Impervious structure and manufacturing method of impervious structure

Abstract

To provide an impervious structure that can keep an original multilayer structure when temporarily placed on a sea surface.SOLUTION: A connection part 10a of each of multilayer integrated impervious sheets 2, 2 is firmly welded at five welding parts of a first upper side belt-like sheet welding part 19, a second upper side belt-like sheet welding part 20, a first lower side belt-like sheet welding part 21, a second lower side belt-like sheet welding part 22, and a lower side impervious sheet welding part 23. By this, even when an impervious structure 1a is influenced by winds and waves in a state of mooring and temporarily placing on a sea surface over a long period, risks of a protective mat 4B of the third layer (intermediate), an impervious sheet 5B of the fourth layer (lower side), and a protective mat 4C of the fifth layer (bottom edge) of each multilayer integrated impervious sheet 2 of the impervious structure 1a to be fallen off can be reduced, and an original multilayer structure can be kept.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a waterproof structure having a plurality of waterproof sheets and a protective mat, which is laid in a controlled sea surface disposal site or the like, and a method for manufacturing the waterproof structure. [Background technology]

[0002] Municipal waste, industrial waste such as incineration ash and coal ash, and other waste are buried in managed final disposal sites on land or offshore. For example, a managed offshore disposal site (hereinafter referred to as a disposal site) is constructed by laying a waterproof structure consisting of waterproof sheets and protective mats on the sides of the sloped or composite embankment that defines the disposal site, and, if necessary, on the bottom of the disposal site, to prevent water from leaking outside the site. Legally, the waterproof sheets must be installed in duplicate. This is based on a fail-safe design concept: even if one waterproof sheet is damaged by waste input as landfill material, as long as the other waterproof sheet remains intact, potentially contaminated waste and the water it comes into contact with can be prevented from leaking outside the site.

[0003] Crushed stone and other materials are placed on top of these two waterproof sheets to prevent them from floating up. The first waterproof sheet, located below the embankment, is subjected to relatively large external forces such as wave pressure from outside the embankment and hydrostatic pressure due to the difference in water level between the inside and outside of the embankment, so a thick layer of crushed stone and other weights is placed on top of it. On the other hand, the second waterproof sheet, laid further inside the first embankment, is not subjected to large uplift forces, so in many cases the crushed stone cross section on the second waterproof sheet is a thin layer, about 1m thick. The reason for installing the two waterproof sheets separately is that even if a small leak occurs in one of the waterproof sheets due to uncertainties during construction, as long as the separately installed waterproof sheet is able to seal it off, there will be no impact on the outside of the disposal site.

[0004] Furthermore, if the waste materials dumped into the disposal site contain rebar, steel frames, concrete fragments, or other materials that could damage the second waterproof sheet laid inside the embankment, leakage outside the disposal site will not occur if the first waterproof sheet underneath the second waterproof sheet is sound. Furthermore, with the accumulation of construction experience in recent years, construction reliability has improved. Therefore, in disposal sites that landfill waste materials, such as coal ash, that are unlikely to damage the waterproof sheet, the installation of a double waterproof sheet as an integrated unit has become common. Therefore, a protective mat is placed on the underside of the installed waterproof sheet to prevent damage from the base material placed on the surface on which the waterproof sheet is laid, and a protective mat is also placed on the top surface of the waterproof sheet to prevent damage from the loading material placed on top of the waterproof sheet.

[0005] In order to integrate the double waterproof sheet, it is necessary to integrate the upper and lower protective mats as well. A multi-layer integrated waterproof sheet is used, which, when laid, has a five-layer structure consisting of, from top to bottom, protective mat / waterproof sheet / protective mat / waterproof sheet / protective mat. This multi-layer integrated waterproof sheet is placed in the same position as the waterproof sheet below the embankment as the first waterproof sheet, and thick crushed stone or other materials are placed there to provide a large load that can withstand the uplift force caused by wave pressure and hydrostatic pressure. This eliminates the risk of damage to the multi-layer integrated waterproof sheet, even if rebar or other materials are buried in the ground. The use of this multi-layer integrated waterproof sheet reduces material costs and installation labor, making this type of waterproof structure desirable in the future.

[0006] To manufacture the above-mentioned multi-layer integrated waterproof sheet, the waterproof sheet and protective mat are first manufactured as raw rolls approximately 2 m wide at their respective manufacturing plants. Next, at a processing plant, strips of waterproof sheet and protective mat are unwound from these raw rolls, and the layers of protective mat / waterproof sheet / protective mat / waterproof sheet / protective mat are partially welded from above to produce a multi-layer integrated waterproof sheet (2 m wide). This multi-layer integrated waterproof sheet is then wound into a roll and packaged.

[0007] The partial welding process performed to form the multi-layer integrated waterproof sheet is a temporary measure taken to hold one layer of the protective mat when temporarily placed on the sea surface as a waterproof structure (described later) in order to reduce the number of times the waterproof sheet and protective mat are laid during construction at the disposal site, i.e., to allow for single laying, and does not have permanent welding strength. Packed rolls of multiple multi-layer integrated waterproof sheets are then transported to a processing plant or disposal site, and at the on-site land yard or a large outfitting ship, the widthwise ends of the strip-shaped multi-layer integrated waterproof sheet are welded together in an overlapping state, resulting in a large, panel-shaped (approximately rectangular) waterproof structure approximately 6 to 50 meters wide. Multiple such waterproof structures are then pulled out above sea level, and the ends of each waterproof structure are further joined together on the sea surface to form a single sheet that covers the entire target area, which is then laid by submerging it on the side of a revetment or the seabed.

[0008] Furthermore, at the connection portions connecting each of the multi-layer integrated waterproof sheets of the waterproof structure, a hook member made of the same material as the waterproof sheet is attached to the portion where the second waterproof sheet is superimposed on the top of each multi-layer integrated waterproof sheet, and this hook member protrudes upward while penetrating the portion where the first protective mat of each multi-layer integrated waterproof sheet is superimposed. Floating devices are attached to these hook members. After the waterproof structure is pulled out above the sea surface, it is temporarily moored on the sea surface by the floating devices until it is sunk. The floating devices provide sufficient buoyancy for the first protective mat and second waterproof sheet of each multi-layer integrated waterproof sheet of the waterproof structure to float to the sea surface. Based on past experience, the second waterproof sheet and the third protective mat placed below it can also float on the sea surface together with the upper two layers due to the partially welded processing.

[0009] However, in each multi-layer integrated waterproof sheet of a waterproof structure, the fourth-layer waterproof sheet, which is located below the third-layer protective mat, which is provided with buoyancy by a flotation device, is only joined to the third-layer protective mat by partial welding performed at the manufacturing factory of the multi-layer integrated waterproof sheet.As a result, if the waterproof structure is temporarily moored on the sea surface for an extended period of time and is subjected to the effects of wind and waves, the weight load of the fourth-layer waterproof sheet and the fifth-layer protective mat will cause the welded portion between the second-layer waterproof sheet and the third-layer protective mat, or between the third-layer protective mat and the fourth-layer waterproof sheet, of each multi-layer integrated waterproof sheet, to peel off, and whether or not the third-layer protective mat of each multi-layer integrated waterproof sheet is included, there is a risk that the fourth-layer waterproof sheet and the fifth-layer protective mat will fall off, making it difficult to lay the waterproof structure in its original multi-layer structure.

[0010] This is because, as mentioned above, the welding strength of the welds between the second-layer waterproof sheet and the third-layer protective mat, and between the third-layer protective mat and the fourth-layer waterproof sheet of each multi-layer integrated waterproof sheet is not required to be permanent, and therefore when the waterproof structure is temporarily moored on the sea surface, it is not sufficient to maintain the third-layer protective mat, fourth-layer waterproof sheet, and fifth-layer protective mat for a long period of time, and the welds between the second-layer waterproof sheet and the third-layer protective mat, or between the third-layer protective mat and the fourth-layer waterproof sheet, will peel off.

[0011] Incidentally, Patent Document 1 discloses a conventional technique for joining a waterproof sheet and a protective mat, in which a joining aid is a film-like material containing the same material as the waterproof sheet, and is integrally attached to the joint of the protective mat with the waterproof sheet using a well-known welding method or thermocompression method, and the joint of the protective mat is joined to the waterproof sheet by welding or thermocompression via this joining aid. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-188500 Summary of the Invention [Problem to be solved by the invention]

[0013] Even if the invention of the above-mentioned Patent Document 1 is adopted, there is a risk of peeling between the protective mat and the joining auxiliary material, which are made of different materials, and the above-mentioned problem cannot be solved.

[0014] The present invention has been made in consideration of the above points, and aims to provide a waterproof structure that can maintain its original multi-layer structure during the period of temporary placement when moored on the sea surface, and that improves work efficiency during manufacturing, as well as a method for manufacturing the same. [Means for solving the problem]

[0015] As a means for solving the above problem, the invention relating to the waterproof structure of claim 1 is a waterproof structure in which protective mats and waterproof sheets made of different materials are alternately stacked and partially welded together to connect the widthwise ends of a multi-layer integrated waterproof sheet consisting of three layers of protective mats and two layers of waterproof sheets, thereby ensuring a desired sheet area, and is characterized in that the connection portions between the widthwise ends of one multi-layer integrated waterproof sheet and the widthwise ends of the other multi-layer integrated waterproof sheet are configured such that the waterproof sheet located above each multi-layer integrated waterproof sheet is connected via an upper belt-shaped sheet made of the same material as the waterproof sheet, and the waterproof sheet located below one multi-layer integrated waterproof sheet is connected to the waterproof sheet located above the other multi-layer integrated waterproof sheet via a lower belt-shaped sheet made of the same material as the waterproof sheet, and the widthwise ends of the waterproof sheets located below each multi-layer integrated waterproof sheet are overlapping and connected.

