JP3205697B2 - AE generation position measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an underground A
The present invention relates to an apparatus for measuring the position of an E signal.

For example, when an experiment for predicting a slope collapse is performed, this type of apparatus is used to locate the position of a surface on which a slide collapse occurs within the slope (No. 29, 1994). Soil Engineering Research Presentation "Waveguide for AE Slope Failure Prediction").

[0003]

2. Description of the Related Art In FIG. 6, a deep hole 602 perpendicular to the boring is formed by drilling from the ground surface 600, and a waveguide rod (waveguide) 604 is inserted into the deep hole 602.

The waveguide rod 604 is made of solid metal, and AE sensors 606 are attached to both ends of the waveguide rod 604 in advance.

After the waveguide rod 604 is inserted, the deep hole 60
2 is filled with water, sand, etc.
Sensor 606 is embedded.

[0006] The AE signal generated in the ground is a waveguide rod 6.
When it reaches 04, it is transmitted through the inside of the waveguide rod 604 toward both ends thereof, and reaches the AE sensors 606 on the ground surface side and underground side.

Both AE sensors 606 output a detection signal corresponding to the AE signal, and the depth position at which the AE signal is generated is determined by both AE sensors.
It is calculated using the time difference between the detection signals output from the sensors 606 (the difference between the times when the AE signals reach both AE sensors 606).

[0008]

Conventionally, since a large-scale boring work is performed to bury a waveguide, a large amount of cost and time are required.

Also, the waveguide is often left buried, in which case the expensive AE sensor (underground side) is buried.

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an apparatus which can start measurement quickly at a small cost and can collect an expensive AE sensor.

[0011]

In FIG. 1, an apparatus according to the present invention is mounted on only a surface of a hollow rod 10 which is inserted into the ground and collects AE signals from the ground, AE for detecting the AE signal collected by the hollow rod 10
A sensor 12; delay amount calculating means 14 for calculating a delay amount of a subsequent wave component with respect to an initial wave component of the AE signal from a detection signal of the AE sensor 12;
A position calculating means for calculating the position of the signal generation source from the delay amount obtained by the delay amount calculating means.

(Operation) The hollow rod 10 is inserted from the ground surface into the ground. Since the AE sensor 12 is not attached to the underground side of the hollow bar 10, the hollow bar 10 can be inserted into the ground by a pile driving operation. For this work, heavy machinery for civil engineering can be used.

After the operation is completed, the AE sensor 12 is mounted only on the surface side of the hollow rod 10.

When an AE signal is generated in the ground, this AE signal
The signal is collected by the hollow bar 10 and the AE collected by the hollow bar 10
The AE sensor 12 detects the signal.

The delay amount calculating means 14 calculates the delay amount of the subsequent wave component with respect to the initial wave component of the AE signal from the detection signal of the AE sensor 12, and the position calculating means 16 determines the source of the AE signal source in the length direction of the hollow rod 10. The position is calculated by the delay amount calculating means 14.
It is calculated from the delay amount obtained in.

After the measurement is completed, the AE sensor 12
The hollow bar 10 is also pulled out and collected (it is inexpensive and may be left as it is for the next time).

[0017]

FIG. 2 shows an embodiment of the present invention, in which an AE sensor 12 is attached to a side surface of one end of a hollow rod 10.
Is attached.

The detection signal of the AE sensor 12 is supplied to an amplifier 200
, Is amplified, and given to the waveform processing device 202.

The output of the waveform processing device 202 is provided to a generation position processing device 204, and the output of the generation position processing device 204 is taken into a computer main body 206. A keyboard 208, a display 210, and a printer 212 are connected to the computer main body 206.

The hollow rod 10 is sunk into the ground without the AE sensor 12 attached. This pile driving work can be performed efficiently and in a short time by diverting heavy machinery for civil engineering work.

After the stake-out operation is completed, the AE sensor 12 is moved to the side of the head of the hollow rod 10 exposed on the ground surface as shown in FIG.
And connected to the amplifier 200 of FIG.

When an AE signal is generated in the ground and reaches the hollow bar 10, the signal is guided to the AE sensor 12 through the hollow bar 10.

