JP6289206B2 - Geological exploration method in tunnel excavation - Google Patents

Description

  The present invention relates to a geological exploration method in tunnel excavation, and more particularly, to a geological exploration method in tunnel excavation using a blast vibration wave caused by blasting in order to grasp in advance the geological situation in front of a face in excavation of a mountain tunnel.

Conventionally, in the excavation of a mountain tunnel, as disclosed in Patent Document 1 and Patent Document 2, in order to investigate the geological condition of the natural ground during excavation, the blast vibration generated by exploding the blast on the face is exploded. Recorded by a plurality of outside geophones installed in advance on the ground surface above the planned route outside the tunnel mine, and an underground geophone on the oscillation point side installed in the tunnel mine, and connected to the underground geophone Record synchronously. The blast vibration recorded in this recording device calculates the elastic wave propagating in the ground from the propagation velocity and amplitude attenuation, and based on this elastic wave, analyzes the geological condition above the planned route of the tunnel, There are known geological exploration methods for grasping in advance the fault crushing zone, the geological boundary, or the cracked area where rock collapse and spring water are expected to occur.
However, since an underground geophone for receiving blast vibration is installed on the ground surface in advance, the number of geophones located in front of the face decreases as the tunnel excavation progresses, There is a problem that the accuracy of grasping the geological situation of the country will deteriorate. One way to solve this problem is to increase the number of outboard geophones so that the accuracy of the geological situation does not decrease even if the face moves during tunnel excavation. Therefore, it is necessary to wire a cable for connecting the recording device provided on the side of the oscillation point in the mountain as many as the number of off-the-shelf geophones, which requires much labor. Furthermore, since the propagation distance of the blasting vibration is limited, it is difficult to predict the front of the face in an outside-surface geophone installed far from the face.

JP-A-7-259472 JP 2011-43409 A

  Therefore, in order to solve the above problems, the present invention provides a geological exploration method in tunnel excavation capable of accurately predicting the geological situation ahead of the face to be excavated in tunnel excavation.

As geological prospecting method in tunneling according to the present invention, a geophone for geophone blasting vibration caused by a geological survey method for searching the geological conditions of the working face forward in the tunnel excavation to proceed working face by repeated blasting originating broken tunnel Installed only forward of the face to be blasted on the ground surface outside the mine , receiving the blasting vibration by the geophone, and blasting ahead of the face that has advanced forward by the blast A step of moving to a ground surface at a position different from the position where the vibration is received, and a step of blasting the face after traveling and receiving the blasting vibration generated by the blasting by the shaker after the movement. Therefore, every time the face moves, the geophone moves within the range in front of the face. Geophone vibration is possible, it is possible to accurately predict the geological conditions to get more data for searching the geological conditions without increasing the number of geophones.
In addition, as another form of geological exploration method in tunnel excavation, data for investigating the geological condition of natural ground is performed because the process of receiving blasting vibration with the geophone after movement is performed every time the face after blasting is blown. It is possible to collect more and to understand the geological situation of the natural ground more accurately.
Further, as another form of geological exploration method in tunnel excavation, the geophone is moved rearward from the position where the blast vibration is received , so that the geological situation in front of the face can be examined more accurately.
As another form of geological exploration method in tunnel excavation, the geophone includes a recording device that records blasting vibrations received by the geophone, and the geophone and the recording device are accommodated in one backpack . However, since it is portable, it is easy to carry and move outside the mine.
As another form of geological prospecting method in tunneling, the geophone, since a GPS receiver for acquiring position information on the ground surface, tunneling will geophone for geophone blasting vibration in the working face forward route It can be reliably moved to a different ground level above. In addition, since the place where the geophone is grounded can be accurately identified, it is possible to accurately grasp the different geological positions in the natural ground.

It is a schematic sectional drawing which shows the mountain ground which is excavating a tunnel. It is a block diagram which shows the structure of a geological exploration apparatus. It is a flowchart which shows the process of the geological exploration method. It is a figure which shows the appearance of the analyzed elastic wave.

