JP2020175314A - Placing method of waterproof sheet - Google Patents

Abstract

To provide a preferable method for placing a waterproof sheet in a deep internal water surface disposal site.SOLUTION: The method for placing a waterproof sheet in a waste disposal site 1 includes: an excavation groove formation process for forming excavation grooves 30, 31 in an underground before construction of an underground continuous wall (a first wall part 11) and formation of an internal space 7; a side part waterproof sheet attaching process for attaching a side part waterproof sheet 4 to a reinforcing-bar cage 20 so as to cover one side of the reinforcing-bar cage 20; a reinforcing-bar cage insertion process for inserting the reinforcing-bar cage 20 with the side part waterproof sheet 4 attached thereto, into the excavation grooves 30, 31; an underground continuous wall construction process for installing a concrete in the excavation grooves 30, 31 into which the side part waterproof sheet 4 and the reinforcing-bar cage 20 are inserted and for constructing the underground continuous wall; and an internal space formation process for drill-forming the internal space 7 surrounded by the underground continuous wall. In the reinforcing-bar cage insertion process, the reinforcing-bar cage 20 is inserted into the excavation grooves 30, 31 in a manner that the side part waterproof sheet 4 attached to the reinforcing-bar cage 20 is positioned at the inner peripheral surface of the underground continuous wall after the underground continuous wall construction process.SELECTED DRAWING: Figure 6

Description

The present invention relates to a method of laying a waterproof sheet in a waste disposal site (final disposal site) for landfill disposal of waste.

Waste is classified into general waste and industrial waste, and general waste is disposed of in the form of food waste, crushed waste, incineration ash, etc. at a general waste final disposal site prepared by the local government. The final disposal sites for general waste are (1) land disposal sites, sea surface (inland water surface) disposal sites, (2) flat disposal sites, deep disposal sites, (3) no roof (open type), and covered. It is divided into (closed system). Both are legally equivalent to managed waste disposal sites.

Conventionally, various techniques for laying an impermeable sheet in a sea surface (inland water surface) disposal site have been proposed (see, for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2002-066493 JP-A-2002-126683

The impermeable sheet laying technique as disclosed in Patent Documents 1 and 2 can be used for a sea surface disposal site having a water depth of about 10 m. However, it has been difficult to use the impermeable sheet laying technique as disclosed in Patent Documents 1 and 2 when laying the waterproof sheet in the deep type / inland water surface disposal site having a water depth of about 30 to 50 m. That is, at present, a suitable method for laying a tarpaulin in a deep-type inland water disposal site has not been established.

In view of such an actual situation, it is an object of the present invention to provide a suitable method for laying a waterproof sheet in a deep type / inland water surface disposal site.

Therefore, the method of laying the tarpaulin in the first aspect of the present invention includes a tubular underground continuous wall that has an internal space for dumping waste and extends vertically in the ground, and a lower side of the underground continuous wall. This is a method of laying a tarpaulin in a waste disposal site having a bottom that closes the opening. The method of laying the waterproof sheet in the first aspect of the present invention is an excavation groove forming step of forming an excavation groove in the ground by excavating the underground in the vertical direction prior to the construction of the underground continuous wall and the formation of the internal space. And the side waterproof sheet mounting process that attaches the side waterproof sheet to the reinforcing bar cage so as to cover one side of the reinforcing bar cage, and the reinforcing bar cage inserting process that inserts the reinforcing bar cage with the side waterproof sheet into the excavation groove. By placing concrete in the excavation ditch where the side waterproof sheet and the reinforcing bar cage are inserted, the underground continuous wall construction process to construct the underground continuous wall made of reinforced concrete and the constructed underground continuous wall It includes an internal space forming step of forming the internal space by excavating the enclosed underground. In the reinforcing bar cage inserting step, the reinforcing bar cage is inserted into the excavation groove so that the side waterproof sheet attached to the reinforcing bar cage is located on the inner peripheral surface of the underground continuous wall after the underground continuous wall construction step.

The method of laying the tarpaulin in the second aspect of the present invention includes a tubular underground continuous wall that has an internal space for dumping waste and extends vertically in the ground, and a lower opening of the underground continuous wall. This is a method of laying a tarpaulin in a waste disposal site that has a bottom that closes the part. The method of laying the tarpaulin in the second aspect of the present invention is the upper end of each of a plurality of guide rails provided on the inner peripheral surface of the continuous underground wall at intervals in the circumferential direction of the continuous underground wall and extending in the vertical direction. A lowering device setting process for arranging the lowering device, a bottom waterproof sheet attaching process for attaching the outer edge of the bottom tarpaulin to the lowering device after the lowering device setting process, and a guide rail for the lowering device to which the bottom waterproof sheet is attached. It includes a bottom waterproof sheet lowering step of lowering the bottom tarpaulin to the bottom of the waste disposal site by lowering the guide rail from the upper end to the lower end while guiding.

According to the first aspect of the present invention, since the side waterproof sheet can be laid on the inner peripheral surface of the underground continuous wall at the same time as the construction of the underground continuous wall, the waterproof sheet can be easily installed in the waste disposal site. Moreover, it can be laid efficiently. This is suitable for laying a tarpaulin in a deep type / inland water disposal site.

According to the second aspect of the present invention, the bottom tarpaulin is waste by lowering the lowering device to which the bottom tarpaulin is attached while being guided by a guide rail provided on the inner peripheral surface of the continuous underground wall. Since it can be lowered to the bottom of the disposal site, a waterproof sheet can be easily and efficiently laid in the waste disposal site. This is suitable for laying a tarpaulin in a deep type / inland water disposal site.

The figure which shows the schematic structure of the waste disposal site in one Embodiment of this invention. The figure which shows the laying method of the waterproof sheet in the said embodiment. The figure which shows the laying method of the waterproof sheet in the said embodiment. The figure which shows the laying method of the waterproof sheet in the said embodiment. The figure which shows the laying method of the waterproof sheet in the said embodiment. The figure which shows the construction method of the 1st wall part (the underground continuous wall) and the laying method of the side waterproof sheet in the same embodiment. The figure which shows the method of installing the side waterproof sheet and the sheet member in the reinforcing bar cage in the same embodiment. The figure which shows the laying method of the bottom waterproof sheet in the said embodiment. The figure which shows the schematic structure of the lowering apparatus in the said embodiment. The figure which shows the installation method of the connection part waterproof sheet in the said embodiment. The figure which shows the schematic structure of the connection part waterproof sheet unit in the said embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration of a waste disposal site 1 according to an embodiment of the present invention.