[0016] In the invention of claim 1, the widthwise end of one multilayer integrated waterproof sheet can be firmly connected to the widthwise end of the other multilayer integrated waterproof sheet via upper and lower belt-shaped sheets made of the same material as the waterproof sheets. Hook members are welded to the waterproof sheet located above one of the multilayer integrated waterproof sheets. The hook members are made of the same material as the waterproof sheets, allowing for sufficient welding strength between the hook members and the waterproof sheets. This allows the waterproof structure to be adequately held in place by the flotation devices attached to the hook members when it is temporarily moored on the sea surface.

[0017] The invention relating to the waterproof structure of claim 2 is characterized in that, in the invention of claim 1, at least the upper belt-like sheet of the upper belt-like sheet and the lower belt-like sheet is formed in a long belt shape along the connection direction of the connection portion.

[0018] In the invention of claim 2, the upper band-shaped sheet can sufficiently ensure the connection strength between the waterproof sheet located above one multi-layer integrated waterproof sheet and the waterproof sheet located above the other multi-layer integrated waterproof sheet, i.e., the tensile strength, etc. in the connection range.

[0019] The invention of claim 3, which relates to a method for manufacturing a waterproof structure, is a method for manufacturing a waterproof structure in which protective mats and waterproof sheets made of different materials are alternately stacked and partially welded together to connect the widthwise ends of a multilayer integrated waterproof sheet consisting of three layers of protective mats and two layers of waterproof sheets, thereby ensuring a desired sheet area, and when connecting the widthwise ends of one multilayer integrated waterproof sheet to the widthwise ends of the other multilayer integrated waterproof sheet via an upper belt-like sheet and a lower belt-like sheet made of the same material as the waterproof sheets, the lower belt-like sheet and the waterproof sheet located below one of the multilayer integrated waterproof sheets overlap. a second welding step of welding the overlapping areas of the widthwise ends of the waterproof sheet located below each of the multilayer integrated waterproof sheets; a third welding step of welding the overlapping areas of the upper strip sheet and the waterproof sheet located above the other multilayer integrated waterproof sheet; a fourth welding step of welding the overlapping areas of the lower strip sheet and the waterproof sheet located above the other multilayer integrated waterproof sheet; and a fifth welding step of welding the overlapping areas of the upper strip sheet and the waterproof sheet located above one of the multilayer integrated waterproof sheets, in this order.

[0020] In the invention of claim 3, the first to fifth welding steps can be performed sequentially without any hindrance using an automatic upper and lower pressure welding machine equipped with a pair of upper and lower pressure rollers that sandwich and press the two overlapping welding target areas from above and below. Welding machines include automatic upper and lower pressure welding machines, upper pressure welding machines, and manual pressure welding machines. Among these, if the welding temperature and welding time per unit area are the same, the automatic upper and lower pressure welding machine produces the highest welding strength. As a result, in the invention of claim 3, the automatic upper and lower pressure welding machine can perform the first to fifth welding steps sequentially without any hindrance, thereby firmly connecting the waterproof sheets located above and below each multi-layer integrated waterproof sheet via the upper belt-shaped sheet and the lower belt-shaped sheet. In the invention of claim 3, the five welding locations achieved in the first to fifth welding steps form a welding line. Furthermore, the three locations of the welded portion in the second welding step, the welded portion in the third welding step, and the welded portion in the fifth welding step form an inspection line for inspecting the welding quality.

[0021] The invention relating to the waterproof structure of claim 4 is a waterproof structure in which protective mats and waterproof sheets made of different materials are alternately stacked and partially welded together to connect the widthwise ends of a multi-layer integrated waterproof sheet consisting of three layers of protective mats and two layers of waterproof sheets, thereby ensuring a desired sheet area, and is characterized in that the connection portion between the widthwise end of one multi-layer integrated waterproof sheet and the widthwise end of the other multi-layer integrated waterproof sheet is formed by overlapping and connecting the widthwise ends of the waterproof sheet located on the upper side of each multi-layer integrated waterproof sheet, and the waterproof sheet located on the lower side of one multi-layer integrated waterproof sheet and the waterproof sheet located on the upper side of the other multi-layer integrated waterproof sheet are connected via a strip-shaped sheet made of the same material as the waterproof sheets, and the widthwise ends of the waterproof sheets located on the lower side of each multi-layer integrated waterproof sheet are overlapped and connected.

[0022] In the invention of claim 4, each waterproof sheet of one multilayer integrated waterproof sheet can be firmly connected to each waterproof sheet of the other multilayer integrated waterproof sheet via a strip-shaped sheet made of the same material as the waterproof sheets. Also, in the invention of claim 4, only one strip-shaped sheet is needed, which reduces the manufacturing cost of the waterproof structure.

[0023] The invention relating to the waterproof structure of claim 5 is characterized in that, in the invention of claim 4, the strip-shaped sheet is formed into a long strip along a direction perpendicular to the connection direction of the connection portion, and multiple strip-shaped sheets are arranged at intervals from each other along the connection direction.

[0024] In the invention of claim 5, the strip-shaped sheets are arranged at intervals along the connection direction between the widthwise end of one multi-layer integrated waterproof sheet and the widthwise end of the other multi-layer integrated waterproof sheet, with the necessary strength to prevent the third layer protective mat, the fourth layer waterproof sheet and the fifth layer protective mat from peeling off and falling off.Therefore, the welding length is shorter than in a configuration in which the strip-shaped sheets are welded without any intervals along the connection direction between the widthwise end of one multi-layer integrated waterproof sheet and the widthwise end of the other multi-layer integrated waterproof sheet, and as a result, the time required for the welding work can be reduced.

[0025] The invention of claim 6, which relates to a method for manufacturing a waterproof structure, is a method for manufacturing a waterproof structure in which protective mats and waterproof sheets made of different materials are alternately stacked and partially welded together to connect the widthwise ends of a multi-layer integrated waterproof sheet consisting of three layers of protective mats and two layers of waterproof sheets, thereby ensuring a desired sheet area, and when connecting the widthwise end of one of the multi-layer integrated waterproof sheets to the widthwise end of the other multi-layer integrated waterproof sheet via a strip-shaped sheet made of the same material as the waterproof sheets, The method is characterized in that the steps of welding are carried out in the following order: a first welding step of welding the overlapping portions of the waterproof sheet located below the strip-shaped sheet with the waterproof sheet located below each of the multilayer integrated waterproof sheets; a second welding step of welding the overlapping portions of the widthwise ends of the waterproof sheet located below each of the multilayer integrated waterproof sheets; a third welding step of welding the overlapping portions of the strip-shaped sheet with the waterproof sheet located above the other multilayer integrated waterproof sheet; and a fourth welding step of welding the overlapping portions of the widthwise ends of the waterproof sheet located above each of the multilayer integrated waterproof sheets.

[0026] In the invention of claim 6, the welded portions in the first to fourth welding steps can be welded by the above-mentioned automatic up-and-down pressure welding machine. And, in the invention of claim 6, the number of welding steps can be reduced as much as possible, and the first to fourth welding steps can be carried out in order without any problems by the automatic up-and-down pressure welding machine, so the time required for the welding work can be shortened while ensuring the connection strength of the waterproof sheets located above and below each multi-layer integrated waterproof sheet.

[0027] The invention of claim 7, which relates to a method for manufacturing a waterproof structure, is a method for manufacturing a waterproof structure in which protective mats and waterproof sheets made of different materials are alternately stacked and partially welded to connect the widthwise ends of a multi-layer integrated waterproof sheet consisting of three layers of protective mats and two layers of waterproof sheets, thereby ensuring a desired sheet area, and when connecting the widthwise end of one multi-layer integrated waterproof sheet to the widthwise end of the other multi-layer integrated waterproof sheet via a strip-shaped sheet made of the same material as the waterproof sheets, The method is characterized in that the steps of welding are carried out in the following order: a first welding step of welding the overlapping portions of the widthwise ends of the waterproof sheet located on the side of one of the multilayer integrated waterproof sheets; a second welding step of welding the overlapping portions of the waterproof sheet located on the lower side of one of the multilayer integrated waterproof sheets and the strip-shaped sheet; a third welding step of welding the overlapping portions of the strip-shaped sheet and the waterproof sheet located on the upper side of the other multilayer integrated waterproof sheet; and a fourth welding step of welding the overlapping portions of the widthwise ends of the waterproof sheets located on the upper side of each of the multilayer integrated waterproof sheets.

