JP4839252B2 - Tunnel excavator - Google Patents

Description

  The present invention relates to a tunnel excavator for excavating a tunnel having a rectangular cross section such as a road tunnel, an underpass, and a common groove.

As is well known, it is often reasonable to make the cross-sectional shape of a relatively small tunnel as described above in an urban area a rectangular cross section rather than a circular cross section. As a tunnel excavator for excavating a tunnel, for example, as shown in Patent Documents 1 to 4, a kind of screw cutter having a cutting bit on the outer peripheral portion is arranged in a substantially horizontal direction perpendicular to the excavation direction. In particular, those having such screw cutters in two upper and lower stages are known.
Japanese Patent No. 2502340 Japanese Patent Publication No. 7-59878 Japanese Patent Laid-Open No. 11-229774 Japanese Patent No. 3667717

According to the excavator as described above, a tunnel having a rectangular cross section can be excavated as it is, and therefore, it is not necessary to excavate a cross section more than necessary as in the case of excavating into a circular cross section by a normal shield machine. As compared with the case of the above, shallow excavation is also possible, which is suitable for application to the construction of various urban tunnels as described above.
However, the conventional excavators shown in Patent Documents 1 to 4 need to pay sufficient attention to the collapse of the upper ground, especially when excavating a rectangular tunnel at a shallow depth, and there is room for improvement in that respect. It is left.

That is, each of the above conventional excavators excavates the ground in the width direction with a horizontal screw cutter, and at the time of excavation, the excavated sediment is collected from both sides to the center side at the face and then transferred backward. Therefore, in the face, there is a considerable unevenness in earth pressure in which the earth pressure increases at the center, but the earth pressure decreases on both sides.
In this way, in conventional excavators, uneven earth pressure due to the lateral movement of excavated sediment at the face is inevitable, so the earth pressure on both sides of the face is excessive depending on the ground conditions and excavation depth. As a countermeasure for this, for example, ground improvement work for the upper ground and support reinforcement for the upper face of the face may be required. It is also an obstacle to reducing the construction cost.

  In view of the above circumstances, when the present invention excavates a tunnel with a rectangular cross section by using this type of tunnel excavator, effective and appropriate tunnel excavation that can prevent uneven earth pressure in the face and surely prevent collapse of the upper ground. The purpose is to provide a machine.

  The present invention is a tunnel excavator formed by arranging a plurality of cutters having a substantially horizontal rotation axis perpendicular to the excavation direction in the front part of the excavator body and arranging them in parallel in a plurality of stages. Among the cutters, at least the uppermost cutter is provided with a pair of spiral blades each provided with a stirring blade for stirring the excavated earth and sand, the spiral directions being opposite to each other. It is characterized by comprising.

In the present invention, in the excavator body behind the uppermost cutter, the horizontal transfer device for transferring the excavated earth and sand arranged substantially parallel to the cutter and stirred by the stirring blades of the cutter in the width direction And a main transfer device for further transferring the excavated earth and sand transferred by the lateral transfer device to the rear side.
In addition, among the plurality of cutters, other cutters excluding the uppermost cutter have spiral blades for transferring excavated earth and sand in the width direction of the face, and the cutters are disposed inside the excavator body. It is preferable to provide a main transfer device for transferring the excavated earth and sand transferred in the width direction by the spiral blade.
Further, it is preferable that at least a part of a plurality of cutters provided at the front portion of the excavator body is provided so as to be able to advance and retract in the front-rear direction.
Furthermore, a rotary cutter having a rotation axis parallel to the excavation direction may be provided in front of a plurality of stages of cutters provided at the front of the excavator body.

According to the present invention, a tunnel having a desired rectangular cross section can be efficiently excavated by each stage cutter, and the uppermost cutter is provided with a pair of agitating blades with a pair of reverse spiral blades. Since the cutter does not actively move the excavated sediment in the width direction only by stirring the excavated sediment, the excavated sediment is not actively transported in the lateral direction at the upper part of the face, so this type of conventional In the excavator, an unavoidable bias of earth pressure is inevitably generated, and it is possible to prevent a situation such as a collapse of the upper ground due to an excessive decrease in earth pressure.
As a result, according to the tunnel excavator of the present invention, it is possible to eliminate the need for ground improvement work and support strengthening that were required in the case of excavation of a rectangular cross-section tunnel with this type of conventional excavator. In addition, it becomes possible to carry out shallow depth drilling more stably and safely.

