Tunnel excavation method and tunnel excavator

Abstract

To provide a tunnel excavation method exploring a state of the natural ground in front of a cutter head with accuracy while suppressing time extension required to whole shield work.SOLUTION: A tunnel excavation method includes: an excavation process advancing a tunnel excavator 1 while excavating the natural ground 2 through rotation of a cutter head 11; and an installation process installing segments S for a ring at a rear section of the tunnel excavator 1, the excavation process and the installation process being alternatively or partially parallelly carried out and an exploration process exploring a state of the natural ground 2 are carried out parallelly to the installation process where the cutter head 11 stops rotating, wherein the exploration process comprises steps of boring a boring hole H with a boring drill 20, installing a sensor 40 on a boring drill 20 in a state where the boring drill 20 is positioned inside of the boring hole H, and exploring the state of the natural ground 2 on a basis of a detection result of the sensor 40. A length of the boring hole H is corresponding to a width of the segments S.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a tunnel excavation method and 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. With respect to the forward movement of the boring machine body accompanying this excavation, in the rear part inside the boring machine body, segments, which are structural members of the tunnel, are added to the front end of the existing segments to construct the tunnel.

[0003] In recent years, in shield construction using a tunnel boring machine, minimizing the impact on the ground has been regarded as more important than ever. As a technology for this, a technology for exploring the state of the ground ahead of the cutter head has been proposed. For example, Patent Document 1 discloses a technology in which an oscillation part and a vibration receiving part are provided on a cutter head so as to face forward with a space therebetween, the oscillation part and the vibration receiving part are pressed against the ground ahead of the cutter head, and the state of the ground is explored based on the vibration receiving result of the vibration oscillated from the oscillation part by the vibration receiving part.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, although several techniques for exploring the state of the natural ground in front of the cutter head have been proposed, new proposals are desired. Specifically, a new proposal is desired to enable more accurate exploration of the state of the natural ground. Here, if the time required for exploration increases in order to improve the exploration accuracy of the state of the natural ground, there is a risk that the time required for the entire shield construction will be extended. Therefore, it is desirable to accurately explore the state of the natural ground in front of the cutter head while suppressing an extension of the time required for the entire shield construction.

[0006] Therefore, in view of such problems, an object of the present invention is to provide a tunnel excavation method and a tunnel excavator capable of accurately exploring the state of the natural ground in front of the cutter head while suppressing an extension of the time required for the entire shield construction.

Means for Solving the Problems

[0007] In order to solve the above problems, a tunnel excavation method of the present invention is a tunnel excavation method using a tunnel excavator including a cylindrical excavator body, a cutter head rotatably provided at the front end of the excavator body, and at least two boring drills provided on the excavator body for drilling a boring hole in the natural ground in front of the cutter head, the method including an excavation step of advancing the tunnel excavator while excavating the natural ground by rotation of the cutter head, and an installation step of installing segments for one ring behind the tunnel excavator with excavation by the cutter head and advancement of the tunnel excavator stopped, the excavation step and the installation step being repeatedly performed alternately or partially in parallel, and an exploration step of exploring the state of the natural ground being performed in parallel with the installation step in which rotation of the cutter head is stopped. In the exploration step, a boring hole is drilled by the boring drill, a sensor is installed on the boring drill in a state where the boring drill is positioned inside the boring hole, the state of the natural ground is explored based on a detection result of the sensor, and the length of the boring hole corresponds to the width of the segment.

[0008] The exploration step may be completed even before the installation step is completed.

[0009] The length of the boring hole may be longer than the width of one segment and shorter than the width of two segments.

[0010] The length of the boring hole may be equal to or greater than the width of two segments.

[0011] In the exploration process, the change in the state of the natural ground may be determined based on the comparison result between the detection result of the sensor in the previous exploration process and the detection result of the sensor in the current exploration process.

[0012] The boring drill includes at least one first boring drill and at least one second boring drill. The sensor includes a transmitting unit that transmits an exploration wave and a receiving unit that receives the exploration wave. In the exploration process, the transmitting unit may be installed inside the first boring drill, and the receiving unit may be installed inside the second boring drill. The state of the natural ground may be explored based on the reception result of the exploration wave transmitted from the transmitting unit by the receiving unit.

[0013] In the exploration process, before the transmission and reception of the exploration wave by the transmitting unit and the receiving unit, the inside of the first boring drill and the inside of the second boring drill may be filled with a liquid.

[0014] In the exploration process, the state of the natural ground may be explored based on the reception result using a sound wave as the exploration wave.

[0015] In the exploration process, the state of the natural ground may be two-dimensionally explored based on the reception result using acoustic tomography.

[0016] A plurality of second boring drills may be provided for one first boring drill.

[0017] At least one of the boring directions of the boring drills may be inclined radially outward of the tunnel boring machine as it advances in the forward direction of the tunnel boring machine.

[0018] In order to solve the above problems, a tunnel boring machine of the present invention includes a cylindrical boring machine body, a cutter head rotatably provided at the front end of the boring machine body, and at least two boring drills provided on the boring machine body for drilling a boring hole in the ground in front of the cutter head. The tunnel boring machine is a tunnel boring machine, and includes a boring process of advancing the tunnel boring machine while excavating the ground by rotating the cutter head, and a setting process of installing a segment for one ring behind the tunnel boring machine with the excavation by the cutter head and the advancement of the tunnel boring machine stopped. The processes are alternately or partially parallelly repeated. In parallel with the setting process in which the rotation of the cutter head is stopped, an exploration process of exploring the state of the ground is performed. In the exploration process, a boring hole is drilled by the boring drill, a sensor is installed on the boring drill in a state where the boring drill is located inside the boring hole, and the state of the ground is explored based on the detection result of the sensor. The length of the boring hole corresponds to the width of the segment and is used in the boring process, the setting process, and the exploration process.

Effect of the Invention

[0019] According to the present invention, it is possible to accurately explore the state of the ground in front of the cutter head while suppressing an extension of the time required for the entire shield construction.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

MODE FOR CARRYING OUT THE INVENTION

[0021] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values shown in such embodiments are merely examples for facilitating 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 function and configuration are denoted by the same reference numerals, and redundant description is omitted. Further, elements not directly related to the present invention are not shown.

[0022] First, with reference to FIGS. 1 and 2, the configuration of the tunnel boring machine 1 according to the embodiment of the present invention will be described. FIG. 1 is a cross-sectional schematic view showing the configuration of the tunnel boring machine 1. The arrow T in FIG. 1 indicates the forward direction of the tunnel boring machine 1. Hereinafter, the forward 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 backward direction of the tunnel boring direction.

