Submerged installation method of tubular member and close-fitting lid for tubular member

Abstract

To make a tubular member quickly submerged which should be installed at a water bottom.SOLUTION: A water injection hole is formed at least at one tubular member out of a plurality of tubular members (S10), the plurality of tubular members are floated on water by a floating force of air which exists in the tubular members (S20, S30), close-fitting lids having exhaust ports are attached to end parts of the tubular members located at one-side ends of the plurality of tubular members at sides to which the adjacent tubular member are not connected (S40), the tubular member having the water injection hole is brought into a water injectable state from the water injection hole (S50), and pressure reduction means for decompressing the inside of the plurality of tubular members are operably attached to the exhaust ports (S40, S60). By this constitution, the water injection from the water injection hole into the tubular member can be promoted, and a speed of the water injection can be remarkably accelerated compared with a conventional method which has used atmospheric pressure and hydraulic pressure. The plurality of tubular members can be thereby quickly and efficiently submerged.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for sinking a plurality of connected tubular members on the bottom of water, and a sealing cover for the tubular members used in the method. [Background technology]

[0002] For example, in pump dredging work, sediment sucked up from the bottom of the water by a pump dredger is transported to the sand discharge area through multiple connected sand discharge pipes. In this case, the sand discharge pipe installed between the pump dredger and the sand discharge area may have an above-water part floating on the water and a bottom part sunk to the bottom of the water depending on the distance and the water area where it is installed, and the bottom part of the pipe is installed in a water area used for general ship routes, etc. (For example, see Patent Document 1). From the viewpoint of early opening of the route and safety, it is required that such a bottom sand discharge pipe be sunk to the bottom of the water as soon as possible. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-200925 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional installation of sand flushing pipes, the air inside the pipes is removed by operating an on-off valve such as a ball valve, using natural atmospheric pressure or water pressure, so the sinking speed of the sand flushing pipes is slow. In addition, since it depends on the natural environment such as atmospheric pressure and water pressure, the work time varies, making it difficult to perform the installation work stably. This type of installation work is not limited to sand flushing pipes used for transporting soil and sand, but is applicable to all tubular members through which any medium is transported, such as undersea pipelines used in infrastructure-related fields. The present invention has been made in consideration of the above problems, and an object of the present invention is to quickly sink a tubular member to be installed on the bottom of water. [Means for solving the problem]

[0005] (Modes of the Invention) The following aspects of the invention are illustrative of the configuration of the present invention, and are described in terms of items to facilitate understanding of the various configurations of the present invention. Each item does not limit the technical scope of the present invention, and the technical scope of the present invention may include any embodiment in which some of the components of each item are replaced or deleted, or other components are added, while taking into account the best mode for carrying out the invention.

[0006] (1) A method for sinking a number of connected tubular members to the bottom of the water, comprising the steps of providing a water inlet hole in at least one of the tubular members, floating the tubular members on the water by the buoyancy of the air inside the tubular members, attaching a sealing lid having an exhaust port to an end of a tubular member located at one end of the tubular members on the side to which an adjacent tubular member is not connected, making the at least one tubular member capable of pouring water through the water inlet hole, and attaching and operating a pressure reducing means for reducing the pressure inside the tubular members to the exhaust port.

[0007] The method for sinking a tubular member described in this section involves sinking a plurality of tubular members that are connected and communicate with each other on the bottom of the water, and a water injection hole is provided in advance, for example, on the outer periphery of at least one of the plurality of tubular members to be sinked. The plurality of tubular members are then floated on the water at the intended sinking position, and the buoyancy of the air that exists inside the plurality of tubular members because they have been moved from land or the like is utilized to float them, and the water injection hole is closed by some means. Furthermore, a sealing lid having an exhaust port is attached to the end of the tubular member located at one end of the plurality of connected tubular members, on the side to which the adjacent tubular member is not connected. As a result, one end side of the plurality of connected tubular members is closed by the sealing lid having an exhaust port.

[0008] In addition, the tubular member with the water injection hole is opened so that the water injection hole is submerged in water, thereby enabling water to be injected from the water injection hole. Then, a pressure reducing means for reducing the pressure inside the tubular members is attached to an exhaust port provided on the sealing lid of the tubular member located at one end and operated. Then, the pressure inside the tubular members is reduced, which encourages water to be injected from the water injection hole into the tubular members, and the tubular member between the tubular member with the water injection hole and the tubular member at one end to which the pressure reducing means is attached sinks to the bottom of the water. At this time, the speed at which water is injected into the tubular members is significantly faster than in conventional methods that use atmospheric pressure or water pressure, and as a result, the tubular members are quickly and efficiently sunk, and the sunk work of the tubular members is performed stably. As a result, a route for general ships can be opened early above the sunk tubular members, and safety is ensured earlier.

