JP2016191582A - Method for measuring moisture content ratio and moisture content percentage of soil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the moisture content ratio and moisture content percentage of soil to be measured easily in the scene of soil sampling.SOLUTION: A soil sample weighing A grams is put into a sucrose aqueous solution of B% in sucrose concentration and C grams in weight, and the sugar content of the stirred solution is measured with a saccharimeter or a refractometer. On the basis of the measured sugar content D%, the X-gram weight of water in the soil is calculated by the following formula (1), and further the moisture content ratio Y% or the moisture content percentage Z% of the soil is calculated by the following formulas (2) and (3). X={(B×C)/D}-C ...(1) Y={X/(A-X)}×100 ...(2) Z=(X/A)×100 ...(3)SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technical field of a method for measuring moisture content and moisture content of soil.

In general, knowing the proportion of water in the soil (water content, water content) is important for research on impacts on vegetation growth, groundwater behavior, analysis of slope failure mechanisms including embankments, and prediction of flood occurrence. Therefore, it is one of the important factors, and as a result, the JIS A 1203 “Soil moisture content test method” is standardized as a Japanese Industrial Standard. This is a so-called furnace drying method in which the moisture content of soil is determined based on measuring the weight of the collected soil and the weight after drying the soil in the furnace. However, soil drying requires a long drying time of 18 to 24 hours in a constant temperature drying furnace maintained at 110 ± 5 ° C., and not only is the workability poor, but the constant temperature drying furnace is used for soil sampling. The collected soil must be brought back to a laboratory equipped with a high-temperature drying furnace and dried, and brought to the laboratory while maintaining the moisture content at the time of collection. Therefore, there is a problem that special techniques and operations are necessary and time-consuming.
On the other hand, as a method for measuring soil moisture, tensiometer method (see Patent Document 1), dielectric method (see Patent Document 2), electric resistance method (see Patent Document 3), heat conduction method (see Patent Document 4), electromagnetic wave Many methods such as the method (see Patent Document 5) are known.

Japanese Patent Laid-Open No. 7-244040 Japanese Patent No. 2913022 JP 2004-77353 A JP 2006-194421 A JP 2009-98018 A

  However, among the above-mentioned conventional ones, Patent Documents 1, 2, and 5 have a problem that the apparatus itself is large and must be embedded in soil, resulting in poor workability. On the other hand, Patent Documents 3 and 4 have the advantage that the sensor itself can be reduced in size, but the previously collected soil is dried to measure the electrical resistance value and thermal conductivity in the dried soil, and then the dried It is necessary to create a calibration curve by measuring the electrical resistance and thermal conductivity of some of the soil impregnated with the required amount of water, but the same calibration curve may not be used when the soil is different. Therefore, there is a problem that these calibration curves must be prepared for each measurement site having different soil properties, which is troublesome and complicated. Further, in Patent Documents 1 to 5, the point that the soil must be brought into the laboratory while maintaining the water content ratio at the time of collection is still unsolved, and there is a problem to be solved by the present invention.

