JPH06975B2 - Construction method of steel plate cell breakwater - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of constructing a steel plate cell breakwater, and in particular to a method of constructing each cylindrical steel plate cell structure constituting it.

(Prior Art) In Japan, the development and utilization of the coastal area facing the inner bay has been conventionally promoted, but in recent years, the development of the coastal area facing the open ocean where the sea condition is severe has been promoted. In particular, it has become necessary to secure domestic fishery resources due to the depletion of overseas fishery resources, and to secure appropriate marine leisure areas as an extension of living.

However, even in Japan, which is surrounded by the sea on all four laps, there are few sea areas that are already easy to develop, and there is a demand for the development of sea areas that have never been considered.

(Problems to be solved by the invention) In developing these open ocean coastal areas, while conserving the coast,
A new type of wave-dissipating structure is required to create fisheries resources or create oceanic recreation areas. That is, the following conditions must be satisfied at the same time in order to achieve such an objective.

To maintain water quality, be transparent for coastal conservation, be installed in deep water (10 to 30 m), be able to withstand large waves (wave height 5 to 15 m), be easy to construct, economical To be.

One of the applicants of the present invention as a breakwater satisfying such a condition is to arrange one or more rows of steel cell structures in accordance with Japanese Patent Application No. 61-209136 (Japanese Patent Laid-Open No. 63-63807). We proposed a transmission type breakwater that promotes energy loss of waves by providing a slit part on the upper part of the outside of the dam and a water retaining chamber behind it. The wave canceling mechanism of the water retaining chamber having such a slit portion utilizes the wave loss due to the energy loss when the water particles pass through the slit portion and the phase difference between the reflected waves. By combining such a wave-breaking mechanism and a steel cell structure such as a steel plate cell having a rooting that has already been put into practical use, a breakwater that satisfies the above conditions and has a high wave-breaking effect is realized. .

However, in Japanese Patent Application No. 61-209136 (Japanese Patent Laid-Open No. 63-63807), the structure of the slit portion and the outer wall of the water retaining chamber is made of cast-in-place reinforced concrete, or the slit portion is formed by cutting the cell steel plate. I am trying. Of these, if the slit portion is configured only by cutting the cell steel plate into a slit shape, the rigidity of the slit portion is obviously insufficient, and it is considered that the structure cannot withstand the acting wave force. Reinforcement with cast-in-place concrete is inevitable. Therefore, it is considered that the concrete construction procedure is as follows.

Placing or installing steel plate cells Filling the filling material to the lower level of the bottom plate of the water chamber Inserting the slit and the outer wall of the water chamber Reinforced concrete Placing the filling material behind the water chamber Cutting the slit steel plate of the cell lid Concrete, anti-corrosion concrete, top concrete construction However, in this case, the following problems are observed.

On-site construction of the slit part and the outer wall of the water retention chamber is
It takes a long time to assemble the formwork, place and cure concrete, and remove the formwork.Because of this, the inner part of the back of the water retention chamber is the last work, so the rigidity of the upper part of the cell is insufficient, and due to external forces such as waves. , The cell steel plate is easily deformed during construction.

According to the experiment conducted by the applicant, it is clear that the depth of the water retaining chamber is suitable to be 1/2 to 1/4 of the addition of water. To make it below the water level, it is difficult to construct it because it is necessary to assemble the rebar and formwork underwater.

The reliability of concrete is lacking because it requires offshore work.

Therefore, in view of such drawbacks, the present inventors installed a slit precast concrete box in a steel plate cell filled up to the lower part, and invented a structure in which it is integrated with a steel plate cell by a filling material such as concrete, I applied for a separate patent.
After that, when we continued to study, according to the method using the above-mentioned precast concrete box, it was possible to fill the inside of the water tank immediately after the precast concrete box was installed, and the period during which the cell steel plate was easily deformed until the filling was completed. It can be greatly shortened.

The effect of deepening the water depth of the water retention chamber can be expected by eliminating the rebar / formwork assembly in the water, but it is necessary to even out the filling surface before installing the precast concrete box. Since it has to be done manually, it takes about 1 to 2 days, during which the upper part of the cell steel plate is easily deformed.

When the filling material sinks, the weight of the precast concrete box is directly added to the steel plate cell, and the cell steel plate may buckle locally.

It turned out that there are problems such as.

Therefore, an object of the present invention is to provide a practical construction method of a steel plate cell breakwater having a slit portion and a water storage chamber and having excellent wave-dissipating properties, in order to solve the above problems.

(Means for Solving the Problems) Here, the gist of the present invention is to provide a transmission type steel plate cell breakwater in which columnar steel plate cell structures are arranged in a single row or a plurality of rows at a required interval. In the construction method, a slit portion is provided in advance on at least a part of the outer upper side, and a steel partition wall portion is provided behind it in the breakwater extension direction,
Cylindrical steel plate cell provided with a water retarding chamber connected to the slit portion is placed or installed on the sea bottom facing the slit portion to the offshore side, and after filling the filling material to the bottom plate bottom level of the water retaining chamber, Steel plate cell wave-dissipating feature characterized in that each of the columnar steel plate cell structures is constructed by continuing to put a filling material in the portion behind the water storage chamber and constructing a bottom slab concrete for the water storage chamber in water. It is the construction method of the bank.

