Tunnel Boring Machine

Abstract

To appropriately reduce friction between a skin plate and an inner wall surface of the ground.SOLUTION: A tunnel excavator 1 comprises a cylindrical excavator body 10 having a cutter head attached to its front end and a porous covering material 21 which is provided on an outer peripheral surface of a skin plate 10a of the excavator body 10 and is made of porous material, and the porous covering material 21 can hold lubricant (grease G) to reduce friction between the skin plate 10a and an inner wall surface of the ground 2.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a tunnel boring machine.

Background Art

[0002] Generally, a tunnel boring machine excavates a tunnel by rotating a cutter head, and a plurality of cutter bits mounted on the front surface of the cutter head excavate the ground ahead to form a face. The cutter head is attached to the front end of a cylindrical boring machine body, and the tunnel is excavated as the boring machine body is propelled forward.

[0003] Here, when the boring machine body moves forward, the outer peripheral surface of the skin plate of the boring machine body and the inner wall surface of the ground formed by being excavated by the tunnel boring machine come into contact with each other, and friction occurs. The friction between the skin plate and the inner wall surface of the ground becomes a resistance in the propulsion of the tunnel boring machine, and may also be a factor causing an intermittent propulsion operation of the tunnel boring machine (that is, an operation in which the forward movement and stop of the tunnel boring machine are repeated). The instability of the propulsion operation of the tunnel boring machine in this way can also be a factor increasing the vibration transmitted to the ground during tunnel excavation. In addition, the friction between the skin plate and the inner wall surface of the ground can also be a factor deteriorating the energy efficiency in the propulsion operation of the tunnel boring machine.

[0004] Therefore, techniques for reducing the friction between the skin plate and the inner wall surface of the ground have been proposed. For example, Patent Document 1 discloses a technique for reducing the friction between the skin plate and the inner wall surface of the ground by supplying a lubricating liquid from inside the machine to the outer peripheral surface of the skin plate.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, it is considered desirable to more appropriately reduce the friction between the skin plate and the inner wall surface of the ground. For example, in the technique disclosed in Patent Document 1, it may be difficult to retain the lubricating fluid on the outer peripheral surface of the skin plate due to, for example, the lubricating fluid supplied to the outer peripheral surface of the skin plate penetrating into the ground. As a result, a situation may occur in which it is difficult to sufficiently reduce the friction between the skin plate and the inner wall surface of the ground.

[0007] Therefore, in view of such problems, an object of the present invention is to provide a tunnel boring machine capable of appropriately reducing the friction between a skin plate and the inner wall surface of the ground.

Means for Solving the Problems

[0008] To solve the above problems, a tunnel boring machine according to the present invention includes a cylindrical boring machine body having a cutter head attached to the front end, and a porous coating material made of a porous material provided on the outer peripheral surface of the skin plate of the boring machine body. The porous coating material is capable of holding a lubricating fluid for reducing the friction between the skin plate and the inner wall surface of the ground, and includes a low-friction coating material provided on the outer peripheral surface of the skin plate and having a friction coefficient lower than that of the skin plate. The low-friction coating material includes a rear low-friction coating material disposed rearward in the tunnel boring direction of the outer peripheral surface of the skin plate than the porous coating material. See, the rear low-friction coating material includes a plurality of first rear low-friction coating materials and a plurality of second rear low-friction coating materials arranged behind the plurality of first rear low-friction coating materials in the tunnel excavation direction. The plurality of first rear low-friction coating materials and the plurality of second rear low-friction coating materials are each provided at intervals in the circumferential direction of the outer peripheral surface of the skin plate. The circumferential position of the gap between the first rear low-friction coating materials adjacent to each other in the circumferential direction and the circumferential position of the gap between the second rear low-friction coating materials adjacent to each other in the circumferential direction are offset from each other. 。

[0009] The lubricating fluid includes grease, and the tunnel boring machine may include a supply mechanism for supplying grease from inside the machine to the porous coating material.

[0010] The supply mechanism may supply grease to the front-side portion of the porous coating material in the tunnel boring direction.

[0011] The lubricating fluid may include water gushing out from the ground excavated by the tunnel boring machine.

[0012] The porous coating material may have a network-like pore structure composed of a plurality of pores continuous with each other.

[0013] The porous material may be a porous metal.

[0014] The porous material may be a porous ceramic.

[0015] The porous coating material , circumference may extend along the direction.

[0018] The low-friction coating material , circumference may extend along the direction.

Advantages of the Invention

[0019] According to the present invention, it is possible to appropriately reduce the friction between the skin plate and the inner wall surface of the ground.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0021] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. The dimensions, materials, and other specific numerical values shown in such embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same functions and configurations are denoted by the same reference numerals to omit redundant descriptions, and elements not directly related to the present invention are not shown.

[0022] First, with reference to FIG. 1, the overall configuration of the tunnel boring machine 1 according to an embodiment of the present invention will be described. FIG. 1 is a schematic cross-sectional view showing the overall configuration of the tunnel boring machine 1. The arrow D in FIG. 1 indicates the traveling direction of the tunnel boring machine 1. Hereinafter, the traveling direction of the tunnel boring machine 1 (the left direction in FIG. 1) will be described as the forward direction of the tunnel boring direction, and the direction opposite to the traveling direction (the right direction in FIG. 1) will be described as the rear direction of the tunnel boring direction.

