JP2508966Y2 - Tail seal for cast-in-place lining shield method - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a tail seal for a cast-in-place lining shield construction method in which a shield machine is dug by pressure for placing concrete.

[Prior Art] The above-mentioned cast-in-place lining shield method is, for example,
As described in Japanese Patent Application No. 62-330145, which is related to the applicant's application, it is formed by the end form of the skin plate, between the inner form built in the ring, and the surrounding ground. While pouring concrete by pouring it into the voids with a high pouring pressure with a high-pressure pump, resist the pouring pressure against the surrounding ground of the cast concrete and the existing concrete lining generated at that time. This is a construction method characterized in that the pressure is taken as a reaction force and the pressure is transmitted to the excavator through the end form formed in the shield tail portion to propel the excavator. In this construction method, when the concrete is poured, the shield tail is sealed to prevent the concrete from leaking inside the shield.

[Problems to be Solved by the Invention] However, in the above-mentioned known tail seal, when concrete is placed at a high placing pressure, the concrete leaks from the gap between the skin plate and the ground, which causes the placing pressure to rise. There was a problem that the excavation of the excavator was significantly reduced.

The object of the present invention is to mount a wire seal on a skin plate, so that it is possible to place concrete at a high placing pressure without causing leakage of concrete, and therefore, the excavation of the excavator is improved. The purpose of the present invention is to provide a tail seal for the cast-in-place lining shield method constructed.

[Means for solving the problem]

In order to achieve the above-mentioned object, the tail seal for cast-in-place lining shield method according to the present invention is provided with pipes at the rear end of the skin plate at equal intervals, and relatively long wires are inserted in the pipe in the natural direction. It is to be inserted by directing to, and to be compressed.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.

FIG. 1 is a cross-sectional view showing a known shield machine main body A in the excavated state. The excavator main body A is composed of a shield head portion 1 and a shield tail portion 7 each having a cutter on the face side corresponding to the structure of a normal shield, for example, a mechanical shield. In the shield tail portion 7, which is an extension of the shield skin portion 1, a tail seal is inserted between the end formwork 10 for concrete pouring and the inner formwork 5, and the surrounding natural ground 11 and The air space between the inner formwork 5 and the inside of the shield machine main body A is sealed.

The end formwork 10 for pouring concrete is provided with an opening for passing a conduit 3 for pumping concrete for pouring. Therefore, the conduit 3 is open in the space between the surrounding ground 11 and the inner form 5 in the end form 10 for placing concrete.

In the internal air space C of the shield machine main body A, a high-pressure concrete pump 8 is provided which is placed on an abutment 9, and from this high-pressure concrete pump 8, the concrete pressure-feeding conduit 3 for lining concrete is placed into the concrete pouring. It ends with an opening formed in the end formwork 10 for installation.

As can be seen from FIG. 1, the excavation is performed by, for example, a full-section excavator, and the concrete 4 is placed in the air space 4 ′ formed in the inner formwork 5 and the surrounding ground 11 as the excavation progresses. The lining 6 is formed. At this time, this concrete is pressed at a high pressure from the high-pressure concrete pump 8 through the concrete-lined concrete pressure-feeding conduit 3 for placing the lining concrete. And work to promote. Further, due to this pressure, the concrete itself receives a pressurizing action to form a dense lining 6 in the air space 4 '.

As shown in FIG. 2, in the publicly known excavator B,
In the structure of the tail seal provided in the tail portion, the concrete 4 is placed in the air space 4 ′ formed between the inner formwork 5 and the ground 11 through the lining concrete pressure-feeding conduit 3 from the high-pressure pump. In order to prevent the concrete 4 from penetrating into the gap 16 between the skin plate 7 and the natural ground 11 due to the driving pressure at the time of setting, for example, synthetic rubber or
A tail seal 13 formed in a plate shape with a main material such as urethane rubber is mounted on the circumference of the end portion of the skin plate 7, whereby the end portion is sealed.

Further, FIG. 3 shows a tail seal structure D according to the present invention.
FIG. 4 is a perspective view of a tail seal structure D according to the present invention. The tail seal structure D is composed of a skin plate 12, a wire 13 and a pipe 14, and a pipe 14 is provided at an end of the ring-shaped skin plate 12.
Are provided at equal intervals, and a wire 13, which will be described later, is fixed in the pipe 14 by pressure. As can be seen in FIG. 3, in this case, the wire 13 is provided like a blind on the entire circumference of the skin plate 12 and is formed as a sealing layer (see also FIG. 4). In this case, the angle of the pipe is bent upward at an angle of, for example, 45 ° with respect to the central axis of the pipe 14 so as to properly contact the ground 13 with the wire 13.

Next, the size of the wire 13 used for the tail seal is, for example, an outer diameter of 20 mm-JIS No. 14 equivalent and a length of 150 to 200 mm. Either Z or S twists may be used instead of this wire, but rank twists are used more advantageously than ordinary twisted wires for the reasons described below. That is, the feature of this rank is that the contact surface between the wire and the outside is less damaged by friction and is highly flexible.

