Natural ground exploration device

Abstract

To accurately explore a condition of the ground.SOLUTION: A natural ground exploration device is a natural ground exploration device 40 that is installed in a tunnel boring machine 100 to explore 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 an outer periphery of the tunnel boring machine, an adjustment device that adjusts a 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 that is adjusted by the adjustment device and is greater than the first pushing force.SELECTED DRAWING: Figure 1

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 ahead of the shield machine in the direction of travel or directly above the shield machine. Conventionally, an exploration system is known that acquires information on the natural ground from multiple locations near the tunnel face and determines the stability of the natural ground based on this information (see, for example, Patent Document 1).

[0003] According to the technology described in Patent Document 1, the stability of the ground is determined based on the measurement results of an upper exploration device installed on 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 be retracted 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] Japanese Patent Application Laid-Open No. 2011-196068 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the upper exploration device in Patent Document 1 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 that can accurately explore 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 to explore the strength of the natural ground, and comprises an exploration device main body provided inside the tunnel boring machine, a rod that is retractable into and 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 that is adjusted by the adjustment device and is greater than the first pushing force.

[0008] The second natural ground exploration device of the present invention is a natural ground exploration device that is installed on a tunnel boring machine to explore the strength of the natural ground, and comprises a measuring device that is provided on the tunnel boring machine and measures at least one of the void volume of the natural ground and the stability of the natural ground, a moving device that moves the measuring device relative to the tunnel boring machine, and a control device that controls 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. [Effects 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 explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a tunnel boring machine according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing the cutter head as viewed from the +X direction. [Figure 3] 3(a) and 3(b) are enlarged, partially cross-sectional 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. [Figure 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] 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 a normal gap. [Figure 11] FIG. 11 is a block diagram showing a control system according to a modification 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 ground 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 modified example of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

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

[0012] Figure 1 is a cross-sectional view showing the schematic configuration of a tunnel boring machine 100 according to a first embodiment. In Figure 1, hatching indicating cross sections has been omitted to avoid cluttering 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 constructs a shield tunnel TL (tunnel) by excavating the ground (natural ground) to form a borehole 204 and assembling segment rings 202 to cover the inner wall of the borehole 204. Note that the tunnel boring machine 100 may be a machine other than a shield tunneling machine, for example, a boring machine installed at the end 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 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 of the traveling direction being the +Y direction and the right side of the traveling direction 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] Tunnel boring machine 100 is an earth pressure type shield machine used in an earth pressure shield tunneling method, and as shown in Figure 1, has a cylindrical body 10. Body 10 has a cylindrical outer shell 11 extending along the axial direction of the shield tunnel TL (the X-axis direction in Figure 1), a cutter head 20 that is driven to rotate in front of outer shell 11, and a partition wall 12 that is provided within outer shell 11 and arranged opposite to the -X side of cutter head 20. The cross-sectional shape of 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. Note that the arrangement of the plurality of cutter bits 24 is one example. Furthermore, the spoke portions 21 may be provided with a plurality of types of cutter bits.

[0017] In the cutter head 20, openings 25 are formed between adjacent spoke portions 21. The earth and sand 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 stirring rods) for stirring the excavated earth and sand 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 shown in FIG. 4 controls the operation of the motors 14 to thereby control the direction and speed of rotation of the cutter head 20.

[0020] A screw conveyor 30 is provided within the outer shell 11 of the tunnel boring machine 100 for transporting excavated soil accumulated 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 rotation of the screw transports the excavated soil in the chamber CB to the rear of the partition wall 12. The excavated soil transported to the rear by the screw conveyor 30 is transported within the shield tunnel TL by an soil transport cart (not shown) and discharged to the ground. It is to be noted that the excavated soil may be transported to the ground using an earth discharge system that combines a conveyor such as a belt conveyor or screw conveyor, a pressure pump, etc., without using an earth transport 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 backfill injection device 35 that injects backfill 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 rings 202, a roundness maintaining device 37 that maintains the shape of the segment rings 202, and a support section 32 that supports these devices. Note that the roundness maintaining device 37 may be omitted.

