Scrap prevention mat installation device and scouring prevention mat installation method

Abstract

To provide a scour prevention mat laying device and a scour prevention mat laying method that can easily position and lay a scour prevention mat on a water bottom while ensuring soundness of the mat.SOLUTION: A scour prevention mat laying device 1 comprises: a main body 8 on which a scour prevention mat 7 is placed; a mat movement auxiliary structure, on an upper part of the main body 8, for moving the scour prevention mat 7 in a sending-out direction; and a hanging portion 10 for hanging up the main body 8. The scour prevention mat laying device 1 is used, which can lay the scour prevention mat 7 on a water bottom 15 by tilting the main body 8 in the sending-out direction with the scour prevention mat 7 placed on the main body 8 and hung down to the water bottom 15, and moving the scour prevention mat 7 from the main body 8 to the water bottom 15 by the mat movement auxiliary structure. When laying, the scouring prevention mat 7 is placed on the main body 8, the main body 8 is hung down to the water bottom 15, the main body 8 is tilted, and the scouring prevention mat 7 is moved to the front of the main body 8 while the main body 8 is moved backward.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a device for laying an erosion prevention mat and a method for laying an erosion prevention mat.

Background Art

[0002] Conventionally, in underwater structures such as the foundations of offshore wind power generation facilities, dikes, and bridge piers, the problem of erosion, where the surrounding sediment is sucked out or dug in by the flow of water, has been an issue. This phenomenon is due to the acceleration associated with local water flow disturbances caused by the structure and the generation of vortices. As a method for constructing an erosion prevention work to prevent erosion, there is a method in which a covering such as an impermeable sheet or mat is suspended from a scaffold with a wire in a deployed state and then sedimented and laid on the bottom of the water around the underwater structure (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the construction method of the erosion prevention work of Patent Document 1, when the covering is suspended with a wire, it is likely to sway horizontally, the posture is not stable, and it is difficult to position it for installation on the bottom of the water. Also, when constructing an erosion prevention work around a large underwater structure, if the covering is divided, the construction period becomes long, and if a large-area covering is used, the covering may be damaged due to deflection during suspension.

[0005] The present invention has been made in view of the above-described problems, and an object thereof is to provide an erosion prevention mat laying device and an erosion prevention mat laying method that can be easily positioned and laid on the bottom of the water while ensuring the integrity of the erosion prevention mat. [[ID=*41]]

Means for Solving the Problems

[0006] To achieve the aforementioned objective, the first invention is a device for laying a scour prevention mat on the seabed, comprising: a main body on which the scour prevention mat is placed; a mat movement assist structure located on the upper part of the main body for moving the scour prevention mat in the discharge direction; and a suspension part for lifting the main body. With the scour prevention mat placed on the main body and suspended from the seabed, the main body is tilted in the discharge direction, and the scour prevention mat is moved from the main body to the seabed by the mat movement assist structure, thereby enabling the scour prevention mat to be laid on the seabed. Furthermore, in the main body, at least a portion of the area on which the scouring prevention mat is placed is provided with a plurality of nozzles directed upward and outward as a mat movement assist structure, and friction between the main body and the scouring prevention mat is reduced by ejecting seawater or seawater containing air from the plurality of nozzles. This is a scour prevention mat laying device characterized by the following features.

[0007] In the first invention, the scour prevention mat is placed on the main body of the scour prevention mat laying device and lowered to the seabed. This ensures that the scour prevention mat does not bend or flex during lowering, and that there is no concern about damage due to stress concentration near the lifting fittings partially embedded in the mat, thus ensuring its integrity. Furthermore, since the main body that has been lowered to the seabed is tilted to move the scour prevention mat from the main body to the seabed, positioning for laying is easier compared to when the scour prevention mat is lowered individually. Furthermore, by arranging multiple nozzles to reduce friction between the main body and the anti-scouring mat, the anti-scouring mat can move more easily in the direction of discharge when the main body is tilted toward the discharge direction.

[0008] In the main body, it is desirable that a plurality of rollers are arranged as a mat movement assist structure in at least a portion of the area on which the scour prevention mat is placed, and that at least some of the rollers are drive rollers, and that the scour prevention mat can be moved by the drive rollers. The same applies to the inventions described in Sections 2-6 below. This allows the scouring prevention mat placed on the main body to be pulled by the drive rollers while being fed out by the remaining rollers when the main body is tilted in the feeding direction.

[0009] In the main body, a sliding plate for reducing friction may be provided as a mat movement assistance structure in at least a portion of the area on which the scour prevention mat is placed. The same applies to the inventions described in Sections 2-6 below. sliding BoardBy positioning the mat in a way that reduces friction between the main body and the anti-scouring mat, the anti-scouring mat will move more easily in the direction of discharge when the main body is tilted toward the discharge direction.

[0010] The second invention is a device for laying an anti-scouring mat on the bottom of a body, comprising: a main body on which the anti-scouring mat is placed; a mat movement assist structure located on the upper part of the main body for moving the anti-scouring mat in the discharge direction; and a suspension part for lifting the main body. With the anti-scouring mat placed on the main body and suspended from the bottom of the body, the main body is tilted in the discharge direction, and the anti-scouring mat is moved from the main body to the bottom of the body by the mat movement assist structure, thereby enabling the anti-scouring mat to be laid on the bottom of the body. In the main body, multiple rollers are arranged in the area where the scouring prevention mat is placed, serving as a mat movement assistance structure. Between the rollers, gaps are formed that penetrate vertically, allowing water and sand to pass through. This is a scour prevention mat laying device characterized by the following features. . This design allows water to pass through the gaps between the rollers when the main body is lowered into the water, reducing water resistance on the underside of the main body. As a result, the movement of the main body is reduced, making positioning easier. Additionally, sand passing through the gaps between the rollers and between the rollers and the main body prevents malfunctions of the rollers due to clogging.

