Tunnel excavation method

Abstract

This tunnel excavation method for forming a lattice-like tunnel including an outer peripheral tunnel, a drift tunnel provided inside the outer peripheral tunnel, and a cross-cut tunnel provided so as to intersect the drift tunnel inside the outer peripheral tunnel using an excavator comprises excavating an excavation object in a first direction and a second direction intersecting the first direction through use of an excavator to form a part of the outer peripheral tunnel, and excavating the excavation object so as to reach an existing tunnel comprising a part of the formed outer peripheral tunnel to form at least one of the drift tunnel and the cross-cut tunnel.

Description

Tunnel Excavation Method

[0001] The present disclosure relates to a tunnel excavation method.

[0002] As an underground mining method, the block caving method as disclosed in Patent Document 1 is known.

[0003] International Publication No. 2015 / 151583

[0004] When mining ore using the block caving method, a lattice tunnel is formed in rock using an excavator. The excavator moves forward while excavating the rock so as to form a portion of the lattice tunnel. The excavator then retreats along the tunnel just formed, and then moves forward again while excavating the rock so as to form another portion of the lattice tunnel. The excavator forms the lattice tunnel by repeatedly moving forward and backward. If the work procedures when forming the lattice tunnel are inappropriate, the workability of the tunnel excavation may be reduced.

[0005] The present disclosure aims to suppress a decline in workability in tunnel excavation.

[0006] According to the present disclosure, there is provided a tunnel excavation method for using an excavating machine to form a lattice tunnel including a perimeter tunnel, a drift tunnel provided inside the perimeter tunnel, and a cross-cut tunnel provided inside the perimeter tunnel so as to intersect with the drift tunnel, the tunnel excavation method including: excavating an excavation target with the excavating machine in a first direction and a second direction intersecting the first direction to form a part of the perimeter tunnel; and excavating the excavation target so as to reach an existing tunnel consisting of a part of the formed perimeter tunnel, to form at least one of the drift tunnel and the cross-cut tunnel.

[0007] According to the present disclosure, the deterioration of workability in tunnel excavation is suppressed.

[0008] FIG. 1 is a top view schematically showing an excavator according to an embodiment. FIG. 2 is a perspective view schematically showing a cutterhead according to an embodiment. FIG. 3 is a diagram schematically showing a reinforced tunnel according to an embodiment. FIG. 4 is a diagram schematically showing a lattice tunnel according to an embodiment. FIG. 5 is a block diagram showing a work procedure generation device according to an embodiment. FIG. 6 is a diagram for explaining a work procedure when forming a lattice tunnel according to an embodiment. FIG. 7 is a diagram for explaining a work procedure when forming a lattice tunnel according to an embodiment. FIG. 8 is a perspective view schematically showing a state in which a second cross cut is connected to a first portion according to an embodiment. FIG. 9 is a diagram schematically showing a state in which a second cross cut is connected to a first portion according to an embodiment. FIG. 10 is a diagram for explaining a work procedure when forming a lattice tunnel according to an embodiment. FIG. 11 is a diagram schematically showing a state in which a new tunnel is not connected to an existing tunnel. FIG. 12 is a diagram for explaining a work procedure when forming a lattice tunnel according to an embodiment.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings, but the present disclosure is not limited to the embodiments. The components of the embodiments described below can be combined as appropriate. In addition, some components may not be used.

[0010] [Excavator] Fig. 1 is a top view schematically showing an excavator 1 according to an embodiment. The excavator 1 is a tunnel boring machine (TBM). The excavator 1 excavates an excavation target in order to form a tunnel. In the embodiment, the excavator 1 excavates a rock mass as the excavation target in order to form a tunnel underground. The excavator 1 can form a tunnel underground by moving forward while excavating the rock mass.

[0011] As shown in Fig. 1 , the excavator 1 includes a forward section 2, a rear section 3, a thrust jack 4, and a trailer section 5. The forward section 2 includes a forward body 6, a cutter head 7, and a forward gripper 8. The rear section 3 includes a rear body 13 and a rear gripper 14. The trailer section 5 includes a main beam 15 and a trailing bogie 16.

[0012] 2 is a perspective view schematically showing the cutter head 7 according to the embodiment. The cutter head 7 is disposed at the front end of the excavator 1. The cutter head 7 is rotatably supported by the front body 6. The cutter head 7 rotates about a central axis CX of the forward section 2. The central axis CX extends in the fore-and-aft direction of the forward section 2. The central axis CX passes through the center of the cutter head 7.

[0013] The cutter head 7 has a cutter body 9 , a disk cutter 10 supported by the cutter body 9 , an outer plate 11 arranged on the periphery of the cutter body 9 , and a scraper 12 arranged on the periphery of the cutter body 9 .

[0014] The cutter body 9 is substantially disk-shaped. The cutter body 9 is rotatably supported by the front body 6. A rotary motor (not shown) connected to the cutter body 9 is disposed in the front body 6. The cutter body 9 rotates about the central axis CX by the rotational force generated by the rotary motor.

[0015] The disc cutter 10 excavates the rock face. The disc cutter 10 is supported by the cutter body 9. A plurality of disc cutters 10 are provided on the cutter body 9. The cutter body 9 rotates about the rotation axis CX, causing the plurality of disc cutters 10 to excavate the rock face.