Even in the present invention, after the filling of the filling material is completed, as in the conventional example, the construction of the lid concrete at the top of the steel plate cell, the construction of the upper concrete, and the construction of the anticorrosion concrete are performed to form a cylindrical steel sheet. The construction of the cell structure is completed.

(Operation) As described above, according to the present invention, a cylindrical steel plate cell having a slit portion made of steel and an interval of the water chamber is manufactured in advance, and after being placed or installed on the sea bottom, the inner filling and the bottom plate of the water chamber are formed. Since concrete, lid / top and anticorrosive concrete are respectively constructed, the construction method will be sequentially described below with reference to the accompanying drawings.

FIG. 1 is a bird's-eye view of a steel plate cell breakwater constructed by the method of the present invention. In the illustrated example, cylindrical steel plate cell structures (also simply referred to as “steel plate cells”) 10 are arranged in a row at regular intervals. Each steel plate cell 10 is provided with a slit portion 12 on the upper side facing the open sea, and a water retaining chamber 14 is formed behind it. When a wave hits this slit portion 12 facing the direction of the wave, part of it returns as a reflected wave, but the rest passes through the slit portion 12 and loses the energy of the wave and enters the loss of water 14, then the partition wall portion 16 It becomes a reflected wave at the slit part 12
It is canceled by the phase difference with the reflected wave generated in.

The size and arrangement of each steel plate cell may be appropriately set according to the situation of the construction sea area.

Figures 2 (a) and (b) show the steel plate cells 10 that have been completed.
FIG. 3 is a schematic vertical sectional view and a plan view of FIG. B in Figure 2 (b)
As can be seen from FIG. 2A which is a cross-sectional view of -B,
The front half of the steel plate cell 10 is occupied by a water retaining chamber 14, and a slit portion 12 composed of a slit member 17 having a steel box-shaped cross section and a vertical slit 13 is provided on the front surface. To prevent local deformation of the slit member 17,
It is preferably filled with concrete. A bottom slab concrete 15 is provided on the bottom surface of the water retaining chamber 14. on the other hand,
The back surface side of the water retaining chamber is separated by a partition wall portion 16, the back side of which is filled with a filling material, and the upper part of the filling material is covered with stones 19 and a cover concrete 20. The upper concrete 21 is placed on the lid concrete 20, and the top surface is
Make up eighteen. Reinforced concrete beams 22 may be provided on the tops of the slit portion 12 and the partition wall portion 16 for reinforcement.

The anticorrosion concrete 23 may be provided if necessary.

FIGS. 3A and 3B show an example of the steel plate cell 11 according to the present invention which is manufactured in advance in a factory or the like. A vertical slit 13 is provided on the upper part of the side facing the outside of the bank, and the slit member 17 that constitutes the slit portion 12 together with the vertical slit 13 is made of a steel plate so as to withstand the acting wave force. It has a box-shaped cross section. Further, in the vicinity of the center of the cell diameter behind the slit portion 12, there is provided a steel partition wall 16 in the extending direction of the breakwater. The position of the partition wall portion 16 is determined depending on the condition of the working wave.

In FIG. 3, the steel partition wall 30 forming the partition wall portion 16 is shown.
Is a steel plate welded with vertical and horizontal stiffeners 32 and upper and lower transverse girders.
Although the structure is based on 41, as shown in Fig. 4, steel sheet pile
You may use the partition 34 which consists of 43 and the cross beam 41. The planes AA and BB in FIG. 4 are those in FIG. 3A.

In these illustrated structural examples, the connecting beam 36 is provided in the central portion of the transverse girder below the partition wall, but a connecting beam 38 is provided to the transverse girder upper transverse girder depending on the external force applied, or the upper and lower joint beams are omitted. You may The upper and lower ends of the slit member 17 are fixed to the reinforcing girder 40 in the circumferential direction. A steel panel 42 for a scrap frame is attached to the side surface of the water retaining chamber. The bottom of the water retaining chamber is a through-hole, and the fixed plate is cast concrete in-situ.
Although not shown in the figure, vertical and horizontal stiffening materials may be welded to the inside of the cell steel plate, if necessary.

The concrete construction procedure in the present invention is as follows.

Steel slits, production of steel plate cells with bulkheads Steel plate cell placement or equipment Filling of filling material Filling chamber bottom concrete / slit Filling concrete / filling chamber side wall concrete lid concrete, top concrete casting, anticorrosion concrete Steel slits Manufacture of steel plate cell with partition wall: The body of the steel plate cell used in the present invention is manufactured in advance in a yard or factory on land by, for example, a welding assembly method. Reinforcement materials such as beams and girders will be provided as necessary so that the structure will withstand the conditions of the planned sea area. Since the production of the steel plate cell itself is already apparent to those skilled in the art from the above description, further description will be omitted.

