JP2018194472A - In-hole probe, and in-hole ground layer detection device and method using the same - Google Patents

Abstract

To measure an elastic wave speed and an attenuation factor accurately at low cost regardless of the presence of water.SOLUTION: A transmission probe 20S includes a cylindrical container 22 having openings on side faces, an expandable tube 24 installed in the cylindrical container 22, a transmission sensor 26S inserted inside the tube 24, an injection and discharge pipe 30 for injecting and discharging a liquid 28 into and from the tube 24, and a signal line 32 connecting the transmission sensor 26S with the outside. The transmission probe is inserted into a hole (12) of ground (10) together with similarly configured reception probes 20R1, 20R2 including reception sensors 26R1, 26R2, and the liquid 28 inside the transmission probe 20S and reception probes 20R1, 20R2 is pressurized to cause the tube 24 to be expanded and abut against a hole wall. Thereafter, a signal is detected, which is received at the reception sensors 26R1, 26R2 when a high-frequency continuous wave is generated by the transmission sensor 26S, and thereby an elastic wave speed and an attenuation factor propagating in the hole wall are detected.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an in-hole probe, and an in-hole logging apparatus and method using the same, and particularly suitable for use in evaluating the soundness of a rock in front of a tunnel. The present invention relates to an in-hole probe capable of accurately measuring a low-cost and a ground borehole logging apparatus and method using the same.

  Forward exploration of mountain tunnels, such as the New Australian Tunnel Method (NATM), is important to prevent tunnel collapse. Recently, the ground collapsed due to the collapse of the tunnel in Hakata, causing great damage. In order to prevent the collapse of the tunnel, it is necessary to conduct an appropriate forward survey and select an appropriate construction method. To this end, it is necessary to investigate the elastic wave velocity and the presence or absence of cracks, but it is difficult to accurately grasp the current forward exploration method.

  For example, a face called tunnel navigation that measures acceleration of a drilling rod attached to the tip of a drill jumbo when performing horizontal drilling, acquires drilling energy, and measures elastic wave velocity using a conversion formula There is a forward exploration method (see Patent Documents 1 and 2), and there is an advantage that it does not take time and effort.

  There is also a method called core boring, in which core boring is performed while collecting cores (rock cores) horizontally, and physical tests of the acquired cores are performed to obtain elastic wave velocity and crack information. There is an advantage that it can be acquired.

  There is also a method for obtaining the velocity by performing horizontal boring called PS logging and inserting a P-wave and S-wave velocity measuring device.

JP-A-11-182171 JP 2004-132804 A

  However, in tunnel navigation, since parameters are estimated and calculation is performed, not only errors and variations are large, but also fine cracks cannot be seen. Moreover, since core boring is expensive and requires an extra work period, it is difficult to implement in accordance with the on-site process in which the downtime that can be used for measurement is, for example, about 8 hours once a week. Furthermore, PS logging has a large external device, so it requires not only additional boring, but it cannot be used without water, cannot be used if the hole wall is uneven, and the accuracy of the obtained speed is poor. Have the following problems.

  The present invention has been made to solve the above-mentioned conventional problems, and accurately measures the elastic wave velocity at a low cost, and utilizes the fact that if there is a crack, the amplitude of the elastic wave is attenuated and the attenuation factor is increased. Then, it is an object to be able to grasp information such as the presence or absence of cracks by measuring the attenuation rate of elastic waves.

  The present invention includes a cylindrical container that can be inserted into a hole and provided with an opening on a side surface, an inflatable tube that is installed in the cylindrical container, a sensor that is inserted into the tube, The above-mentioned problem is solved by an in-hole probe comprising an injection / discharge tube for injecting and discharging a liquid to and a signal line connecting the sensor to the outside.

  The present invention also provides a cylindrical container which can be inserted into a hole and has an opening on a side surface, an inflatable tube installed in the cylindrical container, a transmission sensor inserted into the tube, and the inside of the tube An injection / discharge tube for injecting and discharging liquid, a transmission probe having a signal line for connecting the transmission sensor to the outside, a cylindrical container having an opening on a side surface, which can be inserted into the hole, and the cylindrical shape An inflatable tube installed in a container, a receiving sensor inserted into the tube, a pouring tube for injecting and discharging liquid into the tube, and a receiving probe having a signal line connecting the receiving sensor to the outside Pressurizing means for pressurizing the liquid in the transmitting probe and the receiving probe, expanding the tubes of the transmitting probe and the receiving probe to contact the hole wall, and generating a high-frequency continuous wave in the transmitting sensor. Means for detecting a signal received by the receiving sensor, and means for detecting a velocity and an attenuation rate of an elastic wave propagating through the hole wall from the received signal. The above-mentioned problem is similarly solved by this borehole logging device.

