JP2011095046A - Method for checking/testing gas permeability of gas-permeable filler material and gas permeability checking/testing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of checking/testing for rapidly checking whether filler materials of various components have appropriate gas permeability based on standard indices by establishing the indices for standardly evaluating the gas permeability of filler materials. <P>SOLUTION: This testing device 1 includes: an outer frame 10 internally supporting a columnar test piece M formed of a filler material which is a testing object, coated with an airtight resin on its side face, and having a set height (L) and a constant cross-section area (A); a support 11 supporting an outlet end 12a of an air inflow pipe 12 causing air to flow thereinto on one side (m1) of an opened end face of the columnar test piece M while supporting the outer frame 10; a flow sensor 20 measuring the flow of air flowing through the air inflow pipe 12; a pressure sensor 21 measuring pressure of air flowing into the inflow pipe 12; and an air supply device 30 causing air to flow into the inflow pipe 12 at a set constant pressure. The testing device 1 is used to find an air permeability coefficient K=(L/h)×äQ/(A×t)} by using pressure (h) and flow (Q) measured at set time (measurement time t). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an air permeability confirmation test method and an air permeability confirmation test apparatus for an air permeable stuffing material such as air mortar.

  For example, a filling material such as air mortar used when piping a gas conduit in a tunnel is required to have good air permeability so that a leaked gas from the gas conduit can be detected quickly. However, an index for standard evaluation of the air permeability of such filling materials has not been established, and a standard index is used to determine whether or not appropriate filling properties are provided for the filling materials of various components. There is a need for a test method that can be quickly confirmed based on this.

  In Patent Document 1 below, a specimen having a diameter of 5 cm and a height of 10 cm is taken from the cellular concrete of the construction example and cured for 28 days in a thermostatic bath at 20 ° C. and a humidity of 90% or more. It describes that the air permeability coefficient is obtained by measuring the flow rate when the inflow amount and the outflow amount are equalized by applying air pressure.

JP 2005-60188, page 5, lines 40-47

  In such a conventional technique, there is a problem that a standard evaluation cannot be performed due to a difference in evaluation value due to a formation dimension error of the specimen, and there is a trouble in adjusting the inflow amount and the outflow amount to be equal. Therefore, there is a problem that a quick evaluation cannot be performed.

  This invention makes it an example of a subject to cope with such a problem. In other words, we established an index for standard evaluation of the air permeability of filling materials, and quickly confirmed whether or not they have proper air permeability for various filling materials based on the standard indicators It is an object of the present invention to provide a confirmation test method and a confirmation test apparatus that can be performed.

  In order to achieve such an object, an air permeability confirmation test method and an air permeability confirmation test device for an air permeable filling material according to the present invention have at least the following configurations.

A columnar specimen having a set height (L) and a constant cross-sectional area (A) in which an airtight resin is applied to the side surface is formed by the filling material to be tested, and constant from one of the open end faces of the columnar specimen. The pressure (h) and the flow rate (Q) of the inflowing air are measured for a set time (t) while the pressure air is introduced and the other end surface is opened to the atmosphere, and the air permeability coefficient is calculated by the following equation (1). A method for confirming air permeability of an air permeable filling material, characterized in that K is obtained.
K = (L / h) × {Q / (A · t)} (1)
here,
L: Height of the columnar specimen A: Cross-sectional area of the columnar specimen h: Pressure of air flowing in Q: Flow rate of air flowing in t: Measurement time