Placing or equipment of steel plate cells: Steel plate cells with slits and bulkheads manufactured for land yards, etc.
No. 11 is properly transported to the construction area and placed or installed on the sea floor. As a driving method, a method of interlocking several large vibro hammers has already been put into practical use. It may be a so-called stationary cell structure, which is installed on the sea floor when the seabed ground conditions are appropriate.

Filling the filling material: After the casting, the filling material is promptly put in the steel plate cell 11. The filling material is poured into the entire section of the steel plate cell at the partition bottom end level, that is, at a level deeper than the bottom surface of the water retention chamber bottom plate, and at the shallower level, only at the partition wall rear surface side. As the filling material, suitable materials such as gravel, sand, and debris are used.

That is, in the present invention, after filling the steel plate cells, the filling material can be charged all at once to a required level near the top end, whereby the filling non-construction period in which the cell steel sheet is easily deformed can be about several hours. it can.

Retaining chamber bottom plate concrete, slit filling concrete,
Placement of concrete in the side wall of the water retaining chamber: After the filling material is added, the bottom slab concrete 15 for the water retaining chamber is constructed in water. The bottom slab concrete 15 may be unreinforced concrete, and for example, by using special concrete having high viscosity and little material separation, highly reliable concrete construction is possible even in water.

Concrete is filled in the voids 44 of the water retaining chamber side method. A mold for this purpose is attached as a scrap frame 42 made of steel at the time of manufacturing the cell.

Further, the inside of the slit member 17 is filled with concrete as necessary in order to prevent local deformation of the steel sheet due to wave force.

Cover concrete, anti-corrosion concrete, top concrete pouring: After the slit 12 and the water storage chamber 14 are configured as described above, or inside the steel plate cell behind the lid water storage chamber 14, the filling material up to near the top end. After charging, a lid concrete 20, an upper concrete 21 and, if necessary, an anticorrosion concrete 23 are applied to the upper portion of the steel plate cell for finishing. At this time, the strength of the upper beam of the swimming room is a steel reinforcement girder,
If the beams, 38, 40 and 41 alone are insufficient, they can be reinforced by placing reinforced concrete beams 22.

It should be noted that securing the rigidity of the steel plate cell can be easily dealt with by appropriately reinforcing the steel plate cell, as will be apparent to those skilled in the art from the above description.

(Effects of the Invention) As described above in detail, the following effects can be expected by the present invention.

Immediately after placing the steel plate cells, the filling material can be added to the vicinity of the cell top, and the period during which the cell shell is easily deformed from the placing of the steel plate cells to the completion of filling is very short, about a few hours, and stable. It can be installed.

The slit member and the water retaining chamber partition are steel structures made in the land yard, and the bottom slab concrete can be constructed reliably even in water by using special concrete.Therefore, the bottom level of the water retaining chamber is below the water level. Even so, highly reliable construction becomes possible and the water depth of the water in the basin can be deepened.

Since the slit member is already formed at the time of manufacturing the steel plate cell, it is not necessary to cut the cell steel plate underwater after the cell is placed, which makes it possible to shorten the construction period and improve the work safety.

Since the slit material and the partition wall of the water retaining chamber are made of steel and have a small weight, even if the filling material sinks, a large force is not applied to the cell steel plate.

[Brief description of drawings]

FIG. 1 is an island view of a steel plate cell breakwater constructed according to the present invention; FIGS. 2 (a) and 2 (b) are schematic longitudinal sectional views and partially cut views of the completed steel plate cell, respectively. Fig. 3 (a) and Fig. 3 (b) are longitudinal sectional views and transverse sectional views, respectively, of the steel sheet cell before construction; and Fig. 4 is a transverse sectional view of the steel sheet cell using a steel sheet pile partition wall. It is a figure. 10: Steel plate cell 12: Slit part 14: Water retaining chamber 16: Partition part 18: Top end surface

Front page continued (72) Inventor Sadami Murai, Asahi 1 Tsukuba, Ibaraki Prefectural Civil Engineering Research Institute, Ministry of Construction (72) Inventor Tae Yanagimoto 1-3-3 Otemachi, Chiyoda-ku, Tokyo Sumitomo Metal Industries Co., Ltd. Company (72) Inventor Osamu Iimura 1-3-3 Otemachi, Chiyoda-ku, Tokyo Sumitomo Metal Industries, Ltd. (72) Inventor Hideo Ogino 5 Yonban-cho, Chiyoda-ku, Tokyo Toa Construction Industry Co., Ltd. (56) References JP-A-59-165710 (JP, A)

Claims (1)

[Claims] 1. A construction method of a transmission type steel plate cell breakwater in which cylindrical steel plate cell structures are arranged in a single row or a plurality of rows at a required interval, and a slit portion is previously provided in at least a part of an outer upper portion. A cylindrical steel plate cell, which is provided with a partition wall made of steel in the direction of extension of the breakwater and a water-retaining chamber connected to the slit part, is cast on the sea bottom with the slit part facing the offshore side. Or, by installing the filling material up to the bottom surface level of the bottom plate of the water retaining chamber, and continuing the introduction of the filling material in the area behind the water retaining chamber and by constructing the bottom slab concrete of the water retaining chamber in water. A method of constructing a steel plate cell breakwater, characterized by constructing columnar steel cell structures.