JPH0375684B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to rivers, harbors, etc., where the earth and sand at the bottom of underwater structures are washed away by water currents and waves, causing the structures to sink or tilt. This invention relates to a device for preventing

Prior art As a scour prevention device for such underwater structures,
Conventionally, a heavy object is attached to the edge of a protrusion that protrudes from the structure of a flexible sheet body that is laid and fixed at the bottom of an underwater structure, and the heavy object is scoured and buried in earth and sand. A structure is known in which the scouring of earth and sand at the bottom of a structure is prevented by
-35990.

In other words, the former of the above-mentioned publication discloses a structure in which a cylinder is attached to the back side of the free edge of the seat body, leaving gaps here and there, and the cylinder is filled with heavy objects such as crushed stone, concrete, iron material, etc. Such a sheet body is laid on the bottom of the water with the cylindrical body filled with the heavy object facing downward. This cylindrical body moves up and down with the seat body due to the water current or waves, and due to this floating movement and the scouring of the lower surface of the tip of the seat body caused by the water flow, the seat body moves with the cylindrical body filled with heavy objects at the tip. It is curved downward and buried in the soil at the bottom of the water, and once buried to a certain extent, it becomes stable and no further scouring or burying will occur.

Furthermore, in the latter part of the above-mentioned publication, a flexible sheet body is laid at the bottom of the structure, and a heavy object is attached to the free edge of the swingable protrusion of the seat body that protrudes from the structure. In this example, the protruding part and the heavy object are fixed by being buried in the earth and sand by the rocking of the protruding part caused by water currents and waves.

Problems to be Solved by the Invention However, in such conventional scour prevention devices, heavy objects are disposed intermittently with gaps remaining in the width direction of the sheet main body, so that the weight of the scour end portion of the sheet is The progress of scouring is different between the lower part of the object and the lower part of the part where there is no heavy object, so the sheet body is not buried uniformly, causing local distortion, and the load is concentrated in this part, or There was a problem in that the water stream passed through areas where heavy objects were not present and washed deeper into the seat body than necessary.

Means and Effects for Solving the Problems Therefore, the present invention improves the conventional scour prevention device as described above so that the entire sheet is buried evenly and effortlessly. Therefore, in the present invention, a sheet laid on the bottom of an underwater structure is extended from the structure, and a free end is provided on the upper surface of the sheet at a distance from the free end edge toward the structure. A continuous and substantially parallel heavy object is placed on the edge, and the heavy object is intermittently connected to the sheet.

According to the present invention, since the heavy object is continuous over substantially the entire width of the sheet, and the edge of the sheet extends further outward from the heavy object,
Due to the movement of the edge due to water current or waves,
The area under the heavy object is reliably and evenly washed over the entire width of the sheet, and the sheet is free from local deformation and
It is buried uniformly in the bottom of the water without distortion, and no concentrated load is applied to the connection between the heavy object and the seat.

Embodiment The present invention will be described below with reference to an illustrated embodiment. In Figure 1, 1 is an underwater structure such as a caisson, which is installed on the water bottom to form a seawall, embankment, etc. in rivers and ports.
A sheet 3, which is part of the scouring prevention device according to the present invention, is laid between the water bottom 2 and the water bottom 2. The sheet 3 is a flexible sheet made of synthetic resin, rubber, or the like, and has an extension 4 extending from the structure 1 along the water bottom 2. There is an H near the tip of the extension part 4.
A heavy object 5 made of shaped steel or the like is placed, and the extending portion 4 has an end edge 6 that projects further outward from the heavy object 5 and terminates in a free edge 7.

As shown in FIG. 4, the sheet 3 is formed by connecting a large number of sheet pieces 8 laterally along the structure 1, and the sheet pieces 8 are connected to each other by connectors 9. ing. For example, each sheet piece 8 has a width B of about 6 m, a length L of about 15 m, a thickness of about 5 mm, and has sufficient flexibility.

Near the free end edge 7 of each sheet piece 8, the heavy objects 5 are placed at a distance from the free end edge 7 toward the structure 1, and approximately in one row on the free end edge 7. An edge portion 6 is formed on the outer side of the heavy object 5. The heavy object 5 is made of H-shaped steel material as described above,
It extends over substantially the entire width of the sheet piece 8. The heavy object 5 is connected to the sheet piece 8 via connecting devices 10 intermittently along its longitudinal direction, that is, intermittently. The length l of the edge 6 from the heavy object 5 to the free edge 7 is
The length is such that it will not be turned inside the heavy object 5, that is, on the structure 1 side, by water currents and waves.

