JP7405369B2 - Floating rock determination method and floating rock determination support system - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act (1) Presentation at the research meeting Publication date: December 1, 2020 Text type: Poster Publication location: International Society of Rock Mechanics 2019 Special Meeting - 5th Young Researchers The 5th ISRM Young Scholars' Symposium on Rock Mechanics and International Symposium on Rock Engineering ng for Innovative Future) Okinawa Convention Center (4-Mashiki, Ginowan City, Okinawa Prefecture) 3-1) (2) Publication in publications Publication date: January 20, 2020 Publication: Proceedings of the 40th Annual Conference of the Laser Society of Japan Publisher: Laser Society of Japan (General Incorporated Association) (3 ) Publication in publications Publication date: March 1, 2020 Publication: Proceedings of the 2020 National Conference of the Institute of Electrical Engineers of Japan Publisher: Institute of Electrical Engineers of Japan, General Incorporated Association

The present invention relates to a floating rock determination method and a floating rock determination support system for determining the presence or absence of floating rocks in a tunnel face.

Traditionally, various management methods have been used to ensure the safety of the construction site in mountain tunnel construction, which involves repeatedly excavating the ground using blasting or mechanical excavation, and then lining the ceiling and side walls with concrete. It is being considered.

For example, Patent Document 1 discloses a tunnel face safety monitoring system that constantly monitors a series of processes related to the NATM construction method. Specifically, the entire face of the tunnel is used as one measurement surface, and each of a plurality of observation points set on this measurement surface is continuously measured at a predetermined period using a vibration visualization radar.

During operations where vibrations are applied to the face (such as during blast drilling or shearing), signs of the face collapsing are detected based on changes in the dominant frequency and cumulative amplitude calculated from continuous measurement results. do. On the other hand, during work that does not generate vibrations on the face (such as spraying of charges or concrete), signs of face collapse are detected based on the displacement amount and displacement speed of the face surface calculated from continuous measurement results. .

JP2019-219333A

As described above, in Patent Document 1, the entire face surface is used as one measurement surface, and this face surface is monitored using a vibration visualization radar. Then, the displacement of this measurement surface is extracted in real time from the measurement results obtained through monitoring, and signs of face collapse are detected. However, it is complicated to continuously monitor the displacement of the entire face throughout the construction period of face excavation, from the blast hole to the concrete spraying.

The present invention was made in view of such problems, and its main purpose is to quickly and accurately determine the presence or absence of floating rocks at the face of a tunnel without using large-scale equipment. An object of the present invention is to provide a floating rock determination method and a floating rock determination support system.

In order to achieve such an object, the floating rock determination method of the present invention vibrates a tunnel face at which an observation point for observing the presence or absence of floating rocks is set, detects vibrations at the observation point, and converts vibration information into actual vibrations. An information acquisition step of acquiring information, and a floating rock determination step of determining the presence or absence of floating rocks at the observation point based on the actual vibration information acquired in the information acquisition step and preset reference vibration information. , the reference vibration information is set based on vibration information acquired from a healthy part of the face, and the floating rock determination step is performed by determining the time from the start of vibration until convergence between the actual vibration information and the reference vibration information. , dominant frequency, and amplitude are different from each other, it is determined that there is a floating stone.

Further, the floating rock determination method of the present invention is characterized in that, in the information acquisition step, the face is struck and vibrated by a knocking operation to knock off the floating rocks.

Further, the floating rock determination method of the present invention is characterized in that information regarding the presence or absence of floating rocks determined in the floating rock determination step is outputted to the output device in a superimposed manner on the image data of the face.

Furthermore, the floating rock determination method of the present invention is characterized in that information regarding the presence or absence of floating rocks determined in the floating rock determination step is directly output to the face.

According to the floating rock determination method of the present invention, vibration information based on a sound part of the face is used as reference vibration information, and three evaluation indicators are compared between this reference vibration information and actual vibration information acquired at an observation point. to determine whether there are floating stones. This makes it possible to quickly and accurately determine the presence or absence of floating stones by acquiring actual vibration information of the face when necessary, without having to constantly observe the face.

In addition, by carrying out the work to determine if there are floating rocks in parallel, additional work to determine whether there are floating rocks can be carried out at observation points that have been determined to have floating rocks, and the work can be done in parallel. This prevents work such as hitting the entire face with a hydraulic breaker to prevent oversight. This makes it possible to significantly shorten the construction time related to construction work.