  Here, a connecting rod having a predetermined interval between the transmission probe and the reception probe can be further provided.

  Further, the length of the connecting rod can be made variable.

  Further, the continuous wave can be a pseudo random wave.

  Further, the frequency of the continuous wave can be made variable.

  According to the present invention, the borehole logging device of the ground is inserted into the hole of the ground, the liquid of the transmitting probe and the receiving probe is pressurized to bring the tube into contact with the hole wall, and the high frequency continuous wave is applied to the transmitting sensor. The above-mentioned problem is similarly solved by detecting the signal received by the receiving sensor at the time of occurrence and detecting the velocity and attenuation rate of the elastic wave propagating through the hole wall.

  Here, the transmitting probe and the receiving probe connected by the connecting rod can be inserted into the same hole.

  Moreover, it can measure by changing the length of the connecting rod.

  Further, the transmitting probe and the receiving probe can be inserted into different holes.

  Further, the continuous wave can be a pseudo random wave.

  Moreover, it can measure by changing the frequency of the continuous wave.

  According to the present invention, it is possible to accurately measure the elastic wave velocity and the attenuation rate at low cost with very little error and variation. It can be measured with or without water. The on-site work time is about 1 to 2 hours, the analysis time is about 1 to 2 hours, and it can be measured within a machine downtime (for example, 8 hours). Furthermore, not only the speed but also the crack information can be grasped from the attenuation rate. It is also possible to measure crack information not only in the vicinity of the hole wall of a boring hole that has been loosened by boring hole drilling, but also from the elastic wave velocity and damping rate of a healthy part away from the hole wall not affected by drilling. it can.

Sectional drawing which shows the basic composition of embodiment of the probe in a hole which concerns on this invention Cross-sectional view showing the same measurement Cross-sectional view showing a state where it is inserted into a bedrock that also has unevenness Sectional drawing which shows the state which is measuring in the same hole using 1st Embodiment of this invention Similarly, a cross-sectional view showing a state where a place away from the hole wall is being measured Cross-sectional view showing a state where it is also inserted in the back of the borehole Diagram showing an example of experimental results according to the present invention Diagram showing another example A diagram showing still another example A diagram showing still another example A diagram showing still another example Sectional drawing which shows the state which is measuring using two holes by 2nd Embodiment of this invention

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by the content described in the following embodiment and an Example. In addition, the constituent elements in the embodiments and examples described below include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in the so-called equivalent range. Furthermore, the constituent elements disclosed in the embodiments and examples described below may be appropriately combined or may be appropriately selected and used.

  A basic configuration of the in-hole probe used in the embodiment of the present invention is shown in FIG. The in-hole probe 20 includes, for example, a metal cylindrical container 22 having an opening provided on a side surface (upper and lower surfaces in the figure) that can be inserted into a boring hole 12 dug in the bedrock 10 and the cylindrical shape. An expandable, for example, rubber tube (hereinafter referred to as a rubber tube) 24 installed in the container 22, a sensor 26 made of, for example, a piezoelectric element inserted into the rubber tube 24, and the rubber tube 24 In addition, an injection / discharge pipe 30 for injecting and discharging a liquid (for example, water) 28 and a signal line 32 connected to the sensor 26 are provided.

  In the figure, 34 is a pump for pressurizing the liquid 28 from the outside, and 36 is a computer that performs necessary arithmetic processing according to the signal of the sensor 26 input / output via the signal line 32.

  The inner diameter A of the boring hole 12 may be 4 cm, the outer diameter B of the cylindrical container 22 may be 2 cm, and the length C may be 15 cm, for example.

  When such an in-hole probe 20 is inserted into, for example, a boring hole 12 provided in the rock 10, first, as shown in FIG. 1, the rubber tube 24 contracts without injecting liquid into the rubber tube 24. Insert in the state.

  When reaching a predetermined measurement position in the boring hole 12, the liquid 28 is poured from the pouring / discharging pipe 30, the rubber tube 24 is expanded, and is crimped to the wall surface of the boring hole 12, as shown in FIG. The liquid 28 in the rubber tube 24 maintains a predetermined pressure, for example, 0.1 Mpa.

  Since the rubber tube 24 is deformed according to the shape of the hole wall, the rubber tube 24 is in close contact with the hole wall even if the hole wall is uneven as shown in FIG. Therefore, sound waves can be transmitted / received with or without liquid in the borehole 12.

