JP2941150B2 - Rock property measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for objectively measuring rock properties.

[0002]

2. Description of the Related Art Conventionally, as a method of measuring and classifying the properties of a rock mass, a measurer hits a target rock mass with a rock hammer, listens to the sound at that time,
Whether the sound is clear, slightly muddy, somewhat muddy, muddy or extremely muddy, and the result of visual observation with the naked eye Based on this, classification of the properties of the rock mass was performed. Based on the observation results obtained in this way, the method of supporting the rock when forming a cavity such as a tunnel in the rock was determined. However, according to the method described above, the properties of the rock are measured and classified based on the hearing, vision, and experience of the measurer, so that individual differences occur in the measurement results due to differences in the measurers, and accurate measurement results are obtained. Has the problem that it is necessary to perform the above measurement by a technician who has sufficient experience, and even if the same person performs the measurement, stable reproducibility can be obtained due to differences in physical condition and environment at the time of measurement. There was a problem that can not be. In view of the above, the applicant disclosed in Japanese Patent Application Laid-Open No. 2-179470 a technique for analyzing the frequency of vibration transmitted to the rock to measure the properties of the rock.

[0003]

According to this technique, even if there are individual differences or physical conditions of the measurers, the measurement results do not vary and stable reproducibility can be obtained. Since only rock mass can be measured, in order to measure the properties of a wide range of rock mass, the impact and measurement are repeated many times,
It was necessary to make a comprehensive judgment by examining the measurement results.

Accordingly, an object of the present invention is to provide a measuring device capable of measuring an averaged property of a rock in a predetermined range by one impact.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in the rock property measuring apparatus according to the first aspect of the present invention, a striking means for striking a rock mass to be measured; A first vibration detecting means for detecting the vibration generated by the impact in the vicinity of the impact position and outputting the first vibration signal as a first vibration signal; and a second vibration detecting means for detecting the vibration generated by the impact in a position other than the vicinity of the impact position. A second vibration detecting means for outputting the first vibration signal as a second vibration signal;
Frequency analyzing means for analyzing the frequency of the vibration signal to obtain a first frequency distribution characteristic and a second frequency distribution characteristic;
Pattern extracting means for comparing a frequency distribution characteristic of the first frequency distribution characteristic with a second frequency distribution characteristic and extracting a change pattern between the two characteristics, wherein the pattern extraction means comprises a first frequency distribution characteristic and a second frequency distribution characteristic. The calculating means calculates the ratio between the spectral intensities of the first and second vibration signals for each frequency based on the characteristics.

[0006]

According to the present invention, the vibration generated by hitting the rock to be measured is changed to the vicinity of the hitting position,
It is detected at one or more other positions and converted into electric signals, and the signals are subjected to frequency analysis to obtain the frequency distribution characteristics of the vibration at each position.

When these frequency distribution characteristics are compared with each other to extract a change pattern between the two characteristics, the change pattern is specified by the average properties of the rock from the vicinity of the struck position to other detected positions. Thus, the properties of the range from the vicinity of the struck position of the rock to the other detected position can be measured and classified according to the change pattern.

For example, high-frequency vibrations are hardly attenuated if the average properties of the rock from the vicinity of the impacted position to other detected positions are hard, but high-frequency vibrations are attenuated if the properties are soft. There is a feature that is easy.

Then, at each frequency, by comparing the intensity of the spectrum of the vibration signal in the vicinity of the hit position with the intensity of the spectrum of the vibration signal at other positions, it is possible to determine which frequency of the vibration signal is easily attenuated It is possible to know a characteristic pattern such as whether or not it is difficult. For the target rock mass, the properties of the rock mass are determined in advance by a conventional method or the like, and a change pattern of the frequency distribution characteristic is extracted using the apparatus of the present invention, and a correspondence diagram between the change pattern and the corresponding rock mass property is obtained. By obtaining the (calibration diagram), the properties of the unknown rock mass are measured, classified, and further determined based on the change pattern obtained by using the apparatus of the present application and the calibration diagram. You can do it.

That is, in the rock property measuring apparatus of the present invention, the rock to be measured is hit by the hitting means, the first vibration detecting means detects near the hitting position, and the second vibration is detected at other positions. And outputs them as first and second vibration signals, respectively. further,
The first and second vibration signals are analyzed by frequency analysis means to obtain first and second frequency distribution characteristics. Then, the change pattern is extracted by comparing the first and second frequency distribution characteristics by the pattern extracting means. The change pattern thus obtained shows a specific pattern depending on the property of the rock, and the property of the rock can be measured and classified based on the pattern.