Furthermore, the information regarding the presence or absence of floating rocks is directly synchronized with the face by outputting it to an output device such as a display or by using a projection mapping method, superimposed on the image data of the face. Alternatively, it is also possible to use a laser pointer to illuminate points on the face where floating rocks are determined to be present. This allows on-site workers to more accurately recognize the position of floating rocks on the face, making it possible to improve the workability of the rock removal work as well as work accuracy.

The floating stone determination support system of the present invention is a floating rock determination system used in the floating rock determination method of the present invention, which includes a vibration measuring device that detects vibrations generated in a tunnel face due to excitation and acquires vibration information as actual vibration information; A determination support device that supports floating stone determination based on three evaluation indicators of time from start to convergence, predominant frequency, and amplitude acquired from actual vibration information, and the determination support device a reference information setting means for setting reference vibration information based on vibration information acquired from a face; and an information comparison means for obtaining comparison information between the actual vibration information and the reference vibration information regarding the three evaluation indicators; The present invention is characterized by comprising an image display means for displaying an image of information regarding the presence or absence of floating rocks determined based on the comparison information.

Further, in the floating stone determination support system of the present invention, the determination support device detects the presence or absence of a deviation between the actual vibration information and the reference vibration information for the three evaluation indicators based on the comparison information, The present invention is characterized by comprising a floating stone determining means that determines that there is a floating stone when at least one of them is separated.

According to the floating rock determination support system of the present invention, the determination support device calculates the three points of convergence time, dominant frequency, and amplitude between the reference vibration information based on the sound part of the face and the actual vibration information acquired at the observation point. Comparison information related to evaluation indicators is output. As a result, field workers can use this comparative information as support information to determine the presence or absence of floating rocks, making it possible to perform floating rock determination with high accuracy without being affected by the level of skill of field workers. can.

Furthermore, since the determination support device is equipped with an image display means, the results of the floating rock determination can be provided as visual information to a display mounted on a mobile terminal carried by a field worker or a device used for work in the field. This makes it possible to prevent floating stones from being overlooked, which is likely to occur during work, and to prevent serious accidents such as falling skin.

Furthermore, by providing the determination support device with a floating rock determination means, it is also possible to automatically determine the presence or absence of floating rocks based on comparison information regarding three evaluation indicators: convergence time, dominant frequency, and amplitude. Thereby, it becomes possible to carry out the floating rock determination of the face with higher accuracy and quickly.

According to the present invention, by acquiring actual vibration information of the tunnel face when necessary without the need for constant observation of the tunnel face, the presence or absence of floating rocks on the tunnel face can be determined quickly and with high accuracy without using large-scale equipment. It becomes possible to judge.

FIG. 2 is a diagram showing how a floating rock determination work is performed in parallel with a rock removal work in an embodiment of the present invention. 1 is a diagram showing details of a floating stone determination support system according to an embodiment of the present invention. It is a figure which shows the procedure when carrying out floating rock determination work in parallel with the rock removal work in embodiment of this invention. FIG. 2 is a diagram (part 1) showing a state of floating stone determination work output on a display in an embodiment of the present invention. FIG. 3 is a diagram (part 2) showing the state of the floating rock determination work output on the display in the embodiment of the present invention. It is a figure which shows the floating stone determination screen output to the display in embodiment of this invention. FIG. 3 is a diagram (part 3) showing the state of floating stone determination work output on the display in the embodiment of the present invention. It is a figure showing the experimental result of floating stone detection in an embodiment of the present invention (in the case of no floating stones). It is a figure showing the experimental result of floating stone detection in an embodiment of the present invention (in the case where floating stones are present).

The present invention utilizes the fact that when vibration occurs in a tunnel face, the vibration characteristics are different between a healthy part of the face (a face surface without floating stones) and floating stones, and supports the determination of the presence or absence of floating stones in the tunnel face. It is something. In this embodiment, a floating rock determination method and a floating rock determination support system will be explained in detail below with reference to FIGS. 1 to 9, taking as an example a case where floating stones are determined while carrying out work. .

