JP2018169282A - Construction material moisture content evaluation method - Google Patents

Abstract

To accurately and easily evaluate a moisture content in a particular diameter section where a moisture containing state has a large impact on an amount of surface moisture or the like.SOLUTION: A method includes previously obtaining relation between a parameter related to a shape at a particular particle diameter section and a moisture content regarding soil particles included in a construction material. The method includes letting the evaluation object construction material flow down in an evenly scattered state, photographing the construction material flowing down in the evenly scattered state, executing image analysis of image data obtained by photographing, thereby calculating a parameter related to the shape of one of the soil particles at the particular particle diameter section, and evaluating a moisture content at the particular particle diameter section of the evaluation object construction material on the basis of the relation between the parameter related to the shape and the moisture content.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for evaluating the moisture content of a construction material. Specifically, the construction material to be evaluated is uniformly dispersed and allowed to flow down, and the soil particles are obtained by imaging the flowing construction material and performing image processing. It is related with the method of evaluating the water content ratio based on the shape about the soil particle contained in a specific particle size classification.

  In addition to general construction work, especially in CSG (Cemented Sand and Gravel) dams and concrete dam constructions, it is important to properly grasp the moisture content of the construction materials used in order to improve construction quality. is there. Various methods suitable for the measurement environment are used as a method for evaluating the water content ratio that is generally performed. For example, by using a drying oven or a microwave oven to dry a sample that contains moisture, the moisture content of the sample can be determined based on the difference between the weight before and after drying. This is a method of determining the amount of water using a moisture meter, a near infrared moisture meter, etc.

  However, the method of measuring the amount of water using a drying furnace has a problem that it takes a long time to determine the result because it takes a long time (for example, 24 hours) to dry the sample. In addition, the method of drying a sample using a microwave oven has an advantage that a result is obtained in a short time compared with a measurement method by furnace drying, but since it is a manual work, there is a problem that labor is required. there were.

  Further, the method of measuring the amount of water using a moisture meter has a problem that only the moisture present on the surface of the sample can be detected, and the measurement result is affected by the density of the sample at the time of measurement. Furthermore, in the case of a sample with a non-uniform particle size, even if the moisture content is measured using a moisture meter for a sample that is not classified (screened), the moisture content for each classification cannot be determined. It was. Therefore, various techniques for evaluating the moisture content of construction materials have been proposed (see Patent Documents 1 to 4).

  The technique described in Patent Document 1 relates to a method and system for managing the surface water amount of the ground material in real time, and determines the water content ratio of the ground material mixed with various particle sizes continuously supplied to the construction site. Measure continuously, extract a part of the supplied ground material every predetermined time to detect the particle size distribution, calculate the water content ratio for each predetermined particle size according to the particle size distribution from the water content ratio of the ground material, The surface water amount of the ground material is estimated in real time based on the water content ratio for each particle size. In this technique, the water content ratio of the ground material is measured based on the reflectance or transmittance of a predetermined wavelength when the ground material is irradiated with near infrared light.

  The technique described in Patent Document 2 is for measuring the particle size of a ground material in which granular materials having various particle sizes are mixed. A predetermined amount of the ground material is loaded in a lidless container, A predetermined amount of ground material is distributed over the entire bottom surface of the container by vibration, and a dispersed image of the ground material in the container is taken from above the container. Then, the particle size of the ground material is measured from the captured dispersion image.

  The technique described in Patent Document 3 is for managing the particle size by grasping the content ratio of the entire granular material from the image of the granular material, collected at a predetermined collection site, and continuously supplied. In order to manage the granular quality of the granular material, an input means for inputting an extrudate image of the granular material, a detecting means for detecting the outline of the granular material in the extrude image, and the granular material from the outline of each granular material A calculation means for obtaining an area and calculating an area ratio of a granular material having a predetermined particle diameter or more with respect to an area of the entire target material of the rolled-out image as a particle size index, and a particle size index of the coarsest sample and the finest sample of the granular material And a determination means for comparing the particle size index of the granular material continuously supplied with the particle size index of the coarsest sample and the finest sample to determine the particle quality of the supply material. That.

