JPH0447280Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention is a concrete lining used in the cast-in-place lining shield construction method to prevent water leakage from the joint between the skin plate of a shield excavator and the concrete lining. This invention relates to a press pressure holding device.

<Prior art> The cast-in-place lining shield construction method is a method in which, at the same time as a shield excavator excavates, a cast-in-place lining shield is installed between the inner circumferential surface of a skin plate that constitutes the outer shell of the shield excavator and the formwork assembled inside the skin plate. This is a construction method that forms a concrete lining while high-pressure pressing the concrete that has been placed.Compared to conventional construction methods, there is no need for a backfill injection process, there is no ground collapse in the tail void area, and high strength is achieved by high-pressure pressing. A uniform lining structure can be obtained.

In this construction method, the shield tunneling machine moves forward and the concrete is pressed under high pressure by a jack installed on the inner circumference of the skin plate, and the thrust is received by a press ring placed at the tip of the poured concrete. There is.

Therefore, the skin plate advances due to the reaction force of the jack, and the poured concrete is compressed via the press ring, but after that, the jack is reduced to remove the press pressure, and then the concrete is compressed through the press ring. The formwork and press ring are re-set in the front, and the concrete pouring, shield tunneling machine moving forward, and high-pressure pressing work are repeated.

《Problems to be solved by the invention》 However, after one stage of advancement of the shield excavator and high-pressure pressing work has been completed, the press ring has been removed and the press pressure has been removed. The length of the joint between the outer periphery and the inner peripheral surface of the skin plate becomes shorter as the skin plate moves forward, and since the press pressure has been removed, there is a slight difference in the joint between the skin plate and the concrete lining. Gaps are likely to occur. If the ground is permeable and the groundwater level is high, there was a risk that groundwater could flow into the shield pit through these gaps, causing unexpected accidents and work stagnation.

This idea was created in view of the above problems, and it maintains the press pressure introduced into the concrete even after the press ring is removed, thereby ensuring water tightness between the skin plate and the concrete lining. An object of the present invention is to provide a concrete lining press pressure holding device that can improve safety and workability when assembling forms and press rings.

<Means for solving the problem> In order to achieve the above object, the concrete lining press pressure holding device of this invention is installed between the skin plate of the shield excavator and the formwork assembled inside it. Press the concrete
A device for holding the press pressure introduced into the concrete, comprising a bracket rotatably attached to the front edge of the formwork, and a rotationally fixed device provided at the rotating end of the bracket. The present invention is characterized in that it includes a pressing plate that faces the concrete casting tip surface at a position and a biasing means that presses and biases the pressing plate against the concrete pouring tip surface.

<<Example>> Hereinafter, an example of this invention will be described in detail using the drawings.

Figures 1a, b, and c are sectional views showing the construction order of the cast-in-place lining shield construction method to which this invention is applied.

In the figure, a shield tunneling machine 1 is provided with a plurality of jacks 3 extending rearward on the inner periphery of a cylindrical skin plate 2.

Also, on the inner circumference of the rear part of the skin plate 2, a formwork 4 having a length corresponding to the stroke length of the jack 3 is provided.
are assembled into a cylindrical shape, and a press ring 5 is located between the skin plate 2 and the formwork 4, facing the jack 3.

In this cast-in-place lining shield construction method, as shown in Figure a, concrete C is placed between the most advanced formwork 4 and the skin plate 2 through a concrete pouring pipe 6.

After pouring the concrete C, the face is excavated by the shield excavator 1, and the excavated soil is discharged into the shield excavator 1 and the existing shield pit 7 behind it through the conveyors 8 and 9 while the jack 3 is extended. Then, as shown in FIG.
Move forward by the stroke of .

At the same time, the concrete C is pressed under high pressure by the jack 3 through the press ring 5, filling the tail void on the rear side of the skin plate 2 and forming a high-strength and uniform concrete lining C'.

Next, as shown in FIG. By assembling 4 and arranging the press ring 5 on the front side, preparation for pouring concrete C for lining in the next step is completed.

By repeating steps a to c in the figure, shield excavation is performed in sequence.