The waste disposal site 1 is a closed system / deep waste disposal site for landfill disposal of waste. The waste disposal site 1 is a structure for waste disposal. In the present embodiment, the waste disposal site 1 is a water surface disposal type in which waste is dumped on the water surface WS in the waste disposal site 1, and is therefore an inland water surface disposal site.

The tubular wall body 2 of the waste disposal site 1 is constructed so as to extend downward from the ground GL2. Here, in FIG. 1, below the ground GL2, the original ground (construction ground) G1 and the embankment G2 are formed. That is, the wall 2 of the waste disposal site 1 is surrounded on the side thereof by the original ground G1 and the embankment G2.

Here, the ground GL2 shown in FIG. 1 corresponds to the upper surface of the embankment G2. The ground GL1 shown in FIG. 1 corresponds to the upper surface of the original ground G1 (the lower surface of the embankment G2). Note that FIG. 1 illustrates the groundwater level WL of the original ground G1.

The waste disposal site 1 includes a wall body 2, a roof 3, a side tarpaulin 4, a connection tarpaulin 40 (see FIGS. 10 and 11), a bottom tarpaulin 5, and a holding concrete 6. Consists of.
In this embodiment, the wall body 2 has a cylindrical shape. The wall body 2 extends vertically in the ground (in the original ground G1 and in the embankment G2). The wall body 2 surrounds the internal space 7 for landfilling waste. In other words, the wall body 2 has an internal space 7 inside which the waste is dumped. Water W can be stored in the internal space 7.

The wall body 2 is composed of a tubular first wall portion 11 and a second wall portion 12 extending in the vertical direction. The first wall portion 11 constitutes the lower portion of the wall body 2, and the second wall portion 12 constitutes the upper portion of the wall body 2. In the present embodiment, both the first wall portion 11 and the second wall portion 12 are cylindrical.

The first wall portion 11 is buried in the original ground G1. In the present embodiment, the first wall portion 11 is made of a reinforced concrete underground continuous wall (RC continuous wall). The first wall portion 11 is configured to include leading elements 17 and trailing elements 18 that are alternately arranged in the circumferential direction thereof (see FIG. 6). In this embodiment, the case where the concrete cutting method is used as the method for constructing the first wall portion 11 (continuous underground wall) will be described, but the method for constructing the first wall portion 11 is not limited to this.
The first wall portion 11 may have water shielding properties. Therefore, the first wall portion 11 can function as an impermeable wall.

The second wall portion 12 is erected directly above the first wall portion 11. The second wall portion 12 is surrounded by the embankment G2. The second wall portion 12 is made of, for example, reinforced concrete. The second wall portion 12 may have a water-shielding property.

The second wall portion 12 has an opening 14 that communicates inside and outside the second wall portion 12. The opening 14 penetrates the second wall portion 12. In the embankment G2, a passage 15 that connects the ground and the opening 14 is formed. This passage 15 can be used as a transport path for transporting waste from the ground to the opening 14. The passage 15 extends substantially horizontally.

The roof 3 is a dome roof made of reinforced concrete, and is connected to the second wall portion 12 so as to close the upper surface opening of the second wall portion 12 (wall body 2). In this embodiment, the air dome construction method (registered trademark) is used for the construction of the roof 3. In the air dome construction method (registered trademark), first, a membrane material (sheet) is installed so as to close the upper surface opening of the second wall portion 12, and the membrane material is pressurized by blowing air into the closed interior. Inflate. Next, a lath wire mesh is laid on the film material and sprayed concrete is sprayed to form a mortar dome. Next, a reinforcing bar is placed on the mortar dome, and concrete is placed and cured. In this way, the roof 3 can be constructed.

In the present embodiment, the roof 3 is a dome roof made of reinforced concrete, but the roof 3 is not limited to the dome roof made of reinforced concrete. For example, the roof 3 may be any one of a flat roof made of reinforced concrete, a T-girder flat roof made of prestressed concrete, a suspended roof made of prestressed concrete, and a tent roof.
In the present embodiment, the roof 3 has a circular shape in a plan view.

The internal space 7 surrounded by the wall body 2 is formed by excavating the inner portion of the wall body 2 in the original ground G1. This excavation is divided into primary excavation (aerial excavation) and secondary excavation (underwater excavation). The primary excavation is excavation from the upper surface (ground GL1) of the original ground G1 to about 3 to 4 m below the groundwater level WL. The primary excavation is performed, for example, by arranging a backhoe on the upper surface of the original ground G1 and directly loading it on a dump truck. In the secondary excavation, the excavation is performed to a predetermined depth by a bucket crane or a sand pump on a workbench that floats on the water surface WS in the internal space 7. By managing the water level in the internal space 7 to be the same as the groundwater level WL during this excavation, there is no inflow of surrounding groundwater into the internal space 7, and the flooring ground is disturbed. It can be prevented.

A bottom waterproof sheet 5 is provided on the excavation bottom surface (floor mounting surface) 8 formed by the secondary excavation. The bottom waterproof sheet 5 is a sheet-like member made of resin or rubber and has flexibility. The bottom waterproof sheet 5 can cover the excavation bottom surface 8. The bottom waterproof sheet 5 preferably has a property of not allowing water to permeate at all (water impermeability), but in addition to this, it may be substantially impermeable to water (that is, has a slight water permeability). You may). Here, the excavation bottom surface 8 corresponds to the "bottom portion that closes the lower opening of the continuous underground wall" of the present invention.

A side waterproof sheet 4 is provided on the inner peripheral surface of the first wall portion 11. The side waterproof sheet 4 is a sheet-like member made of resin or rubber and has flexibility. The upper end portion 4a of the side waterproof sheet 4 is located above the groundwater level WL of the surrounding ground (original ground G1) of the waste disposal site 1. The lower end 4b of the side waterproof sheet 4 reaches the excavation bottom surface 8. The side waterproof sheet 4 preferably has a property of not allowing water to permeate at all (water impermeability), but in addition to this, the side waterproof sheet 4 may be substantially impermeable to water (that is, slightly water permeable). May have).

