Measuring device, measuring method, and shield machine

Abstract

To provide a measuring device, a measuring method, and a shield machine capable of grasping the condition of the ground around a tunnel.SOLUTION: A measuring device according to the present invention is installed in a tunnel excavated in the ground and measures the ground around the tunnel, and includes a plurality of geophones that measure ground vibrations from inside the tunnel caused by a vibration exciter or ground vibrations caused by tunnel excavation, and an analysis unit that analyzes and displays the ground vibrations measured by the geophones. The measuring device issues a warning when the analysis result indicates a significant change.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a measurement device, a measurement method, and a shield machine. [Background technology]

[0002] There is known a technique for constructing a tunnel without affecting the surrounding ground. Patent Document 1 proposes a shield machine for excavating natural ground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-077710 A Summary of the Invention [Problem to be solved by the invention]

[0004] In this case, the ground may be heterogeneous, and only a part of the ground around the tunnel may be soft. Also, there is a risk that the ground around the tunnel may become loose during construction. However, it has been difficult to grasp the condition of the ground around the tunnel.

[0005] In consideration of the above, an object of the present disclosure is to provide a measurement device, a measurement method, and a shield machine that are capable of grasping the condition of the ground around a tunnel. [Means for solving the problem]

[0006] A measurement device according to a first aspect of the present disclosure includes: (1) A measuring device that is installed in a tunnel excavated underground and measures the ground around the tunnel, A plurality of geophones for measuring vibrations of the ground from inside the tunnel caused by a vibration generator or vibrations of the ground caused by tunnel excavation; an analysis unit that analyzes and displays the vibration of the ground measured by the geophone; Equipped with.

[0007] A measurement device according to one embodiment of the present disclosure includes: (2) At a plurality of positions in the tunnel excavation direction, vibrations of the ground caused by the vibration exciter or tunnel excavation and an analysis of the vibrations by the analysis unit are performed, and a warning is issued when a significant change is indicated in the analysis result. The measuring device according to (1) above.

[0008] A measurement device according to one embodiment of the present disclosure includes: (3) The vibration exciter is an air knocker. A measuring device according to the above (1) or (2).

[0009] A measurement device according to one embodiment of the present disclosure includes: (4) The vibration generator and the vibration receiver are disposed inside the peripheral wall of the shield machine. A measuring device according to any one of (1) to (3) above.

[0010] A measurement device according to one embodiment of the present disclosure includes: (5) The vibration generator and the receiver are disposed on the inner peripheral wall of the skin plate of the shield machine. The measuring device according to (4) above.

[0011] A measurement device according to one embodiment of the present disclosure includes: (6) The analysis unit calculates and displays a propagation speed of the vibration of the ground. A measuring device according to any one of (1) to (5) above.

[0012] A measurement method according to a second aspect of the present disclosure includes: (7) A method for measuring the ground around a tunnel, comprising: vibrating the ground from inside the tunnel or by tunnel excavation; A step in which a plurality of geophones arranged in the tunnel measure vibrations of the ground; An analysis unit analyzes and displays the vibration of the ground measured by the recording receiver; Includes.

[0013] A shield machine according to a third aspect of the present disclosure includes: (8) A shield machine equipped with a measuring device according to any one of (1) to (6) above. Effect of the Invention

[0014] According to the present disclosure, the condition of the ground around a tunnel can be grasped. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic cross-sectional view showing a shield machine in which a measuring device according to an embodiment of the present invention is arranged, together with the ground. [Diagram 2] 1 is a diagram showing a first frequency distribution map and a variance curve created by analyzing ground vibrations measured by multiple geophones. [Diagram 3] This is a diagram showing a second frequency distribution map and dispersion curve created by analyzing ground vibrations measured by multiple geophones, and is a diagram obtained by measurement at a location where tunnel excavation has progressed from the location where Figure 2 was measured. [Figure 4] FIG. 11 is a diagram comparing the first and second dispersion curves. [Diagram 5] 2 is a flowchart for explaining a measurement method executed by the measurement device of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the same components are denoted by the same reference numerals.

[0017] 1, a measurement device 10 according to an embodiment of the present disclosure includes a geophone 12A and an analysis unit 13. The measurement device 10 may further include a vibration exciter 11.