  FIG. 1 is a schematic cross-sectional view showing a mountain ground excavating a tunnel 10. Hereinafter, a geological exploration method in tunnel excavation according to the present invention will be described in detail with reference to the drawings. 11 indicated by a broken line in the figure is a planned excavation route of the tunnel 10. The planned excavation line 11 refers to a route planned for excavation of the tunnel, and the ground surface on the planned excavation line 11 refers to the ground surface 12 of a mountainous region located above the line. The tunnel 10 shown in FIG. 1 is under construction in a mountainous area, and is dug at intervals of several meters by repeatedly blasting the cutting edge 13 shown by a two-dot chain line in the figure. The geology in front of the face of the tunnel 10 is searched by executing one embodiment of the geological search method according to the present invention with the geological search device 1.

FIGS. 2A and 2B are block diagrams showing the configuration of the geological exploration apparatus 1. As shown in the figure, the geological exploration device 1 includes an underground observation device 2 installed in a tunnel tunnel, an underground observation device 4 installed outside a tunnel tunnel, an underground observation device 2 and an underground observation device 4. And an analysis device 5 (see FIG. 1) for analyzing the geology based on the observed blast vibration.
The underground observation device 2 includes a blasting and detonating device 21, an epicenter 22, a plurality of underground geophones 24, and an underground recording device 25.
The blasting and detonating device 21 is a device for detonating the epicenter 22 in this geological exploration, and includes a blasting device 27, a power supply line 28, and a blasting signal detector 29. The blasting device 27 is connected to the epicenter 22 via the power supply line 28, and supplies power to the seismic source 22 from the built-in power source 27A. The power supply line 28 is a conducting wire that can allow a high voltage and large current to flow. The blast signal detector 29 is a sensor that detects, without contact, that high-voltage power from the blaster 27 to each detonator 30 has flowed to the power supply line 28, and detects the blast signal with a delay of several microseconds. And output as a pulse signal to the underground recording device 25 connected to the device 29.
The epicenter 22 includes a detonator 30 and a blast (dynamite) 31. The detonator 30 is, for example, an instantaneous electric detonator (detonator that is controlled to detonate within 2 milliseconds after energization) or a DS electric detonator (decision detonator, usually at a stage delayed by 250 to 500 milliseconds). A detonator of about 10 stages is used depending on the detonator controlled by the first stage, an instantaneous electric detonator is used for the first stage, and a DS electric detonator is used for the second and subsequent stages. Note that the configuration of the detonator 30 is not limited to the above configuration, and may be any configuration.

Therefore, when a current flows from the blasting device 27 to the power supply line 28, the detonator 30 and the blasting 31 are sequentially blown up with a time delay, and blasting vibration is generated. The pulse signal output from the blast signal detector 29 to the underground recording device 25 is recorded by the internal clock built in the underground recording device 25 as the rising time of this pulse signal as the blast time, that is, the oscillation start time of the blast vibration. Is done.
The blasting is performed by a plurality of stage blasting blasts, but in this embodiment, the blasting time of the first-stage detonator 30 recorded in the underground recording device 25 is described as being processed as the oscillation time.

The underground geophone 24 is composed of a small seismometer such as a geophone (land geophone), for example, and is arranged in a plurality along the longitudinal direction of the tunnel 10 at a predetermined interval, for example, about 10 m. The underground geophone 24 is connected to the underground recording device 25 while being connected to the underground geophone 24 by a connection cable 24A.
Note that the underground geophone 24 may be arranged in advance in a borehole provided on the ground in the tunnel mine or on the side wall so as to detect the vibration state of the ground in the mine. Moreover, you may install not only in a boring hole but directly on each surface of the ceiling in a tunnel mine, a wall, and a floor.
Blast vibration data (vibration data) observed by the underground geophone 24 is converted into a digital signal and then output to the underground recording device 25.

