JP6050729B2 - Method and system for measuring moisture content of ground material - Google Patents

Description

  The present invention relates to a method and system for measuring the moisture content of a ground material, and more particularly, to a method and system for measuring the moisture content of a ground material having various particle sizes.

  The quality of structures (especially strength) in the construction of embankments such as dams, seawalls (embankments), and other civil engineering structures using structural materials such as CSG (Cemented Sand and Gravel), cement improved soil, concrete, etc. From the viewpoint of managing the amount of water contained in the structural material, and the ground materials such as the CSG material, cement-modified soil base material, and aggregate (the mud of various particle sizes). It is sometimes required to measure and manage the amount of water contained in civil engineering materials that contain sand, gravel and other components. For example, from the viewpoint of material rationalization, there are variations in the particle size and water content of the raw materials at construction sites where structural materials are produced from the use of crushed materials, sand materials, gravel materials and other ground materials procured or generated near the site. Therefore, it is necessary to measure and monitor the moisture content of the raw material and the product (structural material) using the raw material and to control the quality of the structure (see, for example, CSG work in Non-Patent Document 1).

  In general, the amount of water (water content ratio or water content) contained in a ground material with various particle sizes is obtained from the mass lost when the ground material is dried in a constant temperature drying furnace at 110 (± 5) ° C. (Refer to non-patent document 2) However, since it takes 18 to 24 hours to dry the ground material in the drying furnace, there is a problem that this method can be performed only once / one day. The moisture content test method (see Geotechnical Society Standard JGS0122, Non-Patent Document 3) and the moisture content ratio that heats the ground material directly in a frying pan as a method for measuring moisture content more quickly. A test method (see Non-Patent Document 4) has been implemented. In addition, a method of measuring moisture content (moisture content or moisture content) by irradiating the ground material with radiation (neutron beam) and using a radioisotope (RI) instrument from the transmitted or reflected radiation (neutron beam) has been put into practical use. (See Patent Documents 1 and 2).

JP 56-049945 A JP 2009-121930 A Japanese Examined Patent Publication No. 61-061623 Japanese Patent Laid-Open No. 06-229917

Jyuji Yanagawa "New technology in dam business-trapezoidal CSG dam" published by Construction Industry Research Committee, Base Design Material, No. 136 Civil Engineering, published on March 20, 2008, Internet (URL: http://www.kenkocho.co.jp/html/136/sa_136.html) Geotechnical Society of Japan “Ground Material Testing Methods and Explanations”, Maruzen Publishing, November 2009, pp. 104-105 Geotechnical Society of Japan “Ground Material Testing Methods and Explanations”, Maruzen Publishing, November 2009, pp. 106-107 Dam Technology Center, “Taraki CSG Dam Construction and Quality Control Technical Data”, September 2007, pp. 4-19 JIS A1109 Fine aggregate density and water absorption test method JISA1110 Coarse aggregate density and water absorption test method

  However, the water content ratio test method using the microwave oven and the water content ratio test method using the frying pan can measure the water content in about 10 to 30 minutes, but the ground material supplied to the construction site can be used. There is a problem that it is only possible to measure the moisture content of the extracted part, and it is not possible to continuously measure the moisture content of the supplied ground material. For example, in the construction of a structure using crushed material, sand material, gravel material or other ground materials procured or generated near the site, the moisture content of the ground material with variations is measured as frequently as possible from the viewpoint of quality control. -It is required to check (see Non-Patent Document 1), and it is possible to monitor that the required quality is always satisfied by continuously measuring the moisture content of the ground material that is sequentially supplied from the procurement or generation site. Technology development is desired.

  On the other hand, the method of measuring the amount of water using an RI instrument is, for example, a large amount of ground material that is sequentially supplied to the construction site by installing the RI instrument in a transport path (such as a loading hopper) that transports the ground material. It can be expected to continuously monitor the amount of water (see Patent Documents 1 and 2). However, according to the inventor's preliminary experiment, since the RI instrument measures the moisture content of the ground material in a sealed state, the ground material tends to block or adhere to the sealed measuring section. There is a possibility that the moisture content of the attached ground material is always measured, and there is a problem that many errors are inherent in the measured value. In addition, although the moisture content of the ground material mixed with constituent materials of various particle sizes is affected by fluctuations in the particle size distribution, it is also an error that the RI instrument cannot measure the moisture content of the ground material in consideration of the fluctuations in the particle size distribution. Cause. In order to construct a high-quality civil engineering structure using uneven ground materials, it is desired to develop a technology that can continuously and accurately measure the moisture content of a large amount of ground materials.

