Shield tunneling machine

Abstract

To provide a shield tunneling machine that can stabilize the tunnel face even if the condition of the mud or pressure is not sufficient. [Solution] The earth pressure balance shield 1, used as a shield tunneling machine, comprises a rotating cutter rotation shaft 4, cutter spokes 51 and 52 extending radially from the cutter rotation shaft 4, and cutter bits 53, ... attached to the front of the cutter spokes 51 and 52 for excavating the ground. The cutter bits 53, ... are arranged to excavate the ground along a curved shape that is convex towards the front, extending from the base relative to the cutter rotation shaft 4 toward the outer edge. The cutter spokes 51 are bent into a curved shape that is convex towards the front, extending from the base relative to the cutter rotation shaft 4 toward the outer edge, so that the cutter bits 53, ... excavate the ground along this curved shape.

Description

Technical Field

[0001] The present invention relates to a shield tunneling machine capable of stabilizing a working face.

Background Art

[0002] Conventionally, in a shield tunneling machine, a cutter disposed on the front surface of a substantially cylindrical shield outer cylinder excavates the working face of a tunneling section. This cutter has cutter spokes extending radially from the central portion, and excavation bits are attached to the front surface of the cutter spokes.

[0003] Then, the cutter is rotated to excavate the soil of the working face, the excavated sediment and the mud conditioning material injected into the chamber are kneaded and mixed by stirring blades attached to the back surface of the cutter to form mud, and excavation is performed while pressing the working face with the pressure of the mud (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problem to be Solved by the Invention

[0005] In such a conventional shield tunneling machine, management of the state and pressure of mud is important for holding the working face during tunneling. However, due to factors such as mucking troubles, it may not be possible to maintain the state and pressure of mud in a sufficient condition, and the stability of the working face may not be maintained. When the stability of the working face cannot be maintained as described above, the conventional cutter shape has a problem that loosening and collapse are likely to occur particularly in the upper part of the working face and the front central part of the cutter face.

[0006] Therefore, the present invention aims to provide a shield tunneling machine that can stabilize the tunnel face even if the condition of the mud or pressure is not sufficient. [Means for solving the problem]

[0007] To achieve the above objective, the shield tunneling machine of the present invention comprises a rotating cutter rotation shaft, cutter spokes extending radially from the cutter rotation shaft, and a cutter bit attached to the front surface of the cutter spokes for excavating the ground, wherein the cutter bit is arranged to excavate the ground along a curved shape that is convex towards the front side, from the base to the outer edge relative to the cutter rotation shaft. [Effects of the Invention]

[0008] Thus, the shield tunneling machine of the present invention comprises a rotating cutter rotation shaft, cutter spokes extending radially from the cutter rotation shaft, and a cutter bit attached to the front surface of the cutter spokes for excavating the ground. The cutter bit is arranged to excavate the ground along a curved shape that is convex towards the outer edge from the base relative to the cutter rotation shaft, with the front side being convex. With this configuration, the tunnel face can be stabilized by the ground arch effect of the ground, even if the condition of the mud and pressure are not sufficient. [Brief explanation of the drawing]

[0009] [Figure 1] This is a longitudinal cross-section of a shield tunneling machine. [Figure 2] This is a front view of a shield tunneling machine. [Figure 3] This is an explanatory diagram that describes how to determine the shape of a circular arc. [Figure 4] This is an explanatory diagram illustrating specific examples of how to determine the arc shape. (a) shows the case with an outer excavation diameter of φ3000 mm, (b) shows the case with an outer excavation diameter of 6000 mm, and (c) shows the case with an outer excavation diameter of 9000 mm. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. However, the components described in the following embodiments are illustrative and are not intended to limit the technical scope of the present invention to them alone. Here, the term "earth pressure balance shield" is a concept that includes two types: earth pressure balance shields and mud earth pressure balance shields (mud pressure shields). Mud earth pressure balance shields (mud pressure shields), which make up the majority of earth pressure balance shields, have a cutter head of the cutter spoke type without a faceplate.

[0011] This earth pressure shield is equipped with a bulkhead, shield propulsion jacks, and a soil removal device. The pressure inside the chamber is adjusted by the propulsion force provided by the shield propulsion jacks and the amount of soil removed by the soil removal device. 1) Conversion of excavated soil into plastically fluidized soil (mud). 2) Stabilization of the tunnel face by filling and pressurizing the chamber with this mud. 3) Excavation by maintaining and controlling the mud pressure inside the chamber These three are the basic conditions for face stability in earth pressure balance shield tunneling. [Examples]

[0012] (Configuration of a shield tunneling machine) First, the overall configuration of the earth pressure balance shield (mud earth pressure shield) 1 used as the shield tunneling machine in this embodiment will be explained using Figures 1 and 2. As shown in Figures 1 and 2, the earth pressure balance shield 1 mainly consists of a skin plate (shield body cylinder) 2, a bulkhead 3, a cutter rotation shaft 4, a cutter head 5, a cutter drive unit 6, a soil removal device 7, and a shield propulsion jack 8. In the following embodiment, an example using the so-called center shaft support method for supporting the cutter head 5 will be described, but it is not limited to this, and a curved cutter head 5 can also be applied to intermediate support methods, outer circumference support methods, central support methods, or eccentric multi-axis support methods.