Note that Kosoku work refers to the work of excavating the ground by blasting or mechanical excavation, and then knocking off floating rocks (rocks that have separated from the ground) that are present at the face where the ground is exposed.

≪Floating rock determination support system≫
As shown in FIG. 1, after the excavation work is completed, the excavation work is performed at the face F by striking with the hydraulic breaker B, and the floating stone determination support system 100 is used to make use of the vibrations generated by the striking. F floating stone determination is being carried out.

As shown in FIGS. 1 and 2, the floating stone determination support system 100 includes a vibration measuring device 10 that acquires vibration information in an evaluation target area E1 set in a face F, and a vibration isolation table that protects the vibration measuring device 10. 20, and a determination support device 30 that supports floating stone determination based on vibration information.

As shown in FIG. 2, the vibration measuring device 10 includes a laser vibrometer 11, a vibrometer controller 12 that controls the laser vibrometer 11, a scanner 13, and a scanner controller 14 that controls the scanner 13. Further, in this embodiment, an oscilloscope 15 that can display the vibration waveform acquired by the laser vibrometer 11 is provided, but the oscilloscope 15 does not necessarily need to be provided.

The laser vibrometer 11 irradiates a measurement laser L onto a face F, which is an object to be measured, and detects changes in the frequency of the laser light reflected by the face F, and detects vibrations such as the speed and displacement of the object to be measured. It uses a so-called laser Doppler vibrometer to acquire information. Regarding its performance, it is preferable to use the vibration meter controller 12 to measure displacements of about 10 to 20 μm and vibration speeds of about 2 KHz or less when determining floating stones on the face F.

The scanner 13 is used for pinpoint irradiation of a desired point with the measurement laser L, and employs a so-called galvano scanner. The galvano scanner includes a laser beam reflecting mirror 131, which can be controlled by the scanner controller 14 to rotate to a desired angle. Thereby, the measurement laser L of the laser vibrometer 11 can be accurately scanned within the evaluation target area E1 set on the face F via the scanner 13.

As shown in FIG. 1, the vibration isolating table 20 includes a vibration isolating table 21 placed inside the tunnel, and a soundproof box 22 in which at least the laser vibrometer 11 and the scanner 13 are housed. Thereby, the laser vibrometer 11 and the scanner 13 are able to suppress the influence of vibrations and sound vibrations transmitted from the ground while the hydraulic breaker B is in operation, and can acquire vibration information of the face F with high accuracy.

Note that the distance D between the installation position of the vibration isolation table 20 and the face F is approximately 20 to 30 m, as shown in FIG. 2, in order to secure a work area near the face F. However, the distance D may be adjusted as appropriate depending on the working conditions at the construction site, the measurable distance of the laser vibrometer 11, and the like.

The determination support device 30 is connected wirelessly or wired to the vibration measuring device 10 so as to be able to send and receive data, and as shown in FIG. It includes a device 33, a file device 34, and a main memory 35.

Examples of the input device 31 include a keyboard, scanner, touch panel, etc., and examples of the output device 32 include a display, a printer, and the like. Further, the central processing unit 33 is a computer having a CPU, a GPU, a ROM, a RAM, a hardware interface, and the like.

The file device 34 is a storage device such as a semiconductor memory or a hard disk drive. Although the details will be described later, for example, an observation point file 341, an evaluation target area file 342, a reference information file 343, a vibration information file 344, an evaluation index file 345, a comparison information file 346, a floating stone determination result file 347, etc. are stored. .

In addition to the above-mentioned files, the file device 34 appropriately stores files recording information necessary for tunnel construction, such as position information of the face F, geological information of the ground, or image data of the face surface. Good.

The main memory 35 temporarily stores programs and data that can be executed by the central processing unit 33. Although details will be described later, for example, evaluation area setting means 351, reference information setting means 352, evaluation index extraction means 353, information comparison means 354, floating stone determination means 355, and image display means 356 are provided.

The above-mentioned determination support device 30 receives the vibration information acquired by the laser vibrometer 11 via the vibration meter controller 12, and outputs support information to assist field workers in determining floating stones based on this vibration information. . Furthermore, it is possible to output to the output device 32 information regarding the presence or absence of floating rocks determined by the field worker based on this support information and information regarding the presence or absence of floating rocks automatically determined by the new determination device 30. There is.

