Rubble dumping device

Abstract

To provide a rubble dumping device capable of stabilizing an attitude of a bucket, holding its position even under a fast tidal current, and discharging rubble in a substantially uniform layer thickness.SOLUTION: A rubble dumping device comprises a bucket 3 that stores a large amount of rubble. The bucket 3 is provided on its outer periphery with a pair of curved protrusions 5L, 5R that are curved so as to protrude outward in a plan view. This makes it possible to stabilize an attitude of the bucket 3 and maintain its position even in a sea area with a fast tidal current, and also to discharge the rubble in a substantially uniform layer thickness.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a riprap dumping device that dumps protective riprap (crushed rock) onto, for example, a submarine cable laid on the seabed. [Background technology]

[0002] Generally, the first method of riprap covering, in which riprap (crushed rock) is dumped onto an existing submarine cable, is to use a grab bucket to grab the riprap and lower it to the seabed, then open the bucket above the submarine cable and dump the riprap onto the cable.The second method is to extend a tremie pipe to the seabed and dump the riprap into the tremie pipe, thereby dumping the riprap onto the submarine cable.

[0003] However, with the first construction method mentioned above, the amount of riprap thrown onto the cable in one cycle (from the start of lowering the grab bucket to the seabed, through the dumping of riprap, to the completion of raising the grab bucket) was small, which resulted in low construction efficiency and a long construction period. On the other hand, with the second construction method mentioned above, which is the riprap covering method using tremie pipes, it was difficult to accurately position the tremie pipes on the submarine cable due to the influence of tidal currents, and construction accuracy was an issue. There was also a risk of damage to the tremie pipes that were extended to the seabed due to their swinging.

[0004] As a conventional technology that addresses these issues, Patent Document 1 discloses a rubble dumping device that includes a box-shaped bucket into which rubble is dumped, a movable plate that is provided within the bucket and divides the interior of the bucket horizontally, a fixed plate that is provided within the bucket and divides the space defined by the movable plate into adjacent chambers lined up side by side, and a drive mechanism that drives the movable plate in an up and down direction, wherein the lower end of each chamber is closed by the movable plate, and the lower end of each chamber is opened sequentially as the drive mechanism raises the movable plate from its lower end position to its upper end position. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-12605 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, the sea area where riprap is dumped onto the undersea cable may have a fast tidal current (3 kt), and with the riprap dumping device described in Patent Document 1 mentioned above, the bucket yawing occurs due to the influence of the tidal current, and the bucket cannot stably maintain its position under the tidal current, making it impossible to accurately dump the riprap at the target position, and these problems need to be improved. Moreover, with the riprap dumping device described in Patent Document 1, when dumping the riprap, the riprap accumulates locally and cannot be spread out in a uniform layer thickness, and this also needs to be improved.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a rubble dumping device that can stabilize the attitude of a bucket that stores rubble and maintain its position even in fast currents, and can also scatter rubble in a substantially uniform layer thickness. [Means for solving the problem]

[0008] As a means for solving the above problem, the invention described in claim 1 is a rubble dumping device for dumping rubble onto the seabed, which is characterized by having a bucket that can accommodate a large number of rubble, and the bucket has a curved convex portion provided on its outer periphery that is curved so as to protrude outward in a planar view.

[0009] The invention as set forth in claim 2 is characterized in that in the invention as set forth in claim 1, the curved convex portions are arranged in pair so as to face each other.

[0010] The invention as set forth in claim 3 is characterized in that in the invention as set forth in claim 1, the outer surface of the curved convex portion is formed into a circular arc surface or an elliptical arc surface.

[0011] The invention as set forth in claim 4 is characterized in that in the invention as set forth in claim 1, the curved convex portion is configured in a cylindrical or elliptical cylindrical shape so as to surround the bucket.

[0012] The invention described in claim 5 is the invention described in claim 1, characterized in that the bucket is provided with a dispersion throwing means provided at its bottom for dispersing the rubble to be thrown onto the seabed, and the dispersion throwing means has multiple dispersion shafts arranged at intervals along the horizontal direction in multiple stages spaced apart along the vertical direction, and each dispersion shaft adjacent to the top and bottom is arranged so as not to overlap in a plan view.

