Submersible soil transport barge, and sediment unloading method

Abstract

To solve a problem in which, in a situation where there are numerous dredging depressions for collecting sea sand along the coasts of Japan, and, because these depressions are causing deterioration of marine environment, countermeasures such as backfilling are carried out, and it is necessary to take measures to prevent pollution spread when carrying out construction work at sea, to increase prevention of generation and spread of pollutants in order to further promote a project, and to speed up backfilling work, etc., for reducing project costs.SOLUTION: Seabed backfilling in a countermeasure not using a tremie pipe is carried out using a method in which a soil transport barge loaded with sediment submerges, turns over at a specified seabed surface to unload the sediment, and then the empty soil transport barge automatically floats to a water surface. This speeds up the work. In addition, pollution spread prevention measures of the method includes covering a surface of the loaded sediment with a pollution prevention sheet until just before it is unloaded, and then immediately after reversing for unloading sediment, the soil transport barge and the pollution prevention sheet surround the seabed, to perform prevention of generation and spread of pollution caused by unloading sediment, in two stages.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a soil transport ship that transports and unloads soil to be used as bottom filling material, embankment material, etc., and a method of unloading soil. More specifically, the present invention relates to a soil transport ship that unloads soil on the bottom of the water by submerging the soil-laden soil transport ship itself to the bottom of the water and then unloading the soil on the bottom of the water, without dumping the soil on the water surface, and a method of unloading soil on the bottom of the water. [Background technology]

[0002] In order to protect the marine environment, the disposal of waste into the ocean is internationally regulated by the 1972 Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter and the 1996 Protocol to that convention. Japan has ratified these conventions and protocols, and under the Law for the Prevention of Marine Pollution and Maritime Disasters and the Law for Waste Disposal and Cleaning, the disposal of waste into the ocean is prohibited unless it has been approved by the Minister of the Environment after going through the prescribed procedures.

[0003] Meanwhile, in enclosed coastal seas, the concentration of population and industry has led to an increase in the inflow of environmental loads, and the loss of purification functions due to the disappearance of tidal flats and shallow areas caused by coastal landfilling. Red tides and blue tides have also become chronically prone to occur due to the occurrence of hypoxic water masses, which is believed to be partly due to past large-scale dredged depressions, and improvements to the water and bottom sediment environment are required. In order to improve the marine environment, it is important to take measures such as the conservation, restoration, and creation of tidal flats and shallow areas, sand capping, and backfilling dredged depressions, and as a result, more effective use of construction waste soil, dredged soil, and other sediment is expected.

[0004] In order to effectively utilize soil and sand, it is necessary to objectively determine that the soil and sand to be utilized is not waste. Before carrying out the business, business operators who intend to effectively utilize soil and sand must confirm six points: (1) whether the soil and sand is harmful, (2) the quality of the soil and sand, (3) the implementation plan for effective utilization, (4) consideration for the marine environment, (5) the monitoring plan, and (6) the monitoring results. In addition, when carrying out the business, they are required to minimize the impact on the environment to a reasonable extent, for example by implementing construction management to prevent the spread of pollution.

[0005] When using soil and sand as seabed filling material, embankment material, etc., the business operator must clarify that the soil and sand to be used is not waste but a valuable resource. Then, measures to prevent the diffusion of pollution must be implemented. A method of preventing the diffusion of pollution that uses a double-pipe tremie pipe when dumping soil and sand transported by a soil ship into a specified area on the seabed is known (see, for example, Patent Document 1).

[0006] The original tremie pipe method was developed as a method for pouring concrete underwater using a single pipe. When pouring concrete underwater, the concrete material separates due to the influence of water, causing a decrease in strength. The tremie pipe method is used to prevent direct contact between water and concrete as much as possible. The construction procedure is as follows: first, the tremie pipe is placed vertically on the bottom of the water where the concrete is to be poured, and a hopper is attached. Next, a plunger is installed inside the tremie pipe as a boundary to prevent the concrete and water from mixing when pouring concrete. Next, the underwater concrete for underwater use is poured into the tremie pipe. Here, the tremie pipe is gradually raised as the concrete is poured. This is because the concrete pouring stops if the tremie pipe is left on the bottom of the water. In addition, the tip of the tremie pipe is always buried in the concrete at the bottom of the water to prevent the concrete from coming into direct contact with water.