[0022] The erector 33 is capable of gripping the arc-shaped segment pieces 206 and is also capable of moving 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 is provided on the inner peripheral surface of the outer shell 11 to seal the gap between the outer shell 11 and the segment ring 202. 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 backfilling material into the gap behind the tail seal 11a (between the borehole 204 and the segment ring 202) via an 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 borehole 204 and the segment ring 202. The first backfilling injection device 35 may also be provided on the inner circumferential surface 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 via an opening (not shown) in the segment ring 202.

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

[0026] In the first embodiment, the outer shell 11 is made up of one cylindrical member, but it may also be made up of two cylindrical members (a forward section and aft section), with the forward section and the aft section connected in a flexible manner.

[0027] A trailing carriage is positioned 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. A borehole 204 is excavated in the natural ground, and the shield tunnel TL is constructed by sequentially assembling segment rings 202 along the inner circumferential surface of the borehole 204. A first backfill injection device 35 injects backfill material (grout material) into the gaps that occur between the inner circumferential surface of the borehole 204 and the outer circumferential surfaces of the segment rings 202, and the segment rings 202 are firmly bonded to the natural ground via the backfill material.

[0029] Here, in the 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, 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 the 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 outward from the outer circumferential portion of the outer shell 11. Note that 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 in a screw-type manner. The pushing force of the rod 54 is continuously adjusted by an adjustment device 58 (see FIG. 4). The adjustment device 58 is controlled by a control device 90 shown 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 determined that there is a gap above the rod 54 (between the rod 54 and the natural ground). Furthermore, the stroke amount measured by the stroke meter 56 when the movement of the rod 54 stops indicates 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 to move when a predetermined pushing force is reached. The pushing force (second pushing force) at the time when the rod 54 starts to move can be used to determine the stability of the natural ground (natural ground strength).

[0034] Therefore, the control device 90 in Figure 4 can determine whether there is a void (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 backfill injection device 42 is a device that supplies a chemical solution (backfill material) to the ground to suppress subsidence of the ground. The chemical solution may be the same as the backfill material (grout material) injected by the first backfill injection device 35, for example, or may be another chemical solution. The control device 90 in FIG. 4 controls the second backfill injection device 42 based on the identification results of the ground exploration device 40. The control device 90 also controls the first backfill injection device 35 based on the identification results of the ground exploration device 40. Details of the control by the control device 90 will be described later.

[0036] 1 shows one natural ground exploration device 40 and a second backfilling injection device 42 provided near 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 circumferential surface of the outer shell 11. The second backfilling injection device 42 is also 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 the 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 of the tunnel boring machine 100. A memory 92 is connected to the control device 90, and the memory 92 stores a boring data table such as that shown in Figure 5(a) and a push-out force table such as that shown in Figure 5(b).

[0038] The boring data table in Figure 5(a) stores the "location number," the "distance from the starting shaft" of each location, and the "ground strength (N value) at depth D (m)" of each location, all associated with each other. As shown in Figure 5(c), each location is a location that is a predetermined distance (for example, a distance approximately 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 location (depth D (m)) measured by boring performed in advance. The larger the N value, the more compact the soil and the stronger the ground.

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

[0040] (Operation of tunnel boring machine 100) Next, the operation of the tunnel boring machine 100 will be described in detail with reference to the flowcharts in Figures 6 and 7 and other drawings as appropriate. For ease of explanation, it is assumed that when the processing in Figures 6 and 7 is started, multiple segment rings 202 have been assembled along the inner circumferential surface of the borehole 204 as shown in Figure 1, and a portion of the shield tunnel TL has already been constructed. In the following, when the N-value of the natural ground is 0 to 5, this means that the ground is soft and there is a risk of subsidence, so it is necessary to immediately inject the chemical solution from the second backfill injection device 42. Furthermore, when the N-value of the natural ground is 5 to 20, it means that there is a risk of subsidence, but it is not necessary to immediately inject the chemical solution from the second backfill injection device 42. Furthermore, when the N-value of the natural ground is 20 or more, it means that there is no risk of subsidence, so it is not necessary to inject the chemical solution from the second backfill injection device 42.

[0041] When the processing of Figure 6 is started, first, in step S10, the control device 90 excavates 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 the borehole 204, and part of the shield tunnel TL has been constructed.

