Installation method

Abstract

This invention provides a method for laying waterproof sheets that reduces the work required to connect waterproof sheets to each other on an inclined surface. [Solution] The inner surface 7 of the bowl-shaped waste disposal site 1 is provided with an inclined section 15 and a bottom section 11. The method for laying a waterproof sheet 22 on the inner surface 7 of the waste disposal site 1 comprises a sheet connection step in which a plurality of waterproof sheets 21 are connected to each other by work performed at the bottom section 11, and a traction and movement step in which the waterproof sheet 22, which has been expanded by the sheet connection step, is towed and moved and laid on the inclined section 15.

Description

[Technical Field]

[0001] This invention relates to a method for laying a waterproof sheet on the inner surface of a bowl-shaped waste disposal site. [Background technology]

[0002] Conventionally, a method for laying waterproof sheets, as described in Patent Document 1 below, is known as a technology in this field. In this method, the edges of the waterproof sheet, which has been transported to the site and cut to a predetermined length, are grasped using a sheet tensioning vise, for example by human power, and the waterproof sheet is stretched and laid on a predetermined site, such as the inner surface of a waste disposal site. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-300228 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] When the above laying method is applied to lay a waterproof sheet on the sloping inner surface of a bowl-shaped waste disposal site, the waterproof sheet is repeatedly laid on the sloping surface, resulting in multiple waterproof sheets being arranged in a two-dimensional manner. Subsequently, in order to ensure waterproofing of the waste disposal site, adjacent waterproof sheets are connected to each other by welding or other means. However, this connection work must be performed on the sloping surface of the sloping area, which often results in unstable footing for workers and poor work efficiency. Therefore, the present invention aims to provide a method for laying waterproof sheets that can reduce the work of connecting waterproof sheets to each other on a sloping surface. [Means for solving the problem]

[0005] The gist of this invention is found in the following [1] to [9].

[0006] [1] A method for laying a waterproof sheet on the inner surface of a bowl-shaped waste disposal site, wherein the inner surface comprises an inclined section and a flat section located below the inclined section with a smaller slope than the inclined section, and the method comprises a sheet connecting step of connecting a plurality of the waterproof sheets to each other by work performed on the flat section, and a towing and moving step of towing and moving the waterproof sheet that has been enlarged by the sheet connecting step and laying it on the inclined section.

[0007] [2] The installation method according to [1], wherein the flat portion is the bottom or a stepped portion of the inner surface of the waste disposal site.

[0008] [3] The laying method according to [1] or [2], wherein the towing step is performed using a towing device comprising a plurality of cables, a plurality of gripping devices attached to each of the cables for gripping the ends of the waterproof sheet, and a power device which is a power source for pulling the plurality of cables.

[0009] [4] The installation method according to [3], wherein the traction device comprises a suspension member interposed in the connection between the power device and the plurality of cables and extending in a direction intersecting the traction direction, and the plurality of cables are connected to the suspension member at intervals in the direction of extension of the suspension member.

[0010] [5] The installation method according to [3] or [4], wherein the gripping device comprises a pair of clamping members having clamping surfaces that are treated to prevent slipping against the waterproof sheet, and a magnet that generates a magnetic force in a direction that pulls the clamping surfaces together.

[0011] [6] The laying method according to any one of [1] to [5], wherein in the towing and moving step, a stretching process is performed in which the waterproof sheet being towed is pulled in a direction intersecting the towing direction.

[0012] [7] The laying method according to any one of [1] to [6], further comprising a mat laying step of laying a protective mat, which is to be installed in a lower layer than the waterproof sheet, on the inclined portion before the towing and moving step.

[0013] [8] The laying method according to any one of items [3] to [5], wherein the gripping width of the waterproof sheet by the multiple gripping devices differs according to the gripping position of the waterproof sheet.

[0014] [9] A method for laying a waterproof sheet on the inner surface of a bowl-shaped waste disposal site, wherein the inner surface comprises an inclined section, another inclined section located above the inclined section, and a step interposed between the inclined section and the other inclined section, and the method comprises a towing and moving step of towing and moving the waterproof sheet from a lower position and laying it on the inclined section, and a sheet connecting step of connecting the waterproof sheet laid on the inclined section in the towing and moving step and an existing waterproof sheet laid on the other inclined section to each other by work performed on the step. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a method for laying waterproof sheets that can reduce the work required to connect waterproof sheets to each other on an inclined surface. [Brief explanation of the drawing]