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

[0024] A cutter head 11 is provided at the front end of the boring machine main body 10. The cutter head 11 is a substantially disc-shaped rotating body. The front end of a cutter central axis 12 is inserted into the central portion of the cutter head 11, and the cutter head 11 is pivotally supported so as to be rotatable about the cutter central axis 12.

[0025] 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 disposed radially inward of the outer peripheral ring 11a. A plurality of cutter spokes 11c are radially arranged on the front surface of the cutter head 11 about the cutter central axis 12. A fishtail cutter 11d is mounted at the central portion of the front surface of the cutter head 11. Further, a large number of cutter bits 11e are mounted on the front surface of the cutter spokes 11c. Note that the fishtail cutter 11d and the cutter bits 11e may or may not be detachable.

[0026] 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 ground is excavated by the cutter head 11 into the boring machine main body 10 (inside a chamber 17 described later).

[0027] 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, disc-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 excavated soil and sand generated at the face. At the lower part of the partition wall 13, a discharge port 13a, which is an opening for discharging the excavated soil and sand, is formed.

[0028] At the center of the partition wall 13, the cutter central axis 12 is rotatably supported. Further, on the partition wall 13, an annular rotating ring 14 is rotatably supported around the cutter central axis 12. At the front part 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 part between the inner peripheral ring 11b and the cutter spoke 11c of the cutter head 11. On the other hand, a ring gear 14a is provided at the rear part 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.

[0029] 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 around the cutter central axis 12. As a result, the front surface of the rotating cutter head 11 can be pressed against the ground 2 (face) in front of the cutter head 11, and the ground 2 can be excavated.

[0030] 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 peripheral surface of the tunneling machine body 10. The excavated soil and sand generated by the excavation of the 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 (chamber) 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.

[0031] The screw conveyor 18 is provided on the rear side of the partition wall 13 within the tunneling machine body 10. The screw conveyor 18 is arranged to be inclined upward as it goes toward the rear side within the tunneling machine body 10. 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. A screw blade 18a, which is a screw-shaped rotating body provided with spiral blades, is provided within the screw conveyor 18. By rotationally driving the screw blade 18a, the excavated soil and sand stored in the chamber 17 can be taken into the screw conveyor 18, transported toward the rear of the tunneling machine body 10, and discharged.

[0032] Also, an erector device (not shown) is provided on the rear side of the partition wall 13 of the tunneling machine body 10. The erector device is provided so as to be movable in the axial direction, radial direction, and circumferential direction of the tunneling machine body 10 (that is, the tunnel extension direction, tunnel radial direction, and tunnel circumferential direction). The erector device can grip the segment S, which is a lining member, and assemble the gripped segment S along the inner wall surface 3 of the ground formed by the excavation by the cutter head 11.

[0033] Segment S is an annular piece having a curved shape along the inner wall surface 3 of the ground. By driving the 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 3 of the ground can be prevented.

[0034] 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 peripheral surface of the tunneling machine body 10 so as to extend in the tunnel extending 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. A telescopic drive rod 19a is provided at the rear end of the shield jack 19. 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.

[0035] 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 advanced, or a type of tunnel boring machine having a folding function and in which the rear body is pushed and advanced. 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.).

[0036] Here, the tunnel boring machine 1 is provided with a boring drill 20 in order to explore the state of the ground 2 in front of the cutter head 11. Specifically, the boring drill 20 includes a first boring drill 21 and a second boring drill 22. Each boring drill 20 is provided on the boring machine main body 10 and drills a boring hole (see the boring hole H in FIG. 6 described later, etc.) in the ground 2 in front of the cutter head 11.

[0037] FIG. 2 is a diagram showing the arrangement of the boring drill 20. Specifically, FIG. 2 is a view of the partition wall 13 of the boring machine main body 10 as seen from the front of the tunnel boring machine 1 (that is, the view seen from the left side of FIG. 1). In FIG. 2, among the components of the tunnel boring machine 1, the illustration of the components other than the partition wall 13 and the boring drill 20 is omitted, and the shape of the partition wall 13 is also simplified. In the examples of FIGS. 1 and 2, as the boring drill 20, one first boring drill 21 and two second boring drills 22 are provided on the partition wall 13.

[0038] As will be described later, a transmitting unit (see the transmitting unit 41 in FIG. 7 described later, etc.) for transmitting a detection wave is installed in the first boring drill 21 in the detection process of exploring the state of the ground 2. As will be described later, a receiving unit (see the receiving unit 42 in FIG. 7 described later, etc.) for receiving a detection wave is installed in the second boring drill 22 in the detection process of exploring the state of the ground 2. The first boring drill 21 is provided in the vertically upper region of the partition wall 13. In the example of FIG. 2, the first boring drill 21 is located directly above the center position of the partition wall 13. The second boring drill 22 is provided in the vertically lower region of the partition wall 13. In the example of FIG. 2, the two second boring drills 22 are arranged symmetrically with respect to the vertical axis passing through the center position of the partition wall 13. However, the arrangement of each boring drill 20 is not limited to the example of FIG. 2. Also, as will be described later, the number of boring drills 20 is not limited to the example of FIG. 2.

[0039] In FIG. 1, a state where each boring drill 20 is stored behind the partition wall 13 (hereinafter also referred to as the stored state) is shown. As will be described later, each boring drill 20 moves forward from the stored state in FIG. 1 and protrudes forward of the cutter head 11, thereby drilling a boring hole in the natural ground 2.

[0040] FIG. 3 is a schematic cross-sectional view showing the boring drill 20 and the surrounding structure. Note that since the configuration of the first boring drill 21 and the configuration of the second boring drill 22 are substantially the same, in FIG. 3, the first boring drill 21 and the second boring drill 22 are shown together. However, the example in FIG. 3 is merely an example, and various modifications may be made to the example in FIG. 3.

[0041] As shown in FIG. 3, each boring drill 20 has a hollow elongated shape (for example, a cylindrical shape). Each boring drill 20 extends in the axial direction of the tunnel boring machine 1 and is movable in the axial direction of the tunnel boring machine 1. When each boring drill 20 moves forward from the stored state, it is inserted into a through hole 13b provided in the partition wall 13.

