JPH1099809A - Water impermeable structure and construction method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Although the waterproof sheet has a double structure, construction is easy, and furthermore, the storage efficiency of waste does not significantly decrease, and the waterproof sheet has excellent durability. Provide a water structure and its construction method. SOLUTION: The water-blocking structure is formed by laminating an upper water-blocking sheet 22 made of a material excellent in impact resistance and weather resistance and having a roughened lower surface at the top of the layer, and is also resistant to water. A lower water-impervious sheet 21 made of a material having excellent impact resistance and weather resistance and having rough upper and lower surfaces.
Was laminated below the upper impermeable sheet 22. In the construction method, the layers are sequentially laid while regulating the sliding of the layers constituting the water-blocking structure by the rough surfaces of the upper and lower water-blocking sheets 22 and 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-blocking structure for preventing harmful substances from flowing out at a waste disposal site and a method of constructing the same.

[0002]

2. Description of the Related Art As is well known, landfill treatment as final disposal of waste is performed by cutting a huge recess in a mountainous area or an inland area. In addition, in order to dump waste into the excavated pit, it is necessary to prevent toxic substances from escaping from the dumped waste and contaminating surrounding soil, groundwater, rivers, etc. Has a water-blocking structure in which water-blocking sheets are laid all over the recess.

[0003] As the above-mentioned waterproof sheet, those made of vulcanized rubber or thermoplastic resin are mainly used, and among those made of thermoplastic resin, those made of polyethylene having excellent impact resistance and weather resistance are used. Sheets are preferably used. In addition, a protection mat made of a nonwoven fabric or the like is usually laid below the water-impervious sheet in order to protect the water-impervious sheet from rocks or the like protruding from the bottom surface or the slope of the recess.

[0004]

Recently, related ministries and agencies have issued a notification that the water-impervious sheet should have a double structure or the like in order to more reliably impermeable the water at the waste disposal site. However, in order to cope with this, it has been found that the following problems occur when the waterproof sheet is simply made to have a double structure.

[0005] That is, when the waterproof sheet has a double structure, in particular, between the waterproof sheets on the slopes, as a drainage material, and in order to provide a gap for increasing the effect of the double structure, Since a protection mat made of a non-woven fabric is also laid, a multilayer structure having four layers is provided together with the lower protection mat. In the case of such a multilayer structure, if the upper and lower water-impervious sheets are made of tough polyethylene having excellent impact resistance and weather resistance, it is a slippery material. There is a high possibility that the layers will slip between the sheets or mats. For this reason, the upper and lower water-impervious sheets, protective mats, and the like may slide down during construction on a slope that is an inclined surface, and there is a problem that construction is not easy.

In order to prevent such slipping, the slope of the slope may be made gentle, but in this case, a new problem that the efficiency of storing waste is significantly reduced occurs. An object of the present invention is to provide a water-impervious sheet that is easy to construct despite the fact that the water-impervious sheet has a double structure, and that does not significantly reduce waste storage efficiency and that has excellent durability. And its construction method.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a water-impervious structure according to the present invention impervious to the bottom surface and the slope of a recess for waste disposal, and at least the slope of the slope is provided. An upper water-impervious sheet with a water-impervious structure laminated on the top of the layer,
The lower water-impervious sheet and the lower water-impervious sheet are formed of a material having excellent impact resistance and weather resistance. And the lower surface and the lower surface of the upper water-impervious sheet are each formed on a rough surface so as to restrict the sliding of each layer constituting the water-impervious structure along the slope.

According to this structure, since both the upper and lower water-impervious sheets are made of a material having excellent impact resistance and weather resistance such as polyethylene, the toughness of the water-impervious structure is improved, and the durability is improved. improves. The upper and lower surfaces of the lower impermeable sheet, and the lower surface of the upper impermeable sheet, respectively, are intended to regulate the sliding of the layers constituting the impermeable structure, such as the impermeable sheets and the protection mat, along the slope. Since it is formed on a rough surface, construction is easy, and the slope of the slope does not have to be gentle, so that the efficiency of storing waste does not decrease.