[0009] (2) In the above (1), a method for submerging a tubular member is provided, in which an air ejector including a cylindrical main body and an injection portion for injecting compressed air supplied from a compressor toward one opening of the cylindrical main body inside the cylindrical main body is attached as the pressure reducing means in a manner that connects the other opening of the cylindrical main body to the exhaust port. The method for submerging a tubular member described in this section utilizes an air ejector as a pressure reducing means attached to an exhaust port of a sealing lid attached to a tubular member located at one end. This air ejector includes a cylindrical body and an ejection part, and the ejection part ejects compressed air supplied from a compressor toward one opening of the cylindrical body having openings at both ends inside the cylindrical body.

[0010] The air ejector having such a structure is attached in such a manner that the other opening on the opposite side to the one opening of the cylindrical body is connected to the exhaust port. As a result, when the air ejector is operated, a vacuum state is generated inside the cylindrical body by the action of compressed air injected by the injection part toward one opening of the cylindrical body. Then, the air in the connected multiple tubular members is sucked into the inside of the cylindrical body where a vacuum state is generated through the other opening of the cylindrical body connected to the exhaust port of the sealing lid, and is discharged as it is from the one opening of the cylindrical body. Therefore, the air in the multiple tubular members is forcibly and forcefully discharged through the air ejector, and the multiple tubular members are quickly and efficiently submerged.

[0011] (3) A method for sinking a tubular member as described above in paragraphs (1) and (2), in which the tubular member located at one end is floated on the water by a floater and a sinking operation is performed, and then the sealing lid and the pressure reducing means are removed from the tubular member located at one end, new tubular members are connected to the tubular member located at one end, and the new tubular members are repeatedly sinking together with the tubular member located at one end. In the method for sinking a tubular member described in this section, the tubular member located at one end of the multiple connected tubular members is floated on the water by a floater during the sinking operation. After that, when the operation has progressed to the extent that the tubular member connected to the tubular member located at the one end sinks, the sealing lid and the pressure reducing means are removed from the tubular member located at the one end, and new multiple tubular members to be sinking next are connected to the end of the tubular member to which the sealing lid was attached. As a result, the tubular member moves from a state where it was located at one end to a state where it is located between the multiple tubular members that have already sunk and the new multiple tubular members.

[0012] Then, after removing the floater from the tubular member located at one end to make it ready for sinking, the sinking operation is performed again on the tubular member located at the one end and the new tubular members connected thereto. At this time, among the new tubular members, the tubular member opposite the end connected to the tubular member located at one end of the tubular members that were the sinking target in the previous sinking operation is set as the new tubular member located at the one end, and is attached with a sealing lid and a pressure reducing means and floated on the water by a floater. By repeatedly performing such sinking operation, the length of the tubular member to be sunk is gradually extended as a unit for sinking the multiple tubular members connected at each sinking operation, and the tubular members over a long distance are efficiently sunk. Furthermore, by floating the tubular member located at one end with a floater, the operation of attaching the sealing lid and pressure reducing means and the operation of removing the sealing lid and pressure reducing means and connecting the next multiple tubular members are also efficiently performed.

[0013] (4) A method for submerging a tubular member according to the above items (1) and (2), wherein the plurality of tubular members are sand discharge pipes used in pump dredging work. The method for sinking a tubular member described in this section sinks sand discharge pipes used in pump dredging work as the multiple tubular members to be sinked. Here, pump dredging work is carried out, for example, for the development of a seaway or an anchorage, and is therefore inevitably carried out in a water area with relatively heavy traffic of general ships. For this reason, as mentioned in the above sections (1) and (2), by quickly and efficiently sinking the multiple sand discharge pipes used in pump dredging work, a seaway can be opened early in a water area with relatively heavy traffic of general ships, and the obstruction of ship traffic for a long period of time can be prevented. Furthermore, depending on the length of the multiple sand discharge pipes to be sinked, a contribution can be made to shorten the entire process of the pump dredging work.