[0013] The partition wall 3 is a steel wall that isolates the chamber 13 (described later), which is filled with mud, from the internal space of the shield machine, and has a bearing 11 for the cutter rotation shaft 4 installed in the center. Furthermore, the partition wall 3 in this embodiment is equipped with two fixed stirring blades 31, 31 at the top and bottom. The lower fixed stirring blade 31 is configured to be rotatable (rotatable on its own axis), and a high-pressure injection nozzle 32a for mud preparation and abrasive material is installed on its side, as is a high-pressure injection nozzle 32b for washing, which is used to inject mud preparation material and abrasive material into the chamber 13.

[0014] The cutter rotating shaft 4 is rotatably supported by a bearing 11 provided in the partition wall 3 and a bearing provided at the rear of the gearbox 12. In this embodiment, two high-pressure mud-making nozzles 41, 41 (one vertically oriented, the other diagonally rearward oriented) are installed on the side of the cutter rotating shaft 4 to inject mud-making material into the chamber 13.

[0015] The cutter rotation shaft 4 is connected to the cutter drive unit 6. The cutter drive unit 6 includes a gearbox 12 installed on the rear side of the partition wall 3, a rotary drive source 60 connected to the gearbox 12, and a reduction gear (located inside the gearbox 12; not shown) interposed between the output shaft of the rotary drive source 60 and the cutter rotation shaft 4.

[0016] The cutter head 5 of this embodiment is a cutter spoke type without a faceplate, and has four arc-shaped spokes 51 on the front side (face side), four straight spokes 52 extending from the back side (bore side) of the four arc-shaped spokes 51, a plurality of cutter bits 53 provided on the front of the arc-shaped spokes 51, a fishtail bit 54 provided in the center of the front of the arc-shaped spokes 51, a plurality of stirring blades 55 provided on the back of the straight spokes 52, and a copy cutter 56.

[0017] That is, the cutter head 5 is of a cutter spoke type, and primary consideration is given to achieving plastic fluidization of excavated soil. Specifically, the arc-shaped spoke 51 serving as a cutter spoke is bent from the base portion with respect to the cutter rotating shaft 4 toward the outer peripheral edge into a curved shape (arc shape) that is convex on the front side, and the plurality of cutter bits 5, ... are arranged on the front face of the arc-shaped spoke 51 so as to excavate the natural ground along the curved shape. In other words, although the plurality of cutter bits 53, ... have substantially the same length, since the arc-shaped spoke 51 itself is curved in an arc shape, the locus of the tips of the cutter bits 53, ... also becomes an arc shape.

[0018] The arc-shaped spoke 51 has its central end fixed to the cutter rotating shaft 4, extends while curving toward the rear side, and has its outer peripheral end fixed to the linear spoke 52. Furthermore, the linear spoke 52 has its central end fixed to the cutter rotating shaft 4, extends vertically outward, and has its outer peripheral end fixed to the arc-shaped spoke 51. A plurality of cutter bits 53, ... having approximately the same length are provided on the front side of the arc-shaped spoke 51, so that the front side of the cutter bits 53 draws a locus obtained by rotating an arc shape (a spherical locus).

[0019] The cutter head 5 is integrally attached to the cutter rotating shaft 4, and rotates integrally therewith when the cutter rotating shaft 4 rotates. Note that the number of arc-shaped spokes 51 and linear spokes 52 is not limited to four as described herein; for example, the number may be three, or may be five, six or more. The shape of the arc-shaped spoke 51 and the setting method for the cutter bits 53, ... will be described later. Furthermore, an outer peripheral ring (not shown) may be arranged on the outer peripheral portion of the spoke 51.

[0020] Chamber 13 is a space enclosed by the hood of the skin plate 2, the bulkhead 3, and the working face F. A screw conveyor is used as the soil removal device 7. The soil intake port 71 of the soil removal device 7 is opened and installed so as to face the lowest part of the chamber 13. Furthermore, an erector 15 for assembling the segment 90 is installed at the tail of the skin plate 2.

[0021] Multiple shield jacks 8 are installed inside the skin plate 2 at required intervals in the circumferential direction. Each shield jack 8 consists of a piston section and a spreader section. A tail seal 14 is also provided at the rear end of the skin plate 2. In addition, although not shown, a mud injection device (tank, pump, piping) is installed.