Here, when the jack 3 is fully extended as shown in Fig. 1b, the joint length between the poured concrete C and the skin plate 2 is extremely short, so the press ring 5 is removed and the If this disappears, a gap will be created in this joint, and there is a risk that groundwater will leak into the shield excavator 1 through this gap.

Therefore, in this embodiment, as shown in FIGS. 2 and 3, a plurality of press pressure holding devices 20 are provided at appropriate intervals in the circumferential direction on the front edge of the formwork 4.
By maintaining the press pressure introduced into the concrete C, the skin plate 2 and the concrete C, that is, the concrete lining
Ensures watertightness between C′.

That is, the press pressure holding device 20 of this embodiment
A substantially U-shaped bracket 22 is rotatably supported via a pivot pin 21 on the inner periphery of the front end of the formwork 4 placed at the most advanced position of concrete pouring, and a bracket 22 is provided at the pivot end of the bracket 22. The integrated hydraulic jack part 23 and the plunger 2 of the hydraulic jack part 23
Pressing plate 2 integrally joined to the tip of 4
5, and a hydraulic jack 27 for rotating the bracket 22.

The rear end of the hydraulic jack 27 is swingably supported via a pivot pin 28 on a bearing 4a provided on the inner circumference of the formwork 4, and the plunger 27
9 is connected to the bracket 22 via a connecting pin 30.

In the steps a and b of FIG. 1, as shown in FIG.
As a result of the shrinkage of the holding device 20, the holding device 20 is held at a position where it does not protrude to the outer circumferential side of the formwork 4 into which concrete is poured, and does not interfere with the pressing operation performed by the press ring 5 and the jack 3.

In addition, in the step of FIG. 1c, after removing the press ring 5, by operating the hydraulic jack 27, the bracket 22 is rotated to the upright state as shown in FIG. The rotational position is restricted by abutting the inner peripheral surface 22' against the front end surface of the mold 4, and the hydraulic jack 27 fixes the mold at that position. At this position, the pressing plate 25 faces the tip surface of the concrete C to be placed.

Next, by operating the hydraulic jack part 23, the plunger 24 protrudes, and the pressing plate 25
comes into contact with the pouring tip surface of the concrete C, and sufficiently pressurizes this surface to maintain the introduced press pressure.

Therefore, the joint surface between the concrete C and the skin plate 2 is brought into close contact with each other due to the pressurization.
This means that sufficient water-tightness can be ensured in this part.

Note that this holding device 20 has pivot pins 21 and 28.
Since it can be easily removed by pulling out, by making each formwork 4 have a tip structure suitable for this installation, it can be moved after the concrete C has completely hardened and reset to the pouring tip position for the next process. .

In addition, the formwork 4 receives a reaction force in the forward direction due to pressurization, but since each formwork 4 is connected over a considerable distance behind the shield excavator 1, the influence of this reaction force is almost ignored. can.

<<Effects of the invention>> As explained in detail in the examples above, according to this invention, even after the press ring is removed, the press pressure against the concrete lining can be maintained constant, so the assembly work of the formwork and press ring can be reduced. Sufficient water-stopping properties can be ensured when carrying out such operations, and safety and workability can be easily improved.

[Brief explanation of drawings]

FIGS. 1a, b, and c are sectional views showing the construction order of the cast-in-place lining shield method to which this invention is applied, and FIGS. 2 and 3 are partial sectional views showing the press pressure holding device of this invention. DESCRIPTION OF SYMBOLS 1... Shield excavator, 2... Skin plate, 3... Jacket, 4... Formwork, 5... Press ring, 20... Press pressure holding device, 21... Pivot pin, 22... Bracket, 23... Hydraulic jack part (biasing means), 25... Pressing plate, C
...Concrete, C'...Concrete lining.

Claims (1)

[Scope of utility model registration request] A device for pressing concrete placed between a skin plate of a shield excavator and a formwork assembled inside the same, and for maintaining the pressing pressure introduced into the concrete, the front end of the formwork being pressed. a bracket rotatably attached to the edge; a pressing plate provided at the rotating end of the bracket and facing the concrete pouring tip surface at the rotationally fixed position of the bracket; and the pressing plate is connected to the concrete pouring tip. 1. A concrete lining press pressure holding device comprising: urging means for applying pressure to a surface.