[0042] From the state shown in Figure 8(a), the control device 90 controls the motor 14 to rotate the cutter head 20, and as shown in Figure 8(b), extends the shield jack 34 (see arrow E1 in Figure 8(b)), and excavates the natural ground (see arrow E2 in Figure 8(b)). During 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 earth 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, where the control device 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. Note that when constructing this 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 backfill material from the first backfill injection device 35 into the gap that occurs between the inner surface of the excavation hole 204 and the outer surface of the segment ring 202 (see the gray part in FIG. 9 ). Note that the control device 90 can adjust the amount of backfill material injected from the first backfill injection device 35 to an appropriate amount based on the presence or absence and depth of a cavity identified in a process described below.

[0044] The processes from step S16 onwards are to be carried out before the completion of the assembly of the segment pieces 206 in step S14. That is, the assembly of the segment pieces 206 and the processes from step S16 onwards are carried out simultaneously in parallel.

[0045] In step S16, the control device 90 controls the natural ground exploration device 40 to extend the rod 54 with a first pushing force (here, 1 N) until the rod 54 stops. At this time, if there is no cavity on the inner periphery 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 determines 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 determination in step S18 is negative (i.e., the case is as in FIG. 10(a)), the process proceeds to step S22. On the other hand, if the determination in step S18 is positive (i.e., the case is as in FIG. 10(b)), the process proceeds to step S20. When the process proceeds to step S20, the control device 90 determines that a cavity exists. Thereafter, 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 determines whether the rod 54 has started to move before the second pushing force is reached. If the rod 54 has started to move, it means that the ground is unstable and loose, and that ground subsidence may occur unless measures are taken promptly. Therefore, if the determination in step S24 is affirmative, the process proceeds to step S26, where the control device 90 controls the natural 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 periphery of the excavation hole 204. If the control device 90 determines in step S20 that a cavity exists, it determines the depth of the cavity from the stroke length of the rod 54 at the time the rod stopped in step S18, and injects (injects) an amount of chemical solution corresponding 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 liquid toward the inner circumferential surface of the borehole 204.

[0049] Next, the process proceeds to step S30, in which the control device 90 determines whether or not to carry out the next excavation. If the determination in step S30 is positive, the process returns to step S10. On the other hand, if the determination in step S30 is positive (if the tunnel boring machine 100 has reached the arrival shaft (see Figure 5(c))), all of the processing in Figures 6 and 7 is 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 determines whether the boring data at the depth D (m) of the current point satisfies the N value ≧20. If the determination in step S32 is affirmative, the process proceeds to step S34, where the control device 90 refers to the pushing force table (FIG. 5(b)) to identify the pushing force corresponding to the N value=20 (40 N 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 determination 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 identify 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 20 N, as shown in FIG. 5(b).

[0052] Next, in step S38, the control device 90 determines whether the rod 54 has started to move while the pushing force is being gradually increased as in step S34 or S36. If the determination in step S38 is positive, the process proceeds to step S40, where the N value of the natural ground is determined 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 determines that the N value of the natural ground is 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, that is, if the rod 54 does not start moving even after gradually increasing the pushing force 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 finally reaches 20 N but the rod 54 does not start moving, 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 the 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, in step S46, the control device 90 determines whether or not to carry out the next excavation. If the determination in step S46 is positive, the process returns to step S10. On the other hand, if the determination in step S46 is positive (if the tunnel boring machine 100 has reached the arrival shaft (see Figure 5(c))), all of the processing in Figures 6 and 7 is 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 identify 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 comprises a cylinder 52 provided inside the tunnel boring machine 100 (outer shell 11), a rod 54 that is retractable into and retractable from the cylinder 52 and that can protrude from the outer periphery of the tunnel boring machine 100 (outer shell 11), and an adjustment device 58 that adjusts the pushing force of the rod 54 from the cylinder 52. Then, under the command of the control device 90, the adjustment device 58 protrudes the rod 54 with a first pushing force (for example, 1 N) and then protrudes the rod 54 with a second pushing force (greater than 1 N) that is greater than the first pushing force. As a result, it is possible to determine whether or not a cavity exists on the inner circumferential surface of the excavation hole 204 facing the natural ground exploration device 40 and the size of the cavity (void volume) based on the movement of the rod 54 when the rod 54 is protruded with the first pushing force. Furthermore, the stability of the ground (ground strength) of 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 backfill 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 unstable and prone to subsidence. Furthermore, the control device 90 determines the amount of backfill material to be injected based on the size (depth) of the cavity, so that an appropriate amount of backfill material can be injected to fill the cavity.