Note that the information regarding the presence or absence of floating rocks is output not only by the output device 32 of the determination support device 30 described above, but also by the display of a laptop computer or tablet terminal carried by a field worker, or the display provided in the hydraulic breaker B. For example, the image may be output by superimposing it on the image data of the face.

Furthermore, a projection mapping method may be adopted in which information regarding the presence or absence of floating stones is directly synchronized with the face F, or may be output to a wearable terminal such as smart glasses. In this way, on-site workers can more accurately recognize the position of the floating rock on the face F, making it possible to improve the workability of the rock removal work and to improve the work accuracy.

≪≪Floating rock determination method≫≫
Regarding the floating stone determination method using the above-mentioned floating rock determination support system 100, the procedure will be explained along with the details of the floating rock determination support system 100 according to the flowchart of FIG.

≪Pre-processing: steps 1-2≫
In carrying out floating rock determination on the face F, first, as shown in Fig. 4(a), the entire surface of the face F is divided into sections, and an observation point P is set to irradiate the measuring laser L to the center of the box formed by the division. Set. The position information of these observation points P is recorded in an observation point file 341 and stored in the file device 34. Further, the interval between the observation points P may be appropriately set according to the ground condition and the size of the detected floating rock, and in this embodiment, the interval is set to 20 cm.

In parallel with the setting of such an observation point P, and before carrying out the rock removal work using the hydraulic breaker B, the field worker visually checks the entire face F and roughly confirms the location of the floating rock.

≪Floating stone determination: steps 3 to 8≫
<Evaluation target area setting process: step 3>
As shown in FIG. 4(b), the striking position T of the hydraulic breaker B is determined in order to carry out the work of removing the floating stones that have been visually confirmed. When positional information regarding this striking position T is input to the judgment support device 30, the central processing unit 33 receives a command from the evaluation area setting means 351 stored in the main memory 35, and selects an unevaluated area near the striking position T. As shown in FIG. 4(c), an evaluation target area E1 is set where floating rock determination is performed.

The evaluation target area E1 may be automatically set by the determination support device 30 as described above, or may be appropriately selected by a field worker. Specifically, the image data of the face F and the position information of the observation point P recorded in the observation point file 341 are linked to the output device 32 of the determination support device 30, as shown in FIG. Output the image. In this way, the field worker can set the evaluation target area E1 while referring to this output image, and can input its position information via the input device 31.

The positional information regarding the evaluation target area E1 set by any of the above means is recorded in the evaluation target area file 342 and stored in the file device 34. Further, information regarding the evaluation target area E1 and the observation point P to which the measurement laser L is irradiated may be output as an image to the output device 32.

Regarding the setting range of the evaluation target area E1, in Fig. 4(c), the number of observation points P is set to include 4 divided boxes vertically and 4 horizontally, for a total of 16 points, but the number is as follows. It is not limited to. Any setting may be used as long as the measurement laser L is within a range where vibration information can be acquired without being blocked by construction machines working in the work area near the face F.

Moreover, the setting shape of the evaluation target area E1 does not necessarily have to be a rectangular shape, and for example, the measurement laser L may be set in an arc shape centered on the hitting position T. In this way, since the distance from the striking position T can be made constant at multiple observation points P, the amplitude of the three evaluation indicators (convergence time, dominant frequency, amplitude) obtained from the vibration information of each observation point P can be Highly accurate data can be obtained. The details of the three evaluation indicators will be given to the floating stone determination process (steps 6 to 8) described later.

Furthermore, the evaluation target area E1 is not limited to one location with respect to the striking position T of the hydraulic breaker B, but may be set at a plurality of locations, such as on the left and right, above and below the striking position T.

<Information acquisition process: step 4>
Once the evaluation target area E1 has been set, work to remove the floating rocks that have been visually confirmed begins, and the vibration measuring device 10 collects actual vibration information at each of the 16 observation points P included in the evaluation target area E1. Obtain as R.

Acquisition of actual vibration information R by the vibration measuring device 10 begins with the laser vibrometer 11 controlled by the vibrometer controller 12 irradiating the laser beam reflecting mirror 131 of the scanner 13 with a measurement laser L. The scanner 13 moves the irradiation position of the measurement laser L within the evaluation target area E1 by rotating the laser light reflecting mirror 131 while being controlled by the scanner controller 14, as shown in FIG. 5(a).