A plurality of connection portion waterproof sheets 40 are provided on the inner peripheral surface of the first wall portion 11 at intervals in the circumferential direction (see FIG. 10). The connection portion waterproof sheet 40 is provided so as to cover the connection portion 19 (see FIG. 10) to which the ends of the leading element 17 and the trailing element 18 adjacent to each other are connected from the internal space 7 side. The connection portion waterproof sheet 40 is a sheet-like member made of resin or rubber and has flexibility. The upper end portion 40a (see FIG. 11) of the connection portion waterproof sheet 40 is located above the groundwater level WL of the surrounding ground (original ground G1) of the waste disposal site 1. The lower end of the connection portion waterproof sheet 40 reaches the excavation bottom surface 8. The connection portion waterproof sheet 40 preferably has a property of not allowing water to permeate at all (water impermeability), but in addition to this, it may be substantially impermeable to water (that is, slightly water permeable). May have).

The holding concrete 6 is connected to the outer edge portion 5a of the bottom waterproof sheet 5 and the lower end portion 4b of the side waterproof sheet 4 at a corner portion (corner portion) between the excavated bottom surface 8 and the inner peripheral surface of the first wall portion 11. It is placed so as to cover the lower end portion of the waterproof sheet 40. In the present embodiment, the holding concrete 6 is an annular shape along the inner peripheral surface of the first wall portion 11 of the wall body 2 in a top view.

In the present embodiment, during the operation of the waste disposal site 1, the water surface WS in the internal space 7 can be managed so as to be slightly lower than the groundwater level WL. A pumping pipe 9 is used to manage the water level in the internal space 7.
The pumping pipe 9 extends in the vertical direction and is arranged along the wall body 2 (first wall portion 11 and second wall portion 12). The pumping pipe 9 penetrates the roof 3 from above the roof 3 and reaches the inside space 7. The lower end 9a of the pumping pipe 9 is located in the water in the internal space 7. The lower end 9a of the pumping pipe 9 is arranged so as to be at a position about 10 m lower than the water surface WS in the internal space 7 when the waste disposal site 1 is operated. The lower end 9a of the pumping pipe 9 is located above the excavation bottom surface 8 and is separated from the excavation bottom surface 8 by, for example, 10 m or more.

Next, a method of constructing the waste disposal site 1 will be described.
In the method of constructing the waste disposal site 1, first, the side waterproof sheet 4 is laid while constructing the first wall portion 11 on the original ground G1. The method of constructing the first wall portion 11 and the method of laying the side waterproof sheet 4 will be described later with reference to FIGS. 6 and 7.

Next, the internal space 7 is formed by excavating the inner portion of the first wall portion 11 in the original ground G1 (see FIG. 2). In this excavation, the above-mentioned primary excavation (aerial excavation) and secondary excavation (underwater excavation) are performed.
Next, the bottom waterproof sheet 5 is laid on the excavation bottom surface 8. The method of laying the bottom waterproof sheet 5 will be described later with reference to FIGS. 3, 4, 8 and 9.

Next, the connection portion waterproof sheet 40 is installed. The method of installing the connection portion waterproof sheet 40 will be described later with reference to FIGS. 10 and 11.
Next, the holding concrete 6 is placed underwater (see FIG. 5).

Next, the second wall portion 12 is constructed directly above the first wall portion 11. An opening 14 is formed when the second wall portion 12 is constructed. Further, a box culvert constituting the passage 15 is installed on the upper surface (ground GL1) of the original ground G1.

Next, embankment is performed on the upper surface (ground GL1) of the original ground G1 so as to surround the circumference of the second wall portion 12. As a result, the above-mentioned box culvert is buried in the embankment G2, so that the passage 15 is formed in the embankment G2. For the embankment G2, excavated earth and sand generated when the internal space 7 is formed can be used.

Next, the roof 3 is constructed.
Next, ancillary equipment will be installed. Here, the ancillary equipment may include pumping equipment, waste input equipment, ventilation equipment, water treatment equipment, and the like. The pumping facility may include a pumping pipe 9. The waste input facility may include a crane, a belt conveyor, and the like for inputting the waste into the internal space 7.
The waste disposal site 1 is constructed as described above.

After that, the operation is started as the waste disposal site 1, and the waste is dumped on the water surface WS in the internal space 7. During this operation, as described above, the water level in the internal space 7 is managed. Further, when the dumping of waste into the internal space 7 progresses and the waste begins to exceed the groundwater level WL, the dumping is switched to aerial dumping. In this aerial dumping, for example, soil pushing and compaction by a bulldozer can be performed.

Next, a method of laying a waterproof sheet (side waterproof sheet 4, connection portion waterproof sheet 40, and bottom waterproof sheet 5) in the waste disposal site 1 will be described with reference to FIGS. 2 to 11.

2 to 5 show a method of laying a waterproof sheet (side waterproof sheet 4, connection portion waterproof sheet 40, and bottom waterproof sheet 5). FIG. 6 shows a method of constructing the first wall portion 11 and a method of laying the side waterproof sheet 4. FIG. 7 shows a method of installing the side waterproof sheet 4 and the sheet member 25 in the reinforcing bar cage 20. FIG. 8 shows a method of laying the bottom waterproof sheet 5. FIG. 9 shows a schematic configuration of the lowering device 50. FIG. 10 shows a method of installing the connection portion waterproof sheet 40. FIG. 11 shows a schematic configuration of the connection portion waterproof sheet unit 41. For details, FIG. 11A is a top view of the connection portion waterproof sheet unit 41, and FIG. 11B is an upper portion of the connection portion waterproof sheet unit 41. It is a partial front view (a view seen from the internal space 7 side) of.

Here, FIGS. 6 to 8 and 10 show a state in which the reinforcing bar cage 20 is viewed from above, and the left-right direction of the paper surface in FIGS. 6 to 8 and 10 corresponds to the circumferential direction of the first wall portion 11. To do. 6 to 8 and 10 show that the circumferential direction of the first wall portion 11 extends linearly in the left-right direction of the paper surface, but in reality, the circumferential direction of the first wall portion 11 is curved ( It extends in an arc shape). Further, FIGS. 11A and 11B are shown so as to correspond to the illustration of FIG. 10 for convenience of explanation.

In the method of laying the tarpaulin in the present embodiment, first, a mounting member 23 including an arm member 21 and a guide rail 22 is provided on the reinforcing bar cage 20 on the ground (for example, on a temporary yard near the waste disposal site 1). (See FIG. 7A: Mounting member installation process). In the present embodiment, three mounting members 23 are attached to one reinforcing bar cage 20, but the number of mounting members 23 attached to one reinforcing bar cage 20 is not limited to three, and any number of two or more is attached. Can be. In other words, the number of guide rails 22 provided on one leading element 17 may be two or more, and the number of guide rails 22 provided on one trailing element 18 may be two or more.
Here, the plurality of attachment members 23 attached to one reinforcing bar cage 20 can be arranged at intervals in the circumferential direction of the first wall portion 11.