The underground recording device 25 is a data logger including an internal clock 32, a GPS receiver 33, a power supply device 34, and a recording medium 35. The internal clock 32 is a clock that advances the time by crystal oscillation. The internal clock 32 is configured to be able to synchronize with the GPS time included in the GPS signal received by the GPS receiver 33. The GPS receiver 33 includes a GPS antenna 33a, receives GPS time included in the GPS signal received by the GPS antenna 33a, and positional information on the earth of the GPS receiver 33 based on the GPS signal received from the GPS satellite. Process.
The GPS signal is a radio wave signal including a signal (1 PPS, time information, etc.) for the purpose of time calibration emitted from a GPS (Global Positioning System) satellite.

The power supply device 34 is a storage battery composed of a secondary battery configured to be able to charge power supplied from a commercial power source of 100 V or 200 V, or a primary battery such as a dry battery, and is independent of a commercial power source of 100 V or 200 V. And is configured to be movable. The recording medium 35 is, for example, a removable storage disk.
For example, the underground recording device 25 is accommodated in an explosion-proof case or the like such that the GPS antenna 33a is exposed, and is accommodated in a bag such as a single backpack, and can be carried outside the tunnel well. Thus, by enabling the mine recording device 25 to be carried out of the tunnel mine, it is possible to maintain a state in which the time of the internal clock 32 when receiving the blasting vibration is made coincident with the time of the GPS clock.

The mine recording device 25 is taken out of the tunnel mine every time the face 13 advances, so that the internal clock 32 is synchronized with the GPS time. Each time the GPS receiver 33 receives a GPS signal, the internal clock 32 automatically synchronizes with the GPS time (reference time) included in the GPS signal, and the blast signal detected by the blast signal detector 29 described above. Is recorded as a cue at the blast start time, and the vibration receiving data inputted from the underground geophone 24 is recorded as a waveform having the time of the internal clock 32 as a time axis in the recording medium 35 containing it. Examples of the recording medium 35 include a removable memory disk and a hard disk.
The GPS receiver 33 and the GPS antenna 33a are separated from the underground recording device 25 and are provided outside the tunnel well so as to be able to receive GPS radio waves, so that the underground recording device 25 and the GPS receiver 33 can communicate with each other. You may connect by radio. Alternatively, only the GPS antenna 33a may be provided outside the tunnel shaft, and the GPS receiver 33 may be connected by wire so that a signal received by the GPS antenna 33a can be output.

  The outboard observation apparatus 4 includes an outboard exciter 41 and an outboard recording apparatus 42. The outer surface geophone 41 is composed of a small seismometer such as a geophone similar to the underground geophone 24, and receives vibration points at a plurality of locations on the ground surface 12 ahead of the face 13 of the planned excavation line 11 of the tunnel 10. Arranged as. In this embodiment, as shown in FIG. 1, each outside geophone 41 is connected by the connection cable 41A along the planned excavation line 11, and is arranged at three places. These outer surface geophones 41 are provided with an outer surface recording device 42. The off-surface geophone 41 is connected to the off-shore recording device 42 and outputs the blasting vibration that propagates to the ground surface using the epicenter 22 as the oscillation point as the receiving data received by each of the off-surface geophones 41 to the off-surface recording device 42. Note that blast vibration data (vibration data) observed by the off-surface geophone 41 is converted into a digital signal and then output to and recorded on the off-shore recording device 42.

  The outside-surface recording device 42 is a data logger provided with an internal clock (quartz timepiece) 43, and the vibration receiving data input from the outside-surface geophone 41 is used as a waveform with the time of the internal clock 43 as a time axis. Recording is performed on the recording medium 46 through a built-in recording unit. Examples of the recording medium 46 include a removable memory disk and a hard disk.

