JP6086769B2 - Porosity evaluation method, filter basin construction method, filter basin soundness evaluation method - Google Patents

Description

The present invention, void ratio valuation method relates soundness evaluation method of construction methods and filtration ponds filtration pond.

  In the past, treated water that has undergone treatment such as coagulation sedimentation and sand filtration has been chlorinated at water purification plants, but ozone is used to avoid the generation of harmful organochlorine compounds and improve water quality by removing mold odors and pigments. The introduction of advanced treatment, which is the oxidative decomposition treatment of organic matter and the adsorption removal treatment of pollutants by biological activated carbon, is progressing.

  As a typical structural example of a filtration pond represented by a biological activated carbon adsorption pond, a lower water collecting apparatus having a porous concrete layer is installed. The lower water collecting device has a small air outlet for the purpose of supporting filter media using activated carbon, anthracite, etc. arranged in the upper part, equal collection of treated water, and equal dispersion during simultaneous washing with water and air. A porous concrete layer supporting a filter medium is formed on the uppermost layer, which includes air dispersion beams arranged in an array, a slit plate disposed thereon, and a dispersed gravel layer disposed thereon.

  When filtering the inflow water to the filter basin, the filtered treated water passes through the pores of the porous concrete layer of the lower water collecting device and flows out into the lower water collecting basin. The quality of the porous concrete greatly affects the function of the lower water collecting device because the cleaning water and the air discharged from the air dispersion beam are supplied to the filter medium layer from below through the porous concrete layer. Therefore, it is necessary for porous concrete to have both the physical strength that can withstand the filter medium layer and the backwashing pressure, and the equal processing ability and pressure loss performance during filtration and backwashing. It needs to be managed so that a certain porosity falls within a range of 25% to 35%.

  Conventionally, in order to measure the porosity of porous concrete, specimens of the same composition as porous concrete placed on-site are manufactured at the same time, and the Archimedes method is used to correlate the mass of the specimen in air and water. A method of calculating the porosity from the relationship is adopted.

  In addition, in order to confirm the air dispersion status of the porous concrete layer after placing the porous concrete on the site implementation site, the air washing blower is operated from a state where water is stretched on the porous concrete layer at a depth of several centimeters. Thus, a method is employed in which air backwashing is actually performed, and the occurrence of bubbles on the water surface is visually confirmed on the porous concrete layer.

  On the other hand, Patent Document 1 proposes a sound wave type high-performance pavement voidage detection device that measures the internal voidage of a high-performance pavement while traveling at high speed in a non-contact, non-destructive manner. The sound wave type high-performance pavement voidage detection device is configured such that a sound insulation box whose one end is opened toward a road surface is attached to a road surface voidage measurement vehicle, and a speaker and a microphone are arranged in the sound insulation box.

  While driving the road surface porosity measurement car at high speed, emit a pulse sound from the speaker, and the pulse sound emitted from the speaker reaches the microphone before it reaches the road surface, and the pulse sound is reflected by the road surface and reflected on the microphone. The reflected wave that has arrived is detected by a microphone, and the internal porosity of the high-performance pavement is determined based on the ratio of the incident wave and the reflected wave.

JP 2003-83943 A

  However, the measurement method using the Archimedes method can accurately measure the porosity of the specimen, but because the placement range and compaction method are different from the actually placed porous concrete, the measured specimen There is concern that the value is different from the porosity.

  In addition, the method for visually confirming the bubble generation state has problems that the porosity cannot be quantitatively grasped, and the judgment on the bubble generation state may vary depending on the measurer. In addition, if the blower equipment that supplies air to the air dispersion beam and the water supply / drainage equipment of the filter basin are not installed after the construction, the plant equipment necessary for the test is temporarily installed and the test is performed. And had to spend time.

  By the way, the acoustic high-performance pavement porosity detection device described in Patent Document 1 only detects a rough value even if it is said to be the porosity of the road, and makes the automobile run at a speed of 80 Km / h or more. Porosity evaluation that enables efficient and accurate evaluation of the appropriateness of the porosity of the porous concrete layer of the lower water collecting device, such as the problem that subtle changes in the porosity cannot be detected due to the measurement A method was sought.

In view of the above-described problems, an object of the present invention is to provide a porosity evaluation method capable of efficiently and accurately evaluating the appropriateness of the porosity of the porous concrete layer of the lower water collecting apparatus, and to evaluate the porosity the method is in that it provides a sound evaluation methods construction methods and filtration pond applied Carlo over pond.

In order to achieve the above-mentioned object, the first characteristic configuration of the porosity evaluation method according to the present invention is a porous concrete floor portion placed in a filtration pond as described in claim 1 of the claims. A void ratio evaluation method for evaluating the suitability of the void ratio using a predetermined void ratio measuring device, the area dividing step for dividing the porous concrete floor into a predetermined size, and for each divided area A measurement step including an individual measurement step for obtaining an evaluation value by measurement using the porosity measuring device at least in one place, and an evaluation value for each category obtained in the individual measurement step is a predetermined upper limit determination value and a lower limit calculated: a first evaluation step of determining whether there during the determination value, the number of adjacent of the deviation classified as distribution of deviation segment that does not exist between the evaluation value is the upper limit determination value and the lower limit determination value Comprising a second evaluation step, and the first evaluation step, a third evaluation step of the evaluation value calculates the ratio to the total number of sections the number of segments that exist between a predetermined upper threshold value and the lower limit determination value Provided, when the ratio is higher than a predetermined reference ratio and the number of adjacent deviation segments obtained in the second evaluation step is less than the predetermined reference number, the void ratio of the floor portion is evaluated as appropriate. There are four evaluation steps .

  By dividing the floor area of porous concrete into a predetermined size in the area division step and measuring at least one place for each section in the individual measurement step to obtain an evaluation value representative of the section, a certain large area Even if it is a floor part, it becomes possible to measure efficiently.

In the first evaluation step, it is determined whether or not the evaluation value of each section exists between a predetermined upper limit determination value and a lower limit determination value, that is, whether or not the porosity is appropriate for each divided section, In the second evaluation step, it is determined in what distribution state the deviation category whose evaluation value does not exist between the upper limit determination value and the lower limit determination value. The upper limit or lower limit determination value is an evaluation value corresponding to an appropriate upper limit or lower limit of the porosity. Based on these results, that is, based on the distribution of the area where the appropriate evaluation value was obtained and the area where the appropriate evaluation value was not obtained, it was evaluated whether or not the porosity of the floor as a whole was appropriate. The Therefore, even evaluated is a large area, ing as propriety of porosity of the porous concrete layer can be evaluated efficiently and accurately.

