JPH01131797A - Cast-in-place concrete lining construction method - Google Patents

Abstract

PURPOSE: To insure continuity of reinforcement by laying a reinforcement in the direction of a tunnel axis through a coupler for reinforcement mounted on the extreme end of a concrete press jack, and overlapping with the axial reinforcement of existing concrete by a required length. CONSTITUTION: Through holes are provided in a row in the circumferential direction on a press ring plate 2 on the extreme end of a concrete press jack 1, and a coupler 4 for reinforcement joint threadedly fitted to reinforcement 3 in the direction of a tunnel axis is fitted thereto, and the reinforcement 3 is fixed to the plate 2. The plate 2 is moved to an annular space formed among an inner form B, a tail plate C, and existing concrete A forming a concrete placing space. The space is filled with concrete D, the jack 1 is operated to press in until the reinforcement 3 of the plate 2 and the reinforcement 3' projected from the front face of the existing concrete A are overlapped by required length, and the concrete D is pressurized and filled. Consequently, continuity of reinforcement can be ensured.

Description

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

(Conventional technology) The cast-in-place concrete lining 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 is a method of constructing a primary lining without creating tail voids by filling concrete under pressure between the front surface and the existing concrete lining.

(Problems to be solved by the invention) In the cast-in-place concrete lining method,
In the process of sequentially pressurizing and filling the lining concrete rings per construction unit width, it is necessary to make the reinforcing bars in the tunnel axis direction structurally continuous. There is no construction method to easily ensure the
There was a problem in that the reinforcement required a lot of effort and the construction period was extended. - (Means for Solving the Problems) The present invention was proposed to solve these problems, and includes an inner formwork assembled in a tunnel hole excavated by a shield excavator and the excavator. Concrete is placed in the annular space formed between the tail plate of the shield excavator and the front surface of the existing lining concrete, and is removably attached to the press ring plate at the tip of the concrete press jack installed on the shield excavator. Attach the tunnel axial reinforcing bars via the installed reinforcing bar joint couplers, and insert the same 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. While pressurizing the poured concrete, the shield excavator is moved forward, 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 develops the specified strength. After that, the press ring plate is retreated to the face side with only the coupler remaining in the concrete, and the next lining concrete 1 is placed on the coupler.
This relates to a cast-in-place concrete lining construction method characterized by fixing the axial reinforcing bars of the tunnel.

(Function) In the present invention, in order to pressurize and fill the lining concrete cast into the annular space, a reinforcing bar joint coupler is removably attached to a press ring plate at the tip of the press jack in the tunnel axial direction. Attach the reinforcing bars, insert the press ring plate with the reinforcing bars protruding toward the existing concrete lining through the concrete press jack into the annular space, and fill the space with concrete under pressure. The tunnel axial reinforcing bars on the press 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 remove the exposed ground where the tail plate has moved forward and the inner formwork. 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. At the very least, move the press ring plate to the face side via the concrete press jack, and connect the tunnel axial reinforcing bars of the next lining concrete part to the reinforcing bar joint coupler remaining in the concrete part, and then proceed in the same manner as above. By repeating the above process, a cast-in-place concrete lining is constructed so that lap joints are formed between the tunnel axial reinforcing bars in 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, and (2) is a press ring plate at the tip of the same jack (1), which is used to drill tunnels into through holes (2a) arranged circumferentially. The reinforcing bar joint coupler (4) screwed onto the threaded end of the axial reinforcing bar (3) is fitted, and the nut (5) is screwed onto the outer threaded part of the coupler (4) to tighten it. (3
) is fixed to the press ring plate (2).

At this time, the reinforcing steel (3) is the existing concrete lining (A).
The tunnel axial reinforcement (3') protrudes from the front of the tunnel and slightly circumferentially! 1III position. Therefore, two through holes (2a) are arranged adjacent to each other in the circumferential direction for each reinforcing bar attachment position, and these through holes (z&) 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),
Then, the press ring plate (2) is moved into the annular space formed between the front of the existing concrete lining (A) and the tail plate (C>) of the shield excavator, and concrete lining is poured. Form a construction space (see Figure 1) and place highly fluid concrete (D) in the inner formwork (B) in the same space.
(See Figure 2) through the concrete injection pipe (E) attached to the concrete press jack (1).
) to move the press ring plate (2) into the annular space so that the tunnel axial reinforcing bars (3) attached to the press ring plate (2) protrude from the front side of the existing lining concrete (A). The concrete (
The shield excavator is moved forward while pressurizing D), and the accompanying movement of the tail plate (C) places the concrete (D) between the ground exposed in the tunnel hole and the inner formwork (B). Fill under pressure. (See Figure 3) In the figure (
F) is a circumferential reinforcing bar.

When the concrete (D>) reaches a predetermined strength, the nut (5) of the press ring plate (2) is removed, leaving only the reinforcing bar joint coupler (4) in the concrete (D). (2) to the face side, attach the tunnel axial reinforcing bars for the next concrete lining section to the coupler (4), and then repeat the same process as above to attach the tunnel axial reinforcement for the adjacent concrete lining section. A tunnel is constructed with a cast-in-place concrete lining with lap joints formed between axial reinforcing bars.

(Effects of the Invention) According to the present invention, as described above, 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 are provided. Using the press ring plate at the tip of the concrete press jack for pressurizing the concrete placed in the formed annular space, the tunnel axial reinforcing bars are attached via the reinforcing bar joint coupler that is removably attached to the plate. ,
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 them, 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 mole child jack (2)...
Press ring plate (3) (3')...Tunnel axial reinforcing bar (4)...
Coupler for reinforcing bar joint (5)...Nut (A>...Existing lining concrete (B)...Inner formwork (C)...Tail plate (
D)...Concrete

Claims (1)

[Claims] Concrete is poured into an annular space formed between 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, and the shield excavation is completed. Tunnel axial reinforcing bars are attached to the press ring plate at the tip of the concrete press jack mounted on the machine via a reinforcing bar joint coupler that is detachably attached, and the press ring plate is used to attach the reinforcing bars to the existing lining. 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 concrete part, and connecting the ground mass exposed on the inner surface of the tunnel hole with the inner formwork. During this period, the concrete is pressurized and filled, and after the concrete has developed a predetermined strength, only the coupler remains in the concrete, and the press ring plate is retreated to the face side, and the next lining is placed on the coupler. A cast-in-place concrete lining construction method that is characterized by fixing the axial reinforcing bars of the tunnel in the concrete section.