JPH095269A - Device and method for measuring water content ratio of sample - Google Patents

Abstract

PURPOSE: To determine the water content ratio of a soil sample promptly on the site and to prevent practically occurrence of a measuring error of the water content ratio of the soil sample, by a simple device. CONSTITUTION: A water content ratio measuring device 1 is equipped with an insulative and transparent cylindrical vessel 2 in which a sample is put. It is equipped also with electrode plates 31 and 32 provided opposite on the inner circumferential surface 21 of the cylindrical vessel 2 and with an AC power source 4 connected to these electrode plates 31 and 32 and making a prescribed current flow through the soil sample put in the cylindrical vessel 2. Besides, it is equipped with a potentiometer 5 connected to the electrode plates 31 and 32, in series with the AC power source 4. On the inner circumferential surface of the cylindrical vessel 2, linear markings 61 and 62 are provided at a height of a half of the height from the bottom part of the cylindrical vessel 2 to the entrance part thereof and at a height of two thirds thereof respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for measuring the water content of soil samples.

[0002]

2. Description of the Related Art When it is necessary to measure the water content of a soil sample such as a fill material at an embankment site such as a fill dam core material embankment site or a soil sample at the current position by boring, etc. Conventionally, it was measured by the following means.

That is, conventionally, the weight of a soil sample is measured, and the sample is dried in a drying oven or the like at about 110 ° C. for 18 to 24 hours.
The water content ratio was obtained by drying over a period of time to make a sample in an absolutely dry state, measuring the weight of the sample again, and calculating the ratio between the weight reduced by drying and the weight of the sample in an absolutely dry state. .

[0004]

However, in the prior art, equipment such as a drying furnace is required to bring the sample into an absolutely dry state, and about one day is required to bring the sample into an absolutely dried state. Therefore, it was not possible to immediately obtain the water content ratio of the sample on site.

An object of the present invention is to make it possible to immediately determine the water content of a soil sample on site by using a simple device.

Further, another object is to prevent an error in measuring the water content of the soil sample from occurring easily.

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 is an apparatus for measuring a water content ratio of a sample, wherein the sample is an insulating transparent cylindrical container, and the cylindrical container. Two electrodes provided facing each other on the inner peripheral surface of the container, a power supply connected to the two electrodes for supplying a constant current to the sample in the cylindrical container, and the power supply connected in series to the two electrodes. And a potentiometer that is operated.

According to a second aspect of the present invention, in the apparatus for measuring the water content ratio of the sample according to the first aspect, the power source is an AC power source.

According to a third aspect of the present invention, in the sample water content measuring apparatus according to the first or second aspect, the cylindrical container is a standard for judging the amount of the sample contained in the container. It is characterized in that a mark that becomes is provided.

According to a fourth aspect of the present invention, in a method for measuring a water content ratio of a sample, the apparatus for measuring the water content ratio of the sample according to any one of the first to third aspects is prepared, and the sample is placed in the cylindrical container. After closing the upper lid to fill the sample, a constant current is applied to the sample in the cylindrical container by the power source to measure the potential difference between the two measuring electrodes with the potentiometer to obtain the resistance value of the sample. , Data showing a correlation between the resistance value of each sample and the water content ratio of each sample, which are obtained in advance by the same means,
The feature is that the water content ratio of the sample is determined by collating with the resistance value obtained this time.

According to a fifth aspect of the present invention, in the method for measuring a water content of a sample according to the fourth aspect, when filling the sample in the cylindrical container, the sample is compacted with a load that does not exceed a certain value. It is characterized in that it is filled in a cylindrical container in a plurality of times.

[0012]

According to the apparatus for measuring water content of a sample described in claim 1, after the insulating cylindrical container is filled with the sample, a constant current is applied to the sample in the cylindrical container by the power source to cause a gap between the two electrodes. The resistance value of the sample is obtained by measuring the potential difference of the sample with a potentiometer. Then, the water content ratio of the sample is measured by collating the data showing the correlation between the resistance value of the sample and the water content ratio of the sample, which are previously obtained by the same means, with the resistance value obtained this time. be able to.

