JP2019000767A - Well for cleanup and soil cleanup method - Google Patents

Abstract

To provide a well for cleanup which can feed detergent every soil in multiple soil in vertical direction widely at one time.SOLUTION: A well for cleanup 1 to cleanup soil G that multiple soil is laminated in vertical direction, water permeability of the soil neighboring in vertical direction is different each other, and contains pollutant comprises: an outer tube 11 that the bottom end is blocked, multiple external jet holes 11a to spout clarifier L outside are formed along vertical direction, and inserted in a pit G2 formed to the soil; a low water permeability component 26 placed at a position corresponding to a boundary of the soil neighboring in vertical direction between the outside peripheral surface and the inside peripheral surface of the pit; and a high water permeability component 28 placed beside to the low water permeability component in vertical direction between the outside peripheral surface and the inside peripheral surface of the pit and having more permeability than the low water permeability component. The plural of the plural of jet holes are placed to between each low water permeability component neighboring in vertical direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a purification well and a soil purification method.

There are various in-situ purification technologies including bioremediation as a method for purifying soil and groundwater contamination (see, for example, Patent Documents 1 and 2).
Bioremediation is a technology that activates microorganisms in the ground and decomposes and reduces pollutants such as organochlorine compounds using the metabolic function of microorganisms. As a method for activating microorganisms, a method of injecting a purification agent such as a nutrient through a purification well built in the ground is generally used.

Conventionally, when the water permeability of the target soil layer is relatively low (for example, the hydraulic conductivity is 10 ⁻⁴ cm / s or less (centimeter per second) or less), the double packer described in Patent Documents 1 and 2 above is used. The soil purification method used was used. In this soil purification method, a ground improvement method used for the purpose of improving soft ground by injecting a grout material or a caking agent is applied to soil purification.
Since the double packer has been widely used as a ground improvement method, the injection outer pipe (outer pipe) used for the double packer has been standardized and is commercially available. Pumps and other equipment other than double packers can be general-purpose products, not special devices.

For example, a standard injection outer tube has a length of 1 m and an outer diameter of 40 mm. The injection outer tube is made of PVC (polyvinyl chloride) and is provided with a sleeve (outer ejection hole) every 33 cm in the longitudinal direction. The injection inner pipe is provided with packers that swell with air above and below the jet nozzle.
The feature of the double packer is that a fixed amount of the cleaning agent can be injected at a specific depth of the soil, and the pressure injection is performed by pumping.
Therefore, in the soil remediation field, when the water permeability of the target soil layer is low, it is difficult to naturally inject the decontaminant, and therefore, injection by a double packer has been performed.

JP 2010-063978 A Japanese Patent No. 3332600

  However, water permeability and thickness vary depending on the soil layer. When the purification agent is supplied simultaneously to a plurality of soil layers having different water permeability, the purification agent is concentrated and supplied to the soil layer having high water permeability and easy flow of the purification agent. Moreover, if work is performed on a thick soil layer by dividing the depth into several stages, a great deal of labor and time are required.

  This invention is made | formed in view of such a problem, Comprising: In one soil layer of the several soil layer used as the object which supplies a cleaning agent, a cleaning agent is widely spread | vertically at once in the up-down direction. An object is to provide a purification well and a soil purification method that can be supplied.

In order to solve the above problems, the present invention proposes the following means.
The purification well according to the present invention comprises a plurality of soil layers stacked in the vertical direction, and the purification wells for purifying soil containing different pollutants while the water permeability of the soil layers adjacent in the vertical direction are different from each other. And the lower end portion is closed, and a plurality of outer ejection holes for ejecting the purification agent to the outside are formed along the vertical direction, and the outer tube inserted in the vertical hole formed in the soil, Between the outer peripheral surface of the outer tube and the inner peripheral surface of the vertical hole, a low water permeable member disposed at a position corresponding to the boundary portion of the soil layer adjacent in the vertical direction, and the outer peripheral surface of the outer tube And a highly permeable member disposed in a vertical direction with respect to the low water permeable member and having a higher water permeability than the low water permeable member. Between each of the low water permeability members adjacent to each other. More of the outer injection ports is characterized in that it is arranged.

