JP5190329B2 - Support floating body for tension mooring floating body, and towing method and installation method of tension mooring floating body using the same - Google Patents

Description

  The present invention relates to a support floating body for a tension mooring floating body that can support towing work or installation work at the time of towing and installation of a tension mooring floating body used as a pedestal of a wind power generator and the like, and a tension mooring using the same The present invention relates to a floating body towing method and installation method.

  Regarding wind power generation, a proposal has been made to install a tension mooring floating body (TLP: tension leg platform) in a relatively deep water area on the coastal continental shelf, and to mount a device such as a wind power generator on the tension mooring floating body. I'm starting. For example, as shown in FIG. 10, the floating body 12 on which the pedestal 11 of this wind power generator is mounted has one or more (four in FIG. 10) tension mooring lines 13 called tendons attached to the floating body 12. And anchored to a fixing subsidence member 14 such as an anchor provided on the bottom 2 of the seabed, lake, river, or the like.

  In general, the tension mooring floating body 1X as shown in FIG. 10 is not limited to the wind power generator, but the ballast water is injected into the ballast tank of the floating body 12 or the ballast is loaded, so that the draft of the floating body 12 is drawn. In a state where it is deepened and submerged than in the installation state, it moves onto the fixed bottom member 14 installed in the preset water area in advance. After the movement, the upper end of the tension mooring line 13 is coupled to the upper mooring part 15 c of the floating body 12, and the lower end of the tension mooring line 13 is coupled to the lower mooring part 14 c of the fixing bottom member 14.

  After the coupling, the buoyancy of the floating body 12 is set to a preset buoyancy by discharging the ballast water or removing the ballast while paying attention to the inclination of the floating body 12 on which the upper structure 11 is mounted. Furthermore, the length of the tension mooring lines 13 is changed to adjust the inclination of the upper structure 11 and the magnitudes of the tensions T1 to T4 of the tension mooring lines 13. In this installation, the tension mooring line 13 is set in advance so that the tension mooring floating body 1X does not shake up and down, laterally tilt, and vertically tilt in the waves, and the movable range within the horizontal direction falls within the allowable range. The applied initial tensions T1 to T4 are applied and moored (see, for example, Patent Documents 1 and 2).

  Further, in the case of mounting a wind power generator that does not require a large area for mounting the superstructure, a columnar body (center column) 12a penetrating the water surface as shown in FIG. An upper end side of a plurality of tension mooring lines 13 is fixed to a floating body 12 having a submerged buoyancy body (pontoon) 12b connected to the lower part of 12a, and a lower end side of the tension mooring lines 13 is fixed to the bottom 2 It has been proposed that the tension mooring cable 13 is connected to the lower anchoring portion 14c of the bottom sinking member 14 and tension is applied to the tension mooring cable 13 to hold the tension mooring floating body 1Y in position (see, for example, Patent Documents 3 and 4). .

  In a tension mooring floating body 1Y called a “mini tension leg platform (mini TLP)” composed of a floating body 12 having a columnar body 12a penetrating the water surface and a submerged buoyant body 12b connected to the columnar body 12a, The tension mooring line 13 is moored to the upper mooring part 15c of the submerged buoyancy body 12b at the water depth D. Since the tension mooring floating body 1Y has only the columnar body 12a penetrating the water surface after installation, the influence on the tension of the tension mooring line 13 due to fluctuations in the tide level and up and down of the water surface due to waves is reduced.

  However, when the tension mooring floating body 1Y is not towed or installed when the tension mooring floating body 1Y is installed, the static restoring force is remarkably small because only the columnar body 12a penetrates the water surface. There is a problem that the stability performance is very bad. Therefore, the use of a crane is indispensable for maintaining the posture of the tension mooring floating body 1Y during towing and installation.

  In this case, even a “mini-TLP” equipped with a wind power generator has a large power generation capacity and can exceed 1000 tons in weight, so the crane to be used must be a large offshore crane. This large offshore crane has a small number of ships in the market and is necessary from the time of towing until the completion of installation, so that the period of use of the large offshore crane becomes long. Therefore, it is difficult to adjust the schedule of towing and installation work, and there is a problem that costs increase.

In the “mini TLP” of the prior art, since the upper mooring portion 15c of the tension mooring line 13 is in the water, the work for attaching the tension mooring line 13, the tension adjustment work, the maintenance check work, and the like are work in the water. For this reason, the workability is poor and the work time is long, so the cost for these work increases. In addition, when the lower mooring part sinks unequally due to an earthquake or the like after installation, it is necessary to adjust the length of the tension mooring line 13 with respect to this unequal subsidence. Since it is submerged, there is a problem that it is necessary to work underwater.
Japanese Patent Laid-Open No. 1-145292 Japanese Patent Laid-Open No. 4-197887 Japanese Utility Model Publication No. 64-2692 JP 2005-69025 A

  Therefore, as shown in FIG. 1, a plurality of floating bodies 12 having columnar bodies 12 a penetrating the water surface 3 and submerged buoyancy bodies 12 b and a plurality of lower mooring portions 14 c on the fixing subsidence member 14 installed on the bottom 2 are provided. In a tension mooring floating body 1 that is connected by a tension mooring line 13 and holds the position by applying tension to the tension mooring line 13, a mooring columnar body 12c having a water surface penetrating buoyancy portion is connected to a submerged buoyancy body 12b. The tension mooring floating body 1 which fixes and fixes the upper end side of the tension mooring line 13 to the upper mooring part 15c provided above the water surface of the mooring columnar body 12c is considered.