[0014] (5) A sealing lid for tubular members used when sinking a plurality of connected tubular members to the bottom of water, comprising: a lid portion attached to cover an end of a tubular member located at one end of the plurality of tubular members on the side to which an adjacent tubular member is not connected; an exhaust port provided in the lid portion; and an air ejector connected to the exhaust port, the air ejector comprising: a cylindrical main body; and an injection portion that injects compressed air supplied from a compressor toward one opening of the cylindrical main body inside the cylindrical main body, the other opening of the cylindrical main body being connected to the exhaust port. The sealing cover for a tubular member described in this paragraph achieves an effect equivalent to that of the method for sinking a tubular member described in (2) above, when used in the method for sinking a tubular member described in (2) above. Effect of the Invention

[0015] Since the present invention has the above-mentioned configuration, it is possible to quickly sink the tubular member to be installed on the bottom of the water. [Brief description of the drawings]

[0016] [Figure 1] 1A and 1B are schematic diagrams showing an example of the configuration of a sealing cover for a tubular member according to an embodiment of the present invention, in which (a) is a side image diagram of the state in which it is attached to a tubular member, and (b) is a cross-sectional image diagram of an air ejector. [Diagram 2] FIG. 2 is a flow chart showing an example of a procedure for a tubular member sinking method according to an embodiment of the present invention. [Diagram 3] 1A and 1B show a state in which a tubular member is submerged by a tubular member submerging method according to an embodiment of the present invention, in which (a) is a side image diagram of multiple tubular members, and (b) is an image diagram of the operation around an air ejector. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings. Here, detailed descriptions of the same or corresponding parts as those in the prior art will be omitted, and the same or corresponding parts are indicated by the same reference numerals throughout the drawings. Fig. 1 shows a schematic diagram of an example of the configuration of a sealing cover 10 for tubular members according to an embodiment of the present invention, which is used when sinking a plurality of tubular members 40 (see Fig. 3(a)) to the water bottom BW as described below. In the following explanation, unless otherwise specified, the case will be explained in which the plurality of tubular members 40 to be sinked are sand discharge pipes 40 used in pump dredging work.

[0018] As shown in Fig. 1(a), a sealing lid 10 for a tubular member according to an embodiment of the present invention includes a lid portion 12, an exhaust port 14, and a pressure reducing means 20. The lid portion 12 is attached to an end portion 42 of a tubular member 40 (40A) located at one end (the left end in Fig. 3(a)) of a plurality of tubular members (sand discharge pipes) 40 connected as shown in Fig. 3(a), on the side where the adjacent tubular members 40 are not connected. That is, such an end portion 42 is in an open state because the tubular members 40 are not connected, and the lid portion 12 is attached so as to close the open end portion 42. For this reason, the lid portion 12 has a shape and size corresponding to the shape and size of the end portion 42 of the tubular member 40A.

[0019] As described above, the exhaust port 14 is provided in the lid portion 12 attached to the end portion 42 of the tubular member 40A, and communicates the inside of the tubular member 40 with the outside. The decompression means 20 is connected to the exhaust port 14, and the decompression means 20 is for decompressing the inside of the connected tubular members 40. In this embodiment, an air ejector 20A is used as the decompression means 20. Referring also to FIG. 1(b), the air ejector 20A includes a cylindrical body 22 and an ejection portion 26. The cylindrical body 22 is substantially cylindrical and has two openings 22a and 22b on both sides that communicate with the inside 22c. The other opening 22b of the cylindrical body 22 is connected to the exhaust port 14 so that one opening 22a of the cylindrical body 22 is opened and the other opening 22b communicates with the inside of the tubular member 40A via the exhaust port 14 of the lid portion 12.

[0020] The jet unit 26 is for jetting compressed air toward one opening 22a of the cylindrical main body 22 in the inside 22c of the cylindrical main body 22. For that purpose, the jet unit 26 has an appropriate configuration for realizing jetting toward one opening 22a, and is connected to a compressor 30 for supplying compressed air via a hose 32. More specifically, the jet unit 26 has an jet port 26a and a supply port 26b, and the jet port 26a is directed toward one opening 22a of the cylindrical main body 22, and the hose 32 is connected to the supply port 26b, which communicates with the outside, via an appropriate connector (not shown).