The present invention was created with the object of solving these problems in view of the above-mentioned circumstances, and the invention of claim 1 is a method for measuring the moisture content of soil, and the collected weight A Gram soil is put into a sucrose aqueous solution with a sucrose concentration (weight% concentration) B% and a weight C gram, and after stirring, the sugar content of the solution obtained by filtration is measured with a saccharimeter or a refractometer. Based on the sugar content D%, the weight X gram of water in the soil of the collected weight A gram was calculated using the following formula (1), and the water content ratio Y% of the soil was further calculated using the following formula (2). It is a method for measuring the moisture content of soil, characterized in that it is calculated.
X = {(B × C) / D} −C (1)
Y = {X / (A−X)} × 100 (2)
The invention of claim 2 is a method for measuring the water content ratio of soil, wherein the collected soil having a weight of A gram is placed in a sucrose aqueous solution having a sucrose concentration (weight% concentration) of B% and a weight of C gram and stirred. The sugar content of the solution obtained above was measured with a saccharimeter or a refractometer, and based on the measured sugar content D%, the weight X grams of water in the soil of the weight A gram collected using the following formula (1) was calculated. The soil moisture content measurement method is characterized in that the soil moisture content Y% is calculated using the following formula (2).
X = {(B × C) / D} −C (1)
Y = {X / (A−X)} × 100 (2)
The invention of claim 3 is that in claim 1 or 2, the sugar content of the solution measured by a saccharimeter or a refractometer is corrected by a blank test using water and soil used to prepare a sucrose aqueous solution. This is a characteristic method for measuring the moisture content of soil.
The invention according to claim 4 is a method for measuring the moisture content of soil, wherein the collected soil having a weight of A gram is put into a sucrose aqueous solution having a sucrose concentration (weight% concentration) of B% and a weight of C gram, followed by stirring. The sugar content of the solution obtained by filtration is measured with a saccharimeter or a refractometer, and the weight of water in the soil of the weight A gram collected using the following formula (1) based on the measured sugar content D% The soil moisture content measurement method is characterized in that X gram is calculated and the soil moisture content Z% is calculated using the following equation (3).
X = {(B × C) / D} −C (1)
Z = (X / A) × 100 (3)
The invention of claim 5 is a method for measuring the moisture content of soil, wherein the collected soil having a weight of A gram is placed in a sucrose aqueous solution having a sucrose concentration (weight% concentration) of B% and a weight of C gram and stirred. The sugar content of the solution obtained above was measured with a saccharimeter or a refractometer, and based on the measured sugar content D%, the weight X grams of water in the soil of the weight A gram collected using the following formula (1) was calculated. The soil moisture content measurement method is characterized in that the soil moisture content Z% is calculated using the following equation (3).
X = {(B × C) / D} −C (1)
Z = (X / A) × 100 (3)
The invention of claim 6 is the method according to claim 4 or 5, wherein the sugar content of the solution measured by a saccharimeter or a refractometer is corrected by a blank test using water and soil used for preparing a sucrose aqueous solution. This is a characteristic method for measuring the moisture content of soil.

By setting it as invention of Claim 1, 2, the moisture content of a soil can be calculated | required easily also in the soil collection field.
By setting it as invention of Claim 3, a more exact water content ratio can be calculated | required.
By setting it as invention of Claim 4, 5, the moisture content of a soil can be calculated | required easily also in the soil collection field.
By setting it as invention of Claim 6, a more exact water content ratio can be calculated | required.

It is a flowchart which shows the measuring method of the moisture content of a soil, and a moisture content.

Embodiments of the present invention will be described below.
In this embodiment, a saccharimeter is used to measure the saccharide content, but the saccharose aqueous solution (Brix) and the refractive index can be easily converted using a conversion table or the like. You may make it measure sugar content by measuring a refractive index and converting this measured refractive index into sugar content. That is, the measurement of the sugar content in the present invention includes not only the case where the sugar content is directly measured by a saccharimeter, but also the case where the refractive index is measured by a refractometer and the measured refractive index is converted to a sugar content.
In the present invention, a saccharimeter (refractive saccharimeter) for measuring the sugar content (Brix) of an aqueous solution with the refractive index of the sucrose aqueous solution as a reference value, or a refractometer for measuring the refractive index of an aqueous solution is widely known. The sugar content of the aqueous sucrose solution measured by such a sugar content meter or the sugar content of the aqueous solution of sucrose obtained by converting the refractive index measured by a refractometer into sugar content is determined by the sucrose concentration (weight) of the aqueous solution of sucrose. % Sucrose concentration and refractometer, it is possible to measure the sucrose concentration of sucrose aqueous solution easily and accurately using a saccharimeter or refractometer, and try to measure the water content ratio and water content of the soil. Is.
Sucrose (sucrose) used for this measurement has a solubility in water of 211.5 g / 100 mL (20 ° C.) and is easily dissolved, and is easily dissolved in moisture in the soil. In addition, since sucrose is harmless to the human body and the natural environment, even if the sucrose aqueous solution is discarded at the measurement site after measurement, there is no environmental problem.
Furthermore, in the present embodiment, when measuring the water content ratio and moisture content of the soil, the sugar content measured by the saccharimeter or the saccharimeter is measured by a blank test using the water and soil used to prepare the sucrose aqueous solution. to correct. As a result, even if the water or soil used to prepare the aqueous sucrose solution contains a substance that affects the measured value of sugar content, the water content ratio and water content of the soil can be accurately determined regardless of the presence or absence of the substance. Can be measured. In the following description, all sucrose concentrations are weight% concentrations.