  The technique described in Patent Document 4 is a granular material particle size specifying method for specifying the particle size in a sample in which granular materials having various sizes and shapes are mixed, and the sample is obtained by an optical system means. Capturing an image and creating an input image, applying a Laplacian Gaussian function to the input image to perform wavelet transform, creating a wavelet image, and applying a preset threshold to the wavelet image Performing a binarization process to create a binarized image, using the binarized image to calculate granular material information including at least the size and shape of the granular material, and granular material information And creating a particle size distribution curve of the sample.

JP2015-105898A Japanese Patent Laying-Open No. 2015-179044 JP 2010-249553 A JP 2011-106923 A

  By the way, when measuring the ratio of water contained by classifying soil particles (hereinafter referred to as the water content ratio, the water content ratio and the water content are not clearly distinguished in the present invention), particularly in the fine particle content, If the proportion of water contained is small, the soil particles are dispersed uniformly, so even with the technique using the image processing described above, the water content can be determined appropriately. However, in the case of a fine granule containing a large proportion of water, there is a high possibility that soil particles will stick together and aggregate formation will occur, and an accurate water content ratio may not be obtained.

  In particular, when determining the unit water amount of concrete, the present situation is that correction based on the particle size measurement result in the actual plant or on-site is not performed. For this reason, for example, in the case of a dam construction site, in the case of a material containing a large amount of fine particles, the unit water amount varies greatly and the construction quality may be deteriorated.

  In this respect, it has been difficult to say that the technique described in each of the above-mentioned patent documents can measure an accurate water content ratio. With the technology that continuously measures the moisture content using near infrared light, etc., it can measure only the moisture content of several hundred micrometers or less from the surface of the measurement object, and if the color of the measurement object changes, the color change As a result, the measurement results are often affected, and the accuracy of surface water volume estimation is reduced.

  In addition, if a material to be subjected to particle size measurement is vibrated and imaged by a technique in which the material is uniformly dispersed on the bottom of the container, only the material present on the surface can be imaged. Further, depending on the moisture content of the material, the particles adhere to each other and come close to each other, so that it becomes difficult to grasp the outline of the soil particles, and the accuracy of the image processing is lowered. Also in this case, since the particle size distribution of the material to be measured cannot be accurately grasped, the construction quality may be deteriorated.

  The water content ratio evaluation method for a construction material according to the present invention has been proposed in view of the above-described circumstances. The construction material to be evaluated is uniformly dispersed and flowed down, and the flowing construction material is imaged to perform image processing. Assuming that the shape of the soil particles is evaluated and that the water content ratio is evaluated for each particle size category, the moisture content is accurately and easily determined, especially in the particle size category where the water content has a large effect on the surface water content. An object of the present invention is to provide a method for evaluating the moisture content of construction materials that can be evaluated.

  The construction material moisture content evaluation method according to the present invention has the following features in order to achieve the above-described object. That is, the water content ratio evaluation method for a construction material according to the present invention uniformly disperses and flows down the construction material to be evaluated, measures the particle size by imaging the flowing construction material and performing image processing, Assuming that the water content ratio is evaluated based on the particle size classification of the soil particles, the water content ratio is evaluated by the following procedure.

  Prior to the evaluation of the water content ratio, the relationship between the parameters relating to the shape and the water content ratio in a specific particle size category is acquired in advance for the soil particles contained in the construction material. Then, the construction material to be evaluated is allowed to flow down in a uniformly diffused state, the construction material flowing down in a uniformly diffused state is imaged, and the captured image data is subjected to image analysis, so that the soil of a specific particle size category is analyzed. A parameter related to the shape of one particle is calculated, and the water content ratio in a specific particle size classification in the construction material to be evaluated is evaluated based on the relationship between the parameter related to the shape and the water content ratio. .

  In this method for evaluating the moisture content of a construction material, the shape-related parameter in a specific particle size category is at least one of the average area of soil particles, the major axis of soil particles, the minor axis of soil particles, and the number of soil particles. Is possible.

  The specific particle size classification can be soil particles of less than 5 mm.

