JPH0947737A - Impervious wall and its building method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the building cost of impervious walls and to shorten a work period by building double walls so as to enclose a storage space and successively forming monitoring regions where the lifting of the leaching water from the inside walls is possible and a guiding region where the leaching water from the inside walls is guided to these monitoring regions in the hollow space between the perpendicular walls. SOLUTION: The impervious walls 4 are so built as to enclose the storage space 3 of a waste plant 1 for storing contaminated materials 2, such as harmful waste. The impervious walls 4 are penetrated and formed down to the impermeable layers or hardly permeable layers 5. Water collecting and draining pipes 6 are laid in the storage space 3 and the water gathered by the water collecting and draining pipes 6 is lifted by the pump 7 and is further sent via a water feed pipe 8 to water treatment facilities, by which the water level of the storage space 3 is maintained at a specified level. The impervious walls 4 are built as double walls consisting of inside walls 9 and outside walls 10. The nearly cylindrical monitoring regions 11 and trench-shaped guide regions 12 communicating therewith are formed in the hollow space between the two walls.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impermeable wall installed so as to surround a storage space for storing pollutants such as hazardous waste and a method for constructing the same.

[0002]

2. Description of the Related Art The final disposal of waste is mainly carried out in the form of landfill or surface landfill, and is classified into a barrier-type repository, a stable repository, a managed repository, etc. according to the type of waste. To be done. Of these, the interception-type disposal site is generally constructed by digging down the ground to form a storage space and constructing a concrete impermeable wall around it.

The impermeable wall is formed by using concrete of a predetermined strength to penetrate into an impervious layer or an impermeable layer, and it is considered that harmful pollutants do not diffuse from the waste in the storage space to the surroundings. ing. In addition, in preparation for the unforeseen event of internal contaminants leaching out through cracks in the impermeable wall, we are continuously monitoring the leachate outside the impermeable wall. If a leak of pollutants is found, the work to repair the impermeable wall will be carried out immediately.

[0004]

However, if the pollutants leached to the outside of the impermeable wall diffuse into the surrounding area instead of staying at a predetermined location, it may not be possible to monitor the leached water with sufficient accuracy. Therefore, the applicant has developed a technique in which the impermeable wall is a double wall and the leachate accumulated in the inner space of the double wall is monitored.

However, the construction of the double wall is costly and the construction period is long, and there is a new problem that the construction space for forming the double wall cannot be secured due to the restriction of the site. .

Further, when the leaching of the pollutant occurs at a position away from the monitoring position, it may be overlooked.

The present invention has been made in consideration of the above-mentioned circumstances, and provides a method of constructing an impermeable wall which can reduce the construction cost of the impermeable wall, shorten the construction period, and reduce the construction space. The purpose is to do.

Another object of the present invention is to provide an impermeable wall capable of monitoring the leaching of pollutants in a wide range.

[0009]

In order to achieve the above-mentioned object, the impermeable wall according to the present invention has the following structure.
A double wall composed of an outer wall and an inner wall is constructed so as to surround a storage space for storing pollutants, and a monitoring area capable of pumping the leachate from the inner wall and the inner wall in the hollow space between the double walls. It is formed so as to communicate with a guide region for guiding the leachate to the monitoring region.

The impermeable wall according to the present invention is such that the guiding region is filled with a drain material such as crushed stone or gravel.

According to the third aspect of the present invention, there is provided a method of constructing an impermeable wall, wherein an underground continuous wall is constructed so as to surround a storage space for storing contaminants, and then the underground wall is constructed. A monitoring region in which a double wall consisting of an inner wall and an outer wall is formed by cutting the inside of the continuous wall, and the leachate from the inner wall can be pumped into the hollow space between the double walls, and the leachate from the inner wall is the monitoring region. It forms a communication with a guiding region for guiding to.

In the impermeable wall according to the present invention, when water contaminated with pollutants such as hazardous waste leaches into the hollow space between the double walls via cracks in the inner wall, the leached water is Leach into either the monitoring area or the guidance area. Then, the water leached into the guide area is guided to the monitoring area communicating with the guide area. Therefore, even if a crack or the like is generated on the inner wall at a location distant from the monitoring area, there is no risk of overlooking the occurrence of the crack.

Here, when the drainage material such as crushed stone or gravel is filled in the guiding area, it is possible to support the earth pressure from the inner wall and the outer wall while guiding the leachate to the monitoring area.