[0023] The tunnel boring machine 1 is an earth pressure type (including earth pressure balance type) shield boring machine capable of excavating the ground 2. As shown in FIG. 1, the tunnel boring machine 1 includes a boring machine body 10. The boring machine body 10 has a cylindrical shape (for example, a cylindrical shape or a rectangular cylindrical shape, etc.). The axial direction of the boring machine body 10 coincides with the tunnel boring direction. Hereinafter, the axial direction of the boring machine body 10 will also be simply referred to as the axial direction, the radial direction of the boring machine body 10 will also be simply referred to as the radial direction, and the circumferential direction of the boring machine body 10 will also be simply referred to as the circumferential direction.

[0024] The boring machine body 10 includes a skin plate 10a. The skin plate 10a is a portion that contacts the inner wall surface 2a (the shaft wall) of the ground 2 formed by being excavated by the tunnel boring machine 1 in the boring machine body 10. The skin plate 10a has a cylindrical shape (for example, a cylindrical shape or a rectangular cylindrical shape, etc.) and forms the outer peripheral portion of the boring machine body 10.

[0025] At the front end of the excavator body 10, a cutter head 11 is provided. The cutter head 11 is a substantially disk-shaped rotating body. At the center of the cutter head 11, the front end of a cutter center axis 12 is inserted, and the cutter head 11 is pivotally supported so as to be rotatable about the cutter center axis 12.

[0026] The cutter head 11 has an outer peripheral ring 11a, an inner peripheral ring 11b, cutter spokes 11c, a fishtail cutter 11d, cutter bits 11e, and the like. Among these, the outer peripheral ring 11a forms the outer peripheral portion of the cutter head 11, and the inner peripheral ring 11b is arranged radially inward of the outer peripheral ring 11a. Also, a plurality of cutter spokes 11c are arranged radially about the cutter center axis 12 on the front surface of the cutter head 11. A fishtail cutter 11d is mounted at the center of the front surface of the cutter head 11. Further, a number of cutter bits 11e are mounted on the front surfaces of the cutter spokes 11c. Note that the fishtail cutter 11d and the cutter bits 11e may or may not be detachable.

[0027] And, a plurality of openings are formed between the outer peripheral ring 11a, the inner peripheral ring 11b, and the cutter spokes 11c of the cutter head 11. The openings function as excavation soil intake ports for taking in the excavation soil and sand generated when the cutter head 11 excavates the natural ground 2 (face) into the excavator body 10 (inside a chamber 17 described later).

[0028] Behind the cutter head 11 in the excavator body 10, a partition wall 13 is arranged. The partition wall 13 is a plate-shaped (for example, disk-shaped) wall body arranged perpendicular to the axial direction (tunnel extension direction), and the outer peripheral edge of the partition wall 13 is attached to the inner peripheral surface of the excavator body 10. The cutter head 11 and the partition wall 13 are arranged at a predetermined interval in the axial direction (tunnel extension direction). Various facilities of the tunnel boring machine 1 are arranged on the rear side of the partition wall 13, and the partition wall 13 isolates the facilities from the excavation soil and sand generated at the face. An outlet 13a, which is an opening for discharging the excavation soil and sand, is formed at the lower part of the partition wall 13.

[0029] At the center of the partition wall 13, the cutter center shaft 12 is rotatably supported. Further, on the partition wall 13, an annular rotating ring 14 is rotatably supported about the cutter center shaft 12. At the front of the rotating ring 14, a plurality of connecting beams 15 are provided at predetermined intervals in the circumferential direction. The plurality of connecting beams 15 connect the cutter head 11 and the rotating ring 14. The front end of the connecting beam 15 is connected to the connection portion between the inner circumferential ring 11b of the cutter head 11 and the cutter spoke 11c. On the other hand, a ring gear 14a is provided at the rear of the rotating ring 14. Note that the ring gear 14a may be an external gear type or an internal gear type. Further, a cutter rotation motor 16 is provided behind the partition wall 13. The drive gear 16a of this cutter rotation motor 16 meshes with the ring gear 14a of the rotating ring 14.

[0030] By driving the cutter rotation motor 16, the rotation of its drive gear 16a is transmitted from the ring gear 14a to the rotating ring 14 and the connecting beam 15. Thereby, the cutter head 11 can be rotated about the cutter center shaft 12. As a result, the front surface of the rotating cutter head 11 can be pressed against the natural ground 2 (the face of the tunnel), and the natural ground 2 can be excavated.

[0031] A chamber 17 is defined between the cutter head 11 and the partition wall 13. The chamber 17 is a space (for example, a substantially cylindrical space) defined by the rear surface of the cutter head 11, the front surface of the partition wall 13, and the inner circumferential surface of the excavator body 10. The excavated soil and sand generated along with the excavation of the natural ground 2 by the cutter head 11 is taken into the chamber 17 through the above-mentioned opening (excavated soil and sand intake port) formed through the cutter head 11. The chamber 17 functions as a space (room) for temporarily storing the excavated soil and sand. The excavated soil and sand taken into the chamber 17 is discharged from the chamber 17 into the screw conveyor 18 through the discharge port 13a at the lower part of the partition wall 13.