A columnar specimen having a set height (L) and a constant cross-sectional area (A) in which an airtight resin is applied to the side surface is formed by the filling material to be tested, and constant from one of the open end faces of the columnar specimen. Measure the set time (t) of the pressure (h) and the flow rate (Q) of the air that flows into the other end of the end face while letting the other side of the air into the atmosphere. A linear regression through the origin is performed with the relationship between the pressure gradient i and the flow velocity v by the measured flow rate (Q), and the pressure gradient and the flow velocity straight line are within a range of the pressure gradient in which a significant linear approximation is obtained. An air permeability confirmation test method for an air permeable filling material, wherein the air permeability coefficient K of a columnar specimen is determined by a regression coefficient in a regression equation.
However,
L: Height of the columnar specimen A: Cross-sectional area of the columnar specimen h: Inflowing air pressure Q: Inflowing air flow t: Measurement time i: Pressure gradient v: Flow velocity Q / (A · t), i = h / L

  One of an outer frame that supports a columnar specimen having a set height and a constant cross-sectional area, which is formed of a filling material to be tested and has an airtight resin applied to the side surface, and an open end face of the columnar specimen. Supporting a discharge end of an air inflow pipe for allowing air to flow into one of the end faces and supporting the outer frame, a flow rate sensor for measuring a flow rate of air flowing through the air inflow pipe, and the air Air permeability of the air permeable filling material, comprising: a pressure sensor that measures the pressure of air flowing into the inflow pipe; and an air supply device that flows air into the air inflow pipe at a set constant pressure. Confirmation test equipment.

  According to such characteristics, an index for standard evaluation of the air permeability of the filling material is established, and whether or not it has appropriate air permeability for the filling material of various components is based on the standard index. Can be confirmed quickly.

It is explanatory drawing which shows the air permeability confirmation test apparatus which concerns on one Embodiment of this invention. It is explanatory drawing explaining the application range of the Darcy law in an air permeability confirmation test. It is explanatory drawing (the graph which showed the regression line of the pressure gradient i and the flow velocity v) explaining the Example of this invention. It is explanatory drawing (the graph which showed the regression line of the pressure gradient i and the flow velocity v) explaining the Example of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view showing an air permeability confirmation test apparatus according to an embodiment of the present invention. The air permeability confirmation test apparatus 1 according to the embodiment of the present invention is a test apparatus for confirming air permeability with respect to a columnar specimen M formed of a filling material to be tested. Here, the columnar specimen M is a specimen formed in a columnar shape having a constant cross section such as a circle, an ellipse, a rectangle, etc., and a pair of end faces are opened and an airtight resin G1 is applied to the side surfaces. . As the airtight resin G1 used here, a high-viscosity resin with little impregnation into the specimen is suitable, and a high-viscosity epoxy resin is suitable in consideration of ease of application and ensuring airtightness.

  The air permeability confirmation test apparatus 1 includes an outer frame 10, a support base 11, an air inflow pipe 12, a flow sensor 20, a pressure sensor 21, an air supply device 30, and the like. The outer frame 10 is a member that supports the columnar specimen M described above, and the shape and material thereof are not particularly limited. For example, a transparent acrylic resin plate is used to surround the columnar specimen M. Thus, the test can be performed while observing the state of the columnar specimen M. In order to support the columnar specimen M inside the outer frame 10, for example, as shown in the drawing, the inside of the outer frame 10 is filled with an airtight resin G2 having a predetermined height. In this case, an epoxy resin can also be used for the airtight resin G2. The outer space of the columnar specimen M is filled with an airtight resin G2 so that both end faces m1 and m2 of the columnar specimen M are opened. The outer frame 10 may be omitted as long as the columnar specimen M can be supported on the support base 11 described later by some other means.

  The support base 11 supports the discharge end 12a of the air inflow pipe 12 that allows air to flow into one of the open end faces (m1) of the columnar specimen M toward one of the end faces (m1), and the outer frame 10 It is something to support. In the illustrated example, the end surface m1 of the columnar specimen M supported inside the outer frame 10 faces the support base 11, and the discharge end 12a of the air inflow pipe 12 is brought into contact with the end surface m1. ing.

