CN217466780U - Parameter calibration device of FDR sensor - Google Patents
Parameter calibration device of FDR sensor Download PDFInfo
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- CN217466780U CN217466780U CN202221166714.6U CN202221166714U CN217466780U CN 217466780 U CN217466780 U CN 217466780U CN 202221166714 U CN202221166714 U CN 202221166714U CN 217466780 U CN217466780 U CN 217466780U
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Abstract
The utility model discloses a convenient FDR sensor parameter calibration device. The device consists of a water content control system, a temperature control system and a data monitoring system; the water content control system consists of an electronic scale, an ultrasonic humidifier, a hygrothermograph, a humidity circulating pump, a humidity circulating pipeline, a constant temperature and humidity curing box and a sample barrel; the temperature control system consists of a constant-temperature water bath tank, a temperature circulating pump, a temperature circulating pipeline and a spiral copper pipe; the data acquisition system consists of a data acquisition box, an FDR sensor and a displacement sensor; and (4) calibrating to obtain the corresponding relation between the water content and the dielectric constant through a device test and using the FDR sensor for directly measuring the mass water content of the soil body. The device of the utility model can be directly used for detecting the water content of the soil mass; the calibration test can be carried out under the condition of preparing a small amount of calibration samples, the uniformity of the calibration samples is ensured while the workload is reduced, and the sensor parameters can be calibrated more accurately.
Description
Technical Field
The utility model relates to a soil body moisture content short-term test technical field specifically is a FDR sensor parameter calibration device.
Background
The water content of soil is an important physical parameter for reflecting the water condition of soil body, and how to accurately and efficiently measure the water content of the soil body is a key concern in engineering. The conventional moisture content measuring method mainly comprises a drying method, a neutron instrument method, a tension method, a dielectric method and the like, compared with other methods, the dielectric method has the characteristics of high efficiency, convenience and no pollution, and a Frequency Domain Reflection (FDR) method in the dielectric method has the advantages of good stability, high accuracy and low cost and is widely applied at home and abroad.
The working principle of the frequency domain reflection method is that the oscillation of an LC circuit is utilized, the apparent dielectric constant of the soil body is measured according to the change of the oscillation frequency of electromagnetic waves in the soil body, and then the volume water content of the soil body is calculated through a certain corresponding relation. The gravity water content of the soil body is more concerned in engineering, and the existing calibration method of the FDR sensor can only be used for detecting the volume water content. It is necessary to develop a new calibration method so that the FDR sensor can directly measure the mass water content of the soil body.
The measurement result of the frequency domain reflection method is easily influenced by complex factors such as soil composition, salinity, pH value, temperature and the like, and parameter calibration of the FDR sensor needs to be carried out on different soil before application. In a conventional calibration test, a large number of calibration samples in different states are prepared, FDR sensors are sequentially inserted under different temperature environments for dielectric constant measurement, and then sensor parameters are calibrated. The conventional calibration test wastes time and labor, and under the condition of low or high water content, a calibration sample meeting certain compactness and uniformity requirements is difficult to prepare, sensor parameters cannot be accurately calibrated, and the popularization and application of a frequency domain reflection method are seriously influenced.
Disclosure of Invention
The utility model discloses a convenient FDR sensor parameter calibration device. The FDR technology of the utility model can be directly used for detecting the mass water content of the soil body; the calibration test can be carried out under the condition of preparing a small amount of calibration samples, the uniformity of the calibration samples is ensured while the workload is reduced, and the sensor parameters can be calibrated more accurately.
