JPH0821182A - Concentricity holding mechanism of parent-child shield machine and concentricity holding method - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a parent-child shield excavator capable of smoothly starting the child shield while ensuring the concentricity of the parent shield and the child shield. [Composition] Having a rotatable parent cutter head 5 at the front,
Further, in the parent shield 1 propelled into the ground by the parent shield jack 3, a rotatable child cutter head 12 is provided in the front portion, and a child shield 20 having an outer diameter smaller than the inner diameter of the parent shield 1 is provided. A concentricity holding means is slidably interposed in the circumferential gap 6 between the parent shield 1 and the child shield 2 to maintain the concentricity of the parent shield 1 and the child shield 2, and at the same time, the child shield 2 described above. The child shield jack 10 provided in the parent shield 1 allows the child shield 2 to start freely from the inside of the parent shield 1. When the concentricity holding means ensures the concentricity of the parent shield 1 and the child shield 2, The shield 2 can be smoothly started.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parent-child shield excavator capable of continuously excavating tunnels having different diameters by a parent shield and a child shield.

[0002]

2. Description of the Related Art Conventionally, as a shield machine having a parent shield and a child shield, one disclosed in, for example, JP-A-3-132597 is known. The tunnel excavator disclosed in the above publication is a shield excavator capable of starting a small-diameter shield (child shield) from inside a large-diameter shield (parent shield) to change the tunnel diameter during excavation.

In such a parent-child shield excavator, if the inner diameter of the parent shield and the outer diameter of the child shield are not accurately finished, the concentricity will be deviated, and the child shield will be caught when the child shield starts. The smooth start of the vehicle is hindered. As an improvement, it is not preferable to finish the inner diameter of the parent shield and the outer diameter of the child shield by machining to increase the concentricity because the manufacturing cost increases.

If there is a gap between the parent shield and the child shield, the child shield falls due to the weight of the child shield, so that the centers of the parent shield and the child shield are deviated from each other, and concentricity cannot be secured. There is also a problem that the seal function is different depending on the location, such that the crushed amount of the seal provided between the parts is larger than the upper part due to the self-weight of the child shield.

Further, in the case of a method in which the parent shield cutter head is supported by the parent shield and only the rotational torque is transmitted from the child shield cutter head to the parent shield cutter head, the parent shield and child shield cutter heads are eccentric to each other. If so, an unreasonable force acts on the torque transmission portion, which is not preferable. The present invention has been made to improve such conventional problems, and an object of the present invention is to provide a shield machine capable of smoothly starting the child shield while ensuring the concentricity of the parent shield and the child shield. It is a thing.

[0006]

In order to achieve the above object, the present invention has a rotatable child cutter head in the front part in a parent shield propelled into the ground by a parent shield jack, and A child shield having an outer diameter smaller than the inner diameter of the parent shield is provided, and a concentricity holding structure is slidably interposed in the radial gap between the parent shield and the child shield to increase the concentricity of the parent shield and the child shield. The child shield is held, and the child shield can be started from the inside of the parent shield by the child shield jack provided on the child shield. Another object of the present invention is to provide a concentricity holding method for maintaining concentricity by filling a backing material around the inner circumference of the parent shield skin plate and the outer circumference of the child shield skin plate before starting the child shield.

Further, the concentricity holding structure is formed of a liner plate, and the liner plate is provided over the entire circumference of the child shield or is divided into a plurality of pieces in the circumferential direction. Further, the concentricity holding structure is formed by a large diameter portion provided in the front portion of the child shield.

[0008]

With the above structure, a small-diameter tunnel can be continuously dug into a large-diameter tunnel while maintaining the concentricity of the parent shield and the child shield, and a gap formed by the concentric holding structure between the parent shield and the child shield. Therefore, when the child shield starts, there is no chance of getting caught between them. Further, since the concentricity holding structure makes the crush amount of the seal substantially equal, there is no malfunction of the sealing function.