Next, regarding the relationship between the length and diameter of the wire rope,
Depending on the outer diameter of the shield machine, the corresponding ground, and the size of the curve for the excavation route, the wire rope length should be 7 to 10 times the rope diameter.
That is, the wire rope diameter is 20 mm and the wire rope length is
It is 150 to 200 mm.

In order to theoretically design the tail seal structure D of the present invention, a model experimental device for a shield machine shown in FIG.
It is an example of a model experiment. The structure of this model experimental device is as follows: a skin plate 30 having an outer diameter of 1600 mm, an outer cylinder 31 having an inner diameter of 1660 mm that assumes a natural ground, and an outer diameter of 1000 that assumes an inner mold.
It comprises an inner cylinder 32 of mm, a side plate 33, a cylinder rod 34, a hydraulic cylinder 35, a concrete pipe 36, a concrete pump 37 and a wire seal 40 according to the present invention.
The skin plate 30 is fixed to the left end portion 38, and the hydraulic cylinder 35 is fixed to the right end portion 39, and the end portions of the outer cylinder 31 and the inner cylinder 32 are welded to the side plate 33, respectively. A wire seal 40 according to the present invention is circumferentially attached to the end of the skin plate 30.

Next, the operation of this model experiment device will be described. The concrete 43 is poured into the air space 41 by the concrete pump 37 via the concrete pipe 36 and is further filled. By filling this concrete, the pouring pressure becomes high,
This pressure moves in the direction of arrow 42 with respect to the side plate 33 (the above-mentioned outer cylinder 31 and inner cylinder 32 move), whereby the hydraulic cylinder 35 is shown in FIG. 6 via the cylinder rod 34. Adjust the concrete pouring pressure. Therefore, the concrete lining is formed in the air space while automatically maintaining the concrete pressure within a certain range.

Regarding the effect of the wire seal 40 of this experimental device and the behavior of concrete, when the concrete comes into contact with the wire seal at the initial stage of placement and is further filled, the mortar component in the concrete leaks out from the gap of the wire seal.

However, the aggregate with a diameter of 20 mm ((crushed stone) could not pass through the maximum clearance 12 mm of the wire seal immediately, and it became a filter because it was clogged tightly and closed, sand → fine particles 20
Block in that order. Initially, a very small amount of mortar leaks, but finally only the water dehydrated under pressure comes to be squeezed out. These are not the amounts that particularly hinder the shield excavation work. The experimental values in this experimental apparatus are as follows.

Amount of concrete placed: 1.6m ³ Dewatering leakage: 1.0
%, And the outflow of small-diameter gravel mortar: 0.17%. Therefore, it was confirmed that the durability and the followability of the wire seal by this experimental device are sufficiently practical for high-pressure concrete pouring.

[Action]

A pipe 14 is provided on the circumference of the skin plate 12 shown in FIG. 3 and FIG. 4, and a wire 13 inserted into this pipe is in contact with the surface of the natural ground 11, By pouring high-pressure concrete from the concrete conduit 3 and filling the air space 4 ′, the concrete is brought into close contact with the gap between the wires 13. This allows the structure to act as a durable and compliant seal layer.

〔effect〕

In the tail seal for the cast-in-place lining shield method of the present invention, pipes are provided at the rear end of the skin plate at equal intervals, and relatively long wires are inserted into the pipe so as to be oriented in the natural direction, Since it is compressed, it has excellent wear resistance against the ground of the ground by utilizing the rigidity and flexibility of the wire, especially for the shield machine where the ground is uneven and the direction is controlled. The followability is always obtained, and even if the concrete is placed with a high placing pressure, the leakage of the concrete between the ground and the tail seal is extremely small.

[Brief description of drawings]

FIG. 1 is a sectional view of a shield machine main body, FIG. 2 is a sectional view of a conventional tail seal structure, FIG. 3 is a sectional view of a tail seal structure according to the present invention, and FIG. 4 is according to the present invention of FIG. FIG. 5 is a perspective view of the tail seal structure, FIG. 5 is a cross-sectional view of the model experiment device of the sealing machine, and FIG. 6 is a characteristic graph of concrete pressure and concrete filling time. Reference numeral in the figure 3 ... Concrete conduit 5 ... Inner form, 7 ... Skin plate 11 ... Ground 13 ... Wire 14 ... Pipe 16 ... Gap, A ... Shield machine D ... Tail seal structure

Claims (1)

(57) [Scope of utility model registration request] 1. A tail seal for a cast-in-place lining shield method in which a shield machine is used to excavate by a concrete placing pressure, wherein pipes (14) are provided at the rear end of a skin plate (12) at equal intervals. A tail seal for the cast-in-place lining shield method, characterized in that a relatively long wire (13) is inserted into the pipe (14) so as to be oriented toward the natural ground (11) and is pressed.