[0028] In the seventh aspect of the invention, the welded portions in the first welding step and the welded members in the fourth welding step can be welded by the above-mentioned automatic upper and lower pressure welding machine. The welded portions in the second welding step and the welded portions in the third welding step can be welded by an automatic upper pressure welding machine having a pressure roller on the upper side, or a manual pressure welding machine. The seventh aspect of the invention can reduce the number of welding steps as much as possible, and furthermore, the first through fourth welding steps can be carried out in order without any hindrance by the automatic upper and lower pressure welding machine, the automatic upper pressure welding machine, and the manual pressure welding machine. This makes it possible to shorten the time required for the welding work while ensuring the connection strength of the waterproof sheets located above and below each of the multi-layer integrated waterproof sheets.

[0029] In the inventions of claims 6 and 7, the four locations of the first to fourth welding steps form welding lines. Also, two locations, the welded portion of the first or second welding step and the welded portion of the fourth welding step, form inspection lines for inspecting the welding quality. In this way, by reducing the number of welding lines and inspection lines as much as possible, it is possible to improve work efficiency and reduce construction costs. [Effects of the Invention]

[0030] According to the waterproof structure and manufacturing method of the present invention, when the structure is temporarily moored on the sea surface, the original multi-layer structure can be maintained during the temporary placement period without the layers peeling or falling off, and the work efficiency when manufacturing the waterproof structure can be improved. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a plan view of a waterproof structure according to the first and second embodiments of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the multilayer integrated waterproof sheet used in the first and second waterproof structures. [Figure 3] Figure 3 is a cross-sectional view of the connection portion between the widthwise end of one multilayer integrated waterproof sheet and the widthwise end of the other multilayer integrated waterproof sheet in the waterproof structure according to the first embodiment. [Figure 4] Figure 4 is a plan view of the connection portion between the widthwise end of one multilayer integrated waterproof sheet and the widthwise end of the other multilayer integrated waterproof sheet in the waterproof structure according to the first embodiment. [Figure 5] Figure 5 is a manufacturing method for a waterproof structure according to the first embodiment, showing the construction method in stages for connecting the widthwise end of one multilayer integrated waterproof sheet to the widthwise end of the other multilayer integrated waterproof sheet. [Figure 6] FIG. 6 is a perspective view of an existing automatic up-and-down pressure welding machine. [Figure 7] FIG. 7 is a perspective view of an existing automatic upper pressure welding machine. [Figure 8]FIG. 8 is a perspective view of an existing manual pressure welding machine. [Figure 9] FIG. 9 is a perspective view of the connection portion between the widthwise end portion of one multilayer integrated waterproof sheet and the widthwise end portion of the other multilayer integrated waterproof sheet in the waterproof structure according to the first embodiment. [Figure 10] Figure 10 is a cross-sectional view of the connection portion between the widthwise end of one multilayer integrated waterproof sheet and the widthwise end of the other multilayer integrated waterproof sheet in the waterproof structure according to the second embodiment. [Figure 11] Figure 11 is a waterproof structure according to the second embodiment, and is a plan view of the connection portion between the widthwise end portion of one multilayer integrated waterproof sheet and the widthwise end portion of the other multilayer integrated waterproof sheet, where (a) is a diagram showing a state in which a long strip-shaped sheet is arranged along the connection direction of the connection portion, and (b) is a diagram showing a state in which multiple long strip-shaped sheets are arranged at intervals from each other along the connection direction of the connection portion in a direction perpendicular to the connection direction of the connection portion. [Figure 12] Figure 12 is a manufacturing method for a waterproof structure according to the second embodiment, and is a diagram showing in stages the construction method according to the first embodiment when connecting the widthwise end of one multilayer integrated waterproof sheet to the widthwise end of the other multilayer integrated waterproof sheet. [Figure 13] Figure 13 is a manufacturing method for a waterproof structure according to the second embodiment, and is a diagram showing in stages the construction method according to the second embodiment when connecting the widthwise end of one multilayer integrated waterproof sheet to the widthwise end of the other multilayer integrated waterproof sheet. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. The waterproof structures 1a, 1b according to the first and second embodiments of the present invention are installed on the sides of, for example, inclined breakwaters or composite breakwaters, and on the bottom of a managed marine disposal site. The waterproof structures 1a, 1b according to the first and second embodiments are constructed in an on-site land yard or on a large outfitting ship by connecting the widthwise ends of multiple strip-shaped multilayer integrated waterproof sheets 2, 2 at connecting portions 10a, 10b, as shown in FIG. 1, to form a panel shape (substantially rectangular) with a desired sheet area. The widthwise dimension (left-right direction in FIG. 1) of the multiple multilayer integrated waterproof sheets 2, 2 employed in the waterproof structures 1a, 1b according to the first and second embodiments is approximately 2 m. The waterproof structures 1a, 1b according to the first and second embodiments have a width of approximately 6 to 50 m in the left-right direction in FIG. 1 and a length of approximately 10 to 200 m in the up-down direction in FIG. 1.

[0033] First, a waterproof structure 1a according to the first embodiment will be described with reference to FIGS. As shown in FIG. 2, the multilayer integrated waterproof sheet 2 is constructed by stacking five layers of protective mat 4A, waterproof sheet 5A, protective mat 4B, waterproof sheet 5B, and protective mat 4C from top to bottom, and partially welding and integrating them at intervals in the width direction (as indicated by the dashed dotted line in FIG. 1). The protective mats 4A to 4C are made of materials such as long-fiber nonwoven fabric, short-fiber nonwoven fabric, and pile felt. The waterproof sheets 5A and 5B have the desired waterproofing properties and are made of materials such as vinyl chloride, polyethylene, or other polymeric materials. The thickness of the waterproof sheets 5A and 5B is set within the range of 1.5 to 10 mm. In this embodiment, the thickness of the waterproof sheets 5A and 5B is 3 to 4 mm.

[0034] As described above, the multi-layer integrated waterproof sheet 2 is formed by joining and integrating the protective mats 4A-4C and the waterproof sheets 5A, 5B, which are made of different materials, by partially welding the contact surfaces between the waterproof sheets 5A, 5B and the protective mats 4A-4C, but the bonding strength is only sufficient to hold one layer of the protective mat 4C, which is the lowest layer, when the waterproof structure 1a is temporarily placed on the sea surface, and the bonding strength is only sufficient to simply integrate the protective mats 4A-4C and the waterproof sheets 5A, 5B. As a result, the bonding strength is not strong enough to withstand a load in the peeling direction that is greater than the strength of one layer of the protective mat 4C, and is not reliable as a long-term bonding strength.

[0035] As shown in Figs. 1 and 3, in the waterproof structure 1a according to the first embodiment, the widthwise end of one multilayer integrated waterproof sheet 2 and the widthwise end of the other multilayer integrated waterproof sheet 2 are connected by a connection portion 10a. Referring to Fig. 3, the connection portion 10a is configured, in particular, so as to be connected as follows: The upper waterproof sheets 5A, 5A located in the second layer (upper side) of each of the multilayer integrated waterproof sheets 2, 2 are connected via an upper strip-shaped sheet 13. Furthermore, the lower waterproof sheet 5B located in the fourth layer (lower side) of one multilayer integrated waterproof sheet 2 (the multilayer integrated waterproof sheet 2 on the right side as you face Fig. 3) is connected to the upper waterproof sheet 5A located in the second layer (upper side) of the other multilayer integrated waterproof sheet 2 (the multilayer integrated waterproof sheet 2 on the left side as you face Fig. 3) via a lower strip-shaped sheet 14. Furthermore, the widthwise ends of the lower waterproof sheets 5B, 5B located in the fourth layer (lower side) of each of the multi-layer integrated waterproof sheets 2, 2 are overlapped and connected.

[0036] The upper belt-like sheet 13 and the lower belt-like sheet 14 are made of the same material as the waterproof sheets 5A and 5B. As shown in Figure 4, the upper belt-like sheet 13 and the lower belt-like sheet 14 are formed in a long belt shape along the connection direction of the connection parts 10a. The length along the longitudinal direction of the upper belt-like sheet 13 and the lower belt-like sheet 14 is approximately the same as the length along the connection direction of the connection parts 10a. It is also possible to adopt a configuration in which only the lower belt-like sheet 14 is formed in a long belt shape along a direction perpendicular to the connection direction of the connection parts 10a, and multiple lower belt-like sheets 14 are arranged at intervals from each other along the connection direction of the connection parts 10a.