  The outside recording apparatus 42 is a data logger including an internal clock 43, a GPS receiver 44, a power supply apparatus 45, and a recording medium 46. The internal clock 43 is a clock that advances the time by crystal oscillation. The internal clock 43 is configured to be able to synchronize with the GPS time included in the GPS signal received by the GPS receiver 44. The GPS receiver 44 includes a GPS antenna 44a, receives GPS time included in the GPS signal received by the GPS antenna 44a, and positional information on the earth of the GPS receiver 44 based on the GPS signal received from the GPS satellite. For example, latitude, longitude and altitude calculation processing is performed. The position information calculated from the GPS signal is displayed on a display device (not shown). Based on this position information, the outer surface geophone 41 is on the ground surface 12 in front of the face 13 of the planned excavation line 11. It is confirmed whether it is arranged. That is, by obtaining the position of the outer surface geophone 41 in front of the face from the position information obtained from the GPS signal, the outer surface geophone 41 is reliably moved to different ground surfaces along the planned tunnel excavation route. Can do. In addition, since the place where the outside geophone 41 is grounded can be accurately identified, when analyzing the geological condition of the natural ground by the analysis device 5 described later, it is possible to accurately grasp the different positions of the geological condition in the natural ground. it can. In addition, when the outer surface geophone 41 receives the blasting vibration, the received positional information is also recorded together with the blasting vibration.

The power supply device 45 is a secondary battery configured to be able to charge power supplied from a commercial power supply of 100 V or 200 V, or a primary battery such as a dry battery, and is independent of the commercial power supply of 100 V or 200 V. And is configured to be movable.
For example, the outside recording device 42 is accommodated in a waterproof case or an explosion proof case so that the GPS antenna 44a is exposed, and a bag such as one backpack as a set of the outside observation device 4 together with the outside geophone 41 It is housed in a container such as a case as one piece of luggage and is configured to be portable outside the tunnel mine. By making the out-of-well recording device 42 movable in this way, it is easy to carry and move outside the well, and the time of the internal clock 43 when receiving the blasting vibration is made to coincide with the time of the GPS clock. Can be kept.

The analysis device 5 is constituted by a so-called personal computer having a CPU, a memory, a monitor, and the like, and excavates based on the vibration receiving data recorded by the underground recording device 25 and the underground recording device 42 and the position information received by the vibration receiving data. Analyze the geological condition of the power ground. Note that the position information received from the received vibration data may be based on surveying. As shown in FIG. 1, the analysis device 5 is installed, for example, in a field office provided outside the tunnel 10.
When vibration receiving data is input from the underground recording device 25 and the underground recording device 42, the analysis device 5 analyzes these recording data by various methods such as a refraction method, a reflection method, and a tomography analysis. Then, by analyzing this analysis result, the geology (ground) in front of the face of the tunnel 10 is predicted, and the geology of the already excavated section is evaluated.

FIG. 3 is a flowchart showing the procedure of the geological exploration method of the present invention.
Hereinafter, the procedure of the geological exploration method of the present invention will be described with reference to FIGS.
The geological exploration process includes an exploration preparation process 101, an observation device placement process 102, a blasting process 103, a vibration receiving process 104, a data recovery process 105, a data capture process 106, and an analysis process 107. The
In the exploration preparation step 101, the operation confirmation of the underground observation device 2 and the outside observation device 4, confirmation of insertion of the recording media 35 and 46, the internal clock 32 of the underground recording device 25, and the internal clock 43 of the external recording device 42 are confirmed. Set the clock. When the mine recording device 25 is in the tunnel mine, it is taken out of the tunnel mine, and the GPS antenna 33a is moved to a position where GPS radio waves can be received to synchronize the internal clock 32 with the GPS time. Further, the GPS antenna 44a of the out-of-hole recording device 42 is caused to receive GPS radio waves, and the internal clock 43 is synchronized with the GPS time. Thereby, the time of the internal clocks 32 and 43 of the underground recording apparatus 25 and the external recording apparatus 42 is synchronized.