[0007] When a lump of soil is dumped on the sea surface, it separates into fine lumps. The soil lumps that fall underwater have a specific gravity greater than 1. Pollution occurs when soil contains fine clay particles that become suspended solids, and these suspended solids float in the water. The finer the soil lumps are, the easier the suspended solids dissolve, and the more the pollution spreads. The double-pipe tremie pipe method is an application of the single-pipe tremie pipe method. Soil and underwater concrete are completely different materials. If soil is dumped into a single-pipe tremie pipe until it is full, as with underwater concrete, the pipe will always become clogged. If a small amount of soil is dumped to avoid clogging, the soil lumps will fall underwater and separate into small pieces. However, dumping soil using a tremie pipe limits the area where pollution occurs to the bottom layer. However, this tremie pipe effect is the same for both single and double pipes. The advantage of the double-pipe tremie pipe method over the single-pipe tremie pipe method is the efficiency of dumping soil.

[0008] In the double-pipe tremie pipe method of Patent Document 1, an opening is provided near the water surface of the inner pipe, and the opening is provided with a check valve that blocks the outflow of water and sediment from the inner pipe into the double-pipe space sandwiched between the double pipes. When sediment is poured into the inner pipe through a hopper, the sediment sinks down the inner pipe together with seawater, is discharged from the sediment discharge section at the bottom end of the tremie pipe, and is deposited on the seabed. Meanwhile, the polluted seawater undergoes advection diffusion in the bottom layer, but some of it generates a unidirectional circulating flow that passes through the sediment discharge section, the double-pipe space, and the opening. The effect is to prevent the clogging of sediment in the inner pipe, and to increase the amount of sediment poured per unit time compared to the single-pipe tremie pipe method, which does not generate a circulating flow. In addition, since the polluted water is circulated and stored, it is said to have the effect of reducing the turbidity that flows out of the tremie pipe. In addition, a new measure has been taken to surround the sediment release area and the seabed with canvas sheets, reducing the rapid advection and diffusion of polluted water around the bottom layer immediately after the sediment is dumped. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 5393376 Summary of the Invention [Problem to be solved by the invention]

[0010] When dumping soil and sand into a specified area on the seabed, a pollution diffusion prevention method using a double-pipe tremie pipe is used. In this method, soil and sand (soil lumps) are dumped into the inner tremie pipe with a backhoe. Even inside the tremie pipe, the soil lumps break down into small pieces as they fall into the water, generating a lot of pollutants. The effect of the double tremie pipe method is to smoothly send soil and sand to the seabed by circulating flow. And, the area where pollution occurs is limited to the bottom layer. This has achieved a soil dumping speed that was not achieved with the conventional single-pipe tremie pipe method. In contrast, the first object of the present invention is to prevent soil and sand from falling into the seabed from the sea surface at any time. And, by avoiding contact between the soil surface and water, the generation of pollutants and the suppression of pollution diffusion are brought close to the limit. The second object is to speed up the soil unloading work by eliminating the long time of repeated soil dumping by excavation machines such as backhoes. In addition, the removal of soil and sand while taking into consideration the water quality environment is not limited to the bottom of the sea, but also applies to the bottom of lakes and rivers.

[0011] The first objective of the present invention is to minimize the generation of pollutants in the soil and the suppression of the spread of pollutants. The second objective is to speed up the soil unloading work. The basic means for this are the structure and function of the soil transport ship, and the method of unloading the soil. First, the structure and function of the soil transport ship are to integrate multiple sealed tanks around the hold, and most of these sealed tanks function as ballast tanks. The soil transport ship is a submersible soil transport ship that has a diving function by controlling the inflow of ballast water and is equipped with a remote-controlled underwater inversion device for the soil transport ship. The method of unloading the soil of the submersible soil transport ship is performed by the soil transport ship loaded with soil submerging and inverting at a specified seabed surface, and the empty soil transport ship automatically rises to the sea surface due to its superior buoyancy.