  This tension mooring floating body 1 can increase the static restoring force of the tension mooring floating body 1 during towing and installation to ensure stability, thereby reducing the capacity and frequency of use of large offshore cranes required. Moreover, it can be made unnecessary depending on the weather and sea conditions in the water area. In addition, the installation work and the length adjustment work of the tension mooring line 13 can be performed above the water surface 3 during and after installation.

  However, even in the tension mooring floating body 1 shown in FIG. 1, since the center of gravity is at a relatively high position, the restoring force against the inclination is not sufficient, and in particular, after the construction of the tension mooring floating body 1, the floating that is not loaded with ballast water When shifting from a state to a semi-submersible state for installation by tension mooring, there is a risk that the tension mooring floating body 1 will not be able to maintain a self-supporting state as it is. However, there is a problem that anxiety remains to make it unnecessary.

  In particular, when the tension mooring floating body has a semi-submersible floating structure, it is likely to be in an unstable state in which it is easy to fall over in the middle of deepening the draft when transitioning from the floating state to the semi-submersible state Therefore, it is important to stabilize the posture of the tension mooring floating body in this intermediate stage.

  The present invention has been made in view of the above situation, and its purpose is to tow and install a tension mooring floating body by means of a supporting floating body temporarily arranged at least during towing or installation work. An object of the present invention is to provide a support floating body for a tension mooring floating body that can be sufficiently supported, and a towing method and an installation method for the tension mooring floating body using the floating body.

The support floating body for the tension mooring floating body for achieving the above object is arranged around the central columnar body penetrating the water surface, and the upper end side end of the tension mooring line is fixed. At least one of the towing operation and the installation operation to support the towing operation or the installation operation of the tension mooring floating body having a connecting column for connecting the central columnar body and the anchoring columnar body. The support floating body is arranged along the tension mooring floating body, and the support floating body is relatively fixed to the tension mooring floating body and can be relatively moved up and down with respect to the mooring columnar body. In such a state, it is configured to be arranged along the mooring columnar body.

  This support floating body is arranged along the mooring columnar body in a state in which it can move up and down relatively with the mooring columnar body (usually called a corner column), that is, in a slidable state. Although it does not affect the buoyancy of the mooring columnar body, that is, the vertical movement, the mooring columnar body is restrained from tilting and tilted together with the mooring columnar body. Therefore, the inclination of the anchoring columnar body can be suppressed by the support floating body, the restoring force can be secured, and the posture of the tension mooring floating body can be stabilized. In other words, by arranging this support floating body, it is possible to suppress the heel (lateral inclination) and trim (vertical inclination) of the tension mooring floating body.

  In particular, when the tension mooring floating body is formed with a semi-submersible floating structure, it is easy to fall down in the middle of deepening the draft when shifting from the floating state in the submerged buoyant body part to the semi-submerged state at the time of installation. Although it becomes unstable, this supporting floating body can remarkably increase the restoring force related to the inclination of the tension mooring floating body with respect to the water surface, so that the posture of the tension mooring floating body at each stage when this draft is increased is stabilized. Can be prevented.

  As a result, the tension mooring floating body can be stabilized and the towing can be prevented in the towing work and installation work of the tension mooring floating body. Can be made unnecessary.

  In addition, since the support floating body is removed from the tension mooring floating body except during towing and installation, the support floating body can be repeatedly used when many tension mooring floating bodies are installed. As a result, the cost of towing and installation per unit of the tension mooring floating body can be reduced.

  This support floating body is constructed so as to float on the water surface, and if it is provided over the vicinity of the top and bottom of the water surface penetrating portion of the mooring columnar body, the support floating body has a portion on the water surface. Further, it is preferable because the suppression control of the inclination is easy. In addition, the structure that can move relatively up and down is easily configured, for example, by providing a plurality of rotating bodies (for example, elastic rollers) that abut on the guide guides of the anchoring columnar body on the support floating body side. it can. The rotating body is preferably configured so that it can be moved in the horizontal direction using a spring or the like and can be adapted to changes in the gap so as to cope with manufacturing errors or deflection of the floating body.

  The support floating body for the tension mooring floating body, wherein the tension mooring rope winding system for tension mooring the tension mooring floating body, and the support floating body temporarily moored in a state of being arranged along the tension mooring floating body A temporary mooring system, a system for adjusting the ballast of the support floating body itself, a power supply system for the tension mooring floating body, a power supply system for the support floating body, or some combination thereof It is configured with a work support system.

  On the tension mooring floating body side, some or all of the incidental facilities used only during towing or only during installation work are provided on the support floating body side, so that the towing and installation work of the tension mooring floating body can be sufficiently supported. Thereby, a part or all of the incidental facilities on the side of the tension mooring floating body can be omitted, and the cost of the entire apparatus of the tension mooring floating body can be reduced.

