Obstacle contact state acquiring system and obstacle contact state acquiring method

Abstract

To provide an obstacle contact state acquiring system capable of effectively acquiring an obstacle contact state without causing damage on a sensor.SOLUTION: An obstacle contact state acquiring system 10 is applied to a shield excavation machine 30 including a cylindrical skin plate 31, a cutter head 40 provided at a front end of the skin plate 31, and a barrier wall 50 arranged to be separated from and opposite to the cutter head 40 in the skin plate 31 so as to acquire a contact state of an obstacle excavated with the cutter head 40. The obstacle contact state acquiring system comprises: an AE sensor 20 installed at a position where AE waves propagated from the natural ground are receivable, in a portion not contacting with a working face of the shield excavation machine 30; and obstacle contact state acquiring sections 100, 200, 210, 220, 230, 240, 250, 260 acquiring the contact state of the obstacle on the basis of an AE signal acquired by the AE sensor 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an obstacle contact state acquisition system and an obstacle contact state acquisition method, and in particular to a technique suitable for acquiring the contact state of an obstacle being excavated in shield construction using a shield tunneling machine. [Background technology]

[0002] In recent years, there has been an increase in shield tunneling construction in which the shield tunneling machine directly excavates piles and retaining walls that impede tunneling. There have also been an increasing number of cases in which the shield tunneling machine encounters unexpected obstacles while tunneling. If the cutter bit or other parts are damaged by the excavation of a high-strength obstacle, the shield tunneling machine will be unable to tunnel, resulting in delays in the construction period. For this reason, it is important in shield tunneling construction to appropriately obtain the contact state of the obstacle being excavated and to appropriately reflect the obtained results in construction management and construction measures.

[0003] For example, Patent Document 1 discloses a technology in which a vibration sensor is provided on the front side of a cutter head, which outputs an electrical signal corresponding to the soil type upon contact with the face, and the soil type is determined based on the output of the vibration sensor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-10090 Summary of the Invention [Problem to be solved by the invention]

[0005] In the technology described in Patent Document 1, the vibration sensor is configured to directly contact the tunnel face. Therefore, if a high-strength obstacle such as a metal object is exposed at the tunnel face while the shield machine is excavating, the vibration sensor may be damaged by contact with the obstacle.

[0006] In addition, in the technology described in Patent Document 1, a spring, lever, etc. for abutting the vibration sensor against the face is provided on the front of the cutter head. Therefore, if excavation soil or the like adheres to and accumulates on the spring or lever, the vibration sensor cannot be reliably brought into contact with the face, which may lead to a decrease in detection accuracy. In addition, if the vibration sensor or spring is damaged, a worker must access the front of the cutter head to replace them, which is time-consuming and labor-intensive.

[0007] The technology disclosed herein has been made in consideration of the above circumstances, and aims to provide a technology that can effectively obtain the contact state of an obstacle to be excavated without causing damage to the sensor. [Means for solving the problem]

[0008] The obstacle contact state acquisition system of the present disclosure comprises: An obstacle contact state acquisition system (10) that is applied to a shield machine (30) including a cylindrical skin plate (31), a cutter head (40) provided at a front end of the skin plate (31), and a partition wall (50) disposed within the skin plate (31) facing and spaced apart from the cutter head (40), the obstacle contact state acquisition system (10) acquiring a contact state of an obstacle excavated by the cutter head (40), an AE sensor (20) installed at a position in a portion of the shield machine (30) that does not contact the tunnel face, the position being capable of receiving AE waves propagating from the natural ground; and an obstacle contact state acquisition unit (100, 200, 210, 220, 230, 240, 250, 260) that acquires the contact state of the obstacle based on the AE signal acquired by the AE sensor (20). It is characterized by:

[0009] In another aspect of the obstacle contact state acquisition system of the present disclosure, The AE sensor (20) It is preferable that the insulating layer 21 is installed inside the cutter spokes (45) of the cutter head (40) or on the rear surface of the partition wall (50) opposite to the cutter head (40).

[0010] In another aspect of the obstacle contact state acquisition system of the present disclosure, The obstacle contact state acquisition unit (100, 200, 210, 220, 230, 240) An obstacle determination process is performed to determine whether or not an obstacle is present in the ground to be excavated based on the maximum amplitude (MA) and / or energy (EN) of the AE signal acquired by the AE sensor (20) during excavation of the ground. It is preferable.

[0011] In another aspect of the obstacle contact state acquisition system of the present disclosure, The obstacle contact state acquisition unit (100, 200, 210, 220, 230, 250) When it is determined that an obstacle is present by the obstacle determination process, a type determination process is further executed to determine the type of the obstacle based on the maximum amplitude (MA) and / or energy (EN) of the AE signal of the obstacle. It is preferable.

[0012] In another aspect of the obstacle contact state acquisition system of the present disclosure, The obstacle contact state acquisition unit (100, 200, 210, 220, 230, 260) An excavation load calculation process is performed to calculate an excavation load, which is a load applied when the shield machine (30) excavates the target natural ground, based on the maximum amplitude (MA) and / or energy (EN) of the AE signal acquired by the AE sensor (20) while excavating the natural ground. It is preferable.

[0013] Another aspect of the obstacle contact state acquisition system of the present disclosure is to The shield tunneling machine further includes an excavation speed setting unit (270) that reduces the excavation speed of the shield tunneling machine (30) as the excavation load calculated by the excavation load calculation process increases. It is preferable.

[0014] Another aspect of the obstacle contact state acquisition system of the present disclosure is to The shield machine further includes an excavation feasibility determination unit (280) that determines whether or not the shield machine (30) is capable of excavating the obstacle based on the excavation load calculated by the excavation load calculation process. It is preferable.