[0021] Next, with reference to the flow diagram shown in FIG. 2, a specific procedure of the method for sinking a tubular member according to the embodiment of the present invention, which is carried out using the above-mentioned sealing lid 10 for a tubular member, will be described. For the configuration of the sealing lid 10 for a tubular member, please refer to FIG. 1 as appropriate. Note that the flow diagram shown in FIG. 2 shows an example for explaining the specific procedure. Therefore, the procedure of the method for sinking a tubular member according to the embodiment of the present invention is not limited to the flow diagram of FIG. 2, and may be a flow in which some of the steps shown in FIG. 2 are deleted, changed, or appropriately added depending on, for example, the configuration of the tubular member 40 to be sinked and the environment of the water area where the sinking work is performed.

[0022] S10 (connecting tubular members and preparing water injection holes): Connect multiple tubular members (sand discharge pipes) 40 to be submerged. More specifically, the tubular members 40 may be connected to the quay of a port or the like for the length to be submerged, and all the tubular members 40 to be submerged at once may be connected. Alternatively, multiple tubular members 40 connected to a certain length may be prepared and connected before submersion, taking into consideration transportation to the submersion site, etc. Although not limited to this, for example, in the case of sand discharge pipes 40, one sand discharge pipe 40 with a length of about 6 m may be connected to a length of about 200 m to be submerged at one time. In addition, the connection points that are expected to be bent during the submersion work described later may be connected via a rubber joint (sleeve) 52 as shown in FIG. 3(a), for example. Furthermore, as shown in Figure 3(a), it is preferable that a water injection hole 46 is provided in advance in at least one of the tubular members 40 (40B) to be connected, and that the tubular member 40B in which this water injection hole 46 is provided is located near one end of the multiple tubular members 40 to be submerged (near the right end in Figure 3(a)).

[0023] S20 (floating on water): The multiple connected tubular members 40 are lowered from the quay or the like where the connecting work was performed in S10 above onto the water OW (see FIG. 3(a)) and floated. At this time, the floaters 50 (see FIG. 3(a)) or the like are used to float them, and the water injection holes 46 provided in the tubular members 40B are closed by some means. S30 (towing to installation site): The multiple tubular members 40 floating on the surface OW are towed to above the installation site by a work boat or the like. Then, the multiple tubular members 40 are lowered from the floater 50, and are brought into a floating state on the surface OW above the installation site by utilizing the buoyancy of the air present in the multiple tubular members 40. At this time, in this embodiment, as shown in FIG. 3(a), the tubular member 40A located at one end (the left end in FIG. 3(a)) of the multiple connected tubular members 40 is kept floating on the surface OW by the floater 50.

[0024] S40 (attachment of sealing lid and pressure reducing means): The sealing lid 10 for the tubular member is attached to the end 42 of the tubular member 40A located at one end, which is not connected to the adjacent tubular member 40, while the tubular member 40A is floating on the water OW by the floater 50. The air ejector 20A as the pressure reducing means 20 is attached to the exhaust port 14 of this sealing lid 10 for the tubular member, as shown in FIG. 1. For this reason, the compressor 30 is connected to the air ejector 20A via the hose 32. Note that, during the connection work of the tubular member 40 in the above S10, the sealing lid 10 for the tubular member and the pressure reducing means 20 may be attached in advance to the tubular member 40A located at one end. S50 (start of water injection): As shown in FIG. 3(a), the water injection hole 46 provided in at least one tubular member 40B is opened, and water is made available for injection from the water injection hole 46 into the inside of the tubular member 40B, and further into the insides of the multiple tubular members 40 connected to the tubular member 40B, and water injection is started.

[0025] S60 (operation of pressure reducing means): The pressure reducing means 20 of the sealing lid 10 for the tubular member is operated. That is, in this embodiment, the supply of compressed air from the compressor 30 to the air ejector 20A is started, and the air ejector 20A is operated. Then, as shown in FIG. 3(b), compressed air is injected from the injection port 26a of the injection part 26 toward one opening 22a of the cylindrical body 22, thereby generating a vacuum state in the interior 22c of the cylindrical body 22. Then, air in the tubular member 40A located at one end to which the sealing lid 10 for the tubular member is attached is sucked into the interior 22c of the cylindrical body 22 where the vacuum state is generated, through the other opening 22b of the cylindrical body 22 and the exhaust port 14. The sucked air is discharged to the outside as it is from one opening 22a of the cylindrical body 22, so that air is forcibly discharged from the connected multiple tubular members 40, which promotes water injection from the water injection hole 46.

