Ground exploration equipment

Abstract

Accurately explore the condition of the ground. [Solution] The natural ground exploration device is a natural ground exploration device 40 installed in a tunnel boring machine 100 for exploring the strength of the natural ground, and comprises an exploration device main body provided inside the tunnel boring machine, a rod that can be retracted into and out of the exploration device main body and can be protruded from the outer periphery of the tunnel boring machine, an adjustment device that adjusts the pushing force of the rod from the exploration device main body, and a control device that protrudes the rod with a first pushing force adjusted by the adjustment device, and then protrudes the rod with a second pushing force adjusted by the adjustment device and greater than the first pushing force.

Description

[Technical field]

[0001] The present invention relates to a natural ground exploration device. [Background technology]

[0002] In the shield tunneling method, a tunnel is excavated while acquiring information on the natural ground in the direction ahead of the shield machine or directly above the shield machine. Conventionally, there is known an exploration system that acquires information on the natural ground at multiple locations near the tunnel face and determines the stability of the natural ground based on the information on the multiple locations (see, for example, Patent Document 1, etc.).

[0003] According to the technology described in Patent Document 1, the stability of the ground is judged based on the measurement results of an upper exploration device installed on the top of the shield machine, a front exploration device installed inside the shield machine, and a cutting resistance detection device installed on the cutter head. The upper exploration device can appear and disappear from the outer shell of the shield machine and penetrate into the ground located above the shield machine, measuring the penetration pressure and penetration amount into the ground. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-196068 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the upper exploration device of Patent Document 1 above cannot detect the presence or absence of cavities between the shield machine and the ground, and if the ground is soft, no pressure is generated when the rod of the upper exploration device penetrates the ground, and the rod may not stop, which may make it impossible to accurately measure the penetration pressure or penetration amount.

[0006] Therefore, an object of the present invention is to provide a natural ground exploration device capable of accurately exploring the state of the natural ground. [Means for solving the problem]

[0007] The first natural ground exploration device of the present invention is a natural ground exploration device that is installed on a tunnel boring machine for exploring the strength of natural ground, and comprises an exploration device main body provided inside the tunnel boring machine, a rod that is retractable from the exploration device main body and can protrude to the outside from the outer periphery of the tunnel boring machine, an adjustment device that adjusts the pushing force of the rod from the exploration device main body, and a control device that protrudes the rod with a first pushing force adjusted by the adjustment device, and then protrudes the rod with a second pushing force adjusted by the adjustment device and greater than the first pushing force.

[0008] The second natural ground exploration device of the present invention is a natural ground exploration device installed on a tunnel boring machine for exploring the strength of the natural ground, and comprises a measuring device provided on the tunnel boring machine for measuring at least one of the void volume of the natural ground and the stability of the natural ground, a moving device for moving the measuring device relative to the tunnel boring machine, and a control device for controlling the moving device to move the measuring device in the opposite direction to the tunnel boring machine at the same speed as the tunnel boring machine. Effect of the Invention

[0009] According to the natural ground exploration device of the present invention, the state of the natural ground can be accurately explored. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a tunnel boring machine according to the first embodiment. [Diagram 2] FIG. 2 is a diagram showing the cutter head as viewed from the +X direction. [Diagram 3] 3(a) and 3(b) are enlarged, partially cut-away views of the natural ground exploration device and its vicinity. [Figure 4] FIG. 4 is a block diagram showing a control system of the tunnel boring machine according to the first embodiment. [Diagram 5]FIG. 5(a) is a diagram showing a boring data table, FIG. 5(b) is a diagram showing a pushing force table, and FIG. 5(c) is a diagram for explaining each point in FIG. 5(a). [Figure 6] FIG. 6 is a flowchart (part 1) showing the operation of the tunnel boring machine. [Figure 7] FIG. 7 is a flowchart (part 2) showing the operation of the tunnel boring machine. [Figure 8] Figures 8(a) and 8(b) are diagrams (part 1) for explaining the excavation of one segment using a tunnel boring machine. [Figure 9] FIG. 9 is a diagram (part 2) for explaining the excavation of one segment using a tunnel boring machine. [Figure 10] FIG. 10(a) is a diagram showing a normal gap, and FIG. 10(b) is a diagram showing an example of a cavity that is larger than the normal gap. [Figure 11] FIG. 11 is a block diagram showing a control system according to a modified example of the first embodiment. [Figure 12] FIG. 12(a) is a diagram showing a first natural ground exploration device according to the second embodiment, and FIG. 12(b) is a diagram showing a second natural ground exploration device according to the second embodiment. [Figure 13] FIG. 13 is a diagram showing a natural rock exploration device and an X-drive mechanism according to the third embodiment. [Figure 14] 14(a) and 14(b) are diagrams for explaining the processing using the natural ground exploration device of FIG. [Figure 15] FIG. 15 is a diagram showing a modification of the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] First Embodiment Hereinafter, a first embodiment of a tunnel boring machine equipped with a natural ground exploration device will be described in detail with reference to Figs.

[0012] Fig. 1 is a cross-sectional view showing the schematic configuration of a tunnel boring machine 100 according to a first embodiment. In Fig. 1, hatching showing a cross section is omitted to avoid complicating the drawing. In this first embodiment, a case will be described in which the tunnel boring machine 100 is a shield machine used in a shield tunneling method.