[0015] The obstacle contact state acquisition method of the present disclosure includes: 1. An obstacle contact state acquisition method that is applied to a shield machine (30) including a cylindrical skin plate (31), a cutter head (40) provided at a front end of the skin plate (31), and a partition wall (50) disposed within the skin plate (31) facing and spaced apart from the cutter head (40), and that acquires a contact state of an obstacle excavated by the cutter head (40), comprising: an AE sensor (20) is installed at a position that is not in contact with the face of the shield machine (30) and can receive AE waves propagated from the natural ground; The contact state of the obstacle is acquired based on the AE signal acquired by the AE sensor (20). It is characterized by:

[0016] In the above description, in order to facilitate understanding of the present disclosure, the symbols used in the embodiments are added in parentheses to components corresponding to the embodiments, but each component is not limited to the embodiment defined by the symbol. Effect of the Invention

[0017] According to the obstacle contact state acquisition system and obstacle contact state acquisition method disclosed herein, the contact state of an obstacle in an excavation target can be effectively acquired without causing damage to the sensor. [Brief description of the drawings]

[0018] [Figure 1]1 is a schematic vertical cross-sectional view showing a shield machine to which an obstacle contact state acquisition system according to an embodiment of the present invention is applied. [Diagram 2] FIG. 2 is a schematic front view showing a cutter head of a shield machine according to the present embodiment. [Diagram 3] FIG. 2 is a schematic cross-sectional view showing a cutter spoke of the shield machine according to the present embodiment. [Figure 4] 13 is a schematic vertical cross-sectional view showing a shield machine to which a modified obstacle contact state acquisition system is applied. FIG. [Diagram 5] FIG. 2 is a schematic perspective view showing a fixing jig for mounting the AE sensor according to the present embodiment. [Figure 6] FIG. 2 is a schematic diagram illustrating an example of a hardware configuration of an information processing device according to the present embodiment. [Figure 7] FIG. 2 is a schematic diagram showing an example of a software configuration of the information processing device according to the present embodiment. [Figure 8] FIG. 4 is a schematic diagram showing an example of analysis data (maximum amplitude of an AE signal) according to the present embodiment. [Figure 9] FIG. 4 is a schematic diagram showing an example of analysis data (energy of an AE signal) according to the present embodiment. [Figure 10] FIG. 4 is a schematic diagram showing a look-up table for calculating an excavation load according to the present embodiment. [Figure 11] FIG. 4 is a schematic diagram showing a look-up table for setting an excavation speed according to the present embodiment. [Figure 12] 5 is a flowchart illustrating a processing routine for acquiring an obstacle contact state according to the present embodiment. [Figure 13] FIG. 13 is a schematic diagram showing an example of a software configuration of an information processing device according to a modified example. [Figure 14] 13 is a flowchart illustrating a processing routine for acquiring an obstacle contact state according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an obstacle contact state acquisition system and an obstacle contact state acquisition method according to the present embodiment will be described with reference to the accompanying drawings.

[0020] [Overall configuration] FIG. 1 is a schematic vertical cross-sectional view showing a shield machine 30 to which an obstacle contact state acquisition system 10 according to this embodiment is applied.

[0021] The shield machine 30 constructs a shield tunnel T by assembling multiple segments S on the inner wall of a hole excavated in the natural ground or bedrock. Hereinafter, the excavation direction of the shield machine 30 will be referred to as the "forward direction," and the opposite direction to the excavation direction will be referred to as the "rearward direction."

[0022] The shield tunneling machine 30 comprises a cylindrical skin plate 31, a cutter head 40 arranged at the front end of the skin plate 31, and a partition wall 50 arranged rearward of the cutter head 40 within the skin plate 31 and facing the cutter head 40 at a distance.

[0023] The rotary joint 41 of the cutter head 40 is rotatably supported by the partition wall 50 via a bearing or the like (not shown). In addition, the rotating ring 32 is rotatably supported by the partition wall 50 via a bearing or the like (not shown). The rotating ring 32 is connected to the cutter head 40 via a connecting beam 33 so as to be rotatable together with the cutter head 40.

[0024] A plurality of drive motors 35 capable of transmitting rotational force to the rotating ring 32 via a gear mechanism (not shown) or the like are provided inside the skin plate 31. When the rotating ring 32 is rotated by the rotational power of the drive motors 35, the cutter heads 40 rotate while being pressed against the natural ground, thereby excavating the natural ground.

[0025] A chamber 55 is defined between the cutter head 40 and the partition wall 50 inside the skin plate 31. Soil excavated by the cutter head 40 is filled into the chamber 55 through the opening 49 (see FIG. 2) of the cutter head 40. An additive is added to the soil in the chamber 55 by an additive device (not shown). The additive turns the soil in the chamber 55 into mud in a plastic flow state.

[0026] The shield machine 30 shown in Fig. 1 is a so-called mud pressure shield machine that generates mud pressure by filling a chamber 55 with mud and excavating, and excavates with the mud pressure counteracting the earth pressure at the face. Note that the shield machine 30 to which the obstacle contact state acquisition system 10 of the present disclosure is applied is not limited to the mud pressure shield machine shown in the example, and may be a muddy water shield excavator.

[0027] A screw conveyor 60, a jack 64, and an erector 68 are provided inside the skin plate 31. The screw conveyor 60 discharges mud from inside the chamber 55. A plurality of jacks 64 are arranged at predetermined intervals in the circumferential direction on the inner surface of the skin plate 31. The jacks 64 cause the shield machine 30 to excavate forward by receiving a reaction force from the existing segments S. The erector 68 holds the segments S and rotates in the circumferential direction to assemble the segments S into a ring shape.

[0028] 1 indicates the backfill material injected between the outer periphery of the segment S and the inner wall of the excavation hole by a backfill injection device (not shown). A tail seal 69 is provided on the rear end side of the skin plate 31 to prevent the backfill material BM, groundwater, etc. from infiltrating through the gap between the skin plate 31 and the existing segment S.