[0037] The connection portion 10a will be described in detail with reference to Figure 3. The connection portion 10a includes an upper end protective mat welding portion 18 where the widthwise ends of the protective mats 4A, 4A located on the first layer (top end) of each multilayer integrated waterproof sheet 2, 2 are overlapped and welded together, a first upper strip-shaped sheet welding portion 19 where the widthwise end of the upper waterproof sheet 5A located on the second layer (top side) of one multilayer integrated waterproof sheet 2 (the multilayer integrated waterproof sheet 2 on the right side as you face Fig. 3) and one widthwise end of the upper strip-shaped sheet 13 are overlapped and welded together, a second upper strip-shaped sheet welding portion 20 where the other widthwise end of the upper strip-shaped sheet 13 and a portion slightly inward from the widthwise end of the upper waterproof sheet 5A located on the second layer (top side) of the other multilayer integrated waterproof sheet 2 (the multilayer integrated waterproof sheet 2 on the left side as you face Fig. 3) are overlapped and welded together, and a second upper strip-shaped sheet welding portion 21 where the other widthwise end of the upper strip-shaped sheet 13 and a portion slightly inward from the widthwise end of the upper waterproof sheet 5A located on the second layer (top side) of the other multilayer integrated waterproof sheet 2 (the multilayer integrated waterproof sheet 2 on the left side as you face Fig. 3) are overlapped and welded together. 2 and the other widthwise end of the lower band-shaped sheet 14 are overlapped and welded together; a second lower band-shaped sheet welding area 22 where one widthwise end of the lower band-shaped sheet 14 and a portion slightly inward from the widthwise end of the lower waterproof sheet 5B located in the fourth layer (lower side) of one of the multilayer integrated waterproof sheets 2 are overlapped and welded together; a lower waterproof sheet welding area 23 where the widthwise ends of the lower waterproof sheets 5B, 5B located in the fourth layer (lower side) of each multilayer integrated waterproof sheet 2, 2 are overlapped and welded together; and a lower end protective mat welding area 24 where the widthwise ends of the protective mats 4A, 4A located in the fifth layer (lower end) of each multilayer integrated waterproof sheet 2, 2 are overlapped and welded together.

[0038] Next, a manufacturing method of the waterproof structure 1a according to the first embodiment, i.e., an installation method (connection method) for the connection region 10a of each multilayer integrated waterproof sheet 2, 2, will be described based on Fig. 5, with appropriate reference to Figs. 6 to 8. Note that the protective mats 4A, 4B, and 4C are not shown in Fig. 5. The connection region 10a is welded in the following order: lower end protective mat welding region 24 shown in Fig. 3 → second lower belt-shaped sheet welding region 22 (first welding step) → lower waterproof sheet welding region 23 (second welding step) → second upper belt-shaped sheet welding region 20 (third welding step) → first lower belt-shaped sheet welding region 21 (fourth welding step) → first upper belt-shaped sheet welding region 19 (fifth welding step) → upper end protective mat welding region 18 shown in Fig. 3. Therefore, for welding, an automatic upper and lower pressure welding machine 27 having a pair of upper and lower pressure rollers 32, 33 as shown in Figure 6, an automatic upper pressure welding machine 28 having an upper pressure roller 40 as shown in Figure 7, or a manual pressure welding machine 29 as shown in Figure 8 is used.

[0039] As shown in Fig. 6, the automatic vertical pressure welding machine 27 is generally configured to include a pair of upper and lower pressure rollers 32, 33 that sandwich and press two overlapping welding target areas from above and below, and a hot air supply pipe 35 with an air outlet 34 disposed between each welding target area and that supplies hot air from the air outlet 34 between each welding target area. Note that in Fig. 5, the air outlet 34 is shown disposed facing the space between each welding target area, but in reality, the air outlet 34 is inserted between each welding target area so that the tip of the air outlet 34 is positioned between each welding target area. The automatic vertical pressure welding machine 27 is self-propelled, and its travel speed is basically constant. The hot air temperature and travel speed are appropriately set depending on on-site conditions such as air temperature to ensure welding quality. The automatic upper and lower pressure welding machine 27 moves at a predetermined speed, supplies hot air between the areas to be welded from the hot air supply pipe 35, and welds the two areas to be welded by pressing them from above and below using a pair of upper and lower pressure rollers 32, 33.

[0040] In the automatic vertical pressure welding machine 27, the pair of upper and lower pressure rollers 32, 33 can be arranged above and below the two parts to be welded, and the outlet 34 of the hot air supply pipe 35 must be arranged between the parts to be welded. The automatic vertical pressure welding machine 27 also includes the hot air supply pipe 35, an arm 36 connected to the lower pressure roller 33, and a main body part 37 arranged to straddle the arm 36 toward the hot air supply pipe 35, and the pair of upper and lower pressure rollers 32, 33 must be arranged over the parts to be welded so as to avoid these.

[0041] 7, the automatic upper pressure welding machine 28 is generally configured to include an upper pressure roller 40 that is self-propelled and presses two overlapping parts to be welded from above, and a hot air supply pipe 42 that has an air outlet 41 disposed between each of the parts to be welded and supplies hot air from the air outlet 41 between the parts to be welded. The automatic upper pressure welding machine 28 self-propels at a predetermined speed, supplies hot air from the hot air supply pipe 42 between the parts to be welded, and presses the parts to be welded from above with the upper pressure roller 40, thereby welding them together. The automatic upper pressure welding machine 28 can be used as long as it can press the top surfaces of the parts to be welded with the upper pressure roller 40 and the air outlet 41 of the hot air supply pipe 42 can be easily disposed between the parts to be welded.

[0042] As shown in FIG. 8 , the manual pressure welding machine 29 has a hot air supply pipe 44 through which hot air is supplied and a grip 45 that extends axially from the axial end of the hot air supply pipe 44 and is held by an operator. The operator holds the grip 45 of the manual pressure welding machine 29 and applies pressure to the welding target area from above with the tip of the hot air supply pipe 44, or with the tip of a pressing cylinder or the like attached to the tip of the hot air supply pipe 44, while supplying hot air from the hot air supply pipe 44, thereby welding the two together. The manual pressure welding machine 29 can be used as long as the area above the top surface of the welding target area is open. Note that, if the welding temperature (hot air temperature) and welding time per unit area are the same, the weld strength produced by the upper / lower pressure automatic welding machine 27 is generally greater than the weld strength produced by the upper pressure automatic welding machine 28.

[0043] Then, as shown in Figure 5(a), in the first welding step, the lower surface of one widthwise end of the lower belt-shaped sheet 14 is brought into contact with the upper surface of a portion slightly inward from the widthwise end of the waterproof sheet 5B located below one of the multi-layer integrated waterproof sheets 2, and the connection portion 10a is welded using an automatic upper and lower pressure welding machine 27 to form a second lower belt-shaped sheet welding portion 22.

[0044] Specifically, in the first welding step, the widthwise end of waterproof sheet 5B of one of the multilayer integrated waterproof sheets 2 is raised together with the lower strip sheet 14 so that the arms 36 and main body 37 of the automatic vertical pressure welding machine 27 do not interfere with the waterproof sheet 5B or lower strip sheet 14 located below one of the multilayer integrated waterproof sheets 2, and the lower pressure roller 33 of the automatic vertical pressure welding machine 27 is inserted below the waterproof sheet 5B located below one of the multilayer integrated waterproof sheets 2 from the widthwise end side of said waterproof sheet 5B to abut against the underside of said waterproof sheet 5B, while the upper pressure roller 32 is positioned so as to abut against the upper surface of the lower strip sheet 14. In addition, the hot air supply pipe 35 of the automatic vertical pressure welding machine 27 is positioned so that its outlet 34 is located between the waterproof sheet 5B located below one of the multilayer integrated waterproof sheets 2 and the lower strip sheet 14. Then, the automatic vertical pressure welding machine 27 is driven and self-propelled along the connecting direction of the connecting portion 10a, whereby the second lower belt-shaped sheet welding portion 22 is formed.

[0045] Next, as shown in Figure 5(b), in the second welding step, the lower surface of the waterproof sheet 5B located below one of the multi-layer integrated waterproof sheets 2 and the upper surface of the waterproof sheet 5B located below the other multi-layer integrated waterproof sheet 2 are brought into contact and welded together using an automatic upper and lower pressure welding machine 27, thereby forming the lower waterproof sheet welding portion 23.

[0046] Specifically, in the second welding step, the widthwise ends of the waterproof sheets 5B, 5B of each multilayer integrated waterproof sheet 2 are raised together with the lower strip sheet 14 so that the arms 36 and main body 37 of the automatic vertical pressure welding machine 27 do not interfere with the waterproof sheets 5B, 5B and the lower strip sheet 14 of each multilayer integrated waterproof sheet 2, and the lower pressure roller 33 of the automatic vertical pressure welding machine 27 is inserted below the waterproof sheet 5B located below the other multilayer integrated waterproof sheet 2 and abuts against the underside of the waterproof sheet 5B. In addition, the lower strip sheet 14 is turned up to expose the top surface of the waterproof sheet 5B located below one of the multilayer integrated waterproof sheets 2, and the upper pressure roller 32 of the automatic vertical pressure welding machine 27 is abutted against that top surface.

[0047] Furthermore, the hot air supply pipe 35 of the automatic vertical pressure welding machine 27 is positioned so that its outlet 34 is located between the waterproof sheets 5B, 5B located on the lower side of each multilayer integrated waterproof sheet 2. At this time, one of the overlapping upper waterproof sheets 5B is located above the arm 36 of the automatic vertical pressure welding machine 27, and the other lower waterproof sheet 5B is located below the arm 36 of the automatic vertical pressure welding machine 27, before being welded by the upper and lower pressure rollers 32, 32 of the automatic vertical pressure welding machine 27. The automatic vertical pressure welding machine 27 is then driven and caused to move freely along the connection direction of the connection portion 10a, thereby forming the lower waterproof sheet welded portion 23.

