JP2012117818A - Simplified computation method for permeability coefficient and simplified computation device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simplified computation method for a permeability coefficient and a simplified computation device therefor capable of easily and quickly obtaining the permeability coefficient of a specimen.SOLUTION: A method for computing a permeability coefficient of a columnar specimen where a nonpenetrating water filling hole is coaxially provided includes the following steps: a provisional permeability coefficient is obtained on the assumption that a flow in the specimen during a permeability test is a two-dimentional emission flow (step S1); on the other hand, a conversion factor a showing a nonpenetrating effect of the water filling hole is obtained (step S2); and the permeability coefficient k is computed by converting the provisional permeability coefficient with the conversion factor a (step S3).

Description

  The present invention relates to a simple calculation method and apparatus for hydraulic conductivity.

  2. Description of the Related Art Conventionally, a water permeability test method for evaluating the water permeability characteristics of rocks by laboratory tests is known (for example, see Non-Patent Document 1). In addition, for the purpose of investigating changes in permeability characteristics under the shear deformation of rocks, a shear fracture permeability test method is known in which a permeability test is performed in the middle of a triaxial compression test (for example, Patent Document 1 and Non-Patent Document). 2).

  5 and 6 show a specimen and a test apparatus used in the shear fracture permeability test of Non-Patent Document 2. As shown in FIG. 5, in the shear fracture permeability test of Non-Patent Document 2, a cylindrical specimen having a non-penetrated water injection hole provided coaxially is used. As shown in FIG. 6, the test apparatus uses a drainage plate with a groove between the lower end of the specimen and the pedestal, while a drainage material is wound around the side face of the specimen, and the outside is covered with a membrane.

  Then, when the specimen reaches a predetermined stress state or strain state during the triaxial compression test, a water permeability test is performed by a constant water level method while maintaining a constant axial displacement. In this water permeability test, when a shear fracture surface is formed on the specimen, a method using a radiant flow is adopted so that the influence can be taken into consideration.

  Specifically, as shown in FIG. 6, when a certain differential pressure is applied to the water injection hole and the side surface of the test piece, the water flowing into the test body from the water injection hole is transferred to the side surface of the test piece, the drainage material, and the groove of the drainage plate. It passes through and drains in order. The passing flow rate Q at this time is measured, and the hydraulic conductivity k is calculated based on the flow rate Q. Here, since the flow inside the specimen is not a perfect two-dimensional radiant flow, the following theoretical formula of the radiant flow shown in Non-Patent Document 1 is shown as a calculation formula for the permeability coefficient k [m / s] of the specimen. (1) cannot be applied as it is.

ここに、Ｑは計測された流量［ｍ^３／ｓ］、ｒ_１は注水孔の半径［ｍ］、ｒ_２は供試体の半径［ｍ］、Ｌ_２は供試体の高さ［ｍ］である。

Where Q is the measured flow rate [m ³ / s], r ₁ is the radius of the water injection hole [m], r ₂ is the radius of the specimen [m], and L ₂ is the height of the specimen [m]. is there.

  For this reason, conventionally, the hydraulic conductivity k has been calculated by repeatedly performing an axisymmetric FEM steady osmotic flow analysis by a computer as in Non-Patent Document 2. An example of this analysis model is shown in FIG.

As shown in FIG. 7, the boundary conditions of the analysis are as follows. In order to reproduce the state of the water permeability test, the upper and lower end surfaces of the specimen are made impermeable, the water head h ₁ [m] of the pore water pressure on the water injection hole side and the side surface of the specimen The water head difference Δh (= h ₁ −h ₂ ) [m] of the water head h ₂ [m] of the pore water pressure on the side is given so as to be the same as the water head converted value of the pressure difference of the pore water pressure during the water permeability test. Then, the flow rate q [m ³ / s] of water discharged from the side surface of the specimen is obtained by the above-described axially symmetric FEM steady osmotic flow analysis, and the flow rate Q [m ³ / s] measured during the permeability test is obtained. Until it agrees, the permeability coefficient k [m / s] of the specimen is determined by repeating the analysis while changing the permeability coefficient k [m / s] of the specimen. The calculation procedure of the hydraulic conductivity in this case is as shown in FIG.