[0013] The invention as set forth in claim 6 is characterized in that in the invention as set forth in claim 5, the dispersion shaft is formed in an inverted V shape when viewed from the front. [Effects of the Invention]

[0014] The rubble dumping device of the present invention can stabilize the attitude of the bucket and maintain its position even in fast currents, and can also scatter rubble in a substantially uniform layer thickness. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a front view of a bucket of a rubble dumping device according to this embodiment. [Figure 2] FIG. 2 is a front view showing the internal configuration of the bucket of the rubble dumping device according to this embodiment. [Figure 3] FIG. 3 is a front view for explaining the chambers in the bucket of the rubble dumping device according to this embodiment, in which a large number of rubble stones are stored. [Figure 4] FIG. 4 is a plan view of the bucket of the rubble dumping device according to this embodiment. [Figure 5] FIG. 5 is a right side view of the bucket of the rubble dumping device according to this embodiment. [Figure 6]FIG. 6 is a schematic perspective view of the bucket of the rubble dumping device according to this embodiment. [Figure 7] FIG. 7 shows the construction status and equipment when the rubble covering method is applied. [Figure 8] FIG. 8 is a schematic plan view of a bucket according to another embodiment. [Figure 9] FIG. 9 is a schematic plan view of a bucket according to yet another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. With reference to Fig. 7, a riprap dumping device 1 according to an embodiment of the present invention is applied to a riprap covering method for laying a large number of ripraps 2 (crushed rock) on a submarine cable 70 (submarine power transmission cable, communication cable, etc.) laid on the seabed 60. Here, plane V1 in Fig. 4 is a plane of symmetry (hereinafter referred to as "vertical plane V1") that divides the inside of the bucket body 4, which will be described later, symmetrically from side to side. Plane V2 in Fig. 4 is a plane of symmetry (hereinafter referred to as "vertical plane V2") that divides the inside of the bucket body 4 symmetrically from front to back.

[0017] 1, 2 and 7, the riprap dumping device 1 according to this embodiment comprises a bucket 3 for accommodating a large number of ripraps 2, and a lifting device (not shown) for raising and lowering a pair of movable plates 17L, 17R of the bucket 3. Referring to Figs. 1 and 2, the bucket 3 comprises a bucket body 4 for accommodating a large number of ripraps 2, a pair of curved convex portions 5L, 5R provided at both left and right ends of the bucket body 4 for accommodating the ripraps 2 in cooperation with the bucket body 4, and a dispersing and dumping means 6 provided below the bucket body 4 for dispersing the ripraps 2 dumped from the bucket body 4 onto the seabed and scattering them in a substantially uniform layer thickness.

[0018] The bucket body 4 has a rectangular parallelepiped frame structure 4A (frame structure) made of steel materials such as angle bars, pipes, and flat bars. Referring to Figures 1 and 4, the front and rear walls 13 and 14 of the bucket body 4, facing the first chambers 31L and 31R, the second chambers 32L and 32R, and the third chambers 33L and 33R (described later), are fitted with expanded metal to prevent the riprap 2 in the first chambers 31L and 31R, the second chambers 32L and 32R, and the third chambers 33L and 33R from leaking out through gaps in the frame structure 4A and to allow the riprap 2 to be viewed from the outside. Referring to Figures 1, 2, and 5, legs 11, 11 are provided at the four corners of the bottom of the bucket body 4 to support the bucket body 4 at a certain height above the ground (the deck of a ship 65, the seabed 60, etc.).