  The air inflow pipe 12 is an inflow path for allowing air to flow into the columnar specimen M, and a flow sensor 20 is disposed in the middle of the inflow path, and a pressure sensor 21 is disposed at an end thereof. Moreover, you may make it the structure which arrange | positions the valve | bulb 22 in the middle path | route as needed. The flow sensor 20 is for measuring the flow rate of air flowing through the air inflow pipe 12, and the pressure sensor 21 is for measuring the pressure of air flowing into the air inflow pipe 12.

  The air supply device 30 can flow air into the air inflow pipe 12 at a set constant pressure. In order to obtain a more standardized test result, the air supply device 30 can variably adjust the set pressure. It is preferable.

  Moreover, you may provide the cover member 13 in the edge part on the opposite side to the side supported by the support stand 11 in the outer frame 10 as needed. Since the end surface m2 of the columnar specimen M needs to be opened to the atmosphere, even when the lid member 13 is provided, it is necessary that the end of the outer frame 10 be not airtightly closed, and a predetermined air permeability is obtained. Is used.

  An air permeability confirmation test method according to an embodiment of the present invention using such an air permeability confirmation test apparatus 1 will be described below. The air permeability confirmation test method according to the embodiment of the present invention forms the columnar specimen M having the set height (L) and the constant cross-sectional area (A) as described above by using the filling material to be tested, and the columnar specimen. A constant pressure of air is introduced from one of the open end faces (m1) of M and the other end (m2) of the end face is opened to the atmosphere, and the pressure (h) and flow rate (Q) of the incoming air are set for a set time. (T) Measure and obtain the air permeability coefficient K by the following equation (1).

K = (L / h) × {Q / (A · t)} (1)
here,
L: Height of the columnar specimen A: Cross-sectional area of the columnar specimen h: Pressure of air flowing in Q: Flow rate of air flowing in t: Measurement time

Here, in order to set the unit of the air permeability coefficient K to cm / sec, the unit of the height L of the columnar specimen M is cm, and the unit of the cross-sectional area A of the columnar specimen M is cm ² . The unit of the pressure h of the incoming air is cm whose height is converted, the unit of the flow rate Q of the incoming air is cm ³ converted to a volumetric flow rate of 20 ° C. and 1 atm, and the measurement time t is sec.

More specifically, as shown in FIG. 1, a columnar specimen M is arranged on the support base 11, and the discharge end 12a of the air inflow pipe 12 is brought into contact with the end surface m1 of the columnar specimen M so that the air inflow The air tightness between the support base 11 and the outer periphery of the end face m1 is ensured so that all the air discharged from the pipe 12 flows into the columnar specimen M, the valve 22 is opened, and the air supply device 30 is operated. . Then, it is confirmed that the pressure h (cm) measured by the pressure sensor 21 constantly shows a constant set value, and the flow rate Q (cm ³ ) during a predetermined measurement time t (sec) is determined. Measurement is performed by the flow sensor 20. Then, from L (cm) and A (cm ² ) obtained from the specifications of the columnar specimen M and h (cm), Q (cm ³ ), and t (sec) obtained by measurement, from the formula (1) The air permeability coefficient K (cm / sec) is obtained.

  Expression (1) is an expression derived based on Darcy's law for determining the hydraulic conductivity at a constant pressure by treating air, which is originally a compressible fluid, as an incompressible fluid. In practice, since air is a compressive fluid, the relationship of formula (1) does not hold under all conditions, but the outer periphery of the columnar specimen M is covered with an airtight resin G1 to thereby form the inside of the columnar specimen M. By limiting the flow of air in a uniaxial direction and keeping the pressure of the incoming air constant, it is possible to obtain test conditions to which the Darcy law can be applied. That is, not only applying the Darcy law to the air permeability coefficient, but opening both end faces of the columnar specimen M and applying airtight resin to the side faces, and further, air at a constant pressure from one end face of the columnar specimen M. It is one of the features of the present invention that the test conditions for applying Darcy's law can be obtained by injecting the water and opening the other end surface to the atmosphere.