One embodiment of the tunnel excavator of the present invention is shown in FIGS. This is for excavating a tunnel with a rectangular cross section, such as a box culvert. Basically, like a normal shield machine, a concrete box 1 is assembled and assembled after excavating the ground. It is configured to take a reaction force from a box 1 that has already been used.
That is, the basic configuration of the tunnel excavator of the present embodiment is the same as that of a normal shield machine, with various equipment necessary for tunnel excavation inside the excavator body 2 that matches the cross-sectional shape of the tunnel to be built. Almost everything is accommodated, and a cutter for ground excavation is arranged at the front of the excavator body 2.

  Specifically, the excavator main body 2 uses a rectangular cylindrical skin plate 5 that matches the cross-sectional shape of the tunnel to be excavated as an outer shell, and presses the box 1 that has already been constructed at the rear thereof to generate a reaction force therefrom. A number of propulsion jacks 6 for propulsion are provided (20 in the illustrated example). In addition, the excavator body 2 is provided with an erector device 7 for use in assembling the box 1, as well as devices and accessories necessary for tunnel excavation.

  In the tunnel excavator of this embodiment, as a cutter disposed at the front part of the excavator body 2, a main cutter 3 having a plurality of stages (five stages in the illustrated example) for excavating the face into a rectangular cross section, A sub-cutter 4 arranged at the front is also used.

  The main cutters 3 at each stage are arranged substantially horizontally with the rotation axis orthogonal to the excavation direction. As shown in FIGS. 2 to 4, a set of two screw types are symmetrically arranged. Thus, both end portions thereof are rotatably supported with respect to the side frame 8 and the center frame 9, and are rotationally driven by an oil motor 10 incorporated inside these end portions.

  Each of the main cutters 3 of each stage excavates the face in the width direction and excavates a tunnel having a rectangular cross section as a whole. The other four stages below are slightly different in configuration, and the excavation earth and sand transfer mechanism is also different.

That is, as the four-stage main cutter 3 excluding the uppermost stage, a normal screw cutter 3B is used as shown in FIG. 3, and a series of spiral blades 12 are provided around the shaft portion 11, and A cutting bit 13 is attached to the outer peripheral portion of the spiral blade 12, and this screw cutter 3 </ b> B can excavate the ground by the cutting bit 13 by its own rotation and simultaneously transfer the excavated soil by the spiral blade 12 in the axial direction. It is said that. And since these screw cutters 3B are symmetrically arranged across the center, the excavated earth and sand excavated by these screw cutters 3B are respectively transferred from the center side toward both sides.
Further, each stage side frame 8 supporting one end of the screw cutter 3B of each stage receives the excavated earth and sand transferred to the side by the screw cutter 3B of each stage and further transports it to the rear to carry it out. As the main transfer device for discharging the soil, it also serves as a casing for the screw conveyor 14, and the excavated earth and sand by the screw cutters 3 B at each stage is indicated by the arrows in the figure. Are continuously transferred from the side toward the rear, and are discharged from the earth discharge port 15 provided at the rear portion of the screw conveyor 14 and carried out.

On the other hand, as the uppermost main cutter 3, a stirring cutter 3A having a configuration in which a stirring blade 17 is provided around the shaft portion 16 as shown in FIG. 2 is employed, and the stirring blade 17 has a spiral direction opposite to that of the upper cutter. The two pairs of spiral blades 18 are configured, and the directions of the spiral blades 18 are substantially reversed at regular intervals.
A cutting bit 19 is also attached to the outer peripheral part of each spiral blade 18 constituting the stirring blade 17, and the uppermost stirring cutter 3A can also excavate the ground by its own rotation, but the excavated soil is 2 The pair of spiral blades 18 are intended to be transported in opposite directions, so that eventually they are not transported in any direction and are merely stirred by the stirring blade 17.
Further, behind the uppermost stirring cutter 3A, a set of two paddle screws 20 are symmetrically arranged as a lateral transfer device for transferring the excavated earth and sand to both sides while further stirring them. The excavated earth and sand transferred to both sides by these paddle screws 20 are moved backward by a screw conveyor 14 as a main transfer device incorporated in the side frame 8 in the same manner as that attached to the lower screw cutter 3B. It is transported and discharged. That is, since the uppermost stirring cutter 3A itself cannot stir the excavated sediment and cannot effectively transfer the excavated sediment, a paddle screw 20 as a lateral transfer device is disposed behind the agitated sediment 3A. Transport to the side of the can be performed without any trouble.