The utility model discloses a following technical scheme realizes:
parameter calibration device of FDR sensor, its characterized in that: the water content control system is composed of a water content control system, a temperature control system and a data monitoring system;
the water content control system consists of an electronic scale, an ultrasonic humidifier, a hygrothermograph, a humidity circulating pump, a humidity circulating pipeline, a constant temperature and humidity curing box and a sample barrel; the constant temperature and humidity curing box is a closed container; the bottom of the container is provided with an ultrasonic humidifier, and a humidity circulating pump is in circulating communication with the container through a humidity circulating pipeline; the bottom of the container is provided with an electronic scale, and a sample barrel for containing a sample is placed on the electronic scale;
the temperature control system consists of a constant-temperature water bath tank, a temperature circulating pump, a temperature circulating pipeline and a spiral copper pipe; the spiral copper pipe is circularly arranged on the inner wall of the container of the constant-temperature and constant-humidity curing box in a surrounding manner, and two ends of the spiral copper pipe are circularly communicated with the constant-temperature water bath box and the temperature circulating pump through temperature circulating pipelines;
the data acquisition system consists of a data acquisition box, an FDR sensor and a displacement sensor; the FDR sensor is arranged on the wall of the sample barrel, the displacement sensor is arranged on the top of the container of the constant-temperature and constant-humidity curing box, and the FDR sensor and the displacement sensor are in signal connection with the data acquisition box.
And further, the FDR sensor is a probe type FDR displacement sensor, the probe is positioned in the sample barrel, and the FDR sensor is a wireless acquisition sensor.
Furthermore, the wall of the sample cylinder is uniformly provided with open pores, the diameter of each open pore is 5mm, the inner diameter of the sample cylinder is 300mm, the outer diameter of the sample cylinder is 310mm, and the height of the sample cylinder is 200 mm.
Further, the displacement sensor is a laser displacement sensor.
Further, the heat-conducting medium in the constant-temperature water bath tank is silicone oil.
The utility model discloses the device carries out parameter calibration through following method:
the corresponding relation between the water content and the dielectric constant;
1) taking test soil, preparing soil samples with different water contents, preparing calibration samples with different water contents and dry densities in a sample barrel, recording data such as volume water content, mass water content and dry density of a soil body, and measuring the dielectric constant of the calibration samples by using an FDR sensor at constant temperature;
2) substituting the volume water content and the dielectric constant data of the calibration test into a calibration formula of the corresponding relation to fit sensor parameters; substituting the mass water content and dry density data of the calibration test into a calibration formula of the corresponding relation to fit sensor parameters;
3) deducing the relationship among the volume water content, the mass water content and the dry density, and combining the two calibration formulas in the step 2) to obtain the corresponding relationship between the mass water content and the dielectric constant; and after all parameters are calibrated, the FDR sensor is used for directly measuring the mass water content of the soil body.
Measuring the water content; and the FDR sensor is used for directly measuring the mass water content of the soil body, and the obtained dielectric constant measured value obtains the corresponding water content according to the corresponding relation between the water content and the dielectric constant.
The utility model provides a convenient and efficient FDR sensor parameter calibration device. Compared with the prior art, the method has the following beneficial effects:
1) the calibration method of current FDR sensor can only make it be used for the volume moisture content to detect, the utility model discloses the influence of dry density is introduced when considering dielectric constant and volume moisture content relation to the calibration device, can directly obtain soil mass moisture content through calculating.
2) The utility model can complete the calibration test under the condition of only preparing a small amount of calibration samples, thereby greatly reducing the workload of the calibration test of the FDR sensor; all the calibration tests are completed on one sample, so that the influence of sample preparation discrete type on the calibration result is effectively avoided.
3) The utility model discloses the calibration device and test method thereof utilize laser displacement sensor can be at the altitude variation of measuring the sample under the condition with the sample contact not, and the usable wireless communication technique of wireless FDR sensor directly transmits the signal that gathers for data acquisition system, has effectively avoided the influence of contact problem to electronic scale measuring result, has guaranteed measuring accuracy.
Drawings
Fig. 1 is a schematic structural view of an FDR sensor parameter calibration device.
FIG. 2 is a schematic view of the structure of the curing box.
Fig. 3 is a schematic view of a sample barrel structure.