  According to the water content ratio evaluation method for a construction material according to the present invention, the construction material to be evaluated is uniformly dispersed and allowed to flow down, and the shape of the soil particles is evaluated by imaging the flowing construction material and performing image processing. However, since it is assumed that the water content ratio is evaluated for each particle size category, it is possible to prevent the overlapping of construction materials and to increase the accuracy of particle size analysis.

  In particular, for a specific particle size category in which the water content has a significant effect on the surface water content, etc., the relationship between the shape-related parameter and the water content ratio is acquired in advance, and the relationship between the parameter and the water content ratio is obtained. Thus, by evaluating the water content ratio in a specific particle size category in the construction material to be evaluated, the water content ratio of the construction material can be accurately evaluated. And construction quality can be improved by evaluating the moisture content of a construction material correctly in this way.

The block diagram of a water content ratio evaluation apparatus. The schematic diagram which shows schematic structure of the apparatus group for making a construction material flow down and imaging. Explanatory drawing which shows the relationship between the moisture content of soil particles and agglomeration. The graph which shows the correlation of the average area of a soil particle, and a water content ratio.

  Hereinafter, an embodiment of a water content ratio evaluation method for construction materials according to the present invention will be described with reference to the drawings. 1 to 4 illustrate a method for evaluating the water content ratio of a construction material according to an embodiment of the present invention. FIG. 1 is a block diagram of a water content ratio evaluation apparatus, and FIG. FIG. 3 is an explanatory diagram showing the relationship between the water content ratio of soil particles and agglomeration, and FIG. 4 is a graph showing the correlation between the average area of soil particles and the water content ratio. is there.

<Outline of evaluation method for moisture content of construction materials>
The construction material moisture content evaluation method according to the embodiment of the present invention uniformly distributes and flows down the construction material to be evaluated, images the construction material flowing down, and performs image processing to form the shape of the soil particles. Assessing the water content ratio for each particle size category, for example, for a specific particle size category for which agglomeration is a concern, the water content ratio is evaluated in consideration of agglomeration. is there. That is, as shown in FIG. 3, if the water content of the soil particles is small, the soil particles are dispersed, and if the water content of the soil particles is high, the soil particles tend to aggregate. 3A shows the state of the soil particles when the moisture content is low, and FIG. 3B shows the state of the soil particles when the moisture content is high.

<Water content ratio evaluation device>
The water content ratio evaluation apparatus 100 measures the water content ratio of a construction material, disperses the construction material uniformly and flows down in the vertical direction, and evaluates the shape of soil particles by imaging the flowing construction material. As shown in FIG. 1, the apparatus includes a supply means 10, a diffusion flow-down means 20, an imaging means 30, a particle size division analysis means 40, and a specific particle size division water content evaluation means 50. Yes.

  In addition, each means is comprised from the logic circuit which has the software which exhibits the function, or the logic circuit which has an equivalent function by being performed by hardware, such as a single or several member for exhibiting each function, or CPU etc. Is done.

<Supply means>
The supply means 10 is a means for supplying construction materials. As shown in FIG. 2, the supply means 10 is transported by a hopper 11 that receives a CSG material diverted from a conveyance path (not shown), a belt feeder 12 that conveys the CSG material received by the hopper 11, and a belt feeder 12. And a vibration device (not shown) that thins and smoothes the CSG material.

  The diffusion flow-down means 20 is a means for uniformly diffusing the construction material supplied from the supply means 10 to flow down in the vertical direction. The diffusion flow-down means 20 includes a plate-like screen member 21 as shown in FIG.

  The diffusion flow-down means 20 is not limited to the member configuration as shown in FIG. 2, and any apparatus may be used as long as the construction material supplied from the supply means 10 can be uniformly diffused and flow down. For example, a device having a cylindrical housing, a cylindrical shape, a triangular pyramid shape, a quadrangular pyramid shape, a conical shape, or a combination thereof, housed inside the housing, and vibrations that vibrate the diffusion portion You may comprise from an apparatus.