  In the support floating body for the tension mooring floating body, the support floating body has a concave portion into which the mooring columnar body enters, and the working floating body is arranged along each of the mooring columnar bodies, The supporting floating body is configured to include a coupling member that couples the working floating body, and at the time of work support, the working floating body disposed along each mooring columnar body is coupled and integrated by the coupling member. In addition, after the work support is completed, the coupling member is separated from the work floating body, and the work floating body is separated from the tension mooring floating body.

  According to this configuration, since the working floating body has the concave portion into which the mooring columnar body enters, the working floating body has more portions along the mooring columnar body, and the working floating body is unlikely to be detached from the mooring columnar body. In addition, the inclination of the mooring columnar body can be easily suppressed, and the restoring force of the tension mooring floating body can be reinforced. The recesses are provided so as to come into contact with each other via, for example, a rotating body such as an elastic roller so as to be relatively vertically movable from the outside or inside of the mooring columnar body.

  Further, since the support floating body is integrally configured by connecting the work floating body with a detachable connecting member, the attachment to the tension mooring floating body is facilitated. In particular, when the concave portion is surrounded from the outside of the mooring columnar body, the workability of the integrated work is improved as compared with the case where the concave portion is surrounded from the inner side of the mooring columnar body. On the other hand, when the recess is surrounded from the inside, the occupied area in the horizontal plane of the support floating body can be made smaller than when the recess is surrounded from the outside. And tow on narrow routes. Thereby, the support floating body can be arranged with a small amount of work, and the towing and installation work of the tension mooring floating body can be sufficiently supported.

In addition, the towing method of the tension mooring floating body for achieving the above-described object is a central columnar body penetrating the water surface, and the upper end side end of the tension mooring line is fixed around the central columnar body. When towing a tension mooring floating body having a connecting column that connects the mooring columnar body and the central columnar body and the mooring columnar body, a support floating body for the tension mooring floating body is attached to the tension mooring floating body. It is a method of towing in a state where they are arranged.

  According to this towing method, when the tension mooring floating body is towed, the support floating body is towed in a state of being arranged along the tension mooring floating body, so that the inclination of the mooring columnar body can be suppressed by the support floating body, and the restoring force Can be secured and the posture of the tension mooring floating body can be stabilized. As a result, when the tension mooring floating body is towed, the posture of the tension mooring floating body can be stabilized and the fall can be prevented, so that support by a large offshore crane can be made unnecessary. Thereby, the towing work of a tension mooring floating body can fully be supported.

In addition, the tension mooring floating body installation method for achieving the above-described object includes a central columnar body penetrating the water surface, and the upper end side end portion of the tension mooring line is fixed around the central columnar body. In the installation of the tension mooring floating body having the columnar body for mooring and the connecting member for connecting the central columnar body and the columnar body for mooring, the support floating body for the tension mooring floating body is used.

  According to this installation method, when the tension mooring floating body is installed, the installation work is performed in a state where the support floating body is arranged along the tension mooring floating body, so that the inclination of the mooring columnar body is suppressed by the support floating body. The installation work can be performed in a state where the restoring force is secured and the posture of the tension mooring floating body is stabilized. As a result, during the installation work of the tension mooring floating body, it is possible to stabilize the posture of the tension mooring floating body and eliminate the need for support by a large offshore crane for preventing the fall. Thereby, the installation work of the tension mooring floating body can fully be supported. Further, since the support floating body can also be used as a work table, the work area of the mooring columnar body can be reduced.

  In the installation method of the tension mooring floating body, the support floating body is formed with a temporary mooring system for temporarily mooring the tension mooring floating body, and when the tension mooring floating body is installed in the temporary mooring system, In the water area where the mooring floating body is installed, the temporary mooring system sinks the fixed bottom member to which the lower end of the tension mooring line is moored to the sea floor, and temporarily supports the floating body for support arranged along the tension mooring floating body. Then, mooring is performed using the tension mooring line, and after mooring using the tension mooring line, the temporary mooring is released.

  According to this method, the temporary mooring of the support floating body is performed under the effect of preventing the fall by the support floating body, so that the temporary floating can be easily moored without fear of falling, and further, the temporary floating provided on the support floating body side. Because the mooring system lowers the anchoring subsidence member such as an anchor while supporting its weight, there is no need for facilities such as a winch to lower the anchoring subsidence member to the bottom of the water on the tension mooring floating body side or work ship side. Become.

  According to the support floating body for the tension mooring floating body of the present invention, and the towing method and installation method of the tension mooring floating body using the same, during towing or installation of the tension mooring floating body, during towing or installation work The support floating body temporarily disposed at least on one side can sufficiently support the towing and installation work of the tension mooring floating body.

  In particular, the tension floating mooring body is arranged by being arranged along the mooring columnar body so that the supporting floating body can move up and down relatively with respect to the mooring columnar body, that is, in a state where it can slide in the vertical direction. It is possible to generate a restoring force against the inclination of the. Thereby, the inclination of the mooring columnar body can be suppressed to stabilize the posture, and the risk of rollover can be significantly reduced. As a result, in the towing work and installation work of the tension mooring floating body, the support by the large offshore crane can be eliminated, and the cost can be reduced.

