JPS5918513B2 - Shield for tunnel excavation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tunnel excavator having a divided shield for excavating curved sections of tunnels.

When changing the direction of excavation with a conventional shield type tunnel excavator, it was necessary to first excavate the ground in the direction of the bend, and then use the shield jack to change the direction of the entire shield in that direction using the segments as supports. In addition, an excessively large cavity remains on the outside of the curved part, which cannot be solved even with a structure in which the shield is divided, and the structure of the connecting part is complicated, making it difficult to manufacture or use. There was a problem.

This invention has a simple structure and is easy to operate (even when digging a curved part of a tunnel with a tunnel excavator with a sturdy split shield, there is no need for excessive effort or wasted time, and there is a large cavity on the outside of the curved part). The present invention provides a shield for tunnel excavation that does not pose a risk of ground subsidence.

The present invention will be explained based on the embodiments shown in the drawings. A shield 3 of a shield type tunnel excavator is divided into a front shield 2 and a rear shield 3, and the front end of the rear shield 3 is connected to the skin of the rear end of the front shield 2. The skin plate 5 has a diameter smaller than that of the plate 4 and has a spherical outer circumferential surface. Inside the skin plate 5, connecting shafts 6, 6 whose central axes coincide with the diameter line of the skin plate 5 are provided at two upper and lower positions, and this connection The front shield 2 and the rear shield 3 are connected by fitting the shaft and the shaft holes 10° 10 of the connecting bearings 9, 9 provided on the same diameter line at the upper and lower parts of the connecting ring 7 at the rear of the front shield 2, respectively. concatenate,
An elastic sealing material 1 is provided between the skin plate 4 at the rear end of the shield 2 and the spherical skin plate 5 of the rear shield 30.
1 is installed to prevent earth and sand from entering from the outside at all times.

This connection structure may also include a spherical skin plate, a connection shaft provided in the front shield, and a connection bearing provided in the rear shield.

Also, between the front shield 2 and the rear shield 3, there are one or more steering jacks 1 on the left and right sides, respectively.
2.12 supports the front shield 2 by a support arm 13 supporting its cylinder end and a support arm 14 supporting its piston end.
and the rear shield 3, and a fixing device is provided between the front shield 2 and the rear shield 3. In this figure, the connecting ring 7 at the rear of the front shield 2 and the rear shield A fixing device 17 consisting of a connecting culm 18 threaded at both ends and an oak 19.19 attached to washers 15.16 provided on the left and right sides of the connecting side ring 8 at the front of 3.
Also, the cylinder end of the front ring 20 is attached to the inner peripheral part of the front shield 2, and the elastic support device 2 is attached to the front ring 20.
Shield jacks 22 supported by 1 so that their positions can be varied are mounted at equal intervals, and these jacks are connected to the connecting rings 7 and 8 of the front shield 2 and rear shield 3. A sprayer 23 is attached to a spherical hand at the tip of the piston portion and extends to the rear shield 3 side through the piston portion, and comes into contact with a segment 24.

Since this shield has the above-mentioned structure, when moving it straight, make sure that the central axes a and b of the front shield 2 and the rear shield 3 are aligned, as shown in Figure 3A, before using the fixing device. 17 fixes the front shield 2 and rear shield 3, extends the shield jack 22, and pushes the segment 24 with the spreader 23, so that the shield advances in a straight direction.

If you want to turn to the left (downward in the figure), first loosen the nut 19 of the fixing device 17, then turn to the right (downward in the figure), as shown in Figure 3B.
The steering jack 12 and shield jack 22 (in the upper part of the figure) are extended and the front shield 2 is rotated to the left about the connecting shaft 6 to align the center line a of the front shield 2 with the curve of the required curve. The relative position of the front shield 2 and the rear shield 3 is fixed by the fixing device 17 in a state where they are in contact with the center line C,
By pushing the segment 24 with the shield jack 22, the shield can be moved in the desired left direction.

Conventionally, this type of shield has been used, for example, when excavating a tunnel with a tunnel diameter D1 and a curve center line C, as shown in FIG. Depending on the position and progress state of the shield, there will be a difference in hl on the outside and h2 on the inside, and the inside h2 part needs to be excavated in a different way from this shield before bending the shield to this position. This wastes extra effort and time, and
After the tunnel was constructed, the l section remained hollow and there was a risk of causing soil damage, etc., and the shield length l
The ratio of //D to the diameter of the tunnel means that a shield with a small diameter will be thicker (and therefore the value of hlsh2 will be thicker (which will cause the loss mentioned above to be thicker). could not be solved even with the conventional split type shield, but in the shield of this invention, the front shield 2 and the rear shield 3 are always bent around the center M of the shield, so the position of the tunnel in this case Depending on the progress of the shield, there is only a slight difference between h1' on the outside and h2' on the inside, so the problems caused by over-digging and cavities as mentioned above can be almost eliminated, and at the same time, the rear shield 30 spherical skin plate 5 and the skin plate 4 of the front shield 2 always swing with the same amount of gap between them, so the elastic seal material 11 provided between them can effectively prevent dirt from entering the inside of the shield. The shield is connected only by the upper and lower connecting shafts, and does not use any complicated hydraulic equipment, so it is robust, easy to operate, reliable, and has few breakdowns (which satisfies the needs of this type of civil engineering machinery).

[Brief explanation of drawings]

The figures show one embodiment of the shield for tunnel excavation of the present invention. Figure 1 is an explanatory diagram of a front vertical cross section of the shield of the present invention, Figure 2 is a sectional view taken along the line n-■ of Figure 1, and Figure 3 is a top view showing the state of direction control of the shield of this invention.
B shows the case of straight travel, and B shows the case of curved travel. FIG. 4 is a comparative explanatory diagram of the shield of the present invention and the conventional shield in the case of curved travel. 1... Shield for tunnel excavation of this invention, 2
...Front shield, 3 ... Rear shield, 5 ... Spherical skin plate, 6 ...
Connection shaft, 9... Connection bearing, 12... Steering jack, 17... Fixing device, 22
...Shield jack, 23...Spreader, 25...Conventional integrated shield.

Claims (1)

[Claims] 1. The shield of the shield type tunnel excavator is divided into a front part and a rear part, and 5 parts of the skin plate having a spherical outer peripheral surface at the front end of the rear shield 3 and 4 parts of the skin plate at the rear end of the front shield 2 are divided. In combination, connection bearings 9°9 having shaft holes 10 at the tips are provided at the upper and lower parts of the connecting side ring 7 at the rear of the front shield 2, and at the inner upper and lower parts of the skin plate 5, the bearings 9°9 are aligned with the diameter line thereof. Connection shafts 6, 6 having central axes are provided, and are fitted into the shaft holes 10, 10 of the connection bearings 9, 9, respectively, to connect the front shield 2 and the rear shield 3, and connect the front shield 2 and the rear shield. This shield for tunnel excavation is provided with a fixing device 17 at the left and right positions between the front shield 2 and the front shield 2.