[0042] A valve 13c capable of opening and closing the through hole 13b is provided in the partition wall 13. In the example of FIG. 3, the through hole 13b is opened by the valve 13c. On the other hand, in the stored state, the through hole 13b is closed by the valve 13c. Thereby, in the stored state, while preventing the excavated earth and sand in the chamber 17 from flowing into the rear side of the partition wall 13, maintenance (for example, replacement, etc.) of each boring drill 20 can be performed. Note that by installing the valve 13c, each boring drill 20 may be detachably attached to the boring machine main body 10.

[0043] Further, a seal member 13d for sealing the space between the partition wall 13 and each boring drill 20 in a liquid-tight manner is provided in the partition wall 13. The seal member 13d is, for example, an O-ring fitted to the outer peripheral surface of each boring drill 20. The seal member 13d can suppress the intrusion of muddy water or the like into the machine through the space between the partition wall 13 and each boring drill 20.

[0044] At the tip of the first boring drill 21 (the left end in Fig. 2), a cutter 21a is provided. Further, a motor 31 is attached to the first boring drill 21. When the motor 31 is driven, rotational power is transmitted from the motor 31 to the first boring drill 21, and the first boring drill 21 rotates about the central axis of the first boring drill 21. By moving the first boring drill 21 in the forward direction of the tunnel boring machine 1 while rotating it, the cutter 21a can insert the first boring drill 21 into the ground 2 while excavating the ground 2. Thereby, a boring hole is formed.

[0045] Similarly, at the tip of the second boring drill 22 (the left end in Fig. 2), a cutter 22a is provided. Further, a motor 32 is attached to the second boring drill 22. When the motor 32 is driven, rotational power is transmitted from the motor 32 to the second boring drill 22, and the second boring drill 22 rotates about the central axis of the second boring drill 22. By moving the second boring drill 22 in the forward direction of the tunnel boring machine 1 while rotating it, the cutter 22a can insert the second boring drill 22 into the ground 2 while excavating the ground 2. Thereby, a boring hole is formed.

[0046] Note that the boring machine main body 10 is provided with a drive mechanism (not shown) for moving each boring drill 20 in the axial direction of the tunnel boring machine 1. Examples of the drive mechanism include a hydraulic jack and the like. By driving the drive mechanism, each boring drill 20 can be moved in the axial direction of the tunnel boring machine 1. Specifically, the first boring drill 21 moves axially integrally with the motor 31, and the second boring drill 22 moves axially integrally with the motor 32.

[0047] At the rear end (the right end in Fig. 2) of the first boring drill 21, a sensor hole 21b is provided. As will be described later, the transmitter 41 is inserted into the first boring drill 21 through the sensor hole 21b. Note that the cable C of the transmitter 41 is inserted through the sensor hole 21b. At the rear end (the right end in Fig. 2) of the second boring drill 22, a sensor hole 22b is provided. As will be described later, the receiver 42 is inserted into the second boring drill 22 through the sensor hole 22b. Note that the cable C of the receiver 42 is inserted through the sensor hole 22b.

[0048] Note that, as will be described later, the transmitter 41 is movable along the axial direction of the first boring drill 21. Therefore, the excavator main body 10 is provided with a device (not shown) for adjusting the position of the transmitter 41.

[0049] Also, at the rear end of the first boring drill 21, an injection hole 21c is provided. As will be described later, liquid is injected into the first boring drill 21 through the injection hole 21c. At the rear end of the second boring drill 22, an injection hole 22c is provided. As will be described later, liquid is injected into the second boring drill 22 through the injection hole 22c.

[0050] As described above, various modifications may be made to the example in Fig. 3. For example, each boring drill 20 may be formed by adding a plurality of pipe members. Thereby, even when it is difficult to secure a large space in the machine, it becomes easier to install each boring drill 20. Also, for example, the portions forming the sensor holes 21b, 22b and the injection holes 21c, 22c may be provided integrally with each boring drill 20 or may be provided detachably.

[0051] Hereinafter, with reference to Figs. 4 to 9, a tunnel excavation method using the tunnel excavator 1 according to the present embodiment will be described.

[0052] In the tunnel excavation method according to this embodiment, for example, an excavation process and an installation process are alternately repeated. However, as will be described later, the excavation process and the installation process may be partially performed in parallel. The excavation process is a process of advancing the tunnel boring machine 1 while excavating the ground 2 by the rotation of the cutter head 11. The installation process is a process of installing the segment S for one ring behind the tunnel boring machine 1 with the excavation by the cutter head 11 and the advancement of the tunnel boring machine 1 stopped. The segment S for one ring is an annular aggregate of a plurality of segments S assembled for one round along the circumferential direction. The width of the aggregate composed of the segment S for one ring (that is, the length of one excavation process of the tunnel boring machine 1) coincides with the width of one segment S.

[0053] Here, in this embodiment, an exploration process is performed in parallel with the installation process in which the rotation of the cutter head 11 is stopped. The exploration process is a process of exploring the state of the ground 2 using the boring drill 20. In this embodiment, by performing the exploration process in parallel with the installation process and further devising the exploration process, as will be described later, it is possible to accurately explore the state of the ground 2 in front of the cutter head 11 while suppressing an extension of the time required for the entire shield construction.

[0054] FIG. 4 is a view showing the state in the excavation process of the tunnel boring machine 1. FIGS. 1 and 4 are views showing the transition of the state of the tunnel boring machine 1 in one excavation process arranged in time series. Specifically, in one excavation process, the state of the tunnel boring machine 1 changes from the state of FIG. 1 to the state of FIG. 4. As described above, the excavation process is a process of advancing the tunnel boring machine 1 while excavating the ground 2 by the rotation of the cutter head 11.

[0055] Figure 4 shows the state of the tunnel boring machine 1 when the excavation process starts from the state shown in Figure 1. As shown in Figure 4, in the excavation process, the cutter rotation motor 16 is driven, and the cutter head 11 is in a rotating state. Then, with the cutter head 11 rotating, the drive rod 19a of the shield jack 19 extends rearward. Thereby, the tip of the drive rod 19a abuts against the front end face of the existing segment S, and the shield jack 19 is in a state of pressing the segment S. In this way, when the shield jack 19 presses the segment S, a propulsion reaction force (that is, thrust) is applied to the boring machine body 10, and the boring machine body 10 moves forward. As a result, the front surface of the rotating cutter head 11 is pressed against the ground 2 in front of the cutter head 11, and the ground 2 is excavated. In one excavation process, the boring machine body 10 moves forward by a length approximately equal to the width of one segment S.