[0013] The tunnel boring machine 100 excavates the ground (natural ground) to form an excavation hole 204, and constructs a shield tunnel TL (tunnel) by assembling segment rings 202 to cover the inner wall of the excavation hole 204. Note that the tunnel boring machine 100 may be a machine other than a shield machine, for example, a boring machine installed at the tip of a jacking pipe in a jacking method.

[0014] In this first embodiment, the direction in which the tunnel boring machine 100 advances (towards the tunnel face, forward) is the +X direction, and the tunnel entrance side (rear) is the -X direction. The left-right direction of the tunnel boring machine 100 is the Y-axis direction, with the left side in the direction of advancement being the +Y direction, and the right side in the direction of advancement being the -Y direction. Furthermore, the up-down direction of the tunnel boring machine 100 is the Z-axis direction, with the upward direction being the +Z direction, and the downward direction being the -Z direction.

[0015] The tunnel boring machine 100 is a mud pressure type shield machine used in a mud pressure shield construction method, and as shown in Fig. 1, has a cylindrical body 10. The body 10 has a cylindrical outer shell 11 extending along the axial direction of the shield tunnel TL (the X-axis direction in Fig. 1), a cutter head 20 that is rotationally driven in front of the outer shell 11, and a partition wall 12 provided within the outer shell 11 and arranged opposite the -X side of the cutter head 20. The cross-sectional shape of the outer shell 11 is not limited to a circle, and may be an ellipse or a rectangle.

[0016] The cutter head 20 is a disk-shaped structure having an outer diameter approximately equal to that of the outer shell 11. FIG. 2 shows the cutter head 20 as viewed from the +X direction. The cutter head 20 has spoke portions 21 extending radially from the rotation axis AX1, an annular ring portion 22, and a plurality of cutter bits 24 arranged at predetermined intervals in the radial direction on the +X side surface of the spoke portions 21. The arrangement of the plurality of cutter bits 24 is an example. The spoke portions 21 may be provided with a plurality of types of cutter bits.

[0017] In the cutter head 20, an opening 25 is formed between adjacent spoke portions 21. Soil excavated by the multiple cutter bits 24 is guided through the openings 25 between the spoke portions 21 into a chamber CB (see FIG. 1) defined by the cutter head 20, the partition wall 12, and the outer shell 11. Although not shown, the spoke portions 21 and the partition wall 12 are provided with members (such as a stirring rod) for stirring the excavated soil remaining in the chamber CB.

[0018] As shown in FIG. 1, an annular cutter drum 13 that rotates together with the cutter head 20 is rotatably supported on the partition wall 12.

[0019] The cutter drum 13 is rotated around a rotation axis AX1 by a plurality of motors 14. The motors 14 may be electric motors or hydraulic motors. A control device 90 in FIG. 4 controls the operation of the motors 14 to control the direction and speed of rotation of the cutter head 20.

[0020] A screw conveyor 30 is provided in the outer shell 11 of the tunnel boring machine 100 to convey the excavated soil retained in the chamber CB to the rear of the tunnel boring machine 100. The screw conveyor 30 has a cylindrical case and a screw provided inside the case, and the excavated soil in the chamber CB is conveyed to the rear of the partition wall 12 by rotation of the screw. The excavated soil conveyed to the rear by the screw conveyor 30 is transported through the shield tunnel TL by a soil transporting cart (not shown) and discharged to the ground. The excavated soil may be conveyed to the ground by a soil discharge system combining a conveyor such as a belt conveyor or a screw conveyor and a pressure pump, without using a soil transporting cart.

[0021] Also provided within the outer shell 11 are an erector 33 that assembles the segment rings 202, a plurality of shield jacks 34 that move the tunnel boring machine 100 forward, a first backfilling injection device 35 that injects backfilling material (grout material) between the inner peripheral surface of the excavation hole 204 excavated by the cutter head 20 and the outer peripheral surface of the segment ring 202, a roundness maintaining device 37 that maintains the shape of the segment ring 202, and a support section 32 that supports these devices. The roundness maintaining device 37 may be omitted.

[0022] The erector 33 can hold the arc-shaped segment pieces 206 and can move along the inner circumferential surface of the outer shell 11. The erector 33 assembles the multiple segment pieces 206 along the inner circumferential surface of the outer shell 11, thereby constructing a cylindrical segment ring 202.

[0023] An annular tail seal 11a that seals the gap between the outer shell 11 and the segment ring 202 is provided on the inner peripheral surface of the outer shell 11. The tail seal 11a prevents soil and water from entering the tunnel boring machine 100 through the gap between the outer shell 11 and the segment ring 202.

[0024] The first backfilling injection device 35 injects the backfilling material into the gap behind the tail seal 11a (between the excavation hole 204 and the segment ring 202) through the injection pipe 36. The injection pipes 36 are provided at predetermined intervals on the outer periphery of the outer shell 11, so that the backfilling material is filled over the entire area between the excavation hole 204 and the segment ring 202. The first backfilling injection device 35 may be provided on the inner periphery of the segment ring 202. In this case, the first backfilling injection device 35 injects the backfilling material into the gap behind the tail seal 11a through an opening (not shown) of the segment ring 202.

[0025] The shield jack 34 is a hydraulic jack having a cylinder and a rod, and a plurality of shield jacks 34 are provided at predetermined intervals in the circumferential direction inside the outer shell 11 (only one shield jack 34 is shown in FIG. 1). The cutter head 20 is pressed against the natural ground by a reaction force obtained from the segment ring 202 by extending the shield jack 34 while the tip end (-X end) of the rod protruding from the cylinder of the shield jack 34 is in contact with the side surface (+X end face) of the segment ring 202. In this way, the tunnel boring machine 100 uses the reaction force obtained by the shield jack 34 pressing the existing segment ring 202 as a propulsion force for excavating forward.