[0016] [Figure 1] This is a cross-sectional view showing a waste disposal site to which the waterproof sheet laying method of this embodiment is applied. [Figure 2] (a) is a cross-sectional view of the waterproofing layer, and (b) is a perspective view showing the protective mat installation process. [Figure 3] (a) is a perspective view showing the sheet placement process and the sheet connection process, and (b) is a perspective view showing the traction movement process. [Figure 4] (a) is a perspective view showing the towing process, and (b) is a perspective view showing the state after the completion of the towing process. [Figure 5] This is a perspective view showing an example of a clamp used as a gripping device. [Figure 6] (a) is a perspective view showing another example of a clamp used as a gripping device, and (b) is a side view showing it in use. [Figure 7] (a) is a perspective view showing the sheet addition step in the second embodiment, and (b) is a perspective view showing the state after completion of the subsequent traction movement step. [Figure 8] (a) is a perspective view showing a modified example of the traction movement step, and (b) is a plan view showing another modified example of the traction movement step. [Figure 9] (a) is a perspective view showing a modified example of the sheet arrangement step, and (b) is a cross-sectional view showing another example of the small step portion.

Embodiments for Carrying Out the Invention

[0017] [First Embodiment] Hereinafter, a first embodiment of a water-blocking sheet laying method according to the present invention will be described with reference to the drawings. The water-blocking sheet laying method of the present embodiment is carried out when constructing the waste disposal site 1 shown in FIG. 1.

[0018] The waste disposal site 1 is a management-type disposal site for landfill disposal of waste. Various wastes S containing organic substances and inorganic substances (salts, heavy metals) are discarded and landfilled in the storage tank 3 of the waste disposal site 1. The storage tank 3 has a shape that is dug downward in a mortar shape from the ground surface. Also, the waste disposal site 1 may be provided with a roof 5 that entirely covers the upper part of the storage tank 3.

[0019] The inner surface 7 of the storage tank 3 includes a flat bottom 11 that extends along a substantially horizontal plane, and side portions 13 that gradually rise outward from the ends of the bottom 11. The side portions 13 are configured by a plurality of inclined portions 15 and small step portions 17 connected alternately. The inclined portion 15 is a portion inclined at a gradient of, for example, 30 to 40 degrees toward the outside of the storage tank 3. The small step portion 17 is a portion formed to continuously connect between the inclined portions 15, 15. The small step portion 17 forms a substantially horizontal plane, but more precisely, the small step portion 17 has a slightly downward slope toward the bottom 11 side with a gradient smaller than that of the inclined portion 15. In FIG. 1, the side portion 13 includes five inclined portions 15 and four small step portions 17, but this is an example, and the number of inclined portions 15 and small step portions 17 can be appropriately changed.

[0020] When referring to the multiple inclined sections 15 that make up the side section 13, the lowest inclined section 15 is called inclined section 151, the second lowest inclined section 15 is called inclined section 152, and so on, up to the kth lowest inclined section 15. k Furthermore, when referring to the multiple step portions 17 that constitute the side portion 13 in a distinct manner, the step portion 17 interposed between the inclined portion 151 and the inclined portion 152 will be referred to as step portion 171, the step portion 17 interposed between the inclined portion 152 and the inclined portion 153 will be referred to as step portion 172, ..., inclined portion 15 k and inclined section 15 (k+1) The small step portion 17 interposed between them k Let's assume that.

[0021] The waste S disposed of in the storage tank 3 includes, for example, incinerated ash and fly ash solidified materials, organic sludge, inorganic sludge, wood chips, and slag generated at waste incineration facilities. In this type of controlled landfill, water is sprayed into the storage tank 3 to stabilize the waste S, which generates leachate. This leachate is collected from the bottom of the storage tank 3 through a collection pipe (not shown) and sent to another leachate treatment facility. The waste disposal site 1 is decommissioned after the landfill is completed and the waste S has stabilized.

[0022] The inner surface 7 of the storage tank 3 is covered with a waterproof layer 19 that blocks water from entering without any gaps. As shown in the cross-sectional view in Figure 2(a), the waterproof layer 19 has a multilayer structure in which waterproof sheets 21 and protective mats 23 are alternately laminated. For example, the waterproof layer 19 in this embodiment consists of a total of five layers: two layers of waterproof sheets 21 and three layers of protective mats 23. That is, the waterproof layer 19 is constructed by laying and laminating five sheet materials on the inner surface 7 of the storage tank 3 in the order of protective mat 23, waterproof sheet 21, protective mat 23, waterproof sheet 21, and protective mat 23. The waterproof sheet 21 is, for example, a polyethylene sheet with a thickness of about 1.5 mm, and the protective mat 23 is, for example, a short-fiber nonwoven fabric with a thickness of about 4 to 10 mm. Of these, the uppermost protective mat 23 is made of a short-fiber nonwoven fabric that has light-blocking properties. This waterproof layer 19 traps the leachate within the storage tank 3, preventing it from leaking into the ground 100 outside the storage tank 3.