In the observation device arrangement step 102, the detonator 30 is attached to the blast 31 provided on the face 13, the detonator 30 and the blaster 27 are connected by the power supply line 28, and the blast signal detector 29 is attached to the power supply line 28. . The blast signal detector 29 is connected to the underground recording device 25 synchronized with the GPS time. Further, in the tunnel mine, two mine geophones 24 are arranged along the longitudinal direction of the tunnel 10 at a predetermined interval, and are grounded so as to be able to receive the blasting vibration, and are connected to the mine recording device 25 via the connection cable 24A. Is done. Thus, the underground observation device 2 is disposed in the tunnel 10.
In addition, the outside observation apparatus 4 is connected to the outer surface geophone 41 on the ground surface 12 ahead of the face 13 of the planned excavation line 11 of the tunnel 10 along the planned excavation line 11 via the connection cable 41A. For example, it is grounded at three different positions. By connecting one end of the connection cable 41 </ b> A to the outside recording device 42, the arrangement of the outside observation device 4 is completed.

  In the blasting step 103, the blasting device 27 arranged in the tunnel mine by the observation device arranging step 102 is operated to supply power from the power source 27A built in the blasting device 27 to the detonator 30 through the power supply line 28, and the detonator 30 The blast 31 is blasted using as a starting material to excavate the face 13 and blast vibration is generated in the ground where the tunnel 10 is excavated. At this time, the current flowing through the power supply line 28 is detected by the blasting signal detector 29, and is output as a pulse signal to the underground recording device 25, and the earthquake occurrence time (blasting time) is recorded.

  In the vibration receiving process 104, the blast vibration generated in the natural ground is received by the two underground exciters 24 arranged in the tunnel mine and the three external exciters 41 arranged outside the tunnel mine. That is, in order to excavate the face 13 of the tunnel 10, the blast vibration with the explosion of the blast 31 provided on the face 13 propagated radially from the blast point and reached the upper surface 12 through the natural mountain. Vibration is observed by the underground geophone 41. In the underground geophone 24, the blasting vibration caused by the blasting for tunnel excavation propagates in the ground as elastic waves radiating from the blasting point, and the geology in the ground changes. The reflected wave reflected at the boundary surface is received. That is, the vibration receiving data received by the underground geophone 24 includes distance information from the blasting point to each reflecting surface.

  In the data collection step 105, the recording medium 35 and the recording medium 46 are collected from the underground recording device 25 and the outside recording device 42. Note that the recording medium 46 may be collected together with the out-of-hole recording device 42. At this time, the three outside geophones 41 may be collected together with the outside recording device 42, and only the outside recording device 42 is collected while the outside geophone 41 remains on the ground surface 12 to collect the vibration receiving data. You may make it do.

In the data fetching process 106, the vibration receiving data is taken into the analyzer 5 from the collected recording media 35 and 46.
In the analysis step 107, the vibration receiving data acquired in the data acquisition step 106 is analyzed by various methods such as a refraction method, a reflection method, and a tomography analysis. Then, by analyzing this analysis result, the geology (ground) in front of the face of the tunnel 10 is predicted.
Specifically, the analysis device 5 determines the distance between the blasting point and the installation point of the external geophone 41 from the blasting time recorded by the underground recording device 25 and the vibration receiving time of the blasting vibration recorded by the underground geophone 24. Calculate the propagation time of blast vibration at.

The analysis device 5 is based on the distance information between the blasting point inputted in advance and the measurement point of the outer geophone 41 and the propagation time until the blasting vibration is measured by each outer geophone 41. The average natural ground elastic wave velocity due to the blasting vibration between the blasting point and the underground geophone 41 is calculated. If there is a part where the geology changes in the natural ground, the average natural ground elastic wave will move up and down according to changes in the hardness of the natural ground and propagate along the path shown by the broken line in FIG. Thus, the vibration is received by the outside geophone 41.
Therefore, by calculating and analyzing the average natural ground elastic wave velocity for each outer geophone 41, it is possible to predict the natural condition, that is, the geology in the portion between the blasting point and each outer geophone 41. it can.

  Then, when excavation of the face 13 by blast 31 is performed again for excavation of the tunnel, the process returns to the exploration preparation step 101 to prepare for observation of blast vibration. That is, both the internal clock 43 of the outside recording apparatus 42 and the internal clock 32 of the underground recording apparatus 25 are always synchronized with the GPS time. In this way, the underground recording device 25 and the internal clocks 32 and 43 of the outdoor recording device 42 are always synchronized so that the time of each other can be accurately matched. The calculation accuracy of the average natural ground elastic wave velocity calculated based on the vibration receiving data of the geophone 41 and the blasting time data recorded in the underground recording device 25 can be increased, and the prediction accuracy of natural ground properties can be increased.