[0026] In the first embodiment, the outer shell 11 is formed of one cylindrical member, but it may be formed of two cylindrical members (a forward section and a rear section), with the forward section and the rear section being flexibly connected.

[0027] A trailing carriage is disposed behind the tunnel boring machine 100, which moves following the tunnel boring machine 100 as it excavates. The trailing carriage is used to transport a control device that controls the operation of the tunnel boring machine 100, a power supply device that supplies power to the tunnel boring machine 100, and equipment for constructing the shield tunnel TL.

[0028] The tunnel boring machine 100 rotates the cutter head 20, transports earth and sand using the screw conveyor 30, and extends the shield jack 34 to excavate the natural ground. An excavation hole 204 is excavated in the natural ground, and the shield tunnel TL is constructed by sequentially assembling the segment rings 202 along the inner circumferential surface of the excavation hole 204. A first backfilling injection device 35 injects backfilling material (grout material) into the gap generated between the inner circumferential surface of the excavation hole 204 and the outer circumferential surface of the segment ring 202, and the segment ring 202 is firmly bonded to the natural ground via the backfilling material.

[0029] Here, in this first embodiment, a natural ground exploration device 40 is provided near the cutter head 20 at the front end (end on the +X side) of the tunnel boring machine 100, on the -X side of the partition wall 12. Also, a second backfilling injection device 42 is provided near the natural ground exploration device 40 (near the -X side in FIG. 1).

[0030] 3(a) and 3(b) are enlarged and partially cross-sectional views of the natural ground exploration device 40 and its vicinity. As shown in FIG. 3(a), the natural ground exploration device 40 has a cylinder 52 as an exploration device main body and a rod 54. The cylinder 52 is fixed to the inner circumferential surface of the outer shell 11 via a flange portion 152 provided at the end on the +Z side, and the rod 54 protrudes from the outer circumferential portion of the outer shell 11 to the outside. The cylinder 52 does not have to be fixed to the outer shell 11 via the flange portion 152. For example, the cylinder 52 may be fixed to the outer shell 11 by a screw-in type. The pushing force of the rod 54 is steplessly adjusted by an adjustment device 58 (see FIG. 4). The adjustment device 58 is controlled by a control device 90 in FIG. 4.

[0031] The natural ground exploration device 40 is provided with a stroke meter 56. The stroke meter 56 is a linear displacement meter that measures the stroke amount (projection amount) of the rod 54 and outputs the measurement result to the control device 90.

[0032] In the first embodiment, the pushing force of the rod 54 in the natural ground exploration device 40 is set to a first pushing force (for example, a weak pushing force of about 1 N), and the rod 54 is protruded in the +Z direction as shown in Fig. 3(b). As a result, when the rod 54 moves in the +Z direction, it is found that there is a gap above the rod 54 (between the rod 54 and the natural ground). In addition, the stroke amount measured by the stroke meter 56 when the movement of the rod 54 stops means the depth of the gap (gap amount).

[0033] In addition, in the natural ground exploration device 40, when the pushing force of the rod 54 is gradually increased from the first pushing force, the rod 54 starts moving when a predetermined pushing force is reached. The stability of the natural ground (natural ground strength) can be determined from the pushing force (second pushing force) at the time when the rod 54 starts moving.

[0034] Therefore, the control device 90 in Figure 4 can determine whether or not there is a gap (cavity) in the ground, the depth of the cavity, and the stability of the ground (ground strength) based on the information (pushing force and stroke amount) obtained by the operation of the ground exploration device 40.

[0035] Returning to FIG. 1, the second backfilling injection device 42 is a device that supplies a chemical solution (backfilling material) to the ground to suppress subsidence of the ground. The chemical solution may be the same as the backfilling material (grout material) injected by the first backfilling injection device 35, for example, or may be another chemical solution. The control device 90 in FIG. 4 controls the second backfilling injection device 42 based on the identification result of the ground exploration device 40. The control device 90 also controls the first backfilling injection device 35 based on the identification result of the ground exploration device 40. Details of the control by the control device 90 will be described later.

[0036] 1 illustrates one natural ground exploration device 40 and a second backfilling injection device 42 provided in the vicinity of the natural ground exploration device 40, but in reality, a plurality of natural ground exploration devices 40 may be provided at predetermined intervals along the inner peripheral surface of the outer shell 11. Also, the second backfilling injection device 42 is capable of supplying chemical solution to the vicinity of each of the plurality of natural ground exploration devices 40.

[0037] Figure 4 is a block diagram showing a control system of the tunnel boring machine 100 according to the first embodiment. As shown in Figure 4, a control device 90 comprehensively controls the operation of each section in the tunnel boring machine 100. A memory 92 is connected to the control device 90, and the memory 92 stores a boring data table as shown in Figure 5(a) and a push-out force table as shown in Figure 5(b).

[0038] In the boring data table of FIG. 5(a), the "point number," the "distance from the starting shaft" of each point, and the "ground strength (N value) at depth D (m)" of each point are stored in association with each other. As shown in FIG. 5(c), each point is a point that is a predetermined distance (e.g., a distance about the width of one segment piece 206) away from the starting shaft along the extension direction of the shield tunnel TL. The N value at depth D (m) is the N value of each point (depth D (m)) measured by boring performed in advance. It can be said that the larger the N value, the more compact the soil is and the stronger the ground is.