  Further, the soil purification method of the present invention is a soil purification method in which a plurality of soil layers are stacked in the vertical direction, and the soil layers adjacent in the vertical direction have different water permeability and contain soil containing contaminants. An outer tube arranging step of inserting an outer tube having a lower end closed and a plurality of outer ejection holes formed in the vertical direction into a vertical hole formed in the soil, and an outer peripheral surface of the outer tube And a low water permeability member disposed at a position corresponding to a boundary portion of the soil layer adjacent in the vertical direction between the vertical hole and the inner peripheral surface of the vertical hole, and in the vertical direction with respect to the low water permeability member By arranging a highly water permeable member having higher water permeability than the low water permeable member side by side, a plurality of the plurality of outer ejection holes are provided between each of the low water permeable members adjacent in the vertical direction. Before the water-permeable member placement process and the vertical direction A purifying agent is ejected to the outside of the outer pipe from a plurality of the plurality of outer ejection holes arranged between the low water permeable members, and the purifying agent is supplied to the soil layer through the high water permeable member. And a supply process.

According to these inventions, the purifiers ejected from the plurality of outer ejection holes to the outside of the outer tube are less likely to flow through the low water permeability member than within the high water permeability member. For this reason, this purifier flows mainly in the highly permeable member that faces a plurality of the plurality of outer ejection holes without flowing much in the permeable member, and the soil that faces the highly permeable member. Supplied to the layer. Thereby, a purifier is supplied to one soil layer which opposes several of these several external ejection holes among the several soil layers which soil has. Note that in this specification, the term “facing” includes the meaning of contacting.
In addition, since each of the plurality of outer ejection holes is disposed between the low-permeability members adjacent in the vertical direction, the plurality of outer ejection holes can be Purifiers are supplied in a wide range of directions.

  Further, in the purification well, the purification well is attached to the outer pipe, allows the purifier to move from the inside of the outer pipe to the outside through the outer ejection hole, and passes through the outer ejection hole. You may provide the control part which controls the movement of the said purifier from the outside to the inside.

Moreover, in said soil purification method, ^10-4 cm / s or more and ^10-3 cm / s or less of the water permeability coefficient of the said soil layer to which the said purification | cleaning agent is supplied among these soil layers may be sufficient. .
According to this invention, even when the water permeability of the soil layer to which the cleaning agent is supplied is relatively low, the cleaning agent is reliably supplied by using one soil layer for supplying the cleaning agent at a time. can do.

  Further, in the soil purification method, an inner ejection hole is formed after the outer pipe arranging step and before the supplying step, and a pair is arranged so as to sandwich the inner ejection hole in the vertical direction. An inner tube having a sealed portion inserted into the outer tube, and a pair of sealing portions between the inner peripheral surface of the outer tube and the outer peripheral surface of the inner tube, respectively. A sealing step of liquid-tightly sealing and arranging the plurality of outer ejection holes so as to sandwich the plurality of outer ejection holes in the vertical direction by the pair of sealing portions. The purification agent may be ejected from the inner ejection hole to the outside of the inner tube by supplying the purification agent into the pipe.

In the present invention, according to the purification well according to claim 1 and the soil purification method according to claim 3, once for each soil layer among a plurality of soil layers to which the purification agent is supplied. A wide range of purification agents can be supplied vertically.
According to the purification well according to the second aspect, it is possible to suppress the purifying agent ejected to the outside of the outer pipe through the outer ejection hole from returning to the inside of the outer pipe again through the outer ejection hole.

According to the soil purification method of claim 4, even if the water permeability of the soil layer to which the purification agent is supplied is relatively low, the soil layer to which the purification agent is supplied at one time can be The purification agent can be reliably supplied.
According to the soil purification method of Claim 5, since the upper and lower sides of the inner ejection holes are sealed by the pair of sealing portions, a plurality of outer ejection holes sandwiched in the vertical direction by the pair of sealing portions. The purifier can be ejected to the outside of the outer tube through a plurality of them.

It is the figure which fractured | ruptured a part which shows schematic structure of the well for purification | cleaning of one Embodiment of this invention. It is a perspective view of the injection outer tube | pipe of the well for a purification | cleaning. It is a flowchart which shows the soil purification method of one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the soil purification method. It is a longitudinal cross-sectional view which shows the soil purification method. In an Example, it is a top view which shows arrangement | positioning of the well for a purification | cleaning and an observation well. (A) is a longitudinal sectional view showing the structure of the soil, (B) is a longitudinal sectional view showing a schematic structure of the purification well, and (C) is for observation with respect to the depth from the surface of the soil. It is a longitudinal cross-sectional view which shows schematic structure of a well. It is a figure which shows the result of having detected bromine with respect to each soil layer in each observation well.