[0032] The screw conveyor 18 is provided on the rear side of the partition wall 13 within the excavation machine main body 10. The screw conveyor 18 is arranged within the excavation machine main body 10 to be inclined upward as it goes toward the rear side. The opening at the front end of the screw conveyor 18 is connected to the discharge port 13a of the partition wall 13. Thereby, the internal space of the screw conveyor 18 communicates with the chamber 17 through the discharge port 13a of the partition wall 13. Inside the screw conveyor 18, a screw blade 18a, which is a screw-shaped rotating body equipped with spiral blades, is provided. By rotationally driving the screw blade 18a, the excavated earth and sand stored in the chamber 17 can be taken into the screw conveyor 18, transported toward the rear of the excavation machine main body 10, and discharged.

[0033] Also, an erector device (not shown) is provided on the rear side of the partition wall 13 of the excavation machine main body 10. The erector device is provided so as to be movable in the axial direction, radial direction, and circumferential direction (i.e., the tunnel extension direction, tunnel radial direction, and tunnel circumferential direction) of the excavation machine main body 10. The erector device can grip the segment S, which is a lining member, and assemble the gripped segment S along the inner wall surface 2a of the natural ground 2.

[0034] The segment S is an annular piece having a curved shape along the inner wall surface 2a of the excavated natural ground 2. By driving the above-described erector device, a plurality of segments S can be assembled annularly along the circumferential direction. Thereby, the tunnel is lined with a plurality of segments S, and the collapse of the inner wall surface 2a of the natural ground 2 can be prevented.

[0035] Inside the tunneling machine body 10, a plurality of shield jacks 19 are provided at intervals in the circumferential direction. Each shield jack 19 is provided along the inner circumferential surface of the tunneling machine body 10 so as to extend in the tunnel extension direction. The shield jack 19 is, for example, a hydraulic jack, but may be other types of jacks, actuators, etc. as long as it can generate the thrust of the tunnel boring machine 1. At the rear end of the shield jack 19, a telescopic drive rod 19a is provided. The tip of the drive rod 19a faces the front end face of the existing segment S. By extending the drive rod 19a of the shield jack 19 rearward and pressing the segment S, a propulsion reaction force (that is, thrust) can be applied to the tunneling machine body 10. That is, the tunneling machine body 10 can move forward by the thrust generated when the shield jack 19 presses the segment S.

[0036] Note that the tunnel boring machine 1 shown in FIG. 1 is a type of tunnel boring machine in which thrust is transmitted from the front end portion of the shield jack 19 to the tunneling machine body 10, but the tunnel boring machine according to the present invention is not limited to this example. For example, the tunnel boring machine according to the present invention may be a type of tunnel boring machine in which thrust is transmitted from a portion behind the shield jack 19 to the tunneling machine body 10. Note that the tunnel boring machine according to the present invention may be a type of tunnel boring machine having a folding function and in which the front body is pushed and propelled, or may be a type of tunnel boring machine having a folding function and in which the rear body is pushed and propelled. Further, the tunnel boring machine according to the present invention may be a tunnel boring machine in which the driving method of the cutter head 11 is a method other than the intermediate support method in FIG. 1 (for example, a center shaft method, a central axis support method, or an outer peripheral support method, etc.).

[0037] In the tunnel boring machine 1 according to the present embodiment, by devising the skin plate 10a, as will be described later, it is possible to appropriately reduce the friction between the skin plate 10a and the inner wall surface 2a of the natural ground 2. However, in FIG. 1, the detailed illustration of the skin plate 10a is omitted. Hereinafter, with reference to FIGS. 2 and 3, the details of the skin plate 10a will be described.

[0038] FIG. 2 is a schematic view showing the appearance of the skin plate 10a. Specifically, FIG. 2 is a view of the outer peripheral surface of the skin plate 10a as seen from the radially outer side. As shown in FIG. 2, a porous coating material 21 is provided on the outer peripheral surface of the skin plate 10a. The porous coating material 21 is a member made of a porous material and covers the outer peripheral surface of the skin plate 10a.

[0039] In the example of FIG. 2, a plurality of porous coating materials 21 are provided at intervals in the circumferential direction of the outer peripheral surface of the skin plate 10a. Each porous coating material 21 has a substantially constant thickness and is formed in a curved plate shape. Each porous coating material 21 extends along the circumferential direction of the outer peripheral surface of the skin plate 10a. Between each porous coating material 21, the width (the length in the left-right direction in FIG. 2) and the circumferential extension length (the length in the up-down direction in FIG. 2) of the porous coating material 21 are the same. However, there may be a pair of porous coating materials 21 in which at least one of the width and the extension length is different from each other.

[0040] The porous coating material 21 is, for example, a member made of a porous metal and has a network-like pore structure composed of a plurality of pores continuous with each other. The size of the pores of the porous coating material 21 is such that it can prevent the intrusion of solids such as excavated earth and sand into the machine (for example, an inner diameter of 1 mm or less). However, as will be described later, the shape and material of the porous coating material 21 are not limited to this example. The tunnel boring machine 1 is provided with a supply mechanism 22 for supplying grease G from the inside of the machine to the porous coating material 21. The supply mechanism 22 includes supply holes 22a for supplying grease G to each porous coating material 21. The supply holes 22a are provided for each porous coating material 21, respectively. The details of the supply mechanism 22 will be described later.

