JPH0378919B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a shield excavator for excavating a tunnel having a cocoon-shaped cross section.

BACKGROUND ART Conventionally, when excavating a tunnel with a wide cross section, for example, a two-lane subway tunnel, as shown in FIG. As shown in Figure 7, two small-diameter tunnels 52 were excavated in parallel. By the way, in the former case, the tunnel diameter becomes large, the face becomes easy to collapse, the cost of the excavator itself increases, and there is a lot of wasted space inside the tunnel. Since it requires a standalone shield excavator, it has disadvantages such as increased running costs and a longer construction period. As a method to eliminate such drawbacks, it is conceivable to make the cross-sectional shape of the tunnel into a shape in which two cylindrical tunnels are arranged on the left and right, and the opposing sides overlap each other with a predetermined width, that is, a cocoon shape. By the way, as a shield excavator for excavating a tunnel in a cocoon shape, as shown in FIG. It is necessary to form them into spokes so that they do not interfere with each other.

Problems to be Solved by the Invention As mentioned above, if the face plate of the cut head is spoke-shaped, it cannot sufficiently support the face.
There was a problem that required a large amount of soiling agent.

Therefore, an object of the present invention is to provide a shield tunneling machine that can solve the above problems.

Means for Solving the Problems In order to solve the above problems, the shield tunneling machine of the present invention connects at least two cylindrical shield main bodies in parallel with each other so that their opposing sides partially overlap. The cutter heads rotatably provided at the front ends of both shield main bodies are arranged at different positions in the front-rear direction, and the face plates of each cutter head are circular. The rear surface of the front cutter head located at the front is formed into a conical shape that projects rearward, and the front surface of the rear cutter head located at the rear is provided in a conical shape that projects forward.

Operation In the above configuration, when each cutter head is operated to move the shield body forward, a tunnel having a cocoon-shaped cross section is excavated. According to this structure, at least two cutter heads are arranged at different positions in the front and back, and the cutter head face plate is formed into a circular shape, so that even if the ground is soft and highly collapsible, the face can be sufficiently supported. In addition, since the opposing surfaces of the two cutter heads are conical, the gap between the overlapping parts is narrowest at the center and widens toward both ends. Compared to an arrangement in which two flat cutter heads having the same thickness are arranged, it is possible to prevent dirt, gravel, etc. from getting caught in the overlapping portions of the cutter heads, that is, blockage.

Embodiment Hereinafter, an embodiment of the present invention will be described based on the drawings. In FIGS. 1 and 2, 1 has a cocoon-shaped cross-section formed by connecting two cylindrical shield main bodies 2 and 3 in left and right parallel to each other so that their opposing sides partially overlap. This is the main body of the shield. That is, when the radius of each cylindrical shield main body part 2, 3 is R, and the distance between the centers of both shield main parts 2, 3 is L, R and L are selected so as to satisfy the relationship R<L<2R. be done. Reference numeral 4 denotes a partition wall for forming a pressure chamber provided in the vicinity of the front ends of both the shield main bodies 2 and 3 and extending over both. Reference numeral 5 designates a front cutter head disposed at the front end of one of the shield main body portions 2, and is rotatably supported by the partition wall 4. That is, the front cutter head 5 is composed of a completely circular face plate 6 and a rotating shaft 7 protruding from the rear of the face plate 6, and this rotating shaft 7 is fixed to the partition wall 4 and the auxiliary wall 27. It is supported within the holding cylinder 8 via a bearing (not shown). 9 is attached to the front end of the other shield main body 3 and also to the front cutter head 5.
With the rear cutter head located in a more rearward position,
It is supported by the partition wall 4 and the auxiliary wall 27 so as to be rotatable and slidable in the front-rear direction. That is, the rear cutter head 9 has a completely circular face plate 10 and a face plate 1.
0 A holding cylinder 13 is composed of a rotating shaft body 11 that projects rearward, and this rotating shaft body 11 is slidably inserted into a support cylinder 12 fixed to the partition wall 4.
The partition wall 4 is further provided with a cylinder device 14 for moving the holding cylinder 13 forward and backward to move the rear cutter head 9 forward and backward. The rear surface 6a of the face plate 6 of the front cutter head 5 is formed in a conical shape that projects rearward, and the front surface 10a of the face plate 10 of the rear cutter head 9 is formed in a conical shape that projects forward. Further, the front end of each shield main body part 2, 3 is extended to the front of the face plates 6, 10 of each cutter head 5, 9, and the part of this extended part between the face plates 6, 10 and the partition wall 4 is formed as a pressure chamber 15. Therefore, the shield main body 2 on the front cutter head 5 side projects more forward than the shield main body 3 on the rear cutter head 9 side. 16,1
Reference numeral 7 denotes a motor for rotating the cutter heads 5, 9, which is attached to support brackets 18, 19 protruding from each holding cylinder 8, 13, and a pinion 2 attached to each output shaft 16a, 17a.
0 and 21 are meshed with ring gears 22 and 23 attached to the rear ends of the rotating shaft bodies 7 and 11, respectively. Although the motors 16 and 17 are supported by the holding cylinders 8 and 13, the motor 16 for driving the front cutter head 5, which does not move back and forth, may be directly attached to the shield body 2. In addition, as shown in FIG. 2, each of the face plates 6 and 10 has a plurality of slits 24 and 25 formed in a radial manner for taking in soil, and the edges of each of the slits 24 and 25 have a number of cutout bits. (Only a part is shown in the figure)2
6 is installed.