Sections commentary value exists between the predetermined upper threshold value and the lower limit determination value can be determined to be a proper division porosity, when the adjacent number of departure segment is small dispersed in the overall deviation divided Can be judged. Therefore, if the existence ratio of the appropriate section is higher than the predetermined reference ratio, and if the number of neighbors of the deviation section is less than the reference number of neighbors, the floor porosity as a whole is appropriate, for example, sufficient Therefore, it can be evaluated that a filtration function can be realized or a sufficient backwash function can be realized.

In the second feature configuration, as described in claim 2 , in addition to the first feature configuration described above, the number of adjacent deviation segments obtained in the second evaluation step is equal to or greater than a predetermined reference number. In this case, a re-measurement step is performed to obtain an evaluation value by measurement using the porosity measurement device at a plurality of positions separated by a predetermined distance from the measurement location measured in the measurement step for each adjacent section, and the re-measurement step When the ratio of the number of measurement positions existing between the upper limit determination value and the lower limit determination value is equal to or greater than a predetermined ratio, the classification exists between the upper limit determination value and the lower limit determination value. Then, it is evaluated and the second evaluation step is executed again.

  When the number of adjacent deviation segments is equal to or greater than the predetermined reference number, it can be determined that there is a high possibility that the porosity is in an inappropriate state in a certain wide area. Therefore, in order to verify whether or not the porosity is actually in an inappropriate state in a wide area, a re-measurement step is executed, and evaluation is performed at a plurality of positions separated by a predetermined distance from the original measurement location for each corresponding category. A value is determined. If the ratio of the number of measurement positions existing between the upper limit determination value and the lower limit determination value is equal to or greater than a predetermined ratio, the classification is re-evaluated as an appropriate void ratio as a whole. Based on the result of the re-evaluation, the second evaluation step is executed again, and a final overall evaluation with high reliability can be obtained.

The third feature structure, as described in the claim 3, in addition to the first or second characteristic feature of the above, porosity for a plurality of porous concrete floor sample of different values in a known A reference evaluation value calculating step for obtaining an evaluation value by measurement using the porosity measuring device, and a floor sample indicating a porosity in the upper limit of the predetermined allowable range or in the vicinity of the upper limit among the plurality of floor samples And setting an evaluation value that is an upper predetermined ratio from the relative frequency distribution of the evaluation values obtained in the reference evaluation value calculation step as the upper limit determination value, and a lower limit of a predetermined allowable range among the plurality of floor samples or A criterion value for setting an evaluation value that is a lower predetermined ratio from the relative frequency distribution of the evaluation values obtained in the reference evaluation value calculation step as the lower limit determination value for a floor sample having a porosity near the lower limit In that it comprise a constant step.

  The upper limit determination value and the lower limit determination value described above are calculated through a reference evaluation value calculation step and a determination reference value setting step. In the reference evaluation value calculation step, a plurality of evaluation values are obtained by measurement using a porosity measuring device for a plurality of floor samples made of porous concrete having different porosity values and different values. The distribution of evaluation values for each floor sample is almost normal. Next, in the determination reference value setting step, an evaluation value that becomes an upper predetermined ratio from the relative frequency distribution of the obtained evaluation values for the floor sample indicating the upper limit of the allowable range or the porosity in the vicinity of the upper limit is an upper limit determination value. For the floor sample showing the lower limit of the allowable range or the porosity in the vicinity of the lower limit, an evaluation value that becomes a lower predetermined ratio from the relative frequency distribution of the obtained evaluation values is set as the lower limit determination value. The upper predetermined ratio and the lower predetermined ratio are safety factors set so that noise mixed in the evaluation value is not adopted as the determination value.

As described in claim 4, the fourth characteristic configuration is a porosity for evaluating the suitability of the porosity of a porous concrete floor placed in a filtration pond using a predetermined porosity measuring device. An evaluation method comprising an area dividing step of dividing the porous concrete floor portion into a predetermined size, and obtaining an evaluation value by measurement using the porosity measuring device at least at one location for each of the divided areas A measurement step including a measurement step, a first evaluation step for determining whether or not an evaluation value for each category obtained in the individual measurement step exists between a predetermined upper limit determination value and a lower limit determination value, and evaluation A second evaluation step for obtaining the number of neighbors of the departure section as a distribution state of the departure section whose value does not exist between the upper limit determination value and the lower limit determination value, and the departure section obtained in the second evaluation step When the adjacent number is equal to or greater than a predetermined reference adjacent number, an evaluation value is obtained by measurement using the porosity measuring device at a plurality of positions separated by a predetermined distance from the measurement location measured in the measurement step for each adjacent section. When the re-measurement step is executed and the ratio of the number of measurement positions where the evaluation value obtained in the re-measurement step is between the upper limit determination value and the lower limit determination value is equal to or greater than a predetermined ratio, the classification is the upper limit The second evaluation step is performed again by evaluating that it exists between the determination value and the lower limit determination value.

When the number of adjacent deviation segments is equal to or greater than the predetermined reference number, it can be determined that there is a high possibility that the porosity is in an inappropriate state in a certain wide area. Therefore, in order to verify whether or not the porosity is actually in an inappropriate state in a wide area, a re-measurement step is executed, and evaluation is performed at a plurality of positions separated by a predetermined distance from the original measurement location for each corresponding category. A value is determined. If the ratio of the number of measurement positions existing between the upper limit determination value and the lower limit determination value is equal to or greater than a predetermined ratio, the classification is re-evaluated as an appropriate void ratio as a whole. Based on the result of the re-evaluation, the second evaluation step is executed again, and a final overall evaluation with high reliability can be obtained.