[0056] In the excavation process shown in Figure 4, when the boring machine body 10 has moved forward by a length approximately equal to the width of one segment S as the predetermined length, the extension of the drive rod 19a of the shield jack 19 stops. Then, the cutter rotation motor 16 stops, and the rotation of the cutter head 11 also stops. Thereby, the excavation of the ground 2 by the cutter head 11 ends, and the excavation process ends.

[0057] Figures 5 to 8 are diagrams showing the states of the tunnel boring machine 1 in the installation process and the exploration process. Figures 5 to 8 are diagrams arranging the transitions of the states of the tunnel boring machine 1 in one installation process and one exploration process in time series. Specifically, in one installation process, the state of the tunnel boring machine 1 changes from the state shown in Figure 5 to the state shown in Figure 6, from the state shown in Figure 6 to the state shown in Figure 7, and from the state shown in Figure 7 to the state shown in Figure 8. As described above, the installation process is a process of installing one ring of segments S behind the tunnel boring machine 1 while stopping the excavation by the cutter head 11 and the forward movement of the tunnel boring machine 1.

[0058] In FIG. 5, in a state where the excavation process has been completed, by retracting the shield jack 19 at the portion where the new segment S is to be installed, a state is shown in which a space for assembling the new segment S to the existing segment S is created.

[0059] In FIG. 6, in the space created in the state of FIG. 5, a new segment S is inserted, and the new segment S is installed in front of the existing segment S. This is repeated in order, and the segments S for one ring are installed. The installation of the segment S is performed using an erector device (not shown) as described above. In the installation process, for example, the segments S are installed one by one along the circumferential direction, whereby an aggregate composed of the segments S for one ring is formed.

[0060] Here, in the present embodiment, as described above, the exploration process, which is the process of exploring the state of the natural ground 2, is performed in parallel with the installation process. For example, the exploration process starts at substantially the same timing as the installation process after the excavation process is completed (specifically, temporarily stopped), and is completed at a timing before the installation process is completed. However, the start timing and the completion timing of the exploration process are not limited to the above example. For example, the start timing of the exploration process may be a timing later than the start timing of the installation process. Also, the completion timing of the exploration process may be a timing later than the completion timing of the installation process. Note that there may be a situation where the exploration process is not parallel to the installation process while the excavation process and the installation process are being repeated in a cycle, and such a situation is also included. For example, the implementation of the exploration process during the time of alternation between day shift and night shift, or during the time when the excavation process and the installation process are stopped very briefly on weekends, etc., corresponds to the above case.

[0061] First, as shown in FIG. 6, in the exploration process, a boring hole H is drilled by the boring drill 20. In the example of FIG. 6, the boring hole H is drilled by each of the first boring drill 21 and the second boring drill 22.

[0062] Specifically, the motor 31 is driven, and the first boring drill 21 is in a rotating state. Then, the first boring drill 21 moves in the forward direction of the tunnel boring machine 1 while rotating. Thereby, while the ground 2 is being excavated by the cutter 21a provided at the tip of the first boring drill 21, the first boring drill 21 is inserted into the ground 2. In this way, the boring hole H is drilled by the first boring drill 21.

[0063] Also, the motor 32 is driven, and the second boring drill 22 is in a rotating state. Then, the second boring drill 22 moves in the forward direction of the tunnel boring machine 1 while rotating. Thereby, while the ground 2 is being excavated by the cutter 22a provided at the tip of the second boring drill 22, the second boring drill 22 is inserted into the ground 2. In this way, the boring hole H is drilled by the second boring drill 22.

[0064] In FIG. 6, the length D1 of the segment S (that is, the width of the segment S) in the axial direction of the tunnel boring machine 1 and the length D2 of the boring hole H in the axial direction of the tunnel boring machine 1 are shown. In the present embodiment, the length D2 of the boring hole H is a length corresponding to the width of the segment S (that is, the length D1). Note that the length corresponding to the width of the segment S means a length set according to the width of the segment S and does not have to match the width of the segment S.

[0065] Specifically, the length D2 of the boring hole H is longer than the width of one segment S (that is, the length D1) and shorter than the width of two segments S (that is, the length D1×2).

[0066] Here, as will be described later, the exploration range in the exploration process is basically a range within a length D2 forward from the surface of the natural ground 2 in front of the cutter head 11 in the natural ground 2. Also, as described above, in one excavation process, the excavator body 10 advances by a length approximately equal to the width of one segment S. Therefore, by making the length D2 of the boring hole H longer than the width of one segment S, the state of the range of the natural ground 2 excavated in one excavation process can be explored in the exploration process.

[0067] Also, by making the length D2 of the boring hole H shorter than the width of two segments S, it is possible to effectively suppress the time required for drilling the boring hole H from becoming excessively long (and consequently, the time required for the exploration process from becoming excessively long). Thereby, for example, the exploration process can be completed by the time the installation process is completed, and an increase in the overall time required for the shield construction can be effectively suppressed. As described above, by associating the length D2 of the boring hole H with the width of the segment S, the length D2 of the boring hole H can be, for example, about 3 to 5 m, which can be made shorter compared to, for example, the boring hole H (length about 50 m) performed at the time of arrival of the tunnel boring machine 1 (at the time of joining underground), and thus the time and labor required for drilling can be effectively suppressed.

[0068] However, as will be described later, the length D2 of the boring hole H may be equal to or greater than the width of two segments S (that is, the length D1 × 2).

[0069] Next, as shown in FIG. 7, in the exploration process, with the boring drill 20 positioned inside the boring hole H, the sensor 40 is installed on the boring drill 20. In the example of FIG. 6, as the sensor 40, a transmitting unit 41 and a receiving unit 42 are used. Note that, as will be described later, the type of the sensor 40 installed on the boring drill 20 is not limited to this example.

[0070] Specifically, the transmitting unit 41 transmits sound waves. The receiving unit 42 receives sound waves. Note that the sound waves correspond to an example of the probing waves transmitted from the transmitting unit 41 and received by the receiving unit 42. The probing waves are waves for probing the state of the ground 2. However, the probing waves may be waves other than sound waves (for example, electromagnetic waves, etc.). The transmitting unit 41 and the receiving unit 42 have, for example, an elongated shape (for example, a cylindrical shape). The overall length of the receiving unit 42 (that is, the length in the axial direction) is longer than the overall length of the transmitting unit 41, and a plurality of detectors for receiving and detecting signals may be appropriately arranged within this length.