  Accordingly, an object of the present invention is to provide a method and system capable of continuously and accurately measuring the amount of water contained in the ground material.

The present inventor has paid attention to near-infrared light (refer to Patent Documents 3 and 4). For example, as shown in FIG. 8, the near-infrared light having a wavelength range of about 0.7 μm to 2.5 μm. When water is irradiated with water, absorption occurs at a predetermined wavelength λi (for example, λ1 = 1.2 μm, λ2 = 1.45 μm, λ3 = 1.94 μm), and the reflected light or transmitted light of the predetermined wavelength λi is the amount of water in the object. Since it attenuates according to (water content ratio), the water content (water content ratio) in the object can be obtained from the reflectance or transmittance Si, specifically, a predetermined wavelength λi as shown in equation (1). A proportional parameter P (coefficients a, b, c, d in the equation (1)) between the reflectance or transmittance Si (hereinafter sometimes simply referred to as reflectance Si) and the amount of water W in the object is previously calibrated. The absorption amount Si of the predetermined wavelength λi to be measured is expressed by equation (1) The amount of moisture is calculated by substitution, or the reflectance or transmittance R (hereinafter also referred to simply as reflectance R) of a specific wavelength (reference wavelength) that is not easily affected by moisture is also obtained (2 ), The proportional parameter P (coefficients a, b, c, d in equation (2)) is calibrated based on the difference between the reflectance Si of the predetermined wavelength λi and the reflectance R of the reference wavelength. , (1) and (2) calculate the amount of moisture from the absorption amounts Si of the three wavelengths λi, but the number of wavelengths λi used for the calculation may be one, two, or four or more. .
W = a · S1 + b · S2 + c · S3 + d …………………………………… (1)
W = a · ln (R / S1) + b · ln (R / S2)
+ C · ln (R / S3) + d (2)

  FIG. 7 shows a moisture measuring device using near infrared rays disclosed in Patent Document 4. The apparatus of the illustrated example includes a light source lamp 41 that irradiates near-infrared light to a target N, a computer 10 that calculates the amount of water W according to formula (1) or formula (2) by inputting reflected light from the target N, and Have The light source lamp 41 in the illustrated example irradiates a measurement target N with near infrared light including a predetermined wavelength λi and a reference wavelength via a lens 42, a filter wheel 43, a plane mirror 45, and a lens 46. The reflected light from the object N is guided to the light receiving element 50 through the concave mirror 47, the convex mirror 48, and the infrared transmission filter 49, and the predetermined wavelength λi and the reference wavelength in the light receiving element 50 are electrical signals (predetermined wavelengths) corresponding to the reflected light amount. λi and reference wavelength reflectivity) Si, R. The converted electrical signals Si and R are input to the computer 10 via the amplifier 51, the sample hold circuit 52, and the AD converter 53. In the computer 10, the moisture amount W is calculated by substituting the input signals Si and R into the equation (1) or (2), and correction operations such as temperature and humidity are performed as necessary.

  For example, if the moisture measuring device shown in Fig. 7 is installed in the ground material conveyance path (conveyor belt, etc.) at the construction site, it is expected to continuously measure the moisture content of a large amount of ground material that is sequentially conveyed at the construction site. it can. However, according to the preliminary experiment by the present inventor, the near-infrared reflectance is affected by fluctuations in the particle size distribution of the ground material, so the water content W of the ground material is calculated by the equation (1) or (2). Then, there is a problem that the error becomes large. That is, the ground material used in construction works such as dams, seawalls (embankments), embankments, etc. has a particle size range in which the maximum particle size (for example, about 150 mm) can reach 2000 times the minimum particle size (for example, about 0.075 mm). It is wide, and the water content of the maximum particle size and the water content of the minimum particle size are calculated by the same proportional parameter P (coefficients a, b, c, d in the equation (1) or (2)) Have difficulty. In order to measure the moisture content of the ground material having such a wide particle size range by the near infrared reflectance, it is necessary to adjust the proportional parameter P in consideration of the variation of the particle size distribution. The present invention has been completed as a result of research and development based on this idea.

