JP2681735B2 - Geological survey method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for investigating the geology of a ground to be surveyed by drilling a survey hole in the ground.

[0002]

2. Description of the Related Art Conventionally, as a method for investigating the geology of the ground, there have been a method of directly observing the ground and a method of cutting out a part of the ground to obtain a sample and observing the sample. In tunnel excavation work, etc., it is not possible to directly visually observe the ground to be surveyed beforehand. Therefore, drill the target ground with a boring machine to collect a rod-shaped boring core and observe this core. Often, advanced boring surveys for geology were adopted. For example, Isao Toriumi “New Architectural Engineering 6
"Geotechnical engineering" (published on February 28, 1979, 1st edition, 5th edition), several borings were performed on one site, and the soil columnar diagram was placed at a predetermined position to obtain a cross-sectional view of the ground. The techniques to obtain are described.

However, the above-mentioned boring survey has the following problems. The poorer the geology of the surveyed ground, the more difficult it will be to collect observable boring cores, and the harder it will be to collect the parts of the boring core that you really want to know during construction, such as faults and fracture zones. There was a problem that the information of was not obtained. Since a special boring machine is required to obtain a boring core, it is not possible to carry such a special machine into the face of a tunnel or prepare for drilling.
There is a problem that it takes time and labor. During the boring work, the excavation work of the tunnel itself is forced to be interrupted, and thus there is a problem that the survey cost is generally high. Since the size of the boring core as a sample is smaller than the ground to be surveyed, there is a problem that a highly reliable geological survey cannot be performed.

Therefore, there is a method of taking an image of the inner wall surface of the bored survey hole with a borehole camera, instead of collecting and observing the bore core. This is because the borehole camera is inserted into the bored survey hole, the surrounding wall surface is imaged, the shade and color tone of the obtained image are observed with the naked eye, and classification / identification of geology or the strike of cracks is performed. The slope is being analyzed.

Then, when analyzing the strike inclination of a discontinuous surface such as a surface of a crack or a boundary surface of different geology from the obtained image, the discontinuous surface of the crack or the like on the obtained image is manually operated one by one. It was traced at and the strike inclination was calculated by hand calculation. However, in the conventional geological survey method using such a borehole camera, there are problems that the judgment criteria are ambiguous, the subjectivity of the observer is apt to be influenced, the individual difference of the observer is likely to intervene, and the reproducibility is low. is there.

Further, even in the case of observation by the same person, there is a problem that the reproducibility is low because the judgment criteria are ambiguous and have variations. In addition, for classification and identification of geology by observation,
The problem is that some experience and specialized knowledge are required. In addition, analyzing the strike and dip of a discontinuous surface such as a crack surface or a boundary surface of different geology requires a manual trace and an analysis of the strike and dip by manual calculation, and thus there is a problem that time and labor are required. . In particular, there is a problem that as the number of discontinuous surfaces such as cracks increases, more time and labor are required for analysis. In order to improve the problem that the reproducibility of observation results is low and the problem that experience and expertise are required, computer-aided image recognition technology (for example, a technique that identifies minerals by image processing is used. There are known JP-A-1-307638 and JP-A-62-80780 and JP-A-4-290186, which are techniques for identifying a specific area in an image.
This technique is a technique for identifying the mineral substances and geology to be surveyed, and identifies by comparing the image data of the survey target with the reference data.

[0007]

When using a core boring machine to excavate a borehole as in the prior art,
As mentioned above, it is not possible to solve the problem that it takes time and labor to carry a dedicated machine such as a core boring machine into the face of a tunnel or to prepare for drilling. The work of drilling the borehole is different from the excavation work of the tunnel itself, and the problem that the excavation work of the tunnel itself is interrupted during the boring work and the construction efficiency is poor cannot be solved yet.

In view of the above, it is an object of the present invention to provide a geological survey method capable of eliminating the need for a core boring machine by drilling a small-diameter survey hole to be a borehole as in the blast hole drilling operation. I am trying. As a geological observation method, we decided to use computer-based image recognition technology.

[0009]

According to a first aspect of the present invention, there is at least two geological survey methods at a predetermined distance from the ground to be surveyed.
A plurality of small-diameter cylindrical inspection holes are bored, and the inner wall surface of each of the inspection holes is continuously imaged along one measurement line set parallel to the axis to obtain image data, and each of the images is obtained. The data are compared while shifting one pixel by one pixel in a predetermined range on the measurement line, the shift amount when each image data is best matched is calculated, and based on the calculated shift amount and the interval between the inspection holes. The feature is that the inclination of the boundary surface of the stratum between the survey holes is obtained two-dimensionally and three-dimensionally.