[0022] (How to determine the shape of the curve) Next, using Figures 3 and 4, we will explain how to determine the curved shape of the earth pressure balance shield 1 used as a shield tunneling machine in this embodiment—that is, the shape of the arc-shaped spokes 51 and / or the arrangement of the cutter bits 53. The curved shape is determined by FEM analysis based on the theory of the face shape of mountain tunnels, but the initial values ​​for the FEM analysis can be determined, for example, by the following procedure A to C. However, the following procedure is illustrative, and the curved shape is not limited to the method described below.

[0023] A. Set the cutter spoke (51) thickness + chamber (13) thickness to match the excavation area (excavation length). This will be the basis, but the range will be from excavation area (L) to 2L, taking into consideration the manufacturer's track record, etc.

[0024] B. The cutter bit (53) and cutter spoke (51) are positioned to cut the desired spherical shape.

[0025] C. The cutter bit (53) should, in principle, be mounted in the same direction as the thrust direction, however, this does not apply if the bit width is wide and the cutting cross-section does not conform to the desired spherical shape.

[0026] Steps A through C can be explained in more detail as follows: Steps 1) through 5).

[0027] 1) The sphere's center is, for example, located on a straight line (SL) parallel to the position where the shield excavation outer diameter is in a ratio of 2.5:1.0.

[0028] 2) The excavation length (L) shall be, for example, half the width of the segment used in the straight section.

[0029] 3) The head excavation length (Ls) is, for example, twice the excavation length (L) plus a 300 mm margin. This serves as the basic principle, but the face stability and safety are considered and determined through FEM analysis and trial construction.

[0030] 4) The spherical shape is defined as a sphere that passes through point A: the position of 1 excavation length at the top of the excavation, and point B: the mirror excavation length on the SL line.

[0031] 5) Project the upper half of the spherical shape onto the lower half, inverting it from the center line of the outer diameter of the excavation.

[0032] Thus, by following steps 1) to 5), for example, in the case of an excavation outer diameter of 3000 mm, the radius of the spherical face can be determined to be 3290 mm. Similarly, as examples, calculations for the cases of an excavation outer diameter of 6000 mm and an excavation outer diameter of 9000 mm yield the following results. • Excavation outer diameter: 3000 mm; Spherical face radius: 3290 mm (see Figure 4(a)) • Excavation outer diameter: 6000 mm; Spherical face radius: 9330 mm (see Figure 4(b)) • Excavation outer diameter 9000 mm, spherical face radius 16650 mm (see Figure 4(c))

[0033] Then, using the initial values ​​determined in this way, the FEM analysis is actually performed. The ground parameters used in the FEM analysis (internal friction angle φ, cohesion c) are the values ​​obtained from the prior boring survey.

[0034] (Effects / Actions) Next, the functions and effects of the earth pressure balance shield 1 of this embodiment will be listed and explained.

[0035] (1) As described above, the earth pressure balance shield 1 as a shield tunneling machine in this embodiment comprises a rotating cutter rotation shaft 4, cutter spokes 51, 52 extending radially from the cutter rotation shaft 4, and cutter bits 53, ... attached to the front of the cutter spokes 51, 52 for excavating the ground. The cutter bits 53, ... are arranged to excavate the ground along a curved shape that is convex towards the front side, from the base relative to the cutter rotation shaft 4 toward the outer edge. Therefore, the cutter bits 53, ... are arranged to excavate the ground along a curved shape that is convex towards the front side, from the base relative to the cutter rotation shaft 4 toward the outer edge. With such a configuration, even if the condition of the mud or pressure is not sufficient, the face can be stabilized by the ground arch effect of the ground.

[0036] Furthermore, it offers the following advantages: 1) It fits the shape of circular shafts and tunnels when starting from within them. 2) Torque distribution during direct cutting, etc. 3) Improved straight-line movement. 4) Reduced injection volume through effective addition of slurry material. 5) Construction can be completed in a relatively short time and at a low cost.

[0037] (2) Furthermore, the arc-shaped cutter spokes 51, which serve as cutter spokes, are bent into a curved shape (arc shape) with the front side convex from the base to the outer edge relative to the cutter rotation axis 4, so that the cutter bits 53, ... excavate the ground along this curved shape, which increases the capacity of the chamber 13 located behind the arc-shaped cutter spokes 51, making it even easier to plasticize the excavated soil.

[0038] (3) In this case, it is preferable that the earth pressure balance shield 1 further comprises a bulkhead 3, a shield propulsion jack 8, and a soil removal device 7, and that the pressure inside the chamber 13 is adjusted by the propulsion force from the shield propulsion jack 8 and the soil removal device 8. In the case of such an earth pressure balance shield, since there is no face plate, the face is held down by plastically flowed mud, and there is great significance in creating a ground arch effect in the ground by excavating the face in a spherical shape.