[0012] In the process of unloading soil by the soil transport ship, the soil transport ship is submerged to a specified seabed surface. In other words, soil does not fall underwater from the sea surface to the seabed. This has the effect of suppressing the occurrence and spread of water pollution. Next, the soil transport ship is turned over sideways at a specified seabed surface to unload the soil and then rises to the surface. In this system, multiple closed empty tanks function as ballast tanks, and the soil floats up when the weight of the soil is unloaded by the planned remaining buoyancy. In other words, since the soil unloading method of the present invention is a submersible soil transport ship that can easily adapt to the seabed depth, there is no process of erecting a tremie pipe. In addition, instead of the long-term loading of soil by an excavation machine, unloading soil by turning over sideways of the soil transport ship, which is completed in a short time, promotes the speed-up of soil unloading work.

[0013] The diving function of the soil transport ship of the present invention reduces buoyancy by injecting a necessary amount of ballast water into the hold and the sealed tank. The inflow of ballast water is first filled to a level slightly above the top of the soil in the hold, and then the necessary amount of ballast water is injected into the sealed tanks at the bow and stern while checking the horizontal balance of the soil transport ship from the water surface of the hold. Finally, the top of the hold is filled with ballast water. The feature of the diving function of the soil transport ship is to maintain the specific gravity of the soil transport ship's underwater weight appropriately larger than 1, thereby ensuring an optimal underwater weight that makes it easy to operate the soil transport ship underwater. Here, the underwater weight of the soil transport ship is the soil transport ship's own weight plus the weight of the soil loaded underwater and the weight of the ballast water. If the specific gravity of this underwater weight is larger than 1, the soil transport ship will submerge. However, if it is too large, a large amount of energy is required to operate the soil transport ship, and as a result, a large support ship is required. Conversely, if it is too small, it will be swept away by the ocean current, making it difficult to operate the soil transport ship to unload it. By setting the soil transport ship to its optimum underwater weight, the soil transport ship can be stabilized while being turned over easily. This optimum underwater weight varies depending on the conditions of the sea area during the work. The specific gravity of the soil transport ship's optimum underwater weight is assumed to be around 1.1 to 1.3.

[0014] The submersible soil transport ship of the present invention must ensure an optimum underwater weight that differs depending on the conditions of the sea area. To achieve this, the soil transport ship needs to have an accurate adjustment function that makes the specific gravity of the underwater weight appropriately greater than 1. For this reason, most of the multiple closed tanks of the soil transport ship are equipped with an automatic ballast water inflow device that automatically opens and closes multiple air and water vents. This device allows the submersible soil transport ship of the present invention to accurately adjust the amount of ballast water inflow, making it possible to easily ensure an optimum underwater weight that exceeds any specific gravity of 1.

[0015] The submersible soil transport vessel of the present invention is submersible. The automatic ballast water inlet device must operate underwater. Therefore, the airtight covers of the air and water vents of the automatic ballast water inlet device are powered by replaceable underwater batteries to enable underwater operation.

[0016] The submersible soil transport ship of the present invention unloads soil by submerging the soil transport ship and flipping it over laterally on a specified seabed surface. For this reason, the soil transport ship of the present invention is equipped with an underwater flipping device. There are two types of underwater flipping devices depending on the installation position. The first is an underwater flipping device that is installed at the center of the ship. This device is installed at two central positions equidistant from the center of gravity of the hull longitudinally, and groove-shaped flipping rope guides are attached to the transverse outer circumference of the hull, which is the bottom of the ship, on both sides of the hull. A flipping rope is wound around this and stretched on the top of the hold, with its midpoint coinciding with the midpoint of the hold width. This rope is then fixed to the top of both sides of the hold and wrapped around the groove of the flipping rope guide to embrace the outer circumference of the hull. Both ends of the rope are extended to the top of the hold on the opposite side, and hook receivers are attached to both ends of the rope. The second underwater flipping device is an flipping device that is installed at two points, the bow and the stern, or either one of them. This device is a flipping plate with a groove on the outer periphery, and is fixed to the hull. The midpoint of one flipping rope is fixed to the top of the flipping plate, and the rope is wound around the outer periphery groove once or more, with both ends of the rope extended to the top of the flipping plate, and hook receivers are attached to both ends of the rope. Usually, the tip of the flipping rope is hooked and held on the top of the hull side, or on a fixed hook attached to the hull near the top of the flipping plate. In addition to the hook receivers, buoys are attached to both ends of the rope. The role of the buoys is to make it easier to retrieve the flipping rope if it is accidentally dropped into the sea. The submersible soil transport ship of the present invention makes it possible to unload soil by flipping it sideways on the seabed surface using these underwater flipping devices.