Further, since the liner plate is divided into a plurality of parts in the circumferential direction, the contact friction between the parent shield and the child shield is reduced, so that the child shield can be smoothly propelled with less propulsive force and the ground penetration. The time resistance can also be reduced. Further, even if the concentricity holding structure comes off by filling the backing material, the concentricity can be maintained until the child shield comes off the parent shield.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings shown in FIGS. FIG. 8 is a cross-sectional view of a state where the parent shield and the child shield are integrally advanced, and FIG. 1 is a cross-sectional view of the child shield starting after the excavation by the parent shield is completed and the child shield is ready to start. Two
Is a cross-sectional view taken along the line AA of FIG. 1, FIG. 3 is an explanatory view of a state where the child shield starts from the parent shield, and FIG. 4 is an explanatory diagram of a state where the child shield is separated from the parent shield.

In these figures, 1 is a parent shield and 2 is a child shield concentrically housed in the parent shield 1.
The parent shield 1 has a cylindrical skin plate 1a, and a plurality of parent shield jacks 3 are provided inside the skin plate 1a at intervals in the circumferential direction. By the shield jack 3, the already assembled parent segment 4 receives the reaction force and the parent shield 1 is propelled into the ground.

On the other hand, the child shield 2 has a tubular skin plate 2a having a diameter slightly smaller than the inner diameter of the parent shield 1, and is formed on the inner peripheral surface 1c of the parent shield 1 and the outer peripheral surface of the skin plate 2a of the child shield 2. A gap 6 is formed between them.
A liner plate 7 serving as a concentricity holding structure is interposed in the gap 6, and the liner plate 7 ensures the concentricity of the parent shield 1 and the child shield 2.

The liner plate 7 is divided into, for example, four parts in the circumferential direction as shown in FIG. 2, and is fixed to the outer peripheral surface of the skin plate 2a of the child shield 2 at equal intervals.

A taper portion 7a having a diameter gradually decreasing toward the end is formed at the tip of each liner plate 7,
The tapered portion 7a reduces the penetration resistance when penetrating into the natural ground, and the liner plate 7
A seal 8 is provided on the rear side of. The seal 8 has an annular shape and has a purpose of preventing water from entering the shield from the outside of the shield. Further, as the second concentricity holding means, a method is used in which the backing material is filled around the inner circumference of the parent shield skin plate and the outer circumference of the child shield skin plate. The concentricity holding means by the first liner holds the front side of the child shield concentrically, but has no effect on the rear side of the child shield. The backing material not only concentrically holds the stroke of the child shield out of the parent shield, but also serves as a support wall for the child shield segment.

Inside the skin plate 2a of the child shield 2, a plurality of child shield jacks 10 are provided in the circumferential direction, and these child shield jacks 10 assemble the inside of the parent segment 4 to the child segment 4a.
To receive the reaction force to propel the child shield 2 into the ground, and a child cutter head 12 is provided at the front portion of the child shield 2. The child cutter head 12 has an outer diameter substantially equal to the outer diameter of the child shield 2, and is rotationally driven by a child cutter head motor (not shown). After being taken into the chamber 1b, it is conveyed to the rear by an unillustrated earth discharging device as in the case of the parent shield 1. In FIG. 1, reference numeral 13 denotes a parent tail seal provided at the rear portion of the parent shield 1, and 14 denotes a child tail seal provided at the rear portion of the child shield 2.

To explain the operation, when excavating a large-diameter tunnel, as shown in FIG. 8, the parent shield 1 and the child shield 2 are simultaneously grounded with the child shield 2 housed in the parent shield 1. Then, the parent cutter head 5 and the child cutter head 12 excavate the face while excavating the face. At this time, the concentricity of the parent shield 1 and the child shield 2 is ensured by the liner plate 7 interposed between the parent shield 1 and the child shield 2.