[0039] (4) It is preferable that the side of the cutter rotation shaft 4 is provided with high-pressure injection nozzles 41, 41 for injecting the mud-making material into the chamber 13 at high pressure. With such a configuration, the mud in the widened, curved chamber 13 can be efficiently plastically fluidized. In particular, it is possible to prevent the mud from solidifying or rotating together with the center of the dome-shaped cutter head 5. When high-pressure injection is performed in this manner, it is necessary to minimize the impact on the cutting face, and in this embodiment, the spherical shape ensures the capacity of the chamber 13, thereby minimizing the impact on the cutting face. Furthermore, increasing the width of the chamber 13 is advantageous in order to ensure sufficient mixing time.

[0040] (5) Furthermore, a fixed stirring blade 31 is further installed at the lower part of the partition wall 3, and the fixed stirring blade 31 is preferably formed to be rotatable about its axis, and a high-pressure mud-making nozzle 32a for injecting mud-making material into the chamber 13 at high pressure and a high-pressure washing nozzle 32b for injecting abrasive material into the chamber 13 at high pressure are provided on the side of the fixed stirring blade 31. With such a configuration, the mud in the widened, curved chamber 13 can be efficiently plastically fluidized. Furthermore, the compaction of soil near the screw conveyor, which is the soil removal device 7, the earth pressure gauge, and the end of the chamber can be removed.

[0041] Although embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and any design modifications that do not depart from the spirit of the present invention are included in the present invention.

[0042] For example, in the embodiment, the case in which the cutter spoke (arc-shaped spoke) 51 is formed in an arc shape was described, but it is not limited to this, and the cutter spoke (51) itself can be in a straight shape (a shape that traces a conical trajectory), and the arc shape can be formed by the trajectory of the tip of the cutter bit 53.

[0043] For example, although the embodiment described an earth pressure balance shield 1 equipped with high-pressure nozzles 41, 32a, and 32b, the invention is not limited to this, and the cutter head 5 capable of forming the spherical shape of the present invention can also be applied to an earth pressure balance shield 1 without high-pressure nozzles 41, 32a, and 32b.

[0044] Furthermore, while the method for setting the arc shape was explained in detail using Figures 3 and 4 in the embodiment, it is not limited to this, and other curves besides arcs may be used, or even if it is an arc shape, it can be set using various methods other than the method described. [Explanation of Symbols]

[0045] 1: Earth pressure balance shield 2: Skin Plate 3: Bulkhead 4: Cutter rotation axis 5: Cutter head 6: Cutter drive unit 7:Earth removal device 8: Shield propulsion jack 11: Bearings 12: Gearbox 13: Chamber 14: Tail seal 15: Erector 31: Fixed impeller 32a: High-pressure injection nozzle for mud production 32b: High-pressure cleaning nozzle 41: High-pressure injection nozzle for mud production 51: Arc-shaped spokes 52: Straight spokes 53: Cutter Bit 54: Fishtail Bit 55: Agitator blade 56: Copy cutter 60: Rotary drive source 71: Mud intake 90: Segment F: Shutters

Claims

1. A shield tunneling machine having a center shaft support system, an intermediate support system, or an outer perimeter support system, The rotating cutter shaft, The cutter spokes extend radially from the cutter rotation axis, The cutter spoke is equipped with a cutter bit attached to the front surface for excavating the ground, The cutter bit is positioned to excavate the ground along a curved shape that is convex towards the front, extending from the base to the outer edge relative to the cutter rotation axis. The cutter spokes are bent into a curved shape with a convex front end from the base to the outer edge relative to the cutter rotation axis, so that the cutter bit excavates the ground along the curved shape, in a shield tunneling machine.

2. A shield tunneling machine according to claim 1, further comprising a bulkhead, a shield propulsion jack, and a soil removal device, wherein the pressure inside the chamber is adjusted by the propulsion force from the shield propulsion jack and the amount of soil removed by the soil removal device.

3. A shield tunneling machine according to claim 1 or claim 2, wherein a high-pressure mud injection nozzle for injecting mud material into the chamber at high pressure is provided on the side of the cutter rotation shaft.

4. A shield tunneling machine according to claim 1 or claim 2, wherein a fixed stirring blade is further installed at the lower part of the bulkhead, the fixed stirring blade is formed to be rotatable about an axis, and the side surface of the fixed stirring blade is provided with a high-pressure mud-making nozzle for injecting mud-making material into the chamber at high pressure and a high-pressure cleaning nozzle for injecting abrasive material into the chamber at high pressure.

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