JPH0464400B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] On-site lining of a shield tunnel that can sufficiently pressurize unhardened concrete without moving the reinforcing bars even if the lining is brought into close contact with the ground. This is an invention related to construction methods.

[Conventional technology]

In the conventional direct shield construction method, the reinforcing bars in the longitudinal direction of the tunnel use a lap joint method, so the lap joints become an obstacle when pressurizing concrete that has not yet hardened. Therefore, through holes for reinforcing bars are made in the press ring or pressure plate.
It is necessary to assemble the reinforcing bars through these holes, which not only complicates the assembly of the reinforcing bars, but also makes it difficult to maintain pressure between the through holes and the reinforcing bars.

Furthermore, in the method of pressurizing unhardened concrete and bringing the lining into close contact with the ground, there is a risk that the reinforcing bars may move, and the weak concrete poured one step before the process has low strength, so the assembled reinforcing bars may move. had a drawback that had a negative impact on existing concrete.

[Problem that the invention seeks to solve]

This invention attempts to solve the problems of the complexity of assembling reinforcing bars and the adverse effects of movement of reinforcing bars on the weak concrete lining that was placed one step before the process.

[Means to solve the problem]

The pressure ring with the fitting hole for the inner and outer circumferential reinforcing steel members attached to the press jack in the shield machine tail is pulled back in the shield excavation direction, and the inner and outer circumferential reinforcing steel members in the longitudinal direction of the tunnel and the existing inner and outer circumference are pulled back in the shield excavation direction. After connecting the reinforcing bar fixing steel members and placing the circumferential reinforcing bars on the inner and outer circumferential reinforcing bar fixing steel members, frame the inner formwork in front of the existing inner formwork, and extend the press jack to attach the circumferential reinforcing bar fixing steel members. The tip of the shield is fitted into the fitting hole of the pressure ring to airtightly close the space between the shield machine tail and the inner form, and then the lining is formed with the pressure ring, the machine tail, the inner form and the existing lining material. After injecting the lining material into the material injection space, slide the shield machine tail in the direction of tunnel excavation, pressurize the pressure ring with a press jack, and after the concrete hardens, shield the pressure ring attached to the press jack in the shield machine tail. The problem was solved by pulling back in the direction of excavation and repeating the work in sequence.

[Effect]

The pressure ring with the fitting hole of the inner and outer circumferential reinforcing steel attached to the press jack in the shield machine tail is pulled back in the shield excavation direction by a length longer than that required to form the lining material injection space, and the inside of the tunnel in the longitudinal direction is The outer circumferential reinforcing steel material and the existing inner and outer circumferential reinforcing steel material are fixed with mechanical joints or welded joints are used to connect the outer circumferential reinforcing steel material and the existing inner and outer circumferential reinforcing steel material. After installing and fixing the circumferential reinforcing bars in the grooves and the multiple semicircular grooves provided on the outside of the inner circumferential reinforcing bar fixing steel, attach the stopper steel near the front end of the inner and outer circumferential reinforcing bars to the existing inner mold. After framing the inner formwork at the front of the frame and fixing the inner circumferential reinforcing steel material to the inner formwork with fasteners, extend the press jack and fit the tip of the circumferential reinforcing steel material with the pressure ring. After fitting into the hole to airtightly close the space between the shield machine tail and the inner formwork, inject the lining material into the lining material injection space formed by the pressure ring, machine tail, inner formwork, and existing lining material. After that, slide the shield machine tail in the direction of tunnel excavation, pressurize the pressure ring with a press jack to harden the concrete, and then move the pressure ring attached to the press jack in the shield machine tail to form a lining material injection space. The shield is pulled back by the same length in the direction of shield excavation to prepare for the next work.A fitting hole is made in the pressure ring, an elastic filler is loaded into the fitting hole, and the tip of the steel material is covered with concrete. When pressurizing the concrete, it is inserted into the fitting hole and the concrete is pressurized without any problem.

By fixing the longitudinal steel joint with a mechanical joint, the number of fitting holes for the pressure ring can be reduced.