  Hereinafter, a support floating body for a tension mooring floating body according to the present invention and a towing method and an installation method of a tension mooring floating body using the same will be described with reference to the drawings. Here, in particular, a tension mooring floating body in which a wind power generator is mounted on an upper structure supported by the floating body will be described as an example. However, the present invention is not limited to the wind power generator, and the upper structure includes an oil well drilling device, and the like. The present invention can also be applied to a tension mooring floating body equipped with a plant or a measuring device.

  As shown in FIG. 3, the support floating body 20 for the tension mooring floating body according to the embodiment of the present invention is towed to the tension mooring floating body (mini tension leg platform) 1 as shown in FIG. Alternatively, in order to support the installation work, at least one of the towing and the installation work can be moved up and down relative to the anchoring column 12c of the tension mooring floating body 1 along the tension mooring floating body 1 Is arranged along the columnar body 12c for mooring.

  First, the tension mooring floating body 1 in which the support floating body 20 is used will be described. As shown in FIGS. 1 and 2, the tension mooring floating body 1 anchors the floating body 12, a floating body 12 for supporting the upper structural body 11, a superstructure 11 on which the wind power generator 10 is mounted. A number of tension mooring lines 13 called tendons, and a number for fixing the tension mooring lines 13 to the bottom 2 of the seabed, lake bottom, river bed, etc. And the bottomed member 14 for use.

The floating body 12 supports the weight of the upper structure 11 with buoyancy and maintains the upper structure 11 at a preset height above the water. The floating body 12 includes a central columnar body 12a formed of a cylinder or a polygonal column for supporting the upper structure 11, and three or more (3 in FIG. 1) extending radially from the lower portion of the central columnar body 12a. And a submerged buoyant body (connecting member) 12b formed of a columnar body. The central columnar body 12a is called a center column, and the submerged buoyancy body 12b is called a pontoon. The central columnar body 12a and the submerged buoyancy body 12b have a hollow structure and are configured to generate buoyancy using steel, prestressed concrete (PC), or the like. In addition, as shown in FIG. 6, the submerged buoyancy body 12b is provided with a ballast tank 12ba. Further, instead of forming the submerged buoyancy body 12b with a hollow structure, a part or all of the submerged buoyancy body 12b may be formed with a truss structure.

As shown in FIG. 1, a mooring columnar body 12c called a corner column is connected to the end opposite to the central columnar body 12a of the submerged buoyancy body 12b. The mooring columnar body 12c is configured to have a water surface penetrating buoyancy portion, and is provided so that a part of the upper portion protrudes above the water surface 3 when the tension mooring floating body 1 is installed.

  As shown in FIGS. 1 and 2, the mooring columnar body 12c is formed of a columnar buoyant body having a hollow portion 12h, and the upper portion of the tension mooring cord 13 is passed through the hollow portion 12h, so that the tension mooring cord. The upper end portion of 13 is attached to and fixedly supported by an upper mooring portion 15c provided at a position above the water surface of the mooring columnar body 12c. This is for the purpose of adjusting the length of the tension mooring line 13 and its tension force in the air instead of in the water. This facilitates installation work and inspection and maintenance work, and reduces these costs. The horizontal cross-sectional shape of the mooring columnar body 12c may be a polygon such as a quadrangle, a polygon with rounded corners, etc. in addition to the circle shown in FIG.

That is, the tension mooring floating body 1 includes a central columnar body (center column) 12a penetrating the water surface, a mooring columnar body (corner column) 12c disposed around the central columnar body 12a, and a central columnar body 12a. A submerged buoyancy body (pontoon) 12b, which is a connecting member for connecting the mooring columnar body 12c, is provided.

According to this structure, by providing the mooring columnar body 12c so as to pass through the water surface 3 and reach the upper side of the water surface 3, the static surface restoring force is newly increased by the water surface portion 12d of the mooring columnar body 12c. Occur. With respect to this restoring force, the upper mooring portion 15c is separated from the central columnar body 12a in a plan view, so that the moment lever relating to the inclination of the upper structure 11 is increased, so that the fall acting on the floating body 12 and the upper structure 11 The amount of change in tension of the tension mooring line 13 caused by the moment is reduced.

  The greater the distance, the larger the moment lever, so a greater restoring force can be obtained with the same water surface area. However, since there is a limit in increasing the separation distance, the mooring columnar body 12c is provided in connection with the end of the submerged buoyancy body 12b.

  When the wind power generator 10 is installed, the wind action point becomes higher from the water surface even during towing and installation, so it is easy to tip over, and there is a high risk of tipping over due to the inclination. The effect is important.

  A tension mooring line (tendon) 13 for tension-tethering the tension mooring floating body 1 to the anchoring bottom member 14 is formed of a steel chain, a cable, a rope, or the like, and the upper end of the tension mooring line 13 is a columnar body for mooring. A lower end portion of the upper anchoring portion 15c of 12c is attached to the lower anchoring portion 14c of the anchoring bottom member 14. At the time of mooring, the length of the tension mooring line 13 is adjusted so that tension is always applied to the tension mooring line 13 so that the floating body 12 is pulled into the water against the buoyancy of the floating body 12. Configure.