As described in the fifth aspect, the fifth characteristic configuration is a porosity that evaluates the suitability of the porosity of a porous concrete floor placed in a filtration pond using a predetermined porosity measuring device. An evaluation method comprising an area dividing step of dividing the porous concrete floor portion into a predetermined size, and obtaining an evaluation value by measurement using the porosity measuring device at least at one location for each of the divided areas A measurement step including a measurement step, a first evaluation step for determining whether or not an evaluation value for each category obtained in the individual measurement step exists between a predetermined upper limit determination value and a lower limit determination value, and evaluation A second evaluation step for obtaining the number of adjacent departure sections as a distribution state of the departure section whose value does not exist between the upper limit determination value and the lower limit determination value; and a plurality of porous concretes having different porosity values A reference evaluation value calculation step for obtaining an evaluation value by measurement using the porosity measuring device for a floor sample made of a product, and an upper limit of a predetermined allowable range of the plurality of floor samples or a porosity near the upper limit With respect to the floor sample shown, the upper limit determination value is set as the upper limit determination value from the relative frequency distribution of the evaluation values obtained in the reference evaluation value calculation step, and among the plurality of floor samples For a floor sample having a porosity near the lower limit or near the lower limit of the predetermined allowable range, an evaluation value that is a lower predetermined ratio from the relative frequency distribution of the evaluation values obtained in the reference evaluation value calculating step is the lower limit determination value. And a determination reference value setting step to be set.

The upper limit determination value and the lower limit determination value described above are calculated through a reference evaluation value calculation step and a determination reference value setting step. In the reference evaluation value calculation step, a plurality of evaluation values are obtained by measurement using a porosity measuring device for a plurality of floor samples made of porous concrete having different porosity values and different values. The distribution of evaluation values for each floor sample is almost normal. Next, in the determination reference value setting step, an evaluation value that becomes an upper predetermined ratio from the relative frequency distribution of the obtained evaluation values for the floor sample indicating the upper limit of the allowable range or the porosity in the vicinity of the upper limit is an upper limit determination value. For the floor sample showing the lower limit of the allowable range or the porosity in the vicinity of the lower limit, an evaluation value that becomes a lower predetermined ratio from the relative frequency distribution of the obtained evaluation values is set as the lower limit determination value. The upper predetermined ratio and the lower predetermined ratio are safety factors set so that noise mixed in the evaluation value is not adopted as the determination value.

The sixth characterizing feature of the can, as noted in the claim 6, in addition to the third or fifth characterizing feature described above, the upper predetermined ratio and range of lower predetermined ratio 5-20% of the rejection region It is in the point set to.

The statistical method is often critical region 5% is selected as a safety factor, but in order to enhance the safety factor in the present invention, it is configured as a preferred range in the range of 5-20% of the critical region.

The characteristic configuration of the construction method of the filter basin according to the present invention is that, as described in claim 7 , the treated water permeates downward through the porous concrete floor placed in the filter basin, and the cleaning air is upward. A construction method of a filtration pond configured to permeate to the porous concrete floor portion placed in the filtration basin, comprising any one of the first to sixth characteristic configurations When the porosity evaluation method is executed and the porosity is evaluated as appropriate, the upper part of the floor portion is filled with a filter medium. When the porosity evaluation method is evaluated as negative, the porous concrete is reconstructed. It is in the point to take measures such as.

  If the porosity is evaluated as negative by the porosity evaluation method, the floor does not function properly as a whole, that is, it is evaluated that the filtration performance is inappropriate. In order to achieve this, measures such as re-construction of the cast porous concrete are taken.

The characteristic configuration of the filter basin soundness evaluation method according to the present invention is that, as described in claim 8 , the treated water permeates downward through a porous concrete floor placed in the filter basin. A method for evaluating the integrity of a filtration pond configured to allow air to permeate upward , comprising any one of first to sixth characteristic configurations with respect to the porous concrete layer placed in the filtration pond It is in the point which evaluates the soundness degree of the said filtration basin by performing the porosity evaluation method which compared the measured evaluation value before use, and the evaluation value after use.

  When used for a long period of time, the pores of the porous concrete that forms the floor of the filtration basin are gradually clogged, so the function can be restored by, for example, regular backwashing. There is a risk of disappearing. Even in such a case, by comparing the evaluation value before use measured by the porosity evaluation method with the evaluation value after use, the soundness of the filtration pond can be appropriately evaluated.

As described above, according to the present invention, while providing a porosity evaluation method capable of efficiently and accurately evaluating the appropriateness of the porosity of the porous concrete layer of the lower water collecting apparatus, the porosity evaluation method It applied Carlo soundness evaluation method of construction methods and filtration pond over pond can now be provided.

Explanatory drawing of the lower water collection device provided in the filtration pond (A) is explanatory drawing of a filtration process, (b) is explanatory drawing of a washing | cleaning process. (A) is a plan view of the porosity measuring device, (b) is the front view, (c) is the back view, and (d) is the side view. (A) is a block diagram of the wall part of the porosity measuring device, (b) is an explanatory diagram of the measurement principle of the porosity measuring device (A) is a characteristic diagram of the porosity with the gap length L of the boundary wall as a parameter and the measured sound volume in the second sound insulation chamber, and (b) is a porous concrete layer in the frequency band of the sound source from 5 k to 8 kHz. Figure of porosity characteristics (A) is explanatory drawing of the porous concrete layer divided into the predetermined size, (b) is explanatory drawing of the measurement position at the time of re-measurement in the division (A) is a chart of volume reduction and judgment result for each category, (b) is a volume reduction distribution characteristic diagram showing the measurement result. Flow chart showing the evaluation procedure for porosity of porous concrete layer (A) is explanatory drawing of the upper limit and lower limit threshold value for evaluating the porosity of a porous concrete layer, (b) is setting explanatory drawing of a lower limit threshold value, (c) is setting explanatory drawing of an upper limit threshold value

  Hereinafter, while explaining the filtration pond and the porosity measuring device to which the porosity evaluation method according to the present invention is applied, the porosity evaluation method is described in detail, and the filtration pond construction method and the filtration pond soundness evaluation method are also described. Will be explained.

  FIG. 1 shows a lower water collecting apparatus 1 installed in the filtration basin A. In the lower water collecting apparatus 1, a plurality of air dispersion beams 2 in which minute air outlets 2a are arrayed are arranged in parallel in the short direction of the rectangular bottom at the rectangular bottom of each of the plurality of concrete treatment tanks installed adjacent to each other. Slit plates 3 arranged in a posture and having a SUS net 3a formed on the adjacent air dispersion beams 2 are arranged. An air bottle 7 is formed at one end of the air dispersion beam 2, and air can be ejected from the air outlet 2 a formed in each air dispersion beam 2 from the air bottle 7.