In the geological survey method according to a second aspect of the present invention, at least two small-diameter cylindrical survey holes are formed in the ground to be surveyed at a predetermined interval, and the inner wall surface of each survey hole is parallel to the axis. Image data is obtained by continuously imaging along one set measurement line, and each image data is compared while shifting by one pixel in a predetermined range on the measurement line. It is characterized in that the shift amount at the time of coincidence is calculated, and the inclination of the crack surface between the inspection holes is obtained two-dimensionally or three-dimensionally based on the calculated shift amount and the interval between the inspection holes. To do.

[0011]

According to the invention of claim 1, at least two small-diameter cylindrical inspection holes are bored at a predetermined interval in the ground to be inspected, and the inner wall surface of each of the inspection holes is set parallel to the axis. Image data of the inner wall surface along the measurement line can be obtained by continuously imaging along the measurement line of the book. Such image data is obtained from each inspection hole. Then, the image data obtained from the inspection holes are compared with each other in the following manner. That is, the respective image data are compared while being relatively shifted by one pixel in a predetermined range on the respective measurement lines, and when the respective image data best match, the respective image data have corresponding characteristics. Determine that
Then, by calculating the relative shift amount in that state, the strata having the corresponding features,
Obtain the amount of axial deviation between the survey holes. Based on this deviation and the spacing between the survey holes, the inclination between the survey holes of the boundary surface of the stratum having the corresponding characteristics is obtained two-dimensionally and three-dimensionally. In the case of two survey holes, the inclination of the stratum between the survey holes can be obtained two-dimensionally, and in the case of three or more survey holes, the boundary surface of the stratum between the survey holes. The slope of can be obtained three-dimensionally. In addition, since the inspection hole has a small diameter, a machine for tunnel excavation can be used, and a machine dedicated to core boring is not required.

The invention of claim 2 is different from the case of claim 1 only in that the inclination of the surface of the crack is obtained, not the inclination of the formation, and the other aspects are the same as in the first aspect. is there.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The geological survey method of the present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is a block diagram showing the configuration of the embodiment, and FIG. 2 is a block diagram of the image processing apparatus of the embodiment.

As shown in FIGS. 1 and 2, in parallel with the work of drilling a blast hole using a drilling machine for tunnel construction,
The same drilling machine is used to drill three small-diameter inspection holes 11A, 11B, 11C applicable as simple boreholes.

A borehole camera 12 as an image pickup device is inserted into each of the inspection holes to pick up an image of the inner wall surface, which is input to the expansion processing device 14 to obtain a developed image of the inner wall surface, which is once stored on a magnetic tape or the like. At this time, drilling information such as drilling speed, sound and torque in the drilling work is also recorded in association with the image data. Note that one of the specific techniques of the expansion processing in the expansion processing device 14 is disclosed in Japanese Patent Laid-Open No. 3-1
It has already been shown in detail in 32590.

The image data of the developed image recorded on the magnetic tape thus obtained is input to the image processing apparatus 10. The drilling information is input to the drilling information section 16. The image processing apparatus 10 performs preprocessing such as image quantization processing, filter processing, and feature amount extraction processing and outputs pre-processed digitized image data, and based on the digitized image data. Parameter extraction processing to extract crack parameters, inclination calculation processing to calculate strike inclination,
Based on the image processing unit 15 that performs image processing such as calculation of RQD, determination processing of rock quality and weathering degree, and the result obtained by this image processing unit 15 and the drilling information of the drilling information unit 16, A forward prediction unit 17 that performs a forward prediction process such as a geological structure prediction process, a rock grade prediction process, and a spring water condition determination process.

Even if the inner wall surface of the inspection hole is not entirely imaged by the borehole camera, a measurement line parallel to the axis of each inspection hole is set along the inner wall surface, and the image data on this measurement line is digitized. The brightness distribution in the obtained image data is measured. As shown in FIG. 3, such a brightness distribution on the measurement line can be obtained for each of the three survey holes, and the shift amount between these brightness distributions can be calculated to obtain the strike slope of the corresponding stratum. it can. One of the concrete methods of this treatment is shown in detail in Japanese Patent Application No. 4-296048 previously proposed by the applicant.