[0071] The transmitting unit 41 is installed inside the first boring drill 21. For example, the transmitting unit 41 is installed parallel to the first boring drill 21. The transmitting unit 41 is movable along the axial direction of the first boring drill 21 inside the first boring drill 21. The receiving unit 42 is installed inside the second boring drill 22. Specifically, the receiving unit 42 is installed in each of the two second boring drills 22. For example, the receiving unit 42 is installed parallel to the second boring drill 22.

[0072] Here, the transmitting unit 41 is installed inside the first boring drill 21 in a state where the inside of the first boring drill 21 is filled with the liquid L. The receiving unit 42 is installed inside the second boring drill 22 in a state where the inside of the second boring drill 22 is filled with the liquid L. The liquid L is, for example, water. However, the liquid L may be a liquid other than water. As will be described later, the filling of the liquid L into the inside of each boring drill 20 is performed to enable the receiving unit 42 to appropriately receive the sound waves transmitted from the transmitting unit 41.

[0073] The filling of the liquid L into the inside of each boring drill 20 is performed, for example, before the transmitting unit 41 and the receiving unit 42 are installed inside each boring drill 20. For example, as described above, injection holes 21c, 22c (see FIG. 3) for injecting the liquid L are provided at the rear ends of each boring drill 20, and the liquid L is injected into the inside of each boring drill 20 through the injection holes 21c, 22c.

[0074] Then, after each boring drill 20 is filled with the liquid L, the transmitting unit 41 and the receiving unit 42 are respectively installed inside the first boring drill 21 and inside the second boring drill 22. For example, as described above, a sensor hole 21b (see FIG. 3) for inserting the transmitting unit 41 is provided at the rear end of the first boring drill 21, and the transmitting unit 41 is inserted into the first boring drill 21 through the sensor hole 21b. Alternatively, the motor 31 may be removed and the transmitting unit 41 may be inserted through the opening at the rear end of the first boring drill 21. Also, for example, as described above, a sensor hole 22b (see FIG. 3) for inserting the receiving unit 42 is provided at the rear end of the second boring drill 22, and the receiving unit 42 is inserted into the second boring drill 22 through the sensor hole 22b. Alternatively, the motor 32 may be removed and the receiving unit 42 may be inserted through the opening at the rear end of the second boring drill 22.

[0075] However, the filling of the liquid L into each boring drill 20 may be performed after the transmitting unit 41 and the receiving unit 42 are installed inside each boring drill 20. The installation of the transmitting unit 41 and the receiving unit 42 inside each boring drill 20 is performed in advance when the boring hole H is drilled by each boring drill 20, and in that state, the boring hole H may be drilled by each boring drill 20.

[0076] Next, as shown in FIG. 8, in the exploration process, the state of the ground 2 is explored based on the detection result of the sensor 40. In the example of FIG. 8, in the exploration process, sound waves are transmitted from the transmitting unit 41 and received by the receiving unit 42. Then, based on the sound wave reception result by the receiving unit 42, the state of the ground 2 is explored. Hereinafter, an example in which the state of the ground 2 is two-dimensionally explored using acoustic tomography will be described. However, as will be described later, the state of the ground 2 may be explored without using acoustic tomography.

[0077] For example, as shown in FIG. 8, inside the first boring drill 21, the transmitting unit 41 is first located near the tip of the first boring drill 21. The transmitting unit 41 first transmits sound waves at this position. Specifically, the transmitting unit 41 transmits sound waves toward a total of two receiving units 42 respectively installed in each second boring drill 22.

[0078] Each receiving unit 42 receives the sound waves transmitted from the transmitting unit 41. The reception result of the sound waves by the receiving unit 42 reflects the state of the natural ground 2 on the path through which the sound waves pass from the transmitting unit 41 to the receiving unit 42. Therefore, by using the reception result of the sound waves by the receiving unit 42, the state of the natural ground 2 on the path through which the sound waves pass can be explored. Examples of the state of the natural ground 2 that can be explored include, for example, the soil quality, moisture content, presence or absence of voids, size of voids, presence or absence of gravel or foreign substances in the natural ground 2, and the like.

[0079] As described above, the inside of each boring drill 20 is filled with the liquid L. And basically water is also held in the natural ground 2. Therefore, the sound waves transmitted from the transmitting unit 41 reach the receiving unit 42 through the liquid L and the water in the natural ground 2. Thus, for example, a situation where part or all of the sound waves transmitted from the transmitting unit 41 are reflected by the boundary between water and air and do not reach the receiving unit 42 can be suppressed. Therefore, the sound waves transmitted from the transmitting unit 41 can be appropriately received by the receiving unit 42. In particular, in the drilling of the boring hole H, due to the process of taking in earth and sand into the inside of the boring drill 20 or inserting a pipe member into the natural ground 2, air from inside the machine may enter the inside of the boring drill 20, and the properties of the substances inside the boring drill 20 may not be stable. This may hinder highly accurate exploration. Therefore, by filling the inside of the boring drill 20 with the liquid L having stable properties, highly accurate exploration can be performed.

[0080] Here, the sound wave transmitted from the transmitting unit 41 propagates while spreading three-dimensionally. Also, the overall length of the receiving unit 42 is approximately the same as the length D2 of the boring hole H, and the receiving unit 42 extends over substantially the entire area of the boring hole H, and a plurality of detectors for receiving and detecting signals are appropriately arranged within its length. Therefore, the receiving unit 42 can receive the sound wave transmitted from the transmitting unit 41 over substantially the entire area of the boring hole H. However, the overall length of the receiving unit 42 may be shorter or longer than the length D2 of the boring hole H. Also, the ratio of the boring hole H within the range where the receiving unit 42 extends within the boring hole H is not particularly limited.

[0081] The transmitting unit 41 moves backward inside the first boring drill 21 while transmitting a sound wave from the position shown in FIG. 8. Therefore, the transmission position of the sound wave changes in the axial direction of the tunnel boring machine 1 over time. Even during this period, the receiving unit 42 continues to receive the sound wave. Therefore, the receiving unit 42 can receive the sound wave that has passed through various paths in the ground 2 in front of the cutter head 11. Thus, the state in a wide range in front of the cutter head 11 can be explored. In the above example, the overall length of the receiving unit 42 is configured to be long, but the receiving unit 42 can be made short like the transmitting unit 41, and the receiving unit 42 can be moved in the axial direction (changed in position) to transmit the sound wave from the transmitting unit 41 to the receiving unit 42 each time, thereby exploring the ground 2.