[0009] In order to construct the above-mentioned impermeable structure,
The construction method of the present invention is characterized in that at least each layer constituting the water-blocking structure on the slope is slid down along the slope, and the upper and lower surfaces formed on the rough surface of the lower water-blocking sheet included in the water-blocking structure. ,
In addition, the above layers are sequentially laid while being regulated by the lower surface formed on the rough surface of the upper impermeable sheet.

According to this configuration, at least the upper and lower surfaces of the lower water-impervious sheet and the lower surface of the upper water-impervious sheet included in at least the water-impervious structure of the slope are formed as rough surfaces. When sequentially laying each layer that constitutes the impermeable structure on the surface, the upper and lower impermeable sheets themselves, or other layers that are in contact with both impermeable sheets, are less likely to slip along the slope. Easy to construct. Further, since both of the water impermeable sheets are excellent in impact resistance and weather resistance, they are not damaged during construction.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing an example of the embodiment. As shown in FIG. 1 (b), the water-blocking structure of this example is installed in a huge, for example, several-hundred-meter-unit depression 1 formed by excavating a valley in a mountain area. The recess 1 includes a substantially flat bottom surface 11 and a slope 12 around the bottom surface 11.
2 is the first, second and third 3
The step slopes 12a, 12b, and 12c are each a small step 1
3 are arranged in a multi-stage structure. Further, fixing works 14 for fixing the water-blocking structure are arranged on each of the small steps 13 and the ground surface 15 around the recess 1.

Of the above, the water-blocking structure on the slope 12 is as follows:
As shown in FIG. 1 (a), the upper and lower double impermeable sheets 21, 2
2, a protection mat 23 laid under the lower water-impervious sheet 21 and made of nonwoven fabric and the like, and a protection mat 24 laid between the water-impervious sheets 21 and 22 and also made of nonwoven fabric and the like.
It is composed of Of the above, the lower impermeable sheet 21 is
As described above, the upper surface and the lower surface are both formed with rough surfaces in order to regulate the sliding of the layers constituting the water-blocking structure along the slope 12. In addition, the upper water-blocking sheet 22 has a lower surface formed with a rough surface to regulate the sliding of the layers constituting the water-blocking structure along the slope 12 in the same manner as described above.

The upper and lower surfaces of the lower water-impervious sheet 21 and the lower surface of the upper water-impervious sheet 22 are not particularly limited in the shape and degree of the rough surface.
In order to reliably control the sliding along the slope 12, the height of the projections of the unevenness forming the rough surface is about 0.5 to 4 mm, and the number of projections is ^two per cm ^2. It is preferable that this is the case. The height of the convex part is less than 0.5 mm,
Alternatively, if the number of protrusions is less than ² per 1 cm ^2, the effect of preventing slippage may be insufficient. Conversely, when the height of the convex portion exceeds 4 mm, not only is it difficult to process, but also there is a possibility that the effect of preventing slipping is not accompanied.

The shape of the irregularities is preferably irregular rather than regular in order to reliably control the sliding of the layers constituting the water-blocking structure along the slope 12. It is preferable to have a continuous wavy shape or ridge shape rather than a mountain shape. The thickness of the water shielding sheets 21 and 22 is not particularly limited. However, it is preferable that the average value of the concave and convex portions forming the rough surface, that is, the average value of the minimum thickness portion is about 0.5 to 4 mm.

The average value of the minimum part of the thickness is 0.5 mm
If it is less than the strength, the strength is insufficient, and the water shielding sheets 21 and 22 may be easily damaged. Conversely, those having an average value of the minimum thickness portion of more than 4 mm are impermeable sheets 21 and 22.
Although it depends on the material constituting the material, the rigidity is increased, which may cause inconvenience in handling such as construction. The average value of the minimum thickness is 0.8
It is preferably about 2.5 mm, more preferably about 1 to 2 mm.