JP 2000-9631 A

"Investigation and testing of rocks" (Chapter 48 Indoor Permeability Test), Geotechnical Society of Japan (currently Geotechnical Society of Japan), September 1989 “Proposal of permeability change model in soft rock excavation affected area”, Mitsuo Goya, Koji Kino, Tunnel Society Committee of Japan Society of Civil Engineers, Tunnel Engineering Papers Vol. 19, pp. 59-68, November 2009

  By the way, in order to obtain one water permeability coefficient, it is necessary to repeat the analysis by the above computer at least 4 to 5 times based on experience, and the water permeability coefficient cannot be obtained easily and quickly. Moreover, not everyone could easily check the calculation results. For this reason, development of the technique which can obtain | require the permeability coefficient of a test body simply and rapidly was calculated | required.

  This invention is made | formed in view of the above, Comprising: It aims at providing the simple calculation method and apparatus of a water permeability coefficient which can obtain | require the water permeability coefficient of a test body easily and rapidly.

  In order to solve the above-mentioned problems and achieve the object, the simple calculation method of the hydraulic conductivity according to claim 1 of the present invention is based on the hydraulic conductivity of a columnar specimen in which non-penetrating water injection holes are provided coaxially. By calculating the provisional permeability coefficient when assuming that the flow in the specimen during the permeability test is a two-dimensional radiant flow with a conversion coefficient that represents the non-penetration effect of the water injection hole. It is characterized by calculating the hydraulic conductivity.

ここに、Ｑは透水試験時に計測された流量［ｍ^３／ｓ］、πは円周率、Δｈは注水孔側の間隙水圧の水頭ｈ_１［ｍ］と供試体側面側の間隙水圧の水頭ｈ_２［ｍ］の水頭差（ｈ_１−ｈ_２）［ｍ］、ｒ_１は注水孔の半径［ｍ］、ｒ_２は供試体の半径［ｍ］、Ｌ_２は供試体の高さ［ｍ］である。また、ａはｒ_１／ｒ_２とＬ_１／Ｌ_２の関係に基づいて決定する換算係数であり、Ｌ_１は注水孔の深さ［ｍ］である。 In addition, a simple method for calculating a permeability coefficient according to claim 2 of the present invention is characterized in that, in claim 1 described above, the permeability coefficient k [m / s] of the specimen is calculated by the following equation.

Here, Q is the flow rate [m ³ / s] measured during the water permeability test, π is the circumference, Δh is the water head h ₁ [m] of the pore water pressure on the water injection hole side, and the water head of the pore water pressure on the side surface of the specimen. h ₂ water head difference _{[m] (h 1 -h 2} ) [m], r 1 is the radius [m] of water injection hole, _{r 2} is the radius of the specimen [m], _{L 2} is the specimen height [ m]. Moreover, a is a conversion factor determined based on the relationship between r ₁ / r ₂ and L ₁ / L ₂ , and L ₁ is the depth [m] of the water injection hole.

ただし、上記の式中のｂは、下記の式で与えられる。

ここに、Ｑは透水試験時に計測された流量［ｍ^３／ｓ］、πは円周率、Δｈは注水孔側の間隙水圧の水頭ｈ_１［ｍ］と供試体側面側の間隙水圧の水頭ｈ_２［ｍ］の水頭差（ｈ_１−ｈ_２）［ｍ］、ｒ_１は注水孔の半径［ｍ］、ｒ_２は供試体の半径［ｍ］、Ｌ_２は供試体の高さ［ｍ］である。また、ａはｒ_１／ｒ_２とＬ_１／Ｌ_２の関係に基づいて決定する換算係数であり、Ｌ_１は注水孔の深さ［ｍ］である。 In addition, a simple method for calculating a water permeability coefficient according to claim 3 of the present invention is characterized in that, in claim 1 described above, the water permeability coefficient k [m / s] of the specimen is calculated by the following equation.

However, b in the above formula is given by the following formula.

Here, Q is the flow rate [m ³ / s] measured during the water permeability test, π is the circumference, Δh is the water head h ₁ [m] of the pore water pressure on the water injection hole side, and the water head of the pore water pressure on the side surface of the specimen. h ₂ water head difference _{[m] (h 1 -h 2} ) [m], r 1 is the radius [m] of water injection hole, _{r 2} is the radius of the specimen [m], _{L 2} is the specimen height [ m]. Moreover, a is a conversion factor determined based on the relationship between r ₁ / r ₂ and L ₁ / L ₂ , and L ₁ is the depth [m] of the water injection hole.

