JPH07117532B2 - Method to analyze the structure of bedrock, concrete, etc. - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analysis method for accurately grasping the shape and distribution of cracks and bubbles existing in stone and concrete.

[0002]

2. Description of the Related Art As a first example, a drilling hole having a predetermined inner diameter is formed in front of a face to be investigated in order to check the presence or absence of a crack in a rock or the like, its size, and the generation density. A CCD camera equipped with a conical mirror is inserted into the drill hole, and while keeping the inside of the hole at a constant brightness and rotating the CCD camera at a constant speed, the entire circumference of the hole wall is photographed and the position of the camera, that is, the depth is sequentially measured. There is a method in which the state of cracks is taken out as an electric signal over a desired range by changing the image and the image is processed.

Further, the durability of concrete is determined by the number (distribution) of bubbles generated in the concrete and the size thereof. In other words, it relates to how much volume can be absorbed in the concrete layer when the volume of the concrete changes due to temperature changes in summer and winter and the products of alkali-aggregate reaction (alkali silica reaction). It is known that the buffer that absorbs the change in volume is air bubbles in concrete. Since the main factor that governs the durability of concrete is air bubbles, it is necessary to clearly understand the state of the air bubbles. Currently, the AS parameter is used to measure the parameters of the air bubble structure in concrete.
TM (American Society of Testing Materials) -C457 (a method of measuring the parameters and air volume of the air bubble system of hardened concrete by microscope) and the linear traverse method (second example) and the modified point counting method (Third example) Among them, the ASTM C457 linear traverse method is to finish the end faces of a plurality of sampled samples by polishing, traverse with a microscope at regular intervals on the polishing plane, and to remove bubbles observed on the traverse line. The total amount, the sum of the lengths of the chords from which the bubbles are cut, and the respective data such as the total traverse distance on the sample surface are obtained, and by quantitatively analyzing this, the air amount relative to the sample volume is expressed as a percentage ratio. It was done like this.

In the modified point counting method, a sample preliminarily sampled is placed on a sample table which can be freely moved in two directions, that is, a horizontal direction and a direction perpendicular to the horizontal direction by a manual screw. The rotation is stopped at a fixed position each time the screw makes one rotation, and the stop frequency is counted.

Further, in addition to the above (fourth example), the polished surface of a concrete sample sampled is infiltrated with cyanoacrylate to which a fluorescent dye is added, and by irradiating it with ultraviolet rays, the luminance distribution of the light emitting portion is kept constant. There is means for performing image processing by binarizing with a threshold value, for example, Japanese Patent Application Laid-Open No. 2-77648 (Applicant).

[0006]

However, the means for investigating the cracks in the rock mass in the first conventional example is to irradiate the wall surface of the excavation hole with light and carry out the investigation in a very ordinary manner using a CCD camera. Therefore, the captured image depends on the performance (resolution) of the CCD camera. However, even if the performance is improved, it may not be possible to make a clear judgment depending on the state of cracks, and it may not always be possible to highly evaluate it. or,
In all of the second, third and fourth conventional examples, the sampled sample is prepared by arranging the test surface and then inspected by a predetermined method. Therefore, the sample is easily damaged at the time of sampling. It is difficult to detect the end face close to the true state. Therefore, the present invention aims to provide a means capable of detecting a sample without sampling it.

[0007]

[Means for Solving the Problems] After applying cyanoacrylate or methyl methacrylate to which a fluorescent dye has been added into a test hole formed in a layer to be tested and allowing the tissue to infiltrate,
After arranging the surface of the test hole, irradiate it with ultraviolet rays to emit light,
Image processing is performed by binarizing the light emission distribution at that time with a constant threshold value.

[0008]

[Function] By applying cyanoacrylate or methylmethacrylate to the inner wall of the test hole, it penetrates into the cracks of the rock or concrete layer or into the air bubbles. At this time, by irradiating with ultraviolet rays, the location of cracks and bubbles can be clearly identified by the emission of the fluorescent dye, and by binarizing this by image processing and cutting below a certain brightness, cracks and bubbles can be visualized. .

[0009]

The present invention will be described in detail below. To carry out the method of the present invention, it is divided into a test hole, measurement of the area of a region to be inspected, ultraviolet irradiation method and determination of a threshold value. Speaking of the case where the layer to be tested is concrete, first of all, in order to provide a test hole, a boring of a predetermined diameter is carried out to a predetermined depth in the concrete layer at the work site, and the inner core (columnar concrete block) is removed, After that, a solution of cyanoacrylate (adhesive known by the trade name of Aron Alpha or Cyanobond) or methylmethacrylate (adhesive) to which a fluorescent dye is added is applied to the peripheral wall of the test hole except the core by another tool. The solution of the adhesive has excellent permeability, but since it is colorless and transparent, its location is unknown when it is used, so a fluorescent dye is added to it, but by doing so, the life of the adhesive can be improved. There is a drawback that the time (time to reach coagulation) is shortened, and here an improved one is used. Any method may be used to apply the above-mentioned applied cyanoacrylate or methyl methacrylate to the peripheral wall of the test hole, but it can be applied throughout by repeatedly applying it several times, and the solution penetrates deeply into the large and small bubbles existing in concrete. After that, the outer circumference of the test hole is polished with a separately prepared tool and the excess adhesive solution that adheres to the surface is carefully ground and scraped off. It is necessary to finish the test hole surface with sufficient care, as the bubbles of # 1 may emerge.

Next, the area measurement will be described. A CCD camera is inserted into the test hole and rotated 360 (°), and the position is measured.
By changing the (depth), the area can be easily measured from the relationship between the rotation angle and position of the CCD camera, but in reality the magnification of the image is small, so the image signal from the CCD camera must be enlarged. If the magnification is set in advance by displaying on a display screen such as a cathode ray tube, the area of the measuring portion can be obtained.