  Referring to the block diagram of FIG. 1 and the flowchart of FIG. 2, the ground material moisture content measuring method according to the present invention includes a sample T of a ground material N in which various particle sizes are mixed in a plurality of configurations according to predetermined particle size ranges. A proportional parameter between the reflectance or transmittance Si of a predetermined wavelength λi and the moisture content Wi of the constituent material Ti when the constituent materials Ti are divided into materials T1, T2,. Pi (for example, proportional parameters ai, bi, ci, di shown in FIG. 6) is detected, and the proportional parameter Pi is weighted (Ii) according to the particle size range for each constituent material Ti (for example, in FIG. 6). When the composite parameters Σ (Ii · ai), Σ (Ii · bi), Σ (Ii · ci), and Σ (Ii · di)) shown are created and the ground material N to be measured is irradiated with near infrared light And a reflectance or transmittance Si of a predetermined wavelength λi In which from the Rameta Q formed by calculating the water content W of the ground material N.

  Further, referring to the block diagram of FIG. 1, the water content measurement system for ground material according to the present invention irradiates near-infrared light to the ground material N in which various particle sizes are mixed, or the reflectance of a predetermined wavelength λi or A light quantity measuring device 34 for measuring transmittance Si, a predetermined wavelength when each of a plurality of constituent materials T1, T2,... Tn obtained by dividing a sample T of the ground material N by a predetermined particle size range is irradiated with near infrared light. The proportional parameter Pi (for example, the proportional parameters ai, bi, ci, di shown in FIG. 6) between the reflectance or transmittance Si of λi and the moisture content Wi of the constituent material Ti is detected, and the proportional parameter Pi is detected as the constituent material Ti. A composite parameter Q created by weighting (Ii) according to each particle size range (for example, composite parameters Σ (Ii · ai), Σ (Ii · bi), Σ (Ii · ci), Σ ( Ii ・ di)) 16 and calculating means 22 for calculating the water content W of the ground material N from the reflectance or transmittance Si of the predetermined wavelength λi and the synthetic parameter Q when the near-infrared light is irradiated to the ground material N to be measured. It is prepared.

  Preferably, the composite parameter Q is proportional to each constituent material Ti by the weight ratio, volume ratio, surface area ratio, average particle diameter of each constituent material Ti, the product of any one of them and the water absorption rate of the constituent material, or the reciprocal thereof. It is assumed that the parameter Pi is created by weighting. In a preferred embodiment, as shown in FIGS. 3 and 4, a light quantity measuring device 34 is provided at a specific portion on the belt conveyor 7 that continuously conveys the ground material N, and is calculated by the calculation means 22 when irradiated with near infrared light. Smoothing means 23 for obtaining the moisture content W of the ground material N as an average value (= ΣW / E) of the moisture content W continuously calculated for a predetermined time E is provided (see FIG. 1). In a further preferred embodiment, as shown in FIG. 4, the management reference value C of the moisture content W of the ground material N is stored in the storage means 16, and the calculated value W of the moisture content of the ground material or an average value thereof for a predetermined time E is stored. (= ΣW / E) is compared with the management reference value C, and determination means 24 for determining the suitability of the water content W of the ground material N is provided.

  The ground material moisture content measuring method and system according to the present invention irradiates near infrared light to each of a plurality of constituent materials T1, T2,. The proportional parameter Pi between the reflectance or transmittance Si of the predetermined wavelength λi and the moisture content Wi of the constituent material Ti is detected, and a weighting Ii corresponding to the particle size range for each constituent material Ti is detected with respect to the proportional parameter Pi. A composite parameter Q is created by applying the reflectance or transmittance Si at a predetermined wavelength λi when the ground material N to be measured is irradiated with near-infrared light, and the water content W of the ground material N from the composite parameter Q. The following advantageous effects are obtained.

(B) By using the synthetic parameter Q obtained by weighting the proportional parameter Pi for each predetermined particle size range of the near infrared ray according to the particle size range, the water content W of the ground material N having a wide particle size range can be accurately measured by the near infrared ray. It can be calculated well.
(B) For example, by applying the present invention to the conveyance path of the ground material N, the water content W of the ground material N having a variation sequentially supplied to the construction site can be continuously and accurately measured.
(C) By continuously measuring the water content W of the ground material N that is sequentially supplied and comparing it with the control reference value C, the contamination of the ground material N that does not satisfy the required quality is monitored, and the existing technology grasps it. It is possible to reduce the quality defect of the structure that was difficult to do.
(D) In addition, by continuously measuring the moisture content W of the ground material N, it is possible to quickly grasp the fluctuation tendency of the moisture content W and take measures such as adjusting the moisture content W at an early stage. The stability of the quality of civil engineering structures can be dramatically improved.
(E) Furthermore, by continuously measuring the water content W of the ground material N, the frequency of quality control tests essential in construction using the ground material N can be rationally reduced, or in response to the occurrence of abnormal values. The frequency of quality control tests can be increased reasonably.