The arm member 21 extends so as to project outward from one side surface 20a of the reinforcing bar cage 20. A reinforcing bar cage 20 is connected to the base end portion of the arm member 21, and a guide rail 22 is connected to the tip end portion. Therefore, the guide rail 22 is provided on one side of the reinforcing bar cage 20 via the arm member 21. Here, the length of the arm member 21 can be set in consideration of the cover thickness of the reinforcing bar.

The guide rail 22 has a C-shaped cross section and extends in the vertical direction. The guide rail 22 may be formed of, for example, a steel pipe having a slit 22a in the vertical direction. The side of the guide rail 22 on which the slit 22a is formed may face the internal space 7. The guide rail 22 has a length (height) similar to the distance from the ground GL1 to the excavation bottom surface 8.

Next, by attaching the side waterproof sheet 4 to the guide rail 22 on the ground (for example, on a temporary yard near the waste disposal site 1), the side waterproof sheet 4 is attached to the guide rail 22 and the arm member 21 (mounting member). It is attached to the reinforcing bar cage 20 via 23) (see FIG. 7 (a): side waterproof sheet attachment step). In this step, the side waterproof sheet 4 is attached to the reinforcing bar cage 20 via the guide rail 22 and the arm member 21 (attaching member 23) so as to cover one side (most of one side surface 20a) of the reinforcing bar cage 20. Note that FIG. 7A shows an example in which the side waterproof sheet 4 is attached to the guide rail 22 in a taut state, but instead of this, the side waterproof sheet 4 is in a loosened state (relaxed state). It goes without saying that it may be attached to the guide rail 22 with).
The side waterproof sheet 4 preferably has a length (height) similar to the distance from the ground GL1 to the excavation bottom surface 8.

In this "side waterproof sheet attaching step", the sheet member 25 covers the outer surface (the surface on the side opposite to the side facing the reinforcing bar cage 20) 4c of the side waterproof sheet 4 and the slit 22a of the guide rail 22. Is included in the guide rail 22 (see FIG. 7 (c)). The sheet member 25 is, for example, a civil engineering sheet. The seat member 25 has a function of protecting the outer surface 4c of the side waterproof sheet 4 and a function of preventing foreign matter and the like from entering the guide rail 22.
The sheet member 25 preferably has a length (height) comparable to the distance from the ground GL1 to the excavation bottom surface 8.

Before and after the above-mentioned "mounting member installation process" and "side tarpaulin installation process", or in parallel with "mounting member installation process" and "side tarpaulin installation process", underground (original ground G1 By excavating the middle) in the vertical direction using a tarpaulin, a plurality of excavation grooves 30 for constructing the preceding element 17 are formed in the original ground G1 (see FIG. 6A: excavation groove forming step for the preceding element). ). It should be noted that this "excavation groove forming step for the preceding element" constitutes the "excavation groove forming process" of the present invention.

Next, the reinforcing bar cage 20 to which the side tarpaulin sheet 4 and the sheet member 25 are attached is inserted (built) into each excavation groove 30 (see FIG. 6A: step of inserting the reinforcing bar cage for the leading element). It should be noted that this "reinforcing bar cage inserting step for the preceding element" constitutes the "reinforcing bar cage inserting step" of the present invention.

Next, the leading element 17 made of reinforced concrete is constructed by placing concrete in the excavation groove 30 into which the side waterproof sheet 4, the sheet member 25, and the reinforcing bar cage 20 are inserted (see FIG. 6 (a):). Preceding element construction process). It should be noted that this "preceding element construction step" constitutes the "underground continuous wall construction step" of the present invention.

Next, between the constructed leading elements 17, excavation in the original ground G1 in the vertical direction using a stabilizing liquid forms an excavation groove 31 for constructing the trailing element 18 in the original ground G1 (FIG. 6 (c): Drilling ditch forming process for trailing element). It should be noted that this "excavation groove forming step for a trailing element" constitutes the "excavation groove forming process" of the present invention.
Here, in the present embodiment, since the above-mentioned concrete cutting method is adopted, concrete cutting of the end portion of the preceding element 17 is carried out in the “excavation groove forming step for the trailing element”.

Next, the reinforcing bar cage 20 to which the side waterproof sheet 4 and the sheet member 25 are attached is inserted (built) into each excavation groove 31 (see FIG. 6 (d): reinforcing bar cage inserting step for trailing element). It should be noted that this "reinforcing bar cage inserting step for trailing element" constitutes the "reinforcing bar cage inserting step" of the present invention.

Next, the trailing element 18 made of reinforced concrete is constructed by placing concrete in the excavation groove 31 into which the side waterproof sheet 4, the sheet member 25, and the reinforcing bar cage 20 are inserted (see FIG. 6 (d)). : Subsequent element construction process). It should be noted that this "following element construction step" constitutes the "underground continuous wall construction step" of the present invention.

Here, in the "following element construction step", the ends of the leading element 17 and the trailing element 18 adjacent to each other are connected to each other via the connecting portion 19. Here, the connecting portion 19 is a connecting portion between the ends of the leading element 17 and the trailing element 18 that are adjacent to each other.

In this way, the first wall portion 11 including the plurality of leading elements 17 and trailing elements 18 is constructed. Further, a side waterproof sheet 4 and a sheet member 25 are laid on the inner peripheral surface of the first wall portion 11. Further, a plurality of guide rails 22 are provided on the inner peripheral surface of the first wall portion 11 at intervals in the circumferential direction of the first wall portion 11.

In the above-mentioned "reinforcing bar cage inserting step for leading element" and "rebar cage inserting step for trailing element", the side waterproof sheet 4 and the sheet member 25 attached to the reinforcing bar cage 20 are in the "leading element construction step" and. After the "following element construction step", the reinforcing bar cage 20 is inserted into the excavation grooves 30 and 31 so as to be located on the inner peripheral surface of the first wall portion 11.

Next, the internal space 7 is formed by excavating the ground (in the original ground G1) surrounded by the constructed first wall portion 11 (see FIG. 2 and FIG. 8 (a): internal space forming step). .. In this process, as described above, primary excavation (aerial excavation) and secondary excavation (underwater excavation) are performed. Then, the sheet member 25 and the attached slime are peeled off by passing a cutter or the like through the slit 22a of the guide rail 22.

Next, the lowering device 50 is arranged at the upper end of each of the plurality of guide rails 22 located on the inner peripheral surface of the first wall portion 11 (lowering device setting step: see FIG. 8A).