[0041] As described above, grease G is supplied to the porous coating material 21. The grease G supplied to the porous coating material 21 penetrates and stays in the porous structure of the porous coating material 21 and is held by the porous coating material 21. In this way, the porous coating material 21 can hold the grease G. The grease G corresponds to an example of a lubricating fluid for reducing the friction between the skin plate 10a and the inner wall surface 2a of the ground 2. However, the lubricating fluid may be any liquid substance that exhibits a lubricating action for reducing the friction, and is not limited to the grease G supplied by the supply mechanism 22. The lubricating fluid may be water W gushing out from the ground 2, or may be a mud material or a foam material other than the grease G. In the tunnel boring machine 1, as will be described later, by providing the porous coating material 21 on the outer peripheral surface of the skin plate 10a, it is possible to appropriately reduce the friction between the skin plate 10a and the inner wall surface 2a of the ground 2.

[0042] As shown in FIG. 2, in addition to the porous coating material 21, a low-friction coating material 23 is provided on the outer peripheral surface of the skin plate 10a as a member that covers the outer peripheral surface of the skin plate 10a. The low-friction coating material 23 has a friction coefficient lower than that of the skin plate 10a. The low-friction coating material 23 is provided to more effectively reduce the friction between the skin plate 10a and the inner wall surface 2a of the ground 2. The low-friction coating material 23 is, for example, a steel plate that has been subjected to surface treatment by heat treatment for reducing the friction coefficient or mechanical treatment such as shot peening.

[0043] In the example of FIG. 2, the low-friction coating material 23 includes a front low-friction coating material 23a, a rear low-friction coating material 23b, and a rear low-friction coating material 23c. The front low-friction coating material 23a is a low-friction coating material 23 disposed in front of the porous coating material 21 in the tunnel excavation direction on the outer peripheral surface of the skin plate 10a. On the other hand, the rear low-friction coating materials 23b and 23c are low-friction coating materials 23 disposed behind the porous coating material 21 in the tunnel excavation direction on the outer peripheral surface of the skin plate 10a. The rear low-friction coating material 23b is disposed in front of the rear low-friction coating material 23c in the tunnel excavation direction. Note that, as will be described later, the arrangement of the low-friction coating material 23 is not limited to the example of FIG. 2.

[0044] In the example of FIG. 2, a plurality of front low-friction coating materials 23a are provided at intervals in the circumferential direction on the outer peripheral surface of the skin plate 10a. Each front low-friction coating material 23a has a substantially constant thickness and is formed in a curved plate shape. Each front low-friction coating material 23a extends along the circumferential direction of the outer peripheral surface of the skin plate 10a. Between each front low-friction coating material 23a, the width (the length in the left-right direction in FIG. 2) and the circumferential extension length (the length in the up-down direction in FIG. 2) of the front low-friction coating material 23a are the same. However, there may be a pair of front low-friction coating materials 23a in which at least one of the width and the extension length is different from each other.

[0045] Also, in the example of FIG. 2, a plurality of rear low-friction coating materials 23b are provided at intervals in the circumferential direction on the outer peripheral surface of the skin plate 10a. Each rear low-friction coating material 23b has a substantially constant thickness and is formed in a curved plate shape. Each rear low-friction coating material 23b extends along the circumferential direction of the outer peripheral surface of the skin plate 10a. Between each rear low-friction coating material 23b, the width (the length in the left-right direction in FIG. 2) and the circumferential extension length (the length in the up-down direction in FIG. 2) of the rear low-friction coating material 23b are the same. However, there may be a pair of rear low-friction coating materials 23b in which at least one of the width and the extension length is different from each other.

[0046] In the example of FIG. 2, a plurality of rear low-friction coating materials 23c are provided at intervals in the circumferential direction on the outer peripheral surface of the skin plate 10a. Each rear low-friction coating material 23c has a substantially constant thickness and is formed in a curved plate shape. Each rear low-friction coating material 23c extends along the circumferential direction of the outer peripheral surface of the skin plate 10a. Between each rear low-friction coating material 23c, the width (the length in the left-right direction in FIG. 2) and the circumferential extension length (the length in the up-down direction in FIG. 2) of the rear low-friction coating material 23c are the same. However, there may be a pair of rear low-friction coating materials 23c in which at least one of the width and the extension length is different from each other.

[0047] In the example of FIG. 2, the circumferential extension length of the rear low-friction coating material 23b is different from the circumferential extension length of the rear low-friction coating material 23c. Thereby, the circumferential position of the gap between the rear low-friction coating materials 23b adjacent to each other in the circumferential direction and the circumferential position of the gap between the rear low-friction coating materials 23c adjacent to each other in the circumferential direction can be shifted. Thereby, the grease G flowing out from the porous coating material 21 can easily spread to the rear low-friction coating material 23c through the gap between the rear low-friction coating materials 23b adjacent to each other in the circumferential direction.

[0048] Each low-friction coating material 23 is fixed to the outer peripheral surface of the skin plate 10a by welding or the like, for example.

[0049] FIG. 3 is an enlarged cross-sectional view showing the periphery of the porous coating material 21 of the skin plate 10a. Specifically, FIG. 3 is an enlarged cross-sectional view showing a portion within the region R in FIG. 2. As shown in FIG. 3, a groove 10b is provided on the outer peripheral surface of the skin plate 10a. The groove 10b extends along the circumferential direction of the skin plate 10a. The depth (the length in the up-down direction in FIG. 3) of the groove 10b is substantially the same as the thickness (the length in the up-down direction in FIG. 3) of the porous coating material 21. The width (the length in the left-right direction in FIG. 3) of the groove 10b is substantially the same as the width (the length in the left-right direction in FIG. 3) of the porous coating material 21. The porous coating material 21 is fixed by a fixing member 24 in a state of being fitted into the groove 10b.