In the figure, 1, an electronic scale; 2. an ultrasonic humidifier; 3. a hygrothermograph; 4. a humidity circulating pump; 5. a humidity circulation pipe; 6. a constant temperature and humidity curing box; 7. a sample barrel; 8. a constant temperature water bath box; 9. a temperature circulating pump; 10. a temperature circulating pipeline; 11. a spiral copper pipe; 12. a wireless collection box; 13. an FDR sensor; 14. a displacement sensor; 15. a sample; 16. and (6) opening holes.
Detailed Description
The present invention will be further described with reference to the following embodiments, which are intended to illustrate the principles of the present invention without limiting the present invention in any way, and the present invention is not beyond the scope of the present invention.
As shown in fig. 1, fig. 2 and fig. 3, the utility model discloses a parameter fast calibration device of FDR sensor includes: moisture content control system, temperature control system, data monitoring system:
the moisture content control system comprises an electronic scale 1, an ultrasonic humidifier 2, a temperature and humidity meter 3, a humidity circulating pump 4, a humidity circulating pipeline 5, a constant temperature and humidity curing box 6 and a sample barrel 7.
A sample barrel 7 is placed on an electronic scale 1, the ultrasonic humidifier 2 is used for generating humid air with constant humidity, the humid air is driven by a humidity circulating pump 4 to enter a constant-temperature and constant-humidity curing box 6 through a humidity circulating pipeline 5, and the sample is humidified/dehumidified.
The temperature control system comprises a constant temperature water bath tank 8, a temperature circulating pump 9, a temperature circulating pipeline 10 and a spiral copper pipe 11.
Utilize constant temperature water bath 8 to carry out temperature control to heat-conducting medium, make heat-conducting medium at spiral copper pipe 11 inner loop through the drive of temperature circulating pump 9, carry out temperature control to the environment that the sample is located, constant temperature and humidity curing box 6 adopts the heat-insulating material to make, reducible incasement and external heat exchange.
The data acquisition system comprises a data acquisition box 12, an FDR sensor 13 and a displacement sensor 14, wherein data acquired by the FDR sensor 13 and the displacement sensor 14 are directly transmitted to the data acquisition box 12. The FDR sensor 13 is used for collecting the dielectric constant of the sample, and parameters of a fitting equation of the corresponding relation between the dielectric constant and the volume water content can be calibrated according to the collection result; the displacement sensor is used for collecting the wet expansion/dry shrinkage deformation of the sample, and the real-time volume and more accurate volume water content of the sample can be calculated according to the collection result.
The FDR sensor 13 is a probe-type FDR displacement sensor, and is a wireless acquisition sensor.
The sample tube 7 had an inner diameter of 300mm, an outer diameter of 310mm and a height of 200 mm. The opening of the sample cylinder 7 has a diameter of 5 mm.
The displacement sensor 14 is a laser displacement sensor.
The constant temperature and humidity curing box 6 is made of EPS foam boards.
The sample cylinder 7 is made of organic glass.
The heat-conducting medium in the constant-temperature water bath tank 8 is silicone oil.
The utility model discloses FDR sensor's parameter is rateed fast and is rateed the rate of device and use and specifically include following step:
1) the test soil is subjected to tedding, air drying and grinding treatment, and then compaction test is carried out to obtain the maximum dry density and the optimal water content; and (3) preparing soil near the optimal water content, preparing 3-4 standard calibration samples with different densities in the sample barrel, and recording the initial volume, the initial volume water content and the initial mass water content of the standard calibration samples.
2) And inserting the FDR sensors into standard calibration samples with different densities in sequence, placing the standard calibration samples on an electronic scale in a constant-temperature and constant-humidity curing box, and starting a humidity control system and a temperature control system to humidify or dehumidify the calibration samples in a grading manner at constant temperature. In the humidification or dehumidification process, the electronic scale is used for recording the mass change of the sample, the displacement sensor is used for recording the height change of the sample, and the dielectric constant detected by the FDR sensor is recorded in real time.