[0060] Furthermore, in the first embodiment, the cylinder 52 and the rod 54 are provided near the front end (end on the +X side) of the tunnel boring machine 100. This makes it possible to quickly identify the amount of cavities and 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 conducted (S34, S36). This allows the natural ground exploration device 40 to efficiently perform the exploration process. Note that in the first embodiment, the first pushing force may be determined based on the boring data.

[0062] In the first embodiment, the natural ground exploration device 40 is described as exploring the natural ground in the outer peripheral 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 first embodiment, the second backfill injection device 42 is provided on the -X side of the natural ground exploration device 40, but this is not limited to this, and the second backfill 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 first embodiment, after injecting the chemical solution in step S28 of FIG. 6, a process of checking the strength of the 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] (Variation) In the 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 this modification, the tunnel boring machine 100 has a communication device 94, and the natural ground exploration device 40 is connected to the communication device 94 via the communication device 94. The natural ground exploration device 40 has the adjustment device 58 and stroke meter 56 described above, 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. The exploration control device 62 then executes natural ground exploration processing (the processing of steps S16 to S26 and S32 to S44 in FIGS. 6 and 7) at the timing of natural ground exploration. It is assumed that the memory 64 stores the tables shown in FIGS. 5(a) and 5(b). For this reason, the exploration control device 62 refers to each table stored in memory 64 when conducting natural ground exploration. Here, when the exploration control device 62 has performed the processing of step S26, it outputs to the control device 90 of the tunnel boring machine 100 a notice that the processing has ended and an instruction to inject 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 chemical solution into areas where the natural ground strength is low (step S28). Furthermore, after performing the processing of step S44, the exploration control device 62 outputs to the control device 90 of the tunnel boring machine 100 a notice that the processing has ended and information about the natural ground obtained as a result of the processing 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 Figures 12(a) and 12(b). Figure 12(a) shows a first natural rock exploration device 401 according to the second embodiment. In addition to the configuration of the natural rock exploration device 40 of the first embodiment, the first natural rock exploration device 401 of the second embodiment is equipped with a temperature sensor 71 and a moisture sensor 72 near the +Z end of the rod 54.

[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 sent to the control device 90 (Fig. 4) and the exploration control device 62 (Fig. 11). Based on the detection results of the temperature sensor 71, 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, 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 results of the moisture sensor 72 are sent to the control device 90 (Fig. 4) and the exploration control device 62 (Fig. 11). Based on the detection results 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 its depth according to the change in moisture amount and the stroke amount of the rod 54.

[0069] Furthermore, in this second embodiment, in addition to the configuration of the natural ground 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 ground 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 an illumination device may be provided near the imaging device 73, and the illumination device may be used to illuminate the natural ground when the imaging device 73 captures images.

[0071] The laser rangefinder 74 measures the distance to the natural ground in the +Z direction by emitting a laser beam in the +Z direction, for example. The measurement results of the laser rangefinder 74 are 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 determine the presence or absence of a cavity and its depth based on the measurement results of the laser rangefinder 74. Note that instead of the process of step S16 in FIG. 6 , the presence or absence of a cavity and its depth may be determined using the laser rangefinder 74. Alternatively, both step S16 in FIG. 6 and the process using the laser rangefinder 74 may be performed, and the presence or absence of a cavity and its depth may be determined using the results of both processes. For example, the depth of the cavity may be determined using the laser rangefinder 74, and the process of step S16 in FIG. 6 may be performed after the tip (+Z end) of the rod 54 is brought close to the surface of the natural ground at high speed based on the depth of the cavity. This reduces the processing time of step S16.

[0072] Note that the temperature sensor 71, moisture sensor 72, imaging device 73, and laser rangefinder 74 may have poor measurement accuracy or poor image quality due to dirt, etc. Therefore, a liquid injection device for injecting cleaning liquid (water) for cleaning the temperature sensor 71, moisture sensor 72, imaging device 73, and laser rangefinder 74 may be provided on the rod 54 or cylinder 52. Note that instead of a liquid injection device, a gas injection device for blowing away soil and sand using gas may be provided. Also, a shutter may be provided to protect the temperature sensor 71, moisture sensor 72, imaging device 73, and laser rangefinder 74 from soil and sand.