[0017] The first object of the present invention is to provide a measure to suppress both the generation of pollutants in the soil and the suppression of the diffusion of pollutants, and to maximize the effect of the measures. The pollution prevention sheet with the step-by-step function of the present invention is composed of a plurality of pollution prevention sheets covering the surface of the soil in the hold. One end of each sheet is fixed to the inside of the hold. First, the soil is covered with the vertical sheets in the longitudinal direction of the hull, and then the horizontal sheets in the transverse direction of the hull. The multiple pairs of horizontal sheets are overlapped and temporarily fixed in place in the center of the hold, and the horizontal sheets in the reversal direction of the submersible soil transport ship's soil unloading are the upper surface of the overlap, and the overlap of the horizontal sheets is temporarily fixed so that they are separated by the weight of the soil. The overlapping of the pollution prevention sheets is specified here so that the sheets cannot be turned over when the soil transport ship is turned over laterally. The pollution prevention sheet with the step-by-step function corresponds to a solution for suppressing the generation of pollutants by first covering the surface of the loaded soil with the pollution prevention sheet until just before the submersible soil transport ship unloads the soil. In other words, an interface is created between the entire soil and sand loaded in the hold and the water, preventing direct contact between them and suppressing the generation of pollutants. Next, the pollution prevention sheet corresponds to the solution for suppressing the spread of pollution immediately after the soil unloading is reversed. In other words, the soil transport ship and the pollution prevention sheet enclose the seabed surface and suppress the spread of pollution from the soil unloading. The submersible soil transport ship of the present invention is fitted with a pollution prevention sheet, which has a step-by-step function of suppressing the generation of pollutants and the spread of pollution in two stages, making it possible to maximize the effectiveness of this measure.

[0018] The gist of this invention is a method for unloading soil by submerging a soil transport ship and flipping it sideways. In this method for unloading soil from a submersible soil transport ship equipped with two underwater flipping devices consisting of a flipping rope and a flipping rope guide around which the flipping rope is wound, or a flipping plate, two support ships equipped with multiple winches are attached to both sides of the center of the soil transport ship, or to the bow and stern, and four hook receivers at both ends of the flipping rope of the two underwater flipping devices are connected to the hooks of the operation ropes of the corresponding four winches of the two support ships. Next, the specific gravity of the soil transport ship's underwater weight is increased to more than 1 by increasing the ballast water, and submersion is started, and the operation rope is simultaneously let out from the four winches of the support ship connected to the underwater flipping device. When the submersible soil transport ship stops on the seabed, the letting out of the operation rope is stopped. To remove soil and sand, the operating ropes of the two winches on one side of the four vessels are reeled in at a length equal to half the transverse circumference of the hull or half the circumference of the inversion plate, while the other two winches send out operating ropes of the same length, thereby simultaneously operating the inversion ropes of the underwater inversion device and remotely inverting the submersible soil-carrying vessel on the seabed.

[0019] The submersible soil transport ship of the present invention is equipped with an underwater inversion device that uses a winding method for inversion rope, making it possible to unload soil on the seabed. The soil unloading method of the present invention does not use a tremie pipe, so there is no process of erecting the tremie pipe each time, and the seabed depth can be adjusted by adjusting the length of the winch operating rope, making it quick. The soil unloading work is completed with a single inversion of the soil transport ship, and the empty soil transport ship automatically surfaces, greatly speeding up the work. In addition, since the soil unloading of the present invention does not drop soil underwater, it is very effective in suppressing the generation of pollutants. A small submersible soil transport ship can be made with just one underwater inversion device. In this case, the underwater inversion device has a fixed inversion plate. Effects of the Invention

[0020] The method of unloading soil using a submersible soil transport ship of the present invention does not use tremie pipes, and is carried out by submerging the soil transport ship and turning it sideways once at a specified seabed surface. The depth of the seabed can be easily adjusted by adjusting the length of the winch rope. The empty soil transport ship's buoyancy will be stronger and it will automatically rise to the sea surface. In this way, the soil unloading method of the present invention has greatly promoted the speeding up of work. Furthermore, because the soil unloading method of the present invention does not drop soil underwater, it is highly effective in suppressing the generation of pollutants.