When the measurement laser L is irradiated onto the observation point P, the laser vibrometer 11 detects changes in the frequency of the laser light reflected at the observation point P, and collects vibration information such as the vibration speed and displacement of the observation point P. It is acquired as actual vibration information R and stored in the vibration meter controller 12. Note that the hydraulic breaker B strikes the face F about five times per second, and the laser vibration meter 11 acquires actual vibration information R from one observation point P for each strike.

In order to obtain the actual vibration information R in this way, the scanner controller 14 of the vibration measuring device 10 uses the observation point file 341 and the evaluation target area file 342 stored in the file device 34 of the determination support device 30. It is preferable to obtain positional information regarding P and the evaluation mode area E1.

In this way, the scanner controller 14 refers to this information, sets the irradiation order of the 16 observation points P as shown in FIG. 5(a), and irradiates the measurement laser L in this irradiation order. Thus, the rotation speed and rotation angle of the laser beam reflecting mirror 131 are controlled. Note that the position information regarding the observation point P and the evaluation mode area E1 may be directly input to the scanner controller 14 without using the determination support device 30.

The actual vibration information R acquired by the vibration measurement device 10 is input from the vibration meter controller 12 to the determination support device 30 via the input device 31. Then, the central processing unit 33 receives commands from the evaluation index extraction means 353 stored in the main memory 35, records these in a vibration information file 344, and stores it in the file device 34. Note that the actual vibration information R is linked to the position information of the observation position P.

In addition, the central processing unit 33 receives a command from the evaluation index extracting means 353, organizes the information related to the three evaluation indexes from the actual vibration information R, records it in the evaluation index file 345, and stores it in the file device 34. .

When the evaluation index file 345 is stored, as shown in FIG. Output to 32. Similarly, information related to the three evaluation indicators is output to the output device 32 from the data of the reference vibration information S (details will be described later) recorded in the reference information file 343. The comparison information between the actual vibration information R and the reference vibration information S is not only output to the output device 32 but also recorded in a comparison information file 346 and stored in the file device 34.

<Setting reference vibration information S: step 5>
The reference vibration information S to be compared with the actual vibration information R is vibration information representing a healthy portion of the face F, and is set in advance before making the floating rock determination. The setting method may be any method, but for example, a vibration waveform is acquired from information regarding a sound part of the face F in past tunnel construction and input into the reference information file 343.

Alternatively, the reference vibration information S may be set by performing a test measurement in advance to set the reference vibration information S for the face F that is the object of the floating stone determination. The setting method in this case is as follows.

First, an area that has been confirmed to contain healthy parts and floating rocks by visual inspection by a field worker is set as a test area. Note that as long as it is confirmed that the area includes at least a healthy part, that area may be set as the test area. Next, in the procedure of <Information Acquisition Step: Step 4> described above, a plurality of pieces of vibration information of a healthy part and a plurality of pieces of vibration information of floating stones in the test area are obtained using the vibration measuring device 10. When the vibration information of the test area is input to the determination support device 30 via the input device 31, the central processing unit 33 receives a command from the reference information setting means 352 stored in the main memory 35.

The central processing unit 33 receives the command from the reference information setting means 352, and uses an appropriate statistical method to determine the optimum reference vibration information as information regarding the sound part of the face F, based on the vibration information of the sound part and the vibration information of the floating stones. S is set, recorded in the reference information file 343, and stored in the file device 34.

<Floating stone determination process: step 6>
As mentioned above, three evaluation indicators (convergence time, dominant frequency, amplitude) are compared between the standard vibration information S set in advance and the actual vibration information R at the observation point P, and the actual vibration information R and the standard vibration information S are compared. If there is a discrepancy in at least one evaluation index between the two, the observation point P from which the actual vibration information R was acquired is determined to be a floating rock.

≪≪Floating rock detection experiment≫≫
These three evaluation indicators used for determining floating rocks are based on the knowledge obtained by the inventors through intensive studies that a floating rock that is excited vibrates in a unique mode determined by its shape and the state of contact with its surroundings. The indicators were selected based on the following. Note that among the three evaluation indicators of convergence time, dominant frequency, and amplitude, convergence time refers to the time from the start of vibration until convergence.

