JP6963917B2 - Permeability evaluation test method and equipment - Google Patents

Description

The present invention relates to a test method and an apparatus for evaluating the permeability of an injection material into a ground, and in particular, a test suitable for examining an evaluation item related to the penetration rate, penetration time, penetration distance and other permeability of the injection material. Regarding methods and devices.

For example, when constructing a structure such as a tunnel or a building, it is known to improve the ground by injecting an injection material into a fragile ground or a loose ground.
Since the properties of the ground differ from construction site to construction site, it is necessary to select an injection material that matches the ground at the site. Therefore, the following evaluation tests are conducted.

First, prepare a test container such as a drum. Place the injection tube along the axis of the test vessel. The upper end of the injection tube should protrude above the test vessel.
Next, the inside of the test container is filled with a simulated ground that looks like a ground, and the injection pipe is buried in the simulated ground. As the simulated ground, for example, permeable silica sand equivalent to the ground at the application site is used.
Then, the injection material is supplied to the injection tube. As the injection material, for example, a urethane-based injection material, a cement-based injection material, or the like is used. The injection material is discharged from the injection hole of the injection pipe and penetrates into the simulated ground.
After curing until the injection material hardens, break the test container and take out the simulated ground. Then, it is evaluated whether or not the desired improvement effect can be obtained from the size, shape, hardness, and other physical characteristics of the portion improved by the injection material.

Japanese Unexamined Patent Publication No. 06-287557

In the conventional test, the permeation distance and permeation range of the injection material into the simulated ground cannot be known unless the test container is disassembled. Moreover, the permeation rate and permeation time cannot be known at all.
In view of such circumstances, the present invention can measure the permeation rate, permeation time, permeation distance, permeation range and other permeation evaluation items of the injection material into the ground without disassembling the test container, and the penetration of the injection material. It is an object of the present invention to provide a test method and a test apparatus capable of accurately evaluating the properties.

In order to solve the above problems, the method of the present invention is a test method for evaluating the permeability of an injection material into a ground.
The simulated ground is housed in an elongated tubular test container that allows the inside to be seen through.
The injection material is injected into the simulated ground from an injection pipe inserted and arranged in the test container.
The apparatus of the present invention is a test apparatus for evaluating the permeability of an injection material into a ground.
A test container that is formed in an elongated tubular shape that allows the inside to be seen through and contains a simulated ground,
It is characterized by being provided with an injection tube which is inserted and arranged in the test container and injects the injection material into the simulated ground.

Since the inside of the test container can be seen through, the outer peripheral portion of the simulated ground inside the test container can be visually recognized from the outside of the test container.
Further, by making the test container elongated, the injection material reaches the outer peripheral portion of the simulated ground in a short time after the start of the injection process, and the penetration state of the injection material can be visually recognized through the transparent test container.
Since the test container is thin and transparent, the overall permeation status of the injection material can be grasped from the outside of the test container. That is, there is not much difference in the degree of penetration of the injection material between the central portion and the outer peripheral portion of the simulated ground, and it is sufficient if the permeation state at the outer peripheral portion can be observed.
Further, by increasing the axial length of the test container, the injection material can be diffused to the limit position where it can be diffused. That is, it is possible to prevent the injection material from reaching the end of the test container with diffusion energy remaining and being prevented from diffusing.
As a result, the permeation rate, permeation time, permeation distance, permeation range and other permeation evaluation items of the injection material can be measured without disassembling the test container, and the permeation of the injection material can be accurately evaluated. ..

It is preferable that the injection material is colored. As a result, the injection material and the simulated ground can be easily distinguished, and the permeability evaluation can be performed more accurately.

The inner diameter of the test container is preferably about 50 mm to 300 mm. As a result, the degree of penetration of the injection material in the central part of the simulated ground in the test container and the degree of penetration of the injection material in the outer peripheral part can be surely made almost the same, and the penetration state in the outer peripheral part can be tested for transparency. By visually observing through the container, the overall permeation status of the injection material can be grasped.
The height of the test container is preferably larger than the inner diameter and is preferably 300 mm to 2000 mm. This ensures that the injection material can diffuse to the limit position where it can diffuse along the axis of the test vessel and thus the simulated ground.