[0050] In the example of FIG. 3, two fixing members 24 are provided for each porous coating material 21. The two fixing members 24 are arranged at intervals in the front and rear in the tunnel excavation direction. Each fixing member 24 extends, for example, along the circumferential direction of the skin plate 10a. The front side of the porous coating material 21 is sandwiched between the front fixing member 24 (the left fixing member 24 in FIG. 3) and the bottom surface of the groove 10b. The rear side of the porous coating material 21 is sandwiched between the rear fixing member 24 (the right fixing member 24 in FIG. 3) and the bottom surface of the groove 10b. Each fixing member 24 is fixed to the outer peripheral surface of the skin plate 10a by welding or the like, for example. Note that both circumferential ends of the porous coating material 21 may also be sandwiched between a fixing member 24 (not shown) and the bottom surface of the groove 10b.

[0051] Note that in the example of FIG. 3, the porous coating material 21 is fitted into the groove 10b, but the porous coating material 21 may be installed without providing the groove 10b. For example, the porous coating material 21 may be directly installed on the outer peripheral surface of the skin plate 10a, and such a porous coating material 21 may be fixed by a fixing member 24 or the like. In that case, it is preferable to suppress the contact between the porous coating material 21 and the ground 2 and suppress the wear of the porous coating material 21 by making the thickness of the porous coating material 21 thinner than the thickness of the surrounding low-friction coating material 23. Note that the porous coating material 21 may be installed on the outer peripheral surface of the skin plate 10a using, for example, an adhesive or the like without using the fixing member 24.

[0052] As shown in FIG. 3, the supply mechanism 22 includes, for example, a supply hole 22a, a pump 22b, a grease supply source 22c, and a check valve (backflow prevention valve) 22d. The grease supply source 22c stores grease G. The grease supply source 22c is, for example, a tank that stores the grease G. The grease supply source 22c and the supply hole 22a are connected by a flow path (e.g., a pipe) through which the grease G can flow, and the pump 22b is provided in the flow path. The pump 22b sends out the grease G from the grease supply source 22c toward the supply hole 22a. The supply hole 22a communicates the inside of the machine with the groove 10b. Therefore, the grease G sent from the grease supply source 22c to the supply hole 22a is supplied to the porous coating material 21. The check valve 22d is provided between the pump 22b and the supply hole 22a. Thereby, when the pump 22b is stopped, the backflow of the grease G from the supply hole 22a is prevented. Instead of the check valve 22d, a stopper valve may be provided.

[0053] In the example of FIG. 3, the supply hole 22a is formed to penetrate radially from the inner peripheral surface of the skin plate 10a to the bottom surface of the groove 10b. Further, the supply hole 22a communicates with the front portion of the bottom surface of the groove 10b. Therefore, the grease G sent from the grease supply source 22c to the supply hole 22a is supplied to the front portion of the porous coating material 21 in the tunnel excavation direction. However, the supply mechanism 22 only needs to be able to supply the grease G to the porous coating material 21, and the path of the supply hole 22a is not limited to the example of FIG. 3, as will be described later.

[0054] As described above, the tunnel boring machine 1 according to the present embodiment includes a cylindrical boring machine body 10 having a cutter head 11 attached to the front end, and a porous coating material 21 provided on the outer peripheral surface of the skin plate 10a of the boring machine body 10 and made of a porous material. The porous coating material 21 can hold a lubricant (grease G in the above example) for reducing the friction between the skin plate 10a and the inner wall surface 2a of the ground 2.

[0055] Incidentally, when the tunnel boring machine 1 is being propelled, a load (specifically, an overburden load and a load due to earth pressure) acts on the skin plate 10a from the ground 2, causing friction to occur between the skin plate 10a and the inner wall surface 2a of the ground 2. Here, in the tunnel boring machine 1 according to the present embodiment, a part of the load acting from the ground 2 can be received via the lubricating fluid held in the porous coating material 21. By receiving a part of the load acting from the ground 2 via the lubricating fluid that contributes to reducing the coefficient of friction in this way, compared with the case where all of the load acting from the ground 2 is directly received by the skin plate 10a without using the lubricating fluid, the friction between the skin plate 10a and the inner wall surface 2a of the ground 2 can be reduced.

[0056] Furthermore, the porous coating material 21 can attract the lubricating fluid into the pores by capillary action due to the fine pores forming the porous coating material 21 and hold it for a long time after the attraction. Therefore, it is possible to suppress the lubricating fluid supplied to the porous coating material 21 from penetrating into the ground 2 and dissipating. Furthermore, since the size of the fine pores holding the lubricating fluid is small, it is possible to prevent solid matter such as excavated soil from entering the pores, so that replacement between the lubricating fluid and the solid matter does not occur. Therefore, it is possible to maintain the state of receiving a part of the load acting from the ground 2 via the lubricating fluid that contributes to reducing the coefficient of friction. Thus, the friction between the skin plate 10a and the inner wall surface 2a of the ground 2 can be appropriately reduced. Thereby, the occurrence of the intermittent propulsion operation of the tunnel boring machine 1 (that is, the operation in which the forward movement and stop of the tunnel boring machine are repeated) can be appropriately suppressed, so that the vibration transmitted to the ground 2 during tunnel excavation can be appropriately reduced. Also, since the frictional resistance during the propulsion of the tunnel boring machine 1 can be appropriately reduced, the energy efficiency during the propulsion operation of the tunnel boring machine 1 can also be appropriately improved.

