JP5319981B2 - Elastic wave exploration system - Google Patents

Description

  The present invention relates to an elastic wave exploration system that performs geological exploration using elastic waves.

  There are discontinuities such as faults and shredding zones in the natural ground when excavating underground spaces such as tunnels. If there are more discontinuities than expected and the geology of the natural ground is poor, Many collapses, large deformations, sudden springs, etc. occurred, which had a great influence on the excavation speed. Therefore, as a technique for accurately performing forward exploration in the tunnel, artificial waves are artificially applied to the ground, and the reflected waves are detected by multiple geophones and analyzed by a computer, etc. A technique for accurately detecting a discontinuous surface such as a crushing zone or the like is known (for example, Patent Document 1).

By the way, there are many uneven parts in the tunnel, and the cable of the exploration system that performs forward exploration is caught by this uneven part, and the layout of the free system component equipment cannot be done, or the search range is limited by the length of the cable It was done. In addition, the cable may be disconnected due to catching on the uneven portion. Therefore, a system component such as a vibration generating member (trigger hammer) for generating elastic waves, a receiver for detecting vibrations due to elastic waves, and an analysis computer (data logger) for analyzing vibration values are wirelessly connected, There has been proposed a technology that eliminates restrictions on the layout in which devices are installed and increases the degree of freedom of exploration (for example, Patent Document 2).
JP 2002-106290 A JP 2001-305236 A

  However, in the conventional wirelessly connected forward exploration system, it is possible to increase the degree of freedom of exploration by eliminating the restrictions on the layout in which the equipment is installed, but each of the vibration generating member, the geophone, and the analysis computer It was not taken into account that the time managed by the system gradually shifted with time. For this reason, the time between the constituent members of the forward exploration system is gradually shifted, and there is a possibility that the discontinuous surface cannot be detected accurately at the excavation site such as a tunnel.

  Accordingly, an object of the present invention is to provide an elastic wave exploration system that can detect a discontinuous surface with high accuracy while increasing the degree of freedom of exploration by eliminating the constraints on the layout by wirelessly connecting components. To do.

  The present invention relates to an elastic wave exploration system that performs geological exploration by analyzing vibration values according to propagation of artificially generated elastic waves by an analysis means, and generates vibrations by wirelessly transmitting elastic wave generation time information. Including a time transmitting means and a vibration receiving means for detecting a vibration value corresponding to the propagation of the elastic wave, the vibration receiving means receiving the generation time information wirelessly transmitted from the vibration occurrence time transmitting means, and the vibration receiving means The synchronization means for synchronizing the reference time managed by the generation time information with the generation time information, and in accordance with the propagation of the elastic wave within a predetermined time from the acquisition start time based on the reference time synchronized with the generation time A vibration value acquisition unit that acquires a vibration value and a transmission unit that wirelessly transmits the vibration value acquired by the vibration value acquisition unit to the analysis unit.

  According to the present invention, the vibration value corresponding to the propagation of the elastic wave is acquired within a predetermined time from the acquisition start time based on the reference time synchronized with the generation time of the elastic wave. Therefore, even though the vibration receiving means is wirelessly connected to the vibration occurrence time transmitting means, time synchronization is established between the reference time managed by the vibration receiving means and the elastic wave generation time based on the occurrence time information. The vibration value can be obtained with high accuracy without any time lag. Since the vibration value data is acquired with high accuracy, the analysis means can analyze using the vibration value with high accuracy. In addition, since the vibration receiving means is wirelessly connected to the vibration occurrence time transmitting means, the vibration receiving means can be arranged at a position suitable for geological analysis. As a result, it becomes possible to detect discontinuous surfaces with high accuracy.

  Furthermore, it is preferable that a plurality of vibration receiving means are provided, and the reference times managed by the vibration receiving means are synchronized with each other by the synchronization means. By synchronizing the time between the plurality of vibration receiving means, the discontinuous surface can be detected with higher accuracy.

  More preferably, the acquisition start time is a time retroactive to the elastic wave generation time based on the generation time information. In this case, by acquiring the vibration values before and after the generation time of the elastic wave, it is possible to detect the “malfunction” that occurs when generating the elastic wave artificially, and analyze the vibration value including its influence. It becomes possible to detect a discontinuous surface with higher accuracy. In addition, the “malfunction” used here is, for example, when the rock is hit manually with a vibration generating member such as a trigger hammer to generate an elastic wave artificially, the trigger hammer does not hit the rock perpendicularly, it hits the corner of the rock, This means that a predetermined elastic wave is not generated.