FIG. 1 is a flowchart showing a procedure for measuring the moisture content Y% or the moisture content Z% of the soil. First, a soil sample having a weight of A gram is collected on site. Then, the collected soil sample having a weight of A gram is put into a sucrose aqueous solution having a sucrose concentration of B% and a weight of C gram, and is stirred and filtered. In this case, the sucrose aqueous solution may be brought to the site. However, locally procured water (ground water, well water, river water, spring water, tap water, etc.) is water that can be procured locally. In addition, an aqueous sucrose solution may be prepared on site using water that has not yet been adjusted. The sucrose concentration B% of the sucrose aqueous solution is appropriately determined (for example, sucrose concentration 10% to 60%) in view of the wet state of the soil. Moreover, as a filter at the time of filtering, what was manufactured with the material which water does not infiltrate is preferable, for example, the thing made from synthetic resin like glass, silicone, polytetrafluoroethylene, etc. are employ | adopted.
Next, the sugar content D% of the solution obtained by filtration after the stirring (this solution is hereinafter referred to as a sample solution) is measured with a saccharimeter. The sugar content can be measured using a commercially available general-purpose sugar content meter (refractive sugar content meter). In this case, if it is a portable type, it can be easily brought to the site and is convenient. Further, as described above, the refractive index may be measured by a refractometer instead of the saccharimeter, and the saccharide degree may be obtained from the refractive index.

Then, based on the measured sugar content D%, the weight X gram of water in the soil of the collected weight A gram is calculated using the following formula (1).
X = {(B × C) / D} −C (1)
In addition, when it is thought that the substance which affects the measured value of sugar content is contained in the water and soil used for the preparation of the sucrose aqueous solution (for example, the unadjusted ingredients procured locally for the preparation of the sucrose aqueous solution) In the case of using water), as will be described later, the corrected sugar content Dh is used instead of the sugar content D% measured by the sugar content meter.
Further, based on the weight X grams of water in the soil calculated by the above formula (1), using the following formula (2), the moisture content Y% of the collected soil ((weight of water in soil / in soil) The dry soil weight) × 100%) is calculated. Alternatively, the moisture content Z% ((weight of water in soil / weight of soil) × 100%) of the collected soil is calculated using the following formula (3).
Y = {X / (A−X)} × 100 (2)
Z = (X / A) × 100 (3)

Here, in the above formulas (1), (2), (3) and formulas (4), (5), (6) described later,
A: Weight of collected soil (gram)
B: Sucrose concentration in sucrose aqueous solution (%)
C: Weight of sucrose aqueous solution (gram)
D: Sugar content (%) of sample solution
E: Weight of sucrose in sucrose aqueous solution (gram)
F: Sucrose concentration of sample solution (%)
X: Weight of water in the soil (gram)
Y: Soil moisture content (%)
Z: Moisture content of soil (%)
It is.

Specifically, for example, a soil sample of 15 grams is put in a 50 mL plastic test tube or a container such as a bag, and 15 grams of a sucrose aqueous solution having a sucrose concentration of 50% is put in this sample and shaken (for example, 2 The sugar content of the sample solution obtained by filtering this solution (for example, a filter having a pore diameter of 0.45 μm) is measured with a saccharimeter, and the above formula (1) is used based on the measured sugar content D%. The weight X gram of water in the collected soil is calculated, and the water content ratio Y% or the water content Z% of the soil sampled is calculated using the formula (2) or (3).
Note that filtration can be omitted when the aqueous solution of sucrose and the solution obtained after shaking are low, such as when the soil sample contains a small amount of clay, and filtration is omitted for most soil samples. It does not matter.