[0016] The outer plate 11 prevents the rock material crushed by the disc cutter 10 from being transferred from the periphery of the cutter head 7 to the rear of the cutter head 7. The outer plate 11 is annular. The outer plate 11 is fixed to the periphery of the cutter body 9. In the radial direction of the central axis CX, the outer plate 11 protrudes outward beyond the outer end of the cutter body 9. The outer plate 11 is detachable from the cutter body 9.

[0017] The scraper 12 picks up the crushed rock material crushed by the disc cutter 10. A plurality of scrapers 12 are arranged at intervals around the periphery of the cutter body 9. The scrapers 12 are fixed to the periphery of the cutter body 9. In the radial direction of the central axis CX, the scrapers 12 protrude outward beyond the outer end of the cutter body 9. The scrapers 12 are detachable from the cutter body 9. The crushed rock material crushed by the disc cutter 10 is deposited on the ground below the cutter body 9. As the cutter body 9 rotates, the scrapers 12 pick up the crushed material deposited on the ground. A belt conveyor 18 is arranged behind the cutter body 9. The crushed material picked up by the scrapers 12 is supplied to the belt conveyor 18. The belt conveyor 18 transports the crushed material to the rear of the excavator 1.

[0018] The front gripper 8 is movably supported by the front body 6. A plurality of front grippers 8 are arranged around the front body 6. A plurality of front grippers 8 are arranged around the central axis CX. A hydraulic cylinder (not shown) connected to the front gripper 8 is arranged on the front body 6. The front gripper 8 moves in the radial direction of the central axis CX by the driving force generated by the hydraulic cylinder arranged on the front body 6.

[0019] The thrust jacks 4 are disposed between the forward section 2 and the aft section 3. The forward body 6 of the forward section 2 and the aft body 13 of the aft section 3 are connected via the thrust jacks 4. The thrust jacks 4 are hydraulic cylinders. Multiple thrust jacks 4 are provided. The thrust jacks 4 operate to change the relative positions of the forward section 2 and the aft section 3 in the fore-and-aft direction. When the thrust jacks 4 extend, the forward section 2 moves forward relative to the aft section 3. When the thrust jacks 4 operate so that the extension amounts of the multiple thrust jacks 4 differ from one another, the orientation of the forward section 2 relative to the aft section 3 changes.

[0020] The rear gripper 14 is movably supported by the rear body 13. A plurality of rear grippers 14 are arranged around the rear body 13. A plurality of rear grippers 14 are arranged around the central axis CX. A hydraulic cylinder (not shown) connected to the rear gripper 14 is arranged in the rear body 13. The rear gripper 14 moves in the radial direction of the central axis CX by the driving force generated by the hydraulic cylinder arranged in the rear body 13.

[0021] At least a portion of the main beam 15 is disposed aft of the rear fuselage section 3. The trailing bogie 16 is coupled to the rear of the main beam 15. The trailing bogie 16 is coupled to the rear of the main beam 15. The trailer section 5 and the trailing bogie 16 are towed by the forward fuselage section 2. The front portion of the main beam 15 is coupled to the forward body 6 of the forward fuselage section 2. A through hole is provided in the rear body 13. At least a portion of the main beam 15 is disposed in the through hole of the rear body 13. The front portion of the main beam 15 is coupled to the forward body 6 via the rear body 13. Workers can board a work space 15A of the main beam 15 to perform work. Equipment such as an engine, hydraulic equipment, a generator, concrete spraying equipment, a water tank, and a controller is mounted on the trailing bogie 16.

[0022] Rails 17 are laid in the tunnel. When the excavator 1 moves forward to excavate the excavation target, the trailing bogie 16 moves forward along the rails 17. When the excavator 1 moves backward, the excavator 1, including the forward section 2, the rear section, the thrust jack 4, and the trailer section 5, moves backward along the rails 17. The trailing bogie 16 has wheels that can run on the rails 17. The trailing bogie 16 moves along the rails 17. Note that the excavator 1 does not have to move along the rails. Tires may be attached to the excavator 1. The excavator 1 may move by rotation of the tires. The belt conveyor 18 is supported by the trailing bogie 16. The front part of the belt conveyor 18 is located in the forward section 2. The rear part of the belt conveyor 18 is located at the rear of the trailing bogie 16. The crushed material dropped by the scraper 12 to the front part of the belt conveyor 18 is transported to the rear part of the belt conveyor 18. The belt conveyor 18 supplies the pulverized material to a transport vehicle 50 arranged behind the excavator 1. After the pulverized material is loaded onto the bed of the transport vehicle 50, the transport vehicle 50 transports the pulverized material to a predetermined soil discharge position.

[0023] When excavating rock, the rear gripper 14 moves radially outward and is pressed against the inner wall of the tunnel being formed. By pressing the rear gripper 14 against the inner wall of the tunnel, the rear section 3 is fixed to the inner wall of the tunnel. After the rear gripper 14 moves radially outward to fix the rear section 3 to the inner wall of the tunnel, the front gripper 8 moves radially inward to move away from the inner wall of the tunnel. With the rear section 3 fixed to the inner wall of the tunnel, the thrust jack 4 extends while the cutter head 7 rotates, thereby excavating the rock. The cutter head 7 excavates the rock as it moves forward.

[0024] After the thrust jacks 4 are fully extended, the front grippers 8 move radially outward and are pressed against the inner wall of the tunnel being formed. By pressing the front grippers 8 against the inner wall of the tunnel, the forward fuselage section 2 is fixed to the inner wall of the tunnel. After the front grippers 8 move radially outward so as to fix the forward fuselage section 2 to the inner wall of the tunnel, the rear grippers 14 move radially inward so as to move away from the inner wall of the tunnel. With the forward fuselage section 2 fixed to the inner wall of the tunnel, the thrust jacks 4 retract, causing the forward fuselage section 2 and the trailer section 5 including the main beam 15 and the trailing bogie 16 to move forward.