Next, in order to examine the state of bubbles in the test hole,
C and a light-emitting element (means) that generates ordinary visible light and ultraviolet rays
Insert a device equipped with a CD camera, irradiate visible light on the wall of the test hole, take a picture of the entire surface of the wall of the test hole with a CCD camera, and display the state on the display surface as shown in Fig. 1 for observation. In addition, by irradiating the light emitting device with ultraviolet rays having a specific wavelength, only the image of the light spots emitted by the ultraviolet rays is emitted from the adhesive solution containing the fluorescent dye.
Is taken out from the CCD camera and displayed on the display surface.

Next, in order to quantitatively image-analyze the state of the bubble structure on the inner wall of the test hole by the image processing device and calculate the geometrical parameters, it is premised that the target image is binarized. For binarization, a threshold value is set and given as an apparatus constant, the minimum value of the emission intensity (luminance value) of the fluorescent dye filled in the bubbles in the concrete layer is determined. More specifically, in order to observe the entire image, as described above, the visible light is applied to the inner wall of the test hole, and the CCD is
An image containing aggregate a, sand b, etc. is taken by the camera and can be observed on the display surface as shown in Fig. 1. For image analysis, for example, a sample of ultraviolet rays with a specific wavelength of 3.650Å is sampled. It must be an image obtained by illuminating the inner wall of the hole. Since the irradiation effect in that case largely depends on the wavelength and the intensity of the ultraviolet rays, care should be taken so that sufficiently strong fluorescence can be obtained from the inner wall surface of the test hole. The fluorescent image from the adhesive obtained by the irradiation of ultraviolet rays passes through the CCD camera, and an image with large bubbles c (high brightness part) and small bubbles c '(low brightness part) is reproduced on the display surface as shown in FIG. As compared with FIG. 1, the image is completely different, and the shape, size distribution density, etc. of the space existing in the concrete layer, that is, the bubble portion, is clearly shown. Thus, the brightness difference between the air bubbles and the cement paste is remarkable, but there are some air bubbles that do not provide sufficient brightness, but the amount thereof is extremely small when viewed from the whole. The brightness distribution between A and B on the scanning line of the above image is
FIG. 3 shows one-dimensionally extracted data on the time axis, and these data are input to the image processing apparatus. In that case, a threshold value (for example, 94) is set in advance in the image processing apparatus, and by binarizing, a fluorescent point having a constant luminance value or less is set to the threshold value 94.
When the image is reproduced by the signal obtained in this way, a screen with only bubbles having a certain size or more is obtained as shown in FIG. 4, and at the same time, the parameter of the bubble tissue is calculated from this binarized image, and The amount of bubbles existing in a certain volume is calculated by sequentially shifting the AB line at regular intervals on the screen until it reaches a predetermined area. As described above, the number of bubbles other than the amount of air by taking the luminance distribution on the time axis one-dimensionally, the length of the surface of the test hole, the lateral shape factor, the equivalent diameter (equivalent circle in area value and Parameters such as diameter at the time of performing) and their basic statistics can also be automatically calculated by the arithmetic processing function provided in the image processing apparatus.

Although the above has described an example of quantitative analysis of bubbles existing in concrete, the present invention is not limited to this, and the appearance of rocks at a building installation site, that is, the presence or absence of cracks, their size, distribution, density, etc. As in the case of concrete, the adhesive liquid of cyanoacrylate or methylmethacrylate, to which a fluorescent dye is added, infiltrates into the gaps and shows that state, and in rocks as well as in coarse rocks such as sandstone layers You can see the situation. The present invention is different from observing a core taken out from a test hole drilled in rock as in the past or quantitatively examining it by image analysis, unlike a core that is easily broken, It was designed to investigate the state of the inner wall surface of the.

[0014]

As described above, according to the present invention, at a work site, a test hole having a certain depth is provided, and an adhesive having a high permeability, which contains a fluorescent dye, is applied to the inner wall portion of the test hole to make the surface excessive. By removing the adhesive that has adhered to it and irradiating it with ultraviolet light, the fluorescence from the adhesive that has penetrated into the minute gaps is detected, and image analysis is performed from this, so the cores sampled as before are examined. The reliability is higher than that of. Also, regarding image processing, each state can be examined in exactly the same manner as before by irradiating ultraviolet rays, taking out as an image signal with a CCD camera and reproducing it on a display.

[Brief description of drawings]

FIG. 1 is an image schematic diagram of an inner wall surface of a test hole obtained by visible light.

FIG. 2 is a schematic diagram of an image obtained by irradiating the above-mentioned image with ultraviolet rays.

FIG. 3 is a characteristic diagram showing a luminance distribution state on the line AB in the above.

FIG. 4 is a schematic diagram of an image in a state in which FIG. 2 is binarized.

[Explanation of symbols]

 a Aggregate b Sand c Large air bubble c'Small air bubble

Claims (1)

[Claims] 1. An adhesive of cyanoacrylate or methyl methacrylate in which a test hole is preliminarily drilled in a layer to be tested such as rock or concrete and a fluorescent dye is added to the inner wall of the test hole.
After the solution is applied and infiltrated and solidified, the inner wall of the above
Excessive adhesive solution adhered to the surface and solidified is removed by polishing.
After that, the surface is irradiated with ultraviolet rays to cause the fluorescent dye to emit light, which is then observed, and the luminescence distribution at that time is binarized by a certain threshold value by an image processing method so that the rock mass and concrete are How to analyze the organization such as.