JPH0514080B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a cast-in-place concrete lining method.

(Prior art) The cast-in-place concrete lining construction method involves arranging reinforcing bars for the lining within the shield tail of a tunnel hole excavated by a shield excavator, and assembling the inner formwork. This method constructs a primary lining without creating tail voids by filling concrete under pressure between the tail and the front of the existing lining concrete.

(Problems to be Solved by the Invention) In the cast-in-place concrete lining construction method, in the process of sequentially pressurizing and filling concrete rings per construction unit width, it is difficult to structurally connect reinforcing bars in the axial direction of the tunnel. Although it is necessary,
Conventionally, there was no method to easily ensure the structural continuity of reinforcing bars in the concrete lining, and the problem was that reinforcing bars required a great deal of effort, prolonging the construction period.

(Means for Solving the Problems) The present invention has been proposed to solve these problems, and includes an inner formwork assembled in a tunnel hole excavated by a shield excavator and the excavation machine. Concrete is placed in the annular space formed between the machine's tail plate and the front of the existing lining concrete, and can be freely attached to and detached from the press ring plate at the tip of the concrete press jack installed on the shield excavator. Attach the tunnel axial reinforcing bars through the reinforcing bar joint couplers attached to the lining, and press the press ring plate until the required amount of reinforcing bars overlap with the tunnel axial reinforcing bars protruding from the front of the existing concrete lining part. The shield excavator is moved forward while pressurizing the inserted concrete, and the concrete is pressurized and filled between the ground mass exposed on the inner surface of the tunnel hole and the inner formwork, and the concrete has a specified strength. After development, the press ring plate is retreated toward the face side with only the coupler remaining in the concrete, and the tunnel axial reinforcing bars of the next lining concrete part are fixed to the coupler. This relates to the concrete lining method.

(Function) In the present invention, in order to pressurize and fill the lining concrete cast into the annular space, the tunnel axial reinforcing steel is inserted through a reinforcing bar joint coupler that is detachably attached to the press ring plate at the tip of the press jack. A press ring plate with the reinforcing bars protruding toward the existing concrete lining is inserted into the annular space via a concrete press jack, and the concrete in the space is filled with pressure, and the press The tunnel axial reinforcing bars on the ring plate side and the existing lining concrete side are overlapped by a predetermined length, and at the same time, the shield excavator is advanced to connect the exposed ground where the tail plate has moved forward with the inner formwork. Concrete is densely filled in between so as not to cause tail voids, and after the concrete has developed a predetermined strength, the coupler for the reinforcing bar joint is separated from the press ring plate and only the coupler remains in the concrete. Then, the press ring plate is moved to the face side via the concrete press jack, and the tunnel axial reinforcing bars in the next lining concrete part are connected to the reinforcing bar joint coupler remaining in the concrete part, and then the same process as above is carried out. The cast-in-place concrete lining is constructed by repeating the process so that lap joints are formed between the reinforcing bars in the tunnel axis direction of adjacent concrete lining sections.

(Example) The present invention will be described below with reference to the illustrated embodiments.

1 is a concrete press jack mounted on a shield excavator, 2 is a press ring plate at the tip of the same jack 1, and has through holes 2 arranged in rows in the circumferential direction.
A reinforcing bar joint coupler 4 screwed onto the threaded end portion of the tunnel axial reinforcing bar 3 is fitted onto a, and a nut 5 is screwed and tightened onto the outer threaded part of the coupler 4 to attach the reinforcing bar 3 to the press ring plate. Fixed at 2.