In the above configuration, when excavating a tunnel with a cocoon-shaped cross-section, each motor 16, 17
Excavation can be carried out by rotating each cutter head 5, 9. At this time, slurry is injected into the pressure chamber 15 from a mud feeding pipe (not shown) to support the face, and the excavated earth and sand is discharged from a mud draining pipe (not shown). If gravel or the like gets caught between the cutter heads 5 and 9 during excavation, the jamming can be easily released by moving the rear cutter head 9 rearward using the cylinder device 14 as shown by the imaginary line.

By the way, since the mutually opposing surfaces of both cutter heads 5 and 9 are made conical, the gap between the mutually overlapping parts is narrowest in the center and widens toward both ends. As shown in Fig. 3, compared to the arrangement of two ordinary flat plate-shaped cutter heads 31 and 32 (having the same thickness over the entire surface), there is a tendency for dirt, gravel, etc. to get caught in the overlapping parts of the cutter heads. Blockage can be prevented. Furthermore, since the opposing sides of both cutter heads 5 and 9 are conical, as shown in FIG. 3, when the total thickness T ₁ of both cutter heads 5 and 9 is flat as shown in FIG. Thickness of T ₂
Therefore, the thickness of the pressure chamber 15 is also thinner, and the strength of the rotary shafts 7, 11 for driving the cutter head and the skin plate of the pressure chamber 15 portion can be improved, and the overall length of the shield body 1 can be shortened.
Furthermore, the displacement between the double-sided plates 6 and 10 can be minimized, which is effective in equalizing the resistance during excavation.

In the above embodiment, two cylindrical shield main bodies are arranged side by side in the horizontal direction, but they may be arranged in parallel in the vertical direction, for example, and as shown in FIG.
The cylindrical shield main body parts 41, 42, 43 may be arranged in parallel in the horizontal direction (or vertical direction). Furthermore, four or more cylindrical shield main bodies can be arranged in parallel.

Effects of the Invention According to the above configuration of the present invention, it is possible to excavate a tunnel with a cocoon-shaped cross section, so the overall tunnel width is narrower than in the case of excavating two circular tunnels. At the same time, the amount of excavation is reduced, which is advantageous in terms of economy. In addition, since at least two cutter heads are arranged at different positions in the front and back, and the cutter head face plate is configured in a circular shape, even if the ground is soft and highly collapsible, the face can be sufficiently supported, and
The amount of mud-forming agent required is much less than that required for those with spoke-shaped face plates. Furthermore, since the mutually opposing surfaces of the cutter heads are conical, the gap between the overlapping parts is narrowest at the center and widens toward both ends, so that, for example, the thickness is the same over the entire length. Compared to an arrangement in which two flat cutter heads are arranged, it is possible to prevent dirt, gravel, etc. from getting caught in the overlapping parts of the cutter heads, that is, blockage.

[Brief explanation of drawings]

1 to 3 show one embodiment of the present invention, FIG. 1 is a horizontal sectional view, and FIG. 2 is a -
3 is a schematic sectional view showing the thickness of the cutter head, FIG. 4 is a schematic plan view of a comparative example, FIG. 5 is a horizontal sectional view of another embodiment, and FIGS. 6 to 8 are conventional For example, FIGS. 6 and 7 are cross-sectional views of a tunnel, and FIG. 8 is a front view of a cocoon-shaped shield tunneling machine. 1...Shield body, 2, 3...Shield body part,
4... Bulkhead, 5... Front cutter head, 6... Face plate, 6
a... Rear surface, 9... Rear cutter head, 10... Face plate,
13... Holding cylinder, 14... Cylinder device, 15... Pressure chamber.

Claims (1)

[Claims] 1 At least two cylindrical shield main bodies are connected in parallel with each other so that their opposing sides partially overlap to form a shield main body having a cocoon-shaped cross section, and The positions of the rotatably provided cutter heads are different from each other in the front-rear direction, the face plates of each cutter head are respectively circular, and the rear surface of the front cutter head located at the front is formed into a conical shape protruding rearward. A shield excavator characterized in that the front surface of the rear cutter head located at the rear is formed into a conical shape that projects forward.