  Further, a dispersed gravel layer 4 in which dispersed gravel is spread is formed on the upper portion of the slit plate 3, and a porous concrete layer 5 which is a porous body is formed on the upper portion thereof. The upper part of the porous concrete layer 5 is filled with a filter medium 6 such as activated carbon or anthracite, and treated water Wt is supplied from above.

  FIG. 2A shows a cross-sectional view of the lower water collecting apparatus 1 in the filtration process. Inflow water to the filtration basin A flows into the drainage basin 10 from the inflow basin 8 through the inflow gate G1, and flows into the lower water collecting apparatuses 1 via the troughs 11 provided in the drainage basin 10.

  The treated water is subjected to the adsorption treatment of the pollutant in the packed layer of the filter medium 6 of the lower water collecting apparatus 1, and further flows out downward from the pores formed in the porous concrete layer 5, via the flow meter Q and the flow control valve V1. It is taken out as filtered water. In the figure, B is a blower, and M is an opening / closing drive for the inflow gate G1 and the drain gate G2.

  FIG. 2B shows a cross-sectional view of the lower water collecting apparatus 1 in the cleaning process. If a certain amount of pollutant accumulates in the packed bed of the filter medium 6 by continuing the filtration process, the filtration performance is lowered. Therefore, a cleaning process for cleaning the filter medium 6 and removing the pollutant is performed.

  First, the inflow gate G1 is closed from the filtration step of FIG. 2 (a), the filtered water is drained from the lower water collecting apparatus 1, and the drainage gate G2 is opened to drain the treated water from the drainage basin 10. The process is executed.

  Thereafter, the flow regulating valve V1 is closed and the backwash valve V2 is opened, and the washing water is injected from the lower surface of the porous concrete layer 5 to the packed layer of the filter medium 6, and the blower B is activated to air from the air tank 7 Air is injected into the dispersion beam 2, and air is ejected from each air outlet 2 a formed in the air dispersion beam 2.

  The water level gradually rises by pouring the washing water, and at this time, the granular filter medium 6 is vigorously stirred by water and air, and the pollutant is separated from the filter medium 6 and floats on the washing water.

  Immediately before the water level reaches the trough 11, the blower B is stopped, and the pollutant floating in the washing water flows out from the trough 11 to the drainage basin 10 together with the washing water, and is drained from the drain gate G2.

  As described above, the porous concrete layer 5 needs to pass filtered water from the upper side to the lower side in the filtration step, and it is necessary to pass the cleaning water from the lower side to the upper side in the cleaning step. Therefore, the porosity needs to be adjusted to a range of 25 to 35%.

  Such a porous concrete layer 5 is constructed by being placed on a dispersed gravel layer 4 with a thickness of 70 mm and compacted. Although the pond size differs depending on the water purification plant, the placement area is generally When the length is about 10-15m, the width is about 3-5m, and the area is very wide, and even if the void ratio deviates from the range of 25-35% even in a part of the area, appropriate filtration process and washing process in that area Cannot be done.

  The porosity measuring device according to the present invention is a portable device that measures the porosity of a porous body based on acoustic characteristics. For example, the porosity of the porous concrete layer 5 described above is measured during construction or maintenance, It is an apparatus used for evaluating whether or not the porosity is within an appropriate range.

FIGS. 3A to 3D show an overview of an example of the porosity measuring device 20.
In the porosity measuring device 20, a first sound insulation chamber 21 and a second sound insulation chamber 22 having openings 24 and 25 formed on one end side so as to face the porous body 5 are disposed adjacent to each other via a central boundary wall 23. A sound source 30 made of a speaker is installed in the first sound insulation chamber 21, and a first acoustic sensor 32 made of a microphone that measures the sound intensity of the direct sound output from the sound source 30 is installed, and a sound source is installed in the second sound insulation chamber 22. The second sound composed of a microphone that measures the acoustic intensity directly output from the gap portion 26 of a predetermined size that is output from 30 and formed between the boundary wall 23 and the porous body 5 and the reflected acoustic intensity from the porous body 5. A sensor 34 is installed. The sound source 30 is an air vibration source of the present invention.

  As shown in FIG. 4A, the wall portion and the boundary wall 23 forming the first sound insulation chamber 21 and the second sound insulation chamber 22 are both polyvinyl chloride sheets on both sides of a thick plate-like sound absorbing member. It is made of a plate material with a thickness of about 35 mm and is insulated so that noise from the outside does not enter the first sound insulation chamber 21 and the second sound insulation chamber 22, and the sound output from the sound source 30 is not absorbed. It is configured to be reflected by a sheet made of polyvinyl chloride.

  The first sound insulation chamber 21 and the second sound insulation chamber 22 are configured by a rectangular parallelepiped having a width of 200 mm, a height of 360 mm, and a depth of 230 mm, and the length L of the gap between the surface position of the openings 24 and 25 and the lower end of the boundary wall 23. Is set in a range of 15 to 30 mm.

  A gap adjusting mechanism 40 that adjusts the gap width L of the gap formed between the boundary wall 23 and the porous body 5, that is, the gap between the surface position of the openings 24 and 25 and the lower end of the boundary wall 23 is a boundary. It is provided on the wall 23. The gap adjusting mechanism 40 is configured by a gap adjusting member having a U-shaped cross section that is bolt-fixed at the lower end portion of the boundary wall 23 so as to be vertically adjustable.

  In order to evaluate whether or not the porosity of the porous body 5 is within the allowable range, the sound intensity of the reflected sound is appropriate within the allowable range of the porosity, in this embodiment, inside and outside the porosity of 25 to 35%. If the change in the acoustic intensity of the reflected sound is small or does not change inside or outside the allowable range, there is a possibility that the evaluation cannot be performed correctly.