As shown in FIG. 9, the lowering device 50 has a main body 51 having a T-shaped cross section and extending in the vertical direction. The main body 51 is made of, for example, a CT shaped steel extending in the vertical direction, its flange 51a is arranged in the guide rail 22, and most of the web 51b is exposed by protruding from the slit 22a of the guide rail 22 into the internal space 7. doing. The lower end of the web 51b is cut diagonally.

Through holes 52 and 53 are formed through the exposed portion of the web 51b. The through hole 52 is for attaching the hanging rope 54. The through hole 53 is for connecting the ear portion 61 fixed to the outer edge portion 5a of the bottom waterproof sheet 5 to the main body portion 51 with a string 62 (see FIG. 8C).

Here, as shown in FIG. 8C, a plurality of ear portions 61 are fixed to the outer edge portion 5a of the bottom waterproof sheet 5 at intervals in the circumferential direction. In the present embodiment, an adhesive is used to fix the ear portion 61 to the outer edge portion 5a of the bottom waterproof sheet 5, but it goes without saying that the fixing may be performed by another method. The selvage 61 has a hole 63, preferably made of canvas. The hole 63 is for connecting the ear portion 61 to the main body portion 51 with a string 62.

The "lowering device setting step" includes attaching the suspension rope 54 to the main body 51 of the lowering device 50. The main body 51 of the lowering device 50 can be suspended and supported by the hanging rope 54. It is preferable that the hanging rope 54 is restrained by a restraining means (not shown) to prevent the main body 51 of the lowering device 50 from being unintentionally lowered.

The "lowering device setting step" can be performed above the water surface WS. Further, the "lowering device setting step" can be carried out in the vicinity of the upper surface opening of the first wall portion 11. Further, in the present embodiment, the side waterproof sheet 4 is provided on the inner peripheral surface of the first wall portion 11 prior to the “lowering device setting step”.

Next, the bottom waterproof sheet 5 is connected to the hole 63 of the ear portion 61 fixed to the outer edge portion 5a of the bottom waterproof sheet 5 and the through hole 53 of the main body 51 of the lowering device 50 through a string 62. The outer edge portion 5a is attached to the main body portion 51 of the lowering device 50 (bottom waterproof sheet attachment step: see FIG. 8 (c)).

Next, the restraint of the hanging rope 54 by the above-mentioned restraining means is released, and the main body 51 of the lowering device 50 to which the bottom waterproof sheet 5 is attached is guided by the guide rail 22 from the upper end to the lower end of the guide rail 22. By lowering, the bottom waterproof sheet 5 is lowered to the bottom surface 8 of the excavation (bottom waterproof sheet lowering step: see FIGS. 3 and 4). Here, FIG. 3 shows a state in the middle of the “bottom waterproof sheet lowering step”, and FIG. 4 shows a state in which the “bottom waterproof sheet lowering step” is completed.

Regarding the lowering of the main body 51 and the bottom waterproof sheet 5 of the lowering device 50, the lowering can be performed by their own weight. If the descent is stagnant due to friction between the main body 51 of the lowering device 50 and the guide rail 22, the main body 51 of the lowering device 50 can be pushed downward from the ground side by an appropriate pushing means. It can be dealt with.

In the "bottom waterproof sheet lowering step", the length (hanging length) of the hanging rope 54 of the main body 51 of the lowering device 50 provided on each of the plurality of guide rails 22 is appropriately adjusted by using the above-mentioned restraining means. By doing so, it is preferable that the bottom waterproof sheet 5 is submerged substantially evenly in the circumferential direction.

Next, the connection portion waterproof sheet 40 (connection portion waterproof sheet unit 41) is installed so as to cover the connection portion 19 connecting the ends of the leading element 17 and the trailing element 18 from the internal space 7 side (connection portion waterproofing). Sheet installation process: see FIGS. 10 (a) and 10 (b)). Here, FIG. 10A shows a state before installing the connection portion waterproof sheet unit 41. FIG. 10A shows a state after the connection portion waterproof sheet unit 41 is installed.

As shown in FIGS. 11A and 11B, the connection portion waterproof sheet unit 41 includes a connection portion waterproof sheet 40, two T joints 42, and two flat bars 43.
The T-joint 42 has a T-shaped cross section and extends in the vertical direction, and is made of, for example, CT shaped steel. The flange 42a of the T-joint 42 can be inserted into the guide rail 22 from above, and most of the web 42b of the T-joint 42 can protrude from the slit 22a of the guide rail 22 toward the interior space 7. Here, the guide rail 22 functions as a so-called P joint, and may form a joint portion together with the T joint 42. The connection portion waterproof sheet unit 41 can be connected to the first wall portion 11 via the joint portion.

The two T-joints 42 are arranged in parallel with each web 42b at a distance C1 (see FIG. 11A). Here, the interval C1 refers to the slit 22a of the guide rail 22 closest to the connecting portion 19 among the leading elements 17 and the trailing element 18 with respect to the leading element 17 and the trailing element 18 adjacent to each other with the connecting portion 19 interposed therebetween. It is set to be substantially the same as the distance C2 (see FIG. 10A) between the guide rail 22 closest to the connecting portion 19 and the slit 22a.

A flat bar 43 is attached to the tip end side (the side opposite to the flange 42a) of each of the webs 42b of the two T joints 42. The flat bar 43 extends in the vertical direction. A connection portion waterproof sheet 40 is stretched so as to straddle these flat bars 43.

In this "connection portion waterproof sheet installation process", the connection portion waterproof sheet unit 41 including the connection portion waterproof sheet 40 is guided by the guide rail 22 and lowered until the lower end portion of the connection portion waterproof sheet 40 reaches the excavation bottom surface 8. Let me.

Further, in the "connection portion waterproof sheet installation step", after the lowering of the connection portion waterproof sheet unit 41 is completed, a filler such as mortar is filled in the guide rail 22 into which the flange 42a of the T joint 42 is inserted. .. As a result, one side edge of the connection portion waterproof sheet 40 is fixed to and connected to the leading element 17 of the first wall portion 11 via the flat bar 43, the T joint 42, the filler, and the guide rail 22. The other side edge of the part waterproof sheet 40 may be fixed to the trailing element 18 of the first wall portion 11 via the flat bar 43, the T joint 42, the filler, and the guide rail 22.

Next, the pressing concrete 6 is placed so as to cover the outer edge portion 5a of the bottom waterproof sheet 5, the lower end portion 4b of the side waterproof sheet 4, and the lower end portion of the connecting portion waterproof sheet 40 (pressing concrete placing step: FIG. 5).