[0057] In particular, in the tunnel boring machine 1 according to the present embodiment, the lubricating fluid contains grease G. The tunnel boring machine 1 is provided with a supply mechanism 22 that supplies grease G from inside the machine to the porous coating material 21. Thereby, even if the grease G held in the porous coating material 21 decreases due to contact with the ground 2, the supply mechanism 22 can replenish the porous coating material 21 with grease G. Therefore, it is possible to more appropriately maintain the state of receiving a part of the load acting from the ground 2 via the grease G that contributes to reducing the friction coefficient.

[0058] In particular, in the tunnel boring machine 1 according to the present embodiment, the supply mechanism 22 supplies grease G to the front portion in the tunnel boring direction of the porous coating material 21. Here, the grease G sent from inside the machine to the outer peripheral surface of the skin plate 10a is likely to move rearward in the tunnel boring direction due to contact between the skin plate 10a and the ground 2 when the tunnel boring machine 1 advances. Therefore, by supplying the grease G to the front portion in the tunnel boring direction of the porous coating material 21, it is possible to easily spread the grease G over the entire porous coating material 21. Therefore, the effect of reducing the friction between the skin plate 10a and the inner wall surface 2a of the ground 2 can be enhanced.

[0059] Note that, as described above, the supply mechanism 22 only needs to be able to supply the grease G to the porous coating material 21, and the path of the supply hole 22a is not limited to the example of FIG. 3. For example, in the example of FIG. 3, the supply hole 22a communicates with the front portion of the bottom surface of the groove 10b. However, the supply hole 22a may communicate with the central or rear portion of the bottom surface of the groove 10b. In this case, the supply mechanism 22 supplies the grease G to the central or rear portion of the porous coating material 21 in the tunnel excavation direction. Further, the supply hole 22a may communicate with the side surface of the groove 10b. Further, the supply hole 22a may be inclined with respect to the radial direction of the skin plate 10a. Further, the supply hole 22a may be curved or bent. No matter what form the supply hole 22a is, as long as the grease G can be supplied to the porous coating material 21, the grease G can be attracted into the pores by the capillary action of the fine pores forming the porous coating material 21 and can be held for a long time after the attraction, so that the effect can be obtained.

[0060] In particular, in the tunnel boring machine 1 according to the present embodiment, the porous coating material 21 has a mesh-like pore structure composed of a plurality of mutually continuous pores. Thereby, it is appropriately realized that the porous coating material 21 absorbs the lubricating fluid by the capillary action of the fine pores forming the porous coating material 21 and holds it for a long time. Therefore, it is possible to appropriately suppress the penetration of the lubricating fluid supplied to the porous coating material 21 into the ground 2, so that a state in which a part of the load acting from the ground 2 is received through the lubricating fluid that contributes to reducing the friction coefficient can be appropriately maintained.

[0061] Note that, as described above, the shape of the porous coating material 21 is not limited to this example. For example, the porous coating material 21 may have a pore structure composed of a plurality of mutually separated pores (for example, a plurality of through holes extending in the thickness direction of the porous coating material 21 and parallel to each other). Also in this case, the porous coating material 21 can absorb the lubricating fluid by the capillary action of the fine pores forming the porous coating material 21 and hold it for a long time.

[0062] In particular, in the tunnel boring machine 1 according to the present embodiment, the porous material forming the porous coating material 21 is a porous metal. Here, since the porous coating material 21 is exposed to the outside of the boring machine body 10, it comes into contact with the ground 2. Therefore, by using a porous metal as the porous material forming the porous coating material 21, the strength of the porous coating material 21 can be ensured, and damage to the porous coating material 21 can be suppressed.

[0063] Note that, as described above, the material of the porous coating material 21 is not limited to this example. For example, the porous material forming the porous coating material 21 may be a porous ceramic. Porous ceramics are more likely to enhance wear resistance compared to porous metals. Therefore, by using porous ceramics as the porous material forming the porous coating material 21, it becomes easier to suppress wear of the porous coating material 21. Also, since porous ceramics are lighter than porous metals, the weight of the porous coating material 21 can be reduced. Note that the material of the porous coating material 21 may be a material other than metals and ceramics (for example, a resin-based material).

[0064] In particular, in the tunnel boring machine 1 according to the present embodiment, the porous coating material 21 extends along the circumferential direction of the outer peripheral surface of the skin plate 10a. Thereby, in the circumferential direction, a wide area of the outer peripheral surface of the skin plate 10a can be covered by the porous coating material 21. Therefore, in a wide area in the circumferential direction, a part of the load acting from the ground 2 can be received via a lubricating fluid that contributes to reducing the friction coefficient, so that the friction between the skin plate 10a and the inner wall surface 2a of the ground 2 can be effectively reduced.