  The fixing bottom member 14 is a weight made of steel or concrete, also called a template, and is used as a gravity anchor that is submerged in the water bottom 2 and fixed by its own weight. In addition, you may use the piling (pile) fixed to the ground of the water bottom 2 as a fixed bottom member. The anchoring bottom member 14 is for mooring the floating body 12 at a preset position via the lower mooring portion 14c, the tension mooring line 13 and the upper mooring portion 15c. The part is fixed to the lower mooring part 14c.

The size of the tension mooring floating body 1 is, for example, when the power generation amount is assumed to be 2 MW, and the windmill 10a has a rotating diameter of about 80 m when installed at a water depth of about 100 m to 200 m on the continental shelf. The rotating shaft 10b of the wind turbine 10a is about 75m above the water surface 3, the diameter of the central columnar body 12a of the floating body 12 is about 6m and the height is about 35m, and the diameter of the mooring columnar body 12c is about 4m. The diameter of a circle passing through the centers of the three fixing bottom members 14 is about 60 m.

  Next, the support floating body 20 for the tension mooring floating body according to the embodiment of the present invention will be described. As shown in FIG. 3, the support floating body 20 is formed with a recess 21a into which the mooring columnar body 12c of the tension mooring floating body 1 enters, and is arranged along each of the mooring columnar bodies 12c. And a coupling member 22 for coupling the working floating body 21 to each other. For example, when the horizontal cross section of each mooring columnar body 12c is close to a quadrangle, the concave portion 21a is formed by a U-shaped notch surrounding it. Moreover, the coupling member 22 is formed with a detachable pipe structure (the cross section is not limited to a circle), for example, as shown in FIG.

  At the time of work support, the connection flange 21c (blind flange) of the connection cylindrical body 21b of the work floating body 21 disposed along each mooring columnar body 12c and the connection flange 22a (blind flange) of the coupling member 22 are provided. The support floating body 20 is formed by being integrated. Further, after the work support is completed, the connection flanges 21c and 22a are disconnected from each other and the connecting member 22 is separated from the work floating body 21, whereby each work floating body 21 is individually separated from the tension mooring floating body 12c. To be separated.

  With this configuration, since the work floating body 21 has the recess 21a into which the mooring columnar body 12c enters, the work floating body 21 increases along the mooring columnar body 12c (three sides in FIG. 3). It becomes difficult for the floating body 21 to be detached from the mooring columnar body 12c. This facilitates the joining operation with the coupling member 22. At the same time, the concave portion 21a abuts the mooring columnar body 12c so that it can move up and down. The inclination of the tension mooring floating body 1 is suppressed.

  In addition, the support floating body 21 is integrally formed by connecting the work floating body 21 with a detachable connecting member 22, thereby facilitating attachment to the tension mooring floating body 1. Thereby, the support floating body 20 can be arranged with a small work amount.

  Also, as shown in FIGS. 3 to 9, when the recess 21a is surrounded from the outside of the mooring columnar body 12c, the integrated work is performed more than when the recess 21a is surrounded from the inner side of the mooring columnar body 12c. Workability is improved. On the other hand, when the recess 21a is formed so as to surround the mooring columnar body 12c from the inside, the area occupied by the support floating body 20 in the horizontal plane can be made smaller than when the recess 21a is surrounded from the outside. It will be possible to work in a narrow place. In addition, it becomes possible to tow a narrow channel.

  Further, the concave portion 21a is brought into contact with a guide portion or the like of the mooring columnar body 12c via a rotating body 21d as shown in FIG. 5 so that the concave portion 21a can move relatively up and down relative to the mooring columnar body 12c. Arranged in contact. This rotating body 21d is divided into upper and lower parts and provided at several places. As this rotating body 21d, for example, an elastic roller provided rotatably can be used.

  The working floating body 21 of the supporting floating body 20 is configured to float on the water surface 3 so as to have a restoring force in a direction to prevent the inclination, and is provided over the vicinity of the water surface penetrating portion of the mooring columnar body 12c. . As a result, the work floating body 21 has a portion on the water surface on the water surface 3, so that the work for placement on the mooring columnar body 12 c and the connection work with the coupling member 22 are facilitated.

  Since the support floating body 20 is arranged along the mooring columnar body 12c in a state in which it can move up and down relatively with the mooring columnar body 12c, that is, in a slidable state, the mooring columnar body 12c. The buoyancy is not affected, but the inclination of the anchoring columnar body 12c is suppressed and the anchoring columnar body 12c is inclined. Thereby, the restoring force of the tension mooring floating body 1 is reinforced.

  The support floating body 20 is not fixed to the tension mooring floating body 1 but is slid along the mooring columnar body 12c so as to be always floated near the water surface 3 so that the support floating body 20 is disassembled and removed. A portion requiring work can always be maintained near the water surface 3. Therefore, after installation of the tension mooring floating body 1, that is, when removing the support floating body 20 after the tension mooring, it is possible to eliminate underwater work for removal at a deep water depth that makes the work difficult.

