JP2661864B2 - Underwater caisson landing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method of landing an underwater caisson.

[0002]

2. Description of the Related Art When installing a caisson for a foundation used for an underwater bridge foundation or the like, a technique of installing the caisson after leveling the sea bottom is known.

[0003]

However, for example, when the marine conditions are severe or when the water depth is large, the work for leveling the seabed is extremely difficult and troublesome.

Accordingly, an object of the present invention is to provide an underwater caisson landing method in which an underwater caisson is installed without performing the work of leveling the seabed.

[0005]

According to the present invention, a tower is provided at the center, a projection is provided at the center of the lower portion of the caisson base, and a movable portion which is vertically expandable and contractible at each corner is provided. The underwater caisson, which is formed by folding a large number of cylindrical formwork around like a lantern, submerges in the water, bottoms out the central protrusion, and keeps the central tower in a vertical state. The movable part is extended and the bottom is locked, concrete is poured into the cylindrical cloth formwork, the base is surrounded by a column, and the inside of the column is filled to complete the foundation. It provides a method of landing an underwater caisson.

[0006]

[Explanation of operation and effect] In the underwater caisson landing method configured as described above, the lower part of the caisson, which is configured so that the tip of the central tower emerges above the water surface, is settled down until it reaches the bottom. With the central tower in a vertical state, the four movable sections are extended by, for example, water pressure or the like and locked at the bottom.

[0007] If concrete is poured into the cloth formwork around the lower part of the caisson, a column wall is formed between the sea floor and the periphery of the lower part of the caisson. Can be stably landed.

Therefore, there is no need to perform a difficult leveling work for the seabed.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

Before describing the method of landing an underwater caisson according to the present invention, an example of the apparatus will be described first.

In FIG. 1, a tower 1 is provided at the center of a base 2, and jacks 3, which are movable parts, are attached to the four corners of the base 2. A piston 3a is slidably attached to the jack 3 via shoes 3b and 3c.

A projection 1a is provided at the lower portion at the center. Referring to FIG. 2, a large number of cylindrical cloth frames 4 are folded around the base 2 like lanterns. Installed in. An air circuit 5 supplies compressed air to the jack 3 from an air supply source (not shown).

Hereinafter, the caisson landing procedure will be described with reference to FIGS.
This will be described with reference to FIG.

First, a caisson constructed as described above is manufactured, and the caisson is launched.

Then, the ship is towed to the site and gradually descends while pouring water into the base portion 2.

By continuing the above-mentioned descent, the projection 1 at the lower center is
a is landed on the seabed G (see FIG. 4, the symbol W indicates the sea surface).

Compressed air is supplied to the upper part of the piston 3a of the square jack 3 by the air circuit 5 so that the bottom of the tower 1 is vertical (see FIG. 5).

Next, concrete is poured into the cloth form 4 provided around the base portion 2 to form a column wall (see FIGS. 3 and 6). The inside is further filled with a filler to complete the foundation.

Therefore, the underwater caisson can be stably landed without performing the work of leveling the seabed.

[0020]

Since the present invention is constructed as described above, the underwater caisson can be landed without performing a difficult subsea leveling operation, and there is no troublesome and time-consuming leveling operation. Therefore, the construction period can be shortened and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a caisson embodying the present invention.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a diagram showing a state in which the caisson of FIG. 1 is landed on an inclined seabed.

FIG. 4 is a diagram showing a caisson landing operation procedure (1).

FIG. 5 is a view showing a caisson landing operation procedure (2).

FIG. 6 is a diagram showing a caisson landing operation procedure (3).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tower 2 ... Base part 3 ... Jack 4 ... Cloth formwork 5 ... Air circuit

Claims (1)

(57) [Claims] 1. A tower is provided at the center, a projection is provided at a central portion of a lower portion of a caisson base, a movable portion which is vertically expandable and contractible at each corner is provided, and a plurality of cylindrical portions are formed around the lower portion of the base. The underwater caisson where the cloth formwork is folded like a lantern is submerged in water, the central projection is settled, the central tower is kept vertical, the movable parts at each corner are extended, and the bottom lock Then, concrete is poured into the cylindrical cloth formwork, the base portion is surrounded by a column, and the inside of the column is filled to complete a foundation, whereby a submerged caisson bottoming method is provided.