Figures 8 and 9 show the results of a demonstration test to detect floating stones. In the test, the surface of the ground where floating stones were present was vibrated by hitting it with a hydraulic breaker B, and the vibration information of the healthy part of the ground and the floating stones was obtained using the vibration measuring device 10. The positions of healthy parts of the ground and floating stones were confirmed in advance by performing a hammering test.

FIGS. 8(a) and 8(b) show vibration information obtained from a healthy part of the ground (without floating stones), and FIGS. 9(a) and 9(b) show vibration information obtained from floating stones. In both FIGS. 8 and 9, the top row is a graph plotted as a function of time and amplitude, and the bottom row is a scalogram plotting the absolute value of the continuous wavelet transform of the signal as a function of time and frequency.

Comparing FIG. 8 and FIG. 9, it can be seen that floating stones have characteristics such as a lower dominant frequency, a larger amplitude, and a longer convergence time than a healthy part. In other words, the reference vibration information S representative of the sound part of the face F is set in advance, and the reference vibration information S and the actual vibration information R are compared using three evaluation indicators, and the actual vibration information R is obtained through observation. It can be said that the presence or absence of floating rocks at point P can be detected.

For this reason, the determination support device 30 acquires comparison information between the actual vibration information R acquired at the observation point P and the reference vibration information S representative of the sound part of the face F for the three evaluation indicators, and determines the floating stone determination. We decided to support the The determination regarding the presence or absence of floating rocks using this comparison information may be performed by a field worker or by the determination support device 30.

<Identification of floating rocks by workers; step 6-1>
When the on-site worker determines floating stones, comparison information is output to the output device 32, as shown in FIG.

Information related to the three evaluation indicators is a graph plotted as a function of time and amplitude, and a scalogram plotted as a function of time and frequency for each of the reference vibration information S and actual vibration information R, as in the test results described above. is displayed. However, the output method may be any means as long as the actual vibration information R and the reference vibration information S can be visually compared.

Thereby, the field worker relatively compares the actual vibration information R with the reference vibration information S regarding the three evaluation indicators, and confirms whether there is any deviation. If at least one of the three evaluation indicators deviates, it can be determined that the observation point P is a floating rock or that there is a floating rock at the observation point P. At this time, for example, an input screen for the determination result is displayed together with the comparison information on a touch panel that has both the input device 31 and the output device 32.

Then, the field worker can input the determination result regarding the presence or absence of floating rocks into the determination support device 30 via the touch panel while confirming the comparison information. Information regarding the presence or absence of floating stones inputted into the determination support device 30 is recorded in a floating rock determination result file 347 and stored in the file device 34.

<Automatic judgment by judgment support device: step 6-2>
When the determination support device 30 automatically determines the presence or absence of floating rocks at the observation point P, when setting the reference vibration information S, it also determines the allowable range that can be determined as a healthy area for each of the three evaluation indicators. It is a good idea to set this.

Then, the central processing unit 33 receives a command from the floating stone determination means 355 stored in the main memory 35, and refers to the comparison information between the reference vibration information S and the actual vibration information R recorded in the comparison information file 346. If the actual vibration information R falls within the allowable range of the reference vibration information S for each of the three evaluation indicators, it is determined that there is no deviation, and the observation point P is determined to be a healthy area.

On the other hand, if at least one of the three evaluation indicators does not fall within the allowable range, it is determined that there is a deviation, and it is determined that the observation point P is a floating rock or that there is a floating rock at the observation point P. Then, this determination result is recorded in a floating rock determination result file 347 in association with the position information of the observation point P, and is stored in the file device 34.

≪Image display≫
When the floating stone determination result is recorded in the floating stone determination result file 347, the central processing unit 33 receives a command from the image display means 356 stored in the main memory 35 and outputs the determination result to the output device 32. Although any output method may be used, an example of displaying the image information on the display is shown in FIG. 5(b).

In Fig. 5(b), when setting the observation point P to which the measurement laser L is irradiated, the box that divides the entire surface of the face F is colored, thereby displaying the floating rock determination result as a visible image. There is. These floating rock determination results are not only superimposed on the image data of the face F and output to the output device 32, but also displayed on tablet terminals carried by site workers or on the display mounted on the hydraulic breaker B. That's good. In this way, it is possible to confirm the area on the face where floating stone determination has been performed, making it possible to prevent oversights in the determination work and to significantly improve work efficiency.