[0018] The measurement device 10 is installed in a tunnel 1100 excavated underground (inside the ground 1000). As described below, the measurement device 10 measures the ground 1000 around the tunnel 1100. The tunnel 1100 may be located at a great depth.

[0019] At least a part of the measuring device 10 may be disposed in a sealed shield machine 100 that excavates a tunnel 1100. More specifically, the vibration exciter 11 and the receiver 12A may be fixed by screws or the like to the inside of a skin plate 110 serving as a peripheral wall of the shield machine 100. The vibration exciter 11 and the receiver 12A may be disposed on the peripheral wall inside the skin plate 110 of the shield machine 100. Note that, in the present embodiment, the measuring device 10 is described as being disposed in the shield machine 100, but the measuring device 10 may be disposed in a tunnel boring machine other than the shield machine 100, and the measuring device 10 may be disposed in the tunnel 1100 as an independent device.

[0020] The vibration exciter 11 artificially vibrates the ground 1000 from underground. The vibration exciter 11 may include an air knocker 11A, a solenoid valve 11B, a regulator 11C, an air compressor 11D, and a control unit 11E. The vibration exciter may artificially vibrate the ground 1000 from underground by something other than the air knocker.

[0021] The vibration exciter 11 may be fixed to the upper part of the shield machine 100. With this configuration, the measurement device 10 can measure the part of the ground 1000 above the shield machine 100, i.e., the ground 1000 between the tunnel 1100 and the ground surface.

[0022] The air knocker 11A may include a cylinder. When air pressure is applied to the cylinder, the cylinder may be displaced and strike the ground 1000 through the skin plate 110 of the shield machine 100.

[0023] The solenoid valve 11B may open and close by turning on and off the current. The regulator 11C may adjust the air pressure. The air compressor 11D may compress the air. When the solenoid valve 11B is open, air pressure that displaces the cylinder may be momentarily applied to the air knocker 11A.

[0024] The solenoid valve 11B, the regulator 11C, and the air compressor 11D may be connected to and controlled by a control unit 11E via wires or wirelessly.

[0025] The exciter 11 may include a sensor (e.g., a vibration sensor) that detects the excitation. When the sensor detects the excitation, the exciter 11 may transmit a signal to the seismic exploration device 12.

[0026] The measuring device 10 may measure vibrations of the ground 1000 caused by tunnel excavation, instead of measuring vibrations of the ground 1000 from inside the tunnel 1100 caused by the vibration exciter 11. In this configuration, the vibration exciter 11 does not need to be provided in the measuring device 10. Tunnel excavation may be performed by the cutter 130 of the shield machine 100.

[0027] The receiver 12A measures the vibration of the ground 1000 caused by the vibration generator 11 that vibrates the ground 1000 from inside the tunnel, or the vibration of the ground 1000 caused by tunnel excavation. The receiver 12A may measure the vibration of the ground 1000 for a certain period of time after receiving a signal from the vibration generator 11. The receiver 12A may convert the measured vibration into an electrical signal. The receiver 12A may be a velocity type receiver geophone.

[0028] A plurality of receivers 12A (e.g., six) are provided. The receivers 12A may be arranged in at least one row over the deployment length L along the axial direction of the shield machine 100. The receivers 12A may be arranged at equal intervals. The deployment length L may be designed according to the size of the space inside the skin plate 110. The deployment length L may be, for example, 10 meters. The receiver 12A may be arranged alongside the exciter 11. The distance between the exciter 11 and the receiver 12A1, which is the closest to the exciter 11 among the receivers 12A, may be 1 meter.

[0029] The receivers 12A may be part of the seismic exploration device 12. The seismic exploration device 12 may further include a data recording device 12B connected to each of the receivers 12A. The data recording device 12B may record the vibration of the ground 1000 measured by the receivers 12A. The signal may be amplified, A / D converted, and stored as digital waveform data in the analysis unit 13. The data recording device 12B may be installed in an office supervised by a site supervisor.

