JPS6237167B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves planting a plurality of piles in rows and columns in the underwater ground, and scattering wave-absorbing materials such as stones between and around each pile and on the underwater ground. It relates to a wave-dissipating structure in which a superstructure is constructed on the upper end of the pile.

Conventionally, the above-mentioned randomly stacked wave-absorbing materials have only exerted a wave-absorbing effect, and have not substantially resisted the pull-out force of the piles.

The present invention aims to provide a wave-dissipating structure whose stability is dramatically improved by increasing the pull-out resistance of the pile by the weight of the randomly stacked wave-dissipating materials, thereby increasing the resistance moment against external forces. A pile with a rectangular plate protruding horizontally fixed at the required height was used so that the weight of the wave-dissipating material stacked above it acted on the rectangular plate located near the underwater ground surface. The gist of this is that

This will be explained in detail below using illustrated embodiments.

FIG. 1 shows a pile a made of H-shaped steel 1. However, this pile a may be a steel pipe pile. Then, in a place where the pile a will be located near the water bottom ground surface when the pile a is driven into the water bottom ground, a right triangular steel plate 2 is attached, with one end face of the right angle side pointing in the vertical axis direction of the H-shaped steel 1. A rectangular plate 2' made of steel plate is placed and fixed on this steel plate 2 orthogonally, that is, horizontally, and its end face is also fixed to the side surface of the H-shaped steel 1, , whereby a T-shaped protrusion b is formed to protrude outward.

The construction of the wave-dissipating structure of the present invention using the pile a having the above-mentioned configuration is carried out, for example, as follows.

First, conventionally known steel pipe piles are set as parent piles 3 and driven into the underwater ground in rows and columns with appropriate spacing, and appropriate spacing is made between the parent piles 3 and 3 of each row of offshore and land side rows. Then, drive one or more of the piles a until the T-shaped protrusion b (particularly the square plate 2') is located near the water bottom ground surface. When the width between the main piles 3 on the offshore side and the land side is too wide, one or several H-shaped steel piles 3' may be driven in between. Next, the heads of each of the piles 3, 3' and a are connected by several horizontal beams 4 or diagonal members 5 or the like.
Next, from the top of the enclosure, wave-dissipating materials 6 such as stones or concrete blocks of a size that will not escape from the gaps between the piles are piled up as filling materials, and the wave-dissipating and root protection work is carried out. Large wave-dissipating materials 9 and 10 are piled up randomly, and the T-shaped protrusion b is buried in these randomly piled wave-dissipating materials, and then upper cast-in-place concrete 8 is placed at the head of each pile, It and the horizontal beam 4 etc. are integrally and firmly connected.

In addition, since this alone will not reduce the amount of waves and drifting sand passing through, an impermeable wall 7 may be installed along the pile 3' in order to block them, but in this case, after installing the impermeable wall, A wave-dissipating material 6 as a filling material is introduced and filled from the top of the rectangular cylindrical enclosure.

In the above embodiment, since the pile a is not a parent pile, the attachment position of the T-shaped protrusion b can be determined in accordance with the degree of penetration of the parent pile 3.
That is, since the pile a is driven as an intermediate pile after the main pile 3 is driven to a predetermined position and depth, the depth at which the pile a can be driven can be easily determined. Further, since the pile a may have a slightly shallower penetration depth than the parent pile 3, the T-shaped protrusion b can be easily aligned near the water bottom ground surface. Even in the unlikely event that the T-shaped protrusion b of the pile a is above the water bottom ground level due to an obstruction, the T-shaped protrusion b of the pile a should be placed in the T-shaped It is possible to ride and lock onto the protrusion b.

The wave-dissipating structure constructed as described above is constructed by connecting the heads of each pile with multiple horizontal beams, diagonals, etc.
Since it is fixed integrally with concrete, etc., when the wave-dissipating materials 6, 9, and 10 act on the intermediate pile (a) and a pull-out resistance force is generated, it is applied to the entire wave-dissipating structure through the pile head. As a result, a strong pull-out resistance force is imparted to the structure as a whole.

In addition, if the wave-dissipating material such as stones or concrete blocks filled as filling material is too large and there is a risk that it will not act as a uniform load on the T-shaped protrusion b of the pile a, the area around the upper part of the T-shaped protrusion b Wave-absorbing materials of appropriate sizes are selected and piled up randomly to achieve a uniform load, and then normal wave-absorbing materials are filled inside the enclosure.