Hereinafter, an embodiment of a purification well and a soil purification method according to the present invention will be described with reference to FIGS. 1 to 8.
As shown in FIG. 1, the purification well 1 of the present embodiment is for purifying soil G containing pollutants. The soil G is formed by stacking a plurality of soil layers G1A, G1B, G1C, G1D in the vertical direction. In this example, the soil layers G1A, G1B, G1C, and G1D are referred to as a first soil layer G1A, a second soil layer G1B, a third soil layer G1C, and a fourth soil layer G1D in order from the top to the bottom. When the soil layers G1A, G1B, G1C, and G1D are referred to without distinction, they are collectively referred to as a soil layer G1. For example, the soil layer G1 is a layer divided based on a geological division name. For example, the first soil layer G1A is a banking layer. The second soil layer G1B is a sandy soil layer, the third soil layer G1C is a fine sand layer, and the fourth soil layer G1D is a viscous soil layer.
The water permeability of the soil layers G1 adjacent in the vertical direction is different from each other. Specifically, the water permeability becomes lower in the order of the soil layers G1B, G1C, G1D (it is difficult for water to flow inside), and the fourth soil layer G1D is the lowest.

For example, the permeability coefficient of the third soil layer G1C is 10 ⁻⁴ cm / s (centimeter per second) or more and 10 ⁻³ cm / s or less among the soil layers G1A, G1B, and G1C to which the purifying agent described later is supplied. . That is, the hydraulic conductivity of the third soil layer G1C is on the order of 10 ⁻⁴ cm / s. The water permeability coefficient can be measured, for example, by a water level permeability test.

In this example, for example, the contaminant is a cyanide compound. The cyanide is decomposed and purified by microorganisms in the soil G. The more microorganisms in the soil G are activated, the more the microorganisms decompose the pollutants.
The purification agent supplied to the soil layer G1 to activate the microorganisms includes a pH adjuster and high-concentration oxygen water. The pH adjuster is sodium bicarbonate, sodium bicarbonate, citric acid, phosphate, or the like.

The purification well 1 includes an injection outer tube (outer tube) 11, an injection inner tube (inner tube) 16, a low water permeable member 26, and a high water permeable member 28.
The injection outer tube 11 is formed in a tubular shape, and its lower end is closed. The injection outer tube 11 extends along the vertical direction.
As shown in FIGS. 1 and 2, the injection outer tube 11 is formed with a plurality of outer ejection holes 11a for ejecting the cleaning agent to the outside along the vertical direction. The outer ejection hole 11a has a slit shape in which the circumferential length of the injection outer tube 11 is longer than the vertical length. The outer ejection hole 11 a extends from the inner peripheral surface of the injection outer tube 11 to the outer peripheral surface. For example, a pair of outer ejection holes 11 a are formed so as to sandwich the axis C of the outer injection tube 11. The plurality of outer ejection holes 11a are formed to be symmetric with respect to the axis C.

Below, it arrange | positions in the range (position which opposes 1st soil layer G1A via the ring 12 and the highly water-permeable member 28 mentioned later) in which the 1st soil layer G1A exists in an up-down direction among several outer ejection holes 11a. The formed outer ejection hole 11a is also referred to as an outer ejection hole 11aA. Similarly, an outer ejection hole 11aB for the second soil layer G1B and an outer ejection hole 11aC for the third soil layer G1C are respectively defined.
The injection outer tube 11 may be formed with an outer ejection hole 11a only on one side with respect to the axis C.

A plurality of rings (regulators) 12 are attached to the outer peripheral surface of the injection outer tube 11 so as to cover the outer ejection holes 11a. The ring 12 is made of an elastic material such as resin.
When the ring 12 receives a pressure radially outward from the inner peripheral surface side, the ring 12 is elastically deformed radially outward and is separated from the outer peripheral surface of the injection outer tube 11. Accordingly, the ring 12 allows the purifier to move from the inside of the injection outer tube 11 to the outside through the outer ejection hole 11a. On the other hand, when the ring 12 receives a pressure radially inward from the outer peripheral surface side, the ring 12 is restored and deformed radially inward and is pressed against the opening peripheral edge of the outer ejection hole 11 a on the outer peripheral surface of the injection outer tube 11. Thereby, the ring 12 regulates the movement of the purifier from the outside to the inside of the injection outer tube 11 through the outer ejection hole 11a.
The injection outer tube 11 to which the plurality of rings 12 are attached is inserted into a vertical hole G2 formed in the soil G.

As shown in FIG. 1, the injection inner tube 16 is formed in a tubular shape, and its lower end is closed. The injection inner tube 16 extends along the vertical direction. The outer diameter of the inner injection tube 16 is smaller than the inner diameter of the outer injection tube 11.
A plurality of inner ejection holes 16a for ejecting the purifier to the outside are formed in the lower end portion of the injection inner pipe 16 along the vertical direction. In this example, the two inner ejection holes 16a are formed in the injection inner pipe 16, but the number of the inner ejection holes 16a formed in the injection inner pipe 16 is not limited to this and may be one, There may be more than one. The inner ejection hole 16a extends from the inner peripheral surface of the injection inner tube 16 to the outer peripheral surface.