  Thereby, the inclination of the mooring columnar body 12c can be suppressed, the restoring force of the tension mooring floating body 1 can be reinforced, and the posture of the tension mooring floating body 1 can be stabilized. In other words, by arranging the support floating body 20, the heel (lateral inclination) and trim (vertical inclination) of the tension mooring floating body 1 can be suppressed. In particular, when the tension mooring floating body 1 is formed with a semi-submersible type floating body structure as shown in FIGS. 1 to 9, the intermediate stage of deepening the draft when shifting from the floating state to the semi-submersible state at the time of installation The support floating body 20 can reinforce the restoring force of the tension mooring floating body 1 significantly, so that the posture of the tension mooring floating body 1 at each stage when the draft is increased. Can be stabilized, and fall can be prevented. As a result, in the towing work and installation work of the tension mooring floating body 1, the towing and installation work of the tension mooring floating body 1 can be sufficiently supported, and the support by the large offshore crane can be made unnecessary.

  Further, for the tension mooring floating body 1, the support floating body 20 is provided with a work support system. This work support system includes a winding system of a tension mooring line 13 for tensioning the tension mooring floating body 1, a temporary mooring system for temporarily mooring the support floating body 20 along the tension mooring floating body 1, and a support It is configured by at least one of a ballast adjustment system for the floating body 20 itself, a power supply system for a tension mooring floating body, a power supply system for a support floating body, or some combination.

  As shown in FIG. 5, the winding system includes a winding drum 23a for winding the tension mooring line 13 and a pulley 23b for changing the direction of the tension mooring line 13, and the tension mooring line 13 is wound on the winding drum. Towed in a state of being wound around 23a, and in the installation water area, the tension mooring line 13 is unwound from the winding drum 23a via the pulley 23b, and the upper end of the tension mooring line 13 is fixed to the upper mooring part 15c. Drain and moor tension. In order to assist the removal of the pulley 23b after the tension mooring, it is convenient to mount a lifting device such as a small crane (not shown) on the support floating body 20.

  Further, the temporary mooring system includes a temporary mooring winch 24a and a temporary mooring cable 24b as shown in FIG. 5, and temporarily moors the tension mooring floating body 1 before tension mooring in the installation water area. . This temporary mooring system is configured such that it can be lowered while being suspended to the seabed 2 while supporting the weight of the fixing bottom member 14 installed on the seabed 2.

  Further, the ballast adjusting system includes a ballast pump 25a, ballast tanks 25b and 25c, a sea chest 25d serving as a seawater intake port, piping and a control valve for connecting them, as shown in FIG. When it is necessary to deepen the draft of the support floating body 20, seawater as ballast water is introduced from the sea chest 25 d by the ballast pump 25 a and injected into the ballast tanks 25 b and 25 c. When the draft of the support floating body 20 needs to be shallow, the ballast water is discharged from the ballast tanks 25b and 25c using the ballast pump 25a. By adjusting the ballast amount of these ballast tanks 25b and 25c, the subsidence amount and posture of the support floating body 20 itself are controlled.

  As the power supply system, there are a tension mooring floating body and a supporting floating body. For example, as shown in FIG. 6, the power supply system includes a fuel tank 26 a, a power generation engine 26 b, a power generation device 26 c, a switchboard 26 d, a control device, a charging device, and the like, and supplies power to the tension mooring floating body 1. Or a power supply for supplying power to each device of the support floating body 20 itself.

  For example, as shown in FIG. 6, the ballast adjustment system for the tension mooring floating body 1 includes a ballast pump 12ca, a ballast tank 12ba, a sea chest 12cb, and a pipe provided on the submerged buoyant body 12b. It has a control valve and the like. When it is necessary to deepen the draft of the tension mooring floating body 1, seawater as ballast water is introduced from the sea chest 12cb and injected into the ballast tank 12ba by the ballast pump 12ca. Further, when it is necessary to make the draft of the tension mooring body 1 shallow, or when it is necessary to make the entire weight of the floating body smaller than the buoyancy in order to increase the tension of the tension mooring line 13, the ballast tank 12ba is used by using the ballast pump 12ca. To discharge ballast water. The posture of the tension mooring floating body 1 is adjusted by adjusting the ballast amount of each submerged buoyancy body 12b.

  By providing this work support system on the support floating body 20 side, sufficient support can be provided during towing work and installation work. Moreover, the space of the support floating body 20 can be functioned as a work table at the time of towing and installation work. Thereby, in the prior art, the work ship that has been supporting power supply etc. can be used only for towing for movement, so a work support system is not required on the work ship side, This will expand the range of work vessels that can be used.

  Moreover, since some or all of the incidental facilities are provided on the support floating body 20 side, some or all of the incidental facilities on the tension mooring floating body 1 side are omitted, and the cost of the entire system of the tension mooring floating body 1 is reduced. be able to. Further, when a large number of tension mooring floating bodies 1 are installed, the support floating body 20 can be repeatedly used to reduce the towing and installation cost per unit of the tension mooring floating bodies.

  Next, the towing method of the tension mooring floating body 1 using the support floating body 20 having the above-described configuration will be described. In this towing, as shown in FIG. 7, when the tension mooring floating body 1 is towed, the support floating body 20 is towed in a state of being arranged along the tension mooring floating body 1.