[0011] The third invention is a device for laying an anti-scouring mat on the bottom of a body, comprising: a main body on which the anti-scouring mat is placed; a mat movement assist structure located on the upper part of the main body for moving the anti-scouring mat in the discharge direction; and a suspension part for lifting the main body. With the anti-scouring mat placed on the main body and suspended from the bottom of the body, the main body is tilted in the discharge direction, and the anti-scouring mat is moved from the main body to the bottom of the body by the mat movement assist structure, thereby enabling the anti-scouring mat to be laid on the bottom of the body. In the main body, a hole is formed approximately in the center of the area where the scouring prevention mat is placed, which penetrates vertically and allows water to pass through. This is a scour prevention mat laying device characterized by the following features. . As a result, when the main body is lowered into the water, water passes through the holes, reducing water resistance on the underside of the main body. This reduces the movement of the main body and makes positioning easier.

[0012] The fourth invention is a device for laying an anti-scouring mat on the bottom of a body, comprising: a main body on which the anti-scouring mat is placed; a mat movement assist structure located on the upper part of the main body for moving the anti-scouring mat in the discharge direction; and a suspension part for lifting the main body. With the anti-scouring mat placed on the main body and suspended from the bottom of the body, the main body is tilted in the discharge direction, and the anti-scouring mat is moved from the main body to the bottom of the body by the mat movement assist structure, thereby enabling the anti-scouring mat to be laid on the bottom of the body. The main body has stoppers provided in the front and rear directions relative to the direction in which the scouring prevention mat is fed out, and guide members arranged on both sides in the direction in which the scouring prevention mat is fed out, and the stopper provided in the front direction in the direction in which the scouring prevention mat is fed out is movable and can be released after the mat has reached the bottom. This is a scour prevention mat laying device characterized by the following: . This prevents the scour prevention mat from shifting position when the main unit is lowered, thanks to the stopper and guide members. Furthermore, when the main unit is tilted, the stopper at the front in the feeding direction can be released, allowing the scour prevention mat to move along the guide members.

[0013] The fifth invention is a device for laying an anti-scouring mat on the bottom of a body, comprising: a main body on which the anti-scouring mat is placed; a mat movement assist structure located on the upper part of the main body for moving the anti-scouring mat in the discharge direction; and a suspension part for lifting the main body. With the anti-scouring mat placed on the main body and suspended from the bottom of the body, the main body is tilted in the discharge direction, and the anti-scouring mat is moved from the main body to the bottom of the body by the mat movement assist structure, thereby enabling the anti-scouring mat to be laid on the bottom of the body.The hanging part is a pulley, which is arranged in front of and behind the main body with respect to the feeding direction of the anti-erosion mat. A wire position adjustment mechanism for moving and fixing the wire is provided between the front and rear pulleys. The wire arranged through the wire position adjustment mechanism and the front and rear pulleys can be lifted upward. In a state where the wire is loosened, the front and rear balance of the suspension can be changed by moving the wire between the front and rear pulleys by the wire position adjustment mechanism. This is a scour prevention mat laying device characterized by the following features. . Thus, the inclination of the main body can be easily adjusted and held at a certain inclination.

[0014] The sixth invention is a device for laying an anti-scouring mat on the bottom of a body, comprising: a main body on which the anti-scouring mat is placed; a mat movement assist structure located on the upper part of the main body for moving the anti-scouring mat in the discharge direction; and a suspension part for lifting the main body. With the anti-scouring mat placed on the main body and suspended from the bottom of the body, the main body is tilted in the discharge direction, and the anti-scouring mat is moved from the main body to the bottom of the body by the mat movement assist structure, thereby enabling the anti-scouring mat to be laid on the bottom of the body. The main body has a tip part near the end in the feeding direction of the anti-erosion mat, and a gradient is formed on the upper surface such that it approaches the lower surface toward the tip. This is a scour prevention mat laying device characterized by the following: . Thus, when the main body is tilted, the step between the upper surface of the tip part and the bottom of the water can be reduced. Also, the movement of the main body in the tilted state becomes easy.

[0015] The 7 invention is wash a method for laying an anti-erosion mat using an anti-erosion mat laying device, The scour prevention mat laying device is a device for laying a scour prevention mat on the seabed, comprising: a main body on which the scour prevention mat is placed; a mat movement assist structure located on the upper part of the main body for moving the scour prevention mat in the discharge direction; and a suspension part for lifting the main body, wherein the scour prevention mat can be laid on the seabed by tilting the main body toward the discharge direction with the scour prevention mat placed on the main body and suspended from the seabed, and moving the scour prevention mat from the main body to the seabed using the mat movement assist structure. comprising: a step a of placing an anti-erosion mat on the main body; a step b of suspending the main body under water; and a step c of tilting the main body and laying the anti-erosion mat on the bottom of the water while moving the anti-erosion mat forward of the main body while moving the main body backward.

[0016] The 7 invention places an anti-erosion mat on the main body and suspends it under water, so there is no bending or the like in the anti-erosion mat during suspension, and there is no concern about damage due to stress concentration near the hanging fitting partially embedded in the mat, ensuring soundness. Also, since the main body is tilted and moved backward while moving the anti-erosion mat forward of the main body, the anti-erosion mat can be laid on the bottom of the water by positioning for laying due to the landing of the main body.

[0017] Before the step c, it is desirable to drive an anchor connected to the erosion prevention mat into the water bottom. Thereby, when moving the erosion prevention mat forward of the main body while moving the main body backward, the erosion prevention mat is not dragged backward following the main body.

Effect of the Invention

[0018] According to the present invention, it is possible to provide an erosion prevention mat laying device and an erosion prevention mat laying method that can be easily positioned and laid on the water bottom while ensuring the soundness of the erosion prevention mat.