[0039] The pushing force table in Fig. 5(b) is a table that shows, for each natural ground strength (N value), the pushing force of rod 54 at which rod 54 starts to move (at which rod 54 enters the natural ground) when the pushing force of rod 54 of natural ground exploration device 40 is gradually increased from a state in which rod 54 is pressed against the natural ground. The larger the N value, the tighter the soil is and the stronger the ground is, so the larger the N value, the greater the pushing force at which rod 54 starts to move. Note that the pushing force table is created based on the results of experiments conducted in advance.

[0040] (Operation of the tunnel boring machine 100) Next, the operation of the tunnel boring machine 100 will be described in detail along the flow charts of FIG. 6 and FIG. 7, with reference to other drawings as appropriate. For the sake of convenience, it is assumed that when the processing of FIG. 6 and FIG. 7 is started, a plurality of segment rings 202 are assembled along the inner circumferential surface of the excavation hole 204 as shown in FIG. 1, and a part of the shield tunnel TL has already been constructed. In the following, when the N value of the natural ground is 0 to 5, it means that the ground is soft and there is a risk of subsidence, so that it is necessary to immediately inject the chemical solution from the second backfilling injection device 42. In addition, when the N value of the natural ground is 5 to 20, it means that although there is a concern of subsidence, there is no need to immediately inject the chemical solution from the second backfilling injection device 42. In addition, when the N value of the natural ground is 20 or more, it means that there is no concern of subsidence, and it is not necessary to inject the chemical solution from the second backfilling injection device 42.

[0041] When the processing of Figure 6 is started, first, in step S10, the control device 90 performs excavation of one segment using the tunnel boring machine 100. The excavation of one segment will now be described with reference to Figures 8(a) to 9. Figure 8(a) shows a state in which a plurality of segment rings 202 have been assembled along the inner circumferential surface of an excavation hole 204 and part of a shield tunnel TL has been constructed.

[0042] From the state shown in Fig. 8(a), the control device 90 controls the motor 14 to rotate the cutter head 20 and extend the shield jack 34 as shown in Fig. 8(b) (see arrow E1 in Fig. 8(b)), thereby excavating the natural ground (see arrow E2 in Fig. 8(b)). In this excavation, the control device 90 extends the shield jack 34 by the width of one segment piece 206 in the X-axis direction. The control device 90 also operates the screw conveyor 30 to transport the soil and sand from the chamber CB.

[0043] Returning to FIG. 6, in the next step S12, the control device 90 waits until the excavation of one segment is completed. When the excavation of one segment is completed, the process proceeds to the next step S14, and the control equipment 90 starts assembling a new segment piece 206 using the erector 33, as shown in black in FIG. 9, to construct a cylindrical segment ring 202. During the construction of the segment ring 202, the control device 90 stops the motor 14 (cutter head 20) and the screw conveyor 30. The control device 90 also injects backfilling material from the first backfilling injection device 35 into the gap between the inner circumferential surface of the excavation hole 204 and the outer circumferential surface of the segment ring 202 (see the gray part in FIG. 9). The control device 90 can adjust the amount of backfilling material injected from the first backfilling injection device 35 to an appropriate amount based on the presence or absence of a cavity and its depth, which are identified in the process described below.

[0044] The process from step S16 onwards is to be performed before the end of the assembly of the segment pieces 206 in step S14. That is, the assembly of the segment pieces 206 and the process from step S16 onwards are performed simultaneously in parallel.

[0045] In step S16, the control device 90 controls the natural ground exploration device 40 to extend the rod 54 until it stops with a first pushing force (here, 1 N). At this time, if there is no cavity on the inner circumference of the excavation hole 204, the rod 54 stops at a position (stroke length La) as shown in Figure 10(a). On the other hand, if there is a cavity in the excavation hole 204, the rod 54 stops at a position (stroke length Lb) as shown in Figure 10(b).

[0046] Next, in step S18, the control device 90 judges whether the stroke when the rod 54 stops is larger than a normal gap. The normal gap is assumed to be the stroke length La in FIG. 10(a). If the judgment in this step S18 is negative (i.e., the case as in FIG. 10(a)), the process proceeds to step S22. On the other hand, if the judgment in step S18 is positive (i.e., the case as in FIG. 10(b)), the process proceeds to step S20. When the process proceeds to step S20, the control device 90 judges that a cavity exists. After that, the process proceeds to step S22.

[0047] When the process proceeds to step S22, the control device 90 controls the natural ground exploration device 40 to gradually increase the pushing force of the rod 54 up to the second pushing force (here, 10 N).

[0048] Next, in step S24, the control device 90 judges whether the rod 54 has started to move before the second pushing force is reached. Here, if the rod 54 has started to move, it means that the ground is unstable and loose, and there is a possibility that ground subsidence will occur unless measures are taken promptly. Therefore, if the judgment in step S24 is positive, the process proceeds to step S26, where the control device 90 controls the ground exploration device 40 to retract the rod 54 (see FIG. 3(a)). Then, in step S28, the control device 90 controls the second backfill injection device 42 to inject the chemical solution into the inner circumference of the excavation hole 204. Here, if the control device 90 judges that a cavity exists in step S20, it specifies the depth of the cavity from the stroke length of the rod 54 at the time when the rod stopped in step S18, and injects (injects) the amount of chemical solution according to the depth of the cavity. On the other hand, if step S20 has not been carried out (if it has not been determined that a cavity exists), the control device 90 injects a predetermined amount of chemical solution toward the inner circumferential surface of the excavation hole 204.