[0082] FIG. 9 is a diagram showing the exploration range in the exploration process. As described above, by moving the transmitting unit 41 while the sound wave is being transmitted from the transmitting unit 41, various paths in the natural ground 2 in front of the cutter head 11 are included in the exploration range by a pair of one transmitting unit 41 and one receiving unit 42. As a result, as shown in FIG. 9, an exploration plane P that connects the first boring drill 21 and each second boring drill 22 in the natural ground 2 in front of the cutter head 11 becomes the exploration range. And since the state of the exploration plane P in the natural ground 2 can be explored, the state of the natural ground 2 can be explored two-dimensionally. In this way, the method of two-dimensionally exploring the state of the natural ground 2 by using the reception result of the receiving unit 42 obtained while moving the transmitting unit 41 that transmits the sound wave is also called acoustic tomography. Note that two-dimensionally exploring means exploring a planar range that spreads two-dimensionally.

[0083] Specifically, as shown in FIG. 9, an exploration plane P that connects the first boring drill 21 and one second boring drill 22, and an exploration plane P that connects the first boring drill 21 and the other second boring drill 22 become the exploration range. The exploration plane P corresponds to a portion between the first boring drill 21 and the second boring drill 22 among the planes including the first boring drill 21 and the second boring drill 22. In this way, since a plurality of second boring drills 22 are provided for one first boring drill 21, a plurality of exploration planes P can be made the exploration range, so that the state in a wider range in the natural ground 2 can be explored.

[0084] As described above, in the exploration process, the state of the natural ground 2 is explored based on the reception result of the sound wave by the receiving unit 42. The exploration result of the state of the natural ground 2 is used, for example, in the next excavation process. For example, depending on the state of the geology, moisture content, presence or absence of voids, size of voids, etc. in the natural ground 2 within the next excavation range, after setting the excavation conditions (for example, the rotation speed of the cutter head 11, the propulsion force of the tunnel boring machine 1, the forward speed of the tunnel boring machine 1, etc.), the next excavation process is performed. Therefore, the natural ground 2 can be appropriately excavated according to the state of the natural ground 2.

[0085] In the exploration process, the state of the ground 2 can be explored by analyzing in detail the result of receiving sound waves by the receiving unit 42 in this exploration process. For example, a large amount of data in which the result of receiving sound waves in the past is associated with the state of the ground 2 when the result of receiving the sound waves was obtained may be accumulated, and machine learning using such a data group as teacher data may be used to explore the state of the ground 2. Thereby, the state of the ground 2 can be explored accurately in a short time.

[0086] Here, in the exploration process, the change in the state of the ground 2 may be determined based on the comparison result between the result of receiving sound waves by the receiving unit 42 in the previous exploration process and the result of receiving sound waves by the receiving unit 42 in this exploration process. For example, the result of receiving sound waves by the receiving unit 42 in the previous exploration process is compared with the result of receiving sound waves by the receiving unit 42 in this exploration process. If there is no significant difference between the two received results, it can be determined that almost no change in the state of the ground 2 has occurred. On the other hand, if there is a significant difference between the two received results, it can be determined that a change in the state of the ground 2 has occurred. Thereby, it is possible to determine in a short time whether it is necessary to change the excavation conditions.

[0087] When the exploration process is completed, each boring drill 20 moves backward and is withdrawn from the boring hole H, and returns to the stored state shown in FIG. 1. After that, after the installation process is completed, the next excavation process is performed.

[0088] In the above description, an example in which the excavation process and the installation process are alternately repeated has been explained. However, the excavation process and the installation process may be partially performed in parallel. For example, the installation process may start before the excavation process is completed. This is because when the state of the shield jack 19 in the excavation process is up to the completion of excavation, in creating a space for segment installation by retracting the drive rod 19a of the shield jack 19, the amount of retraction of the drive rod 19a (that is, the stroke of the shield jack 19) has a margin with respect to the width D1 of the segment S so that the installation of the segment S becomes easy (see Fig. 6). On the other hand, in the excavation process, from the viewpoint of the space for segment installation, although the margin becomes smaller in the state before the completion of excavation, when a space (a space into which the width D1 of the segment S can fit) where the segment S can be installed is secured, the installation process of the segment S is started, and by performing the excavation process and the installation process partially in parallel, the total construction time of the excavation process and the installation process combined is shortened.

[0089] In the above description, an example in which the transmitter 41 and the receiver 42 are used as the sensor 40 installed in the boring drill 20 has been explained. However, the type of the sensor 40 installed in the boring drill 20 is not limited to the above example. For example, the sensor 40 installed in the boring drill 20 may be a sensor that does not use an exploration wave (for example, a sensor related to current or voltage). Also, for example, only the transmitter 41 may be installed in the boring drill 20. In that case, for example, the receiver 42 is provided in a part of the excavator main body 10 other than the boring drill 20 (for example, the partition wall 13, the cutter head 11, the outer surface of the excavator main body 10, etc.). Then, the state of the ground 2 is explored based on the reception result of the exploration wave transmitted from the transmitter 41 by the receiver 42. Conversely, only the receiver 42 may be installed in the boring drill 20, and the transmitter 41 may be provided in a part other than the boring drill 20.

[0090] Further, in the above description, an example in which one first boring drill 21 and two second boring drills 22 are provided in the partition wall 13 as the boring drill 20 has been described. However, the number of boring drills 20 is not limited to the above example. For example, the number of boring drills 20 may be only one. Also, for example, when the first boring drill 21 and the second boring drill 22 are provided in the partition wall 13, the number of first boring drills 21 may be plural, and the number of second boring drills 22 may be singular or three or more.

[0091] As described above, the tunnel excavation method according to the present embodiment includes an excavation step of advancing the tunnel boring machine 1 while excavating the ground 2 by the rotation of the cutter head 11, and an installation step of installing the segment S for one ring behind the tunnel boring machine 1 in a state where the excavation by the cutter head 11 and the advancement of the tunnel boring machine 1 are stopped. Then, the excavation step and the installation step are repeatedly performed alternately or partially in parallel.

[0092] Also, in the tunnel excavation method according to the present embodiment, a exploration step of exploring the state of the ground 2 is performed in parallel with the installation step in which the rotation of the cutter head 11 is stopped. Then, in the exploration step, a boring hole H is drilled by the boring drill 20, and the sensor 40 (in the above example, the transmitting unit 41 and the receiving unit 42) is installed in the boring drill 20 in a state where the boring drill 20 is located inside the boring hole H, and the state of the ground 2 is explored based on the detection result of the sensor 40. Thereby, since the information reflecting the state of the ground 2 around the sensor 40 can be appropriately detected by the sensor 40 located inside the ground 2 in front of the cutter head 11, the state of the ground 2 in front of the cutter head 11 can be accurately explored.