[0029] [Cutter head] The cutter head 40 includes an outer ring 42, an inner ring 43, a central cylinder 44, a plurality of cutter spokes 45, a center cutter 46, a plurality of cutter bits 47, and a plurality of auxiliary cutter spokes 48 (see FIG. 2). Note that the inner ring 43 and the auxiliary cutter spokes 48 may not be included depending on the diameter of the cutter head 40, etc.

[0030] The outer circumferential ring 42 is formed into a ring shape with approximately the same diameter as the skin plate 31. The inner circumferential ring 43 is formed into a ring shape with a smaller diameter than the outer circumferential ring 42. The central tube portion 44 is formed into a cylindrical shape with both ends closed (except for the portions through which cables, piping, etc. are inserted). The outer circumferential ring 42, the inner circumferential ring 43, and the central tube portion 44 are arranged concentrically. The connecting beam 33 is connected to the rear end of the inner circumferential ring 43.

[0031] The rotary joint 41 is connected to the rear surface of the central cylinder 44. In addition, the cutter spokes 45 are connected to the outer circumferential surface of the central cylinder 44. The central cylinder 44, the rotary joint 41, and the cutter spokes 45 are formed to be hollow, and a space for routing the cable C1 and the like is provided inside.

[0032] As shown in Fig. 2, a plurality of cutter spokes 45 are provided radially from the central tube portion 44 to the outer peripheral ring 42. A plurality of cutter bits 47 are attached to the front and side surfaces of the cutter spokes 45. A plurality of auxiliary cutter spokes 48 are provided at approximately the middle positions between adjacent cutter spokes 45 in the circumferential direction. The auxiliary cutter spokes 48 are provided from the inner peripheral ring 43 to the outer peripheral ring 42. A plurality of openings 49 are formed between the outer peripheral ring 42, the inner peripheral ring 43, the cutter spokes 45, and the auxiliary cutter spokes 48 to allow excavated soil to pass through.

[0033] As shown in Fig. 3, the cutter spokes 45 are formed, for example, in a rectangular frame shape having a hollow cross-sectional structure, and include a front plate 45A, a pair of side plates 45B, 45C, and a rear plate 45D. The cutter spokes 45 are not limited to a rectangular frame shape, and may have a circular cross-sectional shape, etc. As shown in Figs. 1 and 3, the AE sensor 20 is attached to the surface (rear surface) of the front plate 45A opposite the face. As shown in Fig. 4, the AE sensor 20 can also be attached to the surface (rear surface) of the partition wall 50 opposite the chamber 55.

[0034] [AE sensor] Here, AE is an abbreviation of Acoustic Emission, and is an elastic wave (hereinafter referred to as AE wave) emitted from an object as a primary phenomenon when cracks, wear, etc. occur in the object. The AE sensor 20 is equipped with a piezoelectric element (not shown), receives the AE wave emitted from the object, and outputs it as a voltage signal (hereinafter referred to as AE signal) by the piezoelectric element. In other words, the AE sensor 20 can detect the AE signal as a pre-stage sign of damage, etc. occurring in the object. Therefore, by using the AE sensor 20, it is possible to detect obstacles in the natural ground earlier than when an acceleration sensor or vibration sensor that detects secondary phenomena is used.

[0035] In the example shown in Fig. 1, the AE sensor 20 is attached so as to be located radially outward within the cutter spokes 45. By arranging the AE sensor 20 radially outward and away from the rotary joint 41 within the cutter spokes 45 in this way, it is possible to effectively reduce the influence of rotational noise emitted from the bearings of the rotary joint 41, etc. Furthermore, by arranging the AE sensor 20 within the cutter spokes 45 closest to the tunnel face of the shield tunneling machine 30, it is also possible to receive AE waves propagated from the natural ground with high sensitivity. Furthermore, by arranging the AE sensor 20 within the cutter spokes 45, it is possible to reliably prevent the AE sensor 20 from being damaged by contact with the tunnel face.

[0036] In the modification shown in FIG. 4, the AE sensor 20 is attached so as to be located radially outside the bulkhead 50. By arranging the AE sensor 20 radially outside the bulkhead 50 in this way, it is possible to effectively reduce the influence of the driving sound of the drive motor 35, the gear meshing sound, and the like. In addition, by arranging the AE sensor 20 on the bulkhead 50, which is relatively close to the face inside the skin plate 31, it is possible to effectively receive AE waves propagated from the natural ground. In addition, by arranging the AE sensor 20 on the bulkhead 50, it is possible to reliably prevent the AE sensor 20 from being damaged by contact with the face. In addition, by arranging the AE sensor 20 on the bulkhead 50, it is possible for workers to easily perform the installation work and replacement work of the AE sensor 20.

[0037] In the example shown in Fig. 4, the drive motor 35 is provided at a radially intermediate position of the partition 50, but depending on the type of shield machine, the drive motor 35 may be disposed on the outer periphery or center of the partition 50. When the drive motor 35 is disposed on the outer periphery of the partition 50, the AE sensor 20 may be attached to the center of the partition 50. When the drive motor 35 is disposed on the center of the partition 50, the AE sensor 20 may be attached to the radially outer side of the partition 50, as in the example shown in Fig. 4.

[0038] In order to increase the detection sensitivity of obstacles in the natural ground, it is preferable that the AE sensor 20 uses a resonant type AE sensor having a resonant peak in a predetermined frequency band. For example, when the type of obstacle (typically metal, concrete, etc.) in the natural ground can be known in advance, it is preferable that the AE sensor 20 uses a resonant type AE sensor having a resonant peak in the frequency band of the AE waves emitted by the obstacle. On the other hand, there are cases where excavation is performed without knowing the type of obstacle in the natural ground. In such cases, the AE sensor 20 may use a resonant type AE sensor having a resonant peak in a frequency band of several tens of kHz to a hundred kHz, or it is also possible to install multiple resonant type AE sensors having different resonant peaks.

