JP7489286B2 - Underwater stockyard and underwater temporary support method - Google Patents

Description

The present invention relates to an underwater stockyard and an underwater temporary support method.

When constructing a floating structure on water (such as on the sea), there are several methods, including launching a float constructed on land using a semi-submersible barge, floating dock, dry dock, slipway, crane, etc., or constructing the float on a semi-submersible barge or floating dock on the water.
However, in some cases, it is not possible to secure a stockyard on land to temporarily store the floats after they have been fabricated. For this reason, temporary storage of the floats in ports near the fabrication yard is being considered.
In order to temporarily place a floating body on the water, it is common to moor the floating body using mooring members such as chains and wires extended from support members (pillars, piles, anchors, etc.) formed on the bottom of the water (see, for example, Patent Document 1). However, in order to stably moor a floating body, it is necessary to arrange the mooring members in multiple directions, so when mooring multiple floating bodies, it is necessary to stretch a large number of mooring members. On the other hand, in the limited space in a port, there is a risk that it is not possible to secure space to stretch a large number of mooring members. Furthermore, when the water is shallow, anchor mooring may be a large-scale project.
Also, as shown in Patent Document 2, for example, a temporary base (mound) may be formed by spreading riprap on the bottom of the water and placing components on this base, but if the top surface of the base formed by the riprap becomes uneven, the bottom surface of the components may be damaged. If the temporary base is formed from underwater concrete, the flatness of the top surface can be maintained, but it takes time and effort to flatten the top surface of the concrete underwater. Furthermore, if a base formed by spreading riprap on the bottom of the water and using it multiple times, it takes time and effort to maintain its function (shape) as a base.
Furthermore, there is a method of mooring the floating body to permanent piles (supports), but the piles must be strong enough to withstand external forces (horizontal forces) such as wave and wind pressure acting on the floating body, which requires large pile specifications (diameter and number of piles).As a result, there is a risk that the permanent piles will become an obstacle when moving the floating body.

JP 2017-43356 A Japanese Patent Application Laid-Open No. 10-237875

The objective of the present invention is to propose an underwater stockyard and an underwater temporary support method that can save space when temporarily placing a floating body underwater, ensure the soundness of the floating body when temporarily placed, and do not interfere with the maintenance and movement of the floating body.

The underwater stockyard for placing a float according to the present invention for solving the above problems includes a plurality of supports erected on the bottom of the water with a predetermined embedment, and a receiving member fixed to the heads of the supports. The receiving member has a main body having a planar shape larger than the bottom shape of the float, and a plurality of outer tubes provided according to the positions of the supports, and the heads of the supports are inserted into the outer tubes.
In addition, the underwater temporary support method of the present invention includes the steps of constructing the underwater stockyard underwater, placing the float in the vicinity of the underwater stockyard, and pouring water into the float and placing the float on the support member.
According to the underwater stockyard and the underwater temporary support method using the same, since the supports erected on the bottom of the water are used, there is no need to stretch mooring wires or the like in many directions (over a wide area). Furthermore, since the support surface of the float (the upper surface of the support member) can be finished smoothly, compared to a case where a base is formed from crushed stone or the like, the bottom surface of the float is less likely to be damaged. Furthermore, since the underwater stockyard is formed by combining the support member and the supports, the structure is simple. Furthermore, since the underwater stockyard is formed at a depth where the float can be placed when it is sunk, it is less likely to become an obstacle when moving the float.

The support member is preferably formed by combining steel materials, which makes it easy to install even underwater, easy to dismantle, and allows the steel materials to be reused.
Furthermore, if the underwater stockyard consists of a plate-like member having an inclined surface on the upper surface of the main body and arranged around the main body with its upper end protruding above the water surface, and is equipped with a guide for guiding the float to the upper surface of the receiving member when sinking the float, it will be easy to guide the float onto the underwater stockyard when sinking it.
Furthermore, if a friction-enhancing material is laid on the upper surface of the receiving member to increase the frictional force with the underside of the float, the float can be prevented from being swept away by changes in tide levels and tidal currents, etc.
In addition, it is preferable that the depth of the underwater stockyard from the water surface at high tide to the top surface of the receiving member is smaller than the total height of the float, and the depth from the water surface at low tide to the top surface of the receiving member is greater than the depth to the bottom surface of the float when towing it. This makes it easier to sink the float when towing it by a barge for temporary storage, and to re-float it when moving it, and shortens the time required.

The underwater stockyard and underwater temporary support method of the present invention allows for space saving when temporarily placing a floating body underwater, ensures the soundness of the floating body when temporarily placed, and does not interfere with the maintenance and movement of the floating body.

FIG. 1 is a perspective view showing an underwater stockyard according to an embodiment of the present invention. 1A and 1B are diagrams showing the state in which a floating body is placed in the underwater stockyard, in which (a) is a plan view and (b) is a side view. 4 is a flowchart showing an underwater temporary support method according to the present embodiment. FIG. 1 is a side view showing each construction stage of the underwater temporary support method, in which (a) is the pillar installation work in the stockyard construction process, (b) is the support member installation work, (c) is the float placement process, and (d) is the float placement process. 13A and 13B are diagrams showing another type of underwater stockyard, in which FIG. 13A and 13B are diagrams showing another type of underwater stockyard, in which FIG.