Brief Description of the Drawings

[0019] [Figure 1] (a) is a view showing the whole of the erosion prevention mat laying device 1, and (b) is a cross-sectional view taken along line A-A shown in (a). [Figure 2] (a) is a plan view of the erosion prevention mat 7, (b) is a cross-sectional view in the vertical direction of the erosion prevention mat 7, and (c) is a view showing a method of placing the erosion prevention mat 7 on the main body 8. [Figure 3] (a) and (b) are views showing the step of suspending the main body 8 to the water bottom 15, (c) is a view showing the step of laying the erosion prevention mat 7, and (d) is a view showing the step of completing the laying of the erosion prevention mat 7 and recovering the main body 8. [Figure 4] (a) is a view showing the whole of the erosion prevention mat laying device 1a, and (b) is a cross-sectional view taken along line B-B shown in (a). [Figure 5] (a) is a view showing the step of loosening the wire 11a, (b) is a view showing the step of moving the position of the wire 11a, and (c) is a view showing the step of tilting the main body 8a. [Figure 6] (a) is a view showing the whole of the erosion prevention mat laying device 1b, and (b) is a cross-sectional view taken along line D-D shown in (a). [Figure 7] (a) is a plan view of the erosion prevention mat laying device 1c, (b) is a view showing the step of suspending the main body 8, and (c) is a view showing the step of laying the erosion prevention mat 7. [Figure 8](a) is a plan view of the scour prevention mat laying device 1d, and (b) is a plan view of the scour prevention mat laying device 1e. [Figure 9] Plan view of the scour prevention mat installation device 1f. [Figure 10] (a) is a vertical cross-sectional view of the scour prevention mat laying device 1g, (b) is a vertical cross-sectional view of the scour prevention mat laying device 1h, and (c) is a plan view of the scour prevention mat laying device 1i. [Modes for carrying out the invention]

[0020] Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

[0021] [First Embodiment] Figure 1 shows a scour prevention mat laying device 1. Figure 2 shows a scour prevention mat 7 and a method for placing the scour prevention mat 7 on the main body 8. In the first embodiment, the scour prevention mat 7 shown in Figure 2 is laid on the seabed using the scour prevention mat laying device 1 shown in Figure 1.

[0022] As shown in Figure 1(a), the scour prevention mat laying device 1 consists of a main body 8, multiple rollers 9, a lifting section 10, etc. The main body 8 is the part on which the scour prevention mat 7 is placed. The multiple rollers 9 are a mat movement assist structure located on the upper part of the main body 8 to move the scour prevention mat 7 in the feeding direction. The lifting section 10 is provided to lift the main body 8. In the scour prevention mat laying device 1, the feeding direction of the scour prevention mat 7 and the front of the main body 8 correspond to the right direction in Figure 1(a). The number of lifting sections 10 may be greater than or equal to the total weight and the strength of the wire 11, and should be determined as appropriate.

[0023] The main body 8 is a steel frame that is roughly rectangular in plan view. The main body 8 has a stopper 12, a lateral guide 13 which is a guide member, and a tip 14. The stopper 12 is provided on the upper surface 82 of the main body 8, front and rear with respect to the direction in which the scour prevention mat 7 is fed out. Of the stoppers 12, the stopper 12a provided in front of the direction in which the scour prevention mat 7 is fed out is movable, and the stopper 12b provided in rear in the direction in which it is fed out is fixed. The movable stopper 12a can be released by storing it in the main body 8 so that it does not protrude from the upper surface 82.

[0024] The lateral guides 13 are positioned on both sides of the roller 9 along the direction in which the scour prevention mat 7 is fed out. The lateral guides 13 are, for example, multiple protrusions projecting from the upper surface 82 of the main body 8, guide rollers, or protrusions to which friction-reducing plates are attached, and are positioned at intervals in the direction in which the scour prevention mat 7 is fed out. The tip portion 14 is provided near the end of the main body 8 in the direction in which the scour prevention mat 7 is fed out. The tip portion 14 has a slope formed on its upper surface 82 such that it approaches the lower surface 81 as it moves forward from the main body 8, and may have a curve 83 at the end of the lower surface 81. The main body 8 may be manufactured as a single unit including the tip portion 14, or the part excluding the tip portion 14 and the tip portion 14 may be manufactured separately and joined on site.

[0025] Multiple rollers 9 are arranged on the main body 8, including the tip portion 14, so that their rotation axes are perpendicular to the direction in which the scour prevention mat 7 is fed out. Of the multiple rollers 9, at least some are drive rollers 9b capable of moving the scour prevention mat 7, and the others are free rollers 9a that are not for driving. As shown in Figure 1(b), it is desirable that the surface of the free rollers 9a be smooth, and the surface of the drive rollers 9b have irregularities to increase friction with the scour prevention mat 7. The diameter, number, arrangement of the rollers 9a and 9b, and the driving force of the rollers 9b can be appropriately determined according to the size and weight of the scour prevention mat 7 to be moved. It is also possible that all rollers 9 are drive rollers 9b, but it is desirable that the number of drive rollers 9b be small within the range in which the scour prevention mat 7 can be moved.

[0026] The lifting sections 10 are provided at multiple locations near the outer edge of the upper surface 82 of the main body 8. A wire 11 is connected to the lifting sections 10, and the wire 11 is hooked onto a lifting hook 17 of a lifting machine or the like.

[0027] As shown in Figure 2(a), the scour prevention mat 7 is, for example, an impermeable asphalt (hereinafter referred to as As) mat. The scour prevention mat 7 has an outer shape that is approximately octagonal, with a roughly circular hole 3 formed in the center. It is desirable that the scour prevention mat 7 be formed so that multiple outer edge holes 2 are located on a circle concentric with the hole 3 near the outer edge. As shown in Figure 2(b), the scour prevention mat 7 has a reinforcing net 6, such as a glass fiber tape mesh, placed between the lower As layer 4 and the upper As layer 5 as needed.