<Imaging means>
As shown in FIG. 2, the imaging unit 30 is a unit for imaging the construction material that is uniformly diffused by the diffusion flow-down unit 20. Although not shown, the imaging means 30 is constituted by a digital camera provided with an imaging lens system, an imaging element, an image data transmission interface, and the like. An illuminating device for illuminating the construction material to be imaged may be included as a component of the imaging means 30.

  In this embodiment, since the imaging is performed with the screen member 21 constituting the diffusion flow-down means 20 as a background, the digital camera is in the vicinity of the lower part of the diffusion flow-down means 20 at a position where the construction material flowing down does not contact (collision). It is installed. Further, in order to increase the accuracy of particle size classification analysis, the imaging means 30 (digital camera) may be installed at a plurality of locations. Moreover, it is preferable to use the material of the color in which the screen member 21 becomes clear with contrast with the color tone of the construction material to image.

<Particle size classification analysis means>
The particle size classification analysis means 40 is a means for analyzing the particle size classification according to the shape of the soil particles contained in the construction material by performing image analysis on the image data captured by the imaging means 30. For example, the particle size classification analysis unit 40 includes a personal computer (PC) and image analysis software, and performs image analysis based on image data received from the imaging unit 30 by the function of the image analysis software installed in the personal computer. Then, the particle size classification of the soil particles contained in the construction material to be analyzed is analyzed.

<Analysis of soil particle shape>
Any known technique may be used for the image analysis, but basically, based on the image data, the outline of the soil particles contained in the construction material is recognized and the average area of the construction material is analyzed. A technique is used. Instead of using the average area as a parameter for analyzing the shape of the soil particles contained in the construction material, the major axis of the soil particles, the minor axis of the soil particles, the number of soil particles, and the parameters calculated from these are used. It may be used. The particle size classification can be obtained by analyzing the shape of the soil particles contained in the construction material.

<Specific particle size classification water content ratio evaluation means>
The specific particle size classification water content ratio evaluation means 50 is a means for evaluating the water content ratio in a specific particle size classification in the construction material to be evaluated based on the relationship between the shape-related parameter and the water content ratio. That is, as shown in FIG. 4, there is a correlation between the water content ratio of the soil particles having a specific particle size category (for example, less than 5 mm) and the average area of the soil particles, and the correlation equation is established. The specific particle size category water content evaluation means 50 calculates (evaluates) the water content ratio of the soil particles of the specific particle size category using this correlation equation. The following correlation formula is an example of a correlation formula for calculating the water content ratio of soil particles having a specific particle size classification (for example, less than 5 mm), and other correlation formulas may be used.

W ₅ = A × S ₅ + B ... correlation formula where
W ₅ : Water content ratio of soil particles in a section of less than ₅ mm S ₅ : Average area of soil particles in a section of less than ₅ mm A, B: Coefficients calculated by calibration

<Water content of the entire construction material>
In the water content ratio evaluation method for construction materials according to the present invention, the water content ratio is evaluated for soil particles having a specific particle size category (for example, less than 5 mm). This is because there is a possibility that agglomeration may occur in the soil particles of the particle size category, and the water content ratio of the soil particles in a specific particle size category is evaluated by evaluating the influence of the aggregation as the shape of the soil particles. This is because it can.

  Therefore, in order to obtain the water content ratio of the entire construction material, the soil content of a specific particle size classification (for example, less than 5 mm) is used for the water content ratio evaluation method according to the present invention. The water content may be evaluated by an appropriate method.

<Analysis of particle size classification>
Hereinafter, the analysis procedure of the particle size classification for the construction material will be described. The analysis of the particle size classification is realized by the function of the particle size classification analysis means 40. Specifically, a regression equation is created for each particle size category by performing multiple regression analysis using construction materials whose particle size distribution is known, and the image analysis result of the construction material to be analyzed is created in the created regression equation. Substituting the explanatory variables calculated from the above, calculate the analysis target mass rate for each particle size category, and use the calculated analysis target mass rate for each particle size to analyze the particle size category of the construction material that is the analysis target .