[0039] The AE sensor 20 is not limited to a resonance type AE sensor, and depending on the state of the ground to be excavated and the type of obstacles, a so-called wideband AE sensor capable of measurement in a wide band may also be used.

[0040] [Fixing fixture] FIG. 5 is a schematic perspective view showing a fixing jig 90 for mounting the AE sensor 20 on the front plate 45A of the cutter spoke 45 or the rear surface of the partition wall 50. As shown in FIG.

[0041] The AE sensor 20 includes a cylindrical case 21, a disk-shaped wave-receiving surface 22 that covers the opening of the case 21, and a connector 23 provided on the case 21. A piezoelectric element (not shown) for converting the AE wave into an AE signal is provided on the rear surface of the wave-receiving surface 22. A cable C1 (see FIGS. 1 and 4) is connected to the connector 23.

[0042] The fixture 90 includes an approximately L-shaped angle bar 91 having a first plate portion 91A and a second plate portion 91B that intersect with each other at approximately a right angle, a holder 92, and a pair of magnets 95, 96 fixed to the angle bar 91. The holder 92 is attached to the first plate portion 91A via a spring 94 and is provided so as to be movable in the surface direction of the second plate portion 91B. The holder 92 is approximately rectangular parallelepiped-shaped and has a recess 93 for receiving the AE sensor 20. The opening width of the recess 93 is formed to be larger than the outer diameter of the case 21. The case 21 of the AE sensor 20 is inserted into the recess 93 so that the wave receiving surface 22 faces away from the bottom of the recess 93.

[0043] When the case 21 of the AE sensor 20 is inserted into the recess 93, the pair of magnets 95, 96 face each other with a space between them, sandwiching the wave-receiving surface 22. When the magnets 95, 96 are attracted to the front plate 45A of the cutter spoke 45 or the rear surface of the partition wall 50, the AE sensor 20 is pressed against these surfaces by the biasing force of the spring 94 via the holder 92. In this state, the wave-receiving surface 22 of the AE sensor 20 faces the face. In other words, the AE sensor 20 can be easily installed at a desired installation position by an operator simply fixing the magnets 95, 96 of the fixing jig 90 to the front plate 45A of the cutter spoke 45 or the rear surface of the partition wall 50 by magnetic force.

[0044] [Information processing device] 1 and 4 again, an amplifier 70 is connected to the AE sensor 20 via a cable C1. In the example shown in FIG. 1, the cable C1 is routed through the cutter spokes 45, the central cylinder portion 44, and the internal space of the rotary joint 41. The amplifier 70 amplifies the analog AE signal input from the AE sensor 20 and converts the amplified analog signal into a digital signal. Note that if the AE sensor 20 has a built-in amplifier, the amplifier 70 may be omitted. The amplifier 70 is connected to the information processing device 100 via a cable C2.

[0045] The information processing device 100 is a device for determining whether an obstacle is present in the natural ground in front of the shield tunneling machine 30 based on the AE signal input from the amplifier 70, and is configured, for example, by a computer, a server, etc. The location where the information processing device 100 is installed is not limited to inside the shield tunneling machine 30 in the illustrated example, and it may be installed in a remote office away from the site. The information processing device 100 can also be configured by a mobile terminal such as a tablet terminal or a smartphone.

[0046] The information processing device 100 includes various programs, a storage device, etc. The various programs included in the information processing device 100 mainly execute a determination process for determining whether an obstacle exists in the natural ground. The storage device of the information processing device 100 stores data, etc., used for processing by the various programs.

[0047] [Hardware configuration of information processing device] 6 is a schematic diagram showing an example of a hardware configuration of an information processing device 100 according to this embodiment. The information processing device 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, and a RAM (Random Access Memory) 103. The CPU 101, the ROM 102, and the RAM 103 form a so-called microcomputer. The information processing device 100 also includes an auxiliary storage device 104, a network IF 105, an operation device 107, and a display device 108.

[0048] The CPU 101 executes various programs stored in the auxiliary storage device 104. The ROM 102 is a non-volatile memory and stores data and the like necessary for the CPU 101 to execute the various programs stored in the auxiliary storage device 104. The RAM 102 is a volatile memory and provides a working area into which the various programs stored in the auxiliary storage device 104 are expanded when the CPU 101 executes the various programs. The auxiliary storage device 104 is an auxiliary storage device that stores various programs and data and the like used when the various programs are executed.

[0049] The network IF 105 is a communication device for the information processing device 100 to communicate with other devices via a network. The operation device 107 is an input device for an on-site worker to give various instructions and settings to the information processing device 100. The display device 108 is a display device for displaying various display screens such as analysis data, obstacle determination results, and excavation load, which will be described later.

[0050] [Software configuration of information processing device] FIG. 7 is a schematic diagram showing an example of the software configuration of the information processing device 100 according to the present embodiment.

[0051] 7, the information processing device 100 includes a measurement data acquisition unit 200, a measurement data storage unit 210, an analysis processing unit 220, an analysis data storage unit 230, an obstacle determination unit 240, a type determination unit 250, a machine learning model 255, an excavation load calculation unit 260, and an excavation speed setting unit 270. The measurement data acquisition unit 200, the measurement data storage unit 210, the analysis processing unit 220, the analysis data storage unit 230, the obstacle determination unit 240, the type determination unit 250, and the excavation load calculation unit 260 are examples of the obstacle contact state acquisition unit of the present disclosure.