[0093] Here, the length D2 of the boring hole H corresponds to the width of the segment S (that is, the length D1). Thereby, it is possible to suppress the time required for drilling the boring hole H from becoming excessively long, so that it is possible to suppress the time required for the exploration process, which is carried out in parallel with the installation process, from becoming excessively long, and it is possible to suppress an extension of the time required for the entire shield construction.

[0094] As described above, according to the present embodiment, it is possible to accurately explore the state of the natural ground 2 in front of the cutter head 11 while suppressing an extension of the time required for the entire shield construction. For example, in the method of exploring the state of the natural ground by pressing the transmitting unit 41 and the receiving unit 42 provided on the cutter head 11 against the natural ground as in Patent Document 1 described above, only the vicinity of the face is explored. Further, for example, there is a case where the transmitting unit 41 and the receiving unit 42 provided in the excavator main body 10, the cutter head 11, etc. are integrated, but this is not to directly receive the exploration wave transmitted from the transmitting unit 41, but to receive the reflected wave for exploration. Therefore, the directionality and the signal intensity become unstable in reflection, and as a result, the reflected wave becomes an unstable waveform, so that the exploration accuracy decreases. According to the present embodiment, the exploration accuracy can be improved as compared with these methods.

[0095] In particular, in the tunnel excavation method according to the present embodiment, the exploration process is completed before the installation process is completed. Thereby, it is possible to suppress an increase in the time required for the entire shield construction due to adding the exploration process to the excavation process and the installation process, so that it is possible to effectively suppress an extension of the time required for the entire shield construction.

[0096] In particular, in the tunnel excavation method according to the present embodiment, the length of the boring hole H is longer than the width of one segment S (that is, the length D1) and shorter than the width of two segments S (that is, the length D1×2). Thereby, it is possible to effectively suppress the time required for drilling the boring hole H from becoming excessively long (and thus the time required for the exploration process from becoming excessively long), so that, for example, the exploration process can be completed before the installation process is completed, and it is possible to effectively suppress an extension of the time required for the entire shield construction.

[0097] However, the length D2 of the boring hole H may be equal to or greater than the width of two segments S (that is, the length D1 × 2). Thereby, it is possible to explore the state of the portion of the natural ground 2 that is distant from the surface of the natural ground 2 in front of the cutter head 11. Here, the state of the portion near the surface of the natural ground 2 in front of the cutter head 11 in the natural ground 2 may be disturbed by the excavation by the cutter head 11. Therefore, by exploring the state of the portion of the natural ground 2 that is distant from the surface of the natural ground 2 in front of the cutter head 11, the accuracy of the exploration can be further improved.

[0098] In particular, in the tunnel excavation method according to the present embodiment, in the exploration process, based on the comparison result between the detection result of the sensor 40 in the previous exploration process (in the above example, the reception result of the sound wave by the receiving unit 42) and the detection result of the sensor 40 in the current exploration process, the change in the state of the natural ground 2 is determined. Thereby, it is possible to determine whether or not it is necessary to change the excavation conditions in a short time.

[0099] In particular, in the tunnel excavation method according to the present embodiment, the boring drill 20 includes at least one first boring drill 21 and at least one second boring drill 22. Further, the sensor 40 includes a transmitting unit 41 that transmits an exploration wave (in the above example, a sound wave) and a receiving unit 42 that receives the exploration wave. Then, in the exploration process, the transmitting unit 41 is installed inside the first boring drill 21, the receiving unit 42 is installed inside the second boring drill 22, and the state of the natural ground 2 is explored based on the reception result of the exploration wave transmitted from the transmitting unit 41 by the receiving unit 42. Thereby, the information reflecting the state in a wide range in the natural ground 2 in front of the cutter head 11 can be appropriately detected by the transmitting unit 41 and the receiving unit 42 located inside the natural ground 2 in front of the cutter head 11, so that the state of the natural ground 2 in front of the cutter head 11 can be explored with higher accuracy.

[0100] In particular, in the tunnel excavation method according to the present embodiment, in the exploration process, before the transmission and reception of the exploration wave by the transmission unit 41 and the reception unit 42, the inside of the first boring drill 21 and the inside of the second boring drill 22 are filled with the liquid L. Thereby, the exploration wave transmitted from the transmission unit 41 can reach the reception unit 42 through the liquid L and the water in the ground 2, and can be appropriately received by the reception unit 42.

[0101] In particular, in the tunnel excavation method according to the present embodiment, in the exploration process, sound waves are used as the exploration wave, and the state of the ground 2 is explored based on the reception result of the sound wave by the reception unit 42. Thereby, since information reflecting the state in a wide range in the ground 2 in front of the cutter head 11 is appropriately detected, the state of the ground 2 in front of the cutter head 11 can be explored more accurately.

[0102] In particular, in the tunnel excavation method according to the present embodiment, in the exploration process, acoustic tomography is used to two-dimensionally explore the state of the ground 2 based on the reception result of the sound wave by the reception unit 42. Thereby, the state of the ground 2 in front of the cutter head 11 can be explored with the exploration surface P connecting the first boring drill 21 and the second boring drill 22 as the exploration range. Therefore, the state in a wider range in the ground 2 in front of the cutter head 11 can be explored.

[0103] However, in the exploration process, the state of the ground 2 may be explored without using acoustic tomography. For example, for the above example, by making changes such as transmitting sound waves from the transmission unit 41 without changing the position of the transmission unit 41, the exploration range in the exploration process may be substantially linear.

[0104] In particular, in the tunnel excavation method according to the present embodiment, a plurality of second boring drills 22 are provided for one first boring drill 21. Thereby, the exploration range in the exploration process can be expanded. For example, in the above example, since a plurality of exploration surfaces P can be used as the exploration range, the state in a wider range in the ground 2 can be explored.

[0105] FIG. 10 is a view showing the state in the installation process and the exploration process of the tunnel boring machine 1A according to the modified example. Specifically, FIG. 10 shows, similarly to FIG. 8, a state in which transmission and reception of exploration waves by the transmitter 41 and the receiver 42 are being performed in the exploration process that is carried out in parallel with the installation process. In the tunnel boring machine 1A according to the modified example, the drilling directions of the respective boring drills 20 are different as compared with the above-described tunnel boring machine 1.