Hereinafter, embodiments and examples for carrying out the present invention will be described with reference to the accompanying drawings.
It is a block diagram of one Example of the moisture content measuring system of this invention. It is an example of the flowchart of the moisture content measuring method of this invention. It is explanatory drawing of the other Example of the moisture content measuring system of this invention. It is explanatory drawing which shows the effect | action of the smoothing means of FIG. It is an example of the graph which shows the correlation with the moisture content measured value using the moisture content measuring method of this invention, and the measured value by the conventional water content ratio test method. It is explanatory drawing of an example of the preparation method of the synthetic | combination parameter by this invention. It is explanatory drawing of the moisture measuring apparatus using the conventional near infrared rays. It is explanatory drawing which shows the principle of the water | moisture content measurement using near infrared rays.

  FIG. 1 shows a block diagram of a moisture content measuring system of the present invention. The system in the illustrated example irradiates near-infrared light to the ground material N (or its sample T) and has three predetermined wavelengths λ (for example, λ1 = 1.2 μm, λ2 = 1.45 μm, λ3 = 1.94 μm). A light quantity measuring device 34 for measuring the reflectance Si, R of the wavelength and the reference wavelength, and a computer 10 for calculating the moisture content W of the ground material N by inputting the reflectance Si, R. For example, as shown in FIG. 3, at a construction site where a structural material (CSG, cement-modified soil, concrete, etc.) is produced using a rock material or other ground material N procured or generated near the site as a raw material, a dump truck, etc. The light quantity measuring device 34 is installed on the transport path (for example, the belt conveyor 7) of the ground material N that is procured by the transporting machine 3 from the place where it is procured or sequentially generated to the construction site, and the reflectance Si measured by the light quantity measuring device 34, R is input to the computer 10 and the moisture content W of the ground material N is continuously measured. However, the application object of the present invention is not limited to the crushed material, but can be widely applied to sand materials, gravel materials and other ground materials N for which measurement of water content is required.

  The light quantity measuring device 34 in the illustrated example can have the same configuration as that of the conventional moisture measuring device described above with reference to FIG. 7. For example, near-infrared light having a wavelength range of about 0.7 μm to 2.5 μm can be obtained. A light source lamp for output, an optical system for guiding the output light to the ground material N (or its sample T), and a light quantity of a predetermined wavelength λi (and a reference wavelength) in the reflected light from the ground material N as an electrical signal (reflectivity) ) Equipped with a light receiving element for converting to Si, R and an optical system for guiding the reflected light from the ground material N to the light receiving element, and outputting the converted electric signals Si, R to the computer 10 via an AD converter It is. The illustrated apparatus uses a light source lamp that emits visible light, and a filter wheel 43 that transmits near-infrared light having a predetermined wavelength λi (and a reference wavelength) is provided between the light source lamp and the ground material N. . However, the light quantity measuring device 34 used in the present invention is not limited to the example of FIG. 7, and is another device that measures the reflectance Si, R of the predetermined wavelength λi (and the reference wavelength) using near infrared light. Is also possible.

  The computer 10 in the illustrated example includes an input device 11 such as a keyboard, an output device 12 such as a display, and storage means 16 such as a primary or secondary storage device. The storage device 16 stores a later-described synthesis parameter Q and the like necessary for calculating the moisture content W of the ground material N. As a built-in program, the moisture content W of the ground material N is calculated from the input means 14 for inputting the reflectance Si, R and other data of the predetermined wavelength λi from the light quantity measuring device 34 and the reflectance Si, R and the composite parameter Q. Calculation means 22 for calculating and output means 15 for outputting the calculated water content W and the like to the output device 12 are provided. The computer 10 in the illustrated example has a creation means 21 for creating the synthesis parameter Q as a built-in program. However, the present invention only requires that the synthesis parameter Q is stored in the storage means 16, and the synthesis parameter creation means. 21 is not essential to the present invention. In addition, the moisture content measurement system of the illustrated example has a separation device 31, a weight measuring device 32, and a water content ratio testing device 33 that are necessary for creating the synthesis parameter Q, but the synthesis parameter Q is stored in the storage means 16. If stored in advance, these devices can be omitted.