[0025] After the rear section 3 and trailer section 5 move forward, the rear gripper 14 moves radially outward to secure the rear section 3 to the inner wall of the tunnel, and the front gripper 8 moves radially inward to move away from the inner wall of the tunnel. With the rear section 3 secured to the inner wall of the tunnel, the thrust jacks 4 extend while the cutter head 7 rotates, thereby excavating the rock. The cutter head 7 excavates the rock as it moves forward. By repeating the above-described operation, the rock is excavated little by little, and the formation of the tunnel progresses.

[0026] A worker riding on the main beam 15 performs reinforcement work on the tunnel immediately after it has been formed by the excavator 1. The reinforcement work includes drilling holes in the inner wall of the tunnel using a drill, laying wire mesh on the inner wall surface of the tunnel and then pouring concrete into the holes, inserting rock bolts into the holes after the concrete has been poured, sealing the holes with metal plates, and spraying liquid concrete onto the inner wall surface of the tunnel using a spray nozzle. The wire mesh laid on the inner wall surface of the tunnel is fixed to the inner wall surface by the heads of the rock bolts. The liquid concrete is sprayed onto the inner wall surface of the tunnel through the wire mesh. The liquid concrete hardens and turns into solid concrete, thereby reinforcing the tunnel.

[0027] Figure 3 is a schematic diagram of a reinforced tunnel according to an embodiment. In Figure 3, the dotted line Ta indicates the inner wall of the unreinforced tunnel immediately after it has been formed by the excavator 1. The inner diameter of the unreinforced tunnel is substantially equal to the outer diameter of the cutter head 7. The solid line Tb indicates the inner wall of the reinforced tunnel after reinforcement work has been carried out. The inner wall of the reinforced tunnel includes a reinforcing layer 31 formed of solid concrete. By forming the reinforcing layer 31, the inner diameter of the reinforced tunnel becomes smaller than the inner diameter of the unreinforced tunnel.

[0028] After the reinforced tunnel is formed, the excavator 1 retreats along the reinforced tunnel. The inner diameter of the reinforced tunnel is likely to be smaller than the outer diameter of the cutter head 7. At least a portion of the cutter head 7 may get caught on the inner wall of the reinforced tunnel, making it difficult for the excavator 1 to retreat along the reinforced tunnel.

[0029] Therefore, before the excavator 1 is retracted along the reinforced tunnel, the front end of the excavator 1 is adjusted. The adjustment of the front end of the excavator 1 includes a process of reducing the outer diameter of the cutter head 7. The process of reducing the outer diameter of the cutter head 7 includes a process of removing parts from the cutter head 7. In the embodiment, the process of removing parts from the cutter body 9 includes a process of removing parts such as the disc cutter 10, the outer plate 11, and the scraper 12 that are arranged on the periphery of the cutter body 9. Furthermore, the process of reducing the outer diameter of the cutter head 7 includes a process of moving the parts of the cutter head 7 radially inward. The process of moving the parts of the cutter head 7 radially inward includes a process of storing or laying down the parts that are arranged on the periphery of the cutter body 9 radially inward. In the following description, parts that are moved to reduce the outer diameter of the cutter head 7, such as the disk cutter 10, outer plate 11, and scraper 12 arranged on the periphery of the cutter body 9, will be referred to as peripheral parts as appropriate.

[0030] In the radial direction of the central axis CX, the peripheral parts protrude outward beyond the outer end of the cutter body 9. The peripheral parts are detachable from the cutter body 9. The peripheral parts are movable relative to the cutter body 9. When the peripheral parts are removed or moved from the cutter body 9, the outer diameter of the cutter head 7 is reduced. The reduced outer diameter of the cutter head 7 allows the cutter head 7 to pass through the reinforced tunnel. The reduced outer diameter of the cutter head 7 allows the excavator 1 to retreat along the reinforced tunnel.

[0031] [Lattice Tunnel] Fig. 4 is a diagram schematically showing a lattice tunnel 100 according to an embodiment. In the embodiment, ore is mined based on the block caving method. As shown in Fig. 4, when ore is mined based on the block caving method, a lattice tunnel 100 is formed underground using an excavator 1. After the lattice tunnel 100 is formed, the ceiling wall of the draw point of the lattice tunnel 100 is undercut and blasted. By undercutting the ceiling wall of the draw point and blasting, the ore naturally collapses, and the ore is mined.

[0032] The lattice tunnel 100 includes a rectangular outer tunnel 200, a drift tunnel 300 provided inside the outer tunnel 200, and a cross-cut tunnel 400 provided inside the outer tunnel 200 so as to intersect with the drift tunnel 300.

[0033] The outer perimeter tunnel 200 includes a first portion 201 extending in a first direction, a second portion 202 extending in a second direction intersecting the first direction, a third portion 203 extending in the first direction, and a fourth portion 204 extending in the second direction. As an example, the first direction is the north-south direction. The second direction is the east-west direction. The first portion 201 and the third portion 203 each extend in the north-south direction. The first portion 201 is located east of the third portion 203. The second portion 202 and the fourth portion 204 each extend in the east-west direction. The second portion 202 is located north of the fourth portion 204.