[0030] The analysis unit 13 analyzes and displays the vibrations of the ground 1000 measured by the multiple geophones 12A. The analysis unit 13 may be connected to the data recording device 12B by wire or wirelessly. A program may cause the analysis unit 13 to analyze and display the vibrations of the ground 1000 measured by the multiple geophones 12A. The program may be stored in the analysis unit 13. The analysis unit 13 may be a personal computer. The analysis unit 13 may be equipped with a display on which the vibrations of the ground 1000 measured by the multiple geophones 12A are displayed. The analysis unit 13 may be installed in an office supervised by a site supervisor.

[0031] An example of vibration analysis of the ground 1000 performed by the analysis unit 13 will be described below.

[0032] <Creating a Cross-Correlation CMP Record> From the obtained records, the phase difference specific to each receiving point (each receiver 12A) is extracted by the following procedure. First, the cross correlation is calculated for each combination of two waveforms between the receiver 12A closest to the excitation device 11A and each of the other receivers. The superimposed cross correlations with different receiving point intervals are arranged according to the receiving point interval. Hereinafter, the obtained records are referred to as cross correlation records.

[0033] <Conversion to frequency-phase velocity cross section> To create a dispersion curve, the cross-correlation records, which are expressed as time-distance, are converted into a frequency-phase velocity (propagation velocity) relationship diagram. First, each cross-correlation record is converted into the frequency domain by Fourier transform. Next, an arbitrary speed is given to the frequency domain waveform, and the time is shifted according to the distance of the receiving point, and stacked for the number of traces. By repeating stacking with different speeds, it is possible to determine the magnitude (frequency) of the frequency at each speed. This allows a two-dimensional frequency distribution of frequency-phase velocity to be obtained. Figure 2-3 shows the result of the conversion into a frequency-phase velocity cross section (frequency distribution diagram). In Figure 2-3, the white parts indicate areas with large stack values.

[0034] Note that Figure 3 shows a second frequency distribution map that was further created by the analysis unit 13 after the analysis unit 13 created the first frequency distribution map shown in Figure 2 and the shield machine 100 excavated one ring.

[0035] <Calculation of dispersion curve> If a wave group with a certain phase velocity actually exists, the frequency will be high in the wave group, and the location showing a large value on the frequency-phase velocity cross section will be the phase velocity (dispersion curve). In the obtained frequency-phase velocity region (first and second frequency distribution maps), the phase velocity with the maximum amplitude at each frequency is read and the dispersion curve is calculated. Specifically, dispersion curves for S-waves are shown in Figures 2 and 3. The dispersion curve is a curve that shows the relationship between frequency and propagation speed.

[0036] The S-wave velocity (of the initial model) may be calculated from the phase velocity (propagation velocity) and frequency. The S-wave velocity is directly related to the rigidity modulus of the ground 1000. Therefore, by calculating the S-wave velocity, the physical properties of the ground 1000 can be understood. The P-wave velocity may further be calculated based on the S-wave velocity.

[0037] The measuring device 10 may analyze the vibration of the ground 1000 caused by the vibration generator 11 or tunnel excavation and the vibration by the analysis unit 13 at multiple positions (for example, for each ring) in the excavation direction d of the tunnel 1100, and may issue a warning if the analysis result shows a significant change. The measuring device 10 may determine that the analysis result shows a significant change based on a comparison result between the latest dispersion curve or frequency distribution map created by the analysis unit 13 and the previous dispersion curve or frequency distribution map. Specifically, the measuring device 10 may compare (image comparison) the latest frequency distribution map itself with the previous frequency distribution map. As another example, the measuring device 10 may read the dispersion curves from the latest and previous frequency distribution maps, respectively, and compare the dispersion curves. The measuring device 10 may determine that the analysis result shows a significant change if the difference between the propagation speed of the latest dispersion curve (for example, shown by a dashed line in FIG. 3) and the propagation speed of the previous dispersion curve (for example, shown by a solid line in FIG. 2) at a specific frequency exceeds a threshold value. The threshold value may be determined based on the conditions of the ground 1000, construction management, etc. The measuring device 10 may display the latest dispersion curve and the previous dispersion curve in an overlapping manner, as shown in FIG. 4. If these dispersion curves match, it may be determined that the ground conditions at the locations corresponding to the respective dispersion curves are similar. If these dispersion curves do not match, it may be determined that the ground conditions at the locations corresponding to the respective dispersion curves are different. It may be determined that the slower the propagation speed is, the looser the ground is. If the measuring device 10 determines that there is a significant change between these dispersion curves, it may display these dispersion curves in an overlapping manner to call attention.

