JPS60138111A - Setting mechanism for bottom landing position of marine structure - Google Patents

Abstract

PURPOSE:To exactly set the position of pier stud for fixation by a method in which the lower end of the pier stud of a marine structure is shaped into a form of projected plug, plural vertical slits are provided in the periphery of the plug, and a recessed plug socket is fixed to the seabed. CONSTITUTION:A downwardly projected structure of plugs 2 are provided projectionally to the lower ends of the plural pier studs 1 of a marine structure. An upwardly recessed structure of plug sockets 4 having projections on its lower part are fixed to positions corresponding to the piers 1 of the seabed 3, in which the recessed structure is made up of a conical hole 12 and a vertical hole 11. The plug 2 is of a cylindrical form, having plural slits 8 provided axially at intervals. The lower ends of the pier studs can thus be exactly positioned and fixed and the deviation of the positions by earthquake, etc., can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bottom positioning mechanism for a marine structure suitable for positioning the marine structure on the seabed.

The present inventor previously proposed a bottom landing adjustment mechanism for marine structures in Japanese Patent Application No. 58-178953. This mechanism includes multiple pedestals extending from the marine structure and buoyancy tanks installed on each pedestal, and by adjusting the buoyancy of these buoyancy tanks, the marine structure is always kept horizontally attached to the seabed. It was groundbreaking.

An object of the present invention is to provide a bottoming positioning mechanism for a marine structure that is further improved from the mechanism of the prior application and made more practical.

In order to achieve such an object, the present invention is designed to efficiently, accurately, and precisely position a marine structure on the seabed so as to be able to effectively cope with tidal currents, submarine earthquakes, and the like.

EMBODIMENT OF THE INVENTION Hereinafter, the present invention will be described in detail based on embodiments shown in accompanying drawings.

In FIG. 1, numeral 1 indicates a pedestal extending from an offshore structure (not shown). Marine structures consist of buildings such as marine city buildings, marine airports, or oil stations. A number of pedestals 1 extend vertically from this marine structure, one of which is shown in FIG. Each of these pillars is provided with a buoyancy tank (not shown), and the buoyancy of each tank can be adjusted independently by supplying and discharging fluid. By adjusting the buoyancy of each tank, the lower end of the pedestal can be soft-knot-landed on the seabed. For details of the structure and operation of these marine structures, pillars and buoyancy tanks, please refer to the above-mentioned Japanese Patent Application No. 178953 filed by the present inventor.

A convex structure (plug) 2 is attached to the lower end of each pedestal 1, and a plurality of concave structures (outlets) 4 are fixed to the seabed 3 to support the plug. The plug 2 has a cylindrical shape made of, for example, steel, and is provided with a flange 5 at one end. This flange is connected to a flange 6 provided at the lower end of the pedestal 1 by a plurality of bolts 7 in a known manner. In the illustrated embodiment, the outer diameter d of the plug 2 is approximately 6 m, and the outer diameter of the pedestal 1 is approximately 1 m.
It is 0m. This plug is provided with a plurality of slits 8. These slits are spaced apart circumferentially of the plug and extend along the axial direction of the plug, as shown in FIGS. 1 and 3. In the embodiment shown, these slits are provided over a certain length in the middle of the plug, the lower ends of the slits not extending beyond the lower end of the plug. That is, the lower ends of these slits are not open. As another embodiment, the lower end of the slit may be extended to the lower end of the plug and opened, and a suitable ring may be fitted into the lower end of the plug to form the plug into a so-called Shinai-shape. In the illustrated embodiment, the slits are provided so as to divide the circumference of the plug into 16 equal parts. By providing such slits in the plug, a certain elasticity can be imparted to the rigid plug. That is, for example, when a large force is applied to the plug in the axial direction, the part of the plug where the slit is provided bends to bulge outward, preventing the large force from being directly applied to the pillar. force can be alleviated. Of course, this slit portion can return to its original straight state due to its elastic action unless the large force is removed.

Each outlet 4 is made of concrete or cast steel, for example, and has a protrusion 9 at its lower end that is inserted into the seabed 3. These outlets are fixed horizontally by driving their protrusions 9 into the seabed where the marine structure is to be installed by any means VC. A receiving portion 10 for accommodating the lower end of each plug 2 is provided at the upper end of these outlets. This receiving part consists of a vertical hole 11 into which the lower end of the plug 2 is smoothly inserted, and a conical hole 12 extending outward from the upper end of the vertical hole.