In Japanese Patent Application No. 4-296048, a cylindrical hole is bored in the ground to be investigated, and at least two measurement lines parallel to the axis of the hole are set on the inner wall surface of the hole, and at least the above-mentioned The inner wall surface on the measurement line is continuously imaged by an imaging device, the image data digitized from the image data on the measurement line in the images corresponding to the both measurement lines is obtained, and each of the obtained image data is set to a predetermined value. Image data on both measurement lines are compared with each other while shifting by one pixel in the range, and a state in which the image data on both measurement lines best match each other is searched for. Then, when the shifts are made so as to best match each other, the geology on both measurement lines can be determined to be the same geology having corresponding features. Therefore, when the shift amount in the best matching state is calculated, this shift amount indicates the deviation of the boundary surface between the strata on both measurement lines. The deviation of the boundary surface of this stratum is referred to as the axial deviation.

Further, a cylindrical hole is bored in the ground to be surveyed,
At least two measurement lines parallel to the axis of the hole are set on the inner wall surface of the hole, at least the inner wall surface on the measurement line is continuously imaged by an imaging device, and measurement is performed on an image corresponding to the both measurement lines. While shifting the digitized image data obtained based on the image data in the predetermined range on the line pixel by pixel, the sum of squares of the differences in the image data between both measurement lines is calculated, and the sum of squares is determined to be the minimum. Is calculated,
The geology between the two measurement lines that are shifted by the shift amount may be determined to be the same geology. In this way, the axial displacement of the boundary surface of the strata on both measurement lines can be obtained.

In addition, by making a cylindrical hole in the ground to be surveyed,
First and second measurement lines parallel to the axis of the hole are set on the inner wall surface of the hole, and the inner wall surface on the first and second measurement lines is continuously imaged by an imaging device, Set a range to be examined on the first measurement line in the image corresponding to the measurement line, and a range corresponding to the range on the second measurement line in the image corresponding to the second measurement line and the range before and after the range. The same range is set, and the sum of squares of the differences between the digitized image data on the first measurement line and the digitized image data on the second measurement line is set to be three times as large as the first range. so,
It is also possible to calculate by shifting one pixel at a time, obtain a shift amount that minimizes the sum of squares, and determine that the geology between the two measurement lines deviated by the shift amount is the same geology. In this way, the axial displacement of the boundary surface of the strata on both measurement lines can be obtained.

In addition, a cylindrical hole is bored in the geology to be investigated,
On the inner wall surface of the hole, at least three measurement lines parallel to the axis of the hole are set, and at least the inner wall surface on each of the measurement lines is continuously imaged by an image pickup device, and in an image corresponding to each of the measurement lines. While shifting the digitized image data in the predetermined range on the measurement line pixel by pixel, calculate the sum of squares of the difference between the digitized image data between the measurement lines, and search for the state where the sum of squares is the minimum. . Then, when the shifts are made so as to best match each other, the geology on both measurement lines can be determined to be the same geology having corresponding features. Therefore, when the shift amount in the best matching state is calculated, this shift amount indicates the geological deviation on both measurement lines. In this way, it is possible to obtain the axial deviation of the boundary surface of the formation between the image data.

In the above application, three measurement lines were set on the inner wall surface of a single survey hole and the luminance distribution on each measurement line was processed. However, in this embodiment, three measurement lines are processed. Drilling inspection holes, setting one measurement line for each inspection hole, digitizing image data on these measurement lines to obtain image data, and processing the luminance distribution based on the image data Is. Outer diameter is 25 mm ~
In order to use a borehole camera of about 30 mm, the diameter of the survey hole may be about 36 mm to 42 mm, so that there is no need for a dedicated boring machine and there is an advantage that it can be shared with tunnel excavation.

By extracting each pixel of each image data for each wavelength band of R, G, B and performing A / D conversion, extraction is performed without losing information such as brightness, hue and saturation of the original image. And convert it into digitized image data. The digitized image data may be temporarily stored in a storage medium such as a magnetic disk. As the digitized image data, only the brightness information may be used as the brightness distribution curve.

When comparing the brightness distribution curve with the actual geological distribution, if a discontinuity such as a crack exists on the inner wall surface of the survey hole, the brightness of that part may be lower than the brightness of other parts. Since it is known, it can be seen that the depressed portion in the brightness distribution curve corresponds to the crack.

Further, it has color information peculiar to optical properties (refractive index and reflectance) depending on the geology, and the R (red), G (green), B (blue) components and the geology in a color image. There is a correlation. Therefore, by separately preparing the correlation data between the R, G, B components and the geology in each pixel,
It can be seen that the areas with high brightness correspond to granite and the areas with low brightness correspond to porphyry.