Further, the pattern extracting means is arithmetic means for calculating the ratio of the spectral intensity of the first and second vibration signals for each frequency based on the first frequency distribution characteristic and the second frequency distribution characteristic, Based on the strength ratio, rock properties were measured and classified.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view showing an apparatus for measuring rock properties according to the present invention. In the drawing,

Reference numeral 1 denotes a rock hammer made of metal which strikes a rock A. Reference numeral 2 denotes a first piezoelectric element which is provided in the lock hammer 1 and detects a vertical vibration of the lock hammer 1 and outputs a first vibration signal. The second piezoelectric element detects vibration in a direction perpendicular to the surface (vibration in the direction of hitting with the lock hammer 1) and outputs a second vibration signal.

4 is a preamplifier for amplifying the first and second vibration signals, and 5 is an A / D conversion circuit for converting the amplified first and second vibration signals into first and second digital signals. , 6 are memories for storing the converted first and second digital signals, and 7 is a fast frequency Fourier transform of the first and second digital signals stored in the memory 6 to obtain a first frequency spectrum distribution. This is an FFT processor that obtains a characteristic Spec. 1 and a second frequency spectrum distribution characteristic Spec.

8 is a spectrum intensity S2 (f) at the frequency f of the second frequency spectrum distribution characteristic Spec.
Ratio S2 (f) / S1 with the spectrum intensity S1 (f) of the first frequency spectrum distribution characteristic Spec.1 at the same frequency f
(f) to calculate the ratio SR (f) of the spectral intensities,
This is an arithmetic circuit that obtains a frequency distribution characteristic SR of a ratio of spectrum intensities in all frequency ranges. Reference numeral 9 denotes a liquid crystal display device, and the first and second frequency spectrum distribution characteristics Sp
A spectrum display section 91 for displaying ec.1 and Spec.2 and a spectrum ratio display section 92 for displaying a frequency distribution characteristic SR of the spectrum ratio are provided.

Reference numeral 10 denotes a standard memory for storing data of standard patterns of frequency distribution characteristics of spectrum ratios corresponding to various rock properties, and reference numeral 11 denotes comparison of the frequency distribution characteristics SR of the ratio of spectrum intensities with the standard patterns. By
A property judging circuit for judging the property of the bedrock, and 12 is a judgment display device for displaying the judgment result.

The first piezoelectric element 2 does not need to be built in the rock hammer 1 and may be mounted on the rock surface near the hit point. Either way, when you hit the rock,
The vibrations at different positions P1 and P2 of the rock should be detected as the first vibration signal and the second vibration signal.

A case where the properties of a rock mass are measured by using the rock mass property measuring apparatus having the above configuration will be described below. First, the position P1 where the rock A is hit with the rock hammer 1 and the second
Position P2 for mounting the piezoelectric element 3 of
Is mounted on the surface of the rock. Next, the rock hammer 1 strikes the determined position P1 of the bedrock A, so that the vibration generated at the position P1 is changed to the first position.
And the first vibration signal is obtained by detecting with the piezoelectric element 2, and the vibration generated at the position P2 is detected by the second piezoelectric element 3 and obtained as the second vibration signal. The first and second vibration signals thus obtained are temporarily stored in the memory 6 as digital signals via the preamplifier 4 and the A / D conversion circuit 5.

The digital signal in the memory 6 is subjected to frequency analysis by fast Fourier transform by the FFT processor 7 to obtain a first frequency spectrum distribution characteristic Spec. 1 from the first vibration signal, and a second frequency spectrum distribution characteristic Spec. 1 from the second vibration signal. To obtain the frequency spectrum distribution characteristic Spec. The frequency spectrum distribution characteristics Spec. 1 and Spec. 2 are displayed on the spectrum display section 91 of the liquid crystal display 9. In the frequency analysis in the FFT processor 7, it is preferable to remove a frequency component caused by vibration inherent in the lock hammer 1.

Then, the second operation is performed by the arithmetic circuit 8.
From the frequency spectrum distribution characteristics Spec. 2 and the first frequency spectrum distribution characteristics Spec. 1, a frequency distribution characteristic SR having a ratio of spectrum intensities is obtained. Thereby, a local factor (for example, variation due to the impact strength) due to the impact is corrected. The frequency distribution characteristic SR of the ratio of the spectrum intensities indicates the pattern of amplification and attenuation of the amplitude for each frequency between the two points P1 and P2, and indicates the average of the rock A in the section to be measured. It can be said that it is one kind of frequency spectrum distribution characteristics representing various properties.

Next, the frequency distribution characteristic SR of the ratio of the spectrum intensities is displayed on the spectrum ratio display section 9 of the liquid crystal display device 9.
2 is displayed. By comparing the frequency distribution characteristic SR of the ratio of the spectral intensities with the spectral data of the reference standard pattern stored in the standard memory 10, the overall properties of the rock A can be determined.