A pair of sealing portions 17 are disposed on the outer peripheral surface of the injection inner tube 16 so as to sandwich the plurality of inner ejection holes 16a in the vertical direction. The sealing part 17 is formed in an annular bag shape. The sealing part 17 is connected to an air supply / discharge device (not shown). For example, an air pump or the like is used for the air supply / discharge device. The air supply / discharge device can supply and discharge air. When the air supply / discharge device supplies air into the sealing portion 17, the sealing portion 17 expands, so that the space between the inner peripheral surface of the injection outer tube 11 and the outer peripheral surface of the injection inner tube 16 is liquid-tightly sealed. The sealed state is stopped. On the other hand, when the air supply / discharge device exhausts air from the inside of the sealing portion 17, the sealing portion 17 contracts, so that the sealing portion 17 is separated from the inner peripheral surface of the injection outer tube 11, and the sealing is performed. It becomes the released release state. The configuration in which the upper and lower sides of the plurality of inner ejection holes 16a are sealed with a pair of sealing portions 17 is also called a double packer.
The inner peripheral surface of the upper end portion of the injection outer tube 11 and the outer peripheral surface of the injection inner tube 16 are preferably sealed with a known sealing material 18.

For example, the upper end portion of the injection inner pipe 16 is connected to the purifier supply / discharge device 20 via the flexible pipe 19.
The shape of the flexible tube 19 can be changed in accordance with the movement of the injection inner tube 16 along the vertical direction.
For example, a liquid transfer pump or the like is used for the purifier supply / discharge device 20. The cleaning agent supply / discharge device 20 can supply the cleaning agent L in the housing part 21 to the outside, or suck the external cleaning agent L into the housing part 21. In addition, as the cleaning agent supply / discharge device 20, a cleaning agent supply device that can supply the cleaning agent L but cannot suck the cleaning agent L may be used.

For example, bentonite is used for the low water permeability member 26. The low water permeability member 26 is formed in a tubular shape, and is disposed at a position corresponding to a boundary portion between the soil layers G1 adjacent in the vertical direction between the outer peripheral surface of the outer injection pipe 11 and the inner peripheral surface of the vertical hole G2. ing. The boundary part of soil layer G1 adjacent to the up-down direction here means the range including the boundary of soil layer G1 adjacent to the up-down direction and the range including the vicinity of this boundary in the up-down direction.
The low water permeability member 26 is in contact with the outer peripheral surface of the outer injection pipe 11 and the soil layer G1.
Hereinafter, the low water permeable member 26 disposed at a position corresponding to the boundary between the first soil layer G1A and the second soil layer G1B is also referred to as a low water permeable member 26A. Similarly, the low water permeable member 26 disposed at a position corresponding to the boundary between the second soil layer G1B and the third soil layer G1C is also referred to as a low water permeable member 26B.
In addition, the low water permeability member 26 may be arrange | positioned in the position corresponding to the boundary part of 3rd soil layer G1C and 4th soil layer G1D.

A plurality of outer ejection holes 11a are disposed between the low water permeability members 26 adjacent in the vertical direction. Specifically, four outer ejection holes 11aB are disposed between the low water permeability member 26A and the low water permeability member 26B. Of the four outer ejection holes 11aB, two are disposed on one side of the axis C and the remaining two are disposed on the other side of the axis C. On each side of the axis C, two outer ejection holes 11aB are formed along the vertical direction.
The number of outer ejection holes 11aB is not limited to four. It suffices that at least two outer ejection holes 11aB are arranged in the vertical direction.
In the present embodiment, the four outer ejection holes 11aC, which are a plurality of the outer ejection holes 11a, are also provided below the low water permeability member 26B, which is the low water permeability member 26 disposed at the lowermost position. It is arranged. For example, of the 10 outer spray holes 11a formed in total, two are disposed as outer spray holes 11aA at positions facing the first soil layer G1A. Similarly, four are arranged as outer ejection holes 11aB at positions facing the second soil layer G1B, and four are disposed as outer ejection holes 11aC at positions facing the third soil layer G1C.

  The highly water permeable member 28 has higher water permeability than the low water permeable member 26. For example, No. 3 silica sand is used for the highly permeable member 28. The particle size (particle size) of No. 3 silica sand is distributed mainly in the range of about 1 to 2 mm. The highly water permeable member 28 is formed in a tubular shape, and is arranged in the vertical direction with respect to the low water permeable member 26 between the outer peripheral surface of the injection outer tube 11 and the inner peripheral surface of the vertical hole G2. That is, the highly water permeable member 28 and the low water permeable member 26 are alternately arranged in the vertical direction with no gap therebetween. The highly permeable member 28 is in contact with the outer peripheral surface of the outer injection pipe 11 and the soil layer G1.

