JPS6237171B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an underwater structure suitable for constructing foundations for structures such as built islands, work yards, cofferdams, and breakwaters.

(Prior Art) Conventionally, the following methods have generally been adopted to construct underwater structures.

Construction of islands using embankments, construction methods using steel sheet piles, steel pipe sheet piles, and offshore platforms using membranes.

However, this method requires a legal slope of about 1:2 to 1:5, requires a large amount of earth and sand, and is time-consuming to construct. Since the method can only be reinforced at the top,
As the water depth increases, the sheet pile cross section becomes too large, increasing material and construction costs. After filling the membrane with sand, the hope is that water will be expelled and the water pressure from the outside will resist earth pressure and compact the sand. For this reason, the bottom is also surrounded by a membrane, making it impossible to excavate the inside or penetrate the ground with piles.

(Object of the invention) This invention was made by paying attention to the above-mentioned problems, and its purpose is to construct a structure with an extremely simple structure.
The object of the present invention is to propose an underwater structure that is easy to remove, is not affected by conditions such as ground and water depth, and can be used for foundation work such as sinking a caisson or driving piles.

(Structure of the invention) This will be explained below with reference to the illustrated embodiments.

This underwater structure is made of a bendable membrane material, and has a cylindrical body 1 with both ends open as an outer shell. A float 2 is attached to one end so that it floats on the water, and the other end has a slightly enlarged skirt-like opening, and an annular anchor 3 is attached to fix it to the bottom of the water. It is bent inside the cylindrical body 1. A plurality of annular reinforcing members 5 are attached at predetermined intervals in the direction of the outer circumferential hoop of the cylindrical body 1 arranged in this manner, and the inside thereof is filled with sand 6 to form a cylindrical mound underwater structure. There is. This structure is anchored to an anchor 7 sunk on the bottom of the water with a rope 8 to improve installation stability, and a top annular reinforcing member 5' is installed around the upper edge to maintain the shape, and the top surface is paved. The surface 9 was designed to improve workability.

The membrane material used in this invention is one having high tensile strength and foldability, such as rubberized cloth, synthetic fiber fabric, nonwoven fabric, and synthetic resin sheet laminate. As the annular reinforcing material, a material having high tensile strength such as steel, a polymer composite material such as FRP, or a synthetic fiber composite material is used. However, the top annular reinforcing member 5' and the annular anchor 3 for fixing the lower end must be made of steel or the like having high rigidity to maintain their shape.

This structure has a cylindrical shape, but the diameter of the lower end is usually 1.0 to 1.5 times the diameter D of the top. The annular reinforcing members are arranged at vertical intervals of 1/5 to 1/10 of the top diameter D to resist the spreading pressure of the introduced sand.

(Function) This underwater structure has the above configuration. The inside of the cylinder is filled with sand, and pressure (earth pressure) is generated by the sand to force the cylindrical body to expand. This pressure acts as a very large tensile force for large diameters, but because the annular reinforcement is attached in the direction of the hoop, even relatively thin membrane materials can withstand this tensile force. The bottom of the structure is open and directly under water, so foundation work for the structure such as caisson settling and pile driving can be carried out. In addition, the structure is simple, the slope is small, and only a relatively small amount of sand needs to be input and discharged, and there is no need to remove internal water, so it can be easily and quickly constructed or removed. Furthermore, it does not need to be rooted in the ground, is not affected by the hardness or softness of the ground, unevenness, etc., and is not affected by water depth.

To construct this structure, annular reinforcing members 5 are attached at predetermined intervals to a cylindrical body 1 made of membrane material, folded into a bellows shape, and transported to the site. Here, a float 2 is attached to one end to float it on the water surface, and after locking and fixing it to an anchor 7 sunk outside the installation position, the folded cylindrical body 1 is pulled down into the water,
An annular anchor is attached to the lower end and fixed to the water bottom 4. At this time, the lower edge is bent inward along the ground surface of the water bottom 4 to prevent sand from flowing out and to strengthen the bottom ground against sliding failure. In this state, sand is poured into the interior and the top is paved or otherwise finished.

Removal can be easily carried out by reversing the above steps. At this time, the cylindrical body and other members forming the outer shell can be used repeatedly.

Furthermore, if this structure is used to build a caisson island, for example, a large lateral pressure will be applied when it is submerged, which is difficult to deal with with other construction methods, but with this structure it is possible to strengthen the reinforcing material. can be easily dealt with.

(Effects of the Invention) The present invention is as described above, and this underwater structure provides the following effects. Built with an extremely simple structure,
It is easy to remove and can be constructed at low cost regardless of conditions such as ground and water depth. Capable of constructing foundations for structures such as sinking caissons and driving piles.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional view of an underwater structure according to an example. DESCRIPTION OF SYMBOLS 1... Cylindrical body, 2... Float, 3... Annular anchor, 4... Bottom of water, 5... Annular reinforcement material, 5'...
...Top annular reinforcement, 6...Sand, 7...Anchor,
8...rope, 9...paved surface.

Claims (1)

[Claims] 1 A float is attached to one end of a cylindrical body made of a bendable membrane material and open at both ends to float it on the water. An underwater structure characterized by having annular reinforcements arranged at predetermined intervals and a cylindrical body filled with earth and sand.