[0034] The northern end of the first portion 201 is connected to the eastern end of the second portion 202. The western end of the second portion 202 is connected to the northern end of the third portion 203. The southern end of the third portion 203 is connected to the western end of the fourth portion 204. The eastern end of the fourth portion 204 is connected to the southern end of the first portion 201.

[0035] The drift tunnel 300 extends in the north-south direction. A plurality of drift tunnels 300 are provided. The plurality of drift tunnels 300 are provided substantially parallel to one another. In the embodiment, four drift tunnels 300 are provided. The drift tunnels 300 include a first drift 301, a second drift 302, a third drift 303, and a fourth drift 304. In the east-west direction, the plurality of drift tunnels 300 are arranged between the first portion 201 and the third portion 203. From east to west, the first drift 301, the second drift 302, the third drift 303, and the fourth drift 304 are arranged in this order.

[0036] The southern ends of the first drift 301, the second drift 302, the third drift 303, and the fourth drift 304 are connected to the fourth portion 204. The northern ends of the first drift 301, the second drift 302, the third drift 303, and the fourth drift 304 are connected to the second portion 202.

[0037] The crosscut tunnel 400 extends substantially in the east-west direction. In this embodiment, the crosscut tunnel 400 inclines northward toward the east. A plurality of crosscut tunnels 400 are provided. The plurality of crosscut tunnels 400 are provided substantially parallel to one another. In this embodiment, twelve crosscut tunnels 400 are provided. The crosscut tunnels 400 include a first crosscut 401, a second crosscut 402, a third crosscut 403, a fourth crosscut 404, a fifth crosscut 405, a sixth crosscut 406, a seventh crosscut 407, an eighth crosscut 408, a ninth crosscut 409, a tenth crosscut 410, an eleventh crosscut 411, and a twelfth crosscut 412. In the north-south direction, the plurality of crosscut tunnels 400 are arranged between the second section 202 and the fourth section 204. From south to north, the cross cuts are arranged in the following order: first cross cut 401, second cross cut 402, third cross cut 403, fourth cross cut 404, fifth cross cut 405, sixth cross cut 406, seventh cross cut 407, eighth cross cut 408, ninth cross cut 409, tenth cross cut 410, eleventh cross cut 411, and twelfth cross cut 412.

[0038] The western end of the first crosscut 401 is connected to the first drift 301. The western end of the second crosscut 402 is connected to the second drift 302. The western end of the third crosscut 403 is connected to the third drift 303. The western end of the fourth crosscut 404 is connected to the fourth drift 304. The eastern ends of the first crosscut 401, the second crosscut 402, the third crosscut 403, and the fourth crosscut 404 are each connected to the first portion 201.

[0039] The western ends of the fifth crosscut 405, the sixth crosscut 406, the seventh crosscut 407, and the eighth crosscut 408 are connected to the third portion 203. The eastern ends of the fifth crosscut 405, the sixth crosscut 406, the seventh crosscut 407, and the eighth crosscut 408 are connected to the first portion 201.

[0040] The western ends of the ninth crosscut 409, the tenth crosscut 410, the eleventh crosscut 411, and the twelfth crosscut 412 are connected to the third portion 203. The eastern end of the ninth crosscut 409 is connected to the first drift 301. The eastern end of the tenth crosscut 410 is connected to the second drift 302. The eastern end of the eleventh crosscut 411 is connected to the third drift 303. The eastern end of the twelfth crosscut 412 is connected to the fourth drift 304.

[0041] A mining area 500 where minerals are mined is defined inside the outer periphery tunnel 200. The mining area 500 and the outer periphery tunnel 200 do not overlap. The mining area 500 and at least a portion of the drift tunnel 300 overlap. The mining area 500 and at least a portion of the cross-cut tunnel 400 overlap.

[0042] [Work procedure generation device] Figure 5 is a block diagram showing a work procedure generation device 20 according to an embodiment. The work procedure generation device 20 generates a work procedure for forming the lattice tunnel 100. If the work procedure for forming the lattice tunnel 100 is inappropriate, the workability of tunnel excavation may decrease. The work procedure generation device 20 generates a work procedure for forming the lattice tunnel 100 so as to suppress a decrease in the workability of tunnel excavation.

[0043] The work procedure generation device 20 includes a computer system 1000. The work procedure generation device 20 has a processor 1001 such as a CPU (Central Processing Unit), a main memory 1002 including a non-volatile memory such as ROM (Read Only Memory) and a volatile memory such as RAM (Random Access Memory), a storage 1003, and an interface 1004 including an input / output circuit. The functions of the work procedure generation device 20 are stored in the storage 1003 as a computer program. The processor 1001 reads the computer program from the storage 1003 and loads it into the main memory 1002, and generates a work procedure for forming the lattice tunnel 100 in accordance with the computer program. The computer program may be distributed to the computer system 1000 via a network.

[0044] [Tunnel Excavation Method] Next, a tunnel excavation method according to the embodiment will be described. Figures 6 and 7 are diagrams for explaining the procedure of work when forming the lattice-pattern tunnel 100 according to the embodiment.

[0045] In an embodiment, the work procedure generation device 20 generates a work procedure for forming the lattice tunnel 100 so that, after a portion of the outer periphery tunnel 200 has been formed, at least one of the drift tunnel 300 and the crosscut tunnel 400 is connected to the portion of the formed outer periphery tunnel 200. The work procedure generation device 20 generates a work procedure so that an end of a new tunnel, which is a tunnel to be newly formed, is connected to a middle portion of an existing tunnel, which is a tunnel that has already been formed. In other words, the work procedure generation device 20 generates a work procedure so that the new tunnel is connected to the existing tunnel from its side. The excavator 1 excavates the rock mass based on the work procedure generated by the work procedure generation device 20.