  The analysis of the particle size classification is roughly divided into six steps. The first step is a step of calculating a soil particle average minor axis (Di) and a total projected area (Si) for each particle size category in the construction material using a construction material having a known particle size distribution. In the second step, the total projected area (Si) for each grain size is divided by the total projected area (ΣSi), which is the sum of the total projected areas (Si) for each grain size, so that the projected area ratio ( This is a step of calculating (Si / ΣSi). The third step uses construction materials with known particle size distributions and divides the total mass (Mi) for each particle size category by the total mass (ΣMi), which is the sum of the total mass (Mi) for each particle size category. This is a step of calculating the mass ratio (Mi / ΣMi) by making it dimensionless. The fourth step performs multiple regression analysis with the objective variable as mass ratio (Mi / ΣMi) and the explanatory variables as soil particle average minor axis (Di) and projected area ratio (Si / ΣSi), and returns for each particle size category. It is a process of creating an expression. A regression equation for each particle size category, which is the basis of the particle size category analysis, is created by the first step, the second step, the third step, and the fourth step.

  In the fifth step, the analysis target soil particle average minor axis (Di) and the analysis target projected area ratio (Si / ΣSi) calculated from the image analysis result of the construction material to be analyzed are substituted into the created regression equation. This is a step of calculating the analysis target mass ratio (Mi / ΣMi) for each particle size category. The sixth step is a step of analyzing the particle size classification of the construction material to be analyzed using the analysis target mass ratio (Mi / ΣMi) of each particle size calculated in the fifth step. By this sixth step, the particle size classification of the construction material to be analyzed can be analyzed.

  Further, in the fourth step, by adding the reciprocal (1 / Si) of the projected area absolute quantity as an explanatory variable, the particle size can be analyzed more accurately. In this case, in the step of calculating the analysis target mass ratio (Mi / ΣMi) (fifth step), the projection area absolute amount calculated from the image analysis result of the construction material to be analyzed is used as a value to be substituted into the regression equation. Calculation is performed by adding the reciprocal (1 / Si).

<Analysis algorithm for particle size classification>
Moreover, it is preferable that the regression formula used for analysis of a particle size division updates data according to construction progress. A specific particle size analysis algorithm will be described. The regression equation used in the present embodiment is an equation for analyzing the particle size division of the construction material to be analyzed, and includes an objective variable, an explanatory variable, and a correlation coefficient for each particle size division.

  As described above, the objective variable of the regression equation used in this embodiment is the mass ratio Y = Mi / ΣMi, and the explanatory variables are X1 = soil particle average minor axis Di and X2 = projected area ratio Si / ΣSi. is there. Further, the reciprocal (1 / Si) of the absolute amount of the projected area may be added as an explanatory variable. For example, a regression equation is created for each of the particle size D80 (mm), the particle size D40 (mm), the particle size D20 (mm), the particle size D10 (mm), and the particle size D5 (mm). By substituting the explanatory variable calculated from the image analysis result of the construction material, the particle size classification of the construction material to be analyzed is analyzed. Note that the regression equation described above is an example, and the particle size classification may be analyzed by a regression equation in which variables are changed.

DESCRIPTION OF SYMBOLS 100 Water content ratio evaluation apparatus 10 Supply means 11 Hopper 12 Belt feeder 20 Diffusion flow down means 21 Screen member 30 Imaging means 40 Particle size division analysis means 50 Specific particle size division water content ratio evaluation means

Claims (3)

For the soil particles contained in the construction material, obtain in advance the relationship between the shape-related parameters in the specific particle size classification and the water content ratio,
Let the construction materials to be evaluated flow down in a uniformly diffused state,
Imaging construction materials flowing down in a uniformly diffused state,
By analyzing the captured image data, parameters related to the shape of one soil particle of a specific particle size category are calculated,
Based on the relationship between the shape-related parameters and the water content ratio, the water content ratio in a specific particle size category in the construction material to be evaluated is evaluated.
A method for evaluating the water content ratio of a construction material.   The shape-related parameter in the specific particle size classification is at least one of an average area of soil particles, a major axis of the soil particles, a minor axis of the soil particles, and the number of soil particles. The moisture content evaluation method of the construction material as described.   The method for evaluating the moisture content of a construction material according to claim 1 or 2, wherein the specific particle size classification is soil particles of less than 5 mm.

Images