As described above, the waterproof sheet (side waterproof sheet 4, connection portion waterproof sheet 40, and bottom waterproof sheet 5) is laid in the waste disposal site 1. After this laying, the internal space 7 has a side waterproof sheet 4, a guide rail 22, a connection portion waterproof sheet unit 41 (connection portion waterproof sheet 40), a bottom waterproof sheet 5, and a holding concrete 6 on the sides and below. Surrounded by.

According to the present embodiment, the method of laying the waterproof sheet includes a tubular underground continuous wall (first wall portion 11) having an internal space 7 for dumping waste and extending vertically in the ground. A tarpaulin (side tarpaulin 4, connection tarpaulin 40, and connection tarpaulin 40) is contained in a waste disposal site 1 having a bottom (excavation bottom surface 8) that closes the lower opening of the underground continuous wall (first wall portion 11). This is a method of laying a bottom waterproof sheet 5). The method of laying the waterproof sheet is to form excavation grooves 30 and 31 in the ground by excavating the ground in the vertical direction prior to the construction of the underground continuous wall (first wall portion 11) and the formation of the internal space 7. "Excavation groove forming process" (see FIGS. 6A and 6) and "Side waterproof sheet mounting process" for attaching the side waterproof sheet 4 to the reinforcing bar cage 20 so as to cover one side of the reinforcing bar cage 20 (see FIG. FIG. 7 (a)) and the “reinforcing bar cage insertion step” (see FIGS. 6 (a) and (d)) in which the reinforcing bar cage 20 to which the side waterproof sheet 4 is attached is inserted into the excavation grooves 30 and 31. , By placing concrete in the excavation grooves 30 and 31 into which the side waterproof sheet 4 and the reinforcing bar cage 20 are inserted, a continuous underground wall (first wall portion 11) made of reinforced concrete is constructed. "Wall construction process" (see FIGS. 6 (a) and 6 (d)) and "excavating the ground surrounded by the constructed continuous underground wall (first wall portion 11) to form the internal space 7" Includes "internal space forming step" (see FIG. 2). In the "rebar cage insertion process" (see FIGS. 6 (a) and (d)), the side tarpaulin 4 attached to the rebar cage 20 is the "underground continuous wall construction process" (see FIGS. 6 (a) and (d)). ), Then the reinforcing bar cage 20 is inserted into the excavation grooves 30 and 31 so as to be located on the inner peripheral surface of the underground continuous wall (first wall portion 11). Therefore, the side waterproof sheet 4 can be laid on the inner peripheral surface of the underground continuous wall (first wall portion 11) at the same time as the construction of the underground continuous wall (first wall portion 11), so that the waste disposal site can be used. The side waterproof sheet 4 can be easily and efficiently laid in 1.

Further, according to the present embodiment, the underground continuous wall (first wall portion 11) includes leading elements 17 and trailing elements 18 that are alternately arranged in the circumferential direction thereof. The method of laying the waterproof sheet is to install the connection portion waterproof sheet 40 so as to cover the connection portion 19 in which the ends of the leading element 17 and the trailing element 18 adjacent to each other are connected from the internal space 7 side. "Sheet installation process" (see FIG. 10 (a)) is included. As a result, the connection portion waterproof sheet 40 can cover between the side waterproof sheet 4 laid on the leading element 17 and the side waterproof sheet 4 laid on the trailing element 18, so that the first wall. A waterproof sheet can be laid on the inner peripheral surface of the portion 11 over the entire circumference.

Further, according to the present embodiment, in the "side waterproof sheet attaching step" (see FIG. 7A), the side waterproof sheet 4 is attached to the guide rail 22 provided on one side of the reinforcing bar cage 20 and extending in the vertical direction. By attaching, the side waterproof sheet 4 is attached to the reinforcing bar cage 20 via the guide rail 22. The method of laying the waterproof sheet is the "lowering device setting process" (FIG. 8 (a)) in which the lowering device 50 is arranged at the upper end of the guide rail 22 after the "underground continuous wall construction process" (see FIG. 6 (d)). (See) and the "bottom tarpaulin mounting process" (see FIG. 8 (c)) in which the outer edge 5a of the bottom tarpaulin 5 is attached to the lowering device 50 after the "lowering device setting step" (see FIG. 8 (a)). After the "internal space forming step" (see FIG. 2) and after the "bottom waterproof sheet mounting step" (see FIG. 8 (c)), the lowering device 50 is guided by the guide rail 22 of the guide rail 22. It includes a "bottom tarpaulin lowering step" (see FIGS. 3 and 4) in which the bottom tarpaulin 5 is lowered from the upper end to the lower end to the bottom (excavation bottom surface 8) of the waste disposal site 1. Therefore, by lowering the lowering device 50 to which the bottom waterproof sheet 5 is attached while being guided by the guide rail 22, the bottom waterproof sheet 5 can be lowered to the excavation bottom surface 8, so that the bottom portion can be lowered in the waste disposal site 1. The waterproof sheet 5 can be laid easily and efficiently.

Further, according to the present embodiment, the "connection portion waterproof sheet installation step" (see FIG. 10A) is carried out after the "bottom waterproof sheet lowering step" (see FIGS. 3 and 4). In the "connection part waterproof sheet installation process" (see FIG. 10 (a)), the connection part waterproof sheet 40 is guided by the guide rail until the lower end of the connection part waterproof sheet 40 reaches the bottom of the waste disposal site (excavation bottom surface 8). It includes lowering while guiding by 22. As a result, the guide rail 22 used for laying the bottom waterproof sheet 5 can also be used for installing the connection portion waterproof sheet 40.

Further, according to the present embodiment, the method of laying the waterproof sheet is after the "bottom waterproof sheet lowering step" (see FIGS. 3 and 4) and the "connection portion waterproof sheet installation step" (see FIG. 10 (a)). ), Then the pressing concrete 6 is placed so as to cover the outer edge portion 5a of the bottom waterproof sheet 5, the lower end portion 4b of the side waterproof sheet 4, and the lower end portion of the connecting portion waterproof sheet 40. (See FIG. 5) is included. As a result, the bottom waterproof sheet 5, the side waterproof sheet 4, and the connection portion waterproof sheet 40 can be made continuous (integrated).