The formula (1) is derived as follows.
First, a weight E gram of sucrose in a sucrose aqueous solution having a sucrose concentration of B% and a weight C gram is represented by the following formula (4).
E = B × C / 100 (4)
On the other hand, the sample solution obtained by stirring and filtering the soil and the aqueous sucrose solution is in a state in which the sucrose concentration of the aqueous sucrose solution is diluted with water contained in the soil, and the sucrose concentration F % Is represented by the following formula (5).
F = {E / (C + X)} × 100 (5)
Here, since the sugar content measured by the sugar content meter is a value indicating the sucrose concentration, the sugar content D% of the sample solution is equal to the sucrose concentration F% of the sample solution (F = D), and the equation (5) When F is replaced with D, the following equation (6) is established.
D = {E / (C + X)} × 100 (6)
Then, by substituting the right side of Expression (4) for E in Expression (6) and rearranging, Expression (1) is derived.
Further, X calculated by the formula (1) is the weight of water in the soil, and the weight A gram of the soil is known from the measurement. Therefore, the water content of the soil is calculated using the formulas (2) and (3). The ratio Y% and the moisture content Z% can be calculated.

  By the way, in calculating the water content ratio and water content of the soil using the above formulas (1), (2), and (3), in order to establish the formula (6) for deriving the formula (1), It is assumed that the sugar content D% of the sample solution measured by the above is equal to the sucrose concentration F% of the sample solution. Therefore, if the water or soil used to make the aqueous sucrose solution does not contain substances that affect the measured value of sugar content, or if they are contained, they are in trace amounts and within the error range. No problem, but if there is a trace amount of substances that affect the measured sugar content of the sample solution, the sugar content of the sample solution measured by the saccharimeter is measured to be greater than the sucrose concentration of the actual sample solution. As a result, accurate moisture content and moisture content may not be calculated. Therefore, in order to cope with this, in the present embodiment, the value of the sugar content of the sample solution measured with a saccharimeter is corrected by a blank test.

When the sugar content of the sample solution is corrected by the blank test, the weight of A gram of soil is the same as the water used for the preparation of the sucrose aqueous solution having a sucrose concentration of B% and a weight of C gram (weight ( C × (100-B) / 100) grams), and after stirring, the sugar content of the water obtained by filtration is measured, and the measured sugar content E% is used as a blank. Then, as shown in the following formula (7), the blank E% is subtracted from the sugar content D% of the measured sample solution, and the reduced value is used as the corrected sugar content Dh% of the sample solution.
Dh = DE (7)
Then, as shown in the following formula (8), the weight X gram of water in the soil is calculated using the corrected sugar level Dh% instead of the sugar level D% of the sample solution in the formula (1).
X = {(B × C) / Dh} −C (8)
Furthermore, using the value of X calculated by the above equation (8), the water content ratio Y% and the water content Z% in the soil are calculated by the above equations (2) and (3).
Here, in the above formulas (7) and (8),
B: Sucrose concentration in sucrose aqueous solution (%)
C: Weight of sucrose aqueous solution (gram)
D: Sugar content (%) of sample solution
Dh: Corrected sugar content (%) of the sample solution
E: Blank (%)
X: Weight of water in the soil (gram)
It is.
And, by correcting the sugar content value of the sample solution measured with the saccharimeter by the blank test in this way, substances that affect the measured value of the sugar content of the sample solution in the water or soil used to prepare the aqueous sucrose solution Even if it is contained, the moisture content and moisture content of the soil can be accurately measured without worrying about the presence or absence of the substance.