[0021] The submersible soil transport ship of the present invention is fitted with a pollution prevention sheet that functions in stages, which covers the surface of the loaded soil until just before it is unloaded, creating an interface between the soil and the water and suppressing the generation of pollutants. Then, just after the soil unloading is reversed, the seabed is enclosed with the soil transport ship and the pollution prevention sheet to suppress the spread of pollution from the unloading of the soil. In this way, the submersible soil transport ship of the present invention is fitted with a pollution prevention sheet that functions in stages to suppress the generation of pollutants and the spread of pollution in two stages, making it possible to maximize the effectiveness of the countermeasures. [Brief description of the drawings]

[0022] [Figure 1] FIG. 2 is a side view of the soil transport boat of the present invention having an underwater inversion device in the center of the boat. [Diagram 2] FIG. [Diagram 3] 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] FIG. 2 is a side view of the soil transport boat of the present invention equipped with underwater inversion devices at the bow and stern. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] This is a plan view of a support vessel attached to a soil transport vessel of the present invention, which has an underwater inversion device installed in the center of the vessel. [Figure 8] 8 is a cross-sectional view of FIG. 7 taken along line B-B. [Figure 9] This is a diagram showing the submerged state of a soil transport ship equipped with an underwater inversion device in the center of the ship during the process of unloading soil. [Figure 10]This is also a picture of the soil transport barge turning over during the soil unloading process. [Figure 11] This is also a picture of the soil transport ship completing the soil unloading process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of the present invention will be described with reference to Figs.

[0024] Fig. 1 is a side view of the submersible soil transport ship of the present invention, which is equipped with an underwater flipping device in the center of the ship. Fig. 2 is a plan view of the same. Fig. 3 is a cross-sectional view along the line A-A in Fig. 2. In the figures, 1 is a submersible soil transport ship, 11 is a hold, 12 is a sealed tank, 13 is a hold bulkhead, 14 is a flipping rope guide, 16 is a flipping rope, 17 is a hook receiver, 18 is a pollution prevention sheet, 19 is a drainage pump, 3 is soil and sand, and 4 is the sea surface.

[0025] The submersible soil transport ship 1 of the present invention has a plurality of sealed tanks 12 integrated around the hold 11, and most of these sealed tanks 12 function as ballast tanks. As a result, the soil transport ship 1 has a submersible function by controlling the inflow of ballast water, and is equipped with an underwater flipping device for the soil transport ship 1 that can be remotely operated. The arrangement of the sealed tanks 12 is shown in the figure as an example at the bow, stern, and side. The sealed tanks 12 at the bow and stern are dedicated to ballast tanks. The sealed tanks 12 on the side of the hull shown in Figure 8 below are dedicated buoyancy tanks that bear the buoyancy equivalent to the weight of the soil transport ship 1. The underwater flipping device in Figures 1 to 3 is a device consisting of a flipping rope 16 and a flipping rope guide 14 around which the rope is wound. Also, as shown in Figure 3, the positions of the hold bulkhead 13 and the flipping rope 16 overlap. This is to prevent the flipping rope 16 from interfering with the pollution prevention sheet 18, which functions in stages, when the submersible soil transport ship 1 flips over to unload soil. In addition, the hold bulkhead 13 has the effect of increasing the rigidity and reinforcing the hull.

[0026] The method for unloading the soil from the soil ship 1 is as follows: the soil ship 1 loaded with soil 3 submerges and turns over at a specified seabed surface 4, and the empty soil ship 1 automatically rises to the surface. The soil ship 1 returns to its original state by turning over at the sea surface 4. Then, the ballast water in the sealed tank 12 is drained by the drainage pump 19, and the soil ship 1 regains the appropriate buoyancy.

[0027] Fig. 4 is a side view of the submersible soil transport ship 1 of the present invention with underwater flipping devices attached to the bow and stern. Fig. 5 is a plan view of the same. Fig. 6 is a front view of the bow or stern of the same. In the figures, 15 is a flipping table. The flipping table 15 is fixed to the hull of the soil transport ship 1.

[0028] Figure 7 is a plan view of a submersible soil-carrying ship 1 of the present invention with an underwater inversion device attached to the center of the ship, and a support ship 2 attached to it. Figure 8 is a B-B cross-sectional view of Figure 7. In the figure, 2 is the support ship, 21 is a winch, 22 is an operating rope, 23 is a fixed pulley, and 24 is an operating tower. Figure 8 is a cross-sectional view of the submersible soil-carrying ship 1, and shows the sealed tank 12 on the side of the hull.