  In the observation device arrangement step 102, the underground observation device 2 and the outside observation device 4 are again arranged on the face 13 that has moved several meters by the previous blasting. The outer surface geophone 41 of the outer surface observation apparatus 4 is moved so as to be positioned in front of the moved face 13, and is grounded on the ground surface 12 at a position different from the previous time. The movement direction of each outer geophone 41 is not limited to the excavation direction, and as shown in FIG. 4, the movement direction may move to either the front side or the rear side as long as it is ahead of the face 13. . Thus, the prediction accuracy for predicting the geology ahead of the face 13 by moving the outside geophone 41 to a position different from the previous position and receiving the blasting vibration with the blasting 31 for tunnel excavation as an earthquake source. Can be improved with a small number of off-surface geophones 41.

  That is, every time the blast 31 for tunnel excavation is blown up, the accuracy of the geological prediction ahead of the face 13 is gradually improved by repeating the analysis preparation step 107 from the exploration preparation step 101. That is, since the blast for tunnel excavation is used as the exploration seismic source, the exploration accuracy of the tunnel geology is improved as the number of excavations of the face 13 increases.

FIG. 4 (a) is a diagram showing elastic wave paths obtained by moving the outside geophone 41 for each blasting by the method of the present invention and analyzing the vibration receiving data for three times of blasting. FIG. 4B is a diagram showing elastic wave paths obtained by fixing the outside geophone 41 by the conventional method and analyzing the vibration data for three blasts.
As shown in FIG. 4B, in the conventional method, the tunnel 10 is provided on the ground surface 12 during the construction period of the tunnel 10 on the ground surface 12 and is fixedly provided on the ground surface 12. The movements of the position b and the position c are several meters per day, and the elastic waves f′1, f ′ obtained by analyzing the blasting vibrations observed in each of the outer geophones 41 2, f′3, elastic waves g′1, g′2, g′3, elastic waves h′1, h′2, and h′3 have almost no change. That is, it can be seen that only vibration receiving data biased in front of the face 13 is obtained.
On the other hand, as shown in FIG. 4 (a), in the method of the present invention, every time the face 13 to be blasted advances to position a, position b, position c by blasting, the outer surface geophone 41 is arranged. By moving the position from positions P1, Q1, R1 to positions P2, Q2, R2, positions P3, Q3, R3 to positions different from the previously observed positions, elastic wave f1 obtained by analysis is obtained. , G1, h1, elastic waves f2, g2, h2, elastic waves f3, g3, h3 and a change in the path can be seen. 4A and 4B, according to the method of the present invention, in the geological exploration, the elastic waves f1, g1, h1, and the elastic waves that cross the ground evenly. Since the geology can be explored by the waves f2, g2, h2, and the elastic waves f3, g3, h3, it is possible to reliably improve the prediction accuracy of the geology ahead of the face 13 of the tunnel 10 to be excavated.

  In addition, according to the method of the present invention, there is no need to connect the underground recording device 25 of the underground observation device 2 and the outdoor recording device 42 of the outdoor observation device 4 to each other by wire such as a cable. 25 and the underground geophone 24, the outside recording device 42 and the underground geophone 41 can be easily arranged, and the movement thereof is facilitated, and the time from preparation required for geological exploration to analysis can be shortened. it can.

  As described above, according to the present invention, the large vibration generated by blasting (dynamite) that is always used for tunnel excavation is used for exploration ahead of the face 13 and the outside geophone 41 is used as the face. Each time the face 13 moves, the outer surface geophone 41 is moved to the ground face 12 in front of the moved face 13 to search for a geological state ahead of the face 13. By doing so, since the sampling number of the vibration receiving data for predicting the geology of the ground to be excavated from now on increases, the prediction accuracy in the geological exploration can be improved.