[0065] In particular, the tunnel boring machine 1 according to the present embodiment includes a low-friction coating material 23 provided on the outer peripheral surface of the skin plate 10a and having a friction coefficient lower than that of the skin plate 10a. Thereby, in a portion of the outer peripheral surface of the skin plate 10a where the porous coating material 21 is not provided, a part of the load acting from the ground 2 can be received by the low-friction coating material 23. Therefore, the friction between the skin plate 10a and the inner wall surface 2a of the ground 2 can be more effectively reduced.

[0066] Here, the low-friction coating material 23 is a member that covers the skin plate 10a in a state of protruding outward from the outer peripheral surface of the skin plate 10a. Here, in the situation where the porous coating material 21 is installed, the wear of the skin plate 10a holding the porous coating material 21 induces the wear and damage of the porous coating material 21 at the adjacent position, and as a result, it leads to impairing the function of holding the lubricating fluid by the porous coating material 21. Therefore, by using a member having high wear resistance as the low-friction coating material 23, the wear and damage of the low-friction coating material 23 can be suppressed, and due to the long-term presence of the low-friction coating material 23, the wear and damage of the skin plate 10a can be suppressed, and as a result, it can be connected to preventing the function of holding the lubricating fluid by the porous coating material 21 from being impaired. For example, it is preferable that the low-friction coating material 23 has higher wear resistance than the wear resistance of the skin plate 10a.

[0067] In particular, in the tunnel boring machine 1 according to the present embodiment, after the cutter head 11 excavates the ground 2 (face), the skin plate 10a passes through it. However, as it goes further back from the skin plate 10a, a force that presses the inner wall surface 2a against the skin plate 10a acts, and so-called consolidation is likely to occur. Also, in the rear part of the skin plate 10a, since segment assembly is carried out, internal members such as ribs cannot be arranged, and deformation is more likely to occur than in other parts. Therefore, when subjected to consolidation, the resistance to propulsion may increase. Here, the low-friction coating material 23 includes rear low-friction coating materials 23b and 23c that are arranged further rearward in the tunnel boring direction than the porous coating material 21 on the outer peripheral surface of the skin plate 10a. As described above, the grease G sent from inside the machine to the outer peripheral surface of the skin plate 10a is likely to move rearward in the tunnel boring direction due to the contact between the skin plate 10a and the ground 2 when the tunnel boring machine 1 is propelled. Therefore, the rear low-friction coating materials 23b and 23c arranged further rearward in the tunnel boring direction than the porous coating material 21 are likely to be supplied with the grease G flowing out from the porous coating material 21. Thereby, the friction between the rear low-friction coating materials 23b and 23c and the inner wall surface 2a of the ground 2 is further reduced by the lubricating action of the grease G. As a result, the friction between the skin plate 10a and the inner wall surface 2a of the ground 2 can be more effectively reduced.

[0068] In particular, in the tunnel boring machine 1 according to the present embodiment, the low-friction coating material 23 extends along the circumferential direction of the outer peripheral surface of the skin plate 10a. Thereby, in the circumferential direction, a wide area of the outer peripheral surface of the skin plate 10a can be covered with the low-friction coating material 23. Therefore, in a wide area in the circumferential direction, part of the load acting from the ground 2 can be received by the low-friction coating material 23, so that the friction between the skin plate 10a and the inner wall surface 2a of the ground 2 can be more effectively reduced.

[0069] Note that, as described above, the arrangement of the low-friction coating material 23 is not limited to the example of FIG. 2. For example, in the example of FIG. 2, both the front low-friction coating material 23a and the rear low-friction coating materials 23b and 23c are provided on the outer peripheral surface of the skin plate 10a. However, only one of the front low-friction coating material 23a and the rear low-friction coating materials 23b and 23c may be provided on the outer peripheral surface of the skin plate 10a. Also, the number of the front low-friction coating materials (in the above example, the front low-friction coating material 23a) may be two or more, and the number of the rear low-friction coating materials (in the above example, the rear low-friction coating materials 23b and 23c) may be one or three or more. Further, in the above, an example in which the low-friction coating material 23 is provided on the outer peripheral surface of the skin plate 10a has been described, but the low-friction coating material 23 may not be provided on the outer peripheral surface of the skin plate 10a. In that case, the outer peripheral surface of the skin plate 10a may be covered with the porous coating material 21 over the entire area in the tunnel excavation direction.

[0070] In the above, an example in which the grease G is supplied from the inside of the machine to the porous coating material 21 by the supply mechanism 22 has been described. However, as described above, the lubricating fluid is not limited to the grease G supplied by the supply mechanism 22. Hereinafter, with reference to FIG. 4, a modified example in which a lubricating fluid other than the grease G supplied by the supply mechanism 22 is used will be described.

[0071] FIG. 4 is an enlarged cross-sectional view showing the periphery of the porous coating material 21 of the skin plate 10a in the tunnel boring machine 1A according to the modified example. As shown in FIG. 4, in the tunnel boring machine 1A according to the modified example, it is different from the above-described tunnel boring machine 1 in that the supply mechanism 22 is not provided. Note that since the other points are the same as those of the above-described tunnel boring machine 1, the description thereof is omitted.