  As shown in FIG. 5A, when the horizontal axis is the void ratio and the vertical axis is the output Po of the second acoustic sensor 34, the acoustic intensity at the boundary and inside of the allowable range, as indicated by a broken line or a dashed line. In the case where the change of is small or hardly changes, the correlation with the porosity cannot be found properly. Even in such a case, the correlation can be obtained by adjusting the length L of the gap formed between the boundary wall 30 and the porous body 5. In the present embodiment, when the gap length L is set in the range of 15 to 30 mm, preferably in the range of 20 to 30 mm, in the range of the porosity of 25 to 35% and its boundary region, it becomes large as shown by the solid line in the figure. An inclined favorable characteristic can be obtained.

  That is, by adjusting the gap L formed between the boundary wall 30 and the porous body 5, the influence of the directly propagated acoustic intensity is minimized and the reflected acoustic intensity from the porous body 5 is maximized. To be able to balance.

  FIG. 4B shows the measurement principle of the porosity measuring device 20. The acoustic intensity of the direct sound output from the sound source 30 installed in the first sound insulation chamber 21 is detected by the first acoustic sensor 32, enters the porous body 5 through the openings 24 and 25, and is reflected by the porous body 5. The reflected sound and the acoustic intensity of the direct sound that has passed through the gap width L of the boundary wall 23 are detected by the second acoustic sensor 34 installed in the second sound insulation chamber 22.

  There is a correlation between the ratio (Pi / Po, or 10 Log (Pi / Po)) of the output Pi of the first acoustic sensor 32 and the output Po of the second acoustic sensor 34 and the porosity of the porous body 5. Therefore, it can be evaluated whether or not the porosity of the porous body is within an allowable range.

  That is, when the porosity of the porous body 5 is large, the sound output from the sound source 30 is greatly absorbed and attenuated by the porous body 5, so that the acoustic intensity of the reflected sound is reduced and the porosity of the porous body 5 is reduced. When the rate is small, the sound output from the sound source 30 is not so much attenuated and attenuated by the porous body 5, so that the acoustic intensity of the reflected sound becomes relatively large. As a result, it can be evaluated whether or not the porosity of the porous body to be measured is within an allowable range. Note that there is also a correlation between the difference (Pi−Po) between the output Pi of the first acoustic sensor 32 and the output Po of the second acoustic sensor 34 and the porosity of the porous body 5. Any value can be evaluated. Below, the example which uses a difference is demonstrated.

  A non-sound-absorbing blocking member that blocks a region other than the predetermined width region W facing the lower end of the boundary wall 23 among the openings 24 and 25 facing the porous body 5 of the first sound insulating chamber 21 and the second sound insulating chamber 22. (Sheet) 27 and 28 are installed. As the closing member, a sheet made of polyvinyl chloride is used.

  The region where the direct sound output from the sound source 30 is incident on the porous body 5 is limited to a region having a predetermined width W (see FIG. 3C) facing the lower end of the boundary wall 23 by the blocking members 27 and 28. Therefore, even if the intensity of the sound source 30 is not increased so much, the degree of attenuation by the porous body 5 can be detected efficiently and accurately. The predetermined width W includes the thickness of the boundary wall 23 of 35 mm, preferably in the range of 100 to 160 mm, and more preferably in the range of 120 to 140 mm.

  Furthermore, it is preferable that a close contact member is provided in which the peripheral end faces of the openings 24 and 25 are in close contact with the surface of the porous body 5, and even if the surface of the porous body 5 is uneven, the close contact member Since such a gap is closed, it is possible to prevent acoustic energy output from the sound source 30 from leaking out of the gap or external noise from entering the gap, thereby enabling accurate measurement.

  As the close contact member, an elastic member such as urethane foam covered with a polyvinyl chloride sheet can be suitably used. By covering the foamed urethane with the above-described non-sound-absorbing blocking members (sheets) 27 and 28, it is also possible to use the urethane foam as a close contact member.

  Further, the sound source 30 is configured by a speaker connected to a noise generator that outputs white noise of a predetermined intensity, and is individually set by the porous body 5 among the white noise in the first acoustic sensor 32 and the second acoustic sensor 34. A frequency band selection unit capable of selectively measuring the acoustic intensity of the frequency band. Furthermore, the noise generator may be provided with a frequency band selection unit that outputs only the frequency band set individually among the white noise.

  Even if the porosity of the porous body 5 to be measured is the same, the frequency range of the sound source to be attenuated is different if the average size or size distribution of each void is different. However, if the sound source 30 is composed of a speaker that outputs white noise of a predetermined intensity, there is no need to adjust the frequency of the sound source according to the average size or size distribution of the air gaps, and the first acoustic sensor 32 and the second acoustic sensor 34. A frequency band signal adapted to the size of the voids of the porous body 5 can be obtained via the frequency band selector provided in the above. If the measurement frequency band of the acoustic sensor can be adjusted, the apparatus can be generalized. Furthermore, the frequency band of the white noise output from the noise generator may be selected and output by the frequency band selection unit.

  If the frequency band adapted to the size of the gap of the porous body 5 is known, the sound source 30 can be constituted by a speaker that outputs sound in a frequency band individually set by the porous body 5. .

  When the object to be measured is the porous concrete layer 5 described above, in order to obtain an appropriate frequency band, white noise sound was output from the sound source 30 and octave analysis was performed. As a result, as shown in FIG. 5 (b), it was confirmed that the reduced sound volume Pi-Po shows a good correlation in the frequency band of 5k to 8kHz with respect to the range where the porosity is 25 to 35%. At this time, the gap length L of the boundary wall 23 is set to a range of 15 to 30 mm.

  That is, when measuring the porosity of a porous concrete floor placed in a filtration pond, the length L of the gap is set to 15 to 30 mm, and the selected frequency band of the acoustic sensor is 5 k to When it is set in the range of 8 kHz, the porosity can be evaluated satisfactorily.

  As shown in FIG. 4 (b), the porosity evaluation method according to the present invention evaluates the suitability of the porosity of the porous concrete floor placed in the filtration basin using the porosity measuring device 20 described above. The porosity evaluation method is such that the openings 24 and 25 of the first sound insulation chamber 21 and the second sound insulation chamber 22 face the porous body 5 and a predetermined sound is output from the sound source 30. A difference in acoustic intensity detected by the first acoustic sensor 32 and the second acoustic sensor 34 is calculated, and based on the calculated value, it is estimated whether or not the porosity of the porous body 5 is within an allowable range.