  The present invention further comprises analysis means for receiving a vibration value wirelessly transmitted from the transmission means and analyzing the vibration value to perform geological exploration, and the analysis means receives the vibration value from at least one vibration receiving means a plurality of times. Thus, it is preferable to stack the vibration values received a plurality of times. By such stacking processing using a plurality of vibration values, that is, vibration value superimposition processing, the magnitude of the amplitude of the vibration values can be made to stand out and the discontinuous surface can be detected with higher accuracy.

  It is preferable to further include vibration generating means for artificially generating elastic waves using the giant magnetostrictive element. When a giant magnetostrictive element is used, a certain elastic wave can be repeatedly generated, and a discontinuous surface can be detected with high accuracy.

  According to the present invention, a discontinuous surface can be detected with high accuracy while increasing the degree of freedom of exploration.

  Hereinafter, preferred embodiments of an elastic wave exploration system according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the face Ta, which is the foremost portion of the pit T, moves forward with the excavation work of the tunnel. When the face Ta moves forward, if there is a discontinuous surface S such as a fault, shatter zone, formation boundary surface, cavity, etc. in the natural ground M, the face Ta collapses or sudden springs occur, and the tunnel This may greatly affect the excavation speed and construction cost. Therefore, it is important to accurately predict and evaluate geological information such as the discontinuous surface S in front of the face Ta when excavating the tunnel. Therefore, it is necessary to search for the discontinuous surface S prior to excavation. The elastic wave exploration system 1 is a system for exploring such a discontinuous surface S in front of the face Ta.

  As shown in FIGS. 1 and 2, the elastic wave exploration system 1 is a member for artificially generating an elastic wave EW toward the front of the face Ta, and is a trigger signal indicating the generation time of the elastic wave EW ( Trigger hammer 3 for generating the generation time information) and a plurality of geophones (vibration means) 5 for detecting a vibration value by the reflected wave RW reflected by the discontinuous surface S and returned by the elastic wave EW generated by the trigger hammer 3. Wireless transmitter / receiver (vibration occurrence time transmitting means) that can bidirectionally communicate with a plurality of geophones 5 and that receives a trigger signal from the trigger hammer 3 and wirelessly transmits the trigger signal to the geophone 5 ) 7 and an analysis computer (analysis that detects the position, inclination, scale, relative hardness, etc. of the discontinuous surface S by computer analysis of vibration values and the like due to the reflected wave RW received by the plurality of geophones 5 hand ) It is provided with a 9, a.

  The trigger hammer 3 is a vibration generating member for artificially generating elastic waves EW composed of P waves and S waves in all directions including the front face of the face Ta by hitting a predetermined rock in the mine shaft T in the vertical direction. The signal line L is wired to the wireless transceiver 7 and the analysis computer 9. The trigger hammer 3 is arranged on the striking surface side and wirelessly transmits and receives a hit detection unit 3a that detects a hit with a built-in piezoelectric element, and a detection voltage detected by the hit detection unit 3a as a trigger signal indicating the generation time of the elastic wave EW. And a transmitter 3b for transmitting to the machine 7 and the analysis computer 9.

  Such a trigger hammer 3 wirelessly transmits to the plurality of geophones 5 a trigger signal for hitting detected by the hitting detection unit 3 a via the wireless transceiver 7. Simultaneously with this wireless transmission, the trigger hammer 3 transmits a trigger signal to the analysis computer 9 via the signal line L. Further, the trigger hammer 3 generates an elastic wave EW (also referred to as a direct wave) directly propagating through the pit wall of the mine T in addition to the elastic wave EW forward in the excavation direction by hitting the rock. Is directly transmitted to the geophone 5 through the pit wall. When the trigger hammer 3 is hit against a rock, the trigger hammer 3 may not be perpendicular to the rock surface, and a “malfunction” may occur at the corner of the rock.

  The geophone 5 is a vibration receiving means that detects vibration due to the reflected wave RW and vibration due to the direct wave, acquires vibration value data indicating the amplitude of vibration within a predetermined time, and wirelessly transmits the vibration value data. The geophone 5 receives a vibration detection unit (vibration value acquisition means) 5 a that detects and acquires a vibration value by a reflected wave RW or a direct wave, and a trigger signal that is wirelessly transmitted from the trigger hammer 3 via the wireless transceiver 7. And a transmission / reception unit (reception unit, transmission unit) 5b for wirelessly transmitting vibration value data acquired by the vibration detection unit 5a to the analysis computer 9, and a trigger received by the transmission / reception unit 5b for the reference time t1 managed by the geophone 5 A built-in timer (synchronizing means) 5c that synchronizes with the generation time of the elastic wave EW by the signal and a drive power supply 5d for driving the geophone 5 are provided.