<Additional process: steps 7-8>
As shown in FIGS. 5(c) and 5(d), the task of determining floating rocks while performing the above-mentioned rock removal work is repeated for each location of floating rocks that has been visually confirmed in advance (step 2). In this way, it is confirmed whether floating rock determination has been performed for all observation points P set on the entire surface of the face F.

≪Floating rock determination process in unevaluated area: steps 9 to 11≫
Among the plurality of observation points P set on the face F, if there is an observation point P for which floating rock determination has not been performed, as shown in Fig. 7(a), there are unevaluated observation points P including unevaluated observation points P. An area E2 is set, and its position information is input to the determination support device 30 via the input device 31. Then, the central processing unit 33 receives the command from the evaluation area setting means 351 stored in the main memory 35, records this information in the evaluation target area file 342, and stores it in the file device 34.

Next, as shown in FIG. 7(b), an excitation point T2 for vibrating the face F is set near this unevaluated area E2. After this, while hitting the excitation point T2 with the hydraulic breaker B, the presence or absence of floating stones is determined for each observation point P in the unevaluated area E2 in the same manner as in the above floating rock determination process (steps 6 to 8). I do.

Information regarding the presence or absence of floating stones, which is the determination result, is recorded in a floating stone determination result file 347 and stored in the file device 34. Further, the central processing unit 33 receives a command from the image display means 356 stored in the main memory 35, and outputs the determination result to the output device 32, as shown in FIG. 7(c). Additionally, it may be displayed on a tablet terminal carried by a field worker or on a display mounted on the hydraulic breaker B.

≪Post-processing process: steps 12 to 13≫
After determining the presence or absence of floating rocks at each of all observation points P set on the entire face F, a hydraulic breaker B is used to carry out breakage work at observation points P where it has been determined that there are floating stones. According to the above procedure, the Kosok work is completed for all the observation points P determined to be floating rocks.

As mentioned above, the floating rock determination method uses vibration information based on the sound part of the face F as the standard vibration information S, and between this standard vibration information S and the actual vibration information R acquired at the observation point P, three evaluation indexes ( After comparing the convergence time, predominant frequency and amplitude), the presence or absence of floating stones is determined. As a result, by acquiring actual vibration information of the face F when necessary without constantly observing the face F, it becomes possible to quickly and accurately determine the presence or absence of floating stones.

In addition, it is only necessary to carry out additional work at the observation point P where it was determined that there are floating rocks, and the entire face F is hit with the hydraulic breaker B in order to prevent oversight, as was done in the past. You can prevent tasks such as This makes it possible to significantly shorten the construction time related to construction work.

The floating stone determination support system 100 uses the determination support device 30 to determine three types of vibration information, namely, convergence time, dominant frequency, and amplitude, between the reference vibration information S based on the sound part of the face F and the actual vibration information R acquired at the observation point P. Outputs comparison information related to evaluation indicators. As a result, field workers can use this comparative information as support information to determine the presence or absence of floating rocks, making it possible to perform floating rock determination with high accuracy without being affected by the level of skill of field workers. can.

Furthermore, since the determination support device 30 is equipped with the image display means 356, it is possible to provide the results of floating rock determination as visual information to a display installed in a mobile terminal carried by a site worker or a device used for work in the field. can. This makes it possible to prevent floating stones from being overlooked, which is likely to occur during work, and to prevent serious accidents such as falling skin.

Furthermore, by providing the floating rock determination means 355 in the determination support device 30, it is also possible to automatically determine the presence or absence of floating rocks based on comparison information regarding three evaluation indicators: convergence time, dominant frequency, and amplitude. Thereby, it becomes possible to carry out the floating rock determination of the face with higher accuracy and quickly.

Note that the floating rock determination method and floating rock determination support system of the present invention are not limited to the above-described embodiments, and various changes can be made without departing from the spirit of the present invention.

For example, in this embodiment, the floating rock determination was performed in parallel with the rock removal work, but it may also be performed using the vibration of the face that occurs during such tunnel construction work, or other methods may be used for the purpose of floating rock determination. Vibrations may be generated in the face F by hitting the face F with the means described above.

