JPH01247608A - Wave controlling structural body - Google Patents

Abstract

PURPOSE:To reduce the weight of a structural body and reduce the installation cost by opening a number of through holes on the bottom surface of the structural body and allowing said through holes to communicate to the space inside or outside the structural body. CONSTITUTION:A structure body 10 having a wave control wall 12 in semicircular form on a bottom plate 11 is installed on a thrown stone mound 14 built on the sea bottom 13, and a space 15 having a semicircular section is formed inside. A number of through holes 16, 16,... which lead to the inside space 15 are penetration-opened on the bottom plate 11 of the structural body 10. A pumping-up pressure due to the upward water pressure which acts onto the bottom surface, accompanied with the advance of waves, is dispersed and absorbed into the opened ports of the through holes 16 and reduced. Therefore, the weight for resisting the pumping-up pressure can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a wave control structure used as a breakwater or offshore breakwater.

(Prior Art) Conventionally, structures such as concrete caissons have often been used as breakwaters and offshore breakwaters. These structures are simply rectangular, trapezoidal for the purpose of reducing wave force, circular or other curved surfaces, and even retarding structures that allow waves to pass through or consume energy through disturbance. Many types of devices have been proposed, including those with internal spaces such as sections.

These 'PR structures are installed directly on rubble mounds on the ocean floor or on the ocean floor, and most of them are affected by the horizontal sliding force and vertical uplift by waves due to their own gravity or the gravity of sand, stones, etc. packed inside. I try to counter pressure.

(Problem U to be Solved by the Invention) Generally, a horizontal sliding force and a vertical lifting force act on a wave control structure installed on the seabed due to the progress of waves. On the other hand, with the conventional wave control structures described above, the horizontal force received from waves is reduced by devising the shape of the upper part, but the force acting on the bottom plate of the structure is Since the uplift force is not reduced, the larger the area of the bottom slab, the greater the weight must be increased in order to prevent slipping and overturning due to wave force.This results in larger structures and higher construction costs. There was also the problem that the construction period would be longer.

In view of these conventional problems, the present invention reduces the uplift force exerted on the structure by waves, thereby providing an economical wave control structure that does not require increased weight even when the bottom area is large. This is the purpose.

<Means for Solving the Problems> The present invention is characterized by solving the above-mentioned conventional problems and achieving the intended purpose. A plurality of through holes are opened in the bottom surface of the structure body that receives the water, and the through holes are connected to the '! f4 There is a wave control tank in the body that communicates with the space inside or outside the body.

(Function) This wave control structure not only reduces the uplift force acting on the bottom surface of the structure body by dispersing and absorbing the water pressure on the bottom surface through the opening of the through hole as the waves advance. The water pressure that enters through the opening of the hole acts downward on the top surface of the bottom plate, resisting the uplift force that pushes up the structure.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, and this wave control tank body has a horizontal body body 10 having a wave control wall 12 in a semicircular arc shape on a bottom plate 11, and a rubble mound 1 constructed on the seabed 13.
4, and a space 15 with a semicircular cross section is formed inside. When a wave advances from the front side of the structure main body 10, a force in the direction of the wave movement acting on the outer surface of the cylindrical wave control wall 12 acts toward the center of the cylinder. is pressed against the bottom side, so the structure is able to resist wave force even though the entire structure is lightweight.

The bottom plate 11 of the structure main body 10 has a large number of through holes 16, 16, . It can be made lighter and has an economical structure.

Next, an experimental example will be described in which it was confirmed that the uplift force acting on the bottom plate was reduced by providing a through hole in the bottom plate using a model similar to the structure of the embodiment shown in FIG. 1.

Figure 2 shows the bottom plate under the conditions of the experimental water depth (h) 35 cm at the embankment installation position, the radius of the semicircular part of the embankment body 25 CI+, the height of the upright part of the embankment body 5 am, the mound 410 openings, and the mound covering thickness 10.7 cm. These are the experimental results when the aperture ratio (εb) was changed to 0%, 5%, 10%, and 20% and an irregular wave with a plate wave period (T) of 2°6 seconds was applied. The horizontal axis is The relationship between wave height and uplift force is shown by taking the wave height (H) of the passing wave at the location where the structure is installed, and taking the uplift force (Pu) at the front heel of the dam body corresponding to the wave height on the vertical axis. be. In addition, when it has an opening (ε
The uplift force of b>0) is the value obtained by subtracting the downward force acting on the top surface of the bottom plate. The plotted data is the average wave height, plate wave height, and 1/10 for three different wave groups in the wave train.
Average wave pressure, 1/3 maximum wave pressure, 1/10 ML large wave pressure, and maximum wave pressure were used for the maximum wave height and maximum wave height.

From this figure, it can be seen that by providing an opening in the bottom plate, it is possible to reduce the uplift force to about 0 to 20% of that in the case where there is no opening.

3 and 4 show the results of a sliding experiment when the experimental water depth (h) was 30 cm and the other structural conditions were the same as in FIG. 2. The experiment used irregular waves with a plate wave period (T) of 2.6 seconds, and waves with five levels of plate wave height were applied to each of three different wave groups in the wave train, and the amount of movement of the levee body was measured. . In addition, the weight of the embankment body jt (W> is 401qr, 45
The horizontal axis of the diagram with three types of 0 kg and 50 kg is the highest wave height (H) passing the embankment body position, and the vertical axis is the cumulative sliding amount (S) when approximately 250 waves are applied. FIG. 3 shows the case where the bottom plate has no holes, and FIG. 4 shows the case where the bottom plate has an aperture ratio of 20%.

These figures show that when there are holes in the bottom slab, the wave height at which the embankment begins to slide increases, and the amount of sliding is also smaller than when there are no holes.

This is due to the effect of reducing uplift pressure, which means that the force that lifts the embankment body is reduced, making it difficult for the embankment body to move.

By providing the opening in the bottom plate in this manner, the uplift force is reduced, making it possible to significantly improve the stability of the embankment body.

(Effects of the Invention) As described above, the wave control tank body of the present invention has a plurality of through holes opened in the bottom surface of the horizontal support body, and the through holes communicate with the space inside or outside the structure body. Therefore, the uplift force due to the upward water pressure that develops on the bottom surface due to the progression of waves is dispersed and absorbed by the opening of the through hole, and is reduced, and the downward water pressure that acts on the top surface of the bottom plate resists the uplift pressure, so the uplift force is reduced. As a result, the weight of the structure can be reduced, the manufacturing and installation costs of the structure can be reduced, and the construction period can be shortened.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view of one embodiment of the wave control structure of the present invention, and FIGS. 2 to 4 are graphs showing the results of experimental examples. 10... Structure body, 11... Bottom plate,
12... Wave control wall, 13... Seabed,
14...Rubble mound, 15...Space, 16...Through hole.

Claims (1)

[Claims] A wave control structure in which a plurality of through holes are opened in the bottom surface of a structure body that is installed with at least the bottom submerged and receives waves on the front side, and the through holes are communicated with the space inside or outside the structure body. body.