[0023] Next, the method for laying the waterproof sheet according to this embodiment will be described. The waterproof sheet laying method according to this embodiment involves laying a waterproof sheet 21 on the inner surface 7 of the storage tank 3 during the construction of the waste disposal site 1. This waterproof sheet laying method includes the following steps: a protective mat laying step, a sheet placement step, a sheet connection step, a traction and movement step, and a second sheet connection step. In the following description, the upward and downward direction of the side portion 13 may be referred to as the Y direction, and the direction perpendicular to this (the direction in which the corner between the inclined portion 15 and the bottom portion 11 extends) may be referred to as the X direction, and the terms Y direction and X direction may be used.

[0024] [Protective mat installation process] In the protective mat laying process, a protective mat 23, which forms one of the waterproofing layers 19, is laid on the inner surface 7. Here, as shown in Figure 2(b), the protective mat 23 is laid without gaps on the bottom 11 and sides 13, at least within the area related to the waterproofing sheet laying method of this embodiment. The laying of the protective mat 23 can be carried out by a known laying method, and protective mats 23 of a predetermined size are laid without gaps on the bottom 11 and sides 13. As illustrated in the figure, one protective mat 23 is formed in the shape of a strip of a predetermined width (e.g., 5m width) that extends long in the Y direction. Here, the edges of adjacent protective mats 23 are arranged to overlap, but no joining process is performed on the edges. The subsequent sheet placement process, sheet connection process, and traction movement process are carried out on the protective mat 23 laid here. Furthermore, in the drawings (Figures 3, 4, etc.) used to explain the subsequent sheet placement process, sheet connection process, and towing and moving process, the protective mat 23 laid at this stage will not be shown in order to avoid making the drawings more complex.

[0025] [Sheet placement process] Next, in the sheet placement process, multiple waterproof sheets 21 are arranged side by side on the protective mat 23 at the bottom 11. Specifically, as shown in Figure 3(a), the waterproof sheets 21 are brought to the site as rolls 20, for example, about 5 m wide. These waterproof sheets 21 are unwound in the X direction at the bottom 11. Each waterproof sheet 21 is cut to a length of, for example, about 30 m, and multiple cut waterproof sheets 21 are arranged at the bottom 11 so that they are aligned in the width direction (Y direction). In this embodiment, it will be explained that three waterproof sheets 21, each 30 m long and 5 m wide, are cut. At the bottom 11, the widthwise edges of adjacent waterproof sheets 21 are overlapped by a predetermined width necessary for the joining work in the next process.

[0026] [Sheet joining process] Next, in the sheet joining process, the three waterproof sheets 21 arranged as described above are joined together in the width direction (Y direction). Specifically, the widthwise edges of the wrapped waterproof sheets 21 are joined together in a watertight manner along the entire length in the X direction. This joining process includes welding the edges of the waterproof sheets 21 together. Through this joining process, the three waterproof sheets 21 are integrated, forming a single watertight waterproof sheet enlarged to a size of 30m x 15m. This single waterproof sheet formed by the integration of the three waterproof sheets 21 and enlarged to a size of 30m x 15m will be referred to as "waterproof sheet 22" below.

[0027] The processing location for the above-mentioned joining operation is located at the bottom 11. That is, the overlapping portions of the edges of the three waterproof sheets 21 are located on the surface of the bottom 11. Therefore, this joining operation is performed at the bottom 11. Here, "the joining operation is performed at the bottom 11" means that the joining operation is performed with the worker P positioned at the bottom 11. That is, it means that the joining operation is performed with the worker P standing or sitting on the surface of the bottom 11.

[0028] [Towing movement process] Next, in the towing preparation process, as shown in Figure 3(b), a towing device 25 for towing the waterproof sheet 22 in the Y direction is first set on the waterproof sheet 22 which is placed on the bottom 11. The towing device 25 comprises a plurality of gripping devices 27, a plurality of cables 29, a suspension member 31, and a power unit 33. The gripping devices 27 of the towing device 25 are devices for gripping the edges of the waterproof sheet 22. Here, a plurality of gripping devices 27 are attached to the edge of the waterproof sheet 22 on the side closer to the inclined portion 151, at predetermined intervals in the X direction.