Further, the simple method of calculating hydraulic conductivity according to claim 4 of the present invention, in any one of claims 1 to 3 described above, the conversion factor, the radius r ₁ of the previously obtained water injection hole by computer analysis It is determined based on the ratio of the radius r ₂ of the specimen (r ₁ / r ₂ ) and the ratio of the depth L ₁ of the water injection hole and the height L ₂ of the specimen (L ₁ / L ₂ ). Features.

  Moreover, the simple calculation apparatus of the hydraulic conductivity which concerns on Claim 5 of this invention is an apparatus which calculates the hydraulic conductivity of the column-shaped test body in which the non-penetrating water injection hole was provided coaxially, Comprising: Calculation unit that calculates the hydraulic conductivity by converting the temporary hydraulic conductivity when assuming that the flow in the specimen during the test is a two-dimensional radiant flow with a conversion coefficient that represents the non-penetration effect of the water injection hole. It is characterized by providing.

ここに、Ｑは透水試験時に計測された流量［ｍ^３／ｓ］、πは円周率、Δｈは注水孔側の間隙水圧の水頭ｈ_１［ｍ］と供試体側面側の間隙水圧の水頭ｈ_２［ｍ］の水頭差（ｈ_１−ｈ_２）［ｍ］、ｒ_１は注水孔の半径［ｍ］、ｒ_２は供試体の半径［ｍ］、Ｌ_２は供試体の高さ［ｍ］である。また、ａはｒ_１／ｒ_２とＬ_１／Ｌ_２の関係に基づいて決定する換算係数であり、Ｌ_１は注水孔の深さ［ｍ］である。 Moreover, the simple calculation device of the water permeability coefficient according to claim 6 of the present invention is characterized in that, in claim 5 described above, the calculation unit calculates the water permeability coefficient k [m / s] of the specimen by the following equation. And

Here, Q is the flow rate [m ³ / s] measured during the water permeability test, π is the circumference, Δh is the water head h ₁ [m] of the pore water pressure on the water injection hole side, and the water head of the pore water pressure on the side surface of the specimen. h ₂ water head difference _{[m] (h 1 -h 2} ) [m], r 1 is the radius [m] of water injection hole, _{r 2} is the radius of the specimen [m], _{L 2} is the specimen height [ m]. Moreover, a is a conversion factor determined based on the relationship between r ₁ / r ₂ and L ₁ / L ₂ , and L ₁ is the depth [m] of the water injection hole.

ただし、上記の式中のｂは、下記の式で与えられる。

ここに、Ｑは透水試験時に計測された流量［ｍ^３／ｓ］、πは円周率、Δｈは注水孔側の間隙水圧の水頭ｈ_１［ｍ］と供試体側面側の間隙水圧の水頭ｈ_２［ｍ］の水頭差（ｈ_１−ｈ_２）［ｍ］、ｒ_１は注水孔の半径［ｍ］、ｒ_２は供試体の半径［ｍ］、Ｌ_２は供試体の高さ［ｍ］である。また、ａはｒ_１／ｒ_２とＬ_１／Ｌ_２の関係に基づいて決定する換算係数であり、Ｌ_１は注水孔の深さ［ｍ］である。 Moreover, the simple calculation apparatus of the hydraulic conductivity which concerns on Claim 7 of this invention is characterized by the calculation part calculating the hydraulic conductivity k [m / s] of a test piece by the following formula in Claim 5 mentioned above. And

However, b in the above formula is given by the following formula.

Here, Q is the flow rate [m ³ / s] measured during the water permeability test, π is the circumference, Δh is the water head h ₁ [m] of the pore water pressure on the water injection hole side, and the water head of the pore water pressure on the side surface of the specimen. h ₂ water head difference _{[m] (h 1 -h 2} ) [m], r 1 is the radius [m] of water injection hole, _{r 2} is the radius of the specimen [m], _{L 2} is the specimen height [ m]. Moreover, a is a conversion factor determined based on the relationship between r ₁ / r ₂ and L ₁ / L ₂ , and L ₁ is the depth [m] of the water injection hole.

Also, a simple calculating device of permeability according to Claim 8 of the present invention, in any one of claims 5-7 as described above, the specimen and the radius r ₁ of the previously obtained water injection hole by computer analysis radius Data representing the relationship between the ratio of r ₂ (r ₁ / r ₂ ), the ratio of the depth L ₁ of the water injection hole to the height L ₂ of the specimen (L ₁ / L ₂ ), and the conversion coefficient was stored. A data storage unit is further provided, and the calculation unit calculates the hydraulic conductivity by referring to the data from the data storage unit.