Therefore, unlike the conventional case, it is not necessary to spend one day to dry the sample in a drying oven or the like to bring it into an absolutely dry state, and the water content of the soil sample can be immediately obtained on site. . Moreover, the apparatus configuration of the present invention is simple as described above, and does not require a conventional drying furnace or the like, so that the water content of the soil sample can be obtained with a simple apparatus.

Further, since the cylindrical container has a cylindrical shape, the cylindrical container is relatively difficult to be deformed even if it is formed thinly, the spread of the electric field from the electrode is kept constant, and the resistance value of the sample is reduced. The measurement result can be stabilized.

Therefore, it is possible to prevent the measurement error of the water content ratio of the soil sample due to the non-constant electric field.

Further, by controlling the amount of the sample in the container while visually observing the inside of the container through the transparent cylindrical container, the measurement error of the resistance value of the sample due to the amount of the input sample is less likely to occur.

Therefore, it is possible to prevent the measurement error of the water content ratio of the soil sample due to the amount of the input sample from increasing.

According to the water content measuring apparatus for a sample described in claim 2, the same operation as the water content measuring apparatus for a sample described in claim 1 is achieved, and the power source is an AC power source.
The polarization of the sample can be prevented by reversing the direction of the electric field applied to the sample from the electrodes, and the measurement error of the resistance value of the sample is less likely to occur.

Therefore, the measurement error of the water content ratio of the soil sample due to the polarization of the sample can be suppressed.

According to the water content measuring apparatus for a sample described in claim 3, the same operation as the water content measuring apparatus for a sample described in claim 1 or 2 is achieved, and in the cylindrical container. By loading the sample using the provided marks as a guide, the amount of the sample in the container is controlled, and the measurement error of the resistance value of the sample due to the amount of the loaded sample is less likely to occur.

Therefore, it is possible to prevent the measurement error of the water content ratio of the soil sample from occurring due to the amount of the input sample.

According to the water content measuring method of the sample described in claim 4, it is not necessary to spend one day to dry the sample in a drying oven or the like as in the conventional case, The water content of soil samples can be immediately obtained on-site. Moreover, the structure of the measuring device used is simple as described above, and since the conventional drying furnace is not required, the water content of the soil sample can be obtained with a simple device.

Further, if the measuring device is the one described in claim 2, it is possible to prevent the measurement error of the water content ratio of the soil sample due to the polarization of the sample as described above. If it is one, it is possible to prevent the measurement error of the water content ratio of the soil sample due to the amount of the input sample from increasing as described above.

According to the water content measuring method of the sample described in claim 5, the same action as the water content measuring method of the sample described in claim 4 is exerted, and in filling the sample in the cylindrical container, Since the sample is crushed with a load that does not exceed a certain value and filled in the cylindrical container in multiple times, the filling state of the sample in the cylindrical container can be controlled.

Therefore, it is possible to prevent the measurement error of the water content ratio due to the non-uniform filling of the sample.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

First, the structure will be described.

FIG. 1 is a diagram showing the construction of a sample water content ratio measuring apparatus 1 which is an embodiment of the present invention.

Referring to FIG. 1, a sample water content ratio measuring device 1
Is connected to the insulating cylindrical container 2 for containing the sample, the two electrode plates 31, 32 provided facing the inner peripheral surface 21 of the cylindrical container 2, and the both electrode plates 31, 32. An alternating current power source 4 for supplying a constant alternating current to the soil sample placed in the cylindrical container 2 and a potentiometer 5 connected to the two electrode plates 31, 32 in series with the alternating current power source 4.