For example, granite mainly composed of quartz or feldspar generally shows a white color, while porphyrite, which often exists as an intrusive body, contains colored minerals such as amphibole and pyroxene. Therefore, it often shows a dark green color.

A process of judging a crack based on the digitized image data will be described below with reference to FIG. FIG. 3 is a brightness distribution curve in which the brightness distribution on the measurement line on the image data corresponding to the measurement line set on the inner wall surface of each hole is extracted based on the image data obtained by digitizing the image data. FIG. 3A shows a hole 11A,
3B is a brightness distribution curve of the hole 11B, and FIG. 3C is a brightness distribution curve of the hole 11C.

First, a range of depth for n pixels centered on a certain depth where the brightness is lowered is set as the window W to be analyzed. Then, for any of the R, G, and B images, between the two holes, for example, the holes 11A and 11B,
While shifting the digitized image data of the corresponding pixels between the measurement lines of both holes by one pixel with reference to the drop portion of the brightness distribution curve existing at the depth d on the measurement line of the hole 11A, The sum of squares S12 of the differences in luminance between the pixels of the measurement line is sequentially calculated, and the sum of squares S12 (0) to S12 is calculated.
Find (n-1). At this time, the value calculated between the pixels corresponding to a certain crack is the smallest compared to the value calculated between the other pixels, and therefore, by obtaining the shift amount δ ₁₂ when the calculated value becomes the minimum, It is possible to determine the relative position of the crack between the holes 11A and 11B.

Similarly, the shift amount δ ₁₃ between the holes 11A and 11C is obtained. In the above calculation formula, the shift amount may be obtained from the minimum value of the sum of squares S12 as shown in Formula 1. However, as shown in Formula 2, the shift amount is divided by the average to make it dimensionless, and then the difference is calculated. The shift amount may be obtained from the minimum value of the sum of squares S12 ', or, as shown in Expression 3, the sum of squares S12 "is obtained based on the deviation from the average value and the shift amount is obtained from the minimum value. Further, the degree of correspondence of the luminance distribution may be obtained by a method of obtaining a correlation coefficient or covariance without obtaining the sum of squares.

[0030]

(Equation 1)

[0031]

(Equation 2)

[0032]

(Equation 3)

Here, the position d of the hole 11A on the measurement line,
Based on the shift amounts δ ₁₂ , δ ₁₃ , it is possible to determine the three-dimensional coordinates of the intersection of the crack surface and each of the holes 11A, 11B, 11C. For example, when each hole is formed in the horizontal direction, the axial direction of the hole may be set as the X axis, the horizontal axis orthogonal to the X axis may be set as the Y axis, and the vertical axis may be set as the Z axis. Then, the inclination of the surface of the crack on the plane including the two holes 11A and 11B can be two-dimensionally determined from the distance between the holes 11A and 11B and the shift amount δ ₁₂ . Similarly, the inclination of the crack surface between the holes 11A and 11C can be obtained from the distance between the holes 11A and 11C and the shift amount δ ₁₃ . Then, from the normal vector of the crack surface specified by the three holes, the strike inclination of the crack surface is also obtained. In this way, the three holes 11
The inclination of the surface of the crack in the space surrounded by A, 11B and 11C can be obtained three-dimensionally.
The above processing is realized by the inclination calculation processing function of the image processing unit 15.

The calculation of the sum of squares S ₁₂ , S ₂₃ , and S ₃₁ of the digitized luminance differences between pixels is performed by dividing the digitized luminance for each measurement line of each hole by its average value. It is possible to obtain a more stable calculation result with less variation by using the dimensionless data or the data obtained by taking the difference from the average value.

The above description is for the case where the inclination of the boundary surface of the stratum or the surface of the crack is obtained two-dimensionally and three-dimensionally. In the following, a process of identifying geology based on the digitized image data will be described. R,
Similarly to the above, for any of G and B images, a brightness distribution curve based on digitized image data existing at the depth d on the measurement line of the hole 11A between the measurement lines of the two holes 11A and 11B. Based on the depressed part of
While shifting the digitized image data of the corresponding pixels between the measurement lines of both holes by one pixel at a time, the holes 11A, 11B
Sum of squares S of digitized luminance differences between pixels between the measurement lines
Ask for twelve. Similarly, the sum of squares S23 of the digitized luminance differences between the pixels between the measurement lines of the holes 11B and 11C, the hole 11
Quantitative identification of geology by calculating the sum of squares S31 of the digitized luminance differences between pixels between C and 11A measurement lines and obtaining the shift amount when each value becomes the minimum. It can be carried out.