  In the construction in the dock before that, the tension mooring floating body 1 is assembled on the upper part of the fixing bottom member 14, and the lower ends of the temporary mooring line 24b and the tension mooring line 13 are attached. The support floating body 20 is disposed in the recessed portion 21a by separating the work floating bodies 21 individually separated from the tension mooring floating body 1 via a pedestal or the like on the upper portion of the fixing bottoming member 14 in the dock. After the mooring columnar body 12c is arranged so as to enter, the connecting flange 21c of the connecting cylindrical body 21b of the working floating body 21 and the connecting flange 22a of the connecting member 22 are connected by a bolt or the like, and the connecting member 22 is used for work. Join the floating body 21. Then, water is poured into the dock and the dock is taken out.

FIG. 7 shows a state when the tension mooring floating body 1 is pulled out from the building dock and towed, and the support floating body 20 is tensioned moored in a state where the ballast tank 12ba of the tension mooring floating body 1 is floated without loading ballast water. It is arranged along the floating body 1. At the same time, the fixed bottom member 14 is suspended by the tension mooring line 13 and the temporary mooring line 24 b below the support floating body 20. About half of the ballast water is injected into the fixed bottom member 14 so that the submerged buoyant body 12b of the tension mooring floating body 1 is on the water surface 3. In this state, the central columnar body 12a, the submerged buoyant body 12b, and the lower part of the mooring columnar body 12c penetrate the water surface 3 and generate a restoring force against the inclination, but the center of gravity of the tension mooring floating body 1 from the water surface 3 Therefore, the support floating body 20 generates a greater restoring force and prevents the fall. In this state, it will be towed to the installation water area by a working ship such as a tugboat.

  According to this method, when the tension mooring floating body 1 is towed, the support floating body 20 is towed in a state of being arranged along the tension mooring floating body 1, so that the inclination of the mooring columnar body 12 c is suppressed by the support floating body 20. It is possible to secure the restoring force and to stabilize the posture of the tension mooring floating body 1. Therefore, the towing work can be sufficiently supported, and the support by the large offshore crane can be eliminated.

  Next, the installation method of the tension mooring floating body 1 using the support floating body 20 having the above-described configuration will be described. In this installation work, after being submerged from the towing state of FIG. 7 to the semi-submersible state of FIG. 8, tension mooring is performed to obtain the installation state of FIG.

  FIG. 8 shows a state where the ballast water is submerged from the state of FIG. 7 to the draft at the time of tension mooring by further injecting the ballast water into the fixing bottom member 14 and injecting the ballast water into the ballast tank 12ba of the submerged buoyancy body 12b. In this state, a part of the upper part of the mooring columnar body 12c is on the water surface.

In this state, the height of the center of gravity of the tension mooring floating body 1 from the water surface 3 is lower than that in the state of FIG. 7, but the portions penetrating the water surface 3 are the center columnar body 12a and the mooring columnar body 12c. The upper part is smaller and the restoring force against the inclination is also smaller. Even in this state, it is easy to fall, so that a large restoring force is generated by the support floating body 20 from the floating state of FIG. 7 to the semi-submerged state of FIG.

  Thereafter, the ballast water in the ballast tank 12ba of the submerged buoyancy body 12b is drained, the entire weight of the floating body is reduced from the buoyancy, and a predetermined tension is generated on the tension mooring line 13. When a predetermined tension is generated and the tension mooring floating body 1 is tension moored, the support floating body 20 is separated from the tension mooring floating body 1.

  It is preferable that the separation of the support floating body 20 is performed in a state in which the connecting portion between the work floating body 21 and the coupling member 22 comes out on the water surface as much as possible and the separation work can be easily performed. The work float 21 and the coupling member 22 are separated, and then the work float 21 is moved by a work boat or the like to separate the work float 21 from the mooring columnar body 12c. Due to the tension mooring by the tension mooring line 13 and the separation of the support floating body 20, an installation state as shown in FIG. 9 is obtained.

  According to this installation method, when the tension mooring floating body 1 is installed, the installation work is performed in a state where the support floating body 20 is arranged along the tension mooring floating body 1, so that the tension mooring floating body 1 is inclined by the support floating body 20. It is possible to perform the installation work in a state where the restoring force is secured and the posture of the tension mooring floating body 1 is stabilized while suppressing the above. Therefore, the posture of the tension mooring floating body 1 can be stabilized, and the support by the large offshore crane for preventing the fall can be made unnecessary.

  Further, according to this installation method, the anchoring bottom member 14 is lowered while supporting the weight by the temporary mooring system provided on the support floating body 20 side, so that it is fixed to the tension mooring floating body 1 side or the work ship side. Equipment such as a winch for lowering the bottom sink member 14 to the bottom of the water becomes unnecessary.

  Therefore, according to the support floating body 20 for the tension mooring floating body 1 and the towing method and installation method of the tension mooring floating body 1 using the support floating body 20, the towing operation towing the tension mooring floating body 1 to the installation water area Can increase the restoring force to further stabilize the posture of the tension mooring floating body 1, and in the installation of the tension mooring floating body 1 on the ocean, when the transition from the floating state before the tension mooring to the semi-submersible state Applying sufficient restoring force to the support floating body 20 to prevent the tension mooring floating body 1 from overturning or fixing the tension mooring line 13 of the tension mooring floating body 1 to the water bottom 2 of the fixing bottom member 14 In the installation work such as the sinking work and the tension adjustment of the tension mooring line 13, the power system is operated to operate the temporary mooring winch 24a and the ballast pumps 12ca and 25a for posture adjustment. As a result, the tow of the tension mooring floating body 1 is towed by the support floating body 20 that is temporarily arranged at the time of towing or installation work at the time of towing or installation of the tension mooring floating body 1. And can support the installation work.