3) After the sample is humidified or dehumidified stably, calculating the mass water content of the sample according to data recorded by the electronic scale; calculating the volume change of the sample according to the data recorded by the displacement sensor, and further calculating to obtain the volume water content and the dry density of the sample; and (5) counting the corresponding relation among the dielectric constant, the dry density, the volume water content and the mass water content.
4) And (3) according to the test result, calibrating parameters of a fitting equation of the corresponding relation between the dielectric constant and the volume water content, wherein the form of the fitting equation is as follows:
in the formula: theta is the volume water content; k a Is the dielectric constant; A. b, C, D are all calibration parameters.
5) And (3) according to the test result, calibrating parameters of a fitting equation of the corresponding relation of the dielectric constant, the mass water content and the dry density, wherein the form of the fitting equation is as follows:
in the formula: omega is the mass water content; rho w Is the density of water; rho d Is the dry density of the soil; E. f is a calibration parameter.
6) Deducing the relation between the mass water content and the dielectric constant, wherein the relation between the mass water content and the volume water content is as follows:
θ＝ωρ d (3)
the relationship between the mass water content and the dielectric constant can be obtained by the simultaneous formulas (1), (2) and (3):
all the parameters are calibrated through the steps, and the direct measurement of the volume water content of the soil body can be carried out according to a formula (4).
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the above embodiments, and that the foregoing embodiments and descriptions are provided only to illustrate the principles of the present invention without departing from the spirit and scope of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (5)
1. A parameter calibration device of an FDR sensor is characterized in that: the water content control system is composed of a water content control system, a temperature control system and a data monitoring system;
the water content control system consists of an electronic scale, an ultrasonic humidifier, a hygrothermograph, a humidity circulating pump, a humidity circulating pipeline, a constant temperature and humidity curing box and a sample barrel; the constant temperature and humidity curing box is a closed container; the bottom of the container is provided with an ultrasonic humidifier, and a humidity circulating pump is in circulating communication with the container through a humidity circulating pipeline; the bottom of the container is provided with an electronic scale, and a sample barrel for containing a sample is placed on the electronic scale;
the temperature control system consists of a constant-temperature water bath tank, a temperature circulating pump, a temperature circulating pipeline and a spiral copper pipe; the spiral copper pipe is circularly arranged on the inner wall of the container of the constant-temperature and constant-humidity curing box in a surrounding manner, and two ends of the spiral copper pipe are circularly communicated with the constant-temperature water bath box and the temperature circulating pump through temperature circulating pipelines;
the data acquisition system consists of a data acquisition box, an FDR sensor and a displacement sensor; the FDR sensor is arranged on the wall of the sample barrel, the displacement sensor is arranged on the top of the container of the constant-temperature and constant-humidity curing box, and the FDR sensor and the displacement sensor are in signal connection with the data acquisition box.
2. The FDR sensor parameter calibration apparatus of claim 1, wherein: the FDR sensor is a probe type FDR displacement sensor, a probe is positioned in the sample bucket, and the FDR sensor is a wireless acquisition sensor.
3. The FDR sensor parameter calibration apparatus of claim 1, wherein: the wall of the sample tube is uniformly provided with open pores, the diameter of each open pore is 5mm, the inner diameter of the sample tube is 300mm, the outer diameter of the sample tube is 310mm, and the height of the sample tube is 200 mm.
4. The FDR sensor parameter calibration apparatus of claim 1, wherein: the displacement sensor is a laser displacement sensor.
5. The FDR sensor parameter calibration apparatus of claim 1, wherein: and the heat-conducting medium in the constant-temperature water bath tank is silicone oil.
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| CN202221166714.6U CN217466780U (en) | 2022-05-16 | 2022-05-16 | Parameter calibration device of FDR sensor |
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| CN202221166714.6U CN217466780U (en) | 2022-05-16 | 2022-05-16 | Parameter calibration device of FDR sensor |
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