[0019] 1 to 4, a pair of curved protrusions 5L, 5R are provided at both left and right ends of the bucket body 4. The curved protrusions 5L, 5R protrude outward. The curved protrusions 5L, 5R are formed by bending a thin plate material at a predetermined curvature in a plan view. The outer and inner surfaces of the curved protrusions 5L, 5R are formed as arcuate surfaces in a plan view. The curved protrusions 5L, 5R extend from the upper end to the lower end (the base of the leg portions 11) of the bucket body 4. The curved protrusions 5L, 5R protrude outward from approximately the entire length of one shorter side of the bucket body 4. In other words, both circumferential ends of the curved protrusions 5L, 5R are connected to both front and rear ends of the left and right ends of the bucket body 4, respectively. Third chambers 33L, 33R, which will be described later, are formed inside the curved protrusions 5L, 5R. The third chambers 33L, 33R inside the curved convex portions 5L, 5R also accommodate riprap 2. In this embodiment, the curved convex portions 5L, 5R are provided in the range from the upper end to the lower end of the bucket body 4, but they may also be provided in the range from the upper end of the bucket body 4 to the lower end of the leg 11. Also, the right curved convex portion 5R is not shown in Figure 6.

[0020] 2 to 4, a pair of movable plates 17L, 17R are provided inside the bucket body 4, spaced apart in the left-right direction and facing each other. The movable plates 17L, 17R are symmetrical with respect to a vertical plane V1 (see FIG. 4). The movable plates 17L, 17R are parallel to the vertical plane V1. The movable plates 17L, 17R have vertically extending edge portions on both the left and right sides, which are guided by pairs of guide rollers 15, 15 provided on the front wall 13 and rear wall 14 of the bucket body 4, allowing them to move up and down.

[0021] The upper ends of the movable plates 17L, 17R are provided with protrusions 19L, 19R (see FIGS. 4 and 6) that protrude forward and backward. The movable plates 17L, 17R are suspended (hanging) by the frame structure 4A with the protrusions 19L, 19R hooked onto the opening periphery 8 (see FIGS. 4 and 6) on the upper end side of the bucket body 4. Referring to FIGS. 1 and 6, guide shafts 21L, 21R extend upward from the upper end of the bucket body 4. The guide shafts 21L, 21R have guide grooves 22L, 22R that guide the pair of protrusions 19L, 19R of the movable plates 17L, 17R in the up-down direction. The guide shafts 21L, 21R are firmly held in position by reinforcing shafts 24L, 24R. The movable plates 17L and 17R are supported so as to be movable up and down (movable up and down) along the guide shafts 21L and 21R.

[0022] 2, 4, and 6, brackets 26L, 26R are provided at the center in the front-to-rear direction of the upper ends of the movable plates 17L, 17R. One ends of wire ropes 30L, 30R (see FIG. 7) are connected to the brackets 26L, 26R. The other ends of the wire ropes 30L, 30R are wound up or unwound by a lifting device provided on a crane 66 on a ship 65, thereby raising or lowering the movable plates 17L, 17R.

[0023] 3, a partition wall 35L is provided between the movable plate 17L and the curved convex portion 5L on the left side of the bucket body 4. The partition wall 35L divides the space between the movable plate 17L and the curved convex portion 5L into an outer (left) first chamber 31L and an inner (right) second chamber 32L. The partition wall 35L includes a vertical plate 36L disposed parallel to the movable plate 17L and an inclined plate 37L extending from the lower edge of the vertical plate 36L to the movable plate 17L at a predetermined angle (45° with respect to the vertical direction in this embodiment). As a result, the second chamber 32L is defined within the bucket body 4 by the movable plate 17L, the partition wall 35L, the front wall 13, and the rear wall 14.

[0024] An inclined plate 39L is provided within the bucket body 4, below the partition wall 35L, and parallel to the inclined plate 37L. That is, the inclined plate 39L is inclined at a predetermined angle (45° with respect to the vertical in this embodiment). The inclined plate 39L extends from the curved convex portion 5L of the bucket body 4 to the lower end of the movable plate 17L. As a result, a first chamber 31L is defined within the bucket body 4 by the curved convex portion 5L, the partition wall 35L, the inclined plate 39L, the front wall 13, and the rear wall 14. Note that, with reference to FIG. 6, a plurality of reinforcing ribs 40R are provided between the lower surface of the inclined plate 39R of the bucket 3 and the inner surface of the curved convex portion 5R (not shown in FIG. 6) and spaced apart in the front-rear direction. Similarly, a plurality of reinforcing ribs (not shown) are provided between the lower surface of the inclined plate 39L of the bucket 3 and the inner surface of the curved convex portion 5L and spaced apart in the front-rear direction.