[0029] The suspension member 31 of the traction device 25 is a long, inflexible member exceeding the X-direction length (30m) of the waterproof sheet 22. For example, an H-beam or a single pipe may be used as the suspension member 31. Alternatively, the suspension member 31 may be a member forming a truss structure for weight reduction. Such a suspension member 31 is installed horizontally on the bottom 11 in a position extending in the X-direction between the waterproof sheet 22 and the inclined section 151. Each cable 29 of the traction device 25 is connected to each gripping device 27, and the other end of each cable 29 is connected to the suspension member 31 at the same interval as each gripping device 27 in the X-direction. The cable 29 may be a rope, a wire, or another type of cable-like material. The number of gripping devices 27 and cables 29 shown in the figure is an example and can be changed as appropriate.

[0030] The power unit 33 of the traction device 25 is a power source for traction of the waterproof sheet 22. In the example in Figure 3(b), two power units 33 are included in the traction device 25, but this is just an example, and the number of power units 33 can be changed as appropriate. The power unit 33 is installed on any small step 17 located above the current position (bottom 11) of the waterproof sheet 22. In the example in Figure 3(b), the power unit 33 is installed on small step 172, but it may also be installed on a smaller step 17 further up. Alternatively, the power unit 33 may be installed on small step 171, as long as it does not interfere with the laying of the waterproof sheet 22. The power unit 33 is a cable winding device for winding up the cable, for example, a winch. Alternatively, a sheet tensioning machine for deploying this type of waterproof sheet may be used as the power unit 33.

[0031] The power unit 33 is connected to the suspension member 31 via another cable 35. The power unit 33 can pull the suspension member 31 by winding up the cable 35, and in turn, can pull the waterproof sheet 22 via the multiple cables 29 and multiple gripping devices 27 connected to the suspension member 31. In the example shown in the figure, one power unit 33 is set to wind up two cables 35, but this is just one example, and the number of cables 35 per power unit 33 can be changed as appropriate. The total number of cables 35 can also be changed as appropriate. Using the traction device 25 described above, the waterproof sheet 22 placed on the bottom 11 can be lifted by sliding it along the inclined surface of the inclined section 151.

[0032] In this towing process, the waterproof sheet 22, which is placed on the bottom 11, is towed in the Y direction using the towing device 25 described above and laid on the inclined section 151. Specifically, after the towing device 25 is set up as described above, the power unit 33 is driven. This causes the cable 35 to be wound up, and as shown in Figure 4(a), the waterproof sheet 22 is dragged upwards on the inclined section 151. Since the coefficient of friction of the waterproof sheet 22 with respect to the protective mat 23 laid as the layer beneath the waterproof sheet 22 is about 0.3, the waterproof sheet 22 can slide on the protective mat 23 and move relatively smoothly on the inclined section 151. In addition, by using the suspension member 31 and arranging the gripping device 27 and cable 29 in a balanced manner in the X direction, the waterproof sheet 22 can be pulled evenly.

[0033] Then, when the waterproof sheet 22 is raised to the appropriate position, the winding by the power unit 33 is stopped, and each gripping device 27 of the traction device 25 is removed from the waterproof sheet 22, so that the waterproof sheet 22 is laid in place on the inclined section 151, as shown in Figure 4(b). Here, the waterproof sheet 22 is laid so that it covers the inclined section 151 from the top to the bottom. That is, the upper edge 22a of the laid waterproof sheet 22 is located on the step 171, and the lower edge 22b is located on the bottom 11. The size of the waterproof sheet 22 and the size of the inclined section 151 in the Y direction are set appropriately in advance to enable this laying state. In addition, here, another waterproof sheet 22' has already been laid on the inclined section 152 by previous laying work. Note that in Figure 3, the illustration of waterproof sheet 22' is omitted to avoid cluttering the diagram. Then, the upper edge 22a of the lifted waterproof sheet 22 is wrapped around the lower edge 22b' of the existing waterproof sheet 22' at the step 171.

[0034] [Second sheet joining process] Next, in the second sheet joining process, the upper edge 22a of the waterproof sheet 22 and the lower edge 22b' of the waterproof sheet 22', which are wrapped as described above, are joined together over their entire length to create a watertight bond. This integrates the newly laid waterproof sheet 22 with the previously laid waterproof sheet 22' above it. The processing location for this joining operation is located on the step section 171. That is, the overlapping portion of the upper edge 22a of the waterproof sheet 22 and the lower edge 22b' of the waterproof sheet 22' is located on the surface of the step section 171. Therefore, this joining operation is performed on the step section 171. Here, "the joining operation is performed on the step section 171" means that the joining operation is performed with the worker P positioned on the step section 171. That is, it means that the joining operation is performed with the worker P standing or sitting on the surface of the step section 171.

[0035] The waterproof sheet 22' may be laid on the inclined section 152 using the same laying method as the waterproof sheet 22. Alternatively, the waterproof sheet 22' may be laid on the inclined section 152 using a different laying method than that of the waterproof sheet 22.