It is preferable that the test container has an elongated tubular body portion made of a translucent material and a lid portion that closes an end portion of the body portion.
Since at least the inside of the body can be seen through, the permeation state of the injection material can be observed from the outside of the test container through the body.
The axis of the body is preferably oriented vertically or vertically.
The lid does not necessarily have to be transparent to the inside, and may be made of a non-transmissive material.
The lid may be provided at at least one end (for example, the lower end) of the body. Preferably, both ends of the body are closed with lids.

It is preferable that the lid portion is formed with a ventilation hole, and the ventilation hole is provided with a filter that allows the permeation of gas and liquid and prevents the permeation of solids.
As a result, the air in the test container can be discharged from the ventilation hole as the injection material is injected. In addition, excess water can be pushed out from the ventilation holes. As a result, the injection material can be smoothly injected. On the other hand, by providing a filter in the ventilation hole, it is possible to prevent the simulated ground from leaking from the ventilation hole.

According to the present invention, the permeability of the injection material into the ground can be accurately evaluated.

FIG. 1 is a front sectional view of a permeability evaluation test apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the test container of the permeability evaluation test apparatus along the line II-II of FIG. FIG. 3A is a plan view of the test container along the line IIIa-IIIa of FIG. FIG. 3B is a bottom view of the test container along the line IIIb-IIIb of FIG. FIG. 4A is an enlarged cross-sectional view of the circular portion IVa of FIG. FIG. 4B is an enlarged cross-sectional view of the circular portion IVb of FIG. FIG. 5 shows the permeation state of the injection material by the permeability evaluation test device over time, and FIG. 5A is a front sectional view showing the start of injection of the injection material. FIG. 5B is a front sectional view of the stage where the injection material is diffused to the inner peripheral surface of the test device. FIG. 5C is a front sectional view of a stage in which the injection material diffuses and permeates while foaming. FIG. 5D is a front sectional view at the stage where the diffusion of the injection material has converged. FIG. 6 is a photograph of the permeation state of the injection material by the permeability evaluation test apparatus in Example 1 taken over time.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The embodiment of the present invention is applied to, for example, evaluation of an injection material for a pre-received work such as long steel pipe fore-piling or fore-polling in tunnel construction. In the pre-received work, a pre-received steel pipe such as a hollow bolt is driven into the ground in front of the tunnel, and the injection material is injected into the ground through the injection hole of the pre-received steel pipe to stabilize the ground. A permeability evaluation test is conducted in advance to select an injection material suitable for the ground.

FIG. 1 shows the permeability evaluation test device 1 of the present embodiment. The permeability evaluation test apparatus 1 includes a test container 10, an injection pipe 20, and a simulated ground 30. The test container 10 has a body portion 11 and lid portions 13 and 12.
As shown in FIGS. 1 and 2, the body portion 11 is formed in an elongated cylindrical shape. As a result, the test container 10 has an elongated cylindrical shape. The lower end of the body 11 is closed by the lid 13, and the upper end is closed by the lid 12.

The body portion 11 is made of a translucent material. As a result, the inside of the test container 10 can be seen through the body portion 11. Examples of the translucent material include transparent resin and glass.

As shown in FIG. 1, the internal space of the body portion 11 is a columnar test chamber 10a. _{The inner diameter φ 1} of the body portion 11 and thus the test chamber 10a is smaller than the height H _{1 (φ 1} <H ₁ ). Preferably, the inner diameter φ ₁ is less than half of the height H _{1 (φ 1} ≤ H ₁₃ ), more preferably less than one-third of the _{height H 1 (φ 1} ≤ H ₁₂ ), and more preferably. is about one or less 6 of the height _{H 1 (φ 1 ≒ H 1} /6, φ 1 ≦ H 1/6).
Specifically, the inner diameter φ ₁ of the test chamber 10a is preferably _{about φ 1} = 50 mm to 300 mm. _{The height H 1} of the test chamber 10a is preferably _{about H 1} = 300 mm to 2000 mm.