[0025] 3, a central partition wall 41 is provided in the center between the pair of movable plates 17L, 17R. The central partition wall 41 has a vertical plate 42 that is parallel to the movable plates 17L, 17R, and an inclined plate 43L that extends from the lower edge of the vertical plate 42 at a predetermined angle (45° with respect to the vertical direction in this embodiment) to the movable plate 17L. Thus, a third chamber 33L is defined within the bucket body 4 by the movable plate 17L, the central partition wall 41, the front wall 13, and the rear wall 14. The central partition wall 41 also has an inclined plate 43R that extends from the lower edge of the vertical plate 42 at a predetermined angle (45° with respect to the vertical direction in this embodiment) to the movable plate 17R. That is, the cross section of the central partition wall 41 is formed in an inverted Y shape by the vertical plane V2. As explained above, it is preferable that the internal volumes of the first chamber 31L, the second chamber 32L, and the third chamber 33L are approximately the same.

[0026] The bucket body 4 is configured to be symmetrical with respect to the vertical plane V1. Therefore, the configuration on the right side of the vertical plane V1 in the bucket body 4 will only be given reference numerals corresponding to those in the drawings, and redundant explanations will be omitted.

[0027] 1, 2, 5, and 6, a distribution throwing means 6 is provided below the bucket 3, i.e., below the bucket body 4. The distribution throwing means 6 will be described below. Two front upper and front lower support shafts 50U, 50D are provided at a distance in the vertical direction in the bucket body 4 so as to span the front pair of legs 11, 11. Meanwhile, two rear upper and rear lower support shafts (not shown) are provided at positions corresponding to the front upper and front lower support shafts 50U, 50D so as to span the rear pair of legs 11, 11. Furthermore, upper distribution shafts 52U, 52U are provided so as to span between the front upper support shaft 50U and the rear upper support shaft. A plurality of upper distribution shafts 52U, 52U are provided at equal intervals in the left-right direction. In this embodiment, a total of three upper distribution shafts 52U are arranged, with one upper distribution shaft 52U being arranged approximately in the center of the bucket body 4 in the left-right direction, and two upper distribution shafts 52U, 52U being arranged equally spaced on both sides of this upper distribution shaft 52U in the left-right direction.

[0028] Meanwhile, lower distribution shafts 52D, 52D are provided to bridge between the front lower support shaft 50D and the rear lower support shaft. A plurality of lower distribution shafts 52D, 52D are provided at equal intervals along the left-right direction. Each lower distribution shaft 52D, 52D is positioned so as not to overlap with each upper distribution shaft 52U, 52U in a plan view. In this embodiment, a total of four lower distribution shafts 52D, 52D are provided, and the two lower distribution shafts 52D, 52D near the left-right center of the bucket body 4 are positioned in the center between the two adjacent upper distribution shafts 52U, 52U. Meanwhile, the two lower distribution shafts 52D, 52D at both ends in the left-right direction are positioned in the center between the adjacent upper distribution shaft 52U and the leg 11.

[0029] The distance (pitch) between adjacent upper distribution shafts 52U, 52U is the same as the distance (pitch) between adjacent lower distribution shafts 52D, 52D. Referring to Fig. 2, the upper and lower distribution shafts 52U, 52D are angle members formed in an inverted V shape when viewed from the front. The upper and lower distribution shafts 52U, 52D may be triangular with their apexes facing upward when viewed from the front, or may be circular when viewed from the front, and the shape when viewed from the front is not limited.

