JP2934383B2 - Parent-child shield excavator and method of maintaining concentricity - Google Patents

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 means of a parent shield and a child shield, and a concentricity between a parent shield and a child shield in the parent-child shield excavator. The present invention relates to a method of maintaining concentricity.

[0002]

2. Description of the Related Art Conventionally, a shield excavator having a parent shield and a child shield, for example, one disclosed in Japanese Patent Application Laid-Open No. 3-132597 is known. The tunnel machine described in the above publication is a shield machine capable of starting a small-diameter shield (child shield) from within a large-diameter shield (parent shield) in order to change the tunnel diameter during excavation.

[0003]

In the case of 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 is deviated and the child shield is caught at the time of starting. And the smooth start of the child shield 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 concentric accuracy because the manufacturing cost increases.

If there is a gap between the parent shield and the child shield, the child shield is lowered by the weight of the child shield, so that the center of the parent shield and the child shield are deviated and concentricity cannot be secured. There is also a problem that the sealing function differs depending on the location, for example, the lower part is larger than the upper part due to the crushing amount of the seal provided between them due to the weight of the child shield.

Further, in the case where the cutter head of the parent shield is supported by the parent shield and only the rotational torque is transmitted from the cutter head of the child shield to the cutter head of the parent shield, the cutter heads of the parent and child shields are eccentric. If it is, an excessive force acts on the torque transmission unit, which is not preferable. The present invention has been made in order to improve such a conventional problem, and provides a shield excavator and a method of maintaining concentricity in which the child shield can be started smoothly while the concentricity of the parent shield and the child shield is secured. It is intended to do so.

[0006]

In order to achieve the above object, a parent-child shield excavator according to a first aspect of the present invention includes a parent shield jack which is propelled into the ground by a parent shield jack. Has a free child cutter head,
A parent-child shield excavator comprising: a child shield having an outer diameter smaller than an inner diameter of the parent shield; and a concentricity holding structure provided in a radial gap between the parent shield and the child shield. The holding structure is formed of a liner plate, and the liner plate is integrally fixed to one of the inner peripheral surface of the parent shield and the outer peripheral surface of the child shield.

In the parent-child shield excavator according to the first invention, after excavating a large-diameter tunnel by integrating the parent shield and the child shield, the child shield is started from the parent shield to continuously connect to the large-diameter tunnel. A small tunnel is excavated. When starting the child shield, the concentricity of the parent shield and the child shield is maintained by the liner plate, so there is no concern that the concentricity will be deviated by the weight of the child shield, and the concentricity between the parent shield and the child shield Since the gap is formed by the holding structure, the child shield can be started smoothly without being caught between the parent shield and the child shield when the child shield starts moving. Further, the concentricity holding structure also makes the amount of crushing of the seal substantially uniform, so that it is possible to avoid occurrence of a defect in the sealing function. In addition, since the liner plate is integrally fixed to either the inner peripheral surface of the parent shield or the outer peripheral surface of the child shield, it is possible to prevent loosening of the liner plate with a simple fixing device and maintain concentricity. The number of parts of the structure can be reduced, and the structure can be simplified. In addition, when starting the child shield from the parent shield, it is only necessary to extend the child shield jack by using the child shield segment as a reaction force, so that the child shield can be started with a simple setup.

In the first invention, it is preferable that the liner plate is divided into a plurality in the circumferential direction. With this configuration, 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. Further, when the liner plate is provided on the outer peripheral surface of the child shield, the resistance when the child shield penetrates the ground is reduced, so that the propulsive force of the child shield can be reduced.

Next, a parent-child shield excavator according to a second invention has a rotatable child cutter head in a front part in a parent shield propelled into the ground by a parent shield jack, and an inner diameter of the parent shield. A parent-child shield excavator having a child shield having a smaller outer diameter and a concentricity holding structure provided in a radial gap between the parent shield and the child shield, wherein the concentricity holding structure is a child shield. Is formed by providing a large diameter portion on the front portion or a projection on the inner peripheral surface of the front portion of the parent shield. According to the second aspect, the liner plate can be omitted, and the backing material is filled between the rear part of the parent shield and the rear part of the child shield behind the concentricity holding structure, so that the concentric maintenance stroke can be further extended. In addition to being a support wall for the child shield segment. in addition,
If a large diameter portion is formed in the front part on the side of the daughter shield, the range of finishing with high precision by a machine is greatly reduced, so that the production cost can be greatly reduced. Further, by forming a tapered portion at the front end of the liner plate, the penetration resistance of the ground can be reduced, so that the propulsive force of the child shield can be reduced.