In front of the stirring cutter 3A as the main cutter 3 and the screw cutter 3B of each stage described above, the sub cutter 4 for excavating a range that cannot be effectively excavated by the main cutter 3 is disposed. Therefore, a general rotary cutter is adopted as the sub cutter 4. The rotary cutter as the sub-cutter 4 is provided on the side frame 8 supporting the end of the main cutter 3 at each stage and the tip of the rotary shaft 21 disposed in the center frame 9. The ground in front of the center frame 9 is excavated.
The rotating shaft 21 incorporated in the center frame 9 is dedicated to the sub-cutter 4 and is rotated by an oil motor 22 provided at the rear part of the center frame 9. 8 is also used as the screw conveyor 14 (that is, the rotary shaft 21 of the sub cutter 4 is formed with spiral blades for transferring earth and sand. In other words, the screw conveyor 14 is The screw conveyor 14 and the sub cutter 4 are rotated by an oil motor 22 provided at the rear portion of the side frame 8.

Further, the main cutter 3 and the sub-cutter 4 of each stage configured as described above are arranged in an inclined state with respect to the vertical surface so that the upper cutter side is located slightly forward as shown in FIG. Although it is basically arranged, it may be fixedly installed in that state, but the main cutter 3 and the sub cutter 4 at each stage can be independently advanced and retracted in the front-rear direction as shown in the illustrated example. preferable.
That is, in the illustrated example, the side frame 8 and the center frame 9 supporting both ends of each main cutter 3 are further connected by the rear frame 23, and the main cutters 3 at each stage are connected by the whole. And the support frame 24 which supports the sub cutter 4 is comprised. In the uppermost stage, both the stirring cutter 3A and the paddle screw 20 behind the stirring cutter 3A are supported by the support frame 24.
An advance / retreat jack 26 is interposed between the support frame 24 of each stage and the main frame 25 in the excavator body 2, and the operation of the advance / retreat jack 26 of each stage causes the support frame 24 of each stage to be interposed. The main cutter 3 and the sub cutter 4 at each stage are moved forward and backward in the forward and backward direction, so that each can be arranged at an optimum position according to the ground condition and the excavation work process. In this way, it is possible to arrange not only the upper side so that it is located slightly forward, but also the lower side so that it is located slightly forward, or all the positions can be aligned. .
In addition, since the screw conveyor 14 as a main transfer device is incorporated in the support frame 24 of each stage as described above, when the support frame 24 of each stage is moved forward and backward, the screw conveyor 14 of each stage is simultaneously provided. Will also move forward and backward.

According to the tunnel excavator of the present embodiment, a tunnel having a desired rectangular cross section can be efficiently excavated by the main cutter 3 and the sub cutter 4, and in particular, the stirring cutter 3A is used at the uppermost stage of the main cutter 3. Since the agitating cutter 3A is provided with the agitating blade 17 by a pair of oppositely facing spiral blades 18, the uppermost agitating cutter 3A does not actively transfer the excavated sediment to the side. Therefore, in the conventional excavator using a screw cutter, it is inevitable that the earth pressure in the width direction at the face is inevitably generated, and the situation such as the collapse of the upper ground due to the excessive decrease in the earth pressure. Can be prevented in advance.
Of course, although the uppermost stirring cutter 3A cannot effectively transfer the excavated sediment, the excavated sediment is naturally taken into the excavator main body 2 by the excavation of the excavator main body 2, and as a lateral transfer device behind it. The paddle screw 20 and the screw conveyor 14 as the main transfer device are provided in the excavator body 2, so that the excavation earth and sand can be transferred from the uppermost stage of the face without any trouble, and the upper ground at that time can be transferred. The supporting effect is naturally sufficiently secured by the skin plate 5.
Therefore, according to the tunnel excavator of the present embodiment, it becomes possible to eliminate the ground improvement work and the support strengthening that are necessary in the case of excavation of a rectangular cross-section tunnel with this type of excavator of the related art. In addition, shallow depth drilling can be carried out more stably and safely.

  Since the lower-stage screw cutter 3B performs the lateral transfer as usual, it is assumed that the earth pressure is biased on the lower-stage side, but at least as described above. In the upper stage, the earth pressure is stably maintained over the entire width of the face, and in particular, if the uppermost stirring cutter 3A is arranged so as to protrude forward from the lower screw cutter 3B, the lower screw cutter The earth pressure of the upper ground of 3B will be maintained stably over a wide range.

  Although one embodiment of the present invention has been described above, the above embodiment is merely a preferred example, and the present invention is not limited to the above embodiment. For example, within the scope of the present invention, for example: Various design changes and applications as listed in (1) are possible.