After excavating the large diameter tunnel, when the small diameter tunnel is to be excavated subsequently to the large diameter tunnel, a reaction force receiver 4b is attached to the front end of the parent segment 4 assembled along the inner wall of the large diameter tunnel. Then, the opening in the tunnel direction between the inner circumference of the parent shield skin plate 1a and the child shield skin plate 2a is closed, and then the child segment 4a is assembled. In this state, backfilling of mortar or the like between the parent shield 1 and the child shield 2 The material 9 is injected to form a support wall for the child shield segment and also serves as a concentricity holding means for the child shield. The rear end of the child shield jack 10 is the child segment 4
When the child segment 4a is brought into contact with the child segment 4a, the child shield jack 10 propels the child shield 2 as shown in FIG. 3, and the child cutter head 12 starts excavation of the small diameter tunnel. At this time, since the outer peripheral surface of the liner plate 7 fixed to the outer peripheral surface of the child shield 2 is fitted into the inner peripheral surface 1c of the parent shield 1, the child shield 2 can be smoothly started.

Further, since the gap 6 is previously formed between the inner peripheral surface 1c of the parent shield 1 and the outer peripheral surface of the skin plate 2a of the child shield 2, there is no possibility of catching between the two. Since the taper 7a is previously formed at the front end of the liner plate 7 projecting from the outer peripheral surface of the skin plate 2a of the child shield 2, the penetration resistance when penetrating into the natural ground is small, which may hinder the promotion of the child shield 2. It will not come.

As shown in FIG. 4, the liner plate 7 projecting from the outer peripheral surface of the child shield 2 is disengaged from the parent shield 1 as the child shield 2 is dug, but in this state, the front portion of the child shield 2 is removed. Has penetrated a considerable amount of ground and the weight of the child shield 2 is supported by the ground, so that the center of the child shield 2 can be continued from the center of the parent shield 1 and the excavation can be continued. When parent shield 1
Even if the center of the child shield 2 is slightly displaced from the center of,
Since the gap 6 is provided in advance between the parent shield 1 and the child shield 2, it does not hinder the excavation. Further, since the filled backing material concentrically supports the rear portion of the child shield, the concentricity can be reliably maintained until the child shield comes out of the parent shield.

When the child shield 2 is disengaged from the parent shield 1 as described above, the child segment 4a is assembled as the child shield 2 is dug, and the child tunnel is further dug to dig a small-diameter tunnel. It is possible to excavate a small diameter tunnel in succession to the diameter tunnel.

In the above embodiment, the liner plate 7 interposed between the parent shield 1 and the child shield 2 is divided into a plurality of pieces in the circumferential direction, but as shown in FIGS. You may attach integrally over. In this case, the contact resistance with the parent shield 1 is slightly increased as compared with the case of division, but the concentricity is further improved.

Further, in FIG. 7, instead of providing the liner plate 7 on the outer periphery of the child shield 2, a large diameter portion 2b having an outer diameter substantially equal to the inner diameter of the inner peripheral surface 1c of the parent shield 1 is provided on the front portion of the child shield 2. The large diameter portion 2b is formed to have the function of the liner plate 7. In this case as well, the tapered portion 7a is formed in the front portion of the large diameter portion 2b in order to reduce the ground penetration resistance. .

Further, in the above embodiment, the large diameter portion 2b is provided in the front portion on the child shield 2 side instead of the liner plate 7.
The same function can be obtained even if the liner plate 7 is provided on the parent shield 1 side.
Does not become the penetration resistance when the child shield 2 is dug.

[0024]

As described in detail above, according to the present invention, the outer diameter of the child shield housed in the parent shield is made smaller than the inner diameter of the parent shield to form a gap therebetween, and at the same time, in this gap, Since the concentricity holding means that holds the concentricity of the parent shield and the child shield is provided, after the large diameter tunnel is excavated by the parent and child shield, the child shield is started from the parent shield, so that the small diameter tunnel continues to the large diameter tunnel. Can be drilled.

When the child shield is started from the parent shield, the concentricity of the parent shield and the child shield is held by the concentricity holding means, so that the concentricity of the child shield is not disturbed by the weight of the child shield. Since a gap is formed in advance between the child shields, the child shield can be smoothly started without being caught between the two when the child shield is started.

On the other hand, by forming the concentricity holding means by a liner plate or by forming a large diameter portion in the front portion on the child shield side, the range of machine finishing can be greatly reduced, and thus the manufacturing cost can be greatly reduced. At the same time, by forming the taper portion at the front end of the liner plate, it is possible to reduce the penetration resistance of the natural ground, so that the propulsive force of the child shield can be reduced.