Circumferential reinforcing bars are placed and fixed in the steel grooves to prevent concrete from moving when pressurized.

By connecting the steel members near the pressure ring, the entire assembled reinforcing bar can be prevented from moving. Furthermore, by fixing the inner formwork and the steel material with fasteners, it is possible to prevent the reinforcing bars in the weak-grade concrete from moving one step before.

〔Example〕

Press jack 2 inside shield machine tail 1
A pressurizing ring 6 having fitting holes 5 for inner and outer circumferential reinforcing steel members 3 (hereinafter referred to as inner steel members) and 4 (hereinafter referred to as outer steel members) attached thereto is attached to a length that forms a lining material injection space 7. 1 or more (long enough to assemble reinforcing bars, etc.) back in the direction of shield excavation, and fix the inner steel members 3 and outer steel members 4 in the longitudinal direction of the tunnel to the existing inner steel members 3 and outer steel members 4 with mechanical joints 8. , circumferential reinforcing bars 11 are arranged and fixed in a plurality of semicircular grooves 9 provided on the inside of the outer steel material 4 and a plurality of semicircular grooves 10 provided on the outside of the inner steel material 3, and the front ends of the inner and outer steel materials 3, 4 are fixed. Attach the stopper steel material 12 nearby and attach the existing inner formwork 1.
The inner formwork 14 is fixed to the front part of the inner formwork 1.
4, the inner steel material 3 is fixed to the stopper 15.

Thereafter, the press jack 2 is extended, and the tips of the inner and outer steel members 3 and 4 are fitted into the fitting hole 5 of the pressure ring 6, thereby airtightly closing the space between the shield machine tail 1 and the inner formwork 14.

An elastic filler 16 is loaded in the fitting hole 5 to protect the tips of the inner and outer steel members 3 and 4 and to prevent concrete from clogging the fitting hole.

After pouring a lining material 18 such as concrete into the lining material injection space 7 formed by the pressure ring 6, the shield machine tail 1, the inner formwork 14, and the existing lining material 17, the shield machine tail 1 is moved in the direction of tunnel excavation. (in the direction of the arrow x) and press the pressure ring 6.
After the concrete hardens by pressing the lining material 18 with the press jack 2, the press jack 2 is retracted and the pressure ring 6 is pulled back in the shield excavation direction by a length longer than that required to form the lining material injection space, completing one step.

A tunnel is formed by repeating this process sequentially. Reference numeral 19 denotes a mounting plate for the press jack 2, which is provided inside the machine tail 1. A plurality of lining material injection pipes 20 are provided.

〔Effect of the invention〕

The structure of the pressure ring, which has a special inner and outer steel material for reinforcing the tunnel in the axial direction and a fitting hole for inserting it, greatly improves reinforcing bar assembly efficiency, and the pressure ring has a through-hole. This reduces concrete runoff, improves the construction environment, and improves the quality of the lining as it prevents reinforcing bars from moving.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of the tunnel, Figure 2 is a, b,
C and D show construction procedure diagrams.

Claims (1)

[Claims] 1 Pull back the pressure ring with the fitting hole of the inner and outer circumferential reinforcing steel members attached to the press jack in the shield machine tail in the shield excavation direction, and tighten the inner and outer circumferential reinforcing steel members in the longitudinal direction of the tunnel and the existing inner and outer circles. After connecting the circumferential reinforcing steel members and placing the circumferential reinforcing bars on the inner and outer circumferential reinforcing steel members, frame the inner formwork in front of the existing inner formwork and extend the press jacks to fix the circumferential reinforcing bars. After fitting the tip of the steel material into the fitting hole of the pressure ring to airtightly close the space between the shield machine tail and the inner formwork, the cover formed by the pressure ring, machine tail, inner formwork and existing lining material is removed. After injecting the lining material into the material injection space, slide the shield machine tail in the direction of tunnel excavation,
A shield tunnel on-site lining construction method characterized by applying pressure to a pressure ring with a press jack, and after the concrete hardens, pulling back the pressure ring attached to the press jack in the tail of the shield machine in the direction of shield excavation, and repeating the work in sequence. .