Further, according to the present embodiment, in the "side waterproof sheet attaching step" (see FIG. 7A), the surface (outer surface 4c) of the side waterproof sheet 4 on the side opposite to the reinforcing bar cage 20 is formed. It includes attaching the sheet member 25 for protection to the reinforcing bar cage 20 (see FIG. 7 (c)). As a result, it is possible to prevent the side waterproof sheet 4 from being damaged when the first wall portion 11 is constructed and when the internal space 7 is formed.

Further, according to the present embodiment, the method of laying the waterproof sheet is a tubular underground continuous wall (first wall portion 11) having an internal space 7 in which waste is dumped and extending vertically in the ground. This is a method of laying a waterproof sheet in a waste disposal site 1 having a bottom portion (excavation bottom surface 8) that closes a lower opening of an underground continuous wall (first wall portion 11). A plurality of methods for laying the waterproof sheet are provided on the inner peripheral surface of the continuous underground wall (first wall portion 11) at intervals in the circumferential direction of the continuous underground wall (first wall portion 11) and extend in the vertical direction. After the "lowering device setting process" (see FIG. 8 (a)) and the "lowering device setting process" (see FIG. 8 (a)) in which the lowering device 50 is arranged at the upper end of each of the guide rails 22 of the above, the bottom is waterproofed. A guide rail while guiding the lowering device 50 to which the bottom waterproof sheet 5 is attached by the guide rail 22 and the "bottom waterproof sheet attaching process" (see FIG. 8 (c)) in which the outer edge portion 5a of the sheet 5 is attached to the lowering device 50. The "bottom tarpaulin lowering step" (see FIGS. 3 and 4) of lowering the bottom tarpaulin 5 from the upper end to the lower end of 22 to the bottom (excavation bottom surface 8) of the waste disposal site 1. Including. Therefore, by lowering the lowering device 50 to which the bottom waterproof sheet 5 is attached while being guided by the guide rail 22, the bottom waterproof sheet 5 can be lowered to the excavation bottom surface 8, so that the bottom portion can be lowered in the waste disposal site 1. The waterproof sheet 5 can be laid easily and efficiently.

Further, according to the present embodiment, the side waterproof sheet 4 is laid on the inner peripheral surface of the underground continuous wall (first wall portion 11) prior to the “lowering device setting step” (see FIG. 8 (a)). There is. The method of laying the waterproof sheet is as follows: after the "bottom waterproof sheet lowering step" (see FIGS. 3 and 4), the bottom waterproof sheet 5 is pressed so as to cover the outer edge 5a of the bottom waterproof sheet 5 and the lower end 4b of the side waterproof sheet 4. Includes a "tarpaulin placing process" (see FIG. 5) in which 6 is placed. As a result, the bottom waterproof sheet 5 and the side waterproof sheet 4 can be made continuous (integrated).

In the present embodiment, the case where the concrete cutting method is used as the method for constructing the first wall portion 11 (continuous underground wall) has been described, but the method for constructing the first wall portion 11 is not limited to this, for example, the joined steel plate method. May be used. Generally, in the joint steel plate construction method, regarding the construction of the preceding element 17, the joint steel plates are provided at both ends of the reinforcing bar cage 20, and when concrete is placed in the excavation groove 30, the joint steel plate and the wall surface of the excavation groove 30 are formed. Prior to placing the concrete, a civil engineering sheet is installed to prevent the concrete from leaking from the gap between the concrete (the concrete wraps around the planned construction area of the trailing element 18). This civil engineering sheet can be utilized as the above-mentioned sheet member 25.

In the present embodiment, the bottom waterproof sheet 5 and the connection portion waterproof sheet 40 are installed prior to constructing the second wall portion 12 directly above the first wall portion 11, but instead of this, the first wall portion The bottom waterproof sheet 5 and the connection portion waterproof sheet 40 may be installed after the second wall portion 12 is constructed directly above the 11. In this case, the guide rail 22 can be extended to the upper end of the second wall portion 12.

In the present embodiment, the excavation bottom surface 8 has a property of not allowing water to permeate at all (water impermeability), or has a degree of substantially impermeability of water (that is, a degree of having a slight water permeability). In that case, the bottom waterproof sheet 5 may be omitted. In this case, the above-mentioned "lowering device setting step", "bottom waterproof sheet attaching step", and "bottom waterproof sheet lowering step" are omitted. Further, in this case, in the "pressing concrete placing step", even if the pressing concrete 6 is placed so as to cover the lower end portion 4b of the side waterproof sheet 4 and the lower end portion of the connecting portion waterproof sheet 40. Good. Alternatively, the "pressing concrete placing process" may be omitted.

In the present embodiment, if the water impermeability of the first wall portion 11 is sufficiently ensured, the side waterproof sheet 4 and the connecting portion waterproof sheet 40 may be omitted. In this case, the above-mentioned "side waterproof sheet installation step" and "connection portion waterproof sheet installation step" are omitted. Further, in this case, in the "pressing concrete placing step", the pressing concrete 6 may be placed so as to cover the outer edge portion 5a of the bottom waterproof sheet 5 described above. Alternatively, the "pressing concrete placing process" may be omitted. Further, when the side waterproof sheet 4 and the connection waterproof sheet 40 are omitted, the connection portion waterproof sheet unit 41 does not need to be installed. Therefore, it is attached to one reinforcing bar cage 20 in the above-mentioned "mounting member installation process". The number of mounting members 23 to be mounted can be any one or more. In other words, the number of guide rails 22 provided on one leading element 17 may be one or more, and the number of guide rails 22 provided on one trailing element 18 may be one or more.

In the present embodiment, a passage 15 and an opening 14 are provided for transporting the waste from the ground to the inside space 7 of the waste disposal site 1, but in addition to or instead of this, the passage 15 and the opening 14 are provided. A plurality of through holes for dumping waste may be formed in the roof 3. That is, the method of transporting the waste from the ground to the inside space 7 of the waste disposal site 1 is not limited to the above-mentioned method, and is arbitrary.

In the present embodiment, the cross-sectional shapes of the tubular wall body 2, the first wall portion 11, and the second wall portion 12 are circular, but these cross-sectional shapes are not limited to circular shapes, and are, for example, elliptical or elliptical. , It may be a polygonal shape such as a rectangular shape. The shapes of the side waterproof sheet 4, the connection portion waterproof sheet 40, and the bottom waterproof sheet 5 are appropriately set so as to correspond to the cross-sectional shapes of the tubular wall body 2, the first wall portion 11, and the second wall portion 12. obtain. Further, the shape of the roof 3 in a plan view also corresponds to the cross-sectional shape of the tubular wall body 2, the first wall portion 11 and the second wall portion 12, and is, for example, an elliptical shape or a rectangular shape. It may be in shape.