  Further, in order to obtain the air permeability characteristics of the columnar specimen M by applying Darcy's law, it is necessary to determine the applicable range of Darcy's law. When the flow velocity of air in the columnar specimen M is v (= Q / (A · t)) and the pressure gradient is i (= h / L), the relationship between the pressure gradient i and the flow velocity v is shown in FIG. As shown, assuming that Darcy's law holds, the relationship is a straight line a passing through the origin. However, when air, which is a compressible fluid, is used as the permeation medium, when the pressure gradient i increases, the relationship between the pressure gradient i and the flow velocity v deviates from the straight line a. For example, under the condition where the compressibility of air affects, the relationship between the pressure gradient i and the flow velocity v becomes a curve relationship as shown by the curve b in FIG. 2, and under the condition where the air flow transitions from laminar flow to turbulent flow, The relationship between the gradient i and the flow velocity v is a curve relationship like the curve c in FIG.

  Therefore, in order to obtain the air permeability characteristics of the columnar specimen M by applying Darcy's law, it is premised that the relationship between the pressure gradient i and the flow velocity v is a linear relationship passing through the origin. It is necessary to obtain the air permeability coefficient K using the formula (1) based on the measured value.

  In addition, a uniform air permeability coefficient K can be obtained by changing the pressure h and obtaining the relationship between the pressure gradient i and the flow velocity v based on the flow rates Q respectively measured for different pressures h. . That is, with the flow rate Q measured for each of the different pressures h, a linear regression through the origin is performed in the relationship between the pressure gradient i and the flow velocity v, and the pressure gradient is within a range of the pressure gradient i in which a significant linear approximation is obtained. A linear regression equation of i and flow velocity v is obtained, and the air permeability coefficient K of the columnar specimen M is determined by the regression coefficient in this linear regression equation.

The relationship between the pressure gradient i and the flow velocity v is v = K · i (K: air permeability coefficient) as long as Darcy's law can be applied. Using a plurality of sets of (i, v) data obtained from the measured values, linear regression of v = K · i is performed, and the measured data is selected so that the determination coefficient (correlation coefficient) R ² is closer to 1. . As described above, when the pressure gradient i increases, the factor that the relationship of (i, v) deviates from the straight line increases. Therefore, an upper limit of the pressure gradient i is determined, and within the range of the pressure gradient i, (i, v) The regression coefficient in the linear regression equation is obtained, and this regression coefficient is defined as the air permeability coefficient K of the columnar specimen. Range of pressure gradient i in that case, the linear regression equation of the coefficient of determination R ² is 0.90 or more, more preferably to select the measured value so that the 0.95 or more.

  The air permeability coefficient K thus determined is a standard value that is not affected by the size of the specimen and the length of the measurement time. Moreover, since it is only necessary to simply measure the state of the air flowing into the columnar specimen M, the measurement is simple, and it is possible to quickly evaluate the air permeability of the specimen.

  Since the outer periphery of the columnar specimen M is covered with the airtight resin G1, air leaking from the side surface of the columnar specimen M can be prevented, and a test result focusing only on the uniaxial permeability of the columnar specimen M is obtained. It is done. This makes it possible to suppress variations in measurement results due to differences in the shape of the columnar specimen M, and to perform more standardized air permeability evaluation. Furthermore, since the columnar specimen M is supported by filling the inside of the outer frame 10 with the airtight resin G2 having a predetermined height, it becomes a structure that facilitates ensuring the airtightness around the end surface m1 of the columnar specimen M, It becomes possible to obtain a more accurate measurement result.

  In the above description, the example of the test method using the illustrated air permeability confirmation test apparatus 1 has been described. However, the air permeability confirmation test method according to the embodiment of the present invention is not limited to the air permeability confirmation test apparatus as illustrated. If a pressure (h) and a flow rate (Q) equivalent to the case of using 1 can be measured, it can be implemented without using such a device.