The upper surface of the upper water shielding sheet 22 is preferably, but not limited to, a smooth surface. When the upper surface of the upper water-impervious sheet 22 is a smooth surface, damage to the water-impervious structure due to the downward pulling of the water-impervious structure due to, for example, sinking of the waste accumulated in the recess is reduced. Is further improved.

The water shielding sheets 21 and 22 are made of a material having excellent impact resistance and weather resistance as described above. Examples of the material having excellent impact resistance and weather resistance include, but are not limited to, high density polyethylene (HDP).
E), thermoplastic resin such as low density polyethylene (LDPE), very low density polyethylene (VLDPE), or ethylene-propylene-diene copolymer rubber (EPD)
M) and vulcanized rubber such as butyl rubber (IIR).

The impermeable sheet 21, which satisfies the above conditions,
Examples of suitable sheets for the sheet 22 include a sheet made of high-density polyethylene and having both surfaces or one surface roughened by an air bubbling method (a rough surface HDPE sheet manufactured by Polyflex), and a knurling process. It is also possible to use a sheet having an uneven surface formed by texturing or the like.

As described above, the water-impervious structure including the two water-impervious sheets 21 and 22 and the two-layer protective mats 23 and 24 is provided on each of the small steps 13 and the ground surface 15 around the recess 1, respectively. It is fixed to the slope 12 of the recess 1 by the fixing work 14 provided. The fixing work 14 is provided with the small step portion 13 and the ground surface 1.
In the groove formed in 5, the sheets and mats constituting the water-blocking structure are embedded and fixed. All the sheets and mats may be embedded and fixed in the groove at one time. In the portion of the work 14, in order to protect the upper water-impervious sheet 22 from concrete or earthmass cast in the trench, a protective mat is further required on the water-impervious sheet 22. Sheets and mats need to be fixed at once. For this reason, it is preferable to adopt, for example, the structure shown in FIG. 2 in order to more reliably fix the sheet or the mat while preventing any sheet or mat from being displaced by the weather or the like.

In the fixing step 14 shown in FIG.
Protective mat 2 laid at the bottom of the groove 14a formed in
3. Insert the lower water-impervious sheet 21 and the protection mat 24a into the groove 1
Concrete or earth mass 14b cast halfway through 4a
Buried and fixed. Next, the protection mat 24b, the upper water-impervious sheet 22, and the protection mat 25 laid on the concrete or the earth mass 14b are buried and fixed by the concrete or earth mass 14c cast thereon.

According to this configuration, the number of sheets and mats is further increased to six, but the fixed number of each time is three, and when fixing five sheets or mats at a time, Since the number of sheets is reduced as compared with the above, it is easy to reliably perform the operation without displacement. The depth of the lower concrete or earth mass 14b in the middle of the groove 14a is not particularly limited, but it is preferable that the concrete or the earth mass 14b is cast to a depth of about 1/3 of the groove 14a. When the lower concrete or earth mass 14b is cast out of the above range, the amount of the upper concrete or earth mass 14c is insufficient, and the protection mat 24b, the upper concrete or earth mass 14c is formed by the upper concrete or earth mass 14c. The fixing force of the water-impervious sheet 22 and the protection mat 25 becomes insufficient, and there is a possibility that the sheet or the mat may be displaced, turned up, or slipped off.

It is preferable that the cross-sectional area of the groove 14a is set to be approximately twice as large as that of the conventional one in order to increase the fixing force of the sheet or mat by the upper concrete or earth mass 14c. Next recess 1
For example, as shown in FIG. 3, the water-blocking structure of the substantially flat bottom surface 11 includes a protection mat 23 and a lower water-blocking sheet 21.
And the protective mat 24a are laid in this order,
1 and lay the protective mat 24 on the cover soil 31.
b, the upper impermeable sheet 22 and the protection mat 25 are laid in this order, and the covering soil 32 is further laid thereon.