In the case where the present invention has been carried out in this manner, the collected weight A gram of soil is put into a sucrose aqueous solution having a sucrose concentration of B% and a weight C gram, and after stirring, the sugar content of the obtained solution is filtered. Measured with a saccharimeter or a refractometer, and based on the measured sugar content D%, the weight (g) of water in the soil of the collected weight (A gram) was calculated using the formula (1). 2) Since the moisture content Y% and moisture content X% in the soil are calculated using (3), the moisture content and moisture content in the soil can be reduced in a short time even at the soil sampling site. You can easily ask for it. Therefore, it is not necessary to bring the soil to the laboratory while maintaining the moisture content and moisture content at the time of sampling, and it is no longer necessary to create laborious work and calibration curves as in the past. The efficiency of the measurement work can be greatly improved.
In this case, as described above, the filtering operation can be omitted in some cases.
In addition, the measurement of the sugar content includes not only the case where the sugar content is directly measured by a sugar content meter, but also the case where the refractive index is measured by a refractometer and the measured refractive index is converted into the sugar content as described above. is there.
In addition, since sucrose is harmless to the human body and the natural environment, there is no problem of pollution even if it is discarded at the collection site after measurement. It is easy to procure and manage.

  Furthermore, in this, the sugar content D% of the solution measured by a saccharimeter or a refractometer is corrected by a blank test using water and soil used for the preparation of the sucrose aqueous solution, and based on the corrected saccharide content Dh. By calculating the water content and water content, even if the water or soil used to prepare the sucrose aqueous solution contains substances that affect the measured sugar content, the presence or absence of the substances should be considered. In addition, the water content ratio and water content of the soil can be measured more accurately.

The present invention can be used when measuring the moisture content and moisture content in soil.

Claims (6)

A method for measuring the water content ratio of soil, in which a collected weight of gram of soil is placed in a sucrose aqueous solution having a sucrose concentration (weight% concentration) of B% and a weight of C gram, stirred and then filtered. The sugar content is measured by a sugar content meter or a refractometer, and based on the measured sugar content D%, the weight X grams of water in the soil of the collected weight A grams is calculated using the following formula (1). A method for measuring the moisture content of soil, wherein the moisture content Y% of the soil is calculated using the following formula (2).
X = {(B × C) / D} −C (1)
Y = {X / (A−X)} × 100 (2) A method for measuring the moisture content of soil, wherein the collected weight A gram of soil is placed in a sucrose aqueous solution having a sucrose concentration (weight% concentration) B% and a weight C gram, and the sugar content of the solution obtained by stirring is determined. Measured with a saccharimeter or a refractometer, and based on the measured sugar content D%, the weight X gram of water in the soil of the collected weight A gram was calculated using the following formula (1). A method for measuring the moisture content of soil, wherein the moisture content Y% of the soil is calculated using 2).
X = {(B × C) / D} −C (1)
Y = {X / (A−X)} × 100 (2)   The water content ratio of the soil according to claim 1 or 2, wherein the sugar content of the solution measured by a saccharimeter or a refractometer is corrected by a blank test using water and soil used for preparing a sucrose aqueous solution. Measuring method. A method for measuring the moisture content of soil, in which a sample of A gram of soil collected is placed in an aqueous sucrose solution having a sucrose concentration (wt% concentration) of B% and a weight of C gram, stirred and then filtered. The sugar content is measured by a sugar content meter or a refractometer, and based on the measured sugar content D%, the weight X grams of water in the soil of the collected weight A grams is calculated using the following formula (1). A method for measuring the moisture content of soil, wherein the moisture content Z% of the soil is calculated using the following formula (3).
X = {(B × C) / D} −C (1)
Z = (X / A) × 100 (3) A method for measuring the moisture content of soil, wherein the collected weight A gram of soil is placed in a sucrose aqueous solution having a sucrose concentration (weight% concentration) B% and a weight C gram, and the sugar content of the solution obtained by stirring is determined. Measured with a saccharimeter or a refractometer, and based on the measured sugar content D%, the weight X gram of water in the soil of the collected weight A gram was calculated using the following formula (1). A method for measuring the moisture content of soil, characterized in that the moisture content Z% of the soil is calculated using 3).
X = {(B × C) / D} −C (1)
Z = (X / A) × 100 (3)   The moisture content of the soil according to claim 4 or 5, wherein the sugar content of the solution measured by a saccharimeter or a refractometer is corrected by a blank test using water and soil used for preparing the sucrose aqueous solution. Measuring method.

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