  In the present embodiment, ten of the above-described geophones 5 are prepared, and each of the geophones 5 is disposed on the pit wall of the pit T at a predetermined interval. The geophone 5 is set so as to always detect a vibration value after being placed on the pit wall and temporarily store the detected vibration value in a temporary storage memory (not shown). When receiving the trigger signal from the trigger hammer 3, the geophone 5 acquires the vibration value stored in the temporary storage memory as vibration value data for transmission and wirelessly transmits it to the analysis computer 9. Thereby, compared with the case where vibration value data is always transmitted wirelessly, power saving and long life of the drive power source 5d made of, for example, a battery can be achieved.

  Here, the vibration value data acquired by the geophone 5 will be described with reference to FIG. As shown in FIG. 3, the vibration values detected by the ten geophones 5 are represented by A1 to A10, respectively. When the geophone 5 receives a trigger signal from the trigger hammer 3, time synchronization is established between the reference times t1 managed by the built-in timer 5c of each geophone 5, and the reference time t1 and the elastic wave EW are generated in each geophone 5. The time is synchronized, and the reference time t1 of each geophone 5 is synchronized with each other, and the acquisition of vibration value data is started from the vibration value acquisition start time t0 (0 ms).

  The acquisition of vibration value data is started from a time (acquisition start time t0) that goes back a predetermined time from a reference time t1 synchronized with the time of occurrence of the elastic wave. This is for accurately detecting the discontinuous surface S by performing an analysis including the influence of “malfunction” that occurs when the trigger hammer 3 is struck. That is, when a “malfunction” occurs at the time of impact and the elastic wave EW is insufficient, an accurate vibration value cannot be detected as it is. Therefore, by comparing the vibration value data before and after the occurrence time of the elastic wave EW, it is detected whether or not “malfunction” has occurred, and when the “malfunction” is detected, the analysis computer 9 appropriately sets the vibration value data. Correct the value. The acquisition of the vibration value data going back in time in this way is executed using the vibration value data stored in the temporary storage memory described above.

  When the vibration value data acquisition is started at the acquisition start time t0, the geophone 5 first detects the vibration caused by the direct wave propagated to the geophone 5 between the times t2 and t3, and the vibration value data. Subsequently, the vibration value by the reflected wave RW is detected after time t3 to acquire vibration value data, and the vibration value data is acquired within a predetermined time until time t4 (128 ms). Then, each geophone 5 collectively transmits the vibration value data acquired during a predetermined time of 128 ms to the analysis computer 9.

  The wireless transmitter / receiver 7 is a wireless transmitter / receiver capable of bidirectionally communicating with a plurality of geophones 5, and wirelessly transmits a trigger signal from the trigger hammer 3 to the transceiver unit 5 b of the geophone 5. 5 is received and transmitted to the analysis computer 9. The wireless transceiver 7 is connected to the trigger hammer 3 and the analysis computer 9 via a signal line L.

  The analysis computer 9 is a detecting means for analyzing the vibration value data by the reflected wave RW and the direct wave and detecting the position and inclination of the discontinuous surface S. The analysis computer 9 includes a CPU, a RAM, a ROM, and the like, and includes a detection unit 9a that detects the position of the discontinuous surface S by analyzing vibration value data, a monitor 9b that displays a detection result by the detection unit 9a, and an analysis PC device including an external storage device 9c storing a computer program and the like, and a built-in timer 9d that synchronizes the reference time managed by the analysis computer 9 with the generation time of the elastic wave EW by the input trigger signal is there.

  The analysis computer 9 analyzes vibration value data (see FIG. 3) from the plurality of geophones 5, detects the position and inclination of the discontinuous surface S, and displays the results on the monitor 9b. It is. When the analysis computer 9 receives the trigger signal from the trigger hammer 3, the analysis computer 9 synchronizes the time by the built-in timer 9 d based on the trigger signal, receives vibration value data from the plurality of geophones 5, and receives a plurality of vibration value data, The position and inclination of the discontinuous surface S are detected by computer analysis of the arrangement position of the geophone 5 and the hit position by the trigger hammer 3. Then, the analysis computer 9 outputs and displays the detected position and inclination of the discontinuous surface S on the monitor 9b. In the computer analysis, the vibration value data is received from the same geophone 5 a plurality of times, and the amplitude value in the vibration value data is obtained by stacking the vibration value data, that is, by superimposing the vibration values. May be made to stand out to improve the analysis accuracy.

