JPS5920417Y2 - Spud tank for offshore platform support legs - Google Patents

Description

[Detailed description of the invention] This invention relates to a spud tank for supporting legs of an offshore work platform. This prevents the undersea ground necessary for the above operations from being scoured, thereby increasing safety by preventing serious accidents such as cave-ins and overturning of offshore work platforms on the spy and idle tanks. Our goal is to provide spud tanks.

For example, in an elevating offshore work platform (such as a jack-up type oil rig), the work platform is configured to be able to rise and fall relative to its support legs, and the work platform, support legs, etc. A spud tank is provided to support the entire weight of the

A spud tank is composed of a hollow body with a certain extent in order to disperse the load acting on the seabed ground when it is seated. Next, let us consider how the spud tank 3, which has a downward projecting portion 2 at the center of the bottom plate 1, is seated on ground of various properties.

As shown in FIG. 1, when the seabed ground 4 is a hard ground 4A such as a coral reef or bedrock, the ground 4A of the spud tank 3 has sufficient bearing capacity.
There is little penetration into the overhanging part 2.
Only one person is seated.

In this case, the phenomenon in which the ground around the spud tank 3 is dug up by tidal currents or the like, ie, scouring, does not occur because the ground 4A itself is hard, and it can be considered that there is no danger.

As shown in Figure 2, if the seabed ground 4 is sandy 4B, the spud tank 3 will sink into the tank a lot, and since the sandy 4B itself does not have scour resistance, spuds may be affected by tidal currents, etc. The sand layer B around the cut-in part of the tank 3 is washed away, and scouring is likely to occur in this part.

When the seabed ground 4 is a soft clay layer 4C as shown in FIG. 3, almost the entire spud tank 3 is embedded into the clay layer 4C.

In this case, it takes a long time (period) for the clay layer below spud tank 3, which supports the largest load, to be scoured.
Therefore, scouring is not a problem in practice.

From the above, it is necessary to take measures to prevent scouring in the situation shown in Figure 2.

It is known that scouring is more likely to occur when a spud tank is placed in a uniform tidal current, and by disturbing this tidal current and making it turbulent, the occurrence of scouring can be suppressed.

The present invention has been devised in view of the above, and examples thereof will be described below with reference to FIGS. 4 to 7.

In FIG. 4, 10 is a top plate and 11 is a bottom plate.

The upper surface plate 10 has a polygonal cap shape, that is, in the illustrated example, a regular hexagonal shape when viewed from above, and is configured such that the center portion is higher and the upper surface plate 10 is gradually lower as it approaches the periphery.

This top plate 10 has ridges 10 at six equal angle intervals.
A. It has a flat part 10B between each ridge part 10A.

The lower plate 11 has a similar shape in plan view to the upper plate 10,
It is constructed such that it gradually becomes higher as it approaches the periphery, and has a downward projecting portion 12 having a similar shape in plan view at the center thereof.

The upper surface plate 10 and the lower surface plate 11 are connected by a peripheral edge plate 13 whose peripheral edges and holes are arranged in a hexagonal cylinder shape.

As illustrated in FIG.
Ribs 16 and the like are provided along the top plate 1.
0, the bottom plate 11 and the peripheral plate 13 are reinforced.

A predetermined arrangement state (
An example is shown in FIG. 7), in which a number of recesses 17 are formed.

As clearly shown in FIGS. 5 and 6, in the illustrated example, the concave portion 17 is configured as a quadrangular pyramid-shaped recess.

A guide block 18 is fixed on the top wall 17A of the concave portion 17, and a through hole 19 is formed in the guide block 18 and the top wall 17A.

A retractable rod 20 is provided through the through hole 19, and an earth pressure receiving plate 22 is hinged to the tip of the retractable rod 20 by a universal joint 21.

The earth pressure receiving plate 22 has a rectangular shape, the universal joint 21 is coupled to the center thereof, and the earth pressure receiving plate 22 can be housed inside the recessed part 17 .

In order to maintain a good pressure receiving state when stored,
An inclined surface 22A is formed on the outer periphery of the Tonosho receiving plate 22, corresponding to the side wall 17B of the recessed portion 17.

In addition, a stopper 2 is provided at the upper end of the retractable rod 20 to prevent it from falling out.
3 is fixed.

A compression spring 24 is interposed between the ceiling wall 17A and the earth pressure receiving plate 22, and the compression spring 24 always urges the earth pressure receiving plate 22 in a direction to protrude from the concave portion 17 to the outside.

25 is a support leg, which is constructed by framing three cords 25A, and the above-described spud tank is attached to the lower end of the support leg.

According to the above, when the spud tank is seated on the seabed ground 26 and there is a clearance between the seabed ground 26 and the lower plate 11, as shown in FIG. The plate 22 protrudes to the outside of the concave portion 17,
It comes into contact with the submarine ground 26.

At this time, the earth pressure receiving plate 22 follows the slope of the seabed ground 26 due to the action of the universal joint 21.

In this state where the earth pressure receiving plate 22 protrudes from the concave portion 17, the compression spring 24, the retractable rod 20 and the earth pressure receiving plate 22
This helps to disrupt the current and prevents scouring.

As shown in FIG. 5, when there is no clearance between the seabed ground 26 and the bottom plate 11, that is, when the bottom plate 11 is embedded in the seabed ground 26, the earth pressure receiving plate 22 receives earth pressure, resulting in compression. The spring 24 is contracted by the earth pressure, and the earth pressure receiving plate 22 is eventually stored in the recessed part 17.

At that time, the earth pressure acting on the Tonosho receiving plate 22 is caused by the compression spring 24
and the recess side wall 17B, and the retractable rod 20
serves to accurately guide the earth pressure receiving plate 22 into the concave portion 17.

In addition, if the submarine ground is hard ground such as a coral reef,
The overhanging portion 12 rests on the seabed ground or is only slightly embedded, and the seabed ground itself has scour resistance, so scour is unlikely to occur. becomes even more complete.

In addition, in the case of extremely flexible seabed soil, if almost the entire spud tank is submerged (see Figure 3), ζ
Scour is not a problem as it is on slopes.

In this case, when pulling out the spud tank, its top plate 1
There is an advantage that 0 is in the shape of a hat.

That is, at the time of pulling out, the earth and sand covered on the top plate 10 slides down along the top plate 10 as the spud tank is pulled up, so that the force required to pull it up is minimized.

As is clear from the above explanation, according to the present invention, if there is a clearance between the bottom plate of the spud tank and the seabed ground when it is seated, it has the same effect as if there were many protrusions within that clearance. Since this is performed by the Tonosho receiving plate, the compression spring, the retracting rod, etc., it is possible to effectively prevent the tidal current from being disturbed and the occurrence of scouring.

[Brief Explanation of the Drawings] Figures 1 to 3 are explanatory diagrams of how the spud tank 3 is seated on various seabed grounds 4, Figures 4 to 7 illustrate embodiments of the present invention, and Figure 4 shows how it is used. FIGS. 5 and 6 are enlarged cross-sectional views of essential parts in the used state, and FIG. 7 is a bottom view.

Claims (1)

[Scope of utility model registration request] A number of recesses are provided in the lower plate, and an earth pressure receiving plate is provided at the tip of a retractable rod that penetrates the walls of these recesses, and that moves in and out between the inside and outside of the recess as the rod moves in and out. A spud of a supporting leg for a marine work platform, which is hinged and has a compression spring exposed in water and contracted by a soil pressure acting on the earth pressure receiving plate, interposed between the upper pressure receiving plate and the recessed wall. tank.