JPH066877B2 - Overcast shield construction method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a construction method for constructing a reinforced concrete lining structure by a cast-in-place shield construction method.

"Problems to be solved by conventional techniques and inventions" In the conventional cast-in-place shield construction method, the reinforced concrete lining method assembles the rebar and the inner formwork in the tail after completion of excavation, and uses the tail plate as the outer formwork After placing concrete between the frames, press the uncured concrete with a high pressure by a press ring that also works as a gable formwork that moves forward and backward with a jack, so that the shield machine is propelled while transmitting thrust. Are known.

However, in the conventional construction method, since the rebar, the formwork and the press ring are assembled on-site, a lot of labor and time are required for the process, and since there is no continuity of the rebar between the lining spans, the integrity between spans is improved. It had a shortcoming, and it was not possible to perform excavation and concrete pouring at the same time.

"Means for Solving the Problems" In order to solve the above-mentioned conventional problems, the present invention has a partition steel plate having a reinforcing bar on the rear surface and a joint bar on the front surface in the ring direction in the inner circumference of the rear end of the shield body. While assembling in a series, arrange the waterproof sheet from the rear surface of the partition plate to the upper rear of the rebar, install the lining formwork behind the inner peripheral portion of the partition steel plate, and insert the partition plate from the injection hole of the lining formwork. By propelling the shield body while filling the rear void with concrete, at the same time as assembling the partition steel plate that functions as a gable formwork, the reinforcing bars can be reinforced and the process can be simplified. The attached joint and reinforcing bars integrate the front and rear lining concrete to enable stress transmission in the span direction, while preventing the concrete from leaking with a waterproof sheet. It proposes a construction method that enables pouring of concrete at the same time as excavation without involving the earth and sand.

"Example" Hereinafter, an example of the present invention shown in the drawings will be described.
As shown in FIG. 1, a plurality of partition steel plates 2 are assembled in the inner circumference of the rear end of the shield body 1 in a ring shape, and a lining form 3 is assembled in a ring shape from the inner circumference of the partition steel plate to the rear thereof.

As shown in FIGS. 1 and 2, the partition steel plate 2 is formed by, for example, forming a T-shaped steel material having a flange on the inner peripheral side into an arc shape,
Reinforcing bar baskets 4 are attached to the rear surface, and joint materials such as lap bars 5 or shear connectors 6 are attached to the front surface as shown in FIGS. Each partition steel plate 2 is configured to be connected in the ring direction by fastening the joint plates 7 provided at both ends with bolts 8.

In addition, as shown in FIG. 5, a water stop plate 9 that also serves as a water stop after concrete pouring and a joint material is provided in a projecting manner on the front and rear surfaces of the partition steel plate 2, if necessary.

A waterproof sheet 10 is attached to the rear surface of the partition steel plate 2, and the waterproof sheet 10 is arranged with some slack so as to cover the rear reinforcing bar basket 4.

After the partition plate 2 and the lining mold 3 are installed as described above, concrete 12 is filled from the injection hole 11 provided in the mold 3, and the shield body 1 is propelled with the shield body 1 accordingly.
3 promotes while taking a reaction force to the formwork 3.

By the propulsion of the shield body 1, the rear part of the partition steel plate 2 gradually comes out of the shield body 1 and is released to the natural side, but by keeping the filling pressure of the concrete 12 continuously filled constant, The concrete 12 is placed in close contact with the natural ground while pushing out the waterproof sheet 10 and leaving no tail void.

In this case, since the waterproof sheet 10 covers the filled concrete 12 and cuts the edge from the earth and sand of the natural ground, the quality of the concrete can always be kept uniform without involving the earth and sand.

Further, by balancing the filling pressure of concrete, it becomes possible to place concrete at the same time as promoting the shield machine.

After the concrete 12 having a predetermined span is cast in this manner, the propulsion of the shield body 1 is stopped and the same steps are continuously repeated to successively construct a lining of a reinforced concrete structure. Then, the lining concrete 12 of each span is continuously integrated by the reinforcing bar cage 4 of the front and rear partition steel plates 2 and 2 and the lap bar 5 or the shear connector 6,
Further, the water blocking plate 9 is continuously integrated by the adhesive force with the concrete 12, so that the stress transmission in the span direction and the shear reinforcement are possible.

[Advantages of the Invention] As described above, according to the present invention, at the inner circumference of the rear end of the shield body, the reinforcing steel plates are attached to the rear surface, and the partition steel plates having the joint material attached to the front surface are assembled in series in the ring direction, and A waterproof sheet is arranged from the rear side to the upper rear side of the reinforcing bar, a lining form is installed behind the inner peripheral portion of the partition steel plate, and concrete is filled in the rear space of the partition plate from the injection hole of the lining form frame. However, since the shield body is promoted, 1) the reinforcing bars are laid out at the same time as the assembly of the partition steel plate that functions as a gable form, and the process before concrete filling can be simplified.

2) Joint material and rebars attached to the front and rear of the partition steel plate integrates the front and rear lining concrete, enabling stress transmission in the span direction.

3) With the waterproof sheet placed behind the partition plate, it is possible to place concrete without entanglement of the earth and sand while preventing concrete from leaking and to ensure the quality of concrete.

4) Concrete is poured while propelling the shield body, so that the tail void can be immediately filled with concrete, and concrete can be poured at the same time as excavation while preventing the collapse of the ground.

[Brief description of drawings]

1 is a vertical sectional side view showing a construction state according to the present invention, FIG. 2 is a perspective view showing a part of an assembled state of a partition steel plate according to the present invention, FIG. 3 is a rear view thereof, FIGS. 4 and 5 The figure is a vertical cross-sectional view showing another embodiment of the partition steel plate. 1 ... Shield body, 2 ... Partition steel plate, 3 ... Lining formwork, 4 ... Reinforcing bar cage, 5 ... Lap bar, 6 ... Shear connector, 7 ... Joint plate, 8 ... Bolt, 9 ...・ Water stop plate, 10 ・ ・ Waterproof sheet, 11 ・ ・ Injection hole, 12 ・ ・ Concrete, 13 ・ ・ Propulsion jack.

Claims (1)

[Claims] 1. A shield steel plate having a reinforcing bar on the rear surface and a joint material attached to the front surface is assembled in series in the ring direction on the inner circumference of the rear end portion of the shield body, and waterproof is provided from the rear surface of the partition plate to the upper rear of the reinforcing bar. A sheet is arranged, a lining form is installed behind the inner peripheral portion of the partition steel plate, and the shield body is propelled while filling concrete into the rear space of the partition plate from the injection hole of the lining form. Characteristic place overcast shield construction method.