Lifting work boat and method for installing a cylindrical body using the same

Abstract

To provide an elevating-type working ship and an installing method of a cylindrical body using it capable of safely and efficiently installing the cylindrical body used for a monopile foundation and a support pile of a pile-supported structure.SOLUTION: The present elevