JPH0587784B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for objectively measuring the properties of rock in a predetermined area.

[Conventional technology]

Conventionally, the method of measuring and classifying the properties of rock in a predetermined area is to have a measurer percussion any part of the target rock area with a rock hammer at the site, listen to the sound, The properties of the rock in question were classified based on differences such as whether the sound was clear or muddy, and the results of visual observation with the naked eye.

[Issue to be solved]

However, according to the conventional method described above, the overall properties of the rock area are determined by percussing a part of the area with a predetermined extent with a rock hammer, so variations in the properties of the rock surface are not detected. There is also the problem that measurement errors due to Moreover, if the conventional method is used to measure the entire rock area in order to solve the above problem, the measurement operation takes a long time and is not efficient. Furthermore, since rock properties are measured and classified based on the auditor's hearing, vision, and experience, individual differences in measurement results occur due to differences in the operator, and it is necessary to have sufficient experience to obtain accurate measurement results. The problem is that you have to be an experienced engineer. In addition, there is also the problem that stable reproducibility cannot be obtained due to differences in physical condition or environment at the time of measurement, even if the measurement is performed by the same person. The measurement results obtained in this way determine the construction method for supporting when forming cavities such as tunnels in the bedrock, so inaccurate measurements may pose safety and economical problems. . Therefore, an object of the present invention is to provide a method for objectively measuring the average properties of rock in a predetermined area with accuracy and height reproducibility.

[Means to solve the problem]

The present invention has been made in view of the above-mentioned problems, and in the rock property measuring method according to the present invention, the rock mass area to be measured is divided into a plurality of regions, and in each division, the rock mass is struck and The frequency spectrum distribution characteristics in the section are determined by frequency analysis of the generated vibrations, the frequency spectrum distribution characteristics are normalized, and the normalized frequency spectrum distribution characteristics are added in all sections to obtain a composite frequency spectrum. The distribution characteristics were obtained, and the overall properties of the rock mass area to be measured were measured based on the synthesized frequency spectrum distribution characteristics.

[Effect]

According to the rock property measuring method according to the present invention,
The rock mass area to be measured is divided into multiple regions, and the frequency spectrum distribution in each division is determined by frequency analysis of vibrations generated by striking the rock mass. The frequency distribution characteristics obtained in this way exhibit specific distribution characteristics depending on the properties of the rock mass in question, so it is possible to measure and classify the properties of the rock mass in the relevant section using this frequency distribution characteristic. It can be done. By normalizing the frequency spectrum distribution characteristics in each section obtained in this manner, variations in the strength of vibration due to differences in striking conditions or differences in striking sections are corrected. Then, by adding the normalized frequency spectrum distribution characteristics in all sections to obtain a composite frequency spectrum distribution characteristic, variations in rock properties and noise components due to differences in impact sections are reduced. Then, the overall characteristics of the rock area to be measured are measured using the synthetic frequency spectrum distribution characteristics. In advance, the frequency distribution characteristics of the target rock mass are measured by frequency analysis of vibrations caused by impact, and the properties of the rock mass are determined using conventional methods, etc., and a correspondence diagram between the frequency distribution characteristics and the corresponding rock mass properties ( A calibration diagram) is obtained, and the overall properties of the rock mass are measured and classified based on the synthetic frequency spectral distribution characteristics obtained by the method for measuring rock mass properties according to the present invention and the calibration diagram, and further judgment is performed. It is also possible to do so.