The spectrum data of the standard pattern is prepared based on a calibration chart as shown in FIG. 3 obtained by measuring in advance for each different geology at the site where the property is measured. That is, in several places of the rock mass to be measured, a conventional rock mass property measuring method, that is, a rock mass property determined by a measuring method based on hearing and visual observation and the like, and the rock mass property measuring device for the rock mass The calibration chart as shown in FIG. 3 is obtained based on the frequency distribution characteristics of the ratio of the spectrum intensities obtained by the measurement. If the rock mass between the two positions P1 and P2 is soft,
(A), a peak appears at a low frequency, and when hard, a peak appears at a high frequency, as shown in [D] of FIG. There are also other patterns such as [B] and [C]. For accurate measurement, it is desired that this calibration diagram be prepared for each site. Also, if there is a crack in the rock, the vibration is greatly attenuated at that part, so if you focus on a specific frequency and observe the change in the spectral intensity at that frequency at multiple locations, you can know the existence of the crack .

The first piezoelectric element 2 may not be provided on the lock hammer 1 and may be mounted at an arbitrary position P1 on the rock surface. At this time, the vicinity of the position P1 is hit with a normal lock hammer 1. Further, instead of the second and third piezoelectric elements 2 and 3 themselves being replaced by a microphone, a semiconductor pickup, or the like, a hitting sound or vibration may be detected. Further, instead of digital processing by the FFT processor 6, frequency analysis may be performed by analog processing to obtain frequency distribution characteristics. In the above embodiment, the first and second piezoelectric elements are used. However, three or more piezoelectric elements are arranged on the surface of the rock, and the properties of the rock which spreads in a plane by one impact are obtained. Can be determined.

[0024]

As described above, according to the rock property measuring apparatus of the present invention, the rock property of an arbitrary section of the rock to be measured is measured, and the overall property of the rock in the section is averaged. Since the properties are measured, even if there are local variations in the properties of the rock, an effect is obtained in which the properties of the rock that are averaged over the whole can be measured. In addition, the second position
By installing the vibration detection means, the property of the rock mass in a wide area can be measured at once and the result can be obtained immediately, so that the measurement work can be done in a short time, labor cost and process cost Thus, the effect of being efficient can be obtained. In addition, since the rock property measurement work is performed by frequency analysis of vibration, there is no difference in the measurement result even if the measurer is different, and even an inexperienced technician can obtain an accurate measurement result. The effect that it can be obtained is obtained. In addition, there is an effect that stable reproducibility can be obtained even if the physical condition of the measurer and the surrounding environment in the measurement work are different.

In such an operation, a correlation between a change pattern of the frequency distribution characteristic obtained by hitting the target rock and a rock property obtained by measuring the rock by a conventional method is obtained in advance. By doing so, it is possible to accurately determine the properties of the rock. Since the construction method of the support is determined based on the rock properties obtained in this manner, an appropriate construction method can be selected, and the effect of increasing safety and economy can be obtained. In this manner, even at a construction site or the like, a change in the properties of the rock mass can be detected at any time, and accordingly, it becomes possible to always carry out the optimum support work.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating the operation of a rock property measuring apparatus according to the present invention.

FIG. 2 is a block diagram of a rock property measuring apparatus according to the present invention.

FIG. 3 is a calibration diagram showing a change pattern of a frequency spectrum distribution characteristic that differs depending on rock properties.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rock hammer (hitting means) 2 1st piezoelectric element (1st vibration detection means) 3 2nd piezoelectric element (1st vibration detection means) 4 preamplifier 5 A / D conversion circuit (frequency analysis means) 6 memory (Frequency analysis means) 7 FFT processor (Frequency analysis means) 8 Arithmetic circuit (Pattern extraction means) 9 Liquid crystal display device 91 Spectrum display unit 92 Spectral ratio display unit 10 Standard memory 11 Property judgment circuit (Property judgment means) 12 Judgment display device

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G01N 29/00-29/28

Claims (1)

(57) [Claims] 1. A striking means for striking a rock mass to be measured, a first vibration detecting means for detecting a vibration generated by the striking near a striking position and outputting as a first vibration signal, A second vibration detecting means for detecting the vibration at a position other than the vicinity of the hitting position and outputting the vibration as a second vibration signal; and analyzing the first vibration signal and the second vibration signal to obtain a first vibration signal. Frequency analysis means for obtaining a frequency distribution characteristic and a second frequency distribution characteristic, and pattern extraction means for comparing the first frequency distribution characteristic and the second frequency distribution characteristic to extract a change pattern between the two characteristics. Wherein the pattern extracting means includes a first frequency distribution characteristic and a second frequency distribution characteristic.
A rock mass property measuring device, wherein the calculating means calculates a ratio of the intensity of the first and second vibration signals for each frequency based on the frequency distribution characteristic of the rock mass.