In each of the above-mentioned layers, a sewage drain pipe 41 for collecting sewage mainly from wastes and leading the sewage to the outside of the disposal site is buried at predetermined intervals in the covering soil 32 on the upper impermeable sheet 22. In the base 11 below the lower impermeable sheet 21,
Groundwater drainage pipe 42 that collects groundwater and leads it out of the disposal site
Are also buried at predetermined intervals. As the drain pipes 41 and 42, pipes and the like having through holes formed at predetermined intervals are preferably used, and as shown in the figure, a layer of gravel 43 is formed around the pipe so as to easily collect sewage and groundwater. ,
44 are formed.

In the soil cover 31 between the upper and lower impermeable sheets 21 and 22, a water leak detection pipe 45 for detecting the leakage of sewage from the impermeable sheet 22 is buried at a predetermined interval. This water leak detection pipe 45 is made of a pipe or the like having through holes formed at predetermined intervals, like the drain pipes 41 and 42.
The water that has entered the water leak detection pipe 45 from the through hole is taken out of the disposal site, and the quality of the water is analyzed to detect the presence or absence of leakage of sewage or groundwater.

As the covering soil 31 in which the water leakage detection pipe 45 is buried, an impermeable soil material, for example, clay or the like is suitably used in order to prevent permeation of sewage. Similarly, an impermeable soil material such as clay is preferably used as a base material constituting the bottom surface 11 or the slope 12 of the disposal site in order to prevent infiltration of sewage and groundwater. Therefore, when creating a hole in the disposal site, a clay land may be selected or a clay layer may be formed at the time of creation.

As the lower water-impervious sheet 21 and the upper water-impervious sheet 22 laid on the bottom surface 11, the above-mentioned sheets made of a material having excellent impact resistance and weather resistance are preferably employed. However, on the bottom surface 11, the slope 1
Since it is not necessary to perform non-slip as in 2, in consideration of easiness of construction work, cost, and the like, both the lower water-impervious sheet 21 and the upper water-impervious sheet 22 have a normal surface with both surfaces formed in a smooth surface. Preferably, a sheet is employed.

On the bottom surface 11, the upper waterproof sheet 2
2, a sheet made of the above-described material having excellent impact resistance and weather resistance was used.
A sheet made of another material may be used. Examples of such a sheet made of another material include polyvinyl chloride (PVC) and ethylene-vinyl acetate copolymer (EV
A) and other sheets made of thermoplastic resin, SBS, S-
Examples include a sheet made of a thermoplastic elastomer such as EB-S or S-I-S, or a sheet made of modified asphalt to which polyethylene or the like is added.

Next, a construction method of the present invention for constructing the above-described water-blocking structure on the slope 12 of the recess 1 will be described with reference to FIG. 1 (a). In addition, the formation of the recess 1 is generally performed while digging down one step from the ground surface 15 in units of small steps 13 provided in the middle. And first
After the step is dug down, a protective mat 23 is laid on the slope 12a, and then the lower water-impervious sheet 21, the protective mat 24, and the upper water-impervious sheet 22 are laid on the protective mat 23 in this order.

The upper ends of the sheets and the mats are fixed by the above-mentioned fixing work 14 provided on the ground surface 15. The recess 1 is a huge hole as described above, and the slope 12a also has a large area, so that it is difficult to construct the water-blocking structure at one time. For this reason, normally, a sheet and a mat having a predetermined width are sequentially laid in the lateral direction of the slope 12a, respectively, and the water-impervious sheets 21 and 22 are further processed while joining each other.

In this case, the joining of sheets made of a thermoplastic resin such as polyethylene, for example, requires simple operation,
Heat welding, in which the lap portion of the two sheets is heated and pressed directly to join them directly, is preferably employed because of the advantage such as quickness of the work that the joining is completed immediately after cooling. For the heat welding, a method such as heating with an electric iron, pressurization, or hot air heating and pressure bonding with a roller is employed.