[0073] The natural ground 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] When a predetermined pushing force is maintained while driving the rod 54, the driving current changes depending on the force (resistance of the ground) acting on the rod 54. Therefore, the driving current may be measured using an ammeter to measure changes in ground strength (changes 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 Figures 13 to 14(b). As shown in Figure 13, the third embodiment is characterized in that an X-drive mechanism 102 is provided in the tunnel boring machine 100 as a 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 underside (-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 approximately the center of the holding member 104, and the cylinder 52 (flange portion 152) of the natural ground exploration device 40 is held in this through hole 105. An elongated hole 111 for passing the rod 54 therethrough 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 elongated 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 of cavities in the natural ground and their depth, and to perform processing to determine the stability of the natural ground.

[0082] Figures 14(a) and 14(b) are diagrams for explaining processing using the natural ground exploration device 40 of Figure 13. The control device 90 of the tunnel boring machine 100, while performing an excavation operation, sets 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 arrow D1 (+X direction) in Figure 14(a)) to be 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 arrow D2 (-X direction) in Figure 14(a)), and executes the processing of steps S16 to S26 and S32 to S44 in Figures 6 and 7. 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 remains stopped relative to the natural ground, as shown in Figure 14(b). As a result, 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, even while the tunnel boring machine 100 is excavating. This eliminates the restriction that processing using the natural ground exploration device 40 can only be performed when the machine 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 using natural ground exploration device 40 is performed 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 the machine may then move a predetermined distance in the X-axis direction and perform processing using natural ground exploration device 40 again, repeating this processing. In this way, processing to identify the presence or absence of cavities in the natural ground, their depths, and natural ground strength can be performed at multiple locations.

[0084] (Variation) In the third embodiment, the natural ground exploration device 40 is described as a device having a rod 54 and a cylinder 52, but this is not limited thereto. As shown in FIG. 15, the natural ground exploration device 40 may be a device having a laser rangefinder 74 at the upper end thereof 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 rangefinder 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 laser rangefinder 74 may be used to measure the distance to the opposing natural ground. 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 rangefinder 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 variants, 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 modifications is a so-called mud pressure shield machine. Alternatively, the tunnel boring machine 100 may be a so-called mud pressure shield machine equipped with a mud water supply and discharge device that supplies and discharges mud water to and from the chamber CB, thereby carrying out excavated earth and sand that has 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 and can be modified in various ways without departing from the spirit of the present invention. [Explanation of symbols]

[0092] 40 Ground exploration equipment 52 Cylinder (detection device body) 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 ground exploration device that is installed on a tunnel boring machine and that explores the strength of ground, an exploration device main body provided inside the tunnel boring machine; a rod that can be retracted into and out of the exploration device body and can be protruded from the outer periphery of the tunnel boring machine; an adjustment device for adjusting the pushing force of the rod from the exploration device body; and a control device that extends the rod with a first pushing force adjusted by the adjustment device, and then extends the rod with a second pushing force that is adjusted by the adjustment device and is greater than the first pushing force.

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

3. 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. 2. The natural ground exploration device according to claim 1, wherein the exploration device body and the rod are provided near a front end 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 the positional relationship between a front end of the tunnel boring machine and the exploration device body and the rod.

7. The natural ground 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 ground exploration device according to claim 1 , wherein the exploration device main 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.

10. A ground exploration device that is installed on a tunnel boring machine and that explores the strength of ground, 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 that moves the measuring device relative to the tunnel boring machine; a control device that controls the moving device to move the measuring device in a direction opposite to that of the tunnel boring machine at the same speed as that of the tunnel boring machine; A ground exploration device equipped with:

11. The natural ground exploration device according to claim 10, wherein the measurement device has a rod that can protrude from the outer periphery of the tunnel boring machine and that comes into contact with the natural ground.

12. The natural ground exploration device according to claim 10, wherein the measurement device is a laser range finder.

13. The natural ground exploration device according to any one of claims 10 to 12, wherein the control device sequentially positions the measurement device at a plurality of positions while the tunnel boring machine is not moving, and instructs the measurement device to perform measurements at each position.

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