[0029] When the submersible soil transport ship 1 is unloading soil, two support ships 2 equipped with multiple winches 21 are attached to both sides of the center of the soil transport ship 1, and a total of four hook receivers 17 on both ends of the reversing ropes 16 of the two underwater reversing devices are connected to the hooks of the operating ropes 22 of the corresponding four winches 21 on the two support ships 2. The reversal of the submersible soil transport ship 1 for unloading soil is performed by remote control from the support ship 2.

[0030] FIG. 9 shows the process of unloading sand by a submersible soil transport ship 1 with an underwater inversion device attached to the center of the ship, and is a diagram of the soil transport ship 1 diving. When diving, ballast water is first filled to a level slightly above the top of the soil 3 in the hold 11, and then the required amount of ballast water is poured into the closed tanks 12 at the bow and stern while checking the horizontal balance of the soil transport ship 1 from the water surface of the hold 11. Finally, the hold 11 is filled with ballast water up to the top and diving begins. The feature of the diving function of the soil transport ship 1 is to achieve an optimal underwater weight that makes it easy for the soil transport ship 1 to operate underwater. The specific gravity of the optimal underwater weight of the soil transport ship 1 is assumed to be about 1.1 to 1.3. By ensuring the optimal underwater weight, the support ship 2 is prevented from becoming larger. In addition, the submersible soil transport ship 1 is fitted with a pollution prevention sheet 18, which serves as a step function, so that the surface of the soil 3 is covered with the pollution prevention sheet 18 until just before the soil is unloaded, creating an interface between the soil 3 and the water and suppressing the generation of pollutants.

[0031] FIG. 10 is a diagram showing the inversion of the submersible soil ship 1 on the seabed 5 during the soil unloading process. The soil ship 1 with the optimal underwater weight is submerged by simultaneously letting out the operating ropes 22 from the four winches 21 of the support ship 2 connected to the underwater inversion device. The soil ship 1 stops at the seabed 5 by stopping the sending out of the operating ropes 22. The operating capacity and lifting capacity of the support ship 2 correspond to the optimal underwater weight of the soil ship 1. In the method of inverting the soil ship 1 for unloading soil, the four winches 21 are operated, and two winches 21 on one side rewind the operating ropes 22 with a length half the cross-sectional outer perimeter of the soil ship 1, while the other two winches 21 let out the operating ropes 22 with the same length to invert the soil ship 1. Here, the soil ship 1 is pulled up by half the length of its width and inverted, so that the soil unloading position can be performed without shifting.

[0032] FIG. 11 shows the completion of the unloading of soil by the submersible soil transport ship 1 during the soil unloading process. The pollution prevention sheet 18 of the soil transport ship 1 has a step function. Immediately after the soil unloading is turned around, the soil transport ship 1 and the pollution prevention sheet 18 surround the seabed surface 5, thereby suppressing the spread of pollution caused by the unloading of soil. Here, when the soil transport ship 1 turns around and unloads the soil, negative pressure is generated at the bottom of the hold 11, causing the soil 3 to collapse, increasing the contact area between the soil 3 and the water, which may increase the generation of pollutants. Even if there is a pollution prevention sheet 18 with a step function, it is better to prevent this. In this case, it is better to attach multiple strip-shaped drain sheets to the inside of the hold 11 to eliminate the generation of negative pressure. [Explanation of symbols]

[0033] 1 Submersible soil transport ship 11. Hold 12. Sealed Tank 13 Hold bulkhead 14 Reversible rope guide 15 Inversion Board 16 Reversal rope 17 Hook receiver 18 Anti-pollution sheet 19 Drainage pump 2. Support vessels 21 Winch 22 Operation rope 23 Fixed pulley 24 Operation Building 3. Soil 4 sea level 5 Seabed surface

Claims

1. A submersible soil transport ship that transports and unloads soil has multiple sealed tanks integrated around the cargo hold, with most of these sealed tanks functioning as ballast tanks, has a diving function that controls the inflow of ballast water, and is equipped with a remote-controlled underwater soil transport ship inversion device, and the soil unloading method of the soil transport ship is characterized by a soil unloading method in which the soil transport ship loaded with soil submerges and inverts at a specified seabed surface, and the empty soil transport ship automatically rises to the water surface.