Of the test container 10, at least the body portion 11 may be transparent or translucent, and the lid portions 13 and 12 need not be transparent or translucent.
As shown in FIG. 3A, the upper lid portion 12 is made of a non-transmissive resin and is formed in a circular shape. A plurality of (four in the figure) ventilation holes 12d are formed in the lid portion 12. These ventilation holes 12d are arranged so as to be dispersed with each other in the circumferential direction of the lid portion 12. The number and arrangement of the ventilation holes 12d can be set as appropriate.

As shown in FIG. 4A, a filter 14 is provided on the surface (lower surface) of the lid portion 12 on the test chamber 10a side. The vent hole 12d is covered by the filter 14. The filter 14 allows the permeation of gases and liquids and blocks the permeation of solids. As the material of the filter 14, for example, a non-woven fabric is used.

As shown in FIG. 3B, the lower lid portion 13 (bottom plate) is made of a non-transmissive resin and is formed in a circular shape.
A plurality of (four in the figure) ventilation holes 13d are formed in the lid portion 13. These ventilation holes 13d are arranged so as to be dispersed with each other in the circumferential direction of the lid portion 13. The number and arrangement of the ventilation holes 13d can be set as appropriate.

As shown in FIG. 4B, a filter 15 is provided on the surface (upper surface) of the lid portion 13 on the test chamber 10a side. The vent hole 13d is covered by the filter 15. The filter 15 allows the permeation of gases and liquids and blocks the permeation of solids. As the material of the filter 15, for example, a non-woven fabric is used.

As shown in FIG. 1, the injection tube 20 is inserted and arranged inside the test container 10. The injection pipe 20 is made of a steel pipe and extends up and down along the axis of the test container 10. The upper end portion of the injection tube 20 penetrates the lid portion 12 and extends upward of the test container 10. The opening 20e at the lower end of the injection pipe 20 is arranged in the middle portion in the height direction of the test container 10. Preferably, the opening 20e is located at or slightly below the mid-height of the test vessel 10.

A simulated ground 30 is housed inside the test container 10. The injection pipe 20 is buried in the simulated ground 30.
As the simulated ground 30, earth and sand having similar physical properties and properties to the ground at the construction site are used. Preferably, as the simulated ground 30, silica sand having water permeability equivalent to that of the ground at the construction site is used.

As shown in FIG. 1, supply pipes 21A and 21B of the injection material 3 are connected to the upper end of the injection pipe 20. Here, a urethane-based injection material is used as the injection material 3. The raw material of the urethane-based injection material includes liquid A such as polyol and liquid B such as polyisocyanate. The supply source 3A of the liquid A is connected to the supply pipe 21A, and the supply source 3B of the liquid B is connected to the supply pipe 21B.

The coloring material 4 is added to either the liquid A or the liquid B. As a result, the injection material 3 is colored in the color of the coloring material 4. A dye is used as the coloring material 4. The coloring material 4 is not limited to dyes, and pigments may be used. In FIG. 1, although the coloring material 4 is added to the liquid A, it may be added to the liquid B or may be added to both the liquid A and the liquid B.
The color of the coloring material 4 is preferably a color that is complementary to the color of the simulated ground 30.
When a plurality of test containers 10 are prepared and a permeation test is performed on each of the plurality of types of injection materials 3, different colors may be applied to each of the injection materials 3.

The permeability evaluation test is performed as follows.
As shown in FIG. 1, the test container 10 is filled with the simulated ground 30.
Since the actual ground usually contains water, it is preferable to infiltrate the simulated ground 30 with water to bring it closer to the state of the actual ground. In addition, in order to obtain reference data and the like, it may not contain water.

As shown in FIG. 1, the urethane raw materials A and B are supplied from the supply pipes 21A and 21B to the injection pipe 20, respectively. The coloring material 4 is added to the liquid A or the liquid B. The liquids A and B are mixed to form a urethane-based injection material 3, which is discharged from the lower end opening 20e of the injection pipe 20 into the simulated ground 30.
Further, the injection material 3 diffuses and permeates up and down in the simulated ground 30. Specifically, as shown in FIGS. 5 (a) to 5 (b), the injection material 3 diffuses mainly downward in the liquid state before foaming, and foams as shown in FIGS. 5 (c) to 5 (d). Then, it mainly spreads upward.