[0028] Furthermore, the outer shape of the scour prevention mat 7 is not limited to a polygon, and the holes 3 do not have to be approximately circular. Also, the outer edge holes 2 and holes 3 may not be formed on the scour prevention mat 7. The shape should be determined based on manufacturability, construction method, quality assurance, cost, etc. The scour prevention mat 7 is not limited to an asphalt mat, but may also be other mat-like materials or sheet-like materials, but it is particularly effective when the scour prevention mat 7 cannot be folded or rolled up.

[0029] The scour prevention mat 7 is placed on the main body 8 of the scour prevention mat laying device 1 in the yard on the work vessel. To place the scour prevention mat 7 on the main body 8, as shown in Figure 2(c), the work platform 22 on which the scour prevention mat 7 is placed is positioned at the front end of the main body 8, and the winch 24 is positioned at the rear end of the main body 8. Then, the stopper 12a is stored in the main body 8, the adjustment block 23 is placed on the tip 14 of the main body 8, the scour prevention mat 7 and the winch 24 are connected by a wire 25, and the wire 25 is wound up with the winch 24 to move the scour prevention mat 7 onto the main body 8. When moving the scour prevention mat 7, the movement may be assisted by the drive roller 9b.

[0030] The scour prevention mats 7 may be manufactured on land by stacking them on the workbench 22, or they may be manufactured elsewhere and placed on the workbench 22. The scour prevention mats 7 are lifted and moved onto the work vessel while placed on the workbench 22. When stacking multiple scour prevention mats 7 on the workbench 22, a fluororesin sheet 26 is placed between the scour prevention mats 7 to reduce friction. In addition, to eliminate the step when moving the scour prevention mats 7 from the workbench 22 onto the main body 8, the adjustment blocks 23 can be replaced as needed with ones of the appropriate height.

[0031] Figure 3 shows the method for laying the scour prevention mat 7. To lay the scour prevention mat 7 on the seabed 15 using the scour prevention mat laying device 1, first, the scour prevention mat 7 is placed on the main body 8 on the work vessel in the manner shown in Figure 2(c). Next, as shown in Figure 3(a), the stopper 12a is made to protrude from the upper surface of the main body 8, and with the scour prevention mat 7 placed in the area enclosed by the stoppers 12a, 12b and the side guide 13, the main body 8 is lifted with a lifting machine such as a crane and lowered into the water. Then, as shown in Figure 3(b), the main body 8 is lowered to the seabed 15, and the stopper 12a is retracted into the main body 8 to release it.

[0032] Once the stopper 12a is released, the main body 8 is tilted in the direction of feeding out the scour prevention mat 7, as shown in Figure 3(c), with the tip 14 facing downwards.

[0033] When the main body 8 is tilted, the main body 8 is moved backward while the scour prevention mat 7 is fed forward by the multiple rollers 9. At this time, of the multiple rollers 9, the drive roller 9b grips the scour prevention mat 7 with the irregularities on its surface and pulls it out in the feeding direction, while the free roller 9a assists in the feeding direction movement of the scour prevention mat 7 due to its own weight. The lateral guides 13 prevent the scour prevention mat 7, fed out by the multiple rollers 9, from shifting in the direction of movement. When the main body 8 is moved backward, the unevenness of the seabed 15 is leveled by the sled 83 on the lower surface 81, so that the scour prevention mat 7 is laid on a nearly flat seabed 15.

[0034] As shown in Figure 3(d), once the scouring prevention mat 7 has been laid on the seabed 15, the main body 8 is lifted up by the wire 11 and retrieved to the surface.

[0035] Thus, in the first embodiment, the scour prevention mat 7 is placed on the main body 8 and lowered to the seabed 15. This ensures that the scour prevention mat 7 does not bend or flex during lowering, and there is no concern about damage due to stress concentration near the suspension fittings partially embedded in the mat, thus ensuring its integrity. Furthermore, after lowering to the seabed 15, the main body 8 is tilted and moved backward while the scour prevention mat 7 is moved forward of the main body 8. This allows the main body 8 to settle on the seabed, positioning it for laying and enabling the scour prevention mat 7 to be laid on the seabed 15.

[0036] Hereinafter, another example of the present invention will be described as the second to sixth embodiments. The second to sixth embodiments will be described in terms of how they differ from the embodiments described so far, and similar components will be denoted by the same reference numerals in the figures, etc., and their descriptions will be omitted. Furthermore, the components described in each embodiment can be combined as needed.

[0037] [Second Embodiment] Figure 4 shows a scour prevention mat laying device 1a according to the second embodiment. The scour prevention mat laying device 1a of the second embodiment differs from the scour prevention mat laying device 1 of the first embodiment in that it has a wire position adjustment mechanism 16 and the main body 8a has a cavity 85 inside.

[0038] As shown in Figure 4(a), the scour prevention mat laying device 1a consists of a main body 8a, multiple rollers 9, a pulley 10a which is a lifting part for lifting the main body 8a, a wire position adjustment mechanism 16, etc. The main body 8a is the part on which the scour prevention mat 7 is placed. The main body 8a is a steel box that is roughly rectangular in plan view, and as shown in Figure 4(b), it has a cavity 85 inside, and the cavity 85 is divided by a partition wall 84 as needed for stress management, deformation suppression, etc. In the scour prevention mat laying device 1a, the direction in which the scour prevention mat 7 is fed out and the front of the main body 8a correspond to the right direction in Figure 4(a). In addition, although not shown, there may be normally open openings or openable / closable openings to allow sand that has entered through the gaps of the rollers 9 to escape from the bottom of the cavity 85, or to allow water to pass through while the main body 8a is lowered or raised.