In this embodiment, when a floating structure (float 2) is provided at a predetermined position, an underwater stockyard 1 for temporarily storing the float 2 and an underwater temporary support method for temporarily storing the float 2 in the underwater stockyard 1 will be described. The underwater stockyard 1 is shown in FIG.
As shown in Fig. 1, the underwater stockyard 1 includes a plurality of support columns 3 and receiving members 4 fixed to the heads of the plurality of support columns 3. Fig. 2(a) shows a plan view of the underwater stockyard 1, and (b) shows a side view.

As shown in Fig. 2(b), the support pillars 3 are made of steel pipes that are driven into the water bottom GL and stand upright on the water bottom GL. The heights of the upper ends of the multiple support pillars 3 are uniform so that the horizontality of the receiving member 4 can be ensured. The support pillars 3 are driven vertically while ensuring a predetermined embedment depth.
As shown in Fig. 1, the receiving member 4 includes a main body 5 formed in a lattice shape by combining steel materials, and a plurality of external tubes 6 fixed to the main body 5 according to the positions of the supports 3. The main body 5 has a planar shape corresponding to the bottom shape of the float 2. The main body 5 of this embodiment has a rectangular shape in a plan view. In addition, as shown in Figs. 2(a) and (b), the outer shape of the main body 5 is larger than the outer shape of the float 2.
The outer tube 6 is made of a tubular member having an inner diameter larger than the outer diameter of the support 3, and is fixed to the main body 5. The head of the support 3 is inserted into the outer tube 6, whereby the receiving member 4 is attached to the head of the support 3.

The receiving member 4 is provided so that the depth from the water surface WL to its upper surface at high water level (high tide) is smaller than the overall height of the float 2. Moreover, the depth from the water surface to the upper surface of the receiving member 4 at low water level (low tide) is greater than the depth to the bottom surface of the float 2 when being towed. Moreover, the top level (height) of the receiving member 4 (main body 5) is set to a height at which the float 2 placed on the receiving member 4 is not affected (is less likely to be affected) by tidal fluctuations or waves.
As shown in FIG. 2B, a friction-increasing material 7 for increasing the frictional force with the bottom surface of the float 2 is laid on the upper surface of the receiving member 4 (main body 41). That is, the friction-increasing material 7 is interposed between the receiving member 4 and the float 2. The friction-increasing material 7 increases the static friction coefficient between the float 2 placed on the receiving member 4 and the receiving member 4, thereby preventing the float 2 from moving due to waves, wind, etc. Examples of materials constituting the friction-increasing material 7 include mats (sheets) made of asphalt or rubber-based materials. The friction-increasing material 7 covers the upper surface of the steel material constituting the main body 5. That is, the friction-increasing material 7 of this embodiment is arranged in a lattice shape similar to the planar shape of the main body 5.

Next, an underwater temporary support method for temporarily supporting the float 2 by the underwater stockyard 1 of this embodiment will be described. As shown in the flowchart of Fig. 3, the underwater temporary support method includes a stockyard construction process S1, a float arrangement process S2, and a float placement process S3.
The stockyard construction process S1 is a process of constructing underwater the underwater stockyard 1. In the stockyard construction process S1, a pillar driving operation S11, a receiving member installation operation S12, and a fixing operation S13 are performed.
Figure 4 (a) shows the pillar installation work S11. As shown in Figure 4 (a), in the pillar installation work S11, multiple pillars 3 are installed in the water bottom GL. The pillars 3 are installed in the water bottom GL while ensuring a predetermined embedment depth. The upper ends of the multiple pillars 3 are aligned to the same height.

In the receiving member installation work S12, the receiving member 4 is installed on the head of the support 3. Figure 4 (b) shows the receiving member installation work S12. As shown in Figure 4 (b), in the receiving member installation work S12, the receiving member 4 is lowered from above the support 3, and the outer tube 6 is placed over the head of the support 3 (the head of the support 3 is inserted into the outer tube 6).

In the fixing operation S13, the outer tube 6 is fixed to the head of the support 3. The method of fixing the support 3 and the outer tube 6 is not limited, and for example, they may be fixed using a jig or the like, or they may be fixed by filling a gap between the head of the support 3 and the outer tube 6 with a filler.
After the receiving member 4 is placed on the head of the support 3, the friction-increasing material 7 is placed on the upper surface of the receiving member 4 (see FIG. 4(c)). The friction-increasing material 7 may be placed on the upper surface of the receiving member 4 in advance.

In the float placement step S2, as shown in FIG. 4(c), the float 2 is placed near the underwater stockyard 1. FIG. 4(c) is a side view showing the float placement step S2. The float 2, while floating on the water surface, is towed by a tugboat or pushed by a pusher to be placed in a predetermined position. At this time, the float 2 is temporarily moored to the underwater stockyard 1 if necessary.