Since the body 11 of the test container 10 is transparent and the inside can be seen through, the outer peripheral portion of the simulated ground 30 in the test container 10 can be visually recognized from the outside of the test container 10.
Moreover, since the test container 10 has an elongated tubular shape, as shown in FIG. 5B, the outermost portion 3e of the injection material 3 in the simulated ground 30 is simulated in a short time after the start of the injection step. It reaches the outer peripheral portion of the ground 30, and the outermost portion 3e can be visually recognized through the transparent body portion 11. By observing the permeation state of the outermost portion 3e, it is possible to grasp the permeation state of almost the entire injection material 3. That is, since the test container 10 is thin, there is not much difference in the degree of penetration of the injection material 3 between the central portion and the outer peripheral portion of the simulated ground 30, and it is sufficient if the permeation state at the outer peripheral portion can be observed.
Moreover, since the injection material 3 is colored, the injection material 3 and the simulated ground 30 can be easily distinguished, and the permeation state can be easily observed.
Further, by lengthening the shaft length of the test container 10 vertically, the injection material 3 can be diffused and permeated to a limit position where it can be diffused vertically, as shown in FIG. 5D. That is, it is possible to prevent the injection material 3 from reaching the upper end portion or the lower end portion of the test container 10 and being prevented from diffusing even though the diffusion energy still remains.
As a result, the permeation rate, permeation time, permeation range, permeation distance, etc. can be measured from the outside of the test container 10 without disassembling the test container 10, and the permeability of the injection material 3 can be accurately evaluated. ..
As shown in FIG. 5D, the permeation distance L is measured after the permeation is sufficiently settled. Preferably, the maximum value and the minimum value of the distance from the upper end portion to the lower end portion of the outermost portion 3e of the injection material 3 are measured, and the average value thereof is defined as the permeation distance L.

With the injection of the injection material 3, the air in the test container 10 passes through the filters 14 and 15 and is discharged from the ventilation holes 13d and 12d. Further, the excess water in the simulated ground 30 can also be passed through the filters 14 and 15 and pushed out from the ventilation holes 13d and 12d. As a result, the injection material 3 can be smoothly injected.
On the other hand, the silica sand of the simulated ground 30 is blocked by the filters 14 and 15 and can be prevented from leaking from the ventilation holes 13d and 12d.

By preparing a plurality of permeability evaluation test devices 1 and injecting injection materials 3 having different compositions from each other and performing permeability evaluation for each, it is possible to select the injection material 3 suitable for the ground to be applied. In this case, as described above, it is preferable to color each injection material 3 in a different color. Thereby, the type of the injection material 3 can be easily identified by the color.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the injection material is not limited to the urethane-based injection material, and a silica resin-based injection material, a cement-based injection material, or the like may be used. The silica resin-based injection material is a modified polyurethane using special sodium silicate (liquid A) and modified polyisocyanate (liquid B) as raw materials.
Since the cement-based injection material is mainly diffused downward in the simulated ground 30, the opening 20e of the injection pipe 20 may be arranged at a height near the upper end in the test chamber 10a.
The test container 10 may have an elongated cylindrical shape, and is not limited to a cylindrical shape, and may have a square cylinder or other polygonal cylinder shape.
The direction of the 10-axis line of the test container is not limited to vertical (vertical), and may be horizontal, or may be inclined with respect to vertical or horizontal.
Not only the body portion 11 but also the lid portions 12 and 13 may have translucency.
Of the lid portions 12 and 13 at both ends, one (for example, the lid portion 12) may be omitted.
In the present invention, in addition to the selection of the injection material of the long tip receiving method in which the long tip receiving steel pipe is driven forward from the outer circumference of the upper half arch of the face, the injection material of the mirror bolt method in which the mirror bolt is placed in the face mirror portion. It can also be applied to selection.
The present invention is not limited to the selection of an injection material into the ground when constructing a tunnel, but also the selection of an injection material as a ground improvement material when constructing other underground structures or building structures such as buildings. Applicable.