[0052] The measurement data acquisition unit 200 acquires the AE signals sequentially input from the AE sensor 20 via the amplifier 70 while the shield machine 30 is excavating, and stores the acquired AE signals as measurement data in the measurement data storage unit 210. Here, the measurement data includes, in addition to the AE signal detected by the AE sensor 20, the measurement time when the AE sensor 20 detected the AE signal, the excavation speed and torque when the AE signal was detected, etc. The measurement data acquisition unit 200 stores the AE signal acquired from the AE sensor 20 in the measurement data storage unit 210 by linking it to the measurement time, excavation speed, torque, etc.

[0053] The analysis processing unit 220 calculates the maximum amplitude (the amplitude value from the center of the AE waveform to the maximum displacement) and energy (the integrated value of the AE waveform) as characteristics of the AE signal based on the measurement data stored in the measurement data storage unit 210. The analysis processing unit 220 also associates the calculated maximum amplitude and energy of the AE signal with the measurement time, excavation speed, torque, etc., and stores them in the analysis data storage unit 230 as analysis data. The analysis data stored in the analysis data storage unit 230 can be displayed on the display device 108. The display device 108 may display the analysis data in real time while the shield machine 30 is excavating, or may display it in response to the operation of the operating device 107 by the worker.

[0054] 8 and 9 are schematic diagrams for explaining an example of analysis data calculated based on measurement data acquired during the excavation of the shield machine 30. The vertical axis in FIG. 8 indicates the maximum amplitude of the AE signal, and the vertical axis in FIG. 9 indicates the energy of the AE signal. The horizontal axis in FIG. 8 and FIG. 9 indicates the elapsed time. In FIG. 8 and FIG. 9, the solid lines indicate analysis data for the section where the shield machine 30 is excavating the natural ground (hereinafter referred to as "natural ground section analysis data"), and the dashed lines indicate analysis data for the section where the shield machine 30 starts from a shaft and excavates the shaft wall (hereinafter referred to as "shaft wall section analysis data"). Note that, depending on the shield construction, there are cases where the shield machine 30 does not start from a shaft, but for convenience, the following will explain an example where the shield machine 30 starts from a shaft.

[0055] 8 and 9, the shaft wall section analysis data shows larger values ​​for both maximum amplitude and energy than the natural ground section analysis data. In other words, it can be seen that the higher the strength of the excavation target, the larger the maximum amplitude and energy of the AE signal. The obstacle contact state acquisition system 10 of this embodiment acquires the state of the natural ground of the excavation target based on such characteristics of the AE signal.

[0056] Referring again to Figure 7, the obstacle determination unit 240 performs obstacle determination to determine whether or not an obstacle is present in the ground based on analysis data calculated from current measurement data acquired sequentially during excavation by the shield tunneling machine 30 and analysis data stored in the analysis data memory unit 230 (preferably the most recent analysis data).

[0057] Specifically, the obstacle determination unit 240 compares the maximum amplitude MA of the AE signal of the current analysis data (hereinafter, current maximum amplitude MAn) with the maximum amplitude MA of the AE signal of the immediately preceding analysis data (hereinafter, immediately preceding maximum amplitude MAn-1) and determines whether a first obstacle condition (MAn-MAn-1≧A1) is satisfied in which the current maximum amplitude MAn is greater than the immediately preceding maximum amplitude MAn-1 by a predetermined amount A1 or more. The obstacle determination unit 250 also compares the energy EN of the AE signal of the current analysis data (hereinafter, current energy ENn) with the energy EN of the AE signal of the immediately preceding analysis data (hereinafter, immediately preceding energy ENn-1) and determines whether a second obstacle condition (ENn-ENn-1≧A2) is satisfied in which the current energy ENn is greater than the second immediately preceding energy ENn-1 by a predetermined amount A2 or more. Here, the predetermined amounts A1 and A2 are not particularly limited, but may be set in consideration of values ​​that can remove the effects of noise and the like contained in the AE signal, for example.

[0058] When at least one of the first obstacle condition or the second obstacle condition is satisfied, the obstacle determination unit 240 determines that "an obstacle is present" in the ground to be excavated. On the other hand, when neither the first obstacle condition nor the second obstacle condition is satisfied, the obstacle determination unit 240 determines that "no obstacle is present" in the ground to be excavated. The obstacle determination unit 240 successively displays the determination results on the display device 108. This enables the worker at the site to know in real time whether or not an obstacle is present in the ground to be excavated.

[0059] The type determination unit 250 executes type determination to determine the type (e.g., metal, concrete, etc.) of an object determined as an obstacle by the obstacle determination unit 240 using a machine learning model 255. The machine learning model 255 is a model that has been trained in advance based on teacher data that associates the type of an object with the maximum amplitude and energy of an AE signal emitted by the object. In the illustrated example, the machine learning model 255 is provided in the information processing device 100, but may be provided in an external server device or the like that can communicate via the network IF 105.

[0060] The type determination unit 250 inputs the maximum amplitude MA and energy EN of the analysis data of an object determined to be an obstacle by the obstacle determination unit 240 to the machine learning model 255, and acquires a result output from the machine learning model 255, thereby determining the type of the obstacle. Furthermore, the type determination unit 250 displays the determined type of obstacle on the display device 108. This enables a worker at the site to grasp in real time the type of obstacle present in the natural ground to be excavated.