  FIG. 2 shows a flowchart of a method for measuring the water content W of the ground material N using the system of FIG. The system of FIG. 1 will be described below with reference to the flowchart of FIG. Steps S101 to S104 in FIG. 2 are used to calculate the water content W of the ground material N from the reflectance Si, R of the ground material N having a wide particle size range at a predetermined wavelength λi by the composite parameter creating means 21 of the computer 10. The initial process for creating the composite parameter Q is shown. First, in step S101, a sample T of the ground material N is used, and the sample T is divided into a plurality of constituent materials T1, T2,. For example, the separation device 31 is a sieving device, and the sample T is divided into five constituent materials T1 to T5 having a particle size of 0 to 5 mm, 5 to 10 mm, 10 to 20 mm, 20 to 40 mm, and 40 to 80 mm. The particle diameter range of the material Ti can be arbitrarily set within a range in which the same proportional parameter P described later can be applied. When the ground material N (or the sample T thereof) includes a constituent material of 80 mm or more, it may be divided into six constituent materials T1 to T6 including a constituent material T6 of 80 to 150 mm.

  In step S102, the moisture content Wi of each constituent material Ti is measured by the water content ratio testing device 33, and the weight ratio (ratio (%) to the total weight of the sample T) of each constituent material Ti is measured by the weight measuring device 32. The water content ratio testing device 33 can determine the moisture content Wi of each constituent material Ti from the mass lost when drying using the above-described constant temperature drying oven, microwave oven, or frying pan. In step S103, the light quantity measuring device 34 irradiates each constituent material Ti with near-infrared light to measure the reflectance Si, R of the predetermined wavelength λi, and the reflectance Si, R and the water content W are described above. Thus, the proportional parameter Pi (coefficients a, b, c, d in the formula (1) or (2)) of each constituent material Ti is detected by calibration so that the formula (1) or (2) is satisfied. . FIG. 6 shows that the coefficients ai, bi, ci, di satisfying the equation (1) or (2) can be detected as the proportional parameter Pi for each of the constituent materials T1, T2,. Yes. The proportional parameter Pi of each constituent material Ti detected in step S103 is stored in the storage means 16.

  Next, in step S104, weighting Ii corresponding to the particle size range for each constituent material Ti is applied to the proportional parameter Pi of each constituent material Ti, so that the composite parameter Q applicable to the ground material N having a wide particle size range is obtained. Create For example, as shown in FIG. 6, the weight ratio of each constituent material Ti measured in step S102 is set as a weight Ii, and proportional parameters Pi of the constituent materials Ti (coefficients ai, bi, ci, di) is multiplied by weighting Ii, and then synthesized to obtain a synthesis parameter Q (= Σ (Ii · ai), Σ (Ii · bi), Σ (Ii · ci), Σ (Ii · di)) Create Table 1 shows that the sample T of the ground material N is divided into five constituent materials T1 to T5 having a particle size of 0 to 5 mm, 5 to 10 mm, 10 to 20 mm, 20 to 40 mm, and 40 to 80 mm. An example of the composite parameter Q created by detecting the proportional parameter Pi and the weight ratio (weighting) Ii and multiplying the proportional parameter Pi of each constituent material Ti by the weight ratio Ii in the same manner as in FIG.

  In step S104, the weight ratio of each constituent material Ti is used as a weighting Ii to create a synthesis parameter Q from each proportional parameter 1 Meta Pi, thereby using a conventional constant temperature drying oven, a microwave oven, or a frying pan as described later. It is possible to calculate the water content W highly correlated with the water content ratio test (see FIG. 5). It is also effective to multiply the proportional parameter Pi of each constituent material Ti by an appropriate correction factor together with the weight ratio Ii so that the moisture content W highly correlated with the water content ratio test can be obtained by the synthesis parameter Q. Table 1 The composite parameter Q is created by multiplying such a correction coefficient. However, the weighting Ii corresponding to the particle size range for each constituent material Ti is not limited to the mass ratio, and for example, the volume ratio and the surface area ratio of each constituent material Ti are obtained so that the water content W highly correlated with the water content ratio test can be obtained. , Average particle size, or their reciprocal. The synthesis parameter Q created in step S104 is stored in the storage means 16 and used in the calculation of the moisture amount (step S106) described later.

  In step S104, it is also effective to reflect the water absorption rate of each constituent material Ti together with the weight ratio, volume ratio, surface area ratio, and average particle diameter of each constituent material Ti in the weighting Ii of each constituent material Ti. It is generally known that each component Ti of the ground coordinate N has a smaller density as the water absorption rate increases, and that the water absorption rate is closely related to the internal void volume (water retention capacity). Yes. Therefore, for example, by setting the product (weight ratio × water absorption) of the weight ratio (or volume ratio, surface area ratio, average particle diameter) of each constituent material Ti and the water absorption rate to weight Ii, The proportional parameter Pi of each constituent material Ti can be synthesized according to the void amount (water retention capacity). In this case, for example, in step S102, the weight ratio (or volume ratio, surface area ratio, average particle diameter) of each constituent material Ti is measured, and the water absorption rate of each constituent material Ti is measured by a conventional method (Non-Patent Document 5). And 6).