Further, in the method of constructing an impermeable wall according to the present invention, first, a normal underground continuous wall is constructed, and then the underground continuous wall is cut by a predetermined excavator to form a double wall. To do. Therefore, compared with the case of constructing a double wall by repeating the construction of the underground wall twice, the cost and the construction period can be reduced, and the wall thickness of the double wall can be reduced.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a water-impermeable wall and a method for constructing the same according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a diagram showing an example in which the impermeable wall according to the present invention is applied to an impermeable wall of a waste disposal site, (a) is an overall schematic view of the waste disposal site, and (b) is Is a vertical cross section of the impermeable wall,
Similarly, (c) is a plan view of the impermeable wall. As can be seen from these figures, the impermeable wall 4 according to the present embodiment is constructed so as to surround the storage space 3 of the waste disposal site 1 that stores the pollutant 2 such as hazardous waste. The impermeable wall 4 is formed so as to penetrate to the impermeable layer or the impervious layer 5. In addition,
A collection / drainage pipe 6 is laid at a predetermined position in the storage space 3, and water collected by the collection / drainage pipe 6 is pumped up by a pump 7,
Further, the water level in the storage space 3 is maintained at a constant level by sending it to a water treatment facility (not shown) via the water supply pipe 8.

The impermeable wall 4 is constructed as a double wall consisting of an inner wall 9 and an outer wall 10. In the hollow space between the double walls, a substantially cylindrical monitoring region 11 and a trench-shaped communicating with it are formed. A guide region 12 is formed.

Here, the guiding region 12 is filled with crushed stones 13 as a drain material so that the leachate from the inner wall 9 is guided to the monitoring region 11 and the earth pressure from the inner wall 9 and the outer wall 10 is supported. It is like this. In addition, a predetermined water gradient is attached to the bottom surface of the guiding region 12,
It is preferable that the leachate is easily guided to the monitoring area 11.

On the other hand, a pumping pump 14 is installed at the bottom of the monitoring area 11 so that the leachate from the inner wall 9 collected from the guiding area 12 or the monitoring area 11 itself is pumped to the ground.

A water supply pump 15 is provided above the impermeable wall 4.
A hollow space between the inner wall 9 and the outer wall 10,
That is, by filling the monitoring area 11 and the guidance area 12 with water and maintaining the water level higher than the water level in the storage space 3 as shown in FIG. It is designed to prevent it from leaching into the hollow space through.

When performing monitoring on the impermeable wall 4 according to this embodiment, the pumping pump 14 is operated in advance to drain water from the hollow space as shown in FIG. 2 (a), if necessary. deep.

Here, if a crack or the like is generated on the inner wall 9, the water contaminated with the pollutant 2 in the waste will leach into the hollow space between the double walls through the crack or the like. The leachate is leached into either the monitoring area 11 or the guidance area 12 as shown in FIGS. 2 (b) and 2 (c),
The water that has leached into the guiding region 12 is guided to the monitoring region 11 that communicates with it.

Next, the water collected in the monitoring area 11 is pumped by the pump 14, and a predetermined water quality test is performed to check the leaching status of pollutants. Then, if a pollutant is confirmed, a damaged portion such as a crack occurring on the inner wall 9 near the monitoring area 11 is identified and repaired.

Next, the procedure for constructing the water shield wall 4 according to this embodiment will be described with reference to FIGS. To construct the impermeable wall 4, first, as shown in FIG. 3 (a), the underground continuous wall 21 is formed so as to surround the storage space 3 for storing waste.
To build. The underground continuous wall 21 may be replaced by concrete after excavation of muddy water, or by a method using a self-hardening stabilizing liquid, but in any case, it reaches the hardly permeable layer or the impermeable layer 5.

Next, as shown in FIG. 3 (b), the underground continuous wall 2
1 is cut to form a double wall consisting of an inner wall 9 and an outer wall 10, and a monitoring region 11 is provided in a hollow space between the double walls.
And the guide region 12 is formed to communicate with each other. For such cutting, for example, a thin water cut wall excavator in which a pair of rotary excavating bits are arranged to face each other and a pair of chain cutters are provided between the bits may be used. When using a thin still water wall excavator, first install the excavator in the underground wall 21.
Then, a pair of excavation bits having a diameter of several tens of centimeters are rotated while gradually suspending the suspension, and the cylindrical monitoring area 11 is excavated in advance. If the monitoring area 11 has been excavated to a certain depth, in addition to this excavation work, it is sufficient to excavate the trench-shaped guide area 12 with the above-mentioned chain cutter.

As shown in FIG. 3 (b), the monitoring area 1
When the excavation of 1 and the guiding region 12 is completed, the same procedure is repeated in sequence to make the hollow space continuous as shown in FIG. 3 (c). In addition, in such a repetition, in FIG.
It is advisable to use the so-called hollowing-out method in which the state shown in (b) is taken as one panel, which is successively drilled one by one in sequence, and the remaining portion is drilled backward.