[0048] Next, as shown in Figure 5(c), in the third welding step, the underside of the other widthwise end of the upper belt-shaped sheet 13 is brought into contact with the upper surface of a portion slightly inward from the widthwise end of the waterproof sheet 5A located above the other multi-layer integrated waterproof sheet 2, and welded together using an automatic up-and-down pressure welding machine 27 to form a second upper belt-shaped sheet welding portion 20.

[0049] Specifically, in the third welding step, the widthwise end of the upper waterproof sheet 5A of the other multilayer integrated waterproof sheet 2 is raised together with the upper belt sheet 13 so that the arms 36 and main body 37 of the automatic vertical pressure welding machine 27 do not interfere with the waterproof sheet 5A or the upper belt sheet 13 of the other multilayer integrated waterproof sheet 2, and the lower pressure roller 33 of the automatic vertical pressure welding machine 27 is inserted from the widthwise end side of the upper waterproof sheet 5A of the other multilayer integrated waterproof sheet 2 below the waterproof sheet 5A so as to abut against the underside of the waterproof sheet 5A, while the upper pressure roller 32 is positioned so as to abut against the upper surface of the upper belt sheet 13. In addition, the hot air supply pipe 35 of the automatic vertical pressure welding machine 27 is positioned so that its outlet 34 is located between the upper waterproof sheet 5A of the other multilayer integrated waterproof sheet 2 and the upper belt sheet 13. Then, the automatic vertical pressure welding machine 27 is driven and self-propelled along the connecting direction of the connecting portion 10a, whereby the second upper belt-shaped sheet welding portion 20 is formed.

[0050] Next, as shown in Figure 5(d), in the fourth welding step, the underside of the widthwise end of the waterproof sheet 5A located above the other multi-layer integrated waterproof sheet 2 is brought into contact with the upper surface of the other widthwise end of the lower belt-shaped sheet 14 and welded together by an automatic upper and lower pressure welding machine 27 to form the first lower belt-shaped sheet welding portion 21.

[0051] Specifically, in the fourth welding step, the waterproof sheet 5A located above the other multilayer integrated waterproof sheet 2 is raised at its widthwise end together with the lower belt sheet 14 so that the arms 36 and main body 37 of the automatic vertical pressure welding machine 27 do not interfere with the waterproof sheet 5A or upper belt sheet 13 of the other multilayer integrated waterproof sheet 2, and the lower pressure roller 33 of the automatic vertical pressure welding machine 27 is inserted below the lower belt sheet 14 and abutted against the underside of the lower belt sheet 14. Furthermore, the upper belt sheet 13 is turned up to expose the top surface of the waterproof sheet 5A located above the other multilayer integrated waterproof sheet 2, and the upper pressure roller 32 of the automatic vertical pressure welding machine 27 is abutted against that top surface.

[0052] Furthermore, the hot air supply pipe 35 of the automatic vertical pressure welding machine 27 is positioned so that its outlet 34 is located between the waterproof sheet 5A located on the upper side of the other multilayer integrated waterproof sheet 2 and the lower belt-like sheet 14. At this time, the other upper overlapping waterproof sheet 5A is positioned above the arm 36 of the automatic vertical pressure welding machine 27, and the lower lower belt-like sheet 14 is positioned below the arm 36 of the automatic vertical pressure welding machine 27, before being welded by the upper and lower pressure rollers 32, 32 of the automatic vertical pressure welding machine 27. The automatic vertical pressure welding machine 27 is then driven and made to travel automatically along the connection direction of the connection region 10a, thereby forming the first lower belt-like sheet welded region 21.

[0053] Next, as shown in Figure 5(e), in the fifth welding step, the lower surface of the widthwise end of the waterproof sheet 5A located on the upper side of one of the multi-layer integrated waterproof sheets 2 is brought into contact with the upper surface of one widthwise end of the upper strip sheet 13 and welded together using an automatic upper and lower pressure welding machine 27 to form the first upper strip sheet welding portion 19.

[0054] Specifically, in the fifth welding step, the waterproof sheet 5A located on the upper side of one of the multilayer integrated waterproof sheets 2 is raised at its widthwise end together with the upper belt sheet 14, and the lower pressure roller 33 of the automatic vertical pressure welding machine 27 is inserted below the upper belt sheet 13 to abut against the underside of the upper belt sheet 13, so that the arm 36 and main body 37 of the automatic vertical pressure welding machine 27 do not interfere with the waterproof sheet 5A and upper belt sheet 13 of one of the multilayer integrated waterproof sheets 2.

[0055] Furthermore, the hot air supply pipe 35 of the automatic vertical pressure welding machine 27 is arranged so that its outlet 34 is located between the waterproof sheet 5A located on the upper side of one of the multilayer integrated waterproof sheets 2 and the upper belt-shaped sheet 13. At this time, before being welded by the upper and lower pressure rollers 32, 32 of the automatic vertical pressure welding machine 27, the one upper waterproof sheet 5A of the overlapping sheets is located above the arm 36 of the automatic vertical pressure welding machine 27, and the lower upper belt-shaped sheet 13 is located below the arm 36 of the automatic vertical pressure welding machine 27. The automatic vertical pressure welding machine 27 is then driven and made to travel automatically along the connection direction of the connection portion 10a, thereby forming the first upper belt-shaped sheet welded portion 19.

[0056] 3, in a process prior to the first welding step, the underside of the widthwise end of the protective sheet 4C located at the bottom of one of the multilayer integrated waterproof sheets 2 (the multilayer integrated waterproof sheet 2 on the right side as you face FIG. 3) is brought into contact with the top surface of the widthwise end of the protective sheet 4C located at the bottom of the other of the multilayer integrated waterproof sheets 2 (the multilayer integrated waterproof sheet 2 on the left side as you face FIG. 3), and they are welded together using a manual pressure welding machine 29, thereby forming a bottom edge protective mat welded area 24. Meanwhile, in a process subsequent to the fifth welding step, the underside of the widthwise end of the protective sheet 4A located at the top of one of the multilayer integrated waterproof sheets 2 is brought into contact with the top surface of the widthwise end of the protective sheet 4A located at the top of the other of the multilayer integrated waterproof sheets 2, and they are welded together using a manual pressure welding machine 29, thereby forming a top edge protective mat welded area 18.

[0057] In the waterproof structure 1a according to the first embodiment, as described above, five welding areas form welding lines: second lower belt-shaped sheet welding area 22 formed in the first welding step, lower waterproof sheet welding area 23 formed in the second welding step, second upper belt-shaped sheet welding area 20 formed in the third welding step, first lower belt-shaped sheet welding area 21 formed in the fourth welding step, and first upper belt-shaped sheet welding area 19 formed in the fifth welding step. Furthermore, three areas form inspection lines for inspecting the welding quality: first upper belt-shaped sheet welding area 19 formed in the fifth welding step, second upper belt-shaped sheet welding area 20 formed in the third welding step, and lower waterproof sheet welding area 23 formed in the second welding step.

[0058] 3 and 9, at the connection portion 10a, a hook member 50 is connected by welding to the upper surface of the widthwise end portion of the waterproof sheet 5A located above one of the multilayer integrated waterproof sheets 2 at the first upper belt-shaped sheet welding portion 19. The hook member 50 is made of the same material as the waterproof sheets 5A, 5B, and is firmly welded to the upper surface of the widthwise end portion of the waterproof sheet 5A located above one of the multilayer integrated waterproof sheets 2. As shown in FIG. 1, a plurality of hook members 50 are welded at intervals along the connection direction (longitudinal direction) at the connection portion 10a. In this embodiment, the hook members 50 are provided at intervals of approximately 2.0 m or approximately 1.0 m. A manual pressure welding machine 29 is used to weld the hook member 50 to the widthwise end portion of the waterproof sheet 5A located above one of the multilayer integrated waterproof sheets 2.

[0059] 3 and 9, openings 51 are formed in the upper end protection mat welding area 18 in the connection area 10a at positions corresponding to the hook members 50. Each hook member 50 welded to the upper surface of the waterproof sheet 5A in the first upper belt-shaped sheet welding area 19 is inserted into the corresponding opening 51 provided in the upper end protection mat welding area 18 and protrudes upward. Floating devices (not shown) are attached to these hook members 50, respectively.

[0060] At the connection portion 10a of each multilayer integrated waterproof sheet 2, 2, five locations - the first upper belt sheet welding portion 19, the second upper belt sheet welding portion 20, the first lower belt sheet welding portion 21, the second lower belt sheet welding portion 22, and the lower waterproof sheet welding portion 23 - are firmly welded by an automatic up-and-down pressure welding machine 27. As a result, in this waterproof structure 1a, the widthwise ends of the waterproof sheets 5A, 5B of adjacent multilayer integrated waterproof sheets 2, 2 are firmly connected together at the connection portion 10a by the upper belt sheet 13 and the lower belt sheet 14. This welding strength is much greater than the welding strength due to the partial welding portions (indicated by the dash-dotted lines in Figure 1 ) applied when the sheets are integrated into the multilayer integrated waterproof sheet 2.