[0061] The excavation load calculation unit 260 calculates the excavation load DL, which is the load when the shield machine 30 excavates the ground to be excavated (if an object determined as an obstacle by the obstacle determination unit 240 exists, the obstacle), based on the AE signal of the current analysis data. The method of calculating the excavation load DL is not particularly limited, and for example, it can be calculated based on a model formula including the maximum amplitude MA, energy EN, excavation speed, etc. of the current analysis data as input values. In addition, the calculation of the excavation load DL is not limited to the method using the model formula, and for example, it is possible to store a plurality of lookup tables TB1_1, TB1_2, . . . TB1_n, which are defined for each excavation speed, of the relationship between the maximum amplitude MA of the AE signal emitted from the target object and the excavation load DL as shown in FIG. 10 in the storage unit of the information processing device 100, and calculate the excavation load DL by using the lookup tables. Specifically, in the lookup tables TB1_1, TB1_2, . . . TB1_n, the excavation load DL is set to increase as the maximum amplitude MA increases. The excavation load calculation unit 260 calculates the excavation load DL required to excavate the ground (including obstacles) to be excavated by referring to lookup tables TB1_1, TB1_2, ... TB1_n based on the maximum amplitude MA of the current analysis data and the excavation speed, etc.

[0062] The lookup tables TB1_1, TB1_2, . . . TB1_n may use a table that defines the relationship between the energy EN of the AE signal and the excavation load DL. In addition, when the type determination unit 250 can determine the type of the obstacle, the excavation load calculation unit 260 may calculate the excavation load DL based on the type determination result.

[0063] The excavation speed setting unit 270 sets an optimum excavation speed for the shield machine 30 to excavate the natural ground (including obstacles) to be excavated. Specifically, the storage unit of the information processing device 100 stores a lookup table TB2 that defines the relationship between the maximum amplitude MA of the AE signal emitted from the excavation target and the optimum excavation speed V, as shown in Fig. 11. In the lookup table TB2, the excavation speed V is set to decrease as the maximum amplitude MA increases.

[0064] The excavation speed setting unit 270 first determines whether the excavation load DL calculated by the excavation load calculation unit 260 is equal to or lower than a predetermined threshold load DL V Here, it is determined whether the threshold load DL V For example, the excavation load DL may be set based on a load that allows the shield machine 30 to reliably excavate the excavation target even if the shield machine 30 maintains the current excavation speed. V In the following cases, it is determined that there is no abnormality in the excavation load. In this case, the excavation speed setting unit 270 is not set. In other words, the current excavation speed is maintained.

[0065] On the other hand, the excavation speed setting unit 270 sets the excavation load DL to the threshold load DL V If it is greater than , the excavation load is judged to be large, in other words, it is judged that excavation is impossible at the current excavation speed. In this case, the excavation speed setting unit 270 determines the optimal excavation speed V by referring to the lookup table TB2 based on the maximum amplitude MA of the current analysis data. In other words, the excavation speed V is set to be slower and the excavation torque is reduced as the strength of the excavation target increases. This makes it possible to effectively prevent damage to the cutter bit 47. By preventing damage to the cutter bit 47, it is possible to prevent the shield machine 30 from becoming unable to excavate, and it is also possible to reliably prevent delays in the construction period.

[0066] The lookup table TB2 may use a table that defines the relationship between the energy EN of the AE signal and the optimum excavation speed V. Furthermore, when the type determination unit 250 can determine the type of obstacle, the excavation speed setting unit 270 may determine the optimum excavation speed V based on the type determination result.

[0067] Next, a processing routine for acquiring an obstacle contact state executed by the CPU 101 of the information processing device 100 will be described based on the flowchart shown in Fig. 12. This routine is started, for example, when the shield tunneling machine 30 starts from a vertical shaft. Note that, depending on the shield construction, there are cases where the machine does not start from a vertical shaft. In such cases, this routine can start processing from step S120 described below. This routine will be described taking as an example a case where the presence of an obstacle in the natural ground is known in advance through a preliminary survey or the like, and the shield tunneling machine 30 is equipped with a cutter bit 47 capable of cutting the obstacle.

[0068] In step S100, the information processing device 100 acquires measurement data based on the AE signal transmitted from the AE sensor 20 while the shield machine 30 is excavating the shaft wall. Next, in step S105, the information processing device 100 calculates and stores shaft wall section analysis data based on the measurement data acquired in step S100.

[0069] In step S110, the information processing device 100 determines whether the shield machine 30 has penetrated the shaft wall. Whether the shield machine 30 has penetrated the shaft wall may be determined based on the excavation distance since the shield machine 30 started moving, or may be determined based on whether the maximum amplitude MA and / or energy EN of the AE signal has decreased compared to when the shaft wall was excavated. If the shield machine 30 has penetrated the shaft wall (Yes), the information processing device 100 proceeds to processing of step S120. On the other hand, if the shield machine 30 has not penetrated the shaft wall (No), the information processing device 100 returns to processing of step S100.

[0070] In step S120, the information processing device 100 acquires measurement data based on the AE signal transmitted from the AE sensor 20 while the shield machine 30 is excavating the natural ground (including obstacles) to be excavated. Next, in step S125, the information processing device 100 calculates analysis data based on the measurement data acquired in step S120.

[0071] In step S130, the information processing device 100 stores the analysis data calculated in step S125 as the immediately preceding analysis data.

[0072] In step S140, the information processing device 100 acquires current measurement data based on the AE signal transmitted from the AE sensor 20 while the shield machine 30 is excavating the ground (including obstacles) to be excavated. Next, in step S145, the information processing device 100 calculates current analysis data based on the measurement data acquired in step S140.

[0073] In step S150, the information processing device 100 executes an obstacle determination for comparing the current analysis data calculated in step S145 with the immediately preceding analysis data stored in step S130. Specifically, it is determined whether or not at least one of a first obstacle condition that the current maximum amplitude MAn is greater than the immediately preceding maximum amplitude MAn-1 by a predetermined amount A1 or more, or a second obstacle condition that the current energy ENn is greater than the immediately preceding energy ENn-1 by a predetermined amount A2 or more, is satisfied.