The lower end of each plug is inserted smoothly into the vertical hole 11, and the lower end surface of each plug is brought into light contact with the bottom surface of the vertical hole 11 by adjusting the buoyancy of the buoyancy tank provided with the pillar lK. (See Figure 1). A pressure sensor (not shown) may be installed between the lower end surface of the plug and the bottom surface of the vertical hole to indicate the degree of softness of the plug.

In the illustrated embodiment, the height h of the outlet is approximately 3 m, and the length of the vertical hole 11 is approximately 1 m (FIG. 1).

A substantially truncated conical projection 13 is provided at the center of the vertical hole 11 and extends from the bottom surface of the vertical hole. This protrusion is inserted into the central hole of the plug when the plug is inserted into the vertical hole and helps prevent unnecessary movement of the plug, primarily in the lateral direction.

In the above structure, first, a plurality of outlets 4 are fixed in advance to the seabed where the marine structure is to be installed. Then,
Insert the lower end of each of the plurality of plugs extending from the offshore structure into the vertical hole 11 of the corresponding outlet, and adjust the buoyancy of the buoyancy tank provided on the pedestal to insert the lower end of the plug into the vertical hole. Attach it to the bottom. In this way, the marine structure is positioned at a predetermined position in the ocean and will not be washed away by tidal currents VC or moved or tilted by earthquakes. In particular, when an earthquake occurs, the initial impact is alleviated by the slit portion of the plug, so that no large impact force is applied to the pillars, marine cities, etc. The impact of subsequent earthquakes can be avoided by making the entire structure slightly buoyant by draining the buoyancy tank as shown in Japanese Patent Application No. 58-178953. According to the present invention, the following effects can be achieved.

fi+ Outlet/plug type IT (7) for offshore structures
Since the structure is installed further on the seabed, the positioning and fixation of the pedestal can be ensured compared to the previous application in which the lower end of the pedestal is directly attached to the seabed, and the offshore structure is therefore prevented from being washed away by side currents. There is no risk of displacement due to earthquakes, etc. Furthermore, the position will not shift due to fluctuations in the buoyancy of the pillars.

(2) The slit portion of the plug can reduce the impact of an earthquake, and therefore will not have a negative impact on the residents of marine cities and other places located at the top of the pedestal.

(3) Electrical outlets installed horizontally on the seabed in advance) [Since the plugs are soft-attached, compared to the previous application in which the pillars are soft-attached to the seabed, the lower end of each plug is always maintained at equal pressure. can be brought into contact.

(41 In the above-mentioned prior application, the pressure sensor that detects the softness of the pedestal to the seabed was placed between the bottom end of the pedestal and the seabed, making it difficult to install the pressure sensor, but in the present invention The pressure sensor can be placed on the contact surface between the outlet and the plug, and therefore the pressure sensor can be installed very easily and accurately.

(5) In the above-mentioned prior application, a buoyancy tank was provided on the pedestal, so the bottom end of the pedestal could not be made thinner than necessary, but in the present invention, a plug is attached to the bottom end of the pedestal. This allows the plug to be made thinner, which reduces material costs.

(6) In the previous application, in which the lower end surface of the pedestal is directly attached to the seabed, the level of irregularities on the seabed was directly adjusted by the length of the pedestal having a buoyancy tank, so the production efficiency of the pedestal was extremely poor, but the present invention In this case, the length of the plug installed at the lower end of the pedestal can be adjusted, making it possible to repeatedly produce the same product when manufacturing each buoyancy tank and pedestal, making it suitable for tuna fish.

[Brief explanation of drawings]

Fig. 1 is a partially sectional elevational view showing an embodiment of the bottoming positioning mechanism for a marine structure according to the present invention, Fig. 2 is a partially sectional elevational view of an electrical outlet, and Fig. 3 is a partially sectional elevational view of a plug. It is a perspective view showing a slit part. 1. Pillar 2.. Plug 4. Outlet 8. Slit... 11. Vertical hole 12. Circular hole patent client Seihide Terai (4 others)

Claims (1)

[Claims] In a landing device for an offshore structure having a plurality of pedestals extending from the offshore structure and a buoyancy tank provided on each pedestal, a convex structure (plug) is added to the lower end of each of the pedestals. and a plurality of concave structures (outlets) fixed to the seabed, the lower end of each plug is positionable in a receptacle provided in each outlet, and the plugs are spaced apart around the circumference. A bottoming positioning mechanism for a marine structure, characterized in that a plurality of slits are provided extending in the axial direction of the structure.