Next, after the second level of digging is completed, the impermeable sheets 21 and 22 are placed on the slope 12b in the same procedure as described above.
Then, a waterproof structure having a four-layer structure of the protection mats 23 and 24 is constructed. The upper ends of the sheets and the mats are fixed by the above-described fixing work 14 provided on the step 13 between the slopes 12a and 12b. Impermeable sheets 21 and 22
Works while joining neighboring objects together. At the same time, the upper ends of the impermeable sheets 21 and 22 are
Impermeable sheet 2 laid on the slope 12a directly above
1 and 22 are joined to the lower ends. These joints are performed in the same manner as described above.

In this manner, the steps of the number of steps (three steps in FIG. 1 (b)) constituting the recess 1 are dug down, and the impermeable structure is constructed on each of the slopes 12a. However, at this time, since the upper and lower surfaces of the lower water-impervious sheet 21 and the rough surface formed on the lower surface of the upper water-impervious sheet 22 prevent slippage, the water-impervious sheets 21 and 22 and the protection mat 2
4 is reliably prevented from sliding down along the slopes 12a. Therefore, it is easy to construct the above-described four-layer water-impervious structure on the slope 12 that is an inclined surface.

After the construction of the water-blocking structure on the slope 12 as described above is completed, the above-described water-blocking structure is formed on the formed bottom surface 11. Since the bottom surface 11 also has a large area, a sheet and a mat having a predetermined width are sequentially laid out, and the water-impervious sheets 21 and 22 are further joined together by joining adjacent ones. . In addition, the water-impervious sheets 21 and 22 on the peripheral edge of the bottom surface 11 are joined to the lower ends of the water-impervious sheets 21 and 22 laid on the lowermost slope (in FIG. 1B, the slope 12c). I do.

It should be noted that the water shielding structure and the construction method of the present invention are not limited to those described above. For example, the combination of the sheet and the mat constituting the water-blocking structure is not limited to the four-layer structure described above.
The number of layers may be three or less, or five or more. In addition, various design changes can be made without departing from the scope of the present invention.

[0035]

As described above, according to the present invention, construction is easy even though the impermeable sheet has a double structure, and the storage efficiency of waste is not significantly reduced. It has a unique effect of being able to provide a water-blocking structure with excellent performance and an efficient construction method.

[Brief description of the drawings]

FIG. 1 (a) is an enlarged cross-sectional view showing an example of an embodiment of a slope portion which is a main part of a water-blocking structure according to the present invention, and FIG. FIG. 4 is a cross-sectional view showing the entirety of the waste treatment recess to which the process is applied.

FIG. 2 is an enlarged cross-sectional view of a fixed part in an example of the water-blocking structure.

FIG. 3 is an enlarged cross-sectional view of a bottom surface portion of an example of the water shielding structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concavity 11 Bottom surface 12 Slope 21 Lower impermeable sheet 22 Upper impermeable sheet

Claims (4)

[Claims] An impermeable structure for impermeable to a bottom surface and a slope of a recess for waste treatment, wherein at least the impermeable structure of the slope is provided with an upper impermeable sheet laminated on the uppermost layer. , The lower water-impervious sheet and the lower water-impervious sheet laminated below, and the upper water-impervious sheet and the lower water-impervious sheet are made of a material having excellent impact resistance and weather resistance. An upper surface and a lower surface, and a lower surface of the upper water-impervious sheet are each formed on a rough surface so as to regulate sliding of each layer constituting the water-impervious structure along a slope. . 2. The impermeable structure according to claim 1, wherein the upper surface of the upper impermeable sheet is formed as a smooth surface. 3. The water impermeable structure according to claim 1, wherein the upper water impermeable sheet and the lower water impermeable sheet are made of high-density polyethylene. 4. A construction method for constructing a water-blocking structure according to claim 1, wherein at least each layer constituting the water-blocking structure of the slope is slid down along the slope. The above-mentioned layers are sequentially laid while being regulated by the upper and lower surfaces formed on the rough surface of the lower water-impervious sheet and the lower surface formed on the rough surface of the upper water-impervious sheet. Construction method of water structure.