[0046] As shown in Fig. 6 , the excavator 1 excavates the rock mass, which is the excavation target, in a first direction and a second direction intersecting the first direction to form a portion of the outer tunnel 200. As indicated by arrow S1 in Fig. 6 , the excavator 1 excavates the rock mass so as to form a first portion 201 and a second portion 202 of the outer tunnel 200. The excavator 1 advances north while excavating the rock mass to form the first portion 201, and then changes course westward at the northern end of the first portion 201 and advances westward while excavating the rock mass to form the second portion 202.

[0047] After the first portion 201 and the second portion 202 of the outer circumferential tunnel 200 are formed, the excavator 1 retreats along the second portion 202 and the first portion 201 and returns to the southern end of the first portion 201. After returning to the southern end of the first portion 201, the excavator 1 starts excavating to form the drift tunnel 300 and the crosscut tunnel 400.

[0048] As shown in Fig. 7 , the boring machine 1 excavates the rock mass so as to reach an existing tunnel consisting of a portion of an already formed outer periphery tunnel 200, thereby forming at least one of a drift tunnel 300 and a cross-cut tunnel 400. In the example shown in Fig. 7 , the existing tunnel is the first portion 201 and the second portion 202 of the outer periphery tunnel 200. The boring machine 1 excavates the rock mass so as to reach the first portion 201 and the second portion 202, which are the existing tunnel.

[0049] In this embodiment, as shown by arrow S2 in Figure 7, the excavator 1 excavates the rock mass so as to form a first drift 301 connected to the second portion 202 and a second crosscut 402 connected to the first portion 201. The excavator 1 advances westward from the southern end of the first portion 201 while excavating the rock mass to form part of the fourth portion 204, then changes course north and advances north while excavating the rock mass to form the first drift 301. The northern end of the first drift 301 connects to the second portion 202.

[0050] After the first drift 301 is formed, the excavator 1 retreats along the first drift 301 and returns to the vicinity of the southern end of the first drift 301. After returning to the vicinity of the southern end of the first drift 301, the excavator 1 changes course to the east (northeast) and advances east (northeast) while excavating the bedrock to form the second crosscut 402. The eastern end of the second crosscut 402 connects to the first portion 201.

[0051] FIG. 8 is a perspective view schematically illustrating a state in which the second crosscut 402 is connected to the first section 201 according to the embodiment. As indicated by arrow S2 in FIG. 7 , the excavator 1 excavates the rock mass to reach the first section 201, which is the existing tunnel, and forms the second crosscut 402. The second crosscut 402 is a new tunnel formed after the first section 201. The second crosscut 402 is connected to the first section 201 from the side of the first section 201. After the eastern end of the second crosscut 402, which is the new tunnel, is connected to the first section 201, which is the existing tunnel, the excavator 1 is stopped. As shown in FIG. 8 , an operator can approach the front end of the excavator 1 from the first section 201, which is the existing tunnel. The transport vehicle 70 can enter the second crosscut 402 from the first section 201. A predetermined operation is performed so that the excavator 1 can retreat. The transport vehicle 70 carries, for example, an operator or work tools required for the operation required for the excavator 1 to retreat. An electric cable 61 is arranged in the first portion 201, and a lighting device 60 is connected to the electric cable 61. The front end of the excavator 1 is illuminated by the lighting device 60 arranged in the first portion 201.

[0052] An operator can approach the front end of the excavator 1 from the first portion 201 and adjust the front end of the excavator 1. Adjustment of the front end of the excavator 1 includes maintenance of the front end of the excavator 1. Adjustment of the front end of the excavator 1 includes a process of attaching parts to the front end of the excavator 1. Adjustment of the front end of the excavator 1 includes a process of removing parts from the front end of the excavator 1. Adjustment of the front end of the excavator 1 includes a process of reducing the outer diameter of the cutter head 7 disposed at the front end of the excavator 1. The process of reducing the outer diameter of the cutter head 7 includes one or both of a process of removing parts from the cutter head 7 and a process of moving parts of the cutter head 7 radially inward. The lighting device 60 illuminates the front end of the excavator 1 and the first portion 201 and second cross cut 402 around the front end of the excavator 1, improving the workability of the work of adjusting the front end of the excavator 1. In addition, the work space is larger than when working in a dead end, improving the workability.

[0053] In adjusting the front end of the excavator 1, the worker may adjust the front end of the excavator 1 by approaching the front end of the excavator 1 from the first part 201, and may also adjust the front end of the excavator 1 by approaching the front end of the excavator 1 from behind the front end of the excavator 1. In other words, the worker may adjust the front end of the excavator 1 from both in front of and behind the front end of the excavator 1.

[0054] 9 is a diagram schematically illustrating a state in which the second crosscut 402 is connected to the first portion 201 according to the embodiment. Reinforcement work is carried out on the second crosscut 402, which is a new tunnel immediately after it has been formed by the excavator 1. As shown in FIG. 9 , a reinforcing layer 31 is formed on the inner wall of the second crosscut 402.