An embodiment will be described. However, the present invention is not limited to the following examples.
A permeability evaluation test device 1 substantially equivalent to that in FIG. 1 was produced.
A transparent polyvinyl chloride pipe was used as the body 11 of the test container 10.
The height H1 of the test chamber 10a _is H 1 = 1000 mm, an inner diameter phi ₁ was phi ₁ = 155mm.
The lower end opening 20e of the injection tube 20 was positioned at a height of 600 mm below the upper end of the test container 10.
As simulated natural ground 30, for example, No. 2 Silica sand (particle size 2-4 mm, about 35% porosity, permeability coefficient ¹⁰ 0 ^~10 1 cm / s) was used.
The simulated ground 30 was divided into 5 times and put into the test container 10 by free fall. It was compacted every time it was thrown in. Further, the simulated ground 30 was impregnated with water so that the water content was about 20 w%.
As the injection material 3, for example, a urethane-based injection material manufactured by Asahi Organic Materials Co., Ltd. was used. The injection amount of the injection material 3 was 13 kg, and the foaming ratio was 4 times.
For example, a red dye was mixed into the injection material 3 as the coloring material 4.

As shown in FIG. 6, a red injection material 3 appeared on the outer surface of the intermediate portion of the simulated ground 30 less than 20 seconds after the injection of the injection material 3 was started. In addition, drainage was actively observed from the ventilation hole 13d. Further, it was confirmed through the transparent body 11 that the injection material 3 penetrated up and down in the simulated ground 30. Diffusion converged in about 120 seconds from the start of injection.
It was confirmed that by coloring the injection material 3, the state of permeation can be clearly observed, and the permeation time, permeation distance, etc. can be clearly measured.

The present invention can be applied to, for example, the selection of a ground improvement material for a tunnel ground.

1 Permeability evaluation test equipment 3 Injection material 4 Coloring material 10 Test container 10a Test room 11 Body 12 Lid 12d Ventilation hole 13 Lid 13d Ventilation hole 14, 15 Filter 20 Injection tube 30 Simulated ground

Claims (7)

It is a test method to evaluate the permeability of foamable injection material into the ground.
The simulated ground is housed in an elongated tubular test container that allows the inside to be seen through, and the injection tube is inserted and placed.
With the test container upright, the injection material is injected into the simulated ground through the opening of the injection pipe via the injection pipe, and the injection material in a liquid state before foaming is mainly diffused and permeated downward. , Diffuse and infiltrate the injection material after foaming mainly upward,
The opening of the injection tube is arranged in the middle portion in the height direction of the test container, and the distance from the opening to the lower end of the test container is downward from the opening of the injection material. A permeability evaluation test method, characterized in that the distance from the opening to the upper end of the test container is larger than the permeation distance of the injection material from the opening to the upper side. The permeability evaluation test method according to claim 1, wherein the injection material is colored. A test device that evaluates the permeability of foamable injection material into the ground.
A test container that is formed in an elongated tubular shape that allows the inside to be seen through, and can be erected while accommodating a simulated ground.
An injection tube that is inserted into the test container and has an opening to inject the injection material from the opening into the simulated ground.
With
The injection material injected into the simulated ground from the opening of the injection pipe mainly diffuses and permeates downward in the liquid state before foaming, and mainly diffuses and permeates upward after foaming.
The opening of the injection tube is arranged in the middle portion in the height direction of the test container, and the distance from the opening to the lower end of the test container is downward from the opening of the injection material. The permeability evaluation test apparatus, which is larger than the permeation distance of the injection material and the distance from the opening to the upper end of the test container is larger than the permeation distance of the injection material from the opening to the upper side. The permeability evaluation test apparatus according to claim 3, wherein the injection material is colored. The inner diameter of the test container is 50 mm to 300 mm.
The permeability evaluation test apparatus according to claim 3 or 4, wherein the height of the test container is larger than the inner diameter and is 300 mm to 2000 mm. Any one of claims 3 to 5, wherein the test container has an elongated tubular body portion made of a translucent material and a lid portion that closes an end portion of the body portion. Permeability evaluation test apparatus according to. The penetration according to claim 6, wherein a ventilation hole is formed in the lid portion, and the ventilation hole is provided with a filter that allows the permeation of gas and liquid and prevents the permeation of solid. Sex evaluation test equipment.

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