Next, the soil purification method of this embodiment using the purification well 1 configured as described above will be described. FIG. 3 is a flowchart showing the soil purification method S of the present embodiment.
First, in position detection process S1, an operator performs well-known boring investigation with respect to soil G. FIG. Thereby, the position of the boundary of the soil layer G1 adjacent to the up-down direction, that is, the depth from the surface of the soil G is detected. If a boring survey has been performed in advance and the boundary depth is known, this position detection step S1 may not be performed. When the position detection step S1 is completed, the process proceeds to the outer tube placement step S3.

  Next, in the outer tube placement step S3, as shown in FIG. 4, the injection outer tube 11 to which the plurality of rings 12 are attached is inserted into the vertical hole G2 formed in the soil G. The vertical hole G2 can be formed by a known drilling machine such as a boring machine. The inner diameter of the vertical hole G2 is, for example, 86 mm or 100 mm.

Next, in the water permeable member disposing step S5, the low water permeable property is located at a position corresponding to the boundary portion of the soil layer G1 adjacent in the vertical direction between the outer peripheral surface of the injection outer tube 11 and the inner peripheral surface of the vertical hole G2. The member 26 is disposed, and the highly water permeable member 28 is disposed in the vertical direction with respect to the low water permeable member 26. That is, the highly water permeable member 28 and the low water permeable member 26 are alternately arranged in the vertical direction with no gap therebetween.
A plurality of the outer ejection holes 11a are disposed between the low water permeability members 26 adjacent in the vertical direction. Specifically, four outer ejection holes 11aB among the ten outer ejection holes 11a are disposed between the low water permeability member 26A and the low water permeability member 26B. In this example, two outer ejection holes 11aA among the ten outer ejection holes 11a are disposed above the low water permeability member 26A. Four outer ejection holes 11aC among the ten outer ejection holes 11a are disposed below the low water permeability member 26B.

Next, in the inner tube arranging step S7, as shown in FIG. 1, the injection inner tube 16 is inserted into the injection outer tube 11 from above the injection outer tube 11. In addition, before inserting the injection | pouring inner pipe | tube 16 in the injection | pouring outer pipe | tube 11, it is preferable to make a pair of sealing parts 17 into a cancellation | release state with an air supply / discharge device. The space between the inner peripheral surface of the upper end portion of the injection outer tube 11 and the outer peripheral surface of the injection inner tube 16 is sealed with a sealing material 18.
Next, in sealing process S9, air is supplied to a pair of sealing parts 17 with an air supply / exhaust apparatus, and a pair of sealing parts 17 is made into a sealing state. At this time, the pair of sealing portions 17 are arranged so as to sandwich the plurality of outer ejection holes 11aC among the plurality of outer ejection holes 11a in the vertical direction.

Next, in the supply step S11, the purification agent L is supplied from the purification agent supply / discharge device 20 and the purification agent L is supplied into the injection inner pipe 16, whereby the purification agent L is injected into the injection holes 16a. It is ejected to the outside of the pipe 16.
In addition, even if the purifier L ejected from the plurality of inner ejection holes 16a attempts to flow further above the sealing portion 17 disposed above the plurality of inner ejection holes 16a, the outer injection pipe 11 and the inner injection pipe Since the space between 16 and 16 is liquid-tightly sealed from the sealing portion 17, the purifier L is less likely to flow further upward than the sealing portion 17. Similarly, even if the purifier L ejected from the plurality of inner ejection holes 16a flows further below the sealing portion 17 disposed below the plurality of inner ejection holes 16a, Since the space between the pipe 16 is liquid-tightly sealed, the purifier L is less likely to flow further downward than the sealing portion 17.
Then, the purification agent L is ejected from the plurality of outer ejection holes 11aC among the plurality of outer ejection holes 11a to the outside of the injection outer tube 11, and the purification agent L is supplied to the third soil layer G1C through the high water permeability member 28. .

The purifier L ejected from the plurality of outer ejection holes 11 a C to the outside of the injection outer tube 11 is less likely to flow through the low water permeable member 26 than within the high water permeable member 28. For this reason, the purifier L flows mainly in the highly water permeable member 28 facing the plurality of outer ejection holes 11aC and does not flow so much in the low water permeable member 26B, and faces the highly water permeable member 28. Supplied to the third soil layer G1C. At this time, since the purification agent L is difficult to be supplied to the second soil layer G1B by the low water permeability member 26B, the supply capacity of the purification agent L by the purification agent supply / discharge device 20 can be concentrated on the third soil layer G1C. Therefore, the purification agent L can be supplied to the third soil layer G1C using the purification agent supply / discharge device 20 having a smaller supply capacity.
When the supply step S11 ends, the process proceeds to the sealing release step S13.