[0038] The measurement device 10 may display the difference between the propagation speed of the latest dispersion curve and the propagation speed of the previous dispersion curve. The warning may be issued by generating a warning sound. The analysis unit 13 may issue the warning.

[0039] Next, a measurement method executed by the measurement device 10 in this embodiment will be described with reference to the flowchart of FIG. 5. Before the measurement method is started, the excavation of the tunnel 1100 by the shield machine 100 may be stopped. This allows the measurement device 10 to measure only the vibration of the ground 1000 from inside the tunnel 1100 caused by the vibration exciter 11. The measurement method may be executed every time the shield machine 100 excavates one ring. In another embodiment, the measurement method may be executed while the shield machine 100 is excavating the tunnel 1100. In yet another embodiment, the measurement method may be executed within a segment after the segment has been constructed.

[0040] Prior to step S100, the vibration generator 11 and the receiver 12A are fixed to the inside of a skin plate 110 serving as the peripheral wall of the shield machine 100 by screws or the like.

[0041] In step S100, the vibration exciter 11 vibrates the ground 1000 from inside the tunnel 1100, or vibrates the ground 1000 by tunnel excavation 1100. Specifically, the tunnel excavation is stopped, and while the control unit 11E is causing the air compressor 11D to compress air, the solenoid valve 11B is opened to displace the cylinder of the air knocker 11A, causing the ground 1000 to be struck via the skin plate 110. The strike vibrates the ground 1000. Alternatively, the vibration exciter 11 is not used, and the tunnel 1100 is excavated by the shield machine 100 to vibrate the ground 1000.

[0042] In step S101, the geophone 12A measures the vibration of the ground 1000 caused by the vibration exciter 11 that vibrates the ground 1000 from inside the tunnel 1100, or the vibration of the ground 1000 caused by the excavation of the tunnel 1100. After receiving a signal from the vibration exciter 11, the seismic exploration device 12 may measure the vibration of the ground 1000 via the geophone 12A for a certain period of time.

[0043] The receiver 12A converts the measured vibration into an electrical signal and transmits it to the data recording device 12B. The data recording device 12B records the received electrical signal.

[0044] In step S102, the analysis unit 13 analyzes and displays the vibrations of the ground 1000 measured by the multiple geophones 12A. Here, a case will be described in which the first frequency distribution map and dispersion curve shown in Fig. 2 have already been created, and the shield machine 100 excavates one ring after the first frequency distribution map shown in Fig. 2 is created. The analysis unit 13 creates and displays the second frequency distribution map shown in Fig. 3 from the vibrations of the ground 1000 measured by the multiple geophones 12A.

[0045] The analysis unit 13 calculates a dispersion curve, which is a curve showing the relationship between frequency and propagation velocity, from the second frequency distribution diagram shown in FIG. 3. The analysis unit 13 calculates the propagation velocity of the vibration of the ground 1000, which is shown by a dotted line, from the second frequency distribution diagram shown in FIG. 3. In general, when the ground 1000 is soft, the propagation velocity of the signal is low. When the ground 1000 is hard, the propagation velocity of the signal is high. The measurement device 10 may determine that the analysis result shows a significant change when the difference between the propagation velocity of the latest dispersion curve (shown in FIG. 3) and the propagation velocity of the previous dispersion curve (shown in FIG. 2) at a specific frequency exceeds a threshold value. In this case, the measurement device 10 issues a warning. The analysis unit 13 may display the latest dispersion curve and the previous dispersion curve in an overlapping manner, as shown in FIG. 4. In general, low-frequency vibrations represent the state of the area of ​​the ground 1000 far from the receiver 12A. High frequency vibrations are indicative of the area of ​​the ground 1000 close to the receiver 12A.