[0036] The waterproof sheet laying method described above completes the laying of the waterproof sheet 22 on the inclined section 151. Furthermore, if this waterproof sheet laying method is repeated twice, two layers of waterproof sheet 22 and two layers of protective mat 23, which are included in the five layers of waterproof layer 19 (Figure 2), will be layered on the step section 171. Then, the top layer of protective mat 23 is laid on top of it, completing the waterproof layer 19 on the step section 171.

[0037] Next, an example of a gripping device 27 for the traction device 25 will be described. As a gripping device 27, for example, a clamp 60 as shown in Figure 5 can be used. The clamp 60 has a pair of clamping members 61 and 62 that sandwich the waterproof sheet 22 between them in the thickness direction. The rear ends of the clamping members 61 and 62 are connected by a hinge portion 63. The clamping members 61 and 62 are rotatable relative to each other so that their front ends open and close. The front end of the clamping member 62 protrudes further than the front end of the clamping member 61. The hinge portion 63 is provided with a U-shaped loop 65 that protrudes to the rear, and a cable 29 can be attached to this loop 65. A magnet 67 is attached to the inner surface of the clamping member 61, and a magnet 68 is attached to the inner surface of the clamping member 62 opposite it. The magnets 67 and 68 attract each other by magnetic force, which in turn attracts the clamping members 61 and 62, causing the waterproof sheet 22 to be strongly sandwiched between them. For example, neodymium magnets are used as the magnets 67 and 68.

[0038] Furthermore, in the region between the magnets 67, 68 and the hinge portion 63, clamping surfaces 64, 66 are formed on the inner surfaces of the clamping members 61, 62, respectively, which are treated to prevent slippage against the waterproof sheet 22. Specifically, the clamping surfaces 64, 66 are formed in a corrugated shape that interlocks with each other. The waterproof sheet 22, sandwiched between these clamping surfaces 64, 66, curves along the aforementioned corrugation, so it does not easily slip in the in-plane direction. Therefore, combined with the clamping force of the magnets 67, 68, the waterproof sheet 22 gripped by the clamp 60 does not easily come loose from the clamp 60. The anti-slip treatment of the clamping surfaces 64, 66 is not limited to being corrugated, and various known treatments that improve friction with the waterproof sheet 22 can be employed.

[0039] Furthermore, a handle 69 is provided on the outer surface of the tip of the clamping member 61, extending further toward the tip from that outer surface. The user can release the waterproof sheet 22 by, for example, stepping on the tip of the clamping member 62, grasping the handle 69, and pulling the clamping members 61 and 62 apart against the magnetic force of the magnets 67 and 68.

[0040] There are several variations of the clamp 60 with different gripping widths (dimensions in the hinge axis direction). In the traction movement process (Figure 4(a)), the gripping width of each clamp 60 attached to each position on the waterproof sheet 22 may differ depending on the gripping position of the waterproof sheet 22. That is, in the traction movement process, a clamp 60 with an appropriate gripping width is selected for each gripping position of the waterproof sheet 22 by each clamp 60. For example, a wider clamp 60 may be assigned to a gripping position where high tension is expected to act on the waterproof sheet 22 from the cable 29. This operation reduces the possibility of damage to the gripping positions of the waterproof sheet 22 by the clamp 60. A typical gripping width of the clamp 60 is, for example, 30 cm.

[0041] Instead of the clamp 60 described above, a clamp 70 as shown in Figure 6(a) may be used as the gripping device 27. The clamp 70 comprises a pair of clamping members 71 and 72, and the rear ends of the clamping members 71 and 72 are connected by a hinge portion 73. The clamping members 71 and 72 are rotatable relative to each other so that their front ends open and close. A U-shaped loop 75 is provided on the hinge portion 73 so as to protrude to the rear, and a cable 29 can be hung on this loop 75. A cylindrical core 74 can be clamped into the front ends of the clamping members 71 and 72. The front ends of the clamping members 71 and 72 are curved in a semi-cylindrical shape to correspond to the shape of the core 74. That is, the cylindrical core 74 is clamped in the space enclosed by the semi-cylindrical front end of the clamping member 71 and the semi-cylindrical front end of the clamping member 72. For example, a single pipe can be used as the core 74.

[0042] As shown in Figure 6(b), when the core 74 is sandwiched between the clamping members 71 and 72 with the edge of the waterproof sheet 22 wrapped around the core 74, the waterproof sheet 22 is sandwiched between the cylindrical outer surface of the core 74 and the cylindrical inner surfaces of the clamping members 71 and 72. The frictional force between the inner and outer surfaces of the cylinders prevents the waterproof sheet 22 from easily coming off the clamp 70. Similar to the clamp 60, multiple variations of the clamp 70 with different gripping widths may be provided.