[0030] Although not shown, the frame structure 4A of the bucket body 4 is provided with a transponder, multiple underwater lights that illuminate the seabed 60, multiple underwater cameras, an accelerometer / inclinometer (motion sensor, etc.), etc. The transponder provides (transmits a signal) information on the position, course, speed, etc. of the bucket 3 to a receiving device (not shown) installed on the ship 65 (see FIG. 7). The image signal of the underwater camera is output as an image to a monitoring system installed on the ship 65 (see FIG. 7). Furthermore, when the riprap 2 is dumped onto the seabed, the vibration of the bucket 3 that occurs when the riprap 2 in the bucket body 4 passes through the dispersing dumping means 6 is detected by the accelerometer / inclinometer, and the detection signal is output to the monitoring system installed on the ship 65.

[0031] 6 and 7, brackets 54, 54 are provided on the upper end of frame structure 4A of bucket body 4 at the four corners and at the center of both left and right ends (center in the front-rear direction). One end of a plurality of wire ropes 55 is connected to each of these brackets 54, 54. The bucket 3 is lowered by paying out the other end of each wire rope 55 with a lifting device provided on a crane 66 on a ship 65, and the bucket 3 is raised by reeling in the other end of the wire rope 55 with the lifting device.

[0032] Next, the construction procedure for throwing riprap 2 (crushed rock) onto the submarine cable 70 laid on the seabed 60 using the riprap dumping device 1 described above will be described with reference to Figs. 1 to 3, 7, etc. 7, a ship 65 that performs construction work in the sea area at the site is equipped with a crane 66. The ship 65 also carries a required amount (for example, a two-day supply) of riprap 2, a wheel loader 67, and a backhoe 68.

[0033] First, a backhoe 68 dumps riprap 2 into the first chambers 31L, 31R, second chambers 32L, 32R, and third chambers 33L, 33R of a bucket 3 placed on the deck of a ship 65. Next, a crane 66 hoists the bucket 3, and a lifting device (not shown) mounted on the crane 66 pays out the wire rope 55 to sink the bucket 3 to the seabed 60. Then, using monitoring means such as a transponder, an underwater camera, or an ROV 69 (Remote Operated Vehicle), the bucket 3 is positioned at a first position on a submarine cable 70 on the seabed 60. Note that the legs 11 of the bucket 3 may be left floating rather than touching the seabed 60.

[0034] Next, while checking the situation using monitoring means such as an underwater camera or ROV 69, the wire ropes 30L, 30R are reeled in by the lifting device mounted on the crane 66 to raise the movable plates 17L, 17R to a certain height, and the riprap dumping ports 45L, 45R (see Figure 3) of the first chambers 31L, 31R of the bucket 3 are opened. In other words, the movable plates 17L, 17R are raised until their lower ends are positioned at the lower ends of the inclined plates 37L, 37R, and the riprap dumping ports 45L, 45R (see Figure 3) of the first chambers 31L, 31R of the bucket 3 are opened. As a result, the riprap 2 in the first chambers 31L, 31R is dumped from the riprap dumping ports 45L, 45R onto the submarine cable 70 via the distribution dumping means 6.

[0035] At this time, the riprap 2 from the riprap inlets 45L, 45R passes through the dispersing and throwing means 6, so that it is dispersed over a wide area and thrown out in a generally uniform layer thickness, rather than being thrown out in a locally high layer thickness onto the submarine cable 70. Furthermore, when the riprap 2 from the riprap inlets 45L, 45R passes through the dispersing and throwing means 6, vibrations occur in the bucket 3. These vibrations are detected by an accelerometer / inclinometer installed in the bucket 3, and the operator on board the crane 66 and the crew of the ship 65 can grasp the passage information of the riprap 2 based on this detection through a monitoring system. After throwing is complete, the wire ropes 30L, 30R are let out by the lifting device, and the movable plates 17L, 17R are lowered to their bottom end positions.

[0036] Next, while checking the situation using monitoring means such as an underwater camera or ROV 69, the crane 66 is operated to position the bucket 3 at the second position. Here, the bucket 3 positioned at the second position is positioned so as to overlap the bucket 3 positioned at the first position by a certain length (for example, 0.5 m).