[0072] Here, when the tunnel boring machine 1A excavates a tunnel, water W gushes out from the ground 2 excavated by the tunnel boring machine 1A. Then, the water W gushing out from the ground 2 is attracted into the pores of the porous coating material 21 by capillary action due to the fine pores forming the porous coating material 21 and is retained for a long time after the attraction. The water W retained by the porous coating material 21 in this way functions as a lubricating fluid for reducing the friction between the skin plate 10a and the inner wall surface 2a of the ground 2, similar to the grease G described above. That is, in the tunnel boring machine 1A, the porous coating material 21 can retain water W as a lubricating fluid for reducing the friction between the skin plate 10a and the inner wall surface 2a of the ground 2. Note that the water W retained by the porous coating material 21 may contain fine particles.

[0073] As described above, in the tunnel boring machine 1A according to the modified example, the lubricating fluid includes the water W gushing out from the ground 2 excavated by the tunnel boring machine 1A. Thereby, similar to the tunnel boring machine 1 described above, the friction between the skin plate 10a and the inner wall surface 2a of the ground 2 can be appropriately reduced. Note that in the tunnel boring machine 1A according to the modified example, a lubricating fluid such as grease G or a substance with a low friction coefficient such as resin may be pre-filled in the porous coating material 21.

[0074] Also, as shown in FIG. 3, even when the supply mechanism 22 is provided, if the pump 22b is stopped and the check valve 22d functions to prevent backflow, it is also possible to use the water W gushing out from the ground 2 excavated by the tunnel boring machine 1A as a lubricating fluid. Here, when the water W is not suitable as a lubricating fluid, or when the water W does not gush out and the lubricating fluid is insufficient, a response may be made to switch between the two by operating the supply mechanism 22.

[0075] As described above, the preferred embodiments of the present invention have been described with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to the above-described embodiments, and it is needless to say that various modified examples or corrected examples within the scope described in the claims also belong to the technical scope of the present invention.

[0076] For example, in the above description, the earth pressure type (including the muddy earth pressure type) tunnel boring machines 1 and 1A have been described. However, the tunnel boring machine according to the present invention may be of the slurry type.

[0077] Also, for example, in the above description, each component of the tunnel boring machines 1 and 1A has been described with reference to the drawings. However, the dimensions and positional relationships of each component in the drawings are merely examples, and thus the dimensions and positional relationships of each component of the tunnel boring machines 1 and 1A are not limited to the examples shown in the drawings. Further, components may be appropriately added, deleted, or changed with respect to the tunnel boring machines 1 and 1A illustrated in the drawings.

Description of Reference Numerals

[0078] 1 Tunnel boring machine 1A Tunnel boring machine 2 Natural ground 2a Inner wall surface 10 Boring machine body 10a Skin plate 10b Groove 11 Cutter head 11a Outer peripheral ring 11b Inner peripheral ring 11c Cutter spoke 11d Fish tail cutter 11e Cutter bit 12 Cutter central axis 13 Partition wall 13a Discharge port 14 Rotating ring 14a Ring gear 15 Connecting beam 16 Motor for cutter rotation 16a Driving gear 17 Chamber 18 Screw conveyor 18a Screw blade 19 Shield jack 19a Driving rod 21 Porous coating material 22 Supply mechanism 22a Supply hole 22b pump 22c grease supply source 22d check valve 23 low-friction coating material 23a front low-friction coating material 23b rear low-friction coating material 23c rear low-friction coating material 24 fixing member Arrow D Grease G Region R Segment S Water W

Claims

1. A cylindrical excavator body with a cutter head attached to the front end, A porous coating material made of a porous material provided on the outer peripheral surface of the skin plate of the excavator body, Comprising, The porous coating material can hold a lubricating fluid for reducing the friction between the skin plate and the inner wall surface of the ground, A low-friction coating material provided on the outer peripheral surface of the skin plate and having a lower friction coefficient than the friction coefficient of the skin plate is provided, The low-friction coating material includes a rear low-friction coating material disposed behind the porous coating material in the tunnel excavation direction on the outer peripheral surface of the skin plate, The rear low-friction coating material includes a plurality of first rear low-friction coating materials and a plurality of second rear low-friction coating materials disposed behind the plurality of first rear low-friction coating materials in the tunnel excavation direction, The plurality of first rear low-friction coating materials and the plurality of second rear low-friction coating materials are respectively provided at intervals in the circumferential direction of the outer peripheral surface of the skin plate, The circumferential position of the gap between the adjacent first rear low-friction coating materials in the circumferential direction and the circumferential position of the gap between the adjacent second rear low-friction coating materials in the circumferential direction are shifted from each other, Tunnel boring machine.

2. The lubricating fluid includes grease, The tunnel boring machine is provided with a supply mechanism for supplying the grease from inside the machine to the porous coating material, The tunnel boring machine according to claim 1.

3. The supply mechanism supplies the grease to the front portion of the porous coating material in the tunnel excavation direction, The tunnel boring machine according to claim 2.

4. The lubricating fluid includes water gushing out from the ground excavated by the tunnel boring machine, The tunnel boring machine according to claim 1.

5. The porous coating material has a mesh-like pore structure composed of a plurality of mutually continuous pores, The tunnel boring machine according to claim 1.

6. The porous material is a porous metal, The tunnel boring machine according to claim 1.

7. The porous material is a porous ceramic, The tunnel boring machine according to claim 1.

8. The porous coating material extends along the circumferential direction, The tunnel boring machine according to claim 1.

9. The low-friction coating material extends along the circumferential direction, The tunnel boring machine according to claim 1.

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