In the embodiment described above, a plurality of out-of-surface geophones 41 are connected to a single out-of-surface recording device 42. However, each out-of-surface geophone 41 is provided with a separate out-of-surface recording device 42 and is movable. You may comprise. In this way, by providing the outboard recording device 42 for each outboard geophone 41, it is not necessary to connect with the connection cable 41A even if the range in which the plurality of outboard geophones 41 are arranged is widened. To conduct geological exploration.
Moreover, in the said embodiment, although demonstrated as providing the multiple outside geophone 41, the one outside geophone 41 may be sufficient. That is, every time it is blasted, that is, every time the face 13 advances, the outer surface geophone 41 is moved so as to be positioned on the ground surface 12 in front of the face 13 so as to receive the blasting vibration. Even if geological exploration is performed with a set of out-of-surface observation devices 4 composed of one out-of-surface geophone 41 and one out-of-surface recording device 42, compared to when a geophone is fixedly installed as in the past. Since the geological data in front of the face 13 is obtained for each blasting number, it is possible to obtain the sampling number of the vibration receiving data that can be predicted with sufficient accuracy in the geological exploration.
Further, in the above embodiment, every time blasting is repeated, that is, every time the face 13 advances, every time the face 13 advances, the outer surface geophone 41 is moved so as to be positioned on the ground surface 12 in front of the face 13 to blast. Although it has been described that vibration is received, the outer surface geophone 41 is moved so as to be positioned on the ground surface 12 in front of the face 13 at a rate of once every two or more times such as once every two times. You may make it receive blasting vibration.

  In the above embodiment, the underground recording device 25 and the outdoor recording device 42 are determined by the GPS time received by the GPS receiver 33 provided in the underground recording device 25 and the GPS receiver 44 provided in the outdoor recording device 42. However, the present invention is not limited to the GPS receiver 33 and the GPS receiver 44, and the wireless communication that enables communication between the underground recording device 25 and the outdoor recording device 42 is possible. A device may be provided so that the internal clocks of the underground recording device 25 and the external recording device 42 are synchronized. Examples of such a wireless communication device include a wireless communication device that enables connection to a public wireless line such as an Internet line, and the time obtained through an NTP (Network Time Protocol) receiver on the Internet line. The internal clocks of the underground recording device 25 and the external recording device 42 may be synchronized with the same time.

1 Geological exploration equipment, 2 underground observation equipment, 4 outside observation equipment, 5 analysis equipment,
10 tunnels, 11 planned drilling routes, 12 ground level, 13 face,
21 blast detonator, 22 epicenter, 24 underground geophone, 25 underground recorder,
32 internal clock, 33 GPS receiver, 34 power supply, 35 recording medium,
41 Off-surface geophone, 42 Outside-surface recording device, 43 Internal clock, 44 GPS receiver,
45 power supply, 46 recording medium.

Claims (5)

A geological exploration method for exploring the geological state in front of a face in tunnel excavation where the face is advanced by repeated blasting ,
The geophone for geophone blasting vibration caused by fracture originating ground surface in the tunnel Anagai, placed only in front than the working face to be blasting subject, comprising the steps of geophone blasting vibration by the geophone,
Moving and installing the geophone on the ground surface at a position different from the position where the blasting vibration is received ahead of the face that has advanced forward by the blasting ; and
Blasting the face after progress and receiving the blasting vibration generated by the blasting by the geophone after the movement;
A geological exploration method characterized by comprising: The geological exploration method according to claim 1, wherein the step of receiving the blasting vibration by the geophone after movement is performed each time the face after progressing is blasted.
Quality exploration method. The geological exploration method according to claim 1 or 2, wherein the geophone is moved rearward from a position where the blast vibration is received . The geophone includes a recording device that records blast vibrations received by the geophone ,
The geological exploration method according to any one of claims 1 to 3, wherein the geophone and the recording device are accommodated in a single backpack and are portable .   5. The geological exploration method according to claim 1, wherein the geophone includes a GPS receiver that acquires position information on the ground surface.

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