  When the purification agent L is supplied to the third soil layer G1C, the microorganisms in the third soil layer G1C are activated by the pH adjuster and the high-concentration oxygen water contained in the purification agent L. Contaminants in the third soil layer G1C are decomposed by the activated microorganisms.

Next, in sealing release process S13, a pair of sealing part 17 is made into a cancellation | release state with an air supply / discharge device. Before the pair of sealing portions 17 are released, the cleaning agent L is sucked by the cleaning agent supply / discharge device 20 so that the pair of seals is provided between the injection outer tube 11 and the injection inner tube 16. The purifier L between the portions 17 may be moved into the accommodating portion 21 via the flexible pipe 19.
Next, in step S15, the operator determines whether or not to supply the purifier L to other soil layers G1 other than the third soil layer G1C.
When it is determined in step S15 that the purifier L is supplied to the soil layer G1 other than the third soil layer G1C (Yes), the process proceeds to the moving step S17. On the other hand, when it is determined in step S15 that the purifier L is not supplied to other soil layers G1 other than the third soil layer G1C (No), all the steps of the soil purification method S are finished.

In the moving step S17 transferred from step S15, the injection inner tube 16 is moved upward with respect to the injection outer tube 11, as shown in FIG. At this time, the pair of sealing portions 17 are arranged so as to sandwich the plurality of outer ejection holes 11aB among the plurality of outer ejection holes 11a in the vertical direction.
Next, sealing process S9 and supply process S11 are performed.
In the supply step S11, the cleaning agent L is ejected to the outside of the injection outer tube 11 from the plurality of outer ejection holes 11aB disposed between the low water permeability members 26A and 26B adjacent in the vertical direction, and the high water permeability member 28 is obtained. Through the second soil layer G1B.

As described above, the movement process S17 to the sealing release process S13 are repeated according to the number of soil layers G1 supplying the purification agent L, and all the processes of the soil purification method S are completed.
In addition, the order which performs water-permeable member arrangement | positioning process S5 and inner pipe arrangement | positioning process S7 is not limited to this.

(Example)
Hereinafter, examples (and comparative examples) of the present invention will be specifically described and described in detail. However, the present invention is not limited to the following examples.
In this embodiment, as shown in FIG. 6, the purification well 1 is arranged so as to be surrounded by four observation wells 2. The four observation wells 2 are arranged around the purification well 1 at substantially equal angles. For example, the distance r between each observation well 2 and the purification well 1 is 1.0 m.
These four observation wells 2 may be distinguished from observation wells 2A, 2B, 2D, and 2C in a counterclockwise direction in plan view.

FIG. 7A shows a schematic configuration of the soil G together with the depth from the surface of the soil G.
7B shows a schematic configuration of the purification well 1 and FIG. 7C shows a schematic configuration of the observation well 2. The depths of (A), (B), and (C) in FIG. 7 correspond to each other.
In this example, as shown in FIG. 7A, the first soil layer G1A is a clay layer, and the thickness of the first soil layer G1A is 1.5 m. The second soil layer G1B is a silt-mixed sand layer, and the thickness of the second soil layer G1B is 1.0 m. The third soil layer G1C is a fine sand layer, and the thickness of the third soil layer G1C is 1.0 m. The fourth soil layer G1D is a fine sandstone layer.

The purification well 1 in FIG. 7B does not show the ring 12, but shows the shape of the outer ejection hole 11a.
The low water permeability member 26A is disposed at a position corresponding to a boundary portion between the first soil layer G1A and the second soil layer G1B. Specifically, the low water permeability member 26 </ b> A is disposed from the surface of the soil G to a position at a depth of 1.1 m to a position at a depth of 1.3 m. The low water permeability member 26B is disposed at a position corresponding to a boundary portion between the second soil layer G1B and the third soil layer G1C. Specifically, the low water permeability member 26 </ b> B is disposed from the surface of the soil G to a depth of 2.4 m to a depth of 2.6 m.