[0049] Next, the process proceeds to step S30, where the control device 90 judges whether or not to carry out the next excavation. If the judgment in step S30 is positive, the process returns to step S10. On the other hand, if the judgment in step S30 is positive (if the tunnel boring machine 100 has reached the arrival shaft (see FIG. 5(c))), all the processes in FIGS. 6 and 7 are terminated.

[0050] However, if the determination in step S24 is negative, that is, if the rod 54 does not start moving before the second pushing force (10N) is reached, the control device 90 proceeds to step S32 in FIG.

[0051] When the process proceeds to step S32 in FIG. 7, the control device 90 refers to the boring data table (FIG. 5(a)) in the memory 92 and judges whether the boring data at the depth D (m) of the current point is N value ≧ 20. If the judgment in step S32 is positive, the process proceeds to step S34, where the control device 90 refers to the pushing force table (FIG. 5(b)) to specify the pushing force corresponding to N value = 20 (40N in the case of FIG. 5(b)), and gradually increases the pushing force of the rod 54 to that pushing force. On the other hand, if the judgment in step S32 is negative, the process proceeds to step S36, where the control device 90 refers to the pushing force table (FIG. 5(b)) to specify the pushing force corresponding to the N value of the boring data, and gradually increases the pushing force of the rod 54 to that pushing force. For example, if the N value of the boring data is 10, the pushing force is gradually increased to 20N according to FIG. 5(b).

[0052] Next, in step S38, the control device 90 judges whether or not the rod 54 has started to move while the pushing force is being gradually increased as in step S34 or S36. If the judgment in step S38 is positive, the process proceeds to step S40, where the N value of the natural ground is identified from the pushing force when the rod 54 has started to move. For example, if the rod 54 has started to move when the pushing force is 10 N, the control device 90 refers to the pushing force table in Fig. 5(b) and identifies the N value of the natural ground as 5 (the N value corresponding to a pushing force of 10 N).

[0053] On the other hand, if the determination in step S38 is negative, i.e., if the rod 54 does not start moving even if the pushing force is gradually increased as in step S34 or S36, the process proceeds to step S42, where the N value of the natural ground is determined from the pushing force that was last set. For example, if the pushing force is gradually increased and the rod 54 does not start moving even when it finally reaches 20 N, the control device 90 refers to the pushing force table in Fig. 5(b) and determines that the N value of the natural ground is 10 (the N value corresponding to a pushing force of 20 N).

[0054] In the first embodiment, when the N value of the boring data is 20 or more, the pushing force of the rod 54 is gradually increased up to a pushing force (40 N) corresponding to N value=20 (step S34). If the rod 54 does not start moving even when the pushing force is increased to 40 N, it is clear that the ground is strong. Therefore, by setting the upper limit of the pushing force to 40 N, it is possible to shorten the processing time using the ground exploration device 40.

[0055] Thereafter, the process proceeds to step S44, where the control device 90 controls the natural ground exploration device 40 to retract the rod 54 until it reaches the state shown in FIG. 3(a).

[0056] Next, the process proceeds to step S46, where the control device 90 judges whether or not to carry out the next excavation. If the judgment in step S46 is positive, the process returns to step S10. On the other hand, if the judgment in step S46 is positive (if the tunnel boring machine 100 has reached the arrival shaft (see FIG. 5(c))), all the processes in FIGS. 6 and 7 are terminated.

[0057] As described above, by executing the processes of Figures 6 and 7, the tunnel boring machine 100 can excavate the tunnel one segment at a time, and while the segment pieces 206 are being assembled (while the tunnel boring machine 100 is stopped), a process (ground rock exploration process) can be performed to determine the presence or absence of cavities in the excavation hole 204, their depth, and the stability of the ground.

[0058] As described above in detail, according to the first embodiment, the natural ground exploration device 40 includes the cylinder 52 provided inside the tunnel boring machine 100 (outer shell 11), the rod 54 that can be inserted into and removed from the cylinder 52 and can be protruded from the outer periphery of the tunnel boring machine 100 (outer shell 11) to the outside, and the adjustment device 58 that adjusts the pushing force of the rod 54 from the cylinder 52. Then, under the instruction of the control device 90, the adjustment device 58 protrudes the rod 54 with a first pushing force (for example, 1N) and then protrudes the rod 54 with a second pushing force (a pushing force greater than 1N) greater than the first pushing force. This makes it possible to determine whether or not there is a cavity on the inner periphery of the excavation hole 204 facing the natural ground exploration device 40 and how large the cavity is (the amount of void) based on the movement of the rod 54 when the rod 54 is protruded with the first pushing force. In addition, the stability (ground strength) of the ground in the excavation hole 204 can be determined based on the movement of the rod 54 when the rod 54 is protruded by the second pushing force.

[0059] Furthermore, according to the first embodiment, the control device 90 determines the timing for injecting the backfilling material into the ground based on the stability of the ground (step S28 in FIG. 6). This makes it possible to reinforce the ground early when the ground is not stable and subsidence is likely to occur. Furthermore, the control device 90 determines the amount of backfilling material to be injected based on the size (depth) of the cavity, so that an appropriate amount of backfilling material can be injected to fill the cavity.