FIG. 5 shows the connection 10 between the heavy object 5 and the seat piece 8 in more detail. As shown in the figure, a hook 11 is fixed to the heavy object 5 by welding or the like, while a reinforcing sheet 12 is attached to the sheet piece 8, and an engagement hole is formed on this reinforcing sheet 12. A mounting piece 14 having 13 is fixed. A triangular ring 15 is locked in the engagement hole 13, and a shackle 16 is passed through the triangular ring 15 and the hook 11, so that the heavy object 5 is movably connected to the seat piece 8.

FIG. 6 shows details of the connector 9 for connecting adjacent sheet pieces 8, and each sheet piece 8 is provided with an attachment piece 1 similar to the attachment piece 14.
7 and 18 are fixed, a rope 19 is passed through one attachment piece 17, a triangular ring 20 is passed through the other attachment piece 18, and these ropes 19 and triangular ring 20 are connected by a ring piece 21. be.

Since this embodiment is configured as described above,
When the extension part 4 is laid along the water bottom 2 as shown in FIG. 1, the edge part 6 at the tip moves due to water flow or waves, and the edge part 6 and the heavy object 5 move as shown in FIG. The lower part of the area is scoured. In this case, since the heavy object 5 extends continuously over the entire width of the sheet 3, the above-mentioned washing is performed evenly in the width direction of the sheet 3,
Further, even if the end portion 6 is curled up, the heavy object 5 holds down the back thereof as a whole, so that the scouring action progresses reliably.

In this way, the sheet 3 is buried in the soil of the water bottom 2 together with the heavy object 5, and becomes stable in the state shown in FIG. 3, preventing the lower part of the structure 1 from being scoured. Since the lower part of the sheet 3 is evenly scoured, the entire sheet 3 is sunk and buried uniformly, and there is no risk of damage or breakage due to local excessive deformation. Further, there is no fear that a concentrated load will act on the connecting portion between the heavy object 5 and the seat 3.

Effects of the Invention As described above, in the present invention, a sheet laid on the bottom of an underwater structure is extended from the structure,
A heavy object is placed on the upper surface of this sheet, extending continuously from the free end edge of the sheet at a distance from the free end edge toward the structure side, and approximately parallel to the free end edge, and the heavy object is intermittently applied to the sheet. Because they are connected, the bottom of the water at the bottom of the sheet is evenly and reliably scoured in the width direction of the sheet, and the sheet as a whole sinks and buries into the soil at the bottom of the water evenly and effortlessly, and is not partially overburdened. There is no risk of severe deformation or damage due to excessive load, and scour of the lower part of the underwater structure can be reliably prevented.

In addition, since the edge of the sheet protrudes in front of the heavy object, the movement of the edge promotes scouring of the bottom of the water at the heavy object, and the heavy object quickly sinks and buries. Stable state is reached early.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIGS. 1 to 3 are longitudinal sectional views showing the state of the device installed on the bottom of the water at various stages, and FIG. 4 is a plan view of the device.
FIG. 5 is a perspective view showing the connecting portion between the heavy object and the sheet pieces, and FIG. 6 is a perspective view showing the connecting portion between the sheet pieces. DESCRIPTION OF SYMBOLS 1... Structure, 2... Water bottom, 3... Sheet, 4... Extension part, 5... Heavy object, 6... Edge part, 7... Free end edge, 8...
Sheet piece, 9... Connecting tool, 10... Connecting tool, 11...
Hook, 12... Reinforcement sheet, 13... Engagement hole, 14
... Mounting piece, 15... Triangular ring, 16... Shackle, 17, 18... Mounting piece, 19... Rope, 20
...Triangular ring, 20...ring piece.

Claims (1)

[Claims] 1. A sheet laid on the bottom of an underwater structure is extended from the structure, and on the top surface of this sheet, a sheet is placed continuously and approximately parallel to the free edge at a distance from the free edge toward the structure. A scour prevention device for an underwater structure, comprising placing an extending heavy object and intermittently connecting the heavy object to the sheet.