[0074] If at least one of the first obstacle condition or the second obstacle condition is satisfied (Yes), the information processing device 100 proceeds to the process of step S160 and determines that an obstacle is present in the ground to be excavated. On the other hand, if neither the first obstacle condition nor the second obstacle condition is satisfied (No), the information processing device 100 proceeds to the process of step S155 and determines that no obstacle is present in the ground to be excavated, and returns to the process of step S120.

[0075] When the information processing device 100 determines in the process of step S160 that an obstacle exists in the ground to be excavated, the information processing device 100 proceeds to the process of step S162. In step S162, the information processing device 100 executes a type determination to determine the type of the obstacle based on the maximum amplitude MA and energy EN of the current analysis data acquired in step S140, and proceeds to the process of step S166.

[0076] In step S166, the information processing device 100 calculates an excavation load DL, which is a load when excavating the natural ground (including obstacles) to be excavated, based on the current analysis data acquired in step S140.

[0077] In step S170, the information processing device 100 calculates the excavation load DL calculated in step S166 and a predetermined threshold load DL V Specifically, the excavation load DL of the target object is compared with a predetermined threshold load DL V If the digging load DL of the target object is greater than the predetermined threshold load DL V In the following case (No), the information processing device 100 proceeds to the process of step S180, determines that there is no abnormality in the excavation load, and returns to the process of step S120.

[0078] If it is determined in the process of step S175 that the excavation load is large, the information processing device 100 proceeds to the process of step S176, executes an excavation speed setting process for setting an optimum excavation speed V for the shield machine 30 to excavate the obstacle, and then returns to the process of step S120. After that, until construction of the shield tunnel T is completed, the information processing device 100 repeatedly executes each of the processes from step S140 onwards.

[0079] According to the present embodiment described above in detail, the AE sensor 20 is installed on the rear surface of the front plate 45A of the cutter spoke 45 or on the rear surface of the bulkhead 50. That is, the AE sensor 20 is configured to be installed at a position where it can effectively receive AE waves without coming into contact with the working face. This makes it possible to reliably prevent the AE sensor 20 from being damaged by contact with an obstacle or the like. Furthermore, by using the AE sensor 20 to detect obstacles, it becomes possible to detect obstacles in the natural ground earlier than when an acceleration sensor, vibration sensor, or the like that detects secondary phenomena is used.

[0080] Furthermore, according to this embodiment, the information processing device 100 calculates the excavation load DL when the shield machine 30 excavates the target natural ground (including obstacles) based on the maximum amplitude MA and energy EN of the AE signal acquired by the AE sensor 20, and sets an optimum excavation speed V according to the excavation load DL. In other words, the system is configured so that the excavation speed V suitable for excavating obstacles, etc. can be reflected in excavation management. This makes it possible to reliably prevent damage to the cutter bit 47 due to the excavation of obstacles, and effectively prevents delays in construction due to the inability of the shield machine 30 to excavate.

[0081] Here, as a conventional technique using an acceleration sensor, for example, JP 09-209688 A proposes a technique of attaching an acceleration sensor as a sonic sensor to the bulkhead of a shield tunneling machine and monitoring the ground condition based on sound (hearing) and waveform signals (hereinafter, conventional example 1). Also, JP 2019-027121 A proposes a technique of installing a vibration acceleration sensor on a cutter bit and judging the soil quality of the ground at the face based on the acceleration waveform (hereinafter, conventional example 2).

[0082] In the case of conventional example 1, workers must constantly pay attention to the drilling sound, which is labor-intensive, and there is also the problem that individual differences in hearing affect the judgment results.In addition, in the case of conventional example 2, there is a problem that the acceleration waveform cannot be detected unless an obstacle comes into contact with the cutter bit on which the vibration acceleration sensor is installed, and further, if the cutter bit on which the vibration acceleration sensor is installed is damaged, the acceleration waveform cannot be detected.

[0083] In contrast, according to the obstacle contact state acquisition system 10 of this embodiment, since an obstacle is detected using the AE sensor 20 that detects AE waves in a high frequency range higher than the audible range, there is no need for workers to pay attention to drilling sounds as in the conventional example 1, and the labor of workers can be reliably reduced. In addition, since the AE sensor 20 is provided in a part that does not contact the face, such as inside the cutter spokes 45 or the rear surface of the bulkhead 50, it is possible to effectively prevent detection failure due to damage as in the conventional example 2.

[0084] [Variations] For example, in the flowchart shown in Fig. 12, an example is described in which the presence of an obstacle in the natural ground is known in advance by a preliminary survey or the like, but there may be cases in which an unexpected obstacle is present in the natural ground to be excavated. In such a case, as shown in Fig. 13, the information processing device 100 may further include an excavation feasibility determination unit 280 that determines whether or not the obstacle can be cut based on the excavation load DL calculated by the excavation load calculation unit 260.

[0085] Fig. 14 is a flowchart of a modified example illustrating a processing routine for acquiring an obstacle contact state when the information processing device 100 includes the excavation possibility determination unit 280. Note that each process of steps S100 to S180 shown in Fig. 14 is similar to the process shown in Fig. 12, and therefore description thereof will be omitted.

[0086] When the information processing device 100 determines in the process of step S175 that the excavation load is large, the information processing device 100 proceeds to the process of step S200 and determines whether or not the excavation load DL calculated in step S166 exceeds a predetermined upper limit load DLm. If the excavation load DL does not exceed the upper limit load DLm (No), the information processing device 100 proceeds to the process of step S176 and executes an excavation speed setting process. On the other hand, if the excavation load DL exceeds the upper limit load DLm (Yes), the information processing device 100 proceeds to the process of step S210 and determines that the obstacle cannot be cut.