[0043] Alternatively, a commercially available membrane puller may be used as the gripping device 27 instead of the clamps 60 and 70.

[0044] The effects and advantages of the waterproof sheet laying method of this embodiment will now be explained. As shown in Figures 3 and 4, this waterproof sheet laying method comprises a sheet connecting step in which multiple waterproof sheets 21 are connected to each other by work performed at the bottom 11, and a traction and movement step in which the waterproof sheets 22 enlarged by the sheet connecting step are towed and moved and laid on the inclined section 15. With this configuration, the waterproof sheets 22 that have been integrated by the connecting work at the bottom 11 are moved and laid together on the inclined section 15. Therefore, the number of places where waterproof sheets need to be connected to each other after laying is reduced, and the work of connecting waterproof sheets on the inclined surface of the inclined section 15 is reduced. In addition, the connecting work in the second sheet connecting step is also performed at the step 17.

[0045] Furthermore, in the waterproof sheet laying method of this embodiment, the traction movement step involves tractioning the waterproof sheet 22 from a lower position and laying it on the inclined section 15. After laying, the upper edge 22a and lower edge 22b of the waterproof sheet 22 are located on the flat section (bottom section 11 or small step section 17) that is situated between them with the inclined section 15 in between. In other words, after laying, the waterproof sheet 22 is laid so as to extend from the upper end to the lower end of the inclined section 15. As a result, there are no Y-direction cuts in the waterproof sheet 22 within the inclined section 15 after laying. Therefore, there is no need to perform connection work on the inclined section 15 to connect the laid waterproof sheets 22 in the Y direction; the Y-direction connection work can be performed on the flat section. Thus, the connection work of the waterproof sheets on the inclined surface of the inclined section 15 is reduced.

[0046] Thus, since the connection work of the waterproofing sheets is performed on the bottom 11 and steps 17, which are relatively close to the horizontal plane, the work efficiency is higher compared to, for example, when the connection work is performed on the inclined section 15. In other words, the inclined sections in a bowl-shaped waste disposal site generally have a large gradient, such as about 30 to 40 degrees. Compared to the inclined surface of such a large gradient inclined section 15, the connection work is performed on the bottom 11 and steps 17, which are relatively close to the horizontal plane, so accurate, fast, and safe work is possible.

[0047] In addition, according to the water-blocking sheet laying method of the present embodiment, although part of the connection work for connecting the water-blocking sheets 22 in the X direction has to be carried out on the inclined portion 15, the connection location and connection work can also be reduced by expanding the size of the water-blocking sheet 22 in the X direction (the cutting length of the water-blocking sheet 21 from the roll 20).

[0048] In addition, in the traction movement process in the present embodiment, the water-blocking sheet 22 at the bottom 11 was tractioned and moved to be laid on the inclined portion 151 directly above the bottom 11, but the present invention is not limited to this. That is, the traction movement process may be such that the water-blocking sheet 22 at the bottom 11 is tractioned and moved to be pulled up and laid on any inclined portion 15 (for example, inclined portion 152, inclined portion 153,... etc.) above the bottom 11. In this case, the power device 33 of the traction device 25 may be installed on the small step portion 17 located further above the inclined portion 15 where the water-blocking sheet 22 is to be laid.

[0049] Also, the water-blocking sheet laying method in the embodiment laid the water-blocking sheet 22 on one-stage inclined portion 15, but the present invention is not limited to this. For example, a water-blocking sheet 22 with a size that can be laid across a plurality of stages of inclined portions 15 is formed in the sheet arrangement process and the sheet connection process, and this water-blocking sheet 22 may be tractioned and moved in the region across a plurality of stages of inclined portions 15 in the traction movement process. That is, the water-blocking sheet 22 may be laid so as to extend across, for example, the small step portion 17 k , inclined portion 15 (k+1) , small step portion 17 (k+1) , inclined portion 15 (k+2) , small step portion 17 (k+2) ,... etc. Also, it is not essential that the upper edge 22a and the lower edge 22b of the water-blocking sheet 22 laid in the traction movement process are located on the small step portion 17. That is, the upper edge 22a and the lower edge 22b of the laid water-blocking sheet 22 may be located on the inclined portion 15.

[0050] Furthermore, in this embodiment, the sheet connection step involves connecting multiple waterproof sheets 21 to each other by work performed at the bottom 11 to form a waterproof sheet 22 on the bottom 11, and the traction movement step involves traction moving the waterproof sheet 22 and laying it on any inclined section 15 above the bottom 11. However, the present invention is not limited to this. That is, the sheet connection step may involve connecting multiple waterproof sheets 21 to each other by work performed at any small step 17 to form a waterproof sheet 22 on the small step 17, and the traction movement step may involve traction moving the waterproof sheet 22 and laying it on any inclined section 15 above the small step 17.