[0037] Next, while checking the situation using monitoring means such as an underwater camera or ROV 69, the wire ropes 30L, 30R are reeled in by the lifting device mounted on the crane 66 to raise the movable plates 17L, 17R to a certain height, thereby opening the riprap dumping ports 46L, 46R (see Figure 3) in the second chambers 32L, 32R of the bucket 3. In other words, the movable plates 17L, 17R are raised until their lower ends are positioned at the lower ends of the inclined plates 43L, 43R, thereby opening the riprap dumping ports 46L, 46R in the second chambers 32L, 32R of the bucket 3. As a result, the riprap 2 in the second chambers 32L, 32R is dumped onto the submarine cable 70 through the riprap dumping ports 46L, 46R.

[0038] At this time, the riprap 2 from the riprap dumping ports 46L, 46R also passes through the dispersing and throwing means 6, causing it to be dispersed over a wide area on the submarine cable 70 and thrown out in a roughly uniform layer thickness. Also, when the riprap 2 from the riprap dumping ports 46L, 46R passes through the dispersing and throwing means 6, the vibrations of the bucket 3 are detected by the accelerometer / inclinometer, and the passing information of the riprap 2 based on this detection can be grasped by the operator on board the crane 66 and the crew of the ship 65 using the monitoring system. After dumping is complete, the wire ropes 30L, 30R are let out by the lifting device to pull down the movable plates 17L, 17R to their bottom end positions.

[0039] Next, while checking the situation using monitoring means such as an underwater camera or ROV 69, the crane 66 is operated to position the bucket 3 at the third position. Here, the bucket 3 positioned at the third position is positioned so as to overlap the bucket 3 positioned at the second position by a certain length (for example, 0.5 m).

[0040] Next, while monitoring the situation using monitoring means such as an underwater camera or ROV 69, the lifting device mounted on the crane 66 reels in the wire ropes 30L, 30R to raise the movable plates 17L, 17R to their upper end positions. This opens the third chambers 33L, 33R of the bucket 3 at a predetermined height from the lower edges of the inclined plates 43L, 43R. As a result, the riprap 2 in the third chambers 33L, 33R passes through the second chambers 32L, 32R, the riprap 2 from the riprap sacks 46L, 46R of the second chambers 32L, 32R, and the dispersing and throwing means 6 onto the submarine cable 70. At this time, the riprap 2 from the riprap sacks 46L, 46R passes through the dispersing and throwing means 6 and is dispersed over a wide area on the submarine cable 70, and is scattered in a substantially uniform layer thickness. In addition, when the rubble 2 from the rubble inlets 46L and 46R passes through the dispersing means 6, the vibration of the bucket 3 is detected by an accelerometer / inclinometer, and the operator on board the crane 66 and the crew of the ship 65 can grasp the passing information of the rubble 2 based on this detection through the monitoring system.

[0041] The bucket 3 of the riprap dumping device 1 according to this embodiment is provided with a pair of curved protrusions 5L and 5R. Therefore, as described above, the bucket 3 can be stabilized and maintained in position even in a fast current while the bucket 3 is submerged in the seabed 60 and the submarine cable 70 is being covered with riprap 2, even in a sea area with a fast current. When a cylindrical or prismatic body is placed in a water current, vortex streets known as Karman vortices are generated alternately behind it. These vortices have an exciting force, causing the cylindrical or prismatic body placed in the water current to vibrate. On the other hand, prismatic bodies are more susceptible to vortex separation than cylindrical bodies, and therefore have a greater exciting force. Furthermore, by eliminating corners and providing a pair of curved protrusions 5L and 5R in the bucket 3, the generation of vortices can be suppressed, ensuring the stability of the bucket 3's position in the water current.

[0042] After the dropping is complete, the wire ropes 30L, 30R are paid out by the lifting device to lower the movable plates 17L, 17R to their bottom end positions, and then the wire ropes 55 are reeled in by the lifting device mounted on the crane 66 to pull the bucket 3 up from the seabed 60. The bucket 3 pulled up from the seabed 60 is placed on the deck of the ship 65 by the crane 66, and the backhoe 68 again drops the riprap 2 into the now empty first chambers 31L, 31R, second chambers 32L, 32R, and third chambers 33L, 33R of the bucket 3. Thereafter, the above-mentioned covering work of the submarine cable 70 is repeated.