  Hereinafter, a first embodiment will be described in which two or more in-hole probes are used for measurement, one for transmission and the rest for reception. In the first embodiment, as shown in FIG. 4, a transmission probe 20S having a piezoelectric element as a transmission sensor 26S inserted therein and two reception probes 20R1 and 20R2 having piezoelectric elements as reception sensors 26R1 and 26R2 inserted therein, for example, These are connected to each other by connecting rods 40A and 40B having variable lengths that can be expanded and contracted (hereinafter referred to as telescopic rods) and inserted into the borehole 12, and the velocity of the elastic wave propagating through the hole wall is measured. Is. The distance between the sensors can be, for example, 25 cm, 50 cm, 100 cm, and the like.

  By changing the frequency of the signal to be transmitted and the distance between the probes in the hole, the depth of propagation of the sound wave can be changed as shown in FIG. Thereby, two types of elastic wave velocities and attenuation rates of the loose region 10A near the hole wall and the healthy region 10B separated from the hole wall can be measured. For example, in the case of the loose region 10A, the frequency is 5 kHz to 10 kHz and the distance between the sensors is 1.00 m to 2.00 m, and in the case of the healthy region 10B, the frequency is 30 kHz to 60 kHz and the distance between the sensors is 0.30 m to 0.50 m. it can.

  In practice, as shown in FIG. 6, the length of the borehole 12 to be investigated can be adjusted using, for example, a vinyl chloride pipe or rod 42, the force of a person 44 or the hydraulic pressure of a machine such as a drill jumbo. For example, the probe 20S + 20R1 + 20R2 having a total length D of about 1 m is pushed into a predetermined position by force and installed. By changing the length of the rod 42, for example, an investigation from E = 1 m to 200 m ahead can be performed.

  Note that the number of reception probes is not limited to two, and may be one or three or more.

  According to this embodiment, an appropriate single frequency (for example, 5 kHz, 10 kHz, 50 kHz, 100 kHz, etc.) can be transmitted by controlling the frequency and oscillation amplitude using a continuous wave such as a high-frequency pseudorandom wave. Two types of information, speed and attenuation rate, and information on the vicinity of the hole wall and the part away from the hole wall can be obtained with high accuracy.

  The horizontal drilling has a problem that the hole wall is uneven, but has a mechanism for transmitting and receiving from the inside of the rubber tube 24 filled with the liquid 28, and the rubber tube 24 responds to the unevenness of the hole wall. Therefore, measurement is possible even if the hole wall is uneven. The material of the tube 24 is not limited to rubber, and may be another material having similar stretchability.

  Further, since the above mechanism is provided, it is not necessary to fill the hole with water. Furthermore, the amplitude can be measured accurately, and the attenuation due to cracks can also be measured. Furthermore, since the measuring device is small, existing horizontal drilling can be used. In addition, by changing the frequency and the sensor distance, it is possible to acquire both the vicinity of the hole wall and the speed at a place away from the hole wall.

  Moreover, since the piezoelectric element is used for the sensor, the transmission sensor and the reception sensor can be shared. The sensor is not limited to a piezoelectric element.

  In addition, since the telescopic rod is used as the connecting rod, the distance between the sensors can be easily changed. It is also possible to use a rod that cannot be expanded and contracted.

  The material of the rod is not limited to vinyl chloride.

  The inventor changes the target member, the state of the contact surface, the distance between sensors and the oscillation frequency, and shows the results of experiments.

  FIG. 7 shows the results of measurement with a distance between sensors of 0.60 m and an oscillation frequency of 39 kHz with the contact surface being dry with respect to the concrete slab. The elastic wave velocity of the P wave is 2.7 km / s (sound pressure 55 dB), and the elastic wave velocity of the surface wave is 1.7 km / s (sound pressure 76 dB).

  Further, FIG. 8 shows the results of an experiment conducted on the same concrete floor slab with the contact surface wet, with a sensor distance of 0.55 m and an oscillation frequency of 39 kHz. It can be seen that an elastic wave velocity of P wave of 2.7 km / s (sound pressure 70 dB) can be measured. Although the surface acoustic wave velocity has scaled over, the surface acoustic wave velocity can also be measured as in FIG.

  FIG. 9 shows the results of measurement at a distance between sensors of 0.70 m and an oscillation frequency of 39 kHz with the contact surface wet with respect to the concrete floor slab. It can be seen that both the elastic wave velocity of P wave 2.7 km / s (sound pressure 57 dB) and the elastic wave velocity of surface wave 1.7 km / s (sound pressure 85 dB) can be measured.