  In the above embodiment, the main cutter 3 for excavation in a rectangular cross section is arranged over five stages, but it goes without saying that the number of stages may be arbitrarily increased and decreased, and the rotation axis is used as the main cutter of each stage in the excavation direction. As long as the face can be excavated in the width direction by its outer peripheral portion as a substantially horizontal direction orthogonal to the above, as long as it is not limited to the screw type as in the above embodiment, various types of similar types A cutter, such as a ribbon cutter or a paddle cutter, can be used in the same manner, and different types of cutters may be appropriately combined.

  In the above embodiment, in order to effectively prevent uneven earth pressure, only the uppermost cutter is a stirring cutter 3A dedicated to stirring that does not actively transfer excavated earth and sand, and behind that is a paddle screw as a lateral transfer device. However, not only the uppermost cutter but also some or all of the other cutters may be used exclusively for stirring. A transfer device may be provided.

  In the above embodiment, the paddle screw as the lateral transfer device and the screw cutter 3B on the lower stage side are both symmetrically arranged as a set, and the excavated earth and sand is transferred from the center side toward both sides. As shown in Patent Documents 1 to 4, the excavated earth and sand may be laterally transferred from both sides toward the central side and transferred backward in the central portion, or each stage may be constituted by a single main cutter. The excavated earth and sand may be simply transferred in one direction.

  In the above embodiment, the paddle screw 20 is used as the horizontal transfer device, and the screw conveyor 14 is used as the main transfer device. However, the types of the horizontal transfer device and the main transfer device are arbitrary, and excavation from the cutters at each stage. When the earth and sand can be taken into the excavator body without any trouble and conveyed to the rear, the main transfer device is not necessarily provided at every stage.

  In the above embodiment, the rotary cutter as the sub cutter 4 is provided together. However, the type and installation position of the sub cutter can be appropriately changed including the omission of the sub cutter.

It is a side view showing a schematic structure of a tunnel excavator which is an embodiment of the present invention. FIG. 2 is a plan sectional view (II-II line view in FIG. 1) showing the uppermost cutter. FIG. 3 is a plan sectional view (a view taken along line III-III in FIG. 1) showing the lower stage side cutter. FIG. FIG.

Explanation of symbols

1 Box 2 Excavator body 3 Main cutter (multi-stage cutter)
3A Stirring cutter (top cutter)
3B Screw cutter (lower cutter)
4 Sub cutter (Rotating cutter)
5 Skin Plate 6 Propulsion Jack 7 Elector Device 8 Side Frame 9 Center Frame 10 Oil Motor 11 Shaft 12 Spiral Blade 13 Cutting Bit 14 Screw Conveyor (Main Transfer Device)
15 Discharge port 16 Shaft 17 Stirring blade 18 Spiral blade 19 Cutting bit 20 Paddle screw (lateral transfer device)
21 Rotating shaft 22 Oil motor 23 Rear frame 24 Support frame 25 Main frame 26 Advance / retreat jack

Claims (5)

A tunnel excavator in which a cutter having a substantially horizontal rotation axis orthogonal to the excavation direction is arranged in the vertical direction at the front of the excavator main body and is mounted in parallel in a plurality of stages,
Among these multi-stage cutters, at least the uppermost cutter is provided with a stirring blade for stirring the excavated earth and sand, and each of the stirring blades has a spiral direction opposite to each other. Tunnel excavator characterized by consisting of a pair of spiral blades. The tunnel excavator according to claim 1,
A lateral transfer device is provided in the excavator main body behind the uppermost cutter for transferring the excavated earth and sand agitated by the agitating blades of the cutter in the width direction, substantially parallel to the cutter, and A tunnel excavator comprising a main transfer device for further transferring the excavated earth and sand transferred by the horizontal transfer device to the rear side. The tunnel excavator according to claim 1 or 2,
Among the multi-stage cutters, the other cutters except the uppermost one have spiral blades for transferring excavated earth and sand in the width direction of the face, and the inside of the excavator body has spirals of these cutters. A tunnel excavator comprising a main transfer device for transferring the excavated earth and sand transferred in the width direction by blades to the rear. The tunnel excavator according to any one of claims 1 to 3,
A tunnel excavator characterized in that at least a part of a plurality of cutters provided at a front portion of an excavator body is provided so as to be able to advance and retreat in the front-rear direction. The tunnel excavator according to any one of claims 1 to 4,
A tunnel excavator characterized in that a rotary cutter having a rotation axis parallel to the excavation direction is provided in front of a plurality of cutters provided at the front of the excavator main body.

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