[0060] Furthermore, in this first embodiment, the cylinder 52 and the rod 54 are provided near the front end (the end on the +X side) of the tunnel boring machine 100. This makes it possible to quickly identify the amount of voids and the stability of the ground excavated by the cutter head 20, and to take measures early if the stability of the ground is low.

[0061] In the first embodiment, the control device 90 adjusts the pushing force based on boring data of the natural ground that has been previously performed (S34, S36). This allows the natural ground exploration device 40 to efficiently perform exploration processing. In the first embodiment, the first pushing force may be determined based on the boring data.

[0062] In the above first embodiment, the natural ground exploration device 40 is described as exploring the natural ground in the outer circumferential direction of the outer shell 11, but the present invention is not limited to this. For example, the natural ground exploration device 40 may explore the natural ground in front of the cutter head 20. In this case, the cylinder 52 is provided on the +X side of the partition wall 12, and the rod 54 is made to protrude from the opening 25 between the spoke portions 21 when exploring the natural ground.

[0063] In the above first embodiment, the second backfilling injection device 42 is provided on the -X side of the natural ground exploration device 40, but this is not limited thereto, and the second backfilling injection device 42 may be provided on the +X side, -Y side, +Y side, etc. of the natural ground exploration device 40.

[0064] In the above first embodiment, after injecting the chemical solution in step S28 of FIG. 6, a process of checking the strength of the natural ground (a process of checking whether the effect of the chemical solution has been exerted) may be performed using the natural ground exploration device 40.

[0065] (Modification) In the above-mentioned first embodiment, the control device 90 of the tunnel boring machine 100 controls the natural ground exploration device 40, but the present invention is not limited to this. FIG. 11 is a block diagram showing a control system according to a modification of the first embodiment. As shown in FIG. 11, in the modification, the tunnel boring machine 100 has a communication device 94, and the natural ground exploration device 40 is connected via the communication device 94. The natural ground exploration device 40 has the above-mentioned adjustment device 58 and stroke meter 56, an exploration control device 62, a memory 64, and a communication device 66. The exploration control device 62 acquires information on the timing of natural ground exploration transmitted from the control device 90 of the tunnel boring machine 100 via the communication device 66. Then, the exploration control device 62 executes the natural ground exploration process (the processes of steps S16 to S26 and S32 to S44 in FIG. 6 and FIG. 7) at the timing of natural ground exploration. It is assumed that the memory 64 stores the tables of FIG. 5(a) and FIG. 5(b). For this reason, the exploration control device 62 refers to each table stored in the memory 64 when exploring natural ground. Here, when the exploration control device 62 has performed the process of step S26, it outputs to the control device 90 of the tunnel boring machine 100 a notice that the process has been completed and an instruction to inject the chemical solution using the second backfilling injection device 42. In this case, the control device 90 uses the second backfilling injection device 42 to inject the chemical solution into the area where the natural ground strength is low (step S28). After performing the process of step S44, the exploration control device 62 outputs to the control device 90 of the tunnel boring machine 100 a notice that the process has been completed and information on the natural ground obtained as a result of the process via the communication device 66. In this case, the control device 90 of the tunnel boring machine 100 continues tunnel excavation or adjusts the amount of backfilling material injected from the first backfilling injection device 35 based on the information received from the exploration control device 62.

[0066] Second Embodiment The second embodiment will be described below with reference to Fig. 12(a) and Fig. 12(b). Fig. 12(a) shows a first natural rock exploration device 401 according to the second embodiment. The first natural rock exploration device 401 of the second embodiment includes a temperature sensor 71 and a moisture sensor 72 near the +Z end of the rod 54 in addition to the configuration of the natural rock exploration device 40 of the first embodiment.

[0067] The temperature sensor 71 detects the temperature of the natural ground and the temperature of the groundwater while the rod 54 is inserted into the natural ground. The detection results of the temperature sensor 71 are transmitted to the control device 90 (Fig. 4) and the exploration control device 62 (Fig. 11). The control device 90 and the exploration control device 62 can monitor changes in the rock mass that the tip of the rod 54 is in contact with based on the detection results of the temperature sensor 71, and can therefore determine whether or not to inject backfill material depending on the changes in the rock mass.

[0068] The moisture sensor 72 detects the amount of moisture on the surface of the natural ground. The detection result of the moisture sensor 72 is transmitted to the control device 90 (Fig. 4) and the exploration control device 62 (Fig. 11). Based on the detection result of the moisture sensor 72, the control device 90 and the exploration control device 62 can detect whether the tip of the rod 54 has come into contact with the surface of the natural ground, and therefore can identify the presence or absence of a cavity and the depth of the cavity according to the change in the amount of moisture and the stroke amount of the rod 54.

[0069] Furthermore, in this second embodiment, in addition to the configuration of the natural rock exploration device 40 of the first embodiment, an imaging device 73 and a laser rangefinder 74 may be provided at the upper end (+Z end) of the cylinder 52, as in the second natural rock exploration device 402 shown in Figure 12 (b).

[0070] The imaging device 73 captures images in the +Z direction, for example. The images captured by the imaging device 73 are transmitted to the control device 90 (FIG. 4) and the exploration control device 62 (FIG. 11). The control device 90 and the exploration control device 62 can identify the shape and size of the cavity by processing the captured images. Note that a lighting device may be provided near the imaging device 73, and the lighting device may be used to illuminate the natural ground when the imaging device 73 captures images.