[0061] After the waterproof structure 1a according to the first embodiment described above is pulled out above the sea surface, it is temporarily kept afloat on the sea surface by the floating devices until it is sunk. At this time, the floating devices provide sufficient buoyancy for the protective mats 4A, 4A on the first layer (top) of each multilayer integrated waterproof sheet 2 of the waterproof structure 1a and the waterproof sheet 5A on the second layer (upper side) of one of the multilayer integrated waterproof sheets 2 to float on the sea surface. In the waterproof structure 1a, the multilayer integrated waterproof sheets 2, 2 are firmly welded at five welding sites (five welding lines) at the connection sites 10a at which the first upper belt-shaped sheet welds 19, the second upper belt-shaped sheet welds 20, the first lower belt-shaped sheet welds 21, the second lower belt-shaped sheet welds 22, and the lower waterproof sheet welds 23.

[0062] As a result, even if the waterproof structure 1a is temporarily moored on the sea surface for a long period of time and is subjected to the effects of wind and waves, the risk of the third layer (middle) protective mat 4B, the fourth layer (lower) waterproof sheet 5B, and the fifth layer (lower end) protective mat 4C of each multi-layer integrated waterproof sheet 2 in the waterproof structure 1a falling off can be reduced, and the original multi-layer structure can be maintained.

[0063] Furthermore, in the waterproof structure 1a of the first embodiment, at the connection portions 10a of each multi-layer integrated waterproof sheet 2, 2, the welding is performed in the following order: lower end protective mat welding portion 24 → second lower strip sheet welding portion 22 (first welding step) → lower waterproof sheet welding portion 23 (second welding step) → second upper strip sheet welding portion 20 (third welding step) → first lower strip sheet welding portion 21 (fourth welding step) → first upper strip sheet welding portion 19 (fifth welding step) → upper end protective mat welding portion 18.

[0064] In the first to fifth welding steps, the automatic up-and-down pressure welding machine 27, which provides the greatest welding strength when the welding temperature and welding time per unit area are the same, can be used without any problems. This allows the waterproof sheets 5A, 5B located above and below each of the multilayer integrated waterproof sheets 2, 2 to be firmly connected at the connection site 10a, and also shortens the operation time.

[0065] Next, a waterproof structure 1b according to a second embodiment will be described with reference to Figures 10 and 11. When describing the waterproof structure 1b according to the second embodiment, only the differences from the waterproof structure 1a according to the first embodiment will be described as appropriate. In the waterproof structure 1b according to the second embodiment, the widthwise end of one multilayer integrated waterproof sheet 2 and the widthwise end of the other multilayer integrated waterproof sheet 2 are connected by a connection portion 10b. Referring to FIG. 10, the connection portion 10b is configured, in particular, so as to be connected as follows. That is, the widthwise end portions of the upper waterproof sheets 5A, 5A located in the second layer (upper side) of each multilayer integrated waterproof sheet 2, 2 are overlapped and connected. The lower waterproof sheet 5B located in the fourth layer (lower side) of one multilayer integrated waterproof sheet 2 (the multilayer integrated waterproof sheet 2 on the right side as you face FIG. 10) is connected to the upper waterproof sheet 5A located in the second layer (upper side) of the other multilayer integrated waterproof sheet 2 (the multilayer integrated waterproof sheet 2 on the left side as you face FIG. 10) via a strip-shaped sheet 53. The widthwise end portions of the lower waterproof sheets 5B, 5B located in the fourth layer (lower side) of each multilayer integrated waterproof sheet 2, 2 are overlapped and connected.

[0066] The strip-shaped sheet 53 is made of the same material as the waterproof sheets 5A and 5B. As shown in FIG. 11(a), the strip-shaped sheet 53 is formed in a long strip shape along the connection direction of the connection parts 10b. Alternatively, as shown in FIG. 11(b), the strip-shaped sheet 53 may be formed in a long strip shape along a direction perpendicular to the connection direction of the connection parts 10b, and multiple strip-shaped sheets 53 may be arranged at intervals along the connection direction of the connection parts 10b. In this embodiment, multiple strip-shaped sheets 53 are arranged with the necessary strength to prevent the third protective mat, the fourth waterproof sheet, and the fifth protective mat from peeling off and falling off. Therefore, the welding length is shorter than in the embodiment shown in FIG. 11(a), and as a result, the time required for the welding operation can be shortened.

[0067] The connection portion 10b will be described in detail below. The connection portion 10b comprises an upper end protective mat welding portion 18 where the widthwise ends of the protective mats 4A, 4A located on the first layer (upper end) of each multilayer integrated waterproof sheet 2, 2 are overlapped and welded, an upper waterproof sheet welding portion 56 where the widthwise ends of the upper waterproof sheets 5A, 5A located on the second layer (upper side) of each multilayer integrated waterproof sheet 2, 2 are overlapped and welded, and a first strip-shaped sheet welding portion 57 where the other widthwise end of the strip-shaped sheet 53 and a portion slightly inward from the widthwise end of the upper waterproof sheet 5A located on the second layer (upper side) of the other multilayer integrated waterproof sheet 2 are overlapped and welded. It is composed of a second strip-shaped sheet welding area 58 where one widthwise end of the strip-shaped sheet 53 and an area slightly inward from the widthwise end of the lower waterproof sheet 5B located on the fourth layer (lower side) of one of the multi-layer integrated waterproof sheets 2 are overlapped and welded together, a lower waterproof sheet welding area 59 where the widthwise ends of the lower waterproof sheets 5B, 5B located on the fourth layer (lower side) of each multi-layer integrated waterproof sheet 2, 2 are overlapped and welded together, and a lower end protective mat welding area 24 where the widthwise ends of the protective mats 4A, 4A located on the fifth layer (lower end) of each multi-layer integrated waterproof sheet 2, 2 are overlapped and welded together.

[0068] In the waterproof structure 1b according to the second embodiment, as described above, four welding areas at the connection portion 10b form welding lines: lower waterproof sheet welding area 59, second strip-shaped sheet welding area 58, first strip-shaped sheet welding area 57, and upper waterproof sheet welding area 56. In addition, two areas, lower waterproof sheet welding area 59 and upper waterproof sheet welding area 56, form inspection lines for inspecting the welding quality.

[0069] Next, a manufacturing method of a waterproof structure 1b according to the second embodiment, i.e., an installation method (connection method) according to the first embodiment at the connection portion 10b of each multilayer integrated waterproof sheet 2, 2, will be described based on Fig. 12, with appropriate reference to Figs. 6 to 8. Note that the protective mats 4A, 4B, and 4C are not shown in Fig. 12. The connection portion 10b is welded in the following order: lower end protective mat welding portion 24 shown in Fig. 10 → second strip-shaped sheet welding portion 58 (first welding step) → lower waterproof sheet welding portion 59 (second welding step) → first strip-shaped sheet welding portion 57 (third welding step) → upper waterproof sheet welding portion 56 (fourth welding step) → upper end protective mat welding portion 18 shown in Fig. 10.

[0070] That is, first, as shown in Figure 12(a), in the first welding step, the underside of one widthwise end of the strip-shaped sheet 53 is brought into contact with the upper surface of a portion slightly inward from the widthwise end of the waterproof sheet 5B located below one of the multi-layer integrated waterproof sheets 2, and welded together using an automatic upper and lower pressure welding machine 28 to form a second strip-shaped sheet welding portion 58.

[0071] Specifically, in the first welding step, the band-shaped sheet 53 is lifted together with the waterproof sheet 5B located below one of the multilayer integrated waterproof sheets 2 so that the arms 36 and main body 37 of the automatic vertical pressure welding machine 27 do not interfere with the widthwise end of the waterproof sheet 5B of one of the multilayer integrated waterproof sheets 2 and the strip-shaped sheet 53, and the lower pressure roller 33 of the automatic vertical pressure welding machine 27 is inserted below the waterproof sheet 5B located below one of the multilayer integrated waterproof sheets 2 so as to abut against the underside of the widthwise end of the waterproof sheet 5B. Also, the upper pressure roller 32 of the automatic vertical pressure welding machine 27 is positioned so as to abut against the upper surface of one widthwise end of the strip-shaped sheet 53. Furthermore, the hot air supply pipe 35 of the automatic vertical pressure welding machine 27 is positioned so that its outlet 34 is located between the waterproof sheet 5B located below one of the multilayer integrated waterproof sheets 2 and the strip-shaped sheet 53. Then, the automatic vertical pressure welding machine 27 is driven and caused to move automatically along the connecting direction of the connecting portion 10b, thereby forming the second belt-shaped sheet welding portion 58.

[0072] Next, as shown in Figure 12(b), in the second welding step, the underside of the widthwise end of the waterproof sheet 5B located below one of the multi-layer integrated waterproof sheets 2 and the upper side of the widthwise end of the waterproof sheet 5B located below the other multi-layer integrated waterproof sheet 2 are brought into contact and welded together using an automatic upper and lower pressure welding machine 27 to form a lower waterproof sheet welding portion 59.

[0073] Specifically, in the second welding step, the waterproof sheets 5B, 5B located below each multi-layer integrated waterproof sheet 2, including the strip-shaped sheet 53, are lifted so that the arm 36 and main body 37 of the automatic upper and lower pressure welding machine 27 do not interfere with the waterproof sheets 5B, 5B and the strip-shaped sheet 53 of each multi-layer integrated waterproof sheet 2, and the lower pressure roller 33 of the automatic upper and lower pressure welding machine 27 is inserted below the waterproof sheet 5B located below the other multi-layer integrated waterproof sheet 2 and abutted against the underside of the widthwise end of the waterproof sheet 5B.