  According to the simple calculation method of the hydraulic conductivity according to the present invention, the method of calculating the hydraulic conductivity of a cylindrical specimen provided with a non-penetrating water injection hole coaxially, the flow in the specimen during the permeability test Since the permeability coefficient is calculated by converting the temporary permeability coefficient when assuming that is a two-dimensional radiant flow with a conversion coefficient representing the non-penetration effect of the water injection hole, the permeability coefficient of the specimen is simplified and There is an effect that it can be quickly obtained.

  Further, according to the simple calculation device for the hydraulic conductivity according to the present invention, it is a device for calculating the hydraulic conductivity of a cylindrical specimen having a non-penetrating water injection hole coaxially using a computer, and at the time of the hydraulic test It is equipped with a calculation unit that calculates the hydraulic conductivity by converting the temporary hydraulic conductivity when assuming that the flow in the specimen is a two-dimensional radiant flow with a conversion coefficient that represents the non-penetration effect of the water injection hole. Therefore, there is an effect that the permeability coefficient of the specimen can be obtained easily and quickly.

FIG. 1 is a schematic flowchart showing an embodiment of a simple method for calculating a hydraulic conductivity according to the present invention. FIG. 2 is a diagram illustrating an example of the relationship between the conversion coefficient a and L ₁ / L ₂ . FIG. 3 is a diagram illustrating an example of the relationship between the coefficient b and L ₁ / L ₂ . FIG. 4 is a schematic configuration diagram showing an embodiment of a simple permeability calculating device according to the present invention. FIG. 5 is a perspective view showing an appearance of a specimen used for the water permeability test. FIG. 6 is a cross-sectional view showing a test apparatus for a water permeability test. FIG. 7 is a diagram illustrating an example of an axially symmetric FEM steady osmotic flow analysis model. FIG. 8 is a flowchart showing a procedure for calculating the hydraulic conductivity of a conventional specimen.

  As described above, conventionally, the hydraulic conductivity could not be determined easily and easily, and the result check was not easy. For this reason, the present inventor, as a method that can be easily calculated as long as there is a calculator, combines a conventional equation for calculating the hydraulic conductivity by a two-dimensional radial flow and a conversion factor that represents the effect of non-penetration, and thereby provides incomplete radiation. We devised a method that can calculate hydraulic conductivity even in the flow.

  Hereinafter, embodiments of a simple calculation method and apparatus for a hydraulic conductivity according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

[Simple calculation method of hydraulic conductivity]
First, the Example of the simple calculation method of the hydraulic conductivity based on this invention is described.
As shown in FIG. 1, the simple calculation method for the hydraulic conductivity according to the present invention is a method for calculating the hydraulic conductivity of a cylindrical specimen provided with non-penetrating water injection holes coaxially. While obtaining a temporary water permeability coefficient when it is assumed that the flow in the specimen is a two-dimensional radiation flow (step S1), a conversion coefficient a representing the non-penetration effect of the water injection hole is obtained (step S2). And it is based on the procedure of calculating the hydraulic conductivity k by converting a temporary hydraulic conductivity with this conversion coefficient a (step S3).

  In step S1, the provisional hydraulic conductivity is calculated by the theoretical formula (1) of the radiant flow from the flow rate Q and the like measured in the hydraulic test.

  In step S2, the conversion coefficient a representing the non-penetrating effect of the water injection hole is obtained in advance using the above-described FEM steady osmotic flow analysis by the computer. More specifically, the hydraulic conductivity and hydraulic head difference are given to the analysis model (specimen), the flow rate coming out from the side of the analysis model is obtained, and the hydraulic conductivity is calculated from the flow rate using the theoretical formula (1) of the radiant flow. Finally, the conversion coefficient a corresponding to the shape of the analysis model can be obtained by dividing the permeability coefficient given to the analysis model by the permeability coefficient obtained from the theoretical formula (1).

Here, the conversion factor a is a parameter study on the radius r ₁ and the depth L ₁ of the water injection hole for each ratio (r ₂ : L ₂ ) between the radius r ₂ and the height L ₂ of the specimen. Thus, it is obtained in advance in association with various specimens and dimensions of the water injection hole.