[0026] S70 (sinking of tubular members): The operation of the pressure reducing means 20 in S60 above encourages water to be poured into the multiple tubular members 40 from the water injection hole 46, so that the multiple tubular members 40 sink between the tubular member 40B with the water injection hole 46 and the tubular member 40A located at one end, as shown in Fig. 3(a). This causes the multiple tubular members 40 to be sunk to the water bottom BW. S80 (determination of submerged tubular members): It is determined whether or not all of the tubular members 40 to be submerged have been submerged. For example, the tubular members 40 are submerged starting from the tubular member 40B side where the water injection hole 46 is provided, and when the tubular member 40 connected to the tubular member 40A located at one end floated by the floater 50 is submerged to a certain extent in the water, it may be determined that the tubular members 40 have been submerged. Note that the criteria for determining whether or not all of the tubular members 40 have been submerged are not limited to this, and appropriate criteria may be used depending on the situation. Then, if it is determined that all of the tubular members 40 have been submerged (YES), the process proceeds to S90, and if it is determined that they have not yet been submerged (NO), the process returns to S70 and the submerging operation continues.

[0027] S90 (repeated judgment): judge whether or not to extend the length of the tubular member 40 and continue the sinking operation, in other words, judge whether or not the multiple tubular members 40 have been sunk to the designed length. If it is judged that the sinking operation should be continued (YES) because the multiple tubular members 40 that have been sunk have not yet reached the designed length, proceed to S100. On the other hand, if it is judged that the sinking operation should not be continued (NO) because the multiple tubular members 40 have already been sunk to the designed length, the explanation of the method for sinking a tubular member ends here.

[0028] S100 (Removal of sealing lid and pressure reducing means): The sealing lid 10 for the tubular member is removed together with the pressure reducing means 20 from the tubular member 40A located at one end floated by the floater 50. S110 (Preparation of new tubular members): Prepare new tubular members 40 to be submerged next. That is, the same procedures as S10 to S30 described above are performed for the new tubular members 40. At this time, the new tubular members 40 do not need to include a tubular member 40 provided with a water injection hole 46.

[0029] S120 (connecting new tubular members): The new multiple tubular members 40 prepared in S110 above are connected to the end 42 of the tubular member 40A from which the sealing lid 10 for the tubular member was removed in S100 above. This brings the inside of the new multiple tubular members 40 into communication with the inside of the multiple tubular members 40 already submerged via the tubular member 40A. Then, the tubular member 40A that was floating by the floater 50 is lowered from the floater 50 and made ready to be submerged.

[0030] S130 (attaching the sealing lid and pressure reducing means): The tubular member 40 located at the end opposite to the end connected to the tubular member 40A in S120 is floated by the floater 50 as a new tubular member 40A located at one end. Then, the sealing lid 10 for the tubular member is attached to the end 42 of the new tubular member 40A on the side to which the adjacent tubular member 40 is not connected, together with the pressure reducing means 20. After that, the process returns to S60, and the above S60 to S80 are executed again for the new tubular members 40. At this time, the tubular member 40A lowered from the floater 50 in S120 is also sunk to the water bottom BW together with the new tubular members 40. Water is poured into the new tubular members 40 through the tubular member 40B with the water injection hole 46 that has already sunk in the water or is sunk to the water bottom BW. This sinking operation is repeated until it is determined in S90 that the multiple tubular members 40 have been sinking over the designed length.

[0031] Here, the sealing cover 10 for a tubular member according to the embodiment of the present invention and the method for sinking a tubular member according to the embodiment of the present invention are not limited to the configurations described above. For example, the decompression means 20 is not limited to the air ejector 20A as long as it reduces the pressure inside the multiple tubular members 40 through the exhaust port 14, and may be a pump that directly sucks air from inside the multiple tubular members 40. In addition, the multiple tubular members 40 to be sinked are not limited to sand discharge pipes 40, and may be any tubular member that sends a medium through its inside, such as a submarine pipeline used in infrastructure.

[0032] According to the embodiment of the present invention having the above-mentioned configuration, the following effects can be obtained. That is, the method of sinking a tubular member according to the embodiment of the present invention sinks a plurality of tubular members 40, which are connected and communicate with each other inside, on the bottom of the water BW, as shown in FIG. 3(a), for example. Specifically, a water injection hole 46 is provided in advance, for example, on the outer periphery of at least one tubular member 40B among the plurality of tubular members 40 to be sinked (see S10 in FIG. 2). Then, the plurality of tubular members 40 are floated on the water surface OW at the intended sinking position, and at this time, the buoyancy of air present inside the plurality of tubular members 40 because they have been moved from land or the like is utilized to float them, and the water injection hole 46 is closed by some means (see S20, S30 in FIG. 2).