Further, the distribution of the value of the ratio of R, G, B components of the digitized image data on the measurement line of each hole is obtained,
While shifting the image data digitized between the measurement lines of the two holes pixel by pixel, the sum of squares of the difference in the ratio values between the corresponding pixels is calculated, and the shift amount when those values are minimum is calculated. By determining, it is possible to minimize the change in the image data (luminance, hue, saturation, etc.) due to the fluctuation or variation of the light quantity and identify the geology.

Since crystalline rocks have different optical properties depending on the type of crystals constituting the rocks, and also have different optical properties inside and between grain boundaries of the crystals, the R, G, and B images are different. By investigating the detailed characteristics of the brightness distribution based on the digitized image data, it is possible to classify the rock types and properties in more detail. By such processing, it is possible to identify whether or not rocks of the same type in the ground of the same survey object. That is, the distribution of the same type of rock can be grasped.

The information obtained in this manner is combined with the drilling information such as drilling speed, drilling sound and torque during drilling work to predict the ground condition in front of the cutting face in great detail. It becomes possible to do. For example, it is possible to predict the geological structure and the grade of the bedrock, and also the condition of spring water.

[0039]

According to the first aspect of the present invention, at least two small-diameter survey holes are drilled in the ground to be surveyed, and an image of the inner wall surface of each survey hole is picked up by the image pickup device, and the image data thereof is obtained. By analyzing based on the digitized image data, the inclination of the geological boundary surface is obtained, and the ground condition of the survey target is mechanically determined with high reproducibility without depending on the subjectivity or experience of the surveyor. be able to.

By shifting the image data of the two survey holes, it is possible to know the deviation of the boundary surface of the geology having the corresponding features between the survey holes. Based on this deviation and the distance between the two survey holes, it is possible to two-dimensionally determine the inclination of the boundary surface of the stratum in the surveyed ground. Further, by combining image data of three or more survey holes, it is possible to three-dimensionally determine the inclination of the boundary surface of the stratum in the surveyed ground.

Further, since the small-diameter survey hole does not require a dedicated boring machine, a machine for tunnel excavation can be used, so that the survey hole as a borehole can be drilled in parallel with the blast hole drilling. It is possible to obtain an image for investigation in a short time without interrupting the tunnel excavation work itself.

According to the second aspect, the inclination of the crack surface in the ground to be investigated can be obtained two-dimensionally and three-dimensionally.

[Brief description of the drawings]

FIG. 1 is a diagram showing a block configuration of a survey device used for a geological survey method of the present invention.

FIG. 2 is a block diagram showing a configuration of an image processing device of the investigation device.

FIG. 3 is a diagram showing a luminance distribution curve on a measurement line of image data imaged at each inspection hole.

[Explanation of symbols]

 11A, 11B, 11C Inspection hole 12 Borehole camera (imaging device) 15 Image processing unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-132590 (JP, A) JP-A 64-39492 (JP, A) JP-A 1-307638 (JP, A) Written by Isao Chokai. "New Architectural Engineering 6 Geotechnical Engineering", 1st edition, 5th edition, Morikita Publishing Co., Ltd., February 28, 1979, p. 6-7

Claims (2)

(57) [Claims] 1. At least two small-diameter cylindrical inspection holes are bored at a predetermined interval in the ground to be inspected, and the inner wall surface of each of the inspection holes is made into one measurement line set parallel to the axis. Image data is obtained by continuously capturing images along with each other, and each image data is compared while being shifted pixel by pixel in a predetermined range on the measurement line, and a shift amount when each image data best matches is calculated. Then, based on the calculated shift amount and the distance between each survey hole, the inclination of the boundary surface of the stratum between the survey holes is obtained two-dimensionally and three-dimensionally. 2. At least two small-diameter cylindrical inspection holes are bored at a predetermined interval in the ground to be inspected, and the inner wall surface of each of the inspection holes is made into one measurement line set parallel to the axis. Image data is obtained by continuously capturing images along with each other, and each image data is compared while being shifted pixel by pixel in a predetermined range on the measurement line, and a shift amount when each image data best matches is calculated. Then, based on the calculated shift amount and the distance between the inspection holes, the inclination of the crack surface between the inspection holes is obtained two-dimensionally and three-dimensionally.