  In addition, since the support floating body 20 is removed from the tension mooring floating body 1 except during towing and installation, the support floating body 20 can be repeatedly used when many tension mooring floating bodies 1 are installed. As a result, the cost of towing and installation per unit of the tension mooring floating body 1 can be reduced.

It is a figure which shows the structure of the tension mooring floating body in embodiment which concerns on this invention. It is a figure which shows the columnar body for mooring which has a water surface penetration buoyancy part in embodiment which concerns on this invention. It is a top view which shows the structure of the support floating body in embodiment which concerns on this invention. It is a perspective view which shows the coupling member of the support floating body. It is a fragmentary sectional view which shows the arrangement | positioning relationship between the work floating body of a support floating body, and the columnar body for mooring. It is a fragmentary sectional view which shows the installation of the work floating body and mooring columnar body of a support floating body. It is a side view which shows the towing state of the tension mooring floating body which has arrange | positioned the floating body for assistance. It is a side view which shows the semi-submerged state of the tension mooring floating body which has arrange | positioned the floating body for assistance. It is a side view which shows the tension moored state of the tension mooring floating body, and the separation state of the support floating body. It is a figure which shows the structure of the tension mooring floating body of a prior art. It is a figure which shows the state of the tension mooring floating body called mini TLP of a prior art.

Explanation of symbols

1, 1X, 1Y Tension mooring floating body 2 Water bottom 3 Water surface 10 Wind power generator 11 Upper structure 12 Floating body 12a Central columnar body (center column)
12b Submerged buoyant body (pontoon: connecting member)
12ba Ballast tank 12c Mooring pillar (corner column)
12ca ballast pump 12cb sea chest 13 tension mooring line (Tendon)
DESCRIPTION OF SYMBOLS 14 Fixed bottom member 14c Lower mooring part 15c Upper mooring part 20 Supporting floating body 21 Working floating body 21a Recessed part 21b Connection cylindrical body 22 Coupling member 23a Winding drum 23b Pulley 24a Temporary mooring winch 24b Temporary mooring cable 25a Ballast pump 25b, 25c Ballast tank 25d Sea chest 26a Fuel tank 26b Power generation engine 26c Power generation device 26d Switchboard

Claims (6)

A central columnar body penetrating the water surface, a mooring columnar body arranged around the central columnar body and to which an upper end side end of the tension mooring line is fixed, the central columnar body and the mooring columnar body, in order to assist the towing or installation work tension mooring floating having a coupling member for coupling to a support for a floating body which is arranged along said tension mooring floating at least one of during towing or when the installation work, the The support floating body is arranged along the mooring columnar body in such a state that the support floating body can move up and down relatively with the mooring columnar body without being fixed to the tension mooring floating body. Supporting floating body for tension mooring floating body.   Tension mooring line winding system for tension mooring floating body, temporary mooring system for temporarily mooring the support floating body in a state of being arranged along the tension mooring floating body, and the support floating body itself A work support system comprising at least one of a ballast adjustment system, a power supply system for the tension mooring floating body, a power supply system for the support floating body, or some combination thereof is provided. Item 4. A support floating body for a tension mooring floating body according to item 1.   The support floating body has a concave portion into which the mooring columnar body enters, and has a working floating body arranged along each of the mooring columnar bodies, and a coupling member that couples the working floating body. When the work support is configured, the work floating bodies arranged along the mooring columnar bodies are joined and integrated by the coupling member to form the support floating body. The support floating body for the tension mooring floating body according to claim 1, wherein a coupling member is separated from the working floating body, and the working floating body is separated from the tension mooring floating body. A central columnar body penetrating the water surface, a mooring columnar body arranged around the central columnar body and to which an upper end side end of the tension mooring line is fixed, the central columnar body and the mooring columnar body, When towing a tension mooring floating body having a connecting member for connecting the torsion tow, the support floating body for the tension mooring floating body according to claim 1, 2 or 3 is towed in a state of being arranged along the tension mooring floating body A towing method for a tension mooring float. A central columnar body penetrating the water surface, a mooring columnar body arranged around the central columnar body and to which an upper end side end of the tension mooring line is fixed, the central columnar body and the mooring columnar body, The installation method of the tension mooring floating body which uses the support floating body for the said tension mooring floating body of Claim 1, 2, or 3 in installation of the tension mooring floating body which has a connection member which connects.   The support floating body is formed with a temporary mooring system for temporarily mooring the tension mooring floating body, and when the tension mooring floating body is installed by the temporary mooring system, the temporary mooring is installed in the installation water area of the tension mooring floating body. The fixed anchoring member to which the lower end of the tension mooring line is moored by the system is sunk to the seabed, and the support floating body arranged along the tension mooring floating body is temporarily moored, and then the mooring by the tension mooring line is performed. 6. The installation method of a tension mooring floating body according to claim 5, wherein the temporary mooring is released after performing the mooring by the tension mooring line.

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