[0033] Furthermore, a sealing lid 10 having an exhaust port 14, for example as shown in FIG. 1(a), is attached to the end 42 of the tubular member 40A located at one end of the multiple connected tubular members 40, on the side where the adjacent tubular member 40 is not connected (see S40 in FIG. 2). As a result, one end side of the multiple connected tubular members 40 is closed by the sealing lid 10 having the exhaust port 14. Also, the tubular member 40B having the water injection hole 46 is made in a state where the water injection hole 46 is immersed in water and opened, so that water can be injected from the water injection hole 46 (see S50 in FIG. 2). Then, a pressure reducing means 20 for reducing the pressure inside the multiple tubular members 40 is attached to the exhaust port 14 provided in the sealing lid 10 of the tubular member 40A located at one end and operated (see S40, S60 in FIG. 2).

[0034] Then, the pressure inside the multiple tubular members 40 is reduced, which encourages water to be poured into the tubular members 40 from the water injection holes 46, and the tubular members 40 can be submerged to the bottom BW between the tubular member 40B with the water injection holes 46 and the tubular member 40A at one end to which the pressure reducing means 20 is attached (see S70 in FIG. 2). At this time, the speed at which water is poured into the tubular members 40 can be significantly increased compared to the conventional method that uses atmospheric pressure or water pressure. Therefore, the multiple tubular members 40 can be quickly and efficiently submerged, and the submersion work of the tubular members 40 can be stably performed. As a result, a route for general ships can be opened early above the submerged tubular members 40, and safety can be ensured earlier.

[0035] In addition, the method of sinking a tubular member according to the embodiment of the present invention utilizes an air ejector 20A as a pressure reducing means 20 attached to the exhaust port 14 of the sealing lid 10 attached to the tubular member 40A located at one end, as shown in Fig. 1. The air ejector 20A includes a cylindrical body 22 and an ejection part 26, and the ejection part 26 ejects compressed air supplied from a compressor 30 toward one opening 22a of the cylindrical body 22 having openings 22a and 22b at both ends in the inside 22c of the cylindrical body 22. The air ejector 20A having such a structure is attached in such a manner that the other opening 22b on the opposite side to the one opening 22a of the cylindrical body 22 is connected to the exhaust port 14.

[0036] As a result, when the air ejector 20A is operated, as shown in FIG. 3(b), a vacuum state can be generated in the interior 22c of the cylindrical body 22 by the action of compressed air injected by the injection unit 26 toward one opening 22a of the cylindrical body 22. Then, the air in the connected tubular members 40 can be sucked into the interior 22c of the cylindrical body 22 where a vacuum state is generated through the other opening 22b of the cylindrical body 22 connected to the exhaust port 14 of the sealing lid 10, and can be discharged as it is from the one opening 22a of the cylindrical body 22. Therefore, the air in the multiple tubular members 40 can be forcefully discharged through the air ejector 20A, and the multiple tubular members 40 can be quickly and efficiently submerged.

[0037] Furthermore, in the method for sinking a tubular member according to the embodiment of the present invention, as shown in Fig. 3(a), the tubular member 40A located at one end of the multiple connected tubular members 40 is floated on the water OW by a floater 50 when the sinking work is performed. After that, when the work progresses to the extent that the tubular member 40 connected to the tubular member 40A located at one end sinks (see S80 in Fig. 2), the sealing lid 10 and the decompression means 20 are removed from the tubular member 40A located at one end (see S100 in Fig. 2), and new multiple tubular members 40 to be sinking next are connected to the end 42 of the tubular member 40A to which the sealing lid 10 was attached (see S120 in Fig. 2). As a result, the tubular member 40A changes from a state where it was located at one end to a state where it is located between the multiple tubular members 40 that have already sunk and the new multiple tubular members 40.