[0039] The pulleys 10a are positioned near the outer edge of the upper surface 82 of the main body 8a, at the front and rear of the main body 8a, respectively, with respect to the direction in which the scour prevention mat 7 is fed out. The wire position adjustment mechanism 16 is positioned between the front and rear pulleys 10a of the main body 8a. The wire 11a is routed via the wire position adjustment mechanism 16 and the front and rear pulleys 10a of the main body 8a, and can be hooked onto the lifting hook 17 and lifted upward with a lifting machine or the like. The wire position adjustment mechanism 16 can move the wire 11a in the front-rear direction of the main body 8a or fix the position of the wire 11a.

[0040] Figure 5 shows the method for adjusting the position of the wire 11a. To lay the scour prevention mat 7 on the seabed 15 using the scour prevention mat laying device 1a, the scour prevention mat 7 is placed on the main body 8a in the same manner as in the first embodiment, and the main body 8a is lowered into the water by the wire 11a with the stopper 12a protruding from the upper surface of the main body 8a. At this time, the amount of ballast water in the cavity 85 separated by the partition wall 84 shown in Figure 4(b) can be adjusted with a pump or the like to control the balance between buoyancy and weight while lowering the main body 8a into the water. Once the main body 8a has settled on the seabed 15, the stopper 12a is retracted into the main body 8 and released.

[0041] After releasing the stopper 12a, the suspension hook 17 is lowered to loosen the wire 11a as shown in Figure 5(a). Next, with the wire 11a loosened, the suspension hook 17 is moved in the direction of arrow C1 in Figure 5(a) (opposite to the direction of movement of the scour prevention mat 7), and the wire 11a is moved forward between the front and rear pulleys 10a of the main body 8a by the wire position adjustment mechanism 16, as shown by the dotted line in Figure 5(b). After moving the suspension hook 17 to the position shown in Figure 5(b), the wire 11a is fixed in place. Since the suspension balance in the front-rear direction of the main body 8a has been changed by the adjustment of the wire 11a position by the wire position adjustment mechanism 16, when the suspension hook 17 is raised in the direction of arrow C2, the main body 8a tilts with the tip 14 side facing downwards, as shown in Figure 5(c). In this case, the amount of ballast water in the cavity 85 separated by the partition wall 84 may be adjusted with a pump or the like to assist in tilting the main body 8a to a predetermined angle while manipulating the balance between buoyancy and weight.

[0042] Once the main body 8a is tilted, the scouring prevention mat 7 is moved forward of the main body 8a by multiple rollers 9 while moving the main body 8a backward (in the direction of arrow C3 in the figure), similar to the first embodiment, thereby moving and laying the scouring prevention mat 7 from the main body 8a onto the seabed 15.

[0043] Even when the scour prevention mat 7 is laid on the seabed 15 using the scour prevention mat laying device 1a of the second embodiment, the soundness can be ensured, as in the first embodiment, by preventing bending or other deformation of the scour prevention mat 7 during suspension, and by eliminating concerns about damage due to stress concentration near the suspension fittings partially embedded in the mat. Furthermore, the scour prevention mat 7 can be easily positioned and laid on the seabed 15.

[0044] The scour prevention mat laying device 1a allows for easy adjustment of the tilt by changing the suspension balance of the main body 8a in the front-rear direction by moving the wire 11a between the front and rear pulleys 10a using the wire position adjustment mechanism 16. Furthermore, by fixing the position of the moved wire 11a with the wire position adjustment mechanism 16, the main body 8a can be maintained at a constant tilt. In this embodiment, the scour prevention mat is suspended in two rows, front and rear, in the laying direction, and its relative length is adjusted. However, although not shown in the figures, a wire or fiber rope winding and stopper mechanism may be used instead of the wire position adjustment mechanism 16. This makes it possible to support the weight of the main body 8a and the scour prevention mat 7 at more suspension points while allowing for length adjustment of the wire 11 at multiple points.

[0045] [Third Embodiment] Figure 6 shows a scour prevention mat laying device 1b according to the third embodiment. The scour prevention mat laying device 1b of the third embodiment differs from the scour prevention mat laying device 1 of the first embodiment in that holes 18 and gaps 19 are formed in the main body portion 8b that penetrate vertically.

[0046] As shown in Figures 6(a) and 6(b), the scour prevention mat laying device 1b consists of a main body 8b, a plurality of rollers 9, a suspension unit 10, etc. The main body 8b is the part on which the scour prevention mat 7 is placed. The main body 8b has a double steel frame 86 that is roughly rectangular in plan view, and a hole 18 that penetrates vertically is formed in the inner frame 86a, which is located approximately in the center of the part on which the scour prevention mat 7 is placed. The frames 86a and 86b are connected, for example, at the bottom. Some of the plurality of rollers 9 are attached to the outer frame 86b, and others are attached to the inner frame 86a and the outer frame 86b. In the main body 8b, gaps 19 that penetrate vertically are formed between the plurality of rollers 9 and, if necessary, at the bottom of the main body 8b.

[0047] To lay the scour prevention mat 7 on the seabed using the scour prevention mat laying device 1b, the scour prevention mat 7 is placed on the main body 8b in the same manner as in the first embodiment. At this time, the holes 3 of the scour prevention mat 7 shown in Figure 2 are aligned with the holes 18 of the main body 8b. Next, the main body 8b is lowered and sunk to the seabed. Since water can pass through the holes 3 and gaps 19 formed in the main body 8b, when it is lowered into the water, water escapes from below through the opening or holes 18 at the bottom of the main body 8b, reducing water resistance.

[0048] Subsequently, the main body 8b is tilted and moved backward while the scour prevention mat 7 is moved in front of the main body 8b by the roller 9 and laid on the seabed. At this time, the water flow generated by the movement of the main body 8b and the rotation of the roller 9 may stir up the sand on the seabed, but the sand passes through the gap 19 in the main body 8b along with the water.

[0049] Even when the scour prevention mat 7 is laid on the seabed 15 using the scour prevention mat laying device 1b of the third embodiment, the soundness can be ensured, as in the first embodiment, by preventing bending or other damage to the scour prevention mat 7 during suspension, and by eliminating concerns about damage due to stress concentration near the suspension fittings partially embedded in the mat. Furthermore, the scour prevention mat 7 can be easily positioned and laid on the seabed 15.

