JP7333880B1 - Scouring prevention method for underwater structures - Google Patents

Abstract

An object of the present invention is to provide a method for preventing scour of an underwater structure by which bagging units can be spread safely, efficiently, and without any gaps. [Solution] A step of: a) locking a plurality of bagging units to a hanging device and lifting the hanging device with a lifting machine; and b) lowering the hanging device and installing the bagging units on the bottom surface of the water. c) removing the bagging unit from the hanging device, the bagging unit has a water droplet shape when viewed from the side in the suspended state in the step a, and is shaped like a water droplet on the bottom surface of the water in the step b. A method for preventing scour of an underwater structure, characterized in that when installed, the bagging units spread laterally and become flat, and in step a, the plurality of bagging units are arranged so as not to overlap each other in a plan view. . [Selection diagram] Figure 3

Description

TECHNICAL FIELD The present invention relates to a method for preventing scouring of underwater structures provided on the bottom of the water.

In the past, scouring prevention work for underwater structures such as offshore wind power generation facilities, caissons, bridge pier foundations, etc. has been carried out by lining up and spreading bagging units on the water bottom around underwater structures.
The bagging unit is a bag filled with a filling material, and when placed on the bottom of the water, the planar shape is almost circular. Sand is partially exposed, and it becomes impossible to fully demonstrate its role as a countermeasure against scouring.
For this reason, Patent Document 1 discloses a method in which bagging units that do not change in size when being lifted and installed are lifted so that they overlap in plan view and are laid on the bottom of the water so that the bagging units are meshed to eliminate the gap. Are listed.

Japanese Patent No. 7057847

When anti-scouring work is performed on the bottom of the sea, the working hours of underwater work by divers are restricted. In addition, there is a danger that divers may come into contact with structures on the bottom of the water or a bagging unit installed on the bottom of the water due to the effects of waves and currents.
In particular, the offshore wind power generation facilities that have been adopted in recent years are large, and it is necessary to lay scouring prevention works over a wide area. is an issue.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for preventing scouring of an underwater structure, which solves the above-described problems and allows bagging units to be safely and efficiently spread without gaps.

The present invention comprises the steps of: a) locking a plurality of bagging units to a hanging device and lifting the bagging unit with a lifting machine; and b) hanging the bagging unit to set the bagging unit on the bottom of the water and c) removing the bagging unit from the suspension device, wherein the bagging unit has a waterdrop shape in a side view when suspended in the step a, and is attached to the bottom surface of the water in the step b. When installed, it expands in the horizontal direction and becomes flat, and in the step a, the plurality of bagging units are arranged in two stages in the vertical direction with different lifting heights, and the bagging units are adjacent in plan view. provide a method for preventing scouring of an underwater structure, characterized by arranging them in different stages and having a space therebetween in a plan view .
The bagging unit may be engaged with the hanging device via a hook, and in step c, the hook may be opened by an operation from above water to remove the bagging unit from the hanging device.
In the step a, the plurality of bagging units, including those arranged in different stages, may be hung in a zigzag pattern when viewed from above .

The present invention can obtain at least one of the following effects by the means for solving the above problems.
(1) Since the bagging units are suspended so that their outer edges do not overlap, the waterdrop-shaped bagging units can freely spread outward when placed on the bottom surface of the water.
(2) By freely expanding outward, it is possible to exhibit the effect of filling the gaps between the bagging units.
(3) By changing the distance from the suspension device, the lifting height changes, and the arrangement order on the bottom of the water can be adjusted.
(4) Since the bagging unit can be removed from the ground, underwater work by a diver is unnecessary, and the bagging unit can be installed safely and efficiently.

Explanatory drawing of an anti-scouring structure constructed by the anti-scouring method for underwater structures according to the present invention. Explanatory drawing of bagging unit Explanatory drawing of a state in which the bagging unit locked to the hanging device is lifted. A plan view of a state in which multiple bagging units are hung Explanatory drawing of a state in which multiple bagging units are hung Explanatory diagram (1) of the state in which the bagging unit is suspended Explanatory diagram (2) of the state in which the bagging unit is suspended

Hereinafter, the method for preventing scouring of underwater structures according to the present invention will be described in detail with reference to the drawings.

<1> Anti-scouring structure The anti-scouring structure constructed by the anti-scouring method of the present invention has a bagging unit 1 installed on the bottom surface 2 of the water around the underwater structure, and the bagging unit 1 suppresses the bottom surface 2 of the water. This prevents the earth and sand on the bottom surface 2 of the water from being washed away by waves and water currents (Fig. 1).

<2> Bagging Unit The bagging unit 1 is a bag body 11 for civil engineering work filled with a filling material 12 (FIG. 2).

<2.1> Bag body The bag body 11 is made of a Raschel net fabric in which a synthetic fiber thread such as polyester is knitted in a single layer or a double layer.
The mesh of the bag body 11 is set to a dimension that prevents the filling material 12 from slipping out.

<2.2> Inner Filling Material The inner filling material 12 is a material with which the inside of the bag body 11 is filled.
For the filling material 12, for example, natural aggregates such as cobblestone, crushed stone, and crushed stone, concrete debris, and the like are used.