At this time, the reinforcing bar 3 is the existing lining concrete A.
It is arranged so as to be slightly inconsistent in the circumferential direction with the tunnel axial reinforcing bar 3' protruding from the front surface of the tunnel. For this reason, two through holes 2a are arranged adjacent to each other in the circumferential direction for each reinforcing bar attachment position, and these through holes 2a groups are arranged in two rows, inside and outside. (See Figure 5) Then, the inner formwork B is assembled in the tunnel hole excavated by the shield excavator, and the inner formwork B and the front surface of the existing lining concrete A, as well as the shield excavation The press ring plate 2 is moved into the annular space formed between it and the tail plate C of the machine to form a lining concrete placement space (see Figure 1), and highly fluid concrete D is placed in the same space. is filled through the concrete injection pipe E attached to the inner formwork B (see Fig. 2), and the concrete press jack 1 is operated to insert the press ring plate 2 into the annular space. 2
The tunnel axial reinforcing bars 3 attached to the lining concrete A are press-fitted until they overlap with the tunnel axial reinforcing bars 3 protruding from the front surface of the existing lining concrete A by a required length l as shown in Fig. 4, and the concrete D is pressurized. While moving the shield excavator forward, the accompanying movement of the tail plate C causes the concrete D to be placed between the ground exposed in the tunnel hole and the inner formwork B.
Fill with pressure. (See Fig. 3) F in the figure is a circumferential reinforcing bar.

When the concrete D reaches a predetermined strength, the nut 5 of the press ring plate 2 is removed,
Only the coupler 4 for the reinforcing bar joint is left in the concrete D, and the press ring plate 2 is moved to the face side, and the tunnel axial reinforcing bars of the next lining concrete part are attached to the coupler 4, and the same process as described above is repeated. In this method, a tunnel is constructed with a cast-in-place concrete lining in which lap joints are formed between tunnel axial reinforcing bars of adjacent concrete lining sections.

(Effects of the Invention) As described above, according to the present invention, the inner formwork assembled in the tunnel hole excavated by the shield excavator, the tail plate of the excavator, and the front surface of the existing lining concrete Using a press ring plate at the tip of a concrete press jack for pressurizing the concrete poured in the annular space formed between the holes, the tunnel axial reinforcing bars are connected via a coupler for reinforcing bar joints that is detachably attached to the plate. Install the
When press-fitting the press ring plate into the annular space to pressurize the poured concrete in the same space, the tunnel axial reinforcing bars are connected to the tunnel axial reinforcing bars protruding from the front surface of the existing lining concrete to a required length. By overlapping, a lap joint is formed between the two reinforcing bars, ensuring continuity of the reinforcing bars in cast-in-place lining concrete, and making it possible to construct cast-in-place lining concrete with high structural reliability.

Furthermore, since the reinforcing bar joint coupler is removably attached to the press ring plate, when the concrete in the annular space develops the required strength, it can be unfixed to the press ring plate and left in the concrete. Therefore, using this reinforcing bar joint coupler, the tunnel axial reinforcing bars of the next concrete lining section can be attached.

[Brief explanation of the drawing]

Figures 1 to 3 are longitudinal sectional side views showing the steps of an embodiment of the cast-in-place concrete lining method according to the present invention, and Figure 4 is an enlarged view showing the lap joint of opposing tunnel axial reinforcing bars in Figure 3. A vertical side view and FIG. 5 are front views showing a state before tunnel axial reinforcing bars are attached to the press ring plate. 1... Concrete press jack, 2... Press ring plate, 3, 3'... Tunnel axial reinforcement,
4... Coupler for reinforcing bar joint, 5... Nut, A...
...Existing lining concrete, B...Inner formwork, C...
...Tail plate, D...Concrete.

Claims (1)

[Claims] 1. Concrete is poured into an annular space formed between the inner formwork assembled in the tunnel hole excavated by a shield excavator, the tail plate of the excavator, and the front surface of the existing lining concrete, The tunnel axial reinforcing bars are attached to the press ring plate at the tip of the concrete press jack mounted on the shield excavator via a coupler for reinforcing bar joints that is detachably attached to the press ring plate, and the press ring plate is attached to the press ring plate at the tip of the concrete press jack. The shield excavator is moved forward while pressing the poured concrete by inserting it until the required amount overlaps with the tunnel axial reinforcing bars protruding from the front surface of the existing concrete lining, and excavating the exposed ground on the inner surface of the tunnel hole and the above. After the concrete is pressurized and filled between the inner formwork and the concrete has developed a predetermined strength, the press ring plate is retreated to the face side with only the coupler remaining in the concrete, and the coupler is replaced with the next one. A cast-in-place concrete lining construction method characterized by fixing reinforcing bars in the axial direction of the tunnel in the concrete lining section.