[0051] [Second Embodiment] Next, a second embodiment of the method for laying a waterproof sheet will be described. The waterproof sheet laying method of this embodiment comprises a protective mat laying step, a sheet arrangement step, a sheet connection step, and a traction and movement step, and further comprises a sheet extension step, which will be described below, instead of the second sheet connection step. The protective mat laying step, sheet arrangement step, sheet connection step, and traction and movement step in this embodiment are the same as in the first embodiment, so redundant explanations will be omitted.

[0052] [Sheet splicing process] As shown in Figure 7(a), after the protective mat laying process, sheet arrangement process, sheet joining process, and traction movement process are completed, the waterproof sheet 22 is laid so as described above, covering the inclined section 151 from the top to the bottom, with the upper edge 22a of the laid waterproof sheet 22 located on the step 171 and the lower edge 22b located on the bottom 11. From this state, in the sheet splicing process, the next waterproof sheet 42 to be laid is formed at the bottom 11 so as to be connected below the waterproof sheet 22. That is, three 30m x 5m waterproof sheets 21 are cut out and arranged on the bottom 11 in the same manner as in the sheet arrangement process in the first embodiment. The edge of these three waterproof sheets 21 closest to the inclined section 151 is wrapped over the lower edge 22b of the waterproof sheet 22 over its entire length in the X direction. Then, in the same manner as the sheet joining process, the three waterproof sheets 21 are integrated through the joining process to form a waterproof sheet 42 measuring 30m x 15m, and the edge of this waterproof sheet 42 on the inclined portion 151 side is connected to the lower edge 22b of the waterproof sheet 22 by welding. As a result, the waterproof sheet 42 is connected to the lower edge 22b side of the waterproof sheet 22.

[0053] [Towing movement process] Subsequently, the traction device 25 is set again on the upper edge 22a of the waterproof sheet 22, and the traction movement process is performed again. As the waterproof sheet 22 is pulled up in the Y direction by the traction device 25, the waterproof sheet 42 is also pulled up along the inclined section 151 in response. When the waterproof sheets 22 and 42 have been pulled up to the appropriate positions, the winding by the power unit 33 is stopped. At this point, as shown in Figure 7(b), the upper edge 42a of the waterproof sheet 42 has moved to the step 171, and the lower edge 42b of the waterproof sheet 42 has moved to a position closer to the inclined section 151 on the bottom 11. Note that the traction device 25 is not shown in Figure 7.

[0054] Subsequently, the aforementioned sheet splicing process is performed again, and a subsequent waterproof sheet is connected to the lower edge 42b of the waterproof sheet 42. From this point onward, the traction process and the sheet splicing process are repeated alternately, so that the waterproof sheets 22, 42, ... are sequentially spliced ​​together, and the waterproof sheets extend upward along the side 13. When the waterproof sheet 22 reaches the upper end of the side 13, the above repetition process ends. Finally, in an area with a width of 30 m in the X direction, waterproof sheets 22, 42, ... are laid on the inclined sections 151, 152, ... and the stepped sections 171, 172, ....

[0055] The method of laying the waterproof sheet according to this embodiment, as described above, provides the same effects and advantages as the method of laying the waterproof sheet according to the first embodiment.

[0056] Although the first and second embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and modifications may be made without changing the gist of each claim. Furthermore, it is possible to construct modified versions by utilizing the technical matters described in the embodiments described above. The configurations of each embodiment may be used in appropriate combinations.

[0057] For example, in the towing process, instead of the power unit 33, an operator may manually pull the lifting member 31. Alternatively, the operator may pull the lifting member 31 together with the power unit 33. Also, as shown in Figure 8(a), in the towing device 25, the lifting member 31 may be omitted and each cable 29 may be directly connected to the power unit 33. Furthermore, a power unit 33 or an operator may be provided on a one-to-one basis for each cable 29.

[0058] Furthermore, during the towing process, as shown in Figure 8(b), a tensioning process may be performed in which both edges of the waterproof sheet 22 in the X direction are pulled outward in a direction intersecting the towing direction (a direction having an X-direction component). This suppresses the occurrence of wrinkles and sagging in the waterproof sheet 22 due to disturbances during movement, and allows the waterproof sheet 22 to be laid on the inclined section 151 in a taut state. In the example in Figure 8(b), gripping devices 27 and cables 30 are attached to both edges of the waterproof sheet 22 in the X direction, and the cables 30 are pulled diagonally upward. In this case, the power unit 33 to which the upper end of the cable 30 is connected may be placed, for example, on the same step 17 as the power unit 33 to which the upper end of the cable 29 is connected. Note that the cable 30 may also be pulled in the X direction (horizontally).