  In addition, since the coarse-grained material used for construction work such as dams and seawalls is generally a high-quality (low water absorption) material that satisfies the required quality, the relative water absorption rate is It is known that the constituent material T1 having a particle diameter of 0 to 5 mm is very large, and the constituent materials T2 to T5 having a particle diameter of 5 mm or more are extremely small. Therefore, for example, only the proportional parameter Pi of the constituent material T1 having a particle diameter of 0 to 5 mm is weighted by the weight ratio × water absorption, and the proportional parameters Pi of the other constituent materials T2 to T5 are weighted by the weight ratio and synthesized. Thus, it is also effective to create a composite parameter Q that reflects the contribution of the water retention capacity of the constituent material T1 having a particle diameter of 0 to 5 mm to the total water retention amount of the ground material N. Furthermore, the reciprocal of the product of the weight ratio (or volume ratio, surface area ratio, average particle diameter) of each constituent material Ti and the water absorption (weight ratio × reciprocal of water absorption) may be considered as the weight Ii.

  It should be noted that the process of creating the composite parameter Q in steps S101 to S104 is not necessarily performed at the construction site. For example, the composite parameter Q is created in advance using a sample T of the ground material N in a laboratory or the like, and the composite parameter Q is generated on the site computer. It is also possible to input to 10 and store in the storage means 16. In this case, it suffices to provide a step for inputting the relational expression K to the computer 10 instead of steps S101 to S104, and steps S101 to S104 for creating the synthesis parameter Q from the sample T of the ground material N can be omitted.

  Steps S <b> 105 to S <b> 106 in FIG. 2 indicate processing for calculating the moisture content W of the ground material N to be measured based on the synthesis parameter Q stored in the storage unit 16. First, in step S105, the light quantity measuring device 34 irradiates near-infrared light to the ground material N to be measured to measure the reflectances Si and R of the predetermined wavelength λi, and in step S106, the calculation means 22 of the computer 10 calculates the reflectance. The water content W of the ground material N is calculated from the reflectance Si, R and the composite parameter Q. The graph of FIG. 5 shows the moisture content W calculated from the reflectance Si, R of the ground material N at a predetermined wavelength λi by the synthesis parameter Q in Table 1 and the water content ratio using a conventional constant temperature drying oven, microwave oven, or pan. The experimental result which compared the moisture content of the ground material N calculated | required by the test is shown. The experimental results in FIG. 5 show that the water content W calculated by the synthesis parameter Q has a high correlation (correlation coefficient = correlation of about 0.992) with the water content obtained by the conventional water content ratio test method. This shows that the moisture content W of the ground material N having a wide particle size range can be accurately measured by near infrared rays by using the synthetic parameter Q described above.

  Further, as shown in FIG. 3, the light quantity measuring device 34 is installed at a specific portion of the ground material N on the conveyor belt conveyor 7 and the measured value (reflectance Si, R) of the light quantity measuring device 34 is calculated by the computer 10. By repeating step S105 input to the means 22 and step S106 of calculating the moisture content W using the synthesis parameter Q, the moisture content W of the ground material N having variations can be measured continuously and accurately. The continuous measurement graph of FIG. 4 shows an example of the moisture content W of the ground material N that is continuously measured by repeating the cycle of steps S105 to S106.

  In steps S110 to S111 in FIG. 2, the moisture content W of the ground material N continuously calculated by the calculation means 22 is input to the determination means 24 of the computer 10, and the determination means 24 determines the moisture content W of the ground material N. The process which determines the propriety (the quality of the ground material N) of the water content W compared with the management reference value C is shown. As such a control standard value C, for example, a plurality of structural materials are manufactured using ground materials N having different moisture contents W, and the strength (for example, uniaxial compressive strength) of each structural material is tested to satisfy the required strength. The upper limit value (or lower limit value) of the moisture amount W to be obtained can be obtained in advance, and the upper limit value (or lower limit value) of the moisture amount obtained in the test can be registered in the storage means 16 in step S101, for example. The management reference value C can be set based not only on the strength but also on the density of the structural material, workability (trafficability, etc.), and the like.

  When the water content W of the ground material N deviates from the management reference value C in step S111, for example, after the water content W of the ground material N is adjusted in step S112, the process returns to step S105, and the above-described steps S105 to S111 are repeated. Thus, the moisture content W of the ground material N can be re-determined. In this way, by continuously measuring the moisture content W of the ground material N and comparing it with the control reference value C, contamination of the ground material N that does not satisfy the required quality can be prevented, and even the conventional moisture content test method can grasp it. It is possible to greatly reduce the quality defects of the structural materials that were not present, and to improve the quality stability of civil engineering structures.

