface of the tunnel using an erector.