[0059] Furthermore, in this embodiment, the processing location for connecting the waterproof sheets is located at the bottom 11, but this configuration is not essential; it is acceptable as long as the connecting work is performed at the bottom 11. That is, even if the overlapping portion of the edges of the waterproof sheets extends in the X direction at a position slightly higher than the bottom 11 (for example, about 50 cm higher), the connecting work can still be performed at the bottom 11. In this case, for example, a worker P can easily reach and access the overlapping portion while positioned at the bottom 11 and perform the connecting work. This state is also included in the aforementioned state of "the connecting work being performed at the bottom 11". The same applies to the aforementioned case of "the connecting work being performed at the step 17," in which case the overlapping portion of the edges of the waterproof sheets may extend in the X direction at a position slightly higher than the step 17 (for example, about 50 cm higher).

[0060] Furthermore, as shown in Figure 9(a), in the sheet arrangement process and the sheet splicing process, the waterproof sheet 21 of the roll 20 may be unwound in the Y direction at the bottom 11, and in the sheet joining process, multiple waterproof sheets 21 may be joined together in the X direction to form a waterproof sheet 22. Alternatively, in the sheet arrangement process, multiple waterproof sheets 21 may be arranged two-dimensionally in the XY direction at the bottom 11, and in the sheet joining process, these waterproof sheets 21 may be joined together in the X and Y directions to form a waterproof sheet 22. Also, as shown in Figure 9(b), a groove 17a extending in the X direction may be present in the step portion 17. In this case, a frame 34 for mounting the power unit 33 may be provided within the groove 17a. [Explanation of Symbols]

[0061] 1...Waste disposal site, 7...Interior surface, 11...Bottom (flat part), 15...Inclined part, 17...Small step (flat part), 21...Waterproof sheet, 23...Protective mat, 22, 22', 42...Waterproof sheet, 25...Traction device, 27...Gripping device, 29...Cable, 31...Lifting member, 33...Power device, 61...Clamping member, 62...Clamping member, 66...Clamping surface, 67, 68...Magnet.

Claims

1. A method for laying a waterproof sheet on the inner surface of a bowl-shaped waste disposal site, The inner surface comprises an inclined portion and a flat portion located below the inclined portion with a smaller gradient than the inclined portion. A sheet connecting step is performed on the flat section to connect a plurality of the waterproof sheets to each other, A laying method comprising a traction and movement step of towing and moving the water-impermeable sheet, which has been enlarged by the sheet connection step, and laying it on the inclined surface.

2. The installation method according to claim 1, wherein the flat portion is the bottom or a stepped portion of the inner surface of the waste disposal site.

3. The aforementioned towing and moving process is, The laying method according to claim 1, which is performed using a traction device comprising: a plurality of cables; a plurality of gripping devices attached to each of the cables for gripping the ends of the waterproof sheet; and a power device which is a power source for pulling the plurality of cables.

4. The aforementioned traction device is The installation method according to claim 3, further comprising a suspension member interposed in the connection between the power device and a plurality of cables and extending in a direction intersecting the traction direction, wherein the plurality of cables are connected to the suspension member at intervals in the direction of extension of the suspension member.

5. The aforementioned gripping device is The installation method according to claim 3, comprising: a pair of clamping members having clamping surfaces that are treated to prevent slipping against the waterproof sheet; and a magnet that generates a magnetic force in a direction that pulls the clamping surfaces together.

6. In the aforementioned towing and moving process, The installation method according to claim 1, wherein a tensioning process is performed to pull the waterproof sheet while it is being towed in a direction intersecting the towing direction.

7. The laying method according to claim 1, further comprising a mat laying step of laying a protective mat, which is to be installed in a lower layer than the waterproof sheet, on the inclined portion before the towing and moving step.

8. The laying method according to claim 3, wherein the gripping width of the waterproof sheet by the multiple gripping devices differs according to the gripping position of the waterproof sheet.

9. A method for laying a waterproof sheet on the inner surface of a bowl-shaped waste disposal site, The inner surface comprises an inclined portion, another inclined portion located above the aforementioned inclined portion, and a small step portion interposed between the aforementioned inclined portion and the other inclined portion. A towing and moving step is performed in which the waterproof sheet is pulled from a lower position and moved and laid on the inclined section. A laying method comprising a sheet connecting step, in which the waterproof sheet laid on the inclined section in the towing and moving step and an existing waterproof sheet laid on another inclined section are connected to each other by work performed on the step.

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