  Next, a method for analyzing the discontinuous surface S using the above-described elastic wave exploration system 1 will be described. First, ten geophones 5 are respectively arranged and fixed at a predetermined interval on the pit wall of the tunnel mine T. When placing the geophone 5 on the pit wall, the geophone 5 is not connected to the trigger hammer 3 or the analysis computer 9 by wire, so that the geophone 5 can be easily placed and fixed, and the layout can be freely set. be able to. Thereafter, the ten geophones 5 are turned on.

  Subsequently, the elastic wave EW is artificially generated by hitting a predetermined rock in the mine T in the vertical direction by the trigger hammer 3. At this time, a trigger signal is simultaneously wirelessly transmitted from the trigger hammer 3 to the geophone 5 via the radio transceiver 7, and the generation time of the elastic wave EW, each reference time t 1 managed by each geophone 5, and the analysis computer 9 All of the managed reference times are synchronized, and collection of vibration value data is started from the acquisition start time t0 based on the synchronized reference time t1 (see FIG. 3). In the present embodiment, since the analysis including the influence of the “malfunction” by the trigger hammer 3 is performed, the acquisition start time t0 is a time that goes back a predetermined time from the generation time of the elastic wave EW.

  By hitting the rock with the trigger hammer 3, first, a direct wave propagates directly through the well wall and is transmitted to the geophone 5, and the geophone 5 that starts acquiring vibration value data acquires vibration value data based on the direct wave. Subsequently, the elastic wave EW caused by the rock hitting the trigger hammer 3 travels through the natural ground M and is reflected by the discontinuous surface S to generate the reflected wave RW. The plurality of geophones 5 that have acquired or ended acquisition of vibration value data by direct waves detect and acquire vibration value data by this reflected wave RW (t2 to t3), and a time at which a predetermined time has elapsed from the acquisition start time Acquisition of vibration value data is terminated at t4 (128 ms). After the acquisition of the vibration value data, each of the plurality of geophones 5 wirelessly transmits the vibration value data at a predetermined time to the analysis computer 9 via the wireless transceiver 7.

  The analysis computer 9 that has received the vibration value data from each of the plurality of geophones 5 receives the vibration value data acquired by each geophone 5, the arrangement position of each geophone 5 and the trigger hammer stored in advance in RAM, ROM, and the like. The position and inclination of the discontinuous surface S are detected by the detection unit 9a based on information such as the hit position 3. When the analysis computer 9 detects the occurrence of “malfunction” by comparing the vibration value data before and after the generation time of the elastic wave EW in the received vibration value data, the analysis computer 9 corrects the vibration value data to an appropriate value. . And the analysis computer 9 outputs the position and inclination of the discontinuous surface S detected by the detection part 9a to the monitor 9b. Thereby, the geological information such as the discontinuous surface S in front of the face Ta is accurately predicted and evaluated. Note that the geophone 5 may continuously acquire and transmit vibration value data, and the analysis computer 9 may perform analysis for geological exploration using a part of the vibration value data.

  According to the elastic wave exploration system 1 described above, the reflected wave due to the elastic wave EW within a predetermined time from the acquisition start time t0 to t4 based on the reference time t1 synchronized with the generation time of the elastic wave EW by the built-in timer 5c. The vibration value by RW or direct wave is acquired. For this reason, although the geophone 5 is wirelessly connected to the trigger hammer 3 and the radio transceiver 7, time synchronization is established between the reference time managed by the geophone 5 and the generation time of the elastic wave by the trigger hammer 3. Therefore, vibration value data can be obtained with high accuracy without any deviation between the two times. Since the vibration value data is acquired with high accuracy, the analysis computer 9 can perform geological analysis using high-precision vibration values. Moreover, since the geophone 5 is wirelessly connected to the trigger hammer 3 and the radio transceiver 7, the geophone 5 can be arranged at a position preferable for geological analysis. As a result, the discontinuous surface S can be detected with high accuracy.

  Further, the reference time t1 managed by each of the plurality of geophones 5 is synchronized with each other by each built-in timer 5c. Since the reference time t1 is synchronized among the plurality of geophones 5, each vibration value data can be compared with each other by the analysis computer 9, so that the discontinuous surface S can be detected with higher accuracy.