[0038] Then, the floater 50 is removed from the tubular member 40A located at one end to prepare it for sinking, and then the sinking operation is performed again on the tubular member 40A located at the one end and the new multiple tubular members 40 connected thereto. At this time, the tubular member 40 at the end opposite to the end connected to the tubular member 40A located at one end of the multiple tubular members 40 that were the sinking target in the previous sinking operation is set as the new tubular member 40A located at the one end, and the sealing lid 10 and the decompression means 20 are attached (see S130 in FIG. 2), and the operation is performed while floating on the water OW by the floater 50. By repeatedly performing such sinking operations, the multiple tubular members 40 connected for each sinking operation are set as a unit to be sinked at once, and the length of the tubular members 40 to be sinking is gradually extended, and the tubular members 40 over a long distance can be efficiently sinked. Furthermore, by floating the tubular member 40A located at one end using the floater 50, the work of attaching the sealing lid 10 and the pressure reduction means 20, and the work of removing the sealing lid 10 and the pressure reduction means 20 and connecting the next multiple tubular members 40 can be efficiently performed.

[0039] In addition, the method for sinking a tubular member according to the embodiment of the present invention sinks sand discharge pipes 40 used in pump dredging work as the multiple tubular members 40 to be sinked. Here, pump dredging work is carried out, for example, for the development of a seaway or an anchorage, and is inevitably carried out in a water area where general ships are relatively busy. For this reason, by quickly and efficiently sinking the multiple sand discharge pipes 40 used in pump dredging work as described above, it is possible to open a seaway early in a water area where general ships are relatively busy, and it is possible to prevent the traffic of ships from being blocked for a long period of time. Furthermore, depending on the length of the multiple sand discharge pipes 40 to be sinked, it is possible to contribute to shortening the entire process of pump dredging work. Moreover, as long as the sand discharge pipes 40 are used in work using the sand discharge pipes 40, the same effect can be obtained not only in pump dredging work but also in work such as discharging sediment using a barge unloader ship or a pneumatic transport ship.

[0040] On the other hand, the sealing cover 10 for a tubular member according to an embodiment of the present invention can achieve the same effect as the sinking method for a tubular member according to an embodiment of the present invention, when used in the sinking method for a tubular member according to the embodiment of the present invention as described above. [Explanation of symbols]

[0041] 10: sealing cover for tubular member, 12: cover portion, 14: exhaust port, 20: pressure reducing means, 20A: air ejector, 22: cylindrical body, 22a: one opening, 22b: other opening, 22c: inside of cylindrical body, 26: jet portion, 30: compressor, 40: tubular member (sand discharge pipe), 40A: tubular member located at one end, 42: end portion to which tubular member is not connected, 40B: at least one tubular member provided with a water injection hole, 46: water injection hole, 50: floater, OW: above water, BW: bottom of water

Claims

1. A method for submerging a plurality of connected tubular members on the bottom of a body of water, comprising the steps of: providing a water injection hole in at least one of the plurality of tubular members; The plurality of tubular members are floated on the water by the buoyancy of the air therein; a sealing lid having an exhaust port is attached to an end of a tubular member located at one end of the plurality of tubular members on a side where an adjacent tubular member is not connected; The at least one tubular member is placed in a state in which water can be poured through the water pouring hole; A method for submerging a tubular member, comprising attaching and operating a pressure reducing means for reducing the pressure inside the plurality of tubular members to the exhaust port.

2. The method for sinking a tubular member according to claim 1, characterized in that an air ejector including a cylindrical body and an injection portion for injecting compressed air supplied from a compressor toward one opening of the cylindrical body inside the cylindrical body is attached as the pressure reducing means in a manner that connects the other opening of the cylindrical body to the exhaust port.

3. A method for sinking a tubular member as described in claim 1 or 2, characterized in that after performing a sinking operation while the tubular member located at one end is floated on the water by a floater, the sealing lid and the pressure reducing means are removed from the tubular member located at one end, a plurality of new tubular members are connected to the tubular member located at one end, and the new plurality of tubular members are sinking together with the tubular member located at one end, is repeatedly performed.

4. 3. The method for sinking a tubular member according to claim 1 or 2, characterized in that the plurality of tubular members are sand discharge pipes used in pump dredging work.

5. A sealing cover for tubular members used when sinking a plurality of connected tubular members to the bottom of water, comprising: a cover portion attached to close an end portion of the tubular member located at one end of the plurality of tubular members on a side where an adjacent tubular member is not connected; An exhaust port provided in the lid portion; an air ejector connected to the exhaust port; The air ejector includes a cylindrical body and an injection portion that injects compressed air supplied from a compressor toward one opening of the cylindrical body inside the cylindrical body, the other opening of the cylindrical body being connected to the exhaust port.

Images