The cylindrical container 2 is, for example, a plastic transparent container. The electrode plates 31 and 32 are the cylindrical container 2
Is a plate-like electrode formed from the inlet to the bottom of the. The inner peripheral surface 21 of the cylindrical container 2 has electrode plates 31, 32.
The inner surface 2 has a height of one half and a height of two thirds.
Line-shaped markings 61, 62 that go around the circumference of 1
Is given. This is a standard for determining the amount of the sample contained in the cylindrical container 2.

FIG. 2 is a vertical sectional view of the cylindrical container 2 as described above, and FIG. 3 is a view taken along the line AA of FIG. In FIG. 2, reference numeral 7 is a connection line between the power source 4, the potentiometer 5, and the electrode plates 31 and 32.

Next, the operation of this embodiment will be described.

First, the water content measuring device 1 is prepared,
The soil sample is filled in the cylindrical container 2. When the sample is filled in the cylindrical container 2, the markings 61 and 62 are used as a guide, and the sample is compacted with a load that does not exceed a certain value, and the sample is filled a plurality of times (for example, four times). The sample can be compacted by inserting a cylindrical compaction rod having a cross-sectional diameter equal to the inner diameter of the cylindrical container 2 into the cylindrical container 2. In addition, a load sensor is provided on the tamping rod to detect the load applied to the tamping rod when the sample is tamped, and when the detected load exceeds a predetermined value,
If it is notified by light or sound, or if the load is not transmitted to the sample, it becomes easy to compact the sample with a load that does not exceed a certain value.

After the cylindrical container 2 is filled with the sample in this way, a constant current is applied to the sample in the cylindrical container 2 by the power source 5 to measure the potential difference between the electrode plates 31 and 32 with the potentiometer 5. . The current flowing through the sample is constant, and the electrode plate 31,
Since the potential difference between the electrodes 32 is obtained, the resistance value of the sample between the electrode plates 31 and 32 can be obtained.

By comparing the obtained resistance value with the data showing the correlation between the resistance value of the sample and the water content ratio of the sample, which is obtained in advance by the same method as described above using the same apparatus as above, , The water content of the sample can be determined.

According to this embodiment, it is not necessary to spend one day to dry the sample in a drying oven or the like as in the conventional case, and the water content of the soil sample can be immediately measured on site. You can ask. Moreover, the water content measuring device 1 has a simple device configuration as described above, and does not require a conventional drying furnace, so that the water content of the soil sample can be obtained with a simple device.

It is also possible to construct the water content ratio measuring device 1 by using the power source 5 as a DC power source, but since the power source 5 is an AC power source in this embodiment, the electric field applied from the electrode plates 31, 32 to the sample is reduced. The polarization of the sample can be prevented by reversing the direction, and an error in measuring the resistance value of the sample is unlikely to occur.
Therefore, the measurement error of the water content ratio of the soil sample due to the polarization of the sample can be suppressed.

Further, since the container 2 has a cylindrical shape, the container 2 is relatively difficult to be deformed even if it is formed thin, and the spread of the electric field from the voltage applying electrode is kept constant, and the resistance value of the sample is kept. The measurement result of can be stabilized. Therefore, it is possible to prevent the measurement error of the water content ratio of the soil sample due to the nonuniform electric field.

Moreover, the amount of the sample in the container 2 is controlled by introducing the sample into the container 2 using the markings 61 and 62 provided on the container 2 as a guide, and the resistance of the sample due to the amount of the sample to be injected is controlled. The measurement error of the value can be suppressed. Further, since the container 2 is transparent, the container 2
By controlling the amount of the sample in the container 2 while visually observing the inside of the container 2 from the outside, it is possible to prevent the measurement error of the resistance value of the sample due to the amount of the input sample from occurring. Therefore, it is possible to prevent an error in measurement of the water content ratio of the soil sample due to the amount of the input sample.

When filling the container 2 with the sample, the sample 2 is filled into the container 2 in a plurality of times while being compacted with a load that does not exceed a certain value, so that the filling state of the sample in the container 2 is controlled. it can. Therefore, it is possible to prevent the measurement error of the water content ratio due to the non-uniform filling state of the sample.