2. In the submersible soil transport ship of claim 1, the diving function of the soil transport ship is to reduce buoyancy by injecting the necessary amount of ballast water into the cargo hold and multiple sealed tanks, and by maintaining the specific gravity of the underwater weight of the soil transport ship appropriately greater than 1, an optimal underwater weight is secured to facilitate underwater operation of the soil transport ship, stabilizing the submersion of the soil transport ship and facilitating the inversion operation of the soil transport ship.

3. In the submersible soil transport ship of claim 1, the majority of the multiple sealed tanks are ballast tanks of the soil transport ship equipped with an automatic ballast water inflow device that automatically opens and closes multiple air vents and water vents, and this automatic device has the function of accurately adjusting the inflow of ballast water to ensure any optimal underwater weight.

4. 4. The automatic ballast water inlet device according to claim 3, wherein the airtight covers of the air vent and the water vent are automatically opened and closed using a replaceable underwater battery as a power source.

5. 2. A submersible soil transport ship equipped with an underwater inversion device as claimed in claim 1, wherein the underwater inversion devices are installed at two positions equidistant from the center of gravity of the longitudinal section of the hull, a groove-shaped inversion rope guide is attached to the transverse outer periphery of the hull, the inversion rope is fixed to the top of both sides of the hold with its midpoint coinciding with the midpoint of the hold width, and is then wound around the outer periphery of the hull to embrace it in line with the grooves of the inversion rope guide, both ends of the rope are extended to the top of the hold on the opposite side, and hook receivers are attached to the ends of the ropes, and the submersible soil transport ship is equipped with an underwater inversion device consisting of an inversion rope and an inversion rope guide around which the inversion rope is wound.

6. A submersible soil transport ship equipped with the underwater inversion device of claim 1, wherein the underwater inversion device has an inversion plate with a groove on its outer periphery fixed to two locations, or either one of the locations, at the bow and stern, and the midpoint of a inversion rope is fixed to the top of the outer periphery of the inversion plate, and the rope is wound around the groove of the inversion plate once or more, both ends of the rope are extended to the top of the inversion plate, and hook receivers are attached to both ends of the rope, characterized in that the submersible soil transport ship is equipped with an underwater inversion device consisting of the inversion rope and the inversion plate around which the rope is wound.

7. In the submersible soil transport ship fitted with a pollution prevention sheet with a stepped function that covers the surface of the soil in the hold of claim 1, this pollution prevention sheet consists of a plurality of pollution prevention sheets that cover the surface of the soil in the hold, one end of these sheets is fixed to the inside of the hold, the soil is first covered with a vertical sheet in the longitudinal direction of the hull, and then a plurality of pairs of horizontal sheets in the transverse direction of the hull are overlapped and temporarily fixed in the center of the hold, with the horizontal sheet fixed on the side in the reversal direction of the soil unloading of the submersible soil transport ship being the upper surface of the overlap, and the temporary fastening is performed by separating the soil by its own weight, the surface of the loaded soil is covered with the pollution prevention sheet until just before the submersible soil transport ship unloads the soil, and immediately after the soil unloading is reversed, the soil transport ship and the pollution prevention sheets surround the seabed surface, thereby suppressing the spread of pollution from the soil unloading.

8. In the method for unloading soil from a submersible soil transport ship equipped with two underwater flip-over devices as claimed in claims 5 and 6, two support ships equipped with multiple winches are attached to both sides of the center of the soil transport ship, or to the bow and stern, and four hook receivers at both ends of the flipping ropes of the two underwater flip-over devices are connected to the hooks of the operating ropes of the corresponding four winches of the two support ships. Then, the specific gravity of the soil transport ship in water is increased to more than 1 by increasing the ballast water, and submersion is started. The method for unloading soil from a submersible soil-carrying vessel is characterized in that an operating rope is simultaneously let out from both winches and stopped on the seabed, and two winches on one side of the four vessels rewind an operating rope half the length of the hull cross circumference or half the length of the inversion plate circumference, while the other two winches let out an operating rope of the same length to invert the soil-carrying vessel, and the inversion rope of the underwater inversion device is operated simultaneously by four winches on two support vessels to remotely invert the submersible soil-carrying vessel on the seabed.

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