FIG. 2 shows an example of the relationship between the conversion factor a and L ₁ / L ₂ obtained in advance, and is a relationship diagram when the ratio of the size of the specimen is r ₂ : L ₂ = 1: 4. is there. With reference to the relational diagram as shown in FIG. 2, the conversion coefficient a corresponding to the ratio of the dimensions of the specimen and the water injection hole (L ₁ / L ₂ , r ₁ / r ₂ ) during the water permeability test can be obtained.

ここに、Ｑは透水試験時に計測された流量［ｍ^３／ｓ］、πは円周率、Δｈは注水孔側の間隙水圧の水頭ｈ_１［ｍ］と供試体側面側の間隙水圧の水頭ｈ_２［ｍ］の水頭差（ｈ_１−ｈ_２）［ｍ］、ｒ_１は注水孔の半径［ｍ］、ｒ_２は供試体の半径［ｍ］、Ｌ_２は供試体の高さ［ｍ］である。また、ａはｒ_１／ｒ_２とＬ_１／Ｌ_２の関係に基づいて決定する換算係数であり、Ｌ_１は注水孔の深さ［ｍ］である。 A simple calculation formula for the hydraulic conductivity k [m / s] in Step S3 is shown in Formula (2).

Here, Q is the flow rate [m ³ / s] measured during the water permeability test, π is the circumference, Δh is the water head h ₁ [m] of the pore water pressure on the water injection hole side, and the water head of the pore water pressure on the side surface of the specimen. h ₂ water head difference _{[m] (h 1 -h 2} ) [m], r 1 is the radius [m] of water injection hole, _{r 2} is the radius of the specimen [m], _{L 2} is the specimen height [ m]. Moreover, a is a conversion factor determined based on the relationship between r ₁ / r ₂ and L ₁ / L ₂ , and L ₁ is the depth [m] of the water injection hole.

As described above, the conversion coefficient a in the above equation (2) can be obtained from the dimensions of the specimen and the water injection hole and FIG. For example, when the radius r ₂ = 25 mm of the specimen, the height L ₂ = 100 mm, the radius r ₁ = 3 mm of the water injection hole, and the depth L ₁ = 80 mm, r ₁ / r ₂ = 0.12 and L ₁ / L ₂ = 0.8, and a = 1.16 is obtained from FIG.

とおけば、さらに簡略化した形となる。この場合、透水係数ｋ［ｍ／ｓ］は、以下の式（３）のようになる。 Moreover, about said Formula (2),

Then, it becomes a simplified form. In this case, the water permeability coefficient k [m / s] is expressed by the following equation (3).

上記の式（３）中の係数ｂは、供試体と注水孔の寸法と図３より求めることができる。例えば、供試体の半径ｒ_２＝２５ｍｍ、高さＬ_２＝１００ｍｍ、注水孔の半径ｒ_１＝３ｍｍ、深さＬ_１＝８０ｍｍの場合、ｒ_１／ｒ_２＝０．１２、Ｌ_１／Ｌ_２＝０．８となって、図３からｂ＝０．３９１と求められる。ただし、図３も、供試体の大きさの比がｒ_２：Ｌ_２＝１：４の場合の関係図である。

The coefficient b in the above equation (3) can be obtained from the dimensions of the specimen and the water injection hole and FIG. For example, when the radius r ₂ = 25 mm of the specimen, the height L ₂ = 100 mm, the radius r ₁ = 3 mm of the water injection hole, and the depth L ₁ = 80 mm, r ₁ / r ₂ = 0.12 and L ₁ / L ₂ = 0.8, and b = 0.391 is obtained from FIG. However, FIG. 3 is also a relationship diagram in the case where the ratio of the size of the specimens is r ₂ : L ₂ = 1: 4.

  From the above formula (2) or formula (3), the water permeability coefficient of the specimen can be obtained easily and quickly. In particular, since it can be calculated once with a calculator or the like, the efficiency of obtaining the hydraulic conductivity becomes very good. Also, anyone with a calculator can make calculations, so anyone can easily check the results. According to the verification by the present inventor, the difference between the hydraulic conductivity calculated according to the present invention and the hydraulic conductivity obtained by the conventional axisymmetric FEM steady osmotic flow analysis was about several percent. Is considered to be sufficiently accurate.