In conventional wave-dissipating structures with pile structures, when an external force such as waves is applied, a tensile force (pulling force) is applied to the pile on the side where the external force is applied, and a compressive force is applied to the pile on the opposite side. In this case, the force of the pile that resists the tensile force is only a part of the weight of the cast-in-place concrete at the top (self-weight of the structure) and the pull-out resistance of the pile itself, and the wave-absorbing material stacked loosely is The frictional resistance generated between the piles only contributed to the pull-out resistance of the pile. Since this pulling resistance force is generally small, when the external force becomes large, even if the pile on the compression side has sufficient supporting force, the pile on the side on which the external force acts will rise. Therefore, when a periodic external force such as a wave acts on the pile, the pile repeatedly floats up and down, and each time the pile rises, earth and sand enters beneath it, causing the pile to return to its original position. This will cause the pile to gradually rise.
This creates a very large moment and deformation at the pile head, which eventually causes the structure to fail.

However, in the wave-dissipating structure of the above embodiment, T
It has a T-shaped protrusion b, and the wave-dissipating materials 6, 9, and 10, which have conventionally been piled up as filling materials, wave-dissipating materials, and foundation reinforcement works, have a small contribution to the pulling force. These loads are applied to pile a in order to lock it to pile b, and that force acts on the entire structure at the same time as part of the weight of the upper cast-in-place concrete 8 and the pull-out resistance of the pile in the ground, and the resistance moment This resulted in a rapid increase in structural stability, resulting in a significant increase in structural stability.

Note that the location where the pile a is used is not limited to the above embodiments, and if the direction in which external forces such as waves act is constant, the pile a may be used only on the side where the external force acts, and It is used not only as an intermediate pile but also as a parent pile, and a conventionally known ordinary pile may be used on the opposite side.

Now, in the above case where external wave force acts from a certain direction, comparing the resistance moments of the wave-dissipating structure of the present invention using the pile a and the conventional wave-dissipating structure not using the pile a, the following is obtained. This is true (the pull-out resistance of the pile itself is extremely small, so ignore it).

That is, in the conventional structure shown schematically in Figure 4, the external force is P, the structure's own weight (subtracting the buoyant force) is W ₁ , and the arm of the moment of resistance is l.
Then, the moment of resistance of the structure is W ₁ ×l, and the relationship W ₁ l>ph...(1) holds, and the stability of the structure is maintained.

On the other hand, in the structure of the present invention shown in a simplified form in FIG. 5, the external force is P, the structure's own weight (subtracting the buoyant force) is W ₂ , the arm of the moment of resistance is l, and the T-shaped protrusion b If the weight of the wave-dissipating material above it (subtracting the buoyant force) acting on it is W ₃ , the moment of resistance of the structure is W ₂ ×l + W ₃ ×2l, and W ₂ l + 2W ₃ l＞ph ……( 2) is a condition for the stability of the structure.

2W ₃ l, which is not in equation (1), is added to equation (2), and the dead weight of the randomly stacked wave-dissipating material (those above the T-shaped protrusion b), which previously only played the role of wave-dissipating, is A is held down, the resistance to pulling out is increased, and naturally a large resistance moment is obtained. In other words, when an external force tries to pull out the pile, the randomly stacked wave-absorbing material above the T-shaped protrusion b acts effectively as passive earth pressure.

As is clear from the above description, according to the wave-dissipating structure of the present invention, among the plurality of piles installed in rows and columns in the underwater bed ground, at least the piles to which external force acts have a rectangular plate near the underwater bed ground. The rectangular plate is fixed protruding horizontally, and the weight of the wave-absorbing material stacked above it acts on this square plate, increasing the pull-out resistance of the pile, thereby increasing the resistance moment against external forces and stabilizing it. You can dramatically improve your sexuality.

[Brief explanation of the drawing]

The drawings are for explaining the embodiment of the present invention, and Fig. 1 is a perspective view of a pile, Fig. 2 is a cross-sectional view of a wave-dissipating structure, Fig. 3 is a plan view of the same, and Fig. 4 is a conventional one. FIG. 5 is a simplified explanatory diagram of the wave-dissipating structure of the present invention. 6, 9, 10... Randomly piled wave-dissipating material, a... Pile,
2'...Square plate.

Claims (1)

[Claims] 1 In a wave-dissipating structure in which wave-dissipating materials such as stones are piled up randomly between and around multiple piles planted in rows and columns in the underwater bed ground, and a superstructure is constructed on the top of the piles. , a wave-dissipating structure characterized in that a rectangular plate fixed horizontally protruding near the underwater ground surface of at least one of the plurality of piles to which an external force acts is buried in the lamination of the randomly stacked wave-dissipating material. .