[0055] After the second cross cut 402 is formed to connect to the first portion 201, the excavator 1 retreats along the second cross cut 402. The reinforcing layer 31 reduces the inner diameter of the second cross cut 402. Before the excavator 1 retreats along the second cross cut 402, a process for reducing the outer diameter of the cutter head 7 is performed. As described above, the process for reducing the outer diameter of the cutter head 7 includes one or both of the process of removing parts from the cutter head 7 and the process of moving the parts of the cutter head 7 radially inward. The process of removing parts from the cutter head 7 includes the process of removing peripheral parts from the cutter body 9. The process of moving the parts of the cutter head 7 radially inward includes the process of storing or laying the peripheral parts radially inward. After the front end of the second cross cut 402, which is the new tunnel, is connected to the first portion 201, which is the existing tunnel, the excavator 1 is stopped. With the excavator 1 stopped, the process of reducing the outer diameter of the cutter head 7 is carried out from the first section 201 side. That is, with the excavator 1 stopped, the process of reducing the outer diameter of the cutter head 7 is carried out from the front side of the cutter head 7. Because the front end of the second cross cut 402 is connected to the first section 201, which is the existing tunnel, the worker can approach the cutter head 7 from the first section 201 and smoothly carry out the process of reducing the outer diameter of the cutter head 7.

[0056] The outer diameter of the cutter head 7 is reduced by removing the peripheral parts from the cutter body 9 or by moving them radially inward. The reduced outer diameter of the cutter head 7 allows the cutter head 7 to pass through the second crosscut 402 on which the reinforcing layer 31 is formed. The reduced outer diameter of the cutter head 7 allows the excavator 1 to retreat along the second crosscut 402, which is a new tunnel.

[0057] Also, after the excavator 1 retreats, the operator can approach the second crosscut 402 from the first part 201 and form a reinforcing layer 32 on the inner wall of the second crosscut 402 in a predetermined range including the front end of the second crosscut 402.

[0058] In this embodiment, the northern end of the first drift 301, which is a new tunnel, is connected to the second section 202, which is an existing tunnel. Therefore, when the excavator 1 that formed the first drift 301 retreats through the first drift 301, an operator can approach the front end of the excavator 1 from the second section 202 to adjust the front end of the excavator 1 or form a reinforcing layer 32 at the northern end of the inner wall of the first drift 301.

[0059] The excavator 1 excavates the rock mass to reach the first and second portions 201 and 202 of the existing tunnel, and sequentially forms the drift tunnel 300 and the crosscut tunnel 400. As described with reference to Figure 7, the excavator 1 advances while excavating the rock mass along the arrow S2, thereby forming the first drift 301 and the second crosscut 402. After the first drift 301 and the second crosscut 402 are formed, the excavator 1 retreats to the southern end of the first drift 301.

[0060] FIG. 10 is a diagram illustrating the procedure for forming a lattice tunnel according to the embodiment. After retreating to the southern end of the first drift 301, the excavator 1 advances along arrow S3 in FIG. 10 while excavating the rock mass. By advancing along arrow S3 while excavating the rock mass, the second drift 302 and the third crosscut 403 are formed. After forming the second drift 302, for example, the excavator 1 retreats to near the southern end of the second drift 302 and advances eastward (northeastward) while excavating the rock mass to form the third crosscut 403. The northern end of the second drift 302 connects to the second section 202. The eastern end of the third crosscut 403 connects to the first section 201. After the second drift 302 and the third crosscut 403 are formed, the excavator 1 retreats to the southern end of the second drift 302.

[0061] Because the northern end of the second drift 302 connects to the second section 202, when the excavator 1 retreats along the second drift 302, an operator can approach the front end of the excavator 1 from the second section 202. Because the eastern end of the third crosscut 403 connects to the first section 201, when the excavator 1 retreats along the third crosscut 403, an operator can approach the front end of the excavator 1 from the first section 201.

[0062] After retreating to the southern end of the second drift 302, the excavator 1 advances along arrow S4 in FIG. 10 while excavating the rock. As the excavator 1 advances along arrow S4 while excavating the rock, the third drift 303 and the fourth crosscut 404 are formed. For example, after forming the third drift 303, the excavator 1 retreats to the vicinity of the southern end of the third drift 303 and advances eastward (northeastward) while excavating the rock to form the fourth crosscut 404. The northern end of the third drift 303 connects to the second section 202, which is the existing tunnel. The eastern end of the fourth crosscut 404 connects to the first section 201, which is the existing tunnel. After the third drift 303 and the fourth crosscut 404 are formed, the excavator 1 retreats to the southern end of the third drift 303.

[0063] After retreating to the southern end of the third drift 303, the excavator 1 advances along arrow S5 in FIG. 10 while excavating the rock. As the excavator 1 advances along arrow S5 while excavating the rock, the fourth drift 304, the fifth crosscut 405, the seventh crosscut 407, the ninth crosscut 409, and the eleventh crosscut 411 are formed. After forming, for example, the fourth drift 304, the excavator 1 retreats to the vicinity of the southern end of the fourth drift 304 and advances eastward (northeastward) while excavating the rock to form, for example, the fifth crosscut 405. After forming the fifth crosscut 405, the excavator 1 repeatedly advances and retreats to sequentially form the seventh crosscut 407, the ninth crosscut 409, and the eleventh crosscut 411. The northern end of the fourth drift 304 connects to the second section 202, which is the existing tunnel. The eastern ends of the fifth crosscut 405 and the seventh crosscut 407 connect to the first portion 201, which is the existing tunnel. The eastern end of the ninth crosscut 409 connects to the first drift 301, which is the existing tunnel, and the eastern end of the eleventh crosscut 411 connects to the third drift 303, which is the existing tunnel. After the fourth drift 304, the fifth crosscut 405, the seventh crosscut 407, the ninth crosscut 409, and the eleventh crosscut 411 have been formed, the excavator 1 retreats to the southern end of the fourth drift 304.