  In the embodiment of FIG. 3, the water content of the ground material N in the belt conveyor 7 at the front stage of the mixer for manufacturing the structural material (CSG, cement improved soil, concrete, etc.) by adding water and cement (solidifying material) to the ground material N. 2 is measured along the flowchart of FIG. 2, and the moisture content W of the structural material including the ground material N is measured along the flowchart of FIG. The amount of moisture W of the ground material N measured in the previous stage of the mixer is registered in the storage means 16 of the computer 10 as a management reference value C, such that the amount of moisture W that the structural material manufactured by the mixer 8 satisfies the required quality (for example, strength). A structural material that satisfies the required quality is manufactured by adjusting the amount of water and cement charged into the mixer 8 based on the difference between W and the control reference value C. Further, the moisture content W of the structural material measured in the previous stage of the mixer is compared with the management reference value C, and it is confirmed in step S111 that the moisture content W of the structural material is within the range of the management reference value C. When the moisture amount W deviates from the control reference value C, the amounts of water and cement charged into the mixer 8 are readjusted in step S112.

  When it is determined in step S111 in FIG. 2 that the water content W of the ground material N is within the range of the management reference value C, the process proceeds to step S113. For example, the water content W measured in step S106 is stored in the storage means of the computer 10. After accumulative storage in step 16, it is determined in step S114 whether or not to continue measuring the moisture content of the ground material N. When continuing, it returns to step S105 and repeats step S105-S112 mentioned above about the ground material N supplied next time. By accumulating the moisture content W of the ground material N continuously measured in step S113 in the storage means 16, the determination means 24 determines the moisture content of the supply material N in the determination process of steps S110 to 112 next time. It is possible to determine the change over time (moving average) of the amount W and quickly grasp the change in the quality of the ground material N.

  Thus, it is possible to provide the “method and system capable of continuously and accurately measuring the amount of water contained in the ground material”, which is an object of the present invention.

  In steps S107 to S109 of FIG. 2, the moisture content W of the ground material N continuously calculated by the calculation means 22 is input to the smoothing means 23 of the computer 10, and the smoothing means 23 averages the predetermined time E. The process for obtaining the water content W of the ground material N as (= ΣW / E) is shown. In the case of the ground material N having a wide particle size range, although there is a difference in degree, it is not possible to avoid variations in the measured value of the water content W depending on the measurement site. By avoiding the influence of variation in measured values. On the other hand, in the present invention using the near infrared ray, the moisture content W (for example, the moisture content W of one grain of the constituent material) of the local part irradiated with the near infrared light is continuously measured. As shown in the continuous measurement graph of FIG. 4, the variation in the measured value of the water content W can be large. In the leveling means 23, the measurement value of the moisture amount W calculated continuously is averaged over a predetermined time E, and the average value (= ΣW / E) is set as the moisture amount W, thereby affecting the variation of the measurement value. Can be avoided.

  In step S107, it is determined whether or not the measured value of the water content W is leveled. When leveling, the measured value of the water content W for a predetermined time E is waited in step S108. When the measured value of the moisture amount W for the predetermined time E has already been calculated, the measured amount of the moisture amount W calculated this time and the moisture amount for the predetermined time E recorded in the storage means 16 in step S109. The measured value of W is input to the leveling means 23, and the moisture content W of the ground material N is calculated as an average value (= ΣW / E) for a predetermined time E. The moving average graph of FIG. 4 shows an example of the water content W of the ground material N calculated in step S109. From the comparison of the two graphs in FIG. 4, it can be seen that the influence of variation in the measured values can be avoided by setting the average value (= ΣW / E) for a predetermined time as the water content W.

The predetermined time E for obtaining the moving average in the leveling means 23 can be registered in advance in the storage means 16 of the computer 10 as the transport time per 1 m ³ of the ground material N by the belt conveyor 7 (see FIG. 3), for example. it can. By using such a conveyance time, the water content W per 1 m ³ of the ground material N can be calculated in step S109. Furthermore, also, in step S109, to 10 m ³ without the ground material N by leveling means 23 calculates the water content W per 100 m ^3, to no water content W and 10 m ³ per 1 m ³ and the water content W per 100 m ³ By simultaneously outputting and displaying both to the output device 12, both the long-term fluctuation tendency and the short-term fluctuation tendency of the moisture content W of the ground material N can be confirmed simultaneously, and the quality of the ground material N can be controlled from both sides. , It is also possible to monitor.