  The allowable range is set by executing a reference evaluation value calculation step and a determination reference value setting step. In the reference evaluation value calculating step, a plurality of calculated values are obtained by repeating measurement processing for calculating a difference in acoustic intensity, here, a reduced sound volume Pi-Po for a plurality of porous bodies having different porosity. In the judgment reference value setting step, the calculated value indicating the upper predetermined ratio (rejection rate) of the relative frequency distribution of the calculated value with respect to the porous body whose porosity is the upper limit of the allowable range is set to the allowable upper limit value, and the porosity is within the allowable range The calculated value indicating the lower predetermined ratio (rejection rate) of the relative frequency distribution of the calculated value with respect to the lower limit porous body is set as the allowable lower limit value, and the allowable upper limit value and the allowable lower limit value are set as the allowable range.

  In FIG. 9 (a), the length L of the gap is variably adjusted in the range of 15 to 30 mm for nine porous concrete samples having a porosity in the range of 25% to 35%. The distribution diagram characteristics of the reduced sound volume Pi-Po measured each time a plurality of times are shown.

  As shown in FIGS. 9B and 9C, the relative frequency for each sample almost shows a normal distribution. Therefore, the upper limit value and the lower limit value were determined with reference to the p value in statistics. The p value refers to the rejection rate of extreme numerical values (left and right end portions in the relative frequency distribution diagram) in the measurement data. Normally, the p value is a constant value between 5% and 10% of the rejection rate, but is set to a rejection rate of 20% in order to ensure the reliability of the measurement data, and an upper limit value and a lower limit value are calculated for each sample.

  As shown in FIGS. 9B and 9C, the highest upper limit value among the nine samples is 15.44 dB with a porosity of 34.5%, and the lowest lower limit value is with a porosity of 25. It was 9%, 10.54 dB. The dashed-dotted line shown in FIG. 9A is a line segment indicating the allowable upper limit value 15.44 dB and the allowable lower limit value 10.54 dB.

  That is, a reference evaluation value calculation step for obtaining an evaluation value by measurement using a porosity measuring device for a plurality of porous concrete floor samples having different values with known porosity, For floor samples showing porosity, set the upper limit judgment value as the upper limit judgment value from the relative frequency distribution of the evaluation value obtained in the reference evaluation value calculation step, and near the lower limit or lower limit of the allowable range And a determination reference value setting step for setting an evaluation value that is a lower predetermined ratio from the relative frequency distribution of the evaluation values obtained in the reference evaluation value calculation step to a lower limit determination value for a floor sample having a porosity of An upper limit value and a lower limit value used in the rate evaluation method are determined. It is preferable that the upper predetermined ratio and the lower predetermined ratio are set in a range of a rejection area of 5 to 20%.

Hereinafter, a specific procedure of the porosity evaluation method will be described.
As shown in FIG. 6A, in the case of a porous concrete layer having a pond area of 15000 mm in length and 3500 mm in width, for example, 30 small pieces of 1500 mm × 1170 mm square divided into 10 equal parts in the vertical direction and 3 equal parts in the horizontal direction. Dividing into regions, assigning numbers 1 to 30 to each small region, installing the porosity measuring device 20 in the center of each small region, calculating the volume reduction Pi-Po multiple times, and calculating the average value thereof It is a representative value of a small area. The size of the small region is preferably in the range of 1000 mm × 1000 mm to 2000 mm × 2000 mm.

  Note that the size of the area to be divided does not need to be set strictly, and may be a rectangle having a side of about 1 to 2 m, for example. It is more preferable that the size be a size that can be assumed that a value almost equal to the measurement value at the measurement position is obtained around the measurement position, or a size slightly larger than the size.

  When measuring a porous material with a large area, it takes a lot of time to measure it if it is measured many times with a fine measurement pitch. However, the porous material is divided into predetermined sizes and measured at least at one location for each section. Based on the calculated values obtained in this manner, efficient measurement can be performed by estimating whether the porosity of the entire area of the porous body is within the allowable range.

  FIG. 7A shows the volume reduction and the judgment value for the measurement points numbered 1 to 30, and FIG. 7B shows the distribution characteristics of the volume reduction at that time. .

  FIG. 8 shows evaluation procedures and evaluation criteria for determination. For each processing tank, a first evaluation step is executed to determine whether or not the volume reduction in each small region is within the allowable range of the allowable upper limit value of 15.44 dB and the allowable lower limit value of 10.54 dB (S1). When 80% or more of the number of small areas are within the allowable range (S1, Y), whether or not the volume reduction at each measurement point of the adjacent small areas does not deviate from the allowable range. The second evaluation step is executed. When both do not deviate from the permissible range (S2, Y), it is determined that the porous concrete floor portion is in the range of 25 to 35% porosity (S3). .

  In the first evaluation step, when it is determined that more than 20% of the number of small regions are not within the allowable range (S1, N), the porous evaluation is made without waiting for the second evaluation step. The floor is determined to be inappropriate (S5).

  If it is determined in the second evaluation step of step S2 that the volume reductions of the two adjacent small areas are both out of the allowable range, as shown in FIG. A predetermined distance centered on the position, for example, a circle having a radius of 500 mm, is set so that five remeasurement points are evenly spaced, and the volume reduction at each remeasurement point is the above-described allowable upper limit of 15.44 dB. Is determined to be within the allowable lower limit of 10.54 dB, and if it is determined that 80% (that is, four locations) are within the range (S4), step S2 is executed again. (S2).

  When the second evaluation step is executed in step S2 to determine whether or not the volume reduction at each measurement point of the adjacent small area does not deviate from the allowable range, and both do not deviate from the allowable range. (S2, Y), the porosity is in the range of 25 to 35%, and it is determined that the floor portion made of porous concrete is appropriate (S3).

  If the range of the small region is in the range of 1000 mm × 1000 mm to 2000 mm × 2000 mm, the five remeasurement points are evenly distributed within the small region and separated from each other by about 500 mm, so that sufficient measurement accuracy can be obtained. . That is, it is desirable that the measurement points for remeasurement should be a plurality of measurement points that are evenly distributed within the small area with respect to the first measurement point.

  According to this procedure, the porous concrete layer showing the volume reduction distribution characteristic of FIG. 7B deviates from the allowable range in the small region of number 20, but is within the allowable range in the other small regions. The above evaluation criteria are satisfied and it is determined that the construction state is appropriate.