[0041]

According to the apparatus for measuring water content of a sample described in claim 1, it is not necessary to spend one day to dry the sample in a drying oven or the like in order to bring the sample into an absolutely dry state as in the conventional case. Instead, the water content of soil samples can be immediately obtained on-site. Moreover, the apparatus configuration of the present invention is simple as described above, and does not require a conventional drying furnace or the like, so that the water content of the soil sample can be obtained with a simple apparatus.

Further, it is possible to prevent the measurement error of the water content ratio of the soil sample due to the non-constant electric field.

Further, it is possible to prevent the measurement error of the water content ratio of the soil sample due to the amount of the input sample from increasing.

According to the water content measuring apparatus for the sample described in claim 2, the same effect as the water content measuring apparatus for the sample described in claim 1 can be obtained, and the water content of the soil sample can be measured by the polarization of the sample. It is possible to make an error less likely to occur.

According to the water content measuring apparatus for the sample described in claim 3, the same effect as the water content measuring apparatus for the sample described in claim 1 or 2 can be obtained, and the soil sample by the amount of the input sample can be obtained. The measurement error of the water content ratio can be suppressed.

According to the method for measuring the water content of a sample described in claim 4, it is not necessary to spend one day to dry the sample in a drying oven or the like as in the conventional case, The water content of soil samples can be immediately obtained on-site. Moreover, the structure of the measuring device used is simple as described above, and since the conventional drying furnace is not required, the water content of the soil sample can be obtained with a simple device.

If the measuring device is the one described in claim 2, it is possible to prevent the measurement error of the water content ratio of the soil sample due to the polarization of the sample as described above. If it is one, it is possible to prevent the measurement error of the water content ratio of the soil sample due to the amount of the input sample from increasing as described above.

According to the method for measuring the water content ratio of the sample described in claim 5, the same effect as that of the method for measuring the water content ratio of the sample described in claim 4 can be obtained, and the water content ratio due to the non-uniform filling state of the sample. It is possible to prevent the measurement error of 1.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a sample water content ratio measuring apparatus according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a sample water content ratio measuring apparatus according to an embodiment of the present invention.

FIG. 3 is a view taken along the line AA in FIG. 2 of the apparatus for measuring the water content ratio of the sample according to the embodiment of the present invention.

[Explanation of symbols]

 1 Water content measuring device for sample 2 Cylindrical container 31, 32 Electrode plate 41, 42 AC power supply 5 Potentiometer 61, 62 Marking

Claims (5)

[Claims] 1. An insulative transparent cylindrical container for containing a sample, two electrodes provided to face the inner peripheral surface of the cylindrical container, and the cylindrical container connected to both electrodes. An apparatus for measuring a water content ratio of a sample, comprising: a power source for supplying a constant current to the sample therein; and a potentiometer connected to the electrodes in series with the power source. 2. The sample water content ratio measuring device according to claim 1, wherein the power source is an AC power source. 3. The water content measurement of the sample according to claim 1 or 2, wherein the cylindrical container is provided with a mark serving as a guide for judging the amount of the sample contained in the container. apparatus. 4. A sample water content ratio measuring apparatus according to claim 1 is prepared, and the cylindrical container is filled with the sample. A constant current is applied to the sample to measure the potential difference between the two electrodes with the potentiometer to determine the resistance value of the sample, and the resistance value of the sample and the water content ratio of the sample are determined in advance by the same means. A method for measuring the water content ratio of a sample, in which the water content ratio of the sample is determined by comparing the data indicating the correlation with the resistance value obtained this time. 5. The method according to claim 4, wherein when the sample is filled in the cylindrical container, the sample is filled in the cylindrical container in a plurality of times while being compacted with a load that does not exceed a certain value. Method for measuring water content of sample.