[0043] As described above, the riprap dumping device 1 according to this embodiment includes a bucket 3 that can accommodate a large number of ripraps 2, and the bucket 3 includes a pair of curved protrusions 5L, 5R that are provided on its outer periphery facing each other. This allows the bucket 3 to stabilize its posture and maintain its position when the bucket 3 is sunk into the seabed 60 and the ripraps 2 are dumped into a predetermined location, i.e., when the submarine cable 70 is covered with the ripraps 2, even in a fast current in the field. In other words, the pair of curved protrusions 5L, 5R can suppress the bucket 3 from tilting or swaying (yawing) relative to the vertical direction, even in a fast current. The adoption of the riprap dumping device 1 according to this embodiment significantly improves work efficiency, thereby significantly shortening the construction period and providing the best riprap covering method.

[0044] The riprap dumping device 1 according to this embodiment is also provided with a dispersing means 6 below the bucket 3 for dispersing the riprap 2 to be dumped onto the seabed. The dispersing means 6 comprises a plurality of upper dispersion shafts 52U, 52U spaced equally apart horizontally (left-right), and a plurality of lower dispersion shafts 52D, 52D spaced equally apart horizontally (left-right), spaced apart vertically. The upper dispersion shafts 52U, 52U and the lower dispersion shafts 52D, 52D are arranged so as not to overlap in a plan view. The dispersing means 6 disperses the riprap 2 dumped from the riprap inlets 45L, 45R and the riprap inlets 46L, 46R of the bucket body 4 over a wide area, allowing it to be discharged in a substantially uniform layer thickness.

[0045] In the bucket 3 of the rubble dumping device 1 according to this embodiment, the outer surfaces (and inner surfaces) of the pair of curved protrusions 5L, 5R are formed into arcuate surfaces, but they may also be formed into elliptical arcuate surfaces. As another embodiment, referring to Fig. 8, the bucket 3 may be configured with a cylindrical curved protrusion 80 that surrounds the bucket body 4, and as yet another embodiment, referring to Fig. 9, the bucket 3 may be configured with an elliptical cylindrical curved protrusion 81 that surrounds the bucket body 4. [Explanation of symbols]

[0046] 1 Rubble stone injection device, 2 Rubble stone (crushed stone), 3 Bucket, 4 Bucket body, 5L, 5R Curved convex portion, 6 Dispersion injection means, 52U Upper dispersion shaft, 52D Lower dispersion shaft, 80 Curved convex portion, 81 Curved convex portion

Claims

1. A riprap dumping device for dumping riprap onto the seabed, comprising: Equipped with a bucket that can hold a large amount of rubble, The bucket is a rubble dumping device characterized in that it has a curved convex portion on its outer periphery that is curved so as to protrude outward when viewed in a plane.

2. The rubble dumping device according to claim 1, characterized in that a pair of the curved convex portions are arranged opposite each other.

3. 3. The rubble dumping device according to claim 1 or 2, wherein the outer surface of the curved convex portion is formed into a circular arc surface or an elliptical arc surface.

4. The rubble dumping device according to claim 1, characterized in that the curved convex portion is configured in a cylindrical or elliptical cylindrical shape so as to surround the bucket.

5. The bucket is provided with a dispersing means provided at a lower portion thereof for dispersing rubble to be thrown onto the seabed, The dispersion input means includes a plurality of dispersion shafts arranged at intervals along the horizontal direction and arranged at intervals along the vertical direction in a plurality of stages, The rubble dumping device according to claim 1, characterized in that each of the vertically adjacent dispersion shafts is arranged so as not to overlap in a plan view.

6. The rubble dumping device according to claim 5, characterized in that the dispersion shaft is formed in an inverted V shape when viewed from the front.

Images