  If there is a problem in the pouring method or compacting method of porous concrete, it will have a great influence on water treatment in a wide range. Therefore, a broad definition is defined as two or more adjacent small regions. The adjacent direction of the region is a concept including not only the front-rear direction and the up-down direction but also the oblique direction.

  That is, the porosity evaluation method according to the present invention has an area division step for dividing a porous concrete floor portion into a predetermined size, and an evaluation value by measurement using a porosity measurement device at least at one location for each of the divided areas. And a first evaluation step for determining whether or not an evaluation value for each category obtained in the individual measurement step exists between a predetermined upper limit determination value and a lower limit determination value; And a second evaluation step for obtaining a distribution state of the deviation section where the evaluation value does not exist between the upper limit determination value and the lower limit determination value, for example, the number of adjacent deviation sections.

  The first evaluation step includes a third evaluation step for calculating a ratio of the number of sections in which each evaluation value exists between a predetermined upper limit determination value and a lower limit determination value to the total number of sections, and the ratio is more than a predetermined reference ratio. And a fourth evaluation step for evaluating that the void ratio of the floor portion is appropriate when the number of adjacent deviation segments obtained in the second evaluation step is smaller than a predetermined reference number.

  When the number of adjacent deviation segments obtained in the second evaluation step is equal to or greater than a predetermined reference number, the porosity measurement device at a plurality of positions separated by a predetermined distance from the measurement location measured in the measurement step for each adjacent segment A re-measurement step is performed to obtain an evaluation value by measurement using and the ratio of the number of measurement positions where the evaluation value obtained in the re-measurement step is between the upper limit determination value and the lower limit determination value is greater than or equal to a predetermined ratio Sometimes, the second evaluation step is executed again by evaluating that the classification exists between the upper limit determination value and the lower limit determination value.

  Divide the floor area made of porous concrete with a large area into a predetermined size, and calculate the ratio or difference of the sound intensity at at least one location for each section. Based on the calculated value, the porosity of the entire floor area is acceptable. If the calculated value deviates from the allowable range, the sound intensity ratio or difference is calculated at a plurality of positions separated by a predetermined distance from the measurement location, and the calculated value is within the allowable range. When the ratio of the number of measurement positions is equal to or greater than a predetermined ratio, it is estimated that the category is within the allowable range.

  In the embodiment described above, the porosity measuring device that mainly measures the porosity of the floor portion made of porous concrete placed in the filtration pond has been described. However, the measurement target of the porosity measuring device according to the present invention is porous concrete. The present invention can be applied to other than the floor portion made of a product, and the porosity of an arbitrary porous body can be measured.

  When evaluating the porosity of the porous concrete layer, it is preferable that the length L of the gap is set to 15 to 30 mm and the selection frequency band of the acoustic sensor is set to a range of 5 to 8 kHz. The length L of the part and the selected frequency band of the acoustic sensor are values that are appropriately set according to the measurement target.

  In the above-described embodiment, the gap adjusting mechanism 40 is provided in the boundary wall 23 and the porosity measuring device having versatility has been described. However, the boundary wall 23 and the porous body 5 are not provided without the gap adjusting mechanism 40. The length of the gap formed between the two may be set to an appropriate value in advance according to the measurement target.

  In the above-described embodiment, the case where the sound insulation chambers 21 and 22 have a rectangular parallelepiped shape has been described. However, the sound insulation chambers 21 and 22 may be partitioned by the boundary wall 23, and the shape is not particularly limited. For example, the sound insulation chambers 21 and 22 may be formed of a cylindrical body having a curved peripheral wall.

  In the embodiment described above, the first sound insulation chamber and the second sound insulation chamber having an opening formed on one end side so as to face the porous body are disposed adjacent to each other through the boundary wall, and the sound source is installed in the first sound insulation chamber. And a first acoustic sensor for measuring the acoustic intensity of the direct sound output from the sound source, and a gap of a predetermined size formed between the boundary wall and the porous body output from the sound source in the second sound insulation chamber. The porosity evaluation method using the porosity measuring device in which the second acoustic sensor for measuring the reflected acoustic intensity from the porous body propagating from the part has been described. However, the porosity evaluation method itself has the above-described configuration. A porosity measuring device that can be employed even when using a porosity measuring device other than the porosity measuring device equipped with the above, and that determines the porosity of the porous body by measuring the reflected acoustic intensity from the porous body. For example, use a porosity measuring device of any configuration It can be assessed porosity.

  The construction method of the filtration basin by this invention is employ | adopted when constructing the filtration pond by which the porosity is evaluated by the above-mentioned porosity evaluation method. That is, for the porous concrete floor placed in the filter basin, when the porosity is evaluated as appropriate by the porosity evaluation method, the filter basin is completed by filling the top of the floor with a filter medium, If the void ratio is evaluated as negative by the void ratio evaluation method, measures such as re-construction are taken so that the void ratio is evaluated as appropriate by the void ratio evaluation method.

  The soundness evaluation method of the filtration pond according to the present invention is to compare the evaluation value before use and the evaluation value after use measured by the porosity evaluation method described above with respect to the porous concrete layer placed in the filtration pond. This evaluates the soundness of the filtration pond.

  When used for a long period of time, the pores of the porous concrete constituting the floor of the filtration basin are gradually clogged, so that the function can be restored by regular backwashing. When using for a long period of time, it is possible to properly evaluate the soundness of the filtration pond by comparing the evaluation value before use and the evaluation value after use measured by the porosity evaluation method described above. It is possible to reliably grasp the situation where the function cannot be restored by backwashing. In particular, it is preferable to obtain an evaluation value by measuring at the time of replacement of activated carbon, anthracite, or the like which is a filter medium. As a result, if it can be evaluated that it is healthy, a new filter medium is installed. If it is not healthy, it is judged that the porous concrete floor has deteriorated, and re-construction is examined.

  The above-described embodiment is one aspect of the present invention, and the present invention is not limited by the description. Specific configurations and control aspects of each part can be appropriately changed and designed within the scope of the effects of the present invention. Needless to say.