  In addition, this invention is not limited to the above-mentioned embodiment. For example, in the above-described embodiment, the trigger hammer 3 and the analysis computer 9 are wiredly connected via the signal line L. However, the trigger hammer 3 and the analysis computer 9 each have wireless means so that they are wirelessly connected to each other. It may be. In this case, the generation time of the elastic wave EW by the trigger hammer 3 and the reference time managed by the built-in timer of the analysis computer 9 are the same method as the time synchronization of the reference time t1 between the trigger hammer 3 and the geophone 5 described above. Are preferably synchronized.

  In the above embodiment, the trigger hammer 3 which is a vibration generating member is used. However, instead of the trigger hammer 3, blasting may be used as a vibration generating member. The elastic wave EW may be generated artificially using vibration generating means such as machine vibration, breaker vibration, or electromagnetically controlled oscillator. For example, according to the vibration generating means using the giant magnetostrictive element as the vibration generating source, even when the elastic wave EW is generated a plurality of times, the uniform elastic wave EW can be generated. According to the vibration generating means, it is possible to strongly generate an S wave having a higher resolution than the P wave, thereby further increasing the accuracy of the analysis of the discontinuous surface S.

  Further, in the above embodiment, the vibration caused by the direct wave and the reflected wave RW from the discontinuous surface S is detected by the geophone 5 to detect the position and inclination of the discontinuous surface S. The present invention may be used in an elastic wave exploration system in which only the geophone 5 is detected and the geology near the pit wall is investigated.

It is a schematic side view which shows the state which has detected the discontinuous surface ahead of a face by the elastic wave search system which concerns on embodiment of this invention. It is a block diagram of the elastic wave exploration system concerning this embodiment. It is a figure which shows the vibration value data acquired with a geophone.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Elastic wave exploration system, 3 ... Trigger hammer, 3a ... Hitting detection part, 3b ... Transmission part, 5 ... Vibration receiver (vibration means), 5a ... Vibration detection part (vibration value acquisition means), 5b ... Transmission / reception part (transmission means) , Receiving means), 5c ... built-in timer (synchronizing means), 5d ... drive power supply, 7 ... wireless transceiver (vibration occurrence time sending means), 9 ... analysis computer, 9a ... detection unit, 9b ... monitor, 9c ... external storage Device: 9d: Built-in timer, L: Signal line, M: Ground mountain, S: Discontinuous surface, T ... Tunnel, Ta ... Face, EW ... Elastic wave, RW ... Reflected wave, t0 ... Acquisition start time, t1 ... Reference Times of Day.

Claims (4)

An elastic wave exploration system that performs geological exploration by analyzing vibration values according to the propagation of artificially generated elastic waves with an analysis means,
Vibration generation time transmitting means for wirelessly transmitting the generation time information of the elastic wave;
Anda geophone for detecting a vibration value corresponding to the propagation of the acoustic wave,
The geophone,
Receiving means for receiving the occurrence time information wirelessly transmitted from the vibration occurrence time transmitting means;
Synchronization means for synchronizing a reference time managed by the geophone with the generation time of the elastic wave according to the generation time information;
A storage memory for storing continuously detected vibration values;
Vibration for acquiring a vibration value corresponding to the propagation of the elastic wave within a predetermined time set based on the propagation of the direct wave and the reflected wave from the acquisition start time based on the reference time synchronized with the occurrence time A value acquisition means;
Transmitting means for wirelessly transmitting the vibration value acquired by the vibration value acquiring means to the analyzing means;
With
The acquisition start time, Ri time der retroactive from the time of occurrence of the acoustic wave by the generating time information,
When the receiving means receives the occurrence time information, the vibration value acquisition means acquires a part of vibration values stored in the storage memory as a vibration value according to propagation of the elastic wave, and transmits the transmission value. means, acoustic wave exploration system collectively the obtained vibration value, characterized that you wirelessly transmitted to the analysis means. Comprising a plurality of said geophone,
Elastic wave exploration system according to claim 1, characterized in that it is synchronized with each other by said reference time said synchronizing means managed by the geophones respectively. An analysis means for receiving the vibration value wirelessly transmitted from the transmission means and analyzing the vibration value to perform a geological exploration;
3. The elastic wave exploration system according to claim 1, wherein the analysis unit receives the vibration value a plurality of times from at least one of the geophones and stacks the vibration value received a plurality of times. 4. . The elastic wave exploration system according to any one of claims 1 to 3, further comprising vibration generation means for artificially generating the elastic wave using a giant magnetostrictive element.

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