In this case, the means for vibrating the face F is not limited to the hydraulic breaker B; for example, the face F may be irradiated with a shock wave excitation laser to cause the face F to vibrate.

Further, in this embodiment, the laser vibrometer 11 and the scanner 13 are used as the vibration measuring device 10, but any means may be used as long as it is a means for acquiring vibration information at the observation point P set on the face F. . For example, when a vibration visualization radar is used, vibrations at a plurality of observation points P set on the face F can be acquired at once if there are no obstacles between the vibration visualization radar and the face F.

Further, in this embodiment, an example is given in which information regarding the presence or absence of floating rocks is displayed as an image, but any method may be used as long as the site worker can visually confirm the position of floating rocks.For example, if it is determined that there are floating rocks, The observation point P may be illuminated using a laser pointer on the face F.

Further, in the present embodiment, the evaluation target area E1 is set for the face F, and vibration information is acquired for the observation point P included in the evaluation target area E1, but the present invention is not necessarily limited to this. Depending on the ground conditions, the area of the face F, etc., the evaluation target area E1 may not be provided, and vibration information may be continuously acquired from all observation points P set on the face F.

100 Floating stone determination support system 10 Vibration measurement device 11 Laser vibrometer 12 Vibration meter controller 13 Scanner 131 Laser light reflector 14 Scanner controller 15 Oscilloscope 20 Vibration isolation table 21 Earthquake isolation table 22 Soundproof box 30 Determination support device 31 Input device 32 Output Device 33 Central processing unit 34 File device 341 Observation point file 342 Evaluation target area file 343 Standard information file 344 Vibration information file 345 Evaluation index file 346 Comparison information file 347 Floating stone determination result file 35 Main memory 351 Evaluation area setting means 352 Standard information Setting means 353 Evaluation index extraction means 354 Information comparison means 355 Floating stone determination means 356 Image display means

F Face B Hydraulic breaker P Observation point T1 Impact position T2 Excitation point E1 Evaluation target area E2 Unevaluated area E2
R Actual vibration information R
L Measurement laser

Claims (6)

an information acquisition step of vibrating a tunnel face at which an observation point for observing the presence or absence of floating rocks is set, while detecting vibration at the observation point and obtaining vibration information as actual vibration information;
a floating rock determination step of determining the presence or absence of floating rocks at the observation point based on the actual vibration information acquired in the information acquisition step and preset reference vibration information;
The reference vibration information is set based on vibration information acquired from a healthy part of the face,
In the floating stone determination step, at least one of the three evaluation indicators of time from start of vibration to convergence, dominant frequency, and amplitude deviates between the actual vibration information and the reference vibration information. A method for determining a floating rock, comprising determining that there is a floating rock at the observation point. The floating stone determination method according to claim 1,
A floating stone determination method characterized in that, in the information acquisition step, the face is struck and vibrated by a knocking operation to knock off floating stones. The floating stone determination method according to claim 1 or 2,
A method for determining a floating rock, characterized in that information regarding the presence or absence of a floating rock determined in the floating rock determining step is superimposed on image data of a face and output to an output device. The floating stone determination method according to claim 1 or 2,
A floating rock determination method characterized in that information regarding the presence or absence of floating rocks determined in the floating rock determination step is output to a face. A floating stone determination system used in the floating stone determination method according to any one of claims 1 to 4,
A vibration measuring device that detects vibrations generated in a tunnel face due to excitation and obtains vibration information as actual vibration information;
a determination support device that supports floating rock determination based on three evaluation indicators, namely, time from start to convergence of vibration, predominant frequency, and amplitude, obtained from the actual vibration information;
The determination support device is
a reference information setting means for setting reference vibration information based on vibration information acquired from a healthy face;
Information comparison means for acquiring comparison information between the actual vibration information and the reference vibration information regarding the three evaluation indicators;
A floating rock determination support system comprising: an image display unit that displays information regarding the presence or absence of floating rocks determined based on the comparison information. In the floating stone determination support system according to claim 5,
The determination support device
Based on the comparison information, detecting the presence or absence of a deviation between the actual vibration information and the reference vibration information for the three evaluation indicators, and determining that there is a floating stone when there is a deviation in at least one of the evaluation indicators. A floating rock determination system characterized by comprising a means.

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