[0050] The scour prevention mat laying device 1b has holes 18 and gaps 19 formed in the main body 8b, so when the main body 8b is lowered underwater, water passes through the holes 18 and gaps 19, reducing water resistance on the underside of the main body 8b, which reduces the movement of the main body 8b and makes positioning easier. In addition, sand passes through the gaps 19 between the rollers 9, which prevents malfunction of the rollers 9 due to clogging.

[0051] [Fourth Embodiment] Figure 7 shows a scour prevention mat laying device 1c according to the fourth embodiment. The fourth embodiment differs from the scour prevention mat laying method of the first embodiment in that anchors are driven into the seabed when laying the scour prevention mat 7.

[0052] As shown in Figure 7, the scour prevention mat laying device 1c has an anchor pin 27 on the main body 8c that can be attached to the front end of the tip portion 14, and a retaining wire 28 is connected to the anchor pin 27. To lay the scour prevention mat 7 on the seabed using the scour prevention mat laying device 1c, the scour prevention mat 7 is placed on the main body 8c in the same manner as in the first embodiment. The scour prevention mat 7 is also connected to the anchor pin 27 via the retaining wire 28. At this time, the tip of the anchor pin 27 is facing the direction in which the scour prevention mat 7 is fed out, as shown in Figure 7(a).

[0053] Next, as shown in Figure 7(b), the main body 8c is lowered into the water. At this time, the anchor pin 27 is rotated by remotely operating a hydraulic jack or the like so that its tip faces downward as shown by arrow E. Then, when the main body 8c touches the bottom 15, the anchor pin 27 is driven into the bottom 15 by the weight of the main body 8c. After that, as shown in Figure 7(c), the anchor pin 27 is removed from the tip 14, the stopper 12a is released, the main body 8c is tilted, and while the main body 8c is moved backward, the scour prevention mat 7 is laid on the bottom of the water while being moved in front of the main body 8c by the roller 9.

[0054] Even when the scour prevention mat 7 is laid on the seabed 15 using the scour prevention mat laying device 1c of the fourth embodiment, similar to the first embodiment, no bending or other deformation occurs in the scour prevention mat 7 when it is suspended, and there is no concern about damage due to stress concentration near the suspension fittings partially embedded in the mat, thus ensuring its integrity. Furthermore, the scour prevention mat 7 can be easily positioned and laid on the seabed 15.

[0055] In the method for laying the scour prevention mat 7 of the fourth embodiment, the anchor pins 27 connected to the scour prevention mat 7 are fixed to the seabed 15. Therefore, when the main body 8c is moved backward while the scour prevention mat 7 is moved forward of the main body 8c, the scour prevention mat 7 is not dragged backward along with the main body 8c. Furthermore, it becomes possible to simplify the relative position adjustment between the backward movement of the main body 8c and the forward movement of the scour prevention mat 7.

[0056] Note that the anchors installed in the scour prevention mat laying device do not necessarily have to be at the front end of the tip section 14, and the anchors are not limited to anchor pins 27. Figures 8 and 9 show examples of scour prevention mat laying devices with different anchor positions and types.

[0057] The scour prevention mat laying device 1d shown in Figure 8(a) has a configuration almost identical to the scour prevention mat laying device 1c shown in Figure 8, but a slit 29 is formed in the main body 8d by cutting out the tip portion 14 from the front end, and an anchor pin 27 is detachably installed in the back of the slit 29. When using the scour prevention mat laying device 1d, the retaining wire 28 is shorter compared to when using the scour prevention mat laying device 1c, so the distance 35 shown in Figure 7(c) can be shortened.

[0058] The scour prevention mat laying device 1e shown in Figure 8(b) is provided with a cylindrical body 30 that penetrates the tip 14 vertically through the main body 8e, and a small-diameter pile 31, which serves as an anchor, is stored inside the cylindrical body 30. A retaining wire 28, one end of which is connected to the small-diameter pile 31, is positioned through a slit 29 from the lower end of the cylindrical body 30, and the other end is connected to the scour prevention mat 7. When laying the scour prevention mat 7 on the seabed with the scour prevention mat laying device 1e, for example, when the main body 8e is suspended in the water, the small-diameter pile 31 is made to protrude downward from the cylindrical body 30, and when the main body 8e reaches the bottom, the weight of the main body 8e drives the small-diameter pile 31 into the seabed. Alternatively, when the main body 8e is suspended in the water, the small-diameter pile 31 may be stored inside the cylindrical body 30, and after the main body 8e reaches the bottom, a hydraulic jack or the like may be remotely operated to drive the small-diameter pile 31 into the seabed.

[0059] The scour prevention mat laying device 1f shown in Figure 9 has a support guide 36 on the side of the tip 14f of the main body 8f, and a penetration bucket 32, which acts as an anchor, is detachably installed at the tip of the support guide 36. The penetration bucket 32 ​​is connected to a vacuum pump 34 via a tube 33. The scour prevention mat 7 is connected to the penetration bucket 32 ​​via a retaining wire 28. When laying the scour prevention mat 7 on the seabed with the scour prevention mat laying device 1f, after the main body 8f has settled on the seabed, the inside of the penetration bucket 32 ​​is forcibly drained by the vacuum pump 34 to penetrate the sandy ground of the seabed. A hydraulic jack or the like may also be provided as an auxiliary device. Once the penetration bucket 32 ​​has penetrated the seabed, the vacuum pump 34 is retrieved to the surface, the penetration bucket 32 ​​is removed from the support guide 36, and the main body 8f is tilted to lay the scour prevention mat 7 on the seabed. The vacuum pump 34 may also be attached to an ROV (Remotely operated vehicle: a wired, remotely controlled unmanned underwater vehicle), etc.