[0106] In the above-described tunnel boring machine 1, each boring drill 20 extends in the axial direction of the tunnel boring machine 1 and is movable in the axial direction of the tunnel boring machine 1. That is, in the above-described tunnel boring machine 1, the drilling direction of each boring drill 20 coincides with the forward direction of the tunnel boring machine 1.

[0107] On the other hand, as shown in FIG. 10, in the tunnel boring machine 1A according to the modified example, the drilling direction of each boring drill 20 is inclined radially outward of the tunnel boring machine 1A as it advances in the forward direction of the tunnel boring machine 1A. That is, in the tunnel boring machine 1A according to the modified example, each boring drill 20 extends in a direction inclined with respect to the axial direction of the tunnel boring machine 1 and is movable in that direction. For example, also in the modified example, similar to the above-described example, the state of the ground 2 is explored using the reception result of the receiver 42 obtained while moving the transmitter 41 backward inside the first boring drill 21.

[0108] In the example of FIG. 10, the drilling directions of all the boring drills 20 are inclined radially outward of the tunnel boring machine 1A as it advances in the forward direction of the tunnel boring machine 1A. However, the drilling directions of some of the boring drills 20 may be inclined radially outward of the tunnel boring machine 1A as it advances in the forward direction of the tunnel boring machine 1A, and the drilling directions of some other boring drills 20 may coincide with the forward direction of the tunnel boring machine 1.

[0109] As described above, in the tunnel excavation method using the tunnel boring machine 1A according to the modified example, at least one of the drilling directions of the boring drills 20 is inclined radially outward of the tunnel boring machine 1A as it advances in the forward direction of the tunnel boring machine 1A. Thereby, since the exploration surface P connecting the first boring drill 21 and the second boring drill 22 can be expanded in the radial direction of the tunnel boring machine 1A, the state in a wider range in the natural ground 2 in front of the cutter head 11 can be explored.

[0110] 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 various modifications or correction examples within the scope described in the claims also belong to the technical scope of the present invention.

[0111] 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.

[0112] 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, since the dimensions and positional relationships of the components in the drawings are merely examples, the dimensions and positional relationships of the components of the tunnel boring machines 1 and 1A are not limited to the examples shown in the drawings. Also, components may be appropriately added, deleted, or changed with respect to the tunnel boring machines 1 and 1A illustrated in the drawings.

Explanation of Reference Numerals

[0113] 1 Tunnel boring machine 1A Tunnel boring machine 2 Natural ground 3 Inner wall surface 10 Boring machine main body 11 Cutter head 12 Cutter center axis 13 Partition wall 14 Rotating ring 15 Connecting beam 16 Motor for cutter rotation 17 Chambers 18 Screw conveyor 19 Shield jack 20 Drilling rig 21 First drilling rig 21a Cutter 21b Sensor hole 21c Injection hole 22 Second drilling rig 22a Cutter 22b Sensor hole 22c Injection hole 31 Motor 32 Motor 40 Sensor 41 Transmitter 42 Receiver H Boring hole L Liquid P Exploration surface S Segment

Claims

1. A cylindrical excavation machine body, A cutter head rotatably provided at the front end of the excavation machine body, At least two boring drills provided on the excavation machine body for drilling a boring hole in the ground in front of the cutter head, A tunnel excavation method using a tunnel boring machine comprising: An excavation step of advancing the tunnel boring machine while excavating the ground by rotation of the cutter head, An installation step of installing one ring of segments behind the tunnel boring machine with excavation by the cutter head and advancement of the tunnel boring machine stopped, Including, The excavation step and the installation step are repeatedly performed alternately or partially in parallel, A exploration step of exploring the state of the ground is performed in parallel with the installation step in which the rotation of the cutter head has stopped, In the exploration step, Drilling the boring hole with the boring drill, Installing a sensor on the boring drill with the boring drill positioned inside the boring hole, and exploring the state of the ground based on the detection result of the sensor, The length of the boring hole corresponds to the width of the segment, Tunnel excavation method.

2. The exploration step is completed before the installation step is completed, The tunnel excavation method according to Claim 1.

3. The length of the boring hole is longer than the width of one segment and shorter than the width of two segments, The tunnel excavation method according to Claim 1.

4. The length of the boring hole is equal to or greater than the width of two segments, The tunnel excavation method according to Claim 1.

5. In the exploration step, based on the comparison result between the detection result of the sensor in the previous exploration step and the detection result of the sensor in the current exploration step, the change in the state of the ground is determined, The tunnel excavation method according to Claim 1.

6. The boring drill includes at least one first boring drill and at least one second boring drill, The sensor includes a transmitting unit that transmits an exploration wave and a receiving unit that receives the exploration wave, In the exploration process, the transmitting unit is installed inside the first boring drill, the receiving unit is installed inside the second boring drill, and the state of the ground is explored based on the reception result of the exploration wave transmitted from the transmitting unit by the receiving unit. The tunnel excavation method according to any one of claims 1 to 5.

7. In the exploration process, before the transmission and reception of the exploration wave by the transmitting unit and the receiving unit, the inside of the first boring drill and the inside of the second boring drill are filled with liquid. The tunnel excavation method according to claim 6.

8. In the exploration process, using sound waves as the exploration wave, the state of the ground is explored based on the reception result. The tunnel excavation method according to claim 6.

9. In the exploration process, using acoustic tomography, the state of the ground is explored two-dimensionally based on the reception result. The tunnel excavation method according to claim 8.

10. A plurality of the second boring drills are provided for one of the first boring drills. The tunnel excavation method according to claim 6.

11. At least one of the boring directions of the boring drills is inclined radially outward of the tunnel boring machine as the tunnel boring machine advances. The tunnel excavation method according to claim 6.

12. A cylindrical excavation machine body; A cutter head rotatably provided at the front end of the excavation machine body; At least two boring drills provided on the excavation machine body for drilling boring holes in the ground in front of the cutter head; A tunnel boring machine comprising: An excavation process of advancing the tunnel boring machine while excavating the ground by rotation of the cutter head, and an installation process of installing one ring of segments behind the tunnel boring machine with the excavation by the cutter head and the advancement of the tunnel boring machine stopped are repeatedly performed alternately or partially in parallel. In parallel with the installation process in which the rotation of the cutter head is stopped, an exploration process of exploring the state of the ground is performed. In the exploration process, The boring drill drills the boring hole. With the boring drill positioned inside the boring hole, a sensor is installed on the boring drill, and the state of the ground is explored based on the detection result of the sensor. The length of the boring hole corresponds to the width of the segment. A tunnel boring machine used for the excavation process, the installation process, and the exploration process. ​

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