[Simple calculation device for hydraulic conductivity]
Next, the Example of the simple calculation apparatus of the hydraulic conductivity which concerns on this invention is described.
As shown in FIG. 4, the simple calculation device 10 of the hydraulic conductivity according to the present invention is a device that calculates the hydraulic conductivity of a cylindrical specimen having a non-penetrating water injection hole coaxially using a computer. , An input unit 12, an output unit 14, a calculation unit 16, a data storage unit 18 and a control unit 20 for controlling them.

  The calculation unit 16 converts the temporary permeability coefficient when assuming that the flow in the test body at the time of the permeability test is a two-dimensional radiant flow by the conversion coefficient a representing the non-penetration effect of the water injection hole, The hydraulic conductivity k is calculated. For this, the above formula (2) or formula (3) is used.

Data storage unit 18, a radius _{r 1} and a ratio of the specimen of radius _{r 2} of the water injection hole and _(r 1 / _{r 2),} the ratio of the height _{L 2} of the depth _{L 1} and specimen water injection holes _{(L 1} / L ₂ ) and the conversion coefficient a or the coefficient b (see FIG. 2 or FIG. 3) are stored as data.

In the above configuration, when the user inputs the specimen and the size of the water injection hole, the measured flow rate, and the like at the time of the permeability test from the input unit 12 such as a keyboard, the control unit 20 refers to the data in the data storage unit 18 and The conversion factor a or the factor b corresponding to the ratio of the test specimen and the water injection hole size (L ₁ / L ₂ , r ₁ / r ₂ ) at the time of the test is acquired and transmitted to the calculation unit 16. The computing unit 16 calculates the water permeability coefficient k by substituting the conversion coefficient a or coefficient b and the input value from the input unit 12 into the above formula (2) or formula (3). The calculation result is displayed on the output unit 14 such as a monitor. Thus, according to the simple calculation device 10 of the present invention, the permeability coefficient of the specimen can be obtained simply and quickly simply by inputting the dimensions of the specimen and the water injection hole, the measured flow rate, etc. during the permeability test. .

  In addition, the simple calculation method and apparatus of the hydraulic conductivity based on this invention are suitable for the hydraulic permeability test performed in the middle of the triaxial compression test for the purpose of investigating the change of the hydraulic permeability characteristic under the shear deformation of a rock. However, if the specimen is in the form as shown in FIG. 5 and the test mode is as shown in FIG. 6, it can be applied to a water permeability test without a triaxial compression test.

  As described above, according to the simple method for calculating the hydraulic conductivity according to the present invention, the method of calculating the hydraulic conductivity of a cylindrical specimen provided with a non-penetrating water injection hole coaxially, and at the time of the hydraulic test Since the permeability coefficient is calculated by converting the temporary permeability coefficient when assuming that the flow in the specimen is a two-dimensional radiant flow with the conversion coefficient that represents the non-penetration effect of the water injection hole, The permeability coefficient can be determined easily and quickly.

  Further, according to the simple calculation device for the hydraulic conductivity according to the present invention, it is a device for calculating the hydraulic conductivity of a cylindrical specimen having a non-penetrating water injection hole coaxially using a computer, and at the time of the hydraulic test It is equipped with a calculation unit that calculates the hydraulic conductivity by converting the temporary hydraulic conductivity when assuming that the flow in the specimen is a two-dimensional radiant flow with a conversion coefficient that represents the non-penetration effect of the water injection hole. Therefore, the permeability coefficient of the specimen can be obtained easily and quickly.

  As described above, the simple calculation method and apparatus for hydraulic conductivity according to the present invention are performed using a cylindrical specimen having a non-penetrated water injection hole coaxially for evaluating the hydraulic characteristics of rock. It is useful for indoor permeability tests, and is particularly suitable for obtaining the permeability coefficient of a specimen easily and quickly.

DESCRIPTION OF SYMBOLS 10 Simple permeability calculation apparatus 12 Input part 14 Output part 16 Calculation part 18 Data storage part 20 Control part

Claims (8)

A method for calculating the hydraulic conductivity of a cylindrical specimen provided with non-penetrating water injection holes coaxially,
Calculate the permeability coefficient by converting the temporary permeability coefficient assuming that the flow in the specimen during the permeability test is a two-dimensional radiant flow with a conversion coefficient that represents the non-penetration effect of the water injection hole. Simple calculation method of hydraulic conductivity characterized by The simple permeability calculation method of the permeability coefficient according to claim 1, wherein the permeability coefficient k [m / s] of the specimen is calculated by the following formula.

