JPS62182310A - Structure for icy sea - Google Patents

Abstract

PURPOSE:To reduce the cost of a structure for icy sea by a method in which a superstructure for working is supported on the upper end of a columnar leg erected on a sub-surface structure to be landed on the seabed, and an intermediate float with a ballast tank and a water supply and discharge device is set on the columnar leg in a vertically movable manner. CONSTITUTION:A superstructure 4 with an excavator for the seabed is supported on the upper end projected from the sea surface of a columnar leg 3 erected on a sub-surface structure 1 with a ballast tank 2. An intermediate float 5 with a ballast tank 6 and a water supply and discharge device is provided to the leg 3 in a vertically movable manner to make up a structure for icy sea. The structure is towed to a construction site, and water is supplied into the ballast tank 2 of the structure 1 to cause the structure 1 alone to settle under the condition that the float 5 is floated on the water surface. After the structure 1 is landed on the seabed 8, water is supplied into the tank 6, and the float 5 is sunk and set on the structure 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a structure for use in ice-covered seas for conducting seabed resource development work, etc. in ice-cold sea areas.

(Prior art) Fig. 9 shows a conventional monobod type ice-water structure, in which a lower structure (one pedestal (B) erected on Al) that touches the bottom of the seabed has a It is configured to support an upper structure (C) for excavation work that protrudes above the sea surface.

(Problems to be Solved by the Invention) The conventional monobod type water-sea structure described above has the advantage of not receiving huge ice loads because the portion that receives ice loads is small, but it has the following problems. There is.

(1) During towing, the buoyancy of the lower structure is low, resulting in deep water, which is disadvantageous when towing to the operating site.

(11) In the work of mounting the superstructure on the pedestal at sea during construction, the water line area is small, making it difficult to obtain sufficient stability.

(When the structure is placed on the bottom in the sea area where it is installed, the water line area is small and sufficient stability cannot be achieved.

In order to solve the above-mentioned problems, in conventional monobod ice-water structures, as shown in Fig. Ice structures with systems have been proposed, but
There were problems in that the structure was complicated and large, and the cost increased.

(Means for Solving the Problems) The present invention was proposed to solve these problems.
A working upper structure protruding above the sea surface is supported at the upper end of the pedestal, and an intermediate buoyant body equipped with a ballast tank and a water filling device is mounted on the pedestal so as to be able to rise and fall freely. This relates to structures for use in ice and sea.

(Function) Since the present invention is configured as described above, when installing the upper structure, the lower structure is seated on the seabed surface, and the pillars erected on the lower structure are mounted. Along the same line, the intermediate buoyant body is raised by adjusting the ballast tank and water filling device equipped on it, and is floated on the water surface to secure a sufficient water line area, and in this state, the upper structure is placed on the pedestal. Install.

When towing to an operating area, the ballast tank of the lower structure is drained and the lower structure floats to bring it into towing condition, and the ballast tank of the intermediate buoyant body is also drained to reduce the buoyancy of the buoyant body. To make the towing water shallower.

After arriving at the site, when installing the ice-water structure, water is poured into the ballast tank of the lower structure, and while the intermediate buoyant body is always floating on the water surface, only the lower structure is submerged in Step 4 to ensure stability during installation. improves.

After the lower structure has landed on the seabed, the intermediate buoyant body is submerged by pouring water into its ballast tank and installed on the lower structure.

(Effects of the Invention) According to the present invention, one
By mounting an intermediate buoyancy body equipped with a ballast tank and a water filling device along the main O-pillar so that it can rise and fall, it is possible to make the water shallower during towing, and it is also useful when constructing and installing structures for ice seas. In some cases, the water line area can be secured by an intermediate buoyant body, and the stability of ice-water structures can be improved without requiring a jacking system or a large amount of fixed ballast. Embodiment 5 (Embodiment) The present invention will be described with reference to the illustrated embodiment.

In Figures 1 and 2, (1) is the ballast tank (
2) is attached to the lower structure, and one pedestal (
3) is erected, and a superstructure (4
) is supported.

An intermediate buoyant body (5) is mounted on the pedestal (3) so as to be able to rise and fall freely, and a ballast tank (6) equipped on the buoyant body (5)
) and a water filling device (not shown), the buoyant body (5) is configured to move up and down along the pillar (3). Figures 3 to 8 show the process from construction to installation of the ice-water structure, with Figure 3 showing the structure pulled out from the construction truck, showing the lower structure (1). A pedestal (3) and an intermediate buoyant body (5) are mounted on top. Figure 4 shows the state immediately before the lower structure (1,) is lowered by pouring water into its ballast tank (2) and the upper structure (4) is mounted.
At this time, since the intermediate buoyancy body (5) is always floating on the water surface (7), a sufficient water line area can be secured, and therefore sufficient stability performance can be obtained.

Figure 5 shows the state of towing to the operating area, and shows the superstructure (4
), the lower structure (1) is floated by draining its ballast tank (2) and placed in towed condition. At this time, the buoyancy of the intermediate buoyant body (5) makes it possible to make the towing water shallow. Figures 6 to 8 show the installation process after arriving at the site.As shown in Figure 6, after arriving at the site, water is first poured into the ballast tank (2) of the lower structure (1), and the intermediate buoyant body ( 5) Only the lower structure (1) is submerged while keeping it floating on the water surface. Therefore, the stability performance of the structure during installation, which is a problem of monobod type offshore structures, has been greatly improved. According to the embodiment described above, this need is eliminated.

In Figure 7, after the lower structure (1) has touched the bottom of the seabed (8), water is poured into the ballast tank (6) of the intermediate buoyant body (5) to sink the buoyant body (5) and lower the lower part. 1 installed on the structure (1), FIG. 8 shows the state when the installation is completed.

According to the illustrated embodiment, the intermediate buoyant body (5) is mounted on one pedestal (3) connecting the upper and lower structures (4+(1) so as to be able to rise and fall freely), so that the The waterline during towing can be made shallow, and the intermediate buoyant body (5) can secure the waterline area during the construction and installation of the structure, without requiring a jacking system or a large amount of fixed ballast. It is possible to improve the stability of structures for ice seas, and according to the above embodiments, it is possible to construct high performance structures for ice seas at low cost.

Although the present invention has been described above with reference to embodiments, the present invention is, of course, not limited to such embodiments, and can be modified in various ways without departing from the spirit of the present invention. .

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of the ice-water structure according to the present invention, FIG. 2 is a plan view thereof, and FIGS. 3 to 8 are front views showing the process from construction to installation. Figures 9 and 10
Each figure is a front view showing each side of a conventional ice-water structure. (1,)... Lower structure (3)... Pillar (4
)...Superstructure (5)...Intermediate buoyant body (6
)... Ballast tank sub-agent Patent attorney Shige Okamoto 2 people outside the kiln Figure 1 Figure 2 Figure 10 Figure 4 Figure 6

Claims (1)

[Claims] A working upper structure protruding above the sea surface is supported at the upper end of one pedestal erected on a lower structure that touches the bottom of the seabed, and the pedestal is equipped with a ballast tank and a water filling device. A structure for use in icy seas characterized by having an intermediate buoyant body mounted so that it can be raised and lowered.