[0060] Even when using the scour prevention mat laying device shown in Figures 8 and 9, the same effects as in the fourth embodiment can be obtained by fixing the anchor pins 27, small-diameter piles 31, and penetration buckets 32 connected to the scour prevention mat 7 to the bottom of the water.

[0061] [Fifth Embodiment] Figure 10(a) shows a scour prevention mat laying device 1g according to the fifth embodiment. The scour prevention mat laying device 1g of the fifth embodiment differs from the scour prevention mat laying device 1 of the first embodiment in that the mat movement assisting device consists of a plurality of rollers 9 and a sliding plate 20.

[0062] The scour prevention mat laying device 1g has a main body 8g on which multiple rollers 9 and sliding plates 20 are arranged as a mat movement assist structure in at least a portion of the area where the scour prevention mat 7 is placed. The sliding plates 20 are arranged, for example, between the rollers 9 on the upper surface 82 of the main body 8g or on the outer surface of the free rollers 9a that are not used for driving. The sliding plates 20 are made of a material that has low friction with the scour prevention mat 7, such as fluororesin.

[0063] In the fifth embodiment, the use of a sliding plate 20 as a mat movement assist structure reduces friction between the main body 8g and the scouring prevention mat 7. Therefore, compared to the case where only multiple rollers 9 are used, it becomes easier to move the scouring prevention mat 7 further in the feeding direction when the main body 8g is tilted.

[0064] [Sixth Embodiment] Figure 10(b) shows a scour prevention mat laying device 1h according to the sixth embodiment. The scour prevention mat laying device 1h of the sixth embodiment differs from the scour prevention mat laying device 1 of the first embodiment in that the mat movement assisting device consists of a plurality of rollers 9 and nozzles 21.

[0065] The scour prevention mat laying device 1h has multiple rollers 9 and multiple nozzles 21 arranged in at least a portion of the area on the main body 8h where the scour prevention mat 7 is placed, as a mat movement assist structure. The multiple nozzles 21 spray seawater or seawater containing air upwards and in the direction of the feed-out of the scour prevention mat 7, as shown by the arrows in Figure 10(b), separating the upper surface 82 of the main body 8h from the scour prevention mat 7 and simultaneously promoting the movement of the scour prevention mat 7 in the feed-out direction. Air can be supplied by keeping an air tank inside the main body 8h or by supplying it from a work vessel at sea.

[0066] In the sixth embodiment, friction between the main body 8h and the scouring prevention mat 7 is reduced by using multiple nozzles 21 as a mat movement assist structure. Therefore, compared to the case where only multiple rollers 9 are used, it becomes easier to move the scouring prevention mat 7 further in the feeding direction when the main body 8h is tilted.

[0067] In the fifth and sixth embodiments, a sliding plate 20, a nozzle 21, and multiple rollers 9 were used in combination as a mat movement assist structure. However, these mat movement assist structures may be used individually or in combination. This also makes it possible to reduce the tilt of the main body 8 when sending out the scouring prevention mat 1.

[0068] In the first to sixth embodiments, each roller 9 is arranged continuously in a direction perpendicular to the direction in which the scour prevention mat 7 is fed out. However, the rollers 9 only need to be arranged to assist in the movement of the scour prevention mat 7 in the feeding direction. Furthermore, the guide members arranged along the feeding direction of the scour prevention mat 7 are not limited to the lateral guides 13. For example, in the scour prevention mat laying device 1i shown in Figure 10(c), the rollers 9a and 9b are arranged discontinuously in a direction perpendicular to the direction in which the scour prevention mat 7 is fed out. In addition, a lateral roller 13a is provided as a guide member.

[0069] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but the present invention is not limited to these examples. It will be obvious to those skilled in the art that various modifications or alterations can be conceived within the scope of the technical idea disclosed herein, and these will naturally also fall within the technical scope of the present invention.

[0070] For example, wheels or the like may be provided instead of the skid 83 on the lower surface 81 of the tip 14. Also, the lower surface 81 of the main body may be shaped like a downward convex curve in the direction in which the scour prevention mat is fed out, or like a downward convex curve in a direction perpendicular to the feeding direction. If the lower surface 81 is shaped like a downward convex curve, water resistance can be reduced when the main body is lowered into the water by allowing water to flow from the center outwards. Furthermore, fiber rope may be used instead of wire. [Explanation of symbols]

[0071] 1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i... Scrub prevention mat laying device 2………Outer pore 3, 18……hole 4……As lower layer 5……As upper layer 6… Reinforcement net 7. Scrap prevention mat 8, 8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h, 8i... Main body 9, 9a, 9b... Laura 10... Hanging section 10a... Pulley 11, 11a, 25… wire 12, 12a, 12b... Stopper 13... Lateral guide 13a... Side roller 14……Tip 15……Underwater 16…Wire position adjustment mechanism 17... Hanging hook 19... Gap 20... Sliding plate 21…Nozzle 22...Workbench 23... Adjustment piece 24...Winch 26… Fluororesin sheet 27... Anchor pin 28... Retaining wire 29... Slit 30……Cylinder 31……Small diameter pile 32………Penetration Bucket 33... Tube 34... Vacuum pump 35……distance 36…Support Guide 81……Bottom surface 82……Top surface 83...Sled 84……Bulkhead 85……Cavity 86, 86a, 86b……frame body

Claims

1. A device for laying erosion prevention mats on the seabed, The main body on which the erosion prevention mat is placed, The upper part of the main body includes a mat movement assist structure for moving the scouring prevention mat in the direction of discharge, A lifting section for lifting the main body, Equipped with With the erosion prevention mat placed on the main body and suspended from the bottom of the water, the main body is tilted toward the sending direction, and the erosion prevention mat can be moved from the main body to the bottom of the water by the mat movement assist structure, thereby enabling the erosion prevention mat to be laid on the bottom of the water. Scrap prevention mat laying device characterized in that, in the main body, a plurality of nozzles directed upward and outward are arranged in at least a part of the area on which the scouring prevention mat is placed as a mat movement assist structure, and friction between the main body and the scouring prevention mat is reduced by ejecting seawater or seawater containing air from the plurality of nozzles.