[0064] After retreating to the southern end of the fourth drift 304, the excavator 1 advances along arrow S6 in FIG. 10 while excavating the rock. As the excavator 1 advances along arrow S6 while excavating the rock, the third section 203, the sixth crosscut 406, the eighth crosscut 408, the tenth crosscut 410, and the twelfth crosscut 412 are formed. After forming, for example, the third section 203, the excavator 1 retreats to the vicinity of the southern end of the third section 203 and advances eastward (northeastward) while excavating the rock, so as to form, for example, the sixth crosscut 406. After forming the sixth crosscut 406, the excavator 1 repeatedly advances and retreats so as to sequentially form the eighth crosscut 408, the tenth crosscut 410, and the twelfth crosscut 412. The northern end of the third section 203 connects to the second section 202. The eastern ends of the sixth crosscut 406 and the eighth crosscut 408 connect to the first section 201, which is the existing tunnel. The eastern end of the tenth crosscut 410 connects to the second drift 302, which is the existing tunnel. The eastern end of the twelfth crosscut 412 connects to the fourth drift 304, which is the existing tunnel. After the third section 203, the sixth crosscut 406, the eighth crosscut 408, the tenth crosscut 410, and the twelfth crosscut 412 have been formed, the excavator 1 retreats to the southern end of the third section 203.

[0065] After retreating to the southern end of the third section 203, the excavator 1 sequentially excavates the unexcavated section Sm indicated by the dotted line. By excavating the unexcavated section Sm, the lattice tunnel 100 is formed. After the lattice tunnel 100 is formed, the excavator 1 advances along the arrow S7 in Figure 8 and retreats from the lattice tunnel 100.

[0066] [Effects] As described above, according to the embodiment, after the first portion 201 and the second portion 202 of the outer tunnel 200 are formed as the existing tunnel, the excavator 1 excavates the bedrock so as to connect to the existing tunnel in order to form at least a portion of the drift tunnel 300 and the cross-cut tunnel 400. Because the excavation work procedure by the excavator 1 is determined so that the new tunnel connects to the existing tunnel, a decrease in workability is suppressed when forming the lattice tunnel 100. As described above, after the new tunnel is formed, a process for adjusting the front end of the excavator 1 is performed before retracting the excavator 1. In the embodiment, the operator can approach the cutter head 7 from the first portion 201 and smoothly perform the process for adjusting the front end of the excavator 1, thereby improving workability when adjusting the front end of the excavator 1. Because the excavation work procedure by the excavator 1 is determined so that the front end of the new tunnel connects to the existing tunnel at many locations, workability is suppressed when forming the lattice tunnel 100. Furthermore, according to the embodiment, the work space is larger than when working in a dead end, improving workability.

[0067] FIG. 11 is a schematic diagram illustrating a state in which a new tunnel (tunnel before reinforcement) is not connected to an existing tunnel. As described above, after the new tunnel is formed, a process of removing peripheral parts from the cutter body 9 is performed in order to retract the excavator 1. As shown in FIG. 11 , when the new tunnel (tunnel before reinforcement) is not connected to the existing tunnel, i.e., when the front end of the new tunnel is a dead end (cul-de-sac), removing the peripheral parts from the cutter body 9 becomes difficult. That is, when the front end of the new tunnel is a dead end, the presence of rock in front of and around the cutter head 7 makes it difficult for the operator to approach or adjust the front end of the excavator 1. When the front end of the new tunnel is a dead end, the operator must remove the peripheral parts from the rear of the cutter head 7, or move from the rear of the cutter head 7 to the front of the cutter head 7 and then remove the peripheral parts. When removing the peripheral parts from the rear of the cutter head 7, the operator's workability is reduced due to insufficient work space. As shown in FIG. 11 , when removing peripheral parts after moving from the rear of the cutter head 7 to the front of the cutter head 7, the workability is reduced due to the dead end and insufficient lighting. Furthermore, the work required to prevent the front end of the new tunnel from collapsing reduces workability. Furthermore, the reinforcement work is performed by a worker riding on the main beam 15. Therefore, it is difficult for the worker to reinforce the inner wall of the new tunnel (tunnel before reinforcement) ahead of the main beam 15. When forming the lattice tunnel 100, if the front end of the new tunnel has many dead ends (dead ends), workability is reduced when forming the lattice tunnel 100.

[0068] In this embodiment, the excavation work procedure by the excavator 1 is determined so that the new tunnel will be connected to the existing tunnel. That is, when forming the lattice tunnel 100, the excavation work procedure by the excavator 1 is determined so that the front end of the new tunnel will be connected to the existing tunnel in many places and the new tunnel will have fewer dead ends (cul-de-sacs). By increasing the number of places where the front end of the new tunnel is connected to the existing tunnel, a decrease in tunnel excavation workability is suppressed when forming the lattice tunnel 100. According to this embodiment, as described with reference to FIGS. 8 and 9 , the worker can approach the front end of the excavator 1 from the existing tunnel or adjust the front end of the excavator 1. The front end of the excavator 1 is adjusted from the existing tunnel.