5: Porous body 20: Porosity measuring device 21: first sound insulation chamber 22: second sound insulation chamber 23: boundary wall 30: sound source 32: first acoustic sensor 34: second acoustic sensor

Claims (8)

A porosity evaluation method for evaluating the suitability of the porosity of a porous concrete floor placed in a filtration pond using a predetermined porosity measuring device,
Measurement including an area dividing step of dividing the porous concrete floor into a predetermined size, and an individual measuring step of obtaining an evaluation value by measurement using the porosity measuring device at least at one location for each of the divided areas Steps,
A first evaluation step for determining whether or not an evaluation value for each category obtained in the individual measurement step exists between a predetermined upper limit determination value and a lower limit determination value;
A second evaluation step of obtaining the number of adjacent departure sections as a distribution state of departure sections where the evaluation value does not exist between the upper limit determination value and the lower limit determination value;
Equipped with a,
The first evaluation step includes a third evaluation step of calculating a ratio of the number of sections in which each evaluation value exists between a predetermined upper limit determination value and a lower limit determination value to the total number of sections, and the ratio is a predetermined reference ratio A void ratio that includes a fourth evaluation step that evaluates that the void ratio of the floor portion is appropriate when the number of adjacent deviation sections obtained in the second evaluation step is less than a predetermined reference number. Evaluation method. When the number of adjacent deviation segments obtained in the second evaluation step is equal to or greater than a predetermined reference number, the gaps are spaced at a predetermined distance from the measurement points measured in the measurement step for each adjacent segment. A re-measurement step of obtaining an evaluation value by measurement using a rate measuring device is executed, and a ratio of the number of measurement positions where the evaluation value obtained in the re-measurement step exists between the upper limit determination value and the lower limit determination value is predetermined. when it is the ratio above, it was evaluated and its division exists between the upper threshold value and the lower limit determination value, the porosity evaluation method according to claim 1, wherein executing the second evaluation step again. A reference evaluation value calculation step for obtaining an evaluation value by measurement using the porosity measuring device for a plurality of floor concrete samples made of porous concrete having different values of porosity, and
An upper predetermined ratio from the relative frequency distribution of the evaluation values obtained in the reference evaluation value calculation step with respect to the floor sample showing the upper limit of the predetermined allowable range or the porosity in the vicinity of the upper limit of the plurality of floor samples. Is set to the upper limit determination value, and is obtained in the reference evaluation value calculating step for a floor sample having a porosity near a lower limit or a lower limit of a predetermined allowable range among the plurality of floor samples. A determination reference value setting step for setting, as the lower limit determination value, an evaluation value that is a lower predetermined ratio from the relative frequency distribution of the evaluation values,
The porosity evaluation method of Claim 1 or 2 containing these. A porosity evaluation method for evaluating the suitability of the porosity of a porous concrete floor placed in a filtration pond using a predetermined porosity measuring device,
Measurement including an area dividing step of dividing the porous concrete floor into a predetermined size, and an individual measuring step of obtaining an evaluation value by measurement using the porosity measuring device at least at one location for each of the divided areas Steps,
A first evaluation step for determining whether or not an evaluation value for each category obtained in the individual measurement step exists between a predetermined upper limit determination value and a lower limit determination value;
A second evaluation step of obtaining the number of adjacent departure sections as a distribution state of departure sections where the evaluation value does not exist between the upper limit determination value and the lower limit determination value;
With
When the number of adjacent deviation segments obtained in the second evaluation step is equal to or greater than a predetermined reference number, the gaps are spaced at a predetermined distance from the measurement points measured in the measurement step for each adjacent segment. A re-measurement step of obtaining an evaluation value by measurement using a rate measuring device is executed, and a ratio of the number of measurement positions where the evaluation value obtained in the re-measurement step exists between the upper limit determination value and the lower limit determination value is predetermined. A porosity evaluation method configured to evaluate that the classification exists between the upper limit determination value and the lower limit determination value when the ratio is equal to or greater than the ratio, and to execute the second evaluation step again. A porosity evaluation method for evaluating the suitability of the porosity of a porous concrete floor placed in a filtration pond using a predetermined porosity measuring device,
Measurement including an area dividing step of dividing the porous concrete floor into a predetermined size, and an individual measuring step of obtaining an evaluation value by measurement using the porosity measuring device at least at one location for each of the divided areas Steps,
A first evaluation step for determining whether or not an evaluation value for each category obtained in the individual measurement step exists between a predetermined upper limit determination value and a lower limit determination value;
A second evaluation step of obtaining the number of adjacent departure sections as a distribution state of departure sections where the evaluation value does not exist between the upper limit determination value and the lower limit determination value;
A reference evaluation value calculation step for obtaining an evaluation value by measurement using the porosity measuring device for a plurality of floor concrete samples made of porous concrete having different values of porosity, and
An upper predetermined ratio from the relative frequency distribution of the evaluation values obtained in the reference evaluation value calculation step with respect to the floor sample showing the upper limit of the predetermined allowable range or the porosity in the vicinity of the upper limit of the plurality of floor samples. Is set to the upper limit determination value, and is obtained in the reference evaluation value calculating step for a floor sample having a porosity near a lower limit or a lower limit of a predetermined allowable range among the plurality of floor samples. A determination reference value setting step for setting, as the lower limit determination value, an evaluation value that is a lower predetermined ratio from the relative frequency distribution of the evaluation values,
A porosity evaluation method comprising: The void ratio evaluation method according to claim 3 or 5, wherein the upper predetermined ratio and the lower predetermined ratio are set in a range of a rejection area of 5 to 20%. Simplify assumptions
A method for constructing a filter basin configured such that treated water permeates downward and cleaning air permeates upward through a floor made of porous concrete placed in the filter basin,
When the porosity evaluation method according to any one of claims 1 to 6 is performed on the porous concrete floor placed in the filtration basin, and the porosity is evaluated as appropriate, the floor A filter pond construction method in which a filter medium is filled in an upper portion of the filter and the porosity evaluation method determines that the porosity is negative, and measures such as re-construction of the porous concrete are taken. A method for evaluating the soundness of a filtration pond configured such that treated water permeates downward and cleaning air permeates upward through a floor made of porous concrete placed in the filtration pond,
The porosity evaluation method according to any one of claims 1 to 6 is executed for the porous concrete layer placed in the filtration basin, and the measured evaluation value before use is compared with the evaluation value after use. A filter basin soundness evaluation method that evaluates the soundness of the filter basin.