  FIG. 10 shows the results of measurement with a distance between sensors of 0.50 m and an oscillation frequency of 52 kHz, with the contact surface wet in concrete pavement. The elastic wave velocity of the P wave is 3.5 km / s (sound pressure 59 dB). The surface acoustic wave velocity has been scaled over, but it can be measured.

  FIG. 11 shows the results of measurement at a distance between sensors of 0.30 m and an oscillation frequency of 52 kHz, with the contact surface wet asphalt pavement. Both the P wave elastic wave velocity of 1.8 km / s (sound pressure 49 dB) and the surface wave elastic wave velocity of 1.1 km / s (sound pressure 59 dB) can be measured.

  Next, a second embodiment of the present invention using two holes is shown in FIG.

  In the present embodiment, the transmitting probe 20S is inserted with a rod 42S into a predetermined position of one hole (lower hole in the figure) 12A, and many (in the figure with rods 42R) in the other hole (upper hole in the figure) 12B. Eight) receiving probes 20R1 to 20R8 are inserted to perform two-dimensional measurement between the bore holes 12A and 12B.

  In any of the above embodiments, the present invention is used for tunnel forward exploration, but the scope of application of the present invention is not limited to this, and a simple investigation of the ground using a vertical hole is also possible. is there.

DESCRIPTION OF SYMBOLS 10 ... Bedrock 10A ... Loose area | region 10B ... Healthy area | region 12, 12A, 12B ... Boring hole 20 ... In-hole probe 20S ... Transmission probe 20R1-20R8 ... Reception probe 22 ... Cylindrical container 24 ... Rubber tube 26 ... Sensor 26S ... Transmission sensor 26R1, 26R2 ... Reception sensor 28 ... Liquid 30 ... Pumping discharge pipe 32 ... Signal line 34 ... Pump 36 ... Computer 40A, 40B ... Extension (connection) rod 42, 42R, 42S ... Bar 44 ... Human

Claims (12)

A cylindrical container having an opening on a side surface, which can be inserted into the hole;
An inflatable tube installed in the cylindrical container;
A sensor inserted into the tube;
An injection / discharge tube for injecting and discharging liquid into the tube;
A signal line for connecting the sensor to the outside;
An in-hole probe comprising: A cylindrical container that can be inserted into the hole and has an opening on the side surface, an inflatable tube installed in the cylindrical container, a transmission sensor that is inserted into the tube, and injecting and discharging liquid into the tube An injection / discharge pipe for transmitting, a transmission probe having a signal line for connecting the transmission sensor to the outside, and
A cylindrical container that can be inserted into the hole and has an opening on the side surface, an inflatable tube installed in the cylindrical container, a receiving sensor that is inserted into the tube, and injecting and discharging liquid into the tube An injection / discharge pipe for receiving, a reception probe having a signal line for connecting the reception sensor to the outside, and
Pressurizing means for pressurizing the liquid in the transmission probe and the reception probe, and inflating the tubes of the transmission probe and the reception probe to contact the hole wall;
Means for generating a high frequency continuous wave in the transmission sensor;
Means for detecting a signal received by the receiving sensor;
Means for detecting the velocity and damping rate of the elastic wave propagating through the hole wall from the received signal;
A ground borehole logging apparatus characterized by comprising:   The ground borehole logging apparatus according to claim 2, further comprising a connecting rod having a predetermined interval between the transmission probe and the reception probe.   The ground borehole logging apparatus according to claim 3, wherein the length of the connecting rod is variable.   The ground borehole logging apparatus according to any one of claims 2 to 4, wherein the continuous wave is a pseudo-random wave.   The ground borehole logging apparatus according to any one of claims 2 to 5, wherein the frequency of the continuous wave is variable. The ground borehole logging device according to any one of claims 2 to 6 is inserted into a hole in the ground,
Pressurize the liquid of the transmitting probe and the receiving probe to bring the tube into contact with the hole wall,
A borehole logging in the ground characterized by detecting the signal received by the receiving sensor when the transmitting sensor generates a high-frequency continuous wave and detecting the velocity and attenuation rate of the elastic wave propagating through the hole wall Method.   8. The ground borehole logging method according to claim 7, wherein the transmitting probe and the receiving probe connected by the connecting rod are inserted into the same hole.   The ground borehole logging method according to claim 8, wherein measurement is performed by changing the length of the connecting rod.   8. The ground borehole logging method according to claim 7, wherein the transmitting probe and the receiving probe are inserted into different holes.   The ground borehole logging method according to any one of claims 7 to 10, wherein the continuous wave is a pseudo-random wave.   The ground borehole logging method according to any one of claims 7 to 11, wherein the measurement is performed by changing the frequency of the continuous wave.