In the float placement step S3, as shown in FIG. 4(d), the float 2 is placed on the receiving member 4. FIG. 4(d) is a side view showing the float placement step S3. When placing the float 2 on the receiving member 4, ballast water is injected into the hollow float 2 to increase the weight of the float 2, thereby sinking the float 2. The amount of ballast water injected is an amount that ensures the stability of the float 2 against rocking caused by waves, etc. At this time, the float 2 may be guided to the upper surface of the receiving member 4 using a towing means, etc.

As described above, according to the underwater stockyard 1 and the underwater temporary support method using the same of this embodiment, since the supports 3 erected on the bottom GL are used, there is no need to stretch mooring wires in many directions (over a wide area). Therefore, it is possible to temporarily place multiple floating bodies 2 in a limited space such as a harbor.
Furthermore, compared to forming a foundation using crushed stone or the like, the support surface of the float 2 (the upper surface of the receiving member 4) can be finished smoothly, so that the bottom surface of the float 2 is less likely to be damaged.

In addition, since the underwater stockyard 1 is constructed by combining the support members 4 and the supports 3, it can be easily disassembled when removed and can be reused. In addition, since the support members 4 are constructed of a main body 5 formed by combining steel materials and a plurality of external tubes 6 provided according to the positions of the supports 3, the underwater stockyard 1 can be easily constructed even underwater by inserting the heads of the supports 3 into the external tubes 6.
In addition, since the underwater stockyard 1 is formed at a depth that allows the float 2 to be placed thereon when submerged, it is unlikely to become an obstacle when moving the float 2.
Furthermore, a friction-enhancing material 7 that increases the frictional force with the underside of the float 2 is laid on the upper surface of the receiving member 4, thereby preventing the float 2 from being swept away by changes in tide levels, tidal currents, etc.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and each of the above-described components can be appropriately modified without departing from the spirit of the present invention.
For example, the material constituting the support pillar 3 is not limited to steel pipes, but may be, for example, steel material such as H-shaped steel, or a precast member.
Furthermore, the support pillars 3 do not necessarily have to be vertical, but may be inclined.
The receiving member 4 does not necessarily have to be made of steel, but may be made of, for example, precast concrete.
Furthermore, the shape and dimensions of the main body 5 are not limited as long as it is capable of supporting the float 2 , and may, for example, have an outer shape smaller than the outer shape of the float 2 .
In addition, the underwater stockyard 1 may be provided with a guide 8 for guiding the float 2 to the upper surface of the receiving member 4 when the float 2 is sunk, as shown in Fig. 5 or Fig. 6. If the underwater stockyard 1 is provided with the guide 8, the float 2 can be easily guided onto the underwater stockyard 1 when it is sunk. The guide 8 may be, for example, a plate-like member erected on the upper surface of the main body 5, as shown in Figs. 5(a) and (b). It is preferable that the upper surface of the guide 8 is formed with an inclined surface for guiding the float 2 from the outside to the center of the receiving member 4. In addition, if the guide 8 is arranged to surround the periphery of the float 2, it is possible to prevent the float 2 from being swept away by high tides and high waves when a typhoon approaches.
6(a) and 6(b), the guide 8 may be a vertical member such as a steel pipe that is driven into the bottom GL so that its upper end protrudes above the water surface. In this case, the float 2 can be guided above the underwater stockyard 1 by sinking the float 2 in a state where it is attached to the guide 8.
The float 2 may be a completed floating structure, or may be a member constituting part of the floating structure.

Reference Signs List 1 Underwater stockyard 2 Floating body 3 Support 4 Receiving member 5 Main body 6 Outer tube 7 Friction increasing material 8 Guide

Claims (6)

An underwater stockyard for placing floating bodies,
A number of pillars erected on the bottom of the water;
A receiving member fixed to the heads of the plurality of posts ,
The receiving member has a main body having a planar shape larger than the bottom shape of the float, and a plurality of external intubations provided according to the positions of the columns,
An underwater stockyard, characterized in that the head of the support is inserted into the outer tube . The underwater stockyard according to claim 1 , wherein the main body is formed by combining steel materials. 3. The underwater stockyard of claim 1 or claim 2, characterized in that it is made up of a plate-like member having an inclined surface on the upper surface of the main body or a vertical member arranged around the main body with its upper end protruding above the water surface, and is provided with a guide that guides the float to the upper surface of the receiving member when the float is sunk. The underwater stockyard according to any one of claims 1 to 3, characterized in that a friction-increasing material is laid on the upper surface of the receiving member to increase the frictional force with the lower surface of the float. The depth from the water surface at high tide to the upper surface of the receiving member is smaller than the total height of the float,
5. The underwater stockyard according to claim 1, wherein the depth from the water surface at low tide to the top surface of said receiving member is greater than the depth from the water surface to the bottom surface of said floating body when being towed. A step of constructing the underwater stockyard according to any one of claims 1 to 5 underwater;
placing the floating body near the underwater stockyard;
and a step of pouring water into the float and placing the float on the support member.

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