2. A device for laying erosion prevention mats on the seabed, The main body on which the erosion prevention mat is placed, The upper part of the main body includes a mat movement assist structure for moving the scouring prevention mat in the direction of discharge, A lifting section for lifting the main body, Equipped with With the erosion prevention mat placed on the main body and suspended from the bottom of the water, the main body is tilted toward the sending direction, and the erosion prevention mat can be moved from the main body to the bottom of the water by the mat movement assist structure, thereby enabling the erosion prevention mat to be laid on the bottom of the water. The scour prevention mat laying device is characterized in that, in the main body, a plurality of rollers are arranged as a mat movement assist structure in the area where the scour prevention mat is placed, and gaps are formed between the rollers that penetrate vertically and allow water and sand to pass through.

3. A device for laying erosion prevention mats on the seabed, The main body on which the erosion prevention mat is placed, The upper part of the main body includes a mat movement assist structure for moving the scouring prevention mat in the direction of discharge, A lifting section for lifting the main body, Equipped with With the erosion prevention mat placed on the main body and suspended from the bottom of the water, the main body is tilted toward the sending direction, and the erosion prevention mat can be moved from the main body to the bottom of the water by the mat movement assist structure, thereby enabling the erosion prevention mat to be laid on the bottom of the water. The scour prevention mat laying device is characterized in that, in the main body, a hole is formed approximately in the center of the area where the scour prevention mat is placed, which penetrates vertically and allows water to pass through.

4. A device for laying erosion prevention mats on the seabed, The main body on which the erosion prevention mat is placed, The upper part of the main body includes a mat movement assist structure for moving the scouring prevention mat in the direction of discharge, A lifting section for lifting the main body, Equipped with With the erosion prevention mat placed on the main body and suspended from the bottom of the water, the main body is tilted toward the sending direction, and the erosion prevention mat can be moved from the main body to the bottom of the water by the mat movement assist structure, thereby enabling the erosion prevention mat to be laid on the bottom of the water. The main body includes stoppers provided at the front and rear in the direction in which the scouring prevention mat is fed out, and guide members arranged on both sides in the direction in which the scouring prevention mat is fed out. A scour prevention mat laying device characterized by having a movable stopper located in front of the direction in which the scour prevention mat is fed out, and the stopper being able to be released after the mat has reached the bottom.

5. A device for laying erosion prevention mats on the seabed, The main body on which the erosion prevention mat is placed, The upper part of the main body includes a mat movement assist structure for moving the scouring prevention mat in the direction of discharge, A lifting section for lifting the main body, Equipped with With the erosion prevention mat placed on the main body and suspended from the bottom of the water, the main body is tilted toward the sending direction, and the erosion prevention mat can be moved from the main body to the bottom of the water by the mat movement assist structure, thereby enabling the erosion prevention mat to be laid on the bottom of the water. The aforementioned suspension section is a pulley, positioned at the front and rear of the main body with respect to the direction in which the scour prevention mat is fed out, and has a wire position adjustment mechanism between the front and rear pulleys for moving and fixing the wire. A scour prevention mat laying device characterized in that it is possible to lift the wire, which is routed via the wire position adjustment mechanism and the front and rear pulleys, upward, and that the suspension balance in the front and rear direction can be changed by moving the wire between the front and rear pulleys using the wire position adjustment mechanism while the wire is loosened.

6. A device for laying erosion prevention mats on the seabed, The main body on which the erosion prevention mat is placed, The upper part of the main body includes a mat movement assist structure for moving the scouring prevention mat in the direction of discharge, A lifting section for lifting the main body, Equipped with With the erosion prevention mat placed on the main body and suspended from the bottom of the water, the main body is tilted toward the sending direction, and the erosion prevention mat can be moved from the main body to the bottom of the water by the mat movement assist structure, thereby enabling the erosion prevention mat to be laid on the bottom of the water. The scour prevention mat laying device is characterized in that the main body has a tip portion near the end in the direction of feeding out the scour prevention mat, with a slope formed on the upper surface that approaches the lower surface towards the tip.

7. The scour prevention mat laying device according to any one of claims 1 to 6, characterized in that, in the main body, a plurality of rollers are arranged in at least a part of the area on which the scour prevention mat is placed as a mat movement assist structure, and at least a portion of the rollers are drive rollers, and the scour prevention mat can be moved by the drive rollers.

8. The scour prevention mat laying device according to any one of claims 1 to 6, characterized in that, in the main body, a sliding plate for reducing friction is arranged in at least a part of the area on which the scour prevention mat is placed as a mat movement assist structure.

9. A method for laying an erosion prevention mat using an erosion prevention mat laying device, The aforementioned scour prevention mat laying device is A device for laying erosion prevention mats on the seabed, The main body on which the erosion prevention mat is placed, The upper part of the main body includes a mat movement assist structure for moving the scouring prevention mat in the direction of discharge, A lifting section for lifting the main body, It is equipped with, This is a scour prevention mat laying device in which, with the scour prevention mat placed on the main body and suspended from the bottom of the water, the main body is tilted in the direction of sending out, and the scour prevention mat is moved from the main body to the bottom of the water by the mat movement assist structure, thereby enabling the scour prevention mat to be laid on the bottom of the water. Step a involves placing a scour prevention mat on the main body, Step b of lowering the main body to the bottom of the water, Step c involves tilting the main body and moving the main body backward while laying the erosion prevention mat in front of the main body on the seabed, A method for laying a scour prevention mat, characterized by comprising the following:

10. The method for laying an erosion prevention mat according to claim 9, characterized in that, before step c, anchors connected to the erosion prevention mat are driven into the seabed.

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