Further, the parent-child shield excavator according to the third invention has a rotatable child cutter head at the front in a parent shield propelled into the ground by a parent shield jack,
A parent-child shield excavator comprising: a child shield having an outer diameter smaller than an inner diameter of the parent shield; and a concentricity holding structure provided in a radial gap between the parent shield and the child shield. A seal is provided behind the holding structure. According to the third aspect, in the parent-child shield excavator having the concentricity holding structure as described above, it is possible to prevent water, earth and sand from entering the shield from outside the shield.

Next, a method for maintaining concentricity according to the fourth invention is as follows.
A concentricity maintaining method in the above-described parent-child shield excavator, wherein a backing material is filled around the inner peripheral side of the parent shield skin plate and the outer peripheral side of the child shield skin plate before starting the child shield. In addition to the support inner wall of the shield segment, the concentricity is maintained until the child shield comes out of the parent shield.

According to the concentricity maintaining method of the present invention, the backing material is filled around the inner peripheral side of the parent shield skin plate and the outer periphery of the child shield skin plate before starting the child shield. Since the support inner wall of the segment is used, even if the concentricity retaining structure comes off, it is possible to maintain concentricity until the child shield comes off from the parent shield.

[0013]

Next, a specific embodiment of a parent-child shield machine and a method for maintaining concentricity according to the present invention will be described with reference to the drawings.

FIG. 8 is a cross-sectional view showing a state in which the parent shield and the child shield are integrally excavated. FIG. 1 is a cross section in which preparation for starting the child shield is completed after excavation by the parent shield is completed, and the child shield starts. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, FIG. 3 is an explanatory view of a state in which the child shield starts moving from the parent shield, and FIG. 4 is an explanatory view of a state in which the child shield is detached from the parent shield. .

In these figures, 1 indicates a parent shield, and 2 indicates 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. The shield jack 3 allows the parent shield 1 to be propelled into the ground with the reaction of the parent segment 4 already assembled.

On the other hand, the child shield 2 is
And a gap 6 is 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. A liner plate 7 serving as a concentricity holding structure is interposed in the gap 6, and the concentricity of the parent shield 1 and the child shield 2 is secured by the liner plate 7.

The liner plate 7 is, for example, divided into 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.

At the tip of each liner plate 7, there is formed a tapered portion 7a having a diameter gradually decreasing toward the end so that the penetration resistance when penetrating the ground is reduced by the tapered portion 7a. In addition, a seal 8 is provided behind the liner plate 7. The seal 8 is annular and has the purpose of preventing water from entering the shield from outside the shield. Also, the second
As a means for maintaining concentricity, a method of filling a backing material around an inner periphery of a parent shield skin plate and an outer periphery of a child shield skin plate is used. The concentricity holding means using the first liner plate concentrically holds the front side of the child shield, but has no effect on the rear side of the child shield. The backing not only maintains concentricity during the stroke in which the child shield exits the parent shield, but also serves as a support wall for the child shield segments.

A plurality of child shield jacks 10 are provided in the circumferential direction on the inner side of the skin plate 2a of the child shield 2, and the child segments 4a assembled inside the parent segment 4 by the child shield jacks 10 are provided.
The child shield 2 is propelled into the ground by receiving a reaction force, and a child cutter head 12 is provided at a 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 driven to rotate by a child cutter head motor (not shown). After being taken into the chamber 1b, it is conveyed rearward by a not-shown 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 of the parent shield 1, and 14 denotes a child shield 2.
5 shows a child tail seal provided at the rear part of FIG.

Next, the operation will be described. When excavating a large-diameter tunnel, the parent shield 1 and the child shield 2 are simultaneously placed underground with the child shield 2 housed in the parent shield 1 as shown in FIG. And drilling while excavating a face with the parent cutter head 5 and the child cutter head 12. 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.