Here, Q is the flow rate [m ³ / s] measured during the water permeability test, π is the circumference, Δh is the water head h ₁ [m] of the pore water pressure on the water injection hole side, and the water head of the pore water pressure on the side surface of the specimen. h ₂ water head difference _{[m] (h 1 -h 2} ) [m], r 1 is the radius [m] of water injection hole, _{r 2} is the radius of the specimen [m], _{L 2} is the specimen height [ m]. Moreover, a is a conversion factor determined based on the relationship between r ₁ / r ₂ and L ₁ / L ₂ , and L ₁ is the depth [m] of the water injection hole. The simple permeability calculation method of the permeability coefficient according to claim 1, wherein the permeability coefficient k [m / s] of the specimen is calculated by the following formula.

However, b in the above formula is given by the following formula.

Here, Q is the flow rate [m ³ / s] measured during the water permeability test, π is the circumference, Δh is the water head h ₁ [m] of the pore water pressure on the water injection hole side, and the water head of the pore water pressure on the side surface of the specimen. h ₂ water head difference _{[m] (h 1 -h 2} ) [m], r 1 is the radius [m] of water injection hole, _{r 2} is the radius of the specimen [m], _{L 2} is the specimen height [ m]. Moreover, a is a conversion factor determined based on the relationship between r ₁ / r ₂ and L ₁ / L ₂ , and L ₁ is the depth [m] of the water injection hole. The ratio (r ₁ / r ₂ ) between the radius r _{1 of the} water injection hole and the radius r ₂ of the specimen, which was previously determined by computer analysis, the depth L ₁ of the water injection hole and the height L _{2 of the} specimen. the ratio _(L 1 _/ L ₂₎ simple calculation method for permeability according to any one of claims 1 to 3, characterized in that determining on the basis of the relation. An apparatus for calculating the permeability coefficient of a cylindrical specimen having a non-penetrated water injection hole coaxially using a computer,
Calculation to calculate the permeability coefficient by converting the temporary permeability coefficient when assuming that the flow in the specimen during the permeability test is a two-dimensional radiant flow with a conversion coefficient that represents the non-penetration effect of the injection hole. A simple calculation device for hydraulic conductivity, comprising a section. 6. The simple calculation device for hydraulic conductivity according to claim 5, wherein the calculation unit calculates the hydraulic conductivity k [m / s] of the specimen by the following formula.

Here, Q is the flow rate [m ³ / s] measured during the water permeability test, π is the circumference, Δh is the water head h ₁ [m] of the pore water pressure on the water injection hole side, and the water head of the pore water pressure on the side surface of the specimen. h ₂ water head difference _{[m] (h 1 -h 2} ) [m], r 1 is the radius [m] of water injection hole, _{r 2} is the radius of the specimen [m], _{L 2} is the specimen height [ m]. Moreover, a is a conversion factor determined based on the relationship between r ₁ / r ₂ and L ₁ / L ₂ , and L ₁ is the depth [m] of the water injection hole. 6. The simple calculation device for hydraulic conductivity according to claim 5, wherein the calculation unit calculates the hydraulic conductivity k [m / s] of the specimen by the following formula.

However, b in the above formula is given by the following formula.

Here, Q is the flow rate [m ³ / s] measured during the water permeability test, π is the circumference, Δh is the water head h ₁ [m] of the pore water pressure on the water injection hole side, and the water head of the pore water pressure on the side surface of the specimen. h ₂ water head difference _{[m] (h 1 -h 2} ) [m], r 1 is the radius [m] of water injection hole, _{r 2} is the radius of the specimen [m], _{L 2} is the specimen height [ m]. Moreover, a is a conversion factor determined based on the relationship between r ₁ / r ₂ and L ₁ / L ₂ , and L ₁ is the depth [m] of the water injection hole. The ratio (r ₁ / r ₂ ) of the radius r _{1 of the} water injection hole and the radius r ₂ of the specimen obtained in advance by analysis by a computer, and the ratio of the depth L ₁ of the water injection hole and the height L ₂ of the specimen (L ₁ / L ₂ ) and a data storage unit storing data representing the conversion coefficient,
The simple calculation device for the hydraulic conductivity according to any one of claims 5 to 7, wherein the calculation unit calculates the hydraulic conductivity by referring to the data from the data storage unit.

Images