  In the outer injection pipe 11, there is a non-porous pipe region R <b> 1 in which the outer ejection hole 11 a is not formed above the outer ejection hole 11 a disposed at the uppermost position. In the vertical direction, a region where the plurality of outer ejection holes 11aB are formed is a double packer region R2 that is sealed in the vertical direction by the pair of sealing portions 17. A non-porous tube region R3 in which the outer ejection hole 11a is not formed is below the outer ejection hole 11aB disposed at the lowermost position and above the outer ejection hole 11aC disposed at the uppermost position. is there. In the vertical direction, a region in which the plurality of outer ejection holes 11aC is formed is a double packer region R4 that is sealed in the vertical direction by the pair of sealing portions 17. The lower end of the double packer region R4 extends to a depth of 3.5 m.

The observation well 2 in FIG. 7C includes a first observation tube 31, a second observation tube 32, a low water permeability member 26, and a high water permeability member 28.
The lower ends of the first observation tube 31 and the second observation tube 32 are closed.
At the lower end of the first observation tube 31, there is a perforated tube region R6 in which many small holes are formed. The perforated pipe region R6 extends from a position having a depth of 3.0 m corresponding to the lower half of the third soil layer G1C to a position having a depth of 3.5 m. The portion other than the perforated tube region R6 in the first observation tube 31 is a non-porous tube region R7 in which no hole is formed.
At the lower end of the second observation tube 32, there is a perforated tube region R8 in which many small holes are formed. The perforated pipe region R8 extends from a position having a depth of 1.4 m substantially corresponding to the second soil layer G1B to a position having a depth of 2.4 m. The portion other than the perforated tube region R8 in the second observation tube 32 is a non-porous tube region R9 where no hole is formed.

The low water permeability member 26 and the high water permeability member 28 of the observation well 2 are disposed at the same depth as the low water permeability member 26 and the high water permeability member 28 of the purification well 1.
The first observation tube 31 is used for detection of the purifier L in the third soil layer G1C. The second observation tube 32 is used to detect the purifier L in the second soil layer G1B.

Whether or not the cleaning agent L supplied from the purification well 1 is detected in each observation well 2 using the purification well 1 and the four observation wells 2 in the soil G configured as described above. An experiment was conducted to investigate whether or not. As the cleaning agent L, an aqueous potassium bromide solution in which 200 mg of potassium bromide was dissolved in 1 L (liter) of water was used as ground water and a racer. Since potassium was contained in the soil G, it was investigated whether bromine was detected in each observation well 2.
Before supplying the cleaning agent L, bromine was not detected in each observation well 2.
In each observation well 2, the results of detecting bromine in the soil layers G1B and G1C are shown in Table 1 and FIG. In Table 1 and FIG. 8, the unit of bromine is mg / L (milligram per liter). In FIG. 8, the detected result is displayed logarithmically.

In each observation well 2, it was found that bromine was detected in the soil layers G1B and G1C.
As described above, the low water-permeable member 26 is disposed at a position corresponding to the boundary portion of the soil layer G1 adjacent in the vertical direction, and the cleaning agent L is injected by the double packer for each soil layer G1. It was found that osmotic injection was possible in the target soil layer G1.

As described above, according to the purification well 1 and the soil purification method S of the present embodiment, the purification jetted out of the injection outer tube 11 from the plurality of outer ejection holes 11aB among the plurality of outer ejection holes 11a. The agent L is less likely to flow in the low water permeability member 26 than in the high water permeability member 28. For this reason, the purifier L flows mainly in the high water permeable member 28 facing the plurality of outer ejection holes 11aB and does not flow so much in the low water permeable member 26, and faces the high water permeable member 28. Supplied to the second soil layer G1B. Thereby, the purifier L is supplied to 2nd soil layer G1B which opposes these some outer ejection holes 11aB among the some soil layers G1 which the soil G has.
In addition, since the plurality of outer ejection holes 11aB are disposed between the low water permeability members 26 adjacent in the vertical direction, the plurality of outer ejection holes 11aB allow the purifier L to spread widely in the vertical direction at once. Supplied.
From the above, the purification agent L can be widely supplied in the vertical direction at a time for each soil layer G1 of the plurality of soil layers G1 to be supplied with the purification agent L.

  By the purification well 1 and the soil purification method S of this embodiment, the construction efficiency (supply efficiency) of the purification agent L can be significantly improved. Injecting a certain amount of the purifier L into each soil layer G1 can be performed with high efficiency.