The liner plate may be of an integral structure, but if it is divided into a plurality of pieces in the circumferential direction, the contact friction between the parent shield and the child shield is reduced, so that the child shield can be started with a smaller propulsive force. Since the resistance when the earth penetrates is also reduced, the propulsive force of the child shield can be reduced. If the outer diameter of the front part of the child shield is increased or the inner diameter of the front part of the parent shield is decreased to form concentricity holding means, the liner plate can be omitted and the concentricity can be reduced. By filling the backing material between the rear part of the parent shield and the rear part of the holding means, not only the concentric maintaining stroke becomes longer, but also
It also serves as a support wall for the child shield segment.

[Brief description of drawings]

FIG. 1 is a sectional view of a parent-child shield excavator according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an explanatory view showing a state where the child shield starts from the parent shield of the parent-child shield excavator according to the embodiment of the present invention.

FIG. 4 is an explanatory view showing a state in which the child shield is separated from the parent shield of the parent-child shield excavator according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram of a parent-child shield excavator according to another embodiment of the present invention.

6 is a cross-sectional view taken along the line BB of FIG.

FIG. 7 is an explanatory diagram of a parent-child shield excavator according to another embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a state in which the parent shield of the parent-child shield excavator according to the embodiment of the present invention has completed the excavation.

[Explanation of symbols]

 1 Parent shield 1c Inner peripheral surface of parent shield 2 Child shield 2a Skin plate 2b Large diameter part 3 Parent shield jack 4 Parent segment 4a Child segment 4b Reaction force receiving 5 Parent cutter head 6 Gap 7 Liner plate 7a Tapered portion 8 Seal 9 Back Packing material 10 Child shield jack 12 Child cutter head

Front page continuation (71) Applicant 000001236 Komatsu Ltd. 2-3-6 Akasaka, Minato-ku, Tokyo (72) Inventor Masanori Ikeda 930-24 Miho-cho, Midori-ku, Yokohama-shi, Kanagawa Forest Hills 1-304 ( 72) Inventor Yoshio Abe 2-22-7 Kurihara Chuo, Zama City, Kanagawa Prefecture (72) Inventor Sachi Mochizuki 1-1-103 Senwaka-cho, Kanagawa-ku, Yokohama City Kanagawa Prefecture (72) Izumi Nishizawa Ueno, Hirakata City, Osaka Prefecture 3-1-1 Komatsu Mfg. Co., Ltd. Osaka Plant (72) Inventor Norio Mitani 3-1-1 Ueno, Hirakata, Osaka Prefecture Komatsu Mfg. Co., Ltd. Osaka Plant

Claims (6)

[Claims] 1. A parent shield, which is propelled into the ground by a parent shield jack, has a rotatable child cutter head in a front portion and has a child shield having an outer diameter smaller than the inner diameter of the parent shield, A parent-child shield excavator having a concentricity holding structure provided in a radial gap between the parent shield and the child shield. 2. The parent-child shield excavator according to claim 1, wherein the concentricity holding structure is formed of a liner plate, and the liner plate is fixed to at least one of the inner peripheral surface of the parent shield and the outer peripheral surface of the child shield. . 3. The parent-child shield excavator according to claim 2, wherein the liner plate is divided into a plurality of pieces in the circumferential direction. 4. The parent-child shield excavator according to claim 1, wherein the concentricity holding structure is formed by providing a large-diameter portion on the front portion of the child shield or a protrusion on the inner peripheral surface of the front portion of the parent shield. 5. The parent-child shield excavator according to claim 1, wherein a seal is provided behind the concentricity holding structure. 6. In the parent-child shield excavator, before starting the child shield, a backing material is filled in the periphery between the inner peripheral side of the parent shield skin plate and the outer peripheral side of the child shield skin plate, and the child shield segment A concentricity holding method characterized in that the inner shield is supported and the child shield holds the concentricity until it comes out of the parent shield.