  By adopting the air permeability confirmation test method according to the embodiment of the present invention, with respect to the filling material used when piping the gas conduit in the tunnel, the air permeability with respect to the filling materials of various components is accurately determined. And it can evaluate with high reproducibility. As a result, the quality of the filling material can be made uniform, and as a result, in the airtight test after piping, the holding time can be determined accurately and at low cost, and in the unlikely event that gas leaks from the piping However, gas can be detected efficiently. As described above, according to the embodiment of the present invention, it is possible to establish a standardized performance evaluation method in the filling method for tunnel piping.

  Below, the Example of the air permeability confirmation test method and the air permeability confirmation test apparatus of this invention is described. Here, air mortar was used as a test object, and the air permeability confirmation test using the above-described air permeability confirmation test apparatus was performed on the three specimens (specimen 1, specimen 2, specimen 3). Table 1 shows the test conditions. Table 2 shows the dimensions of each specimen.

[Test procedure]
(1) Shaping and installation of the specimen The specimen is shaped into a cylindrical shape with a diameter of 49.9 mm, and the end face is shaped so as to be smooth while maintaining parallelism in the vertical direction. After shaping, the specimen density is measured. Apply a high-viscosity epoxy adhesive to the side of the shaped specimen. After the high-viscosity epoxy adhesive is cured, the specimen is placed on the support base 11 of the air permeability confirmation test apparatus 1 shown in FIG. 1, and the low-viscosity epoxy adhesive is placed as the airtight resin G2 and the specimen is placed on the support base 11. Adhere.

(2) Air Permeation Measurement The air supply device 30 is operated and pressurized until the measured value of the pressure sensor 21 reaches an arbitrary pressure, and the flow rate sensor 20 measures the flow rate per minute. The flow rate is measured by the flow rate sensor 20 sequentially by changing the pressure in several steps.

(3) Calculation of air permeability coefficient Based on the measurement result, the air permeability coefficient K corresponding to each pressure is obtained for each specimen by the above-described equation (1). Here, if the measurement value of the pressure sensor is P, h (cm) = P (kPa) /0.098 in the equation (1).
[Test results]
Tables 3 to 5 show the test results of the specimens 1 to 3.

[Organization of test results]
The relationship of equation (1) is based on the premise that the Darcy law that holds for a one-dimensional flow of an incompressible fluid in a porous medium also holds when air is used as the permeation medium. However, when air, which is a compressible fluid, is used as a permeation medium, the conditions under which the Darcy law can be applied are limited by the compressibility and the transition from laminar flow to turbulent flow.

  In the test results shown in Tables 3 to 5, the calculated value of the air permeability coefficient k (excluding the measured value 0) is 0.600 to 1.233 (cm / s) for the specimen 1, and is 0.00 for the specimen 2. 530 to 1.173 (cm / s), which is a large variation of 0.747 to 1.490 (cm / s) in the specimen 3, and a uniform value for evaluating the transmission characteristics of the specimen. It is not. This means that the range of pressure change exceeds the range where Darcy's law can be applied. In a range where the Darcy law can be applied, the relationship between the pressure gradient i (= h / L) and the flow velocity v (= Q / (A · t)) is on a straight line passing through the origin (v = k · i).

A graph of a regression line (y = k · x) passing through the origins of i (x) and v (y) obtained from the test results of Tables 3 to 5 is shown in FIG. In the linear regression equation shown in FIG. 3, the specimen 1 is y = 0.6734 · x (R ² = 0.8799), the specimen 2 is y = 0.60223 · x (R ² = 0.882), The specimen 3 is y = 0.8486 · x (R ² = 0.8696), but the determination coefficient (correlation coefficient) R ² is not so high. It can be seen that the higher the pressure gradient i, the lower the rate of increase of the flow velocity v with respect to the rise of the pressure gradient i and the linear relationship is broken, and this is affected by the transition from laminar flow to turbulent flow. it is conceivable that.