<2.3> Hoisting of bagging unit The bagging unit 1 has a hanging rope 13 for lifting.
By lifting the suspension rope 13 upward, the suspension rope 13 is pulled, the upper part of the bag body 11 is lifted, and the filling material 12 above the inside of the bag body 11 is drawn toward the center of the bagging unit 1. As a result, the bag body 11 is drawn inward. On the other hand, since the weight from above acts on the filling material 12 below the inside of the bag body 11, the amount of the stuffing material 12 that is drawn toward the center is reduced, and the bottom bulges downward in a hemispherical shape. Therefore, when the bagging unit 1 is lifted, it becomes a waterdrop shape (Fig. 2(a)).

<2.4> Arrangement of the bagging unit on the bottom of the water When the bagging unit 1 is suspended on the bottom of the water 2, the weight of the filling material 12 spreads the bag body 11 outward and deforms it into a flat shape, resulting in a bun shape. (Fig. 2(b)).

<3> Suspension Device The scouring prevention method of the present invention is performed by suspending the bagging unit 1 using the suspension device 3 (Fig. 3).
The suspension device 3 includes a main body 31 made of a steel frame and a hook 32 suspended from the main body 31. - 特許庁The hanging rope 13 of the bagging unit 1 is hooked to the hook 32 to lift it, but the hook 32 is not limited to the hook 32 as long as the bagging unit 1 can be lifted by pulling up the hanging rope 13 .
Further, the hook 32 of this embodiment has a hook opening rope 33, and by pulling up the hook opening rope 33, the hanging rope 13 of the bagging unit 1 can be removed from the hook 32. This configuration has been used conventionally, and can be appropriately used not only for the hook release rope 33, but also for any form in which the hanging rope 13 of the bagging unit 1 can be removed from the hook 32 from a remote location.
The lifting device 3 is lifted by a lifting machine (not shown).

<4> Scouring prevention method <4.1> Lifting of the bagging unit 1 The hanging rope 13 of the bagging unit 1 is engaged with the hook 32 of the lifting device 3, and the bag is lifted by lifting the lifting device 3 with a lifting machine. Lift the stuffing unit 1.
A plurality of bagging units 1a and 1b are lifted from the hanging device 3. In this embodiment, the bagging units 1a and 1b are staggered when viewed from above and the maximum diameter of the waterdrop-shaped bagging unit 1 is increased when viewed from above. (Fig. 4). In addition, it can also be hung so as to form a lattice when viewed from above.
When hanging in a zigzag pattern, the bagging unit 1a arranged in a polygonal shape such as a square or hexagonal shape in plan view and the bagging unit 1b arranged in the center have a lifting height (distance from the hanging device 3). is changed so that the bagging unit 1b in the center is high (the distance from the hanging device 3 is short) (Fig. 5).

<4.2> Suspension When the suspension device 3 is suspended by a lifting machine, the lower bagging unit 1a is first suspended on the water bottom surface 2, and the weight of the filling material 12 pushes the bag body 11 outward. It spreads to a flat shape and becomes a bun shape (Fig. 6), but a gap is formed under the bagging unit 1b, which is the center of the polygonal shape in plan view.
When the hanging device 3 is further lowered, the bagging unit 1b fits in the gap and the bag body 11 expands outward and deforms (FIG. 7). In order to fill the gaps between the bagging units 1a with the bags 11, it is preferable to use the bagging units 1b that are waterdrop-shaped when lifted and expand outward and deform into a flat shape when hung.
If the outer edges of the bagging units are overlapped when lifted, the bagging units 1a and 1b of the present embodiment overlap each other without being spread out by coming into contact with the adjacent bagging units when installed. Since the bagging units 1a and 1b are suspended so as not to be separated from each other, the water drop type bagging unit 1b can freely spread outward by providing a space between the adjacent bagging units 1a and 1b, and can exhibit the effect of filling the gap.

<4.3> Removal of bagging unit After the bagging unit 1b is arranged in the gap, the hanging rope 13 of the bagging unit 1 is removed from the hanging device 3 . In this embodiment, the hanging rope 13 of the bagging unit 1 can be removed from the hook 32 by pulling up the hook release rope 33 of the hook 32 from the ground.

1 bagging unit 11 bag body 12 filling material 13 suspension rope 2 water bottom surface 3 suspension device 31 main body 32 hook 33 hook opening rope

Claims (3)

a) locking a plurality of bagging units to a hoisting device and hoisting the hoisting device with a lifting machine;
b) suspending the suspension device to install the bagging unit on the bottom of the water;
c) removing the bagging unit from the suspension device;
The bagging unit has a waterdrop shape in a side view when suspended in the step a, and expands in the lateral direction to become flat when installed on the bottom surface of the water in the step b,
In the step a, the plurality of bagging units are arranged vertically in two stages with different lifting heights, and the bagging units adjacent to each other in plan view are arranged in different stages and are spaced apart in plan view. characterized by having a space in
A method for preventing scouring of underwater structures. The bagging unit is locked to the hanging device via a hook, and in the step c, the hook is opened by an operation from the water to remove the bagging unit from the hanging device.
The method for preventing scouring of an underwater structure according to claim 1. In the step a, the plurality of bagging units, including those arranged in different stages, are hung in a zigzag shape when viewed from above,
The method for preventing scouring of underwater structures according to claim 1 or 2.

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