Next, after excavation of the large-diameter tunnel, when excavating the small-diameter tunnel following 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 periphery of the parent shield skin plate 1a and the child shield skin plate 2a is closed, and then the child segment 4a is assembled. Injection material 9 is injected to form a support wall for the child shield segment and as a means for maintaining concentricity of the child shield. The rear end of the child shield jack 10 abuts on the child segment 4a, the child segment 4a receives a reaction force, and the child shield 2 is propelled by the child shield jack 10 as shown in FIG. To start excavation. At this time, since the outer peripheral surface of the liner plate 7 fixed to the outer peripheral surface of the child shield 2 fits snugly into the inner peripheral surface 1c of the parent shield 1, the child shield 2 can be started smoothly.

A 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, so that there is no catch between them. , Skin plate 2a of child shield 2
Since the taper 7a is formed in advance at the front end of the liner plate 7 protruding from the outer peripheral surface, the penetration resistance when penetrating the ground is small, and there is no hindrance to the propulsion of the child shield 2.

As shown in FIG. 4, the liner plate 7 protruding from the outer peripheral surface of the child shield 2 separates from the inside of the parent shield 1 as shown in FIG. Has penetrated a considerable amount into the 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 without being displaced from the center of the parent shield 1. Even if the center of the child shield 2 is slightly deviated from the center of the parent shield 1, the gap 6 is provided in advance between the parent shield 1 and the child shield 2, so that there is no hindrance to 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 detached from the parent shield 1 as described above, the child tunnel is further excavated and a small diameter tunnel is excavated while assembling the child segment 4a with the excavation of the child shield 2. It becomes possible to excavate a small diameter tunnel following 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. It may be integrally attached over the entire surface. 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.

FIG. 7 shows that 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 at the front of the child shield 2 instead of providing the liner plate 7 on the outer periphery of the child shield 2. The large diameter portion 2b is formed to have the function of the liner plate 7. In this case, a tapered portion 7a is formed at 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 at the front portion on the child shield 2 side instead of the liner plate 7, but
The same function can be obtained even if provided on the parent shield 1 side.
Does not become a penetration resistance when excavating the child shield 2.

[Brief description of the drawings]

FIG. 1 is a sectional view of a parent-child shield machine 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 diagram showing a state in which a child shield starts from a parent shield of the parent-child shield excavator according to one embodiment of the present invention.

FIG. 4 is an explanatory view showing a state in which the child shield is detached from the parent shield of the parent-child shield excavator according to one 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.

FIG. 6 is a sectional view taken along line BB of FIG. 5;

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

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

[Explanation of symbols]

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

Continuation of the front page (72) Inventor Izumi Nishizawa 3-1-1 Ueno, Hirakata-shi, Osaka Komatsu Ltd. Osaka Plant (72) Inventor Norio Mitani 3-1-1 Ueno, Hirakata-shi, Osaka Komatsu Co., Ltd. (56) References JP-A-2-266092 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) E21D 9/06 301

Claims (5)

(57) [Claims] 1. A child shield having a rotatable child cutter head at a front portion and having an outer diameter smaller than the inner diameter of the parent shield is provided in a parent shield propelled into the ground by a parent shield jack, parent formed by providing a concentricity retaining structure in the radial direction of the gap between these parent shields and child shield
Child shield machine, forming the concentricity holding structure from a liner plate,
Also, if this liner plate is
To the outer surface of the shield
Parent-child shield machine, characterized in that that. 2. The parent-child shield excavator according to claim 1 , wherein the liner plate is divided into a plurality in the circumferential direction. (3)Propelled underground by parent shield jack
Child cutter head rotatable at the front inside the parent shield
Having an outer diameter smaller than the inner diameter of the parent shield.
Child shields are provided, and the parent shield and child shield
Parent having a concentricity retaining structure in the radial gap between them
A child shield machine,  The concentricity holding structure is provided with a large diameter portion or
By providing a projection on the inner peripheral surface of the front part of the parent shield
FormationCharacterized byParent-child shield machine. (4)Propelled underground by parent shield jack
Child cutter head rotatable at the front inside the parent shield
Having an outer diameter smaller than the inner diameter of the parent shield.
Child shields are provided, and the parent shield and child shield
Parent having a concentricity retaining structure in the radial gap between them
A child shield machine,  A seal is provided behind the concentricity holding structure.To provide
FeatureParent-child shield machine. 5. A method for maintaining concentricity in a parent-child shield machine according to any one of claims 1 to 4 ,
Before launching the child shield, 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 to form the support inner wall of the child shield segment, and the child shield is separated from the parent shield. A method of maintaining concentricity, wherein concentricity is maintained until the user exits.