The illustrated embodiments merely illustrate the present invention, and the present invention makes various improvements and modifications made by those skilled in the art within the scope of the claims, in addition to those directly shown by the described embodiments. It goes without saying that it is an inclusion.

1 ... Waste disposal site, 2 ... Wall body, 3 ... Roof, 4 ... Side tarpaulin, 4a ... Upper end, 4b ... Lower end, 4c ... Outer surface, 5 ... Bottom tarpaulin, 5a ... Outer edge, 6 ... Tarpaulin, 7 ... Internal space, 8 ... Excavation bottom, 9 ... Pumping pipe, 9a ... Lower end, 11 ... 1st wall, 12 ... 2nd wall, 14 ... Opening, 15 ... Passage, 17 ... Leading element, 18 ... Trailing element, 19 ... Connection part, 20 ... Reinforcing bar cage, 20a ... One side, 21 ... Arm member, 22 ... Guide rail, 22a ... Slit, 23 ... Mounting member, 25 ... Seat member, 30, 31 ... Excavation Groove, 40 ... Connection part tarpaulin, 40a ... Upper end, 41 ... Connection part tarpaulin unit, 42 ... T joint, 42a ... Flange, 42b ... Web, 43 ... Flat bar, 50 ... Lowering device, 51 ... Main body, 51a ... Flange, 51b ... Web, 52, 53 ... Through hole, 54 ... Suspended rope, 61 ... Ear, 62 ... String, 63 ... Hole, C1, C2 ... Spacing, G1 ... Groundwater, G2 ... Tarpaulin, GL1, GL2 ... Ground, W ... Water, WL ... Groundwater level, WS ... Water surface

Claims (8)

Waterproof in a waste disposal site that has a tubular underground continuous wall that has an internal space for dumping waste and extends vertically in the ground, and a bottom that closes the lower opening of the underground continuous wall. It ’s a method of laying a sheet,
An excavation ditch forming step of forming an excavation ditch in the ground by excavating the underground in the vertical direction prior to the construction of the underground continuous wall and the formation of the internal space.
The side waterproof sheet attachment process of attaching the side tarpaulin to the reinforcing bar cage so as to cover one side of the reinforcing bar cage,
A rebar cage insertion step of inserting the rebar cage to which the side waterproof sheet is attached into the excavation groove, and
An underground continuous wall construction step of constructing the underground continuous wall made of reinforced concrete by placing concrete in the excavation ditch into which the side waterproof sheet and the reinforcing bar cage are inserted.
An internal space forming step of forming the internal space by excavating the underground surrounded by the constructed underground continuous wall,
Including
In the reinforcing bar cage inserting step, the reinforcing bar cage is formed in the excavation groove so that the side waterproof sheet attached to the reinforcing bar cage is located on the inner peripheral surface of the underground continuous wall after the underground continuous wall construction step. How to lay a tarpaulin to insert inside. The underground continuous wall is composed of leading elements and trailing elements that are alternately arranged in the circumferential direction.
The method of laying the waterproof sheet is a step of installing the connection portion waterproof sheet so as to cover the connection portion in which the ends of the preceding element and the trailing element adjacent to each other are connected from the internal space side. The method for laying a waterproof sheet according to claim 1, further comprising. In the side waterproof sheet attaching step, by attaching the side waterproof sheet to a guide rail provided on one side of the reinforcing bar cage and extending in the vertical direction, the side waterproof sheet is attached to the reinforcing bar via the guide rail. Attached to the basket,
The method of laying the waterproof sheet is
After the underground continuous wall construction step, a lowering device setting step of arranging the lowering device at the upper end of the guide rail, and a lowering device setting step.
After the lowering device setting step, the bottom waterproof sheet attaching step of attaching the outer edge of the bottom waterproof sheet to the lowering device,
After the internal space forming step and after the bottom waterproof sheet attaching step, the bottom waterproof sheet is lowered by lowering the lowering device from the upper end to the lower end of the guide rail while guiding the lowering device by the guide rail. The bottom waterproof sheet lowering process of lowering to the bottom of the waste disposal site,
The method for laying a waterproof sheet according to claim 1 or 2, further comprising. The connection portion waterproof sheet installation step is carried out after the bottom waterproof sheet lowering step.
The step of installing the connection portion waterproof sheet includes lowering the connection portion waterproof sheet while guiding it by the guide rail until the lower end portion of the connection portion waterproof sheet reaches the bottom portion of the waste disposal site. The method for laying a waterproof sheet according to claim 3, wherein claim 3 is subordinate to claim 2. After the bottom waterproof sheet lowering step and after the connection portion waterproof sheet installation step, the outer edge portion of the bottom waterproof sheet, the lower end portion of the side waterproof sheet, and the lower end portion of the connection portion waterproof sheet are covered. The method for laying a tarpaulin according to claim 3 or 4, wherein the step of placing the tarpaulin is further included, and the tarpaulin is placed according to claim 3 or 2. Claims 1 to claim that the side waterproof sheet attaching step includes attaching a sheet member for protecting the surface of the side waterproof sheet on the side opposite to the reinforcing bar cage to the reinforcing bar cage. Item 5. The method for laying a waterproof sheet according to any one of items 5. Waterproof in a waste disposal site that has a tubular underground continuous wall that has an internal space for dumping waste and extends vertically in the ground, and a bottom that closes the lower opening of the underground continuous wall. It ’s a method of laying a sheet,
A lowering device setting step in which a lowering device is arranged at the upper end of each of a plurality of guide rails provided on the inner peripheral surface of the underground continuous wall at intervals in the circumferential direction of the underground continuous wall and extending in the vertical direction. ,
After the lowering device setting step, the bottom waterproof sheet attaching step of attaching the outer edge of the bottom waterproof sheet to the lowering device,
The bottom portion that lowers the bottom waterproof sheet to the bottom of the waste disposal site by lowering the lowering device to which the bottom waterproof sheet is attached from the upper end to the lower end of the guide rail while guiding the lowering device with the guide rail. The tarpaulin lowering process and
How to lay a tarpaulin, including. Prior to the lowering device setting step, a side waterproof sheet is laid on the inner peripheral surface of the underground continuous wall.
The method of laying the waterproof sheet is a step of placing the holding concrete so as to cover the outer edge of the bottom waterproof sheet and the lower end of the side waterproof sheet after the bottom waterproof sheet lowering step. The method for laying a waterproof sheet according to claim 7, further comprising.