【Example】

An embodiment of the rock property measuring method according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory diagram illustrating the rock mass measurement state according to the same embodiment, and FIG. 2 is a block diagram of a rock property measuring device used in the same embodiment. In the drawing, 1 is a metal rock hammer that strikes the rock A, 2 is a piezoelectric element that is installed inside the rock hammer 1 and detects the vertical vibration of the rock hammer 1 and outputs a vibration signal, and 3 is a piezoelectric element that outputs a vibration signal. A preamplifier that amplifies the vibration signal; 4 is an A/D conversion circuit that converts the amplified vibration signal into a digital signal; 5 is a memory that stores the converted digital signal; 6 is a high-speed Fourier converter for the digital signal in the memory 5; FFT processor to convert and obtain frequency spectral distribution characteristics,
7 is a liquid crystal display that displays the frequency analysis results; 8 is a standardization circuit that normalizes the frequency of the frequency spectrum distribution characteristics obtained by fast Fourier transform; and 9 is the storage of the normalized frequency spectrum distribution characteristics for each section. 10 is a standard memory storing data of standard patterns of frequency spectrum distributions corresponding to various rock properties; 11 is a stacking circuit that generates a composite distribution pattern by comparing the composite distribution pattern with the standard pattern; A property determination circuit for determining the properties of the rock mass, 1
2 is a determination display device that displays the determined results. In the rock mass property measuring method using the rock mass property measuring device having the above configuration, first, the rock mass A is divided into desired sections A1, A2, A
Classify into 3,...,An. Next, by hitting the section A1 of the rock A with the rock hammer 1, the vibration generated is detected by the piezoelectric element 2, and amplified by the preamplifier 3, and the amplified vibration signal is The A/D conversion circuit 4 converts the signal into a digital signal. The converted digital signal is temporarily stored in the memory 5, and the digital signal in the memory 5 is subjected to frequency analysis using fast Fourier transform by the FFT processor 6 to obtain the frequency spectrum distribution characteristic S1, and the result of this frequency analysis is displayed on the liquid crystal display. Display on 7. In the above frequency analysis, it is preferable to exclude frequency components caused by vibrations specific to the lock hammer 1. Then, the frequency of the frequency spectral distribution characteristic S1 is normalized by the normalization circuit 8 to obtain a normalized frequency spectral distribution characteristic S'1, thereby correcting variations due to impact strength and the like. The normalized frequency spectrum distribution characteristic S'1 is stored in the stacking circuit 9. Next, by hitting the section A2 of the rock mass A in the same manner as described above, obtain the frequency spectrum distribution characteristic S2 corresponding to the property in the section A2 of the rock mass A,
Furthermore, the normalized frequency spectrum distribution characteristic S'2 is determined and stored in the stacking circuit 9. At this time, in the stacking circuit 9, the normalized frequency spectral distribution characteristic S'1 and the normalized frequency spectral distribution characteristic S'2 are superimposed and synthesized. In this way, all sections A1, A2, A
3. Frequency spectrum distribution characteristics S1, S2, S3, ..., in each section in An,
Normalized frequency spectral distribution characteristics S'1, S'2, S'3, ..., obtained by obtaining Sn and normalizing these.
S'n is stored in the stacking circuit 9. Therefore, in the stacking circuit 9, the normalized frequency spectrum distribution characteristics S'1, S'2,
By overlapping the frequency components of S'3, . That is, the synthesized frequency spectrum distribution characteristic Sav
can be said to be a frequency spectrum distribution characteristic representing the average properties of the rock mass A to be measured. Therefore, the composite frequency spectrum distribution characteristic
The overall properties of the rock mass A can be determined by comparing Sav with spectrum data of a reference standard pattern stored in the standard memory 10. The spectral data of the standard pattern is prepared based on a calibration plane as shown in FIG. 4, which is obtained by pre-measurement for each different geology at the site where the properties are to be measured. That is, the properties of the rock mass determined at several locations on the rock mass to be measured by the conventional rock mass property measurement method, that is, the measurement method based on auditory and visual observation, and the properties of the rock mass determined at several locations on the rock mass to be measured. Based on the frequency spectrum distribution characteristics obtained by the measuring device, spectrum data of a calibration surface and a standard pattern as shown in FIG. 4 are obtained. For accurate measurements, it is desirable to create spectral data for the calibration plane and standard pattern for each site. Note that the preamplifier 3, A/D conversion circuit 4,
The memory 5, FFT processor 6, and liquid crystal display 7 may all be integrated into the handle of the lock hammer 1. Note that, instead of the piezoelectric element 2, a vibration detection means such as a microphone or a semiconductor pickup may be used, and instead of the digital processing by the FFT processor 6, analog processing is used to perform frequency analysis and obtain frequency distribution characteristics. It's okay.

【effect】

In this way, according to the rock mass property measurement method according to the present invention, the rock mass area to be measured is divided into a plurality of regions, the rock mass properties are measured in each division, and the results are standardized and stacked. and measure the overall properties of the rock mass.
Even if there are variations in the properties of the rock mass, the effect of being able to measure the overall averaged properties of the rock mass can be obtained. Moreover, according to this method, measurement results for a plurality of sections can be obtained immediately, so that the measurement work can be done in a short time and is effective in terms of labor costs and processes. The rock properties mentioned above are measured using vibration frequency analysis, so there will be no difference in the measurement results even if the measurer is different, and even an inexperienced engineer can get accurate results. This provides the advantage of being able to obtain measurement results. In addition, stable reproducibility can be obtained even if the physical condition of the person taking the measurement or the surrounding environment at the time of measurement is different. At this time, by obtaining a correlation in advance between the frequency distribution characteristics obtained by hitting the target rock mass and the rock mass properties obtained by measuring the rock mass using conventional methods, it is possible to accurately determine the rock mass properties. It is also possible to do so. Since the construction method of the support is determined based on the rock properties obtained in this way, an appropriate construction method can be selected, and the effect of increasing safety and economic efficiency can also be obtained. Therefore, even at a construction site, changes in the properties of the rock mass can be detected at any time, so it is possible to always construct optimal shoring.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram illustrating the rock mass measurement state according to an embodiment of the rock mass property measuring method according to the present invention, and FIG. 2 is a block diagram of a rock mass property measuring device used in the same embodiment. FIG. 3 is a diagram showing measurement data in each step of the same example, and FIG. 4 is a calibration diagram showing frequency spectrum distribution characteristics that vary depending on rock properties. A... Bedrock, A1, A2, A3,..., An...
Partition, S1, S2, S3,..., Sn... Frequency spectrum distribution characteristics, S'1, S'2, S'3,..., S'n
...Normalized frequency spectral distribution characteristics, Sav...
Synthetic frequency spectral distribution characteristics.

Claims (1)

[Claims] 1. Divide the rock area to be measured into multiple regions, and in each section, calculate the frequency spectrum distribution characteristics in the section by frequency-analyzing the vibrations generated by hitting the rock,
The frequency spectral distribution characteristics are normalized, the normalized frequency spectral distribution characteristics are added in all sections to obtain a composite frequency spectral distribution characteristic, and the rock area to be measured is determined by the composite frequency spectral distribution characteristic. A rock property measurement method characterized by measuring the overall properties of a rock.