In the AE sensor 12, a detection signal corresponding to the AE signal is obtained.
The signal is amplified by 0 and output to the waveform processing device 202.

FIG. 4 shows AE signal generation positions a, b, c,
d and e are shown, of which the position a is the deepest and the depth becomes shallower in the order of the positions b, c, d and e.

Here, the AE signal is divided into an initial wave component and a subsequent wave component that lags behind the initial wave component, and the amount of delay of the subsequent wave component with respect to the initial wave component is proportional to the depth at which the AE signal is generated.

FIG. 5A shows the waveform of the AE signal generated at the position e, and FIG. 5B shows the waveform of the AE signal generated at the position a. The delay amount of the wave component depends on the difference in the depth between the position e and the position a. For example, in a pipe whose material and dimensions are shown in FIG. 4, the distance between positions a, b, c and e is 50c as shown in FIG.
In the case of m, the specific numerical value of the delay time Δt is described as shown in FIG.

The waveform processing device 202 calculates the delay amount of the subsequent wave component with respect to the initial wave component, and the generation position processing device 204 calculates the depth at which the AE signal is generated from the delay amount calculated by the waveform processing device 202. You.

The processing of the computer main body 206 is started in accordance with an instruction given from the keyboard 208, and the time of slope failure and the like are predicted from the depth calculated by the generation position processing device 204 and the number of occurrences of the AE signal.

The prediction result is displayed graphically on the display 210 or printed out on paper by the printer 210.

When the device is removed, the AE sensor 12
Is detached from the amplifier 200 and removed from the hollow rod 10, and finally, the hollow rod 10 is pulled out of the ground using a heavy equipment for civil engineering.

As described above, according to the present embodiment, since the AE sensor 12 is not mounted on the underground side of the hollow rod 10, boring work is not required, and therefore, the work of burying the hollow rod 10 can be performed quickly. And the costs are significantly reduced.

Further, since the AE sensor 12 is mounted only on the ground surface side, the sensor mounting work becomes easy.

Further, since the expensive AE sensor 12 is exposed on the surface of the ground, it is easy to collect the AE sensor 12 and the AE sensor 12 is not buried and left.

The hollow rod 10 can be easily recovered by being pulled out using a heavy equipment for civil engineering, and can be reused next time.

[0035]

As described above, according to the present invention, since the waveguide is a hollow rod and the AE sensor is not mounted on the underground side, boring is not required in the construction work of the waveguide. The cost is significantly reduced and the construction time is significantly reduced.

Further, since the AE sensor is attached at one place, the operation is easy, and the number of expensive AE sensors is one, so that the cost of the apparatus is also reduced.

Further, A is applied only to the ground side of the waveguide.
Since the E sensor is attached, collection of the sensor is extremely easy, and the sensor can be repeatedly used without being abandoned in the ground.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram illustrating a configuration of an embodiment.

FIG. 3 is an explanatory diagram of an operation of detecting an AE signal.

FIG. 4 is an explanatory diagram of an AE signal generation position.

FIG. 5 is an explanatory diagram of a waveform of an AE signal.

FIG. 6 is an explanatory diagram of a conventional technique.

FIG. 7 is a pipe in which the material and dimensions shown in FIG.
FIG. 9 is an explanatory diagram of specific numerical values of the delay time Δt when an interval between positions a, b, c, and e is 50 cm.

[Explanation of symbols]

 Reference Signs List 10 hollow rod 12 AE sensor 200 amplifier 202 waveform processing device 204 generation position processing device 206 computer main body 208 keyboard 210 display 212 printer

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Claims (1)

(57) [Claims] 1. A hollow rod (10) which is inserted into the ground to collect an AE signal from the ground, and an AE signal which is attached to only the surface side of the hollow rod (10) and which is collected by the hollow rod (10). Sensor (1)
2), a delay amount calculating means (14) for calculating a delay amount of a subsequent wave component with respect to an initial wave component of the AE signal from a detection signal of the AE sensor (12), and an AE signal generation in a length direction of the hollow rod (10). An AE occurrence position measuring device, comprising: a position calculating means (16) for calculating the position of the source from the delay amount calculated by the delay amount calculating means (14).