[0087] In step S220, the information processing device 100 suspends the processing, and then in step S230, the information processing device 100 determines whether or not a restart request has been received. The restart request may be input by an operator operating the operation device 107 after some measure has been taken against the obstacle. If a restart request has been received (Yes), the information processing device 100 returns to the processing of step S120. On the other hand, if a restart request has not been received (No), the information processing device 100 returns to the processing of step S220 and continues the suspension of processing.

[0088] According to the modified example, it is configured to determine whether or not the obstacle can be cut based on the excavation load DL, and if it is determined that cutting is not possible, the process is suspended until some measure is taken against the obstacle. This makes it possible to prevent damage to the cutter bit 47 and the like in advance, even if the shield machine 30 encounters an unexpected obstacle.

[0089] [others] The present disclosure is not limited to the above-described embodiments, and can be modified as appropriate without departing from the spirit of the present disclosure.

[0090] For example, in the above embodiment, the AE sensor 20 is described as being installed on the rear surface of the front plate 45A of the cutter spoke 45, as shown in Figure 3, but it is also possible to install the AE sensor 20 in another part inside the cutter spoke 45 as long as the AE sensor 20 can be attached with the wave receiving surface 22 facing the face side.

[0091] As a modification of the above embodiment, the AE sensor 20 has been described as being installed on the rear surface of the bulkhead 50 as shown in FIG. 4, but it can also be installed in a part other than the bulkhead 50 as long as it is not in contact with the working face and is in a position capable of receiving AE waves propagating from the natural ground.

[0092] In the above embodiment, the information processing device 100 has been described as executing each process such as obstacle determination based on the maximum amplitude MA and energy EN of the AE signal, but it is also possible to execute the process based on only either the maximum amplitude MA or the energy EN. Also, it is also possible to use not only the maximum amplitude MA and the energy EN but also the RMS (root mean square) obtained from the AE signal. [Explanation of symbols]

[0093] 10...obstacle contact state acquisition system, 20...AE sensor, 21...case, 22...wave receiving surface, 23...connector, 30...shield tunneling machine, 31...skin plate, 32...rotating ring, 33...connecting beam, 35...driving motor, 40...cutter head, 41...rotary joint, 42...outer ring, 43...inner ring, 44...center tube, 45...cutter spoke, 45A...front plate, 46...center cutter, 47...cutter bit, 48...auxiliary cutter spoke, 49...opening, 50...partition wall, 55...chamber, 60...screw conveyor, 64...jack, 68...erector, 69...tail seal, 7 0...amplifier, 90...fixing jig, 91...angle bar, 92...holder, 93...recess, 95, 96...magnet, 100...information processing device, 101...CPU, 102...ROM, 103...RAM, 104...auxiliary storage device, 105...network IF, 107...operation device, 108...display device, 200...measurement data acquisition unit, 210...measurement data storage unit, 220...analysis processing unit, 230...analysis data storage unit, 240...obstacle determination unit, 250...type determination unit, 255...machine learning model, 260...excavation load calculation unit, 270...excavation speed setting unit, 280...excavation feasibility determination unit, S...segment, BM...backfilling material, C1, C2...cable

Claims

1. 1. An obstacle contact state acquisition system that is applied to a shield machine including a cylindrical skin plate, a cutter head provided at a front end of the skin plate, and a partition wall disposed within the skin plate facing and spaced apart from the cutter head, and that acquires a contact state of an obstacle excavated by the cutter head, an AE sensor installed at a position that is not in contact with the face of the shield machine and that can receive AE waves propagated from the natural ground; an obstacle contact state acquisition unit that acquires a contact state of the obstacle based on the AE signal acquired by the AE sensor; An obstacle contact state acquisition system comprising:

2. 2. The obstacle contact state acquisition system according to claim 1, The AE sensor is The cutter head is provided on the inside of a cutter spoke of the cutter head, or on the rear surface of the partition opposite to the cutter head. Obstacle contact status acquisition system.

3. 3. The obstacle contact state acquisition system according to claim 1, The obstacle contact state acquisition unit is An obstacle determination process is performed to determine whether or not an obstacle is present in the ground to be excavated based on the maximum amplitude and / or energy of the AE signal acquired by the AE sensor while excavating the ground. Obstacle contact status acquisition system.

4. 4. The obstacle contact state acquisition system according to claim 3, The obstacle contact state acquisition unit is When it is determined that an obstacle is present by the obstacle determination process, a type determination process is further executed to determine the type of the obstacle based on the maximum amplitude and / or energy of the AE signal of the obstacle. Obstacle contact status acquisition system.

5. 3. The obstacle contact state acquisition system according to claim 1, The obstacle contact state acquisition unit is An excavation load calculation process is executed to calculate an excavation load, which is a load when the shield machine excavates the target ground, based on the maximum amplitude and / or energy of the AE signal acquired by the AE sensor while excavating the ground. Obstacle contact status acquisition system.

6. 6. The obstacle contact state acquisition system according to claim 5, The shield machine further includes an excavation speed setting unit that reduces the excavation speed of the shield machine as the excavation load calculated by the excavation load calculation process increases. Obstacle contact status acquisition system.

7. 7. The obstacle contact state acquisition system according to claim 6, The shield machine further includes an excavation feasibility determination unit that determines whether or not the shield machine is capable of excavating the obstacle based on the excavation load calculated by the excavation load calculation process. Obstacle contact status acquisition system.

8. 1. An obstacle contact state acquisition method that is applied to a shield machine including a cylindrical skin plate, a cutter head provided at a front end of the skin plate, and a partition wall disposed within the skin plate facing and spaced apart from the cutter head, and that acquires a contact state of an obstacle excavated by the cutter head, An AE sensor is installed at a position that can receive AE waves propagated from the natural ground among a portion of the shield machine that does not contact the face, The contact state of the obstacle is acquired based on the AE signal acquired by the AE sensor.

4. A method for acquiring an obstacle contact state, comprising:

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