[0046] The measuring device 10 of this embodiment configured as described above includes a plurality of geophones 12A that measure the vibration of the ground 1000 from inside the tunnel 1100 caused by the vibration generator 11 or the vibration of the ground 1000 caused by tunnel excavation, and an analysis unit 13 that analyzes and displays the vibration of the ground 1000 measured by the geophones 12A. With this configuration, the user of the measuring device 10 can understand the condition of the ground 1000 around the tunnel 1100, which is difficult to grasp from the ground surface, from the analysis result of the vibration of the ground 1000. Furthermore, the user of the measuring device 10 can quickly grasp the ground 1000 that has become loose during the construction of the tunnel.

[0047] Furthermore, the measuring device 10 of this embodiment analyzes vibrations of the ground 1000 caused by the vibration exciter 11 or the excavation of the tunnel 1100 and the vibrations by the analysis unit 13 at multiple positions in the excavation direction d of the tunnel 1100, and issues a warning when the analysis results show a significant change. With this configuration, the user of the measuring device 10 can more accurately recognize that the condition of the ground 1000 around the tunnel 1100 has changed (for example, the ground has become soft).

[0048] In addition, in the measuring device 10 of this embodiment, the vibration exciter 11 and the receiver 12A are disposed inside the skin plate 110 serving as the peripheral wall of the shield machine 100. With this configuration, the vibration exciter 11 and the receiver 12A can be protected from the displacement of the shield machine 100 caused by the excavation of the tunnel 1100, etc.

[0049] In addition, in the measuring device 10 of this embodiment, the vibration exciter 11 and the receiver 12A are disposed on the peripheral wall of the shield machine 100 between the cutter 130 and the erector 140 of the shield machine 100. With such a configuration, the measuring device 10 can be mounted on a shield machine of an existing design. Furthermore, since the measuring device 10 is disposed near the cutter 130 at the tip of the shield machine 100, the measuring device 10 can accurately analyze the state of the ground 1000 near the tip of the shield machine 100.

[0050] Furthermore, in the measurement device 10 of this embodiment, the analysis unit 13 calculates and displays the propagation speed of vibration in the ground 1000. With this configuration, the user of the measurement device 10 can grasp the condition of the ground 1000 around the tunnel 1100 in more detail. In general, when the ground 1000 is soft, the propagation speed of the signal is low. When the ground 1000 is hard, the propagation speed of the signal is high.

[0051] Although the present disclosure has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these modifications and corrections are included in the scope of the present disclosure. [Explanation of symbols]

[0052] 10: Measurement equipment 11: Vibrator 11A: Air knocker 11B: Solenoid valve 11C: Regulator 11D: Air compressor 11E: Control unit 12: Seismic exploration equipment 12A,12A1: Geophone 12B: Data recording device 13:Analysis Department 100: Shield machine 110: Skin plate (perimeter wall) 130: Cutter 140: Erector 1000: Ground 1100: Tunnel L: Development length d: Drilling direction

Claims

1. A measuring device that is installed in a tunnel excavated underground and measures the ground around the tunnel, A plurality of geophones for measuring vibrations of the ground from inside the tunnel caused by a vibration generator or vibrations of the ground caused by tunnel excavation; an analysis unit that analyzes and displays the vibration of the ground measured by the geophone; Equipped Measuring equipment.

2. At a plurality of positions in the tunnel excavation direction, vibrations of the ground caused by the vibration exciter or tunnel excavation and an analysis of the vibrations by the analysis unit are performed, and a warning is issued when a significant change is indicated in the analysis result. The measurement device according to claim 1 .

3. The vibration exciter is an air knocker. The measuring device according to claim 1 or 2.

4. The vibration generator and the vibration receiver are disposed inside the peripheral wall of the shield machine. The measuring device according to claim 1 or 2.

5. The vibration generator and the receiver are disposed on the inner peripheral wall of the skin plate of the shield machine. The measurement device according to claim 4.

6. The analysis unit calculates and displays a propagation speed of the vibration of the ground. The measuring device according to claim 1 or 2.

7. A method for measuring the ground around a tunnel, comprising: vibrating the ground from inside the tunnel or by tunnel excavation; A step in which a plurality of geophones arranged in the tunnel measure vibrations of the ground; An analysis unit analyzes and displays the vibration of the ground measured by the recording receiver; Measurement methods, including

8. A shield machine comprising the measuring device according to claim 1 or 2.

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