[0071] The laser range finder 74 is for measuring the distance to the natural ground in the +Z direction by emitting a laser in the +Z direction, for example. The measurement result of the laser range finder 74 is transmitted to the control device 90 (FIG. 4) or the exploration control device 62 (FIG. 11). The control device 90 or the exploration control device 62 can specify the presence or absence of a cavity and the depth of the cavity based on the measurement result of the laser range finder 74. Instead of the process of step S16 in FIG. 6, the presence or absence of a cavity and the depth may be specified using the laser range finder 74, or both step S16 in FIG. 6 and the process using the laser range finder 74 may be executed, and the presence or absence of a cavity and the depth may be specified using both the results of each process. For example, the depth of the cavity may be specified using the laser range finder 74, and the process of step S16 in FIG. 6 may be executed from a state in which the tip (+Z end) of the rod 54 is brought close to the natural ground surface at high speed based on the depth of the cavity. This can shorten the processing time of step S16.

[0072] The temperature sensor 71, the moisture sensor 72, the imaging device 73, and the laser range finder 74 may have poor measurement accuracy or poor image quality due to dirt such as mud. Therefore, the rod 54 or the cylinder 52 may be provided with a liquid injection device for injecting a cleaning liquid (water) for cleaning the temperature sensor 71, the moisture sensor 72, the imaging device 73, and the laser range finder 74. Instead of the liquid injection device, a gas injection device for blowing away dirt and sand using gas may be provided. Also, a shutter may be provided to protect the temperature sensor 71, the moisture sensor 72, the imaging device 73, and the laser range finder 74 from dirt and sand.

[0073] In addition, the natural rock exploration device of this second embodiment may be equipped with all of the temperature sensor 71, moisture sensor 72, imaging device 73, and laser rangefinder 74 shown in Figures 12(a) and 12(b), or may be equipped with at least one of them.

[0074] In addition, when a predetermined pushing force is maintained when driving the rod 54, the driving current changes depending on the force (resistance of the ground) applied to the rod 54. Therefore, the driving current may be measured using an ammeter to measure the change in ground strength (change in ground hardness).

[0075] In the second embodiment, an injection nozzle for injecting the chemical solution supplied from the second backfilling injection device 42 may be provided near the tip (+Z end) of the rod 54. This makes it possible to inject the chemical solution from the tip of the rod 54 in step S28 of FIG. 6 when it is determined that the chemical solution needs to be injected immediately.

[0076] Third embodiment Next, a third embodiment will be described in detail with reference to Fig. 13 to Fig. 14(b). The third embodiment is characterized in that, as shown in Fig. 13, an X-drive mechanism 102 is provided in a tunnel boring machine 100 as a direction change device for driving the natural ground exploration device 40 in the X-axis direction.

[0077] The X-drive mechanism 102 has a plate-shaped holding member 104 that holds the natural ground exploration device 40, a support member 106 that supports the holding member 104 from the bottom (-Z side) while allowing the holding member 104 to move in the X-axis direction, and a slide jack 108 as a moving device that slides the holding member 104 in the X-axis direction.

[0078] A through hole 105 penetrating in the Z-axis direction is formed in the approximate center of the holding member 104, and the through hole 105 holds the cylinder 52 (flange portion 152) of the natural ground exploration device 40. An elongated hole 111 for passing the rod 54 through is formed in the outer shell 11 of the tunnel boring machine 100. The elongated hole 111 extends in the X-axis direction, so that even if the natural ground exploration device 40 moves in the X-axis direction with the rod 54 extended, there is no mechanical interference between the rod 54 and the outer shell 11.

[0079] A seal member 110 such as an O-ring is provided on the upper surface of the holding member 104. The seal member 110 prevents water or mud from the outside of the outer shell 11 from penetrating into the inside of the outer shell 11 through the long holes 111.

[0080] The slide jack 108 has a cylinder and a rod that is movable in the X-axis direction relative to the cylinder. When the rod extends (moves in the +X direction), the holding member 104 and the natural ground exploration device 40 move in the +X direction relative to the outer shell 11. When the rod contracts (moves in the -X direction), the holding member 104 and the natural ground exploration device 40 move in the -X direction relative to the outer shell 11.

[0081] In this third embodiment, while the tunnel boring machine 100 is performing excavation operations (i.e., while moving in the +X direction), the natural ground exploration device 40 is used to determine the presence or absence and depth of cavities in the natural ground, and to perform processing to determine the stability of the natural ground.

[0082] Fig. 14(a) and Fig. 14(b) are diagrams for explaining the processing using the natural ground exploration device 40 of Fig. 13. The control device 90 of the tunnel boring machine 100, while performing the excavation operation, executes the processing of steps S16 to S26 and S32 to S44 of Fig. 6 and Fig. 7 by making the moving speed of the rod of the shield jack 34 (i.e., the moving speed of the tunnel boring machine 100 in the direction of the arrow D1 (+X direction) in Fig. 14(a)) the same as the moving speed of the rod of the slide jack 108 (i.e., the moving speed of the holding member 104 in the direction of the arrow D2 (-X direction) in Fig. 14(a)). In this case, by setting the moving direction and moving speed of the natural ground exploration device 40 as described above, the natural ground exploration device 40 maintains a stopped state relative to the natural ground as shown in Fig. 14(b). As a result, even while the tunnel boring machine 100 is excavating, it is possible to identify the presence or absence of cavities in the natural ground, their depth, and the stability of the natural ground using the natural ground exploration device 40. This eliminates the restriction that processing using the natural ground exploration device 40 can only be performed when the tunnel boring machine 100 is not excavating, making it possible to shorten the construction period for tunnel excavation.