On the other hand, FIG. 4 shows an analysis result obtained by performing linear regression after removing a measurement value that is easily affected by the transition from laminar flow to turbulent flow (pressure gradient i is high). The linear regression equation at this time is as follows: Specimen 1 is y = 0.9958 · x (R ² = 0.9357), Specimen 2 is y = 0.9176 · x (R ² = 0.9402), Specimen 3 is y = 0.0.1563 · x (R ² = 0.9701), and the determination coefficient (correlation coefficient) R ² is a high value. As a result of the linear regression of the measured values of the pressure gradient i and the flow velocity v in this way, the range of the pressure gradient i in which the coefficient of determination is sufficiently high and a significant linear approximation can be obtained is specified and obtained from the measured values in that range. The air permeability coefficient K of each specimen is determined by the regression coefficient in the linear regression equation (v = K · i) of the pressure gradient i and the flow velocity v. Table 6 shows the air permeability coefficient K of the specimen 1, the specimen 2, and the specimen 3 obtained as described above.

1: Permeability check test device,
10: outer frame, 11: support base, 12: air inflow pipe, 13: lid member,
20: flow sensor, 21: pressure sensor, 22: valve,
30: Air supply device,
M: Columnar specimen, G1, G2: Airtight resin (epoxy resin)

Claims (6)

A columnar specimen having a set height (L) and a constant cross-sectional area (A) in which an airtight resin is applied to the side surface is formed by the filling material to be tested,
The pressure (h) and the flow rate (Q) of the inflowed air are set for a set time (t) while air at a constant pressure is introduced from one of the open end faces of the columnar specimen and the other end face is opened to the atmosphere. ) Measuring and determining the air permeability coefficient K according to the following formula (1):
K = (L / h) × {Q / (A · t)} (1)
here,
L: Height of the columnar specimen A: Cross-sectional area of the columnar specimen h: Pressure of air flowing in Q: Flow rate of air flowing in t: Measurement time A columnar specimen having a set height (L) and a constant cross-sectional area (A) in which an airtight resin is applied to the side surface is formed by the filling material to be tested,
The pressure (h) and the flow rate (Q) of the inflowed air are set for a set time (t) while air at a constant pressure is introduced from one of the open end faces of the columnar specimen and the other end face is opened to the atmosphere. ) Measure and
With the flow rate (Q) measured for each of the different pressures (h), a linear regression through the origin is performed in the relationship between the pressure gradient i and the flow velocity v, and within a range of the pressure gradient in which a significant linear approximation is obtained. An air permeability confirmation test method for an air permeable filling material, wherein an air permeability coefficient K of a columnar specimen is determined by a regression coefficient in a linear regression equation of the pressure gradient and the flow velocity.
However,
L: Height of the columnar specimen A: Cross-sectional area of the columnar specimen h: Inflowing air pressure Q: Inflowing air flow t: Measurement time i: Pressure gradient v: Flow velocity Q / (A · t), i = h / L   3. The air permeability confirmation test method for an air permeable filling material according to claim 1, wherein the airtight resin is an epoxy resin having a high viscosity. An outer frame for supporting a columnar specimen having a set height and a constant cross-sectional area formed of a filling material to be tested and coated with an airtight resin on a side surface;
A support base for supporting the outer frame while supporting a discharge end of an air inflow pipe that allows air to flow into one of the open end faces of the columnar specimen, toward one of the end faces;
A flow rate sensor for measuring a flow rate of air flowing through the air inflow pipe;
A pressure sensor for measuring the pressure of air flowing into the air inlet pipe;
An air supply confirmation test device for air permeable filling material, comprising: an air supply device for introducing air into the air inflow pipe at a set constant pressure.   The air supply device according to claim 4, wherein the air supply device can variably adjust a set pressure.   The air permeability check test apparatus for air permeable filling materials according to claim 4 or 5, wherein the columnar specimen is supported by filling the outer frame with an airtight resin having a predetermined height.

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