DESCRIPTION OF SYMBOLS 1 ... Sampling place 2 ... Crushing device 3 ... Transport device 5 ... Weight measuring device 6 ... Loading hopper 7 ... Belt conveyor 8 ... Mixer 10 ... Computer 11 ... Input device 12 ... Output device 14 ... Input means 15 ... Output means 16 ... Memory Means 21 ... Synthetic parameter creation means 22 ... Calculation means 23 ... Smoothing means 24 ... Determination means 31 ... Separation device 32 ... Weight measuring device 33 ... Moisture ratio test device 34 ... Light quantity measurement device 41 ... Light source 42 ... Lens 43 ... Filter wheel 44 ... Motor 45 ... Plane mirror 46 ... Lens 47 ... Concave mirror 48 ... Convex mirror 49 ... Infrared transmission filter 50 ... Light receiving element 51 ... Amplifier 52 ... Sample hold circuit 53 ... AD converter N ... Ground material T ... Ground material sample W ... Water content (Water content) I ... Weighting (coefficient)
S, R ... reflectance or transmittance C ... management reference value E ... predetermined time P ... proportional parameter Q ... composite parameter

Claims (8)

A sample of a ground material in which various particle sizes are mixed is divided into a plurality of constituent materials according to a predetermined particle size range, and the reflectance or transmittance of a predetermined wavelength when each of the constituent materials is irradiated with near infrared light Detecting a proportional parameter with the moisture content of the constituent material, creating a composite parameter that weights the proportional parameter according to the particle size range for each constituent material, and irradiating the ground material to be measured with the near infrared light A method for measuring a moisture content of a ground material, which is obtained by calculating a moisture content of the ground material from the reflectance or transmittance at a predetermined wavelength and the synthetic parameter. 2. The measurement method according to claim 1, wherein the synthetic parameter is configured by a weight ratio, a volume ratio, a surface area ratio, an average particle diameter of each of the constituent materials, a product of any one of them and a water absorption rate of the constituent materials, or an inverse number thereof. A method for measuring the moisture content of ground materials, which is created by weighting proportional parameters for each material. 3. The measurement method according to claim 1 or 2, wherein the near-infrared light is irradiated to a specific part on the belt conveyor while the ground material is continuously conveyed by a belt conveyor, and the moisture amount calculated continuously at the time of irradiation. A method for measuring the amount of water in a ground material obtained by obtaining the amount of water in the ground material as an average value for a predetermined time. The measurement method according to any one of claims 1 to 3, wherein a management reference value for the moisture content of the ground material is determined, and a calculated value of the moisture content of the ground material or an average value thereof for a predetermined time is compared with a management reference value. A method for measuring the moisture content of a ground material, which is determined by determining whether the moisture content of the ground material is appropriate. A light quantity measuring device that measures the reflectance or transmittance of a predetermined wavelength by irradiating near-infrared light to a ground material in which various particle sizes are mixed, and a plurality of constituent materials obtained by dividing the ground material sample into predetermined particle size ranges Detecting a proportional parameter between the reflectance or transmittance at a predetermined wavelength when the near infrared light is irradiated to each of the above and the moisture content of the constituent material, and the proportional parameter is determined according to the particle size range for each constituent material. Storage means for storing weighted synthetic parameters, and moisture of the ground material from the reflectance or transmittance of a predetermined wavelength when the ground material to be measured is irradiated with the near infrared light and the synthetic parameters A water content measurement system for a ground material comprising a calculation means for calculating the amount. 6. The measurement system according to claim 5, wherein the composite parameter is configured by a weight ratio, a volume ratio, a surface area ratio, an average particle diameter of each constituent material, a product of any one of them and a water absorption rate of the constituent material, or an inverse number thereof. Moisture content measurement system for ground materials, created by weighting proportional parameters for each material. 7. The measurement system according to claim 5 or 6, wherein the light quantity measuring device is provided at a specific portion on a belt conveyor that continuously conveys the ground material, and is continuously calculated by the calculating means when the near infrared light is irradiated. A water content measurement system for a ground material provided with a smoothing means for determining the water content of the ground material as an average value of a predetermined amount of water content. The measurement system according to any one of claims 5 to 7, wherein a management reference value of the moisture content of the ground material is stored in the storage means, and a calculated value of the moisture content of the soil material or an average value and a management reference value for a predetermined time thereof. And a water content measurement system for the ground material provided with a determination means for determining whether or not the water content of the ground material is appropriate.