The purification well 1 includes a ring 12. Thereby, it is possible to suppress the purifier L sprayed to the outside of the injection outer tube 11 through the outer ejection hole 11a from returning to the inside of the injection outer tube 11 again through the outer ejection hole 11a.
The water permeability coefficient of the soil layer G1 to which the purifier L is supplied is 10 ⁻⁴ cm / s or more and 10 ⁻³ cm / s or less. Thus, even when the water permeability of the soil layer G1 to which the purification agent L is supplied is relatively low, the purification agent L can be reliably obtained by using one soil layer G1 to supply the purification agent L at a time. Can be supplied to.
In the soil purification method S, an inner pipe arranging step S7 and a sealing step S9 are performed. Since the upper and lower sides of the inner ejection holes 16a are sealed by the pair of sealing portions 17, the purifier L is passed through a plurality of the plurality of outer ejection holes 11a sandwiched by the pair of sealing portions 17 in the vertical direction. It can be ejected outside the injection outer tube 11.

As mentioned above, although one embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and modifications, combinations, and deletions within a scope that does not depart from the gist of the present invention. Etc. are also included.
For example, in the above embodiment, the purification well 1 does not have to include the ring 12 when the purification agent L is continuously supplied by the purification agent supply / discharge device 20.
The hydraulic conductivity of the soil layers G1A, G1B, G1C may be larger than 10 ⁻³ cm / s. For such a soil layer G1 in which water easily flows, the purification well 1 and the soil purification method S of the present embodiment can be suitably used.

1 Well for purification 11 Outer pipe (outer pipe)
11a Outlet hole 12 Ring (Regulator)
26 Low water permeability member 28 High water permeability member G Soil G1A First soil layer (soil layer)
G1B Second soil layer (soil layer)
G1C 3rd soil layer (soil layer)
G1D 4th soil layer (soil layer)
G2 Vertical hole L Cleaner S Soil purification method S3 Outer tube placement step S5 Permeable member placement step S7 Inner tube placement step S9 Sealing step S11 Supply step

Claims (5)

A plurality of soil layers are stacked in the vertical direction, the water permeability of the soil layers adjacent in the vertical direction are different from each other and a purification well for purifying soil containing contaminants,
The lower end is closed, and a plurality of outer ejection holes for ejecting the cleaning agent to the outside are formed along the vertical direction, and the outer tube inserted in the vertical hole formed in the soil,
Between the outer peripheral surface of the outer pipe and the inner peripheral surface of the vertical hole, a low water permeable member disposed at a position corresponding to the boundary portion of the soil layer adjacent in the vertical direction,
A highly permeable member disposed between the outer peripheral surface of the outer tube and the inner peripheral surface of the vertical hole in the vertical direction with respect to the low water permeable member, and having a higher water permeability than the low water permeable member; ,
With
A purification well, wherein a plurality of the plurality of outer ejection holes are disposed between the low water permeability members adjacent in the vertical direction.   The purifier is attached to the outer pipe, allows the purifier to move from the inside of the outer pipe to the outside through the outer jet hole, and passes through the outer jet hole from the outside to the inside of the outer pipe. The purification well according to claim 1, further comprising a restriction unit that restricts movement. A soil purification method in which a plurality of soil layers are stacked in the vertical direction, and the soil layers adjacent to each other in the vertical direction have different water permeability and purify soil containing contaminants,
An outer tube disposing step in which a lower end is closed and an outer tube having a plurality of outer ejection holes formed in the vertical direction is inserted into a vertical hole formed in the soil,
Between the outer peripheral surface of the outer pipe and the inner peripheral surface of the vertical hole, a low water permeable member is disposed at a position corresponding to a boundary portion of the soil layer adjacent in the vertical direction, and the low water permeable member By arranging a highly water permeable member having a higher water permeability than the low water permeable member in the vertical direction, the plurality of outer jets are respectively provided between the low water permeable members adjacent in the vertical direction. A water permeable member disposing step of disposing a plurality of holes;
A purifying agent is jetted out of the outer pipe from a plurality of the plurality of outer jet holes arranged between the low water permeability members adjacent in the vertical direction, and is passed through the high water permeability member to the soil layer. A supplying step of supplying the purifier;
Soil purification method characterized by performing. The soil according to claim 3, wherein a permeability coefficient of the soil layer to which the purification agent is supplied among the plurality of soil layers is 10 ⁻⁴ cm / s or more and 10 ⁻³ cm / s or less. Purification method. After the outer tube arranging step and before the supplying step,
An inner pipe disposing step of inserting an inner pipe having a sealing portion formed so as to sandwich the inner jet hole in the up-down direction and having an inner pipe formed in the outer pipe;
The pair of sealing portions liquid-tightly seal between the inner peripheral surface of the outer tube and the outer peripheral surface of the inner tube, and among the plurality of outer ejection holes by the pair of sealing portions A sealing step of arranging a plurality of
And
5. The soil purification according to claim 3, wherein, in the supplying step, the purification agent is supplied into the inner pipe so that the purification agent is ejected from the inner ejection hole to the outside of the inner pipe. Method.

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