Next, as shown in FIG. 4 (a), the guiding area 1
The crushed stone 13 is filled in 2 to complete the impermeable wall 4. When filling crushed stones, it is preferable to insert a hollow pipe having an outer diameter substantially equal to or slightly smaller than the inner diameter of the monitoring area 11 into the monitoring area 11 in advance so that the crushed stones 13 do not enter the monitoring area 11. . Also,
After filling with crushed stone, it is preferable to appropriately compact the pressure if necessary.

Finally, as shown in FIG. 4 (b), the pumping pump 14 is installed at the bottom of the monitoring area 11.

As described above, according to the impermeable wall according to the present embodiment, the leachate from the storage space seeps into either the monitoring area 11 or the guiding area 12.
Then, the water leached into the guide region 12 is
Is guided to the monitoring area 11 communicating with. Therefore, even if a crack or the like occurs on the inner wall at a location distant from the monitoring area 11, there is no risk of overlooking the occurrence of the crack, and the range of monitoring is expanded as compared with the conventional method, and surface monitoring is possible. Becomes

Further, since the drainage material such as crushed stone or gravel is filled in the guiding area, it is possible to support the earth pressure from the inner wall and the outer wall while guiding the leachate to the monitoring area.

Further, according to the method of constructing the impermeable wall according to the present invention, since the construction of the underground continuous wall is required only once, the cost can be reduced as compared with the case of constructing the double wall by repeating this twice. It is possible to reduce and shorten the construction period, and it is possible to reduce the wall thickness of the double wall.

In the present embodiment, the monitoring area and the guiding area have been described as being formed over the entire circumference of the underground wall, but when it is sufficient to partially monitor the leachate, for example, on the downstream side of groundwater. In the case of monitoring only one, it is not necessary to provide the monitoring area and the guidance area all around. Even in such a configuration, it is possible to perform planar monitoring in the range where the monitoring area and the guidance area are provided. Even if such a region is not provided over the entire circumference, it can be added at any desired position at any time in the form of additional work.

In the present embodiment, the guide area is filled with crushed stone in consideration of earth pressure support. However, if the steel frame is used to support earth pressure, for example, the guide area is drained. It is not necessary to fill the material and may be left as it is.

[0034]

As described above, the impermeable wall according to the present invention constructs a double wall consisting of an outer wall and an inner wall so as to surround a storage space for storing contaminants, and the space between the double walls. Since the monitoring area capable of pumping the leachate from the inner wall and the guiding area for guiding the leachate from the inner wall to the monitoring area are formed in communication with each other in the hollow space, it is possible to monitor the infiltration of pollutants over a wide range. it can.

The method of constructing the impermeable wall according to the present invention is
The underground continuous wall is constructed so as to surround the storage space for storing the pollutant, and then the inside of the underground continuous wall is cut to form a double wall composed of an inner wall and an outer wall, and a hollow between the double walls. Since the monitoring area capable of pumping the leachate from the inner wall and the guiding area for guiding the leachate from the inner wall to the monitoring area are formed in communication with each other in the space, the construction cost of the impermeable wall is reduced and the construction period is shortened. At the same time, the construction space can be reduced.

[0036]

[Brief description of drawings]

FIG. 1 is a view showing an impermeable wall according to the present embodiment,
(a) is an overall schematic view of the waste disposal site, (b) is a vertical sectional view of the impermeable wall, and (c) is a plan view of the impermeable wall.

2A and 2B are explanatory views for explaining the action of the impermeable wall according to the present embodiment, where FIG. 2A is a vertical sectional view, FIG. 2B is a plan view, and FIG.
A vertical cross-sectional view taken along the line AA of FIG.

FIG. 3 is a perspective view showing a procedure for constructing a water barrier according to the present embodiment.

FIG. 4 is a perspective view showing a procedure for constructing the water impermeable wall according to the present embodiment.

[Explanation of symbols]

 1 Waste Disposal Site 3 Storage Space 4 Impermeable Wall 9 Inner Wall 10 Outer Wall 11 Monitoring Area 12 Guidance Area 13 Crushed Stone (Drain Material)

Claims (3)

[Claims] 1. A monitoring region in which a double wall composed of an outer wall and an inner wall is constructed so as to surround a storage space for storing pollutants, and a leachate from the inner wall can be pumped into a hollow space between the double walls. A water-impervious wall, characterized in that a guiding region for guiding leachate from the inner wall to the monitoring region is formed in communication therewith. 2. The impermeable wall according to claim 1, wherein the guide region is filled with a drain material such as crushed stone or gravel. 3. An underground continuous wall is constructed so as to surround a storage space for storing pollutants, and then the inside of the underground continuous wall is cut to form a double wall composed of an inner wall and an outer wall. Construction of an impermeable wall, characterized in that a monitoring region capable of pumping leachate from the inner wall and a guiding region for guiding leachate from the inner wall to the monitoring region are formed in communication in the hollow space between the heavy walls. Method.