[0083] In the above third embodiment, a case has been described in which processing is performed using natural ground exploration device 40 during the excavation operation of tunnel boring machine 100, but the present invention is not limited to this. For example, while tunnel boring machine 100 is not performing excavation operation (while stopped), processing using natural ground exploration device 40 may be performed, and processing may be repeated in which processing using natural ground exploration device 40 is performed again after moving a predetermined distance in the X-axis direction. In this way, processing to identify the presence or absence of cavities in the natural ground, their depths, and natural ground strength may be performed at multiple locations.

[0084] (Modification) In the above third embodiment, the natural ground exploration device 40 is described as a device having a rod 54 and a cylinder 52. However, this is not limited to this. As shown in FIG. 15, the natural ground exploration device 40 may be a device having a laser rangefinder 74 at its upper end instead of the rod 54 or the cylinder 52.

[0085] 15, for example, while the tunnel boring machine 100 is stopped, the natural ground exploration device 40 is moved in the X-axis direction and the distance to the opposing natural ground is measured using the laser range finder 74. This makes it possible to measure the XZ cross-sectional shape of the natural ground (the XZ cross-sectional shape of the cavity).

[0086] Also, for example, while the tunnel boring machine 100 is stopped, the natural ground exploration device 40 is moved in the X-axis direction and the laser of the laser range finder 74 is scanned around the X-axis to measure the distance to the natural ground. This makes it possible to measure the three-dimensional shape of the natural ground (the three-dimensional shape of the cavity).

[0087] Also, for example, while the tunnel boring machine 100 is excavating, the natural ground exploration device 40 may be moved in the X-axis direction and the distance to the opposing natural ground may be measured using the laser range finder 74. This makes it possible to measure the XZ cross-sectional shape of the natural ground (the XZ cross-sectional shape of the cavity) while the tunnel boring machine 100 is excavating. Furthermore, while the tunnel boring machine 100 is excavating, the natural ground exploration device 40 may be moved in the X-axis direction and the laser of the laser range finder 74 may be scanned around the X-axis to measure the distance to the natural ground. This makes it possible to measure the three-dimensional shape of the natural ground (the three-dimensional shape of the cavity) while the tunnel boring machine 100 is excavating.

[0088] As described above, by measuring the cross-sectional shape and three-dimensional shape of the ground, the amount of backfill material to be injected into the ground from the first backfill injection device 35 and the second backfill injection device 42 can be adjusted to an appropriate amount.

[0089] In addition, in each of the above embodiments and variations, if the control device 90 or the exploration control device 62 determines that a cavity exists or that the ground strength is low, it may output this to an external device (for example, a PC used by an operator) and issue a warning.

[0090] The tunnel boring machine 100 in each of the above embodiments and modified examples is a so-called mud pressure type shield machine. Alternatively, the tunnel boring machine 100 may be a so-called mud pressure type shield machine equipped with a mud water supply and discharge device that supplies and discharges mud water to and from the chamber CB to carry out excavated soil and sand accumulated in the chamber CB to the rear of the tunnel boring machine 100.

[0091] The above-described embodiment is a preferred example of the present invention, but the present invention is not limited to this embodiment and can be modified in various ways without departing from the scope of the present invention. [Explanation of symbols]

[0092] 40. Ground exploration equipment 52 Cylinder (main body of the exploration device) 54 Rod 58 Adjustment device 62 Exploration control device (control device) 71 Temperature Sensor 72 Moisture Sensor 73 Imaging Device 74 Laser rangefinder 100 Tunnel Boring Machine 102 X drive mechanism (change device) 108 Slide jack (moving device)

Claims

1. A natural ground exploration device that is installed on a tunnel boring machine to explore the strength of natural ground, An exploration device main body provided inside the tunnel boring machine; A rod that can be inserted into and removed from the exploration device body and can be protruded from an outer periphery of the tunnel boring machine to the outside; an adjustment device for adjusting the pushing force of the rod from the exploration device body; a control device that protrudes the rod with a first pushing force adjusted by the adjustment device, and then protrudes the rod with a second pushing force adjusted by the adjustment device and greater than the first pushing force.

2. The natural ground exploration device according to claim 1 , wherein the control device specifies a void amount of the natural ground by using the first pushing force, and specifies a stability of the natural ground based on the second pushing force.

3. The natural ground exploration device according to claim 2, wherein the control device determines the timing for injecting backfilling filler into voids in the natural ground based on the stability of the natural ground, and determines the amount of backfilling filler to be injected based on the amount of voids in the natural ground.

4. The natural ground exploration device according to claim 1 , wherein the exploration device body and the rod are provided near a front end portion of the tunnel boring machine.

5. The natural ground exploration device according to claim 1 , wherein the control device adjusts at least one of the first pushing force and the second pushing force based on boring data of the natural ground that has been previously performed.

6. The natural ground exploration device according to claim 1 , further comprising a change device for changing a positional relationship between a front end portion of the tunnel boring machine and the exploration device main body and the rod.

7. The natural rock exploration device according to claim 1 , wherein the rod is provided with at least one of a temperature sensor and a moisture sensor.

8. The natural rock exploration device according to claim 1 , wherein the exploration device body is provided with at least one of a laser range finder and an imaging device.

9. The natural ground exploration device according to claim 8 , further comprising an injection device that injects a cleaning fluid onto at least one of the laser range finder and the imaging device.

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