[0074] Furthermore, strip-shaped sheet 53 is turned up, and upper pressure roller 32 of automatic vertical pressure welding machine 27 is positioned so that it abuts against the upper surface of the widthwise end of waterproof sheet 5B located below one of the multilayer integrated waterproof sheets 2. Furthermore, hot air supply pipe 35 of automatic vertical pressure welding machine 27 is positioned so that its outlet 34 is located between waterproof sheet 5B located below one of the multilayer integrated waterproof sheets 2 and the waterproof sheet 5B located below the other multilayer integrated waterproof sheet 2. Then, automatic vertical pressure welding machine 27 is driven and made to travel automatically along the connection direction of connection portion 10b, thereby forming lower waterproof sheet welded portion 59.

[0075] Next, as shown in Figure 12(c), in the third welding step, the upper surface of the other widthwise end of the strip-shaped sheet 53 is brought into contact with the lower surface of a portion of the waterproof sheet 5A located above the other multi-layer integrated waterproof sheet 2, slightly inward from the widthwise end, and welded together using an automatic upper and lower pressure welding machine 27 to form the first strip-shaped sheet welding portion 57.

[0076] Specifically, to prevent the arms 36 and main body 37 of the automatic vertical pressure welding machine 27 from interfering with the upper waterproof sheet 5A and strip-shaped sheet 53 of the other multilayer integrated waterproof sheet 2, the waterproof sheet 5A located above the other multilayer integrated waterproof sheet 2, including the strip-shaped sheet 53, is raised, and the lower pressure roller 33 of the automatic vertical pressure welding machine 27 is inserted below the strip-shaped sheet 53 to abut against the underside of the widthwise end of the strip-shaped sheet 53. In addition, the upper pressure roller 32 of the automatic vertical pressure welding machine 27 is positioned so as to abut against the upper surface of the waterproof sheet 5A located above the other multilayer integrated waterproof sheet 2. At this time, interference with the automatic vertical pressure welding machine 27 can be prevented by, for example, turning up the widthwise end of the upper waterproof sheet 5A of the other multilayer integrated waterproof sheet 2. Furthermore, the hot air supply pipe 35 of the automatic vertical pressure welding machine 27 is positioned so that its outlet 34 is located between the waterproof sheet 5A located on the upper side of the other multilayer integrated waterproof sheet 2 and the strip-shaped sheet 53. Then, the automatic vertical pressure welding machine 27 is driven and made to run automatically along the connection direction of the connection part 10b, thereby forming the first strip-shaped sheet welding part 57.

[0077] Since the first belt-shaped sheet welding portion 57 is intended to prevent peeling, an upper pressure automatic welding machine 28 that can easily perform welding may be used (the specific welding method will be described later).

[0078] Next, as shown in Figure 12(d), in the fourth welding step, the underside of the widthwise end of the waterproof sheet 5A located on the upper side of one multi-layer integrated waterproof sheet 2 and the upper side of the widthwise end of the waterproof sheet 5A located on the upper side of the other multi-layer integrated waterproof sheet 2 are brought into contact and welded together using an automatic up and down pressure welding machine 27 to form the upper waterproof sheet welding portion 56.

[0079] Specifically, in the fourth welding step, the upper waterproof sheets 5A of each multilayer integrated waterproof sheet 2 are raised so that the arms 36 and main body 37 of the automatic vertical pressure welding machine 27 do not interfere with the waterproof sheets 5A of each multilayer integrated waterproof sheet 2, and the lower pressure roller 33 of the automatic vertical pressure welding machine 27 is inserted below the upper waterproof sheet 5A of the other multilayer integrated waterproof sheet 2 to abut against the underside of the widthwise end of that waterproof sheet 5A. Also, the upper pressure roller 32 of the automatic vertical pressure welding machine 27 is positioned so as to abut against the upper surface of the widthwise end of the waterproof sheet 5A located above one of the multilayer integrated waterproof sheets 2. Furthermore, the hot air supply pipe 35 of the automatic vertical pressure welding machine 27 is positioned so that its outlet 34 is located between the upper waterproof sheets 5A of the multilayer integrated waterproof sheets 2. Then, the automatic vertical pressure welding machine 27 is driven and caused to move automatically along the connecting direction of the connection portion 10b, thereby forming the upper waterproof sheet welding portion 56.

[0080] Next, a manufacturing method of a waterproof structure 1b according to the second embodiment, i.e., an installation method (connection method) according to the second embodiment at the connection portion 10b of each multilayer integrated waterproof sheet 2, 2, will be described based on Fig. 13, with appropriate reference to Figs. 6 to 8. Note that protective mats 4A, 4B, and 4C are not shown in Fig. 13. The connection portion 10b is welded in the following order: lower end protective mat welding portion 24 shown in Fig. 10 → lower waterproof sheet welding portion 59 (first welding step) → second strip-shaped sheet welding portion 58 (second welding step) → first strip-shaped sheet welding portion 57 (third welding step) → upper waterproof sheet welding portion 56 (fourth welding step) → upper end protective mat welding portion 18 shown in Fig. 10.

[0081] That is, as shown in Figure 13(a), in the first welding step, the lower surface of the widthwise end of the waterproof sheet 5B located on the lower side of one multi-layer integrated waterproof sheet 2 is brought into contact with the upper surface of the widthwise end of the waterproof sheet 5B located on the lower side of the other multi-layer integrated waterproof sheet 2, and welded together using an automatic up and down pressure welding machine 27 to form the lower waterproof sheet welding portion 59.

[0082] Specifically, in the first welding step, the waterproof sheets 5B, 5B located below each of the multilayer integrated waterproof sheets 2, 2 are raised so that the arms 36 and main body 37 of the automatic vertical pressure welding machine 27 do not interfere with the waterproof sheets 5B, 5B of each of the multilayer integrated waterproof sheets 2, 2, and the lower pressure roller 33 of the automatic vertical pressure welding machine 27 is inserted below the waterproof sheet 5B located below the other multilayer integrated waterproof sheet 2 to abut against the underside of the widthwise end of that waterproof sheet 5B. Also, the upper pressure roller 32 of the automatic vertical pressure welding machine 27 is positioned so as to abut against the upper surface of the widthwise end of the waterproof sheet 5B located below one of the multilayer integrated waterproof sheets 2. Furthermore, the hot air supply pipe 35 of the automatic vertical pressure welding machine 27 is positioned so that its outlet 34 is located between the waterproof sheets 5B, 5B located below the respective multilayer integrated waterproof sheets 2, 2. Then, the automatic vertical pressure welding machine 27 is driven and self-propelled along the connection direction of the connection portion 10b, thereby forming the lower waterproof sheet welding portion 59.

[0083] Next, as shown in Figure 13(b), in the second welding step, the underside of one widthwise end of the strip-shaped sheet 53 is brought into contact with the upper surface of a portion of the waterproof sheet 5B located below one of the multi-layer integrated waterproof sheets 2, slightly inward from the widthwise end, and welded together using an upper pressure automatic welding machine 28 to form a second strip-shaped sheet welding portion 58.

[0084] Specifically, in the second welding step, upper pressure roller 40 of upper pressure automatic welding machine 28 is placed on the upper surface of one widthwise end of strip-shaped sheet 53, and hot air supply pipe 42 is positioned so that its outlet 41 is located between one widthwise end of strip-shaped sheet 53 and waterproof sheet 5B located below one of the multilayer integrated waterproof sheets 2. Then, upper pressure automatic welding machine 28 is driven and made to run automatically along the connection direction of connection part 10b, thereby forming second strip-shaped sheet welded part 58.

[0085] Next, as shown in Figure 13(c), in the third welding step, the upper surface of the other widthwise end of the strip-shaped sheet 53 is brought into contact with the lower surface of a portion of the waterproof sheet 5A located above the other multi-layer integrated waterproof sheet 2, slightly inward from the widthwise end, and welded together using an upper pressure automatic welding machine 28 to form the first strip-shaped sheet welding portion 57.

[0086] Specifically, the upper pressure roller 40 of the upper pressure automatic welding machine 28 is positioned so as to abut against the upper surface of the waterproof sheet 5A located above the other multilayer integrated waterproof sheet 2. Furthermore, the widthwise end of the waterproof sheet 5A located above the other multilayer integrated waterproof sheet 2 is turned up slightly toward the upper pressure automatic welding machine 28, and the hot air supply pipe 42 of the upper pressure automatic welding machine 28 is positioned so that its outlet 41 is located between the other widthwise end of the strip sheet 53 and the waterproof sheet 5A located above the other multilayer integrated waterproof sheet 2. The upper pressure automatic welding machine 28 is then driven and caused to move freely along the connection direction of the connection part 10b, thereby forming the first strip-shaped sheet welded part 57. In this third welding step, an upper press automatic welding machine 28 is used, but it is also possible to use an upper and lower press automatic welding machine 27 as in the third welding step of the construction method according to the first embodiment (FIG. 12(c)) and perform welding as described above.

[0087] In addition, the fourth welding step (Figure 13(d)) of the construction method according to the second embodiment at the connection portion 10b of the waterproof structure 1b according to the second embodiment is the same as the fourth welding step (Figure 12(d)) of the construction method according to the first embodiment, and has been described above, so its explanation will be omitted here.