[0069] [Another Embodiment] Figure 12 is a diagram illustrating the procedure for forming a lattice tunnel according to another embodiment. As shown in Figure 12, the excavator 1 may advance while excavating as indicated by arrow S1 to form a portion of the lattice tunnel 100, then advance while excavating as indicated by arrow S2 to form a portion of the lattice tunnel 100, and then advance while excavating as indicated by arrows S3, S4, S5, and S6 to sequentially form portions of the lattice tunnel 100. Even in the example shown in Figure 12, there are few dead ends (cul-de-sacs) at the front end of the new tunnel, which prevents a decrease in workability when forming the lattice tunnel 100. An operator can approach the front end of the excavator 1 in the new tunnel from the existing tunnel and adjust the front end of the excavator 1.

[0070] In the above-described embodiment, an operator approaches the front end of the excavator 1 that is located from the existing tunnel to the new tunnel and adjusts the front end of the excavator 1. In the above-described embodiment, an adjustment robot may approach the front end of the excavator 1 that is located from the existing tunnel to the new tunnel and adjust the front end of the excavator 1.

[0071] In the above embodiment, the outer tunnel 200 is rectangular. However, the outer tunnel 200 does not have to be rectangular. The outer tunnel 200 may have five or more corners. The outer tunnel 200 may be elliptical, for example.

[0072] DESCRIPTION OF SYMBOLS 1...Excavator, 2...Forward body section, 3...Rear body section, 4...Thrust jack, 5...Trailer section, 6...Front body, 7...Cutter head, 8...Front gripper, 9...Cutter body, 10...Disc cutter, 11...Outer plate, 12...Scraper, 13...Rear body, 14...Rear gripper, 15...Main beam, 15A...Work space, 16...Following carriage, 17...Rail, 18...Conveyor belt A, 20...work procedure generation device, 31...reinforcement layer, 32...reinforcement layer, 50...transport vehicle, 60...lighting device, 61...electric cable, 70...transport vehicle, 100...lattice tunnel, 200...periphery tunnel, 201...first part, 202...second part, 203...third part, 204...fourth part, 300...drift tunnel, 301...first drift, 302...second drift, 303...third drift ft, 304...fourth drift, 400...crosscut tunnel, 401...first crosscut, 402...second crosscut, 403...third crosscut, 404...fourth crosscut, 405...fifth crosscut, 406...sixth crosscut, 407...seventh crosscut, 408...eighth crosscut, 409...ninth crosscut, 410...tenth crosscut, 411...eleventh crosscut, 412...twelfth crosscut, 500...mining area, 1000...computer system, 1001...processor, 1002...main memory, 1003...storage, 1004...interface, S1...arrow, S2...arrow, S3...arrow, S4...arrow, S5...arrow, S6...arrow, S7...arrow, Sm...unattracted portion, Ta...line, Tb...line.

Claims

1. A tunnel excavation method for using an excavator to form a lattice-patterned tunnel including a perimeter tunnel, a drift tunnel provided inside the perimeter tunnel, and a cross-cut tunnel provided inside the perimeter tunnel so as to intersect with the drift tunnel, the tunnel excavation method comprising: excavating an excavation target with the excavator in a first direction and a second direction intersecting the first direction to form a part of the perimeter tunnel; and excavating the excavation target so as to reach an existing tunnel consisting of a part of the formed perimeter tunnel, to form at least one of the drift tunnel and the cross-cut tunnel.

2. The tunnel excavation method according to claim 1, comprising: stopping the excavator after an end of a new tunnel consisting of at least one of the formed drift tunnel and the crosscut tunnel is connected to the existing tunnel; and reversing the excavator along the new tunnel after a front end of the excavator has been adjusted from the existing tunnel.

3. A tunnel excavation method as claimed in claim 2, wherein the excavator has a cutter head disposed at a front end of the excavator, and the adjustment of the front end of the excavator includes a process of reducing an outer diameter of the cutter head.

4. The tunnel excavation method according to claim 3, wherein adjusting the front end of the excavator includes removing parts from the cutter head.

5. A tunnel excavation method for forming a lattice-patterned tunnel using an excavator, comprising: excavating an excavation target using the excavator so as to form a first tunnel; after the first tunnel is formed, excavating the excavation target so as to form a second tunnel connected to the first tunnel; after an end of the second tunnel is connected to the first tunnel, stopping the excavator; after the excavator has stopped, approaching a front end of the excavator from the first tunnel to adjust the front end of the excavator; and after the front end of the excavator has been adjusted, retracting the excavator along the second tunnel.

6. A tunnel excavation method as claimed in claim 5, wherein the excavator has a cutter head disposed at a front end of the excavator, and adjusting the front end of the excavator includes reducing an outer diameter of the cutter head.

7. The tunnel excavation method according to claim 6, wherein adjusting the front end of the excavator includes removing parts from the cutter head.

8. The tunnel excavation method according to claim 5, further comprising forming a reinforcing layer on a predetermined area of ​​the inner wall of the second tunnel including the front end of the second tunnel after retracting the excavator along the second tunnel.

9. The tunnel excavation method according to claim 5, wherein in adjusting the front end of the excavator, the front end of the excavator is illuminated by a lighting device arranged in the first tunnel.

10. A tunnel excavation method as described in claim 5, wherein in adjusting the front end of the excavator, the front end of the excavator is adjusted by approaching the front end of the excavator from the first tunnel, and the front end of the excavator is adjusted by approaching the front end of the excavator from behind the front end of the excavator.

11. The tunnel excavation method according to claim 5, wherein the second tunnel is connected to the first tunnel from a side of the first tunnel.

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