[0088] In this embodiment, as shown in Figure 11(a), the strip-shaped sheet 53 is formed in a long strip shape along the connection direction of the connection parts 10b, and the upper press automatic welding machine 28 is used in the second welding step and the third welding step (Figures 13(b) and (c)) in the construction method according to the second embodiment. However, when the strip-shaped sheet 53 is formed in a long strip shape along a direction perpendicular to the connection direction of the connection parts 10b as shown in Figure 11(b), and a plurality of the strip-shaped sheets 53 are arranged at intervals along the connection direction of the connection parts 10b, a manual press welding machine 29 may be used as long as the welding strength can be ensured. When using this manual press welding machine 29, the worker holds the grip part 45 and presses the tip of the hot air supply pipe 44 against the top surface of the strip-shaped sheet 53 and the other waterproof sheet 5A, and proceeds while supplying hot air to perform welding, making construction easy.

[0089] In the waterproof structure 1b of the second embodiment described above, the connection portion 10b is provided with only a strip-shaped sheet 53 (see Figure 10), so the manufacturing costs of the sheet material can be reduced compared to the connection portion 10a of the waterproof structure 1a of the first embodiment (which is provided with an upper strip-shaped sheet 13 and a lower strip-shaped sheet 14 shown in Figure 3).

[0090] Furthermore, in the waterproof structure 1b according to the second embodiment, four welding sites at the connection portion 10b - lower waterproof sheet welding site 59, second strip-shaped sheet welding site 58, first strip-shaped sheet welding site 57, and upper waterproof sheet welding site 56 - serve as welding lines, and two welding sites - lower waterproof sheet welding site 59 and upper waterproof sheet welding site 56 - serve as inspection lines for inspecting the welding quality. As a result, compared to the connection portion 10a of the waterproof structure 1a according to the first embodiment, one welding line and one inspection line are both reduced. As a result, in the waterproof structure 1b according to the second embodiment, the connection strength at the connection portions 10b of the multilayer integrated waterproof sheets 2, 2 is ensured, and the welding work time can be shortened compared to the connection portion 10a of the waterproof structure 1a according to the first embodiment, which ultimately leads to a reduction in construction costs.

[0091] Furthermore, in the construction methods of the first and second embodiments at the connection portion 10b of the waterproof structure 1b of the second embodiment, the first to fourth welding steps can be carried out sequentially without any problems using the upper and lower pressure automatic welding machine 27 and the upper pressure automatic welding machine 28 (manual pressure welding machine 29), so that the connection strength of the waterproof sheets 5A, 5B located on the upper and lower sides of each multi-layer integrated waterproof sheet 2 can be ensured while the time required for the welding work can be shortened. [Explanation of symbols]

[0092] 1a, 1b Water-impermeable structure, 2 Multilayer integrated water-impermeable sheet, 4A, 4B, 4C Protective mat, 5A, 5B Water-impermeable sheet, 10a, 10b Connection portion, 13 Upper belt-shaped sheet, 14 Lower belt-shaped sheet, 19 First upper belt-shaped sheet welding portion, 20 Second upper belt-shaped sheet welding portion, 21 First lower belt-shaped sheet welding portion, 22 Second lower belt-shaped sheet welding portion, 23 Lower water-impermeable sheet welding portion, 53 Belt sheet, 56 Upper water-impermeable sheet welding portion, 57 First belt-shaped sheet welding portion, 58 Second belt-shaped sheet welding portion, 59 Lower water-impermeable sheet welding portion

Claims

1. A waterproof structure in which protective mats and waterproof sheets made of different materials are alternately stacked and partially welded together to connect the widthwise ends of a multi-layer integrated waterproof sheet consisting of three layers of protective mats and two layers of waterproof sheets, thereby ensuring a desired sheet area, The connection portion between the width direction end of one multilayer integrated waterproof sheet and the width direction end of the other multilayer integrated waterproof sheet is The waterproof sheets located on the upper side of each of the multilayer integrated waterproof sheets are connected via upper belt-shaped sheets made of the same material as the waterproof sheets, The waterproof sheet located below one of the multilayer integrated waterproof sheets and the waterproof sheet located above the other multilayer integrated waterproof sheet are connected via a lower belt-shaped sheet made of the same material as the waterproof sheets, A waterproof structure characterized in that the widthwise ends of the waterproof sheets located below each of the multi-layer integrated waterproof sheets are overlapped and connected.

2. The waterproof structure according to claim 1, wherein at least the upper belt-like sheet of the upper belt-like sheet and the lower belt-like sheet is formed in a long belt shape along the connection direction of the connection portion.

3. A method for manufacturing a waterproof structure in which protective mats and waterproof sheets made of different materials are alternately stacked and partially welded together to connect the widthwise ends of a multi-layer integrated waterproof sheet consisting of three layers of protective mats and two layers of waterproof sheets, thereby ensuring a desired sheet area, When connecting the widthwise end of one of the multilayer integrated waterproof sheets to the widthwise end of the other multilayer integrated waterproof sheet via an upper belt-like sheet and a lower belt-like sheet made of the same material as the waterproof sheets, a first welding step of welding the overlapping portion of the lower belt-shaped sheet and the waterproof sheet located below one of the multilayer integrated waterproof sheets; a second welding step of welding overlapping portions of widthwise ends of the waterproof sheets located below each of the multilayer integrated waterproof sheets; a third welding step of welding the overlapping portion of the upper belt-shaped sheet and the waterproof sheet located above the other multilayer integrated waterproof sheet; a fourth welding step of welding the overlapping portion of the lower belt-like sheet and the waterproof sheet located above the other multilayer integrated waterproof sheet; a fifth welding step of welding the overlapping portion of the upper belt-shaped sheet and the waterproof sheet located above one of the multilayer integrated waterproof sheets; A method for manufacturing a waterproof structure, characterized by carrying out the above steps in this order.

4. A waterproof structure in which protective mats and waterproof sheets made of different materials are alternately stacked and partially welded together to connect the widthwise ends of a multi-layer integrated waterproof sheet consisting of three layers of protective mats and two layers of waterproof sheets, thereby ensuring a desired sheet area, The connection portion between the width direction end of one multilayer integrated waterproof sheet and the width direction end of the other multilayer integrated waterproof sheet is The widthwise ends of the waterproof sheets located on the upper side of each of the multilayer integrated waterproof sheets are overlapped and connected, The waterproof sheet located below one of the multilayer integrated waterproof sheets and the waterproof sheet located above the other multilayer integrated waterproof sheet are connected via a strip-shaped sheet made of the same material as the waterproof sheets, A waterproof structure characterized in that the widthwise ends of the waterproof sheets located below each of the multi-layer integrated waterproof sheets are overlapped and connected.

5. the strip-shaped sheet is formed in a long strip shape along a direction perpendicular to the connection direction of the connection portion, The waterproof structure according to claim 4, wherein a plurality of the belt-shaped sheets are arranged at intervals along the connecting direction.

6. A method for manufacturing a waterproof structure in which protective mats and waterproof sheets made of different materials are alternately stacked and partially welded together to connect the widthwise ends of a multi-layer integrated waterproof sheet consisting of three layers of protective mats and two layers of waterproof sheets, thereby ensuring a desired sheet area, When connecting the widthwise end of one of the multilayer integrated waterproof sheets to the widthwise end of the other multilayer integrated waterproof sheet via a strip-shaped sheet made of the same material as the waterproof sheets, a first welding step of welding an overlapping portion of the waterproof sheet located below one of the multilayer integrated waterproof sheets and the belt-shaped sheet; a second welding step of welding overlapping portions of widthwise ends of the waterproof sheets located below each of the multilayer integrated waterproof sheets; a third welding step of welding the overlapping portion of the strip-shaped sheet and the waterproof sheet located above the other multilayer integrated waterproof sheet; a fourth welding step of welding overlapping portions of widthwise ends of the waterproof sheets located on the upper side of each of the multilayer integrated waterproof sheets; A method for manufacturing a waterproof structure, characterized by carrying out the above steps in this order.

7. A method for manufacturing a waterproof structure in which protective mats and waterproof sheets made of different materials are alternately stacked and partially welded together to connect the widthwise ends of a multi-layer integrated waterproof sheet consisting of three layers of protective mats and two layers of waterproof sheets, thereby ensuring a desired sheet area, When connecting the widthwise end of one of the multilayer integrated waterproof sheets to the widthwise end of the other multilayer integrated waterproof sheet via a strip-shaped sheet made of the same material as the waterproof sheets, a first welding step of welding overlapping portions of widthwise ends of the waterproof sheets located below each of the multilayer integrated waterproof sheets; a second welding step of welding the overlapping portion of the waterproof sheet located below one of the multilayer integrated waterproof sheets and the belt-shaped sheet; a third welding step of welding the overlapping portion of the strip-shaped sheet and the waterproof sheet located above the other multilayer integrated waterproof sheet; a fourth welding step of welding overlapping portions of widthwise ends of the waterproof sheets located on the upper side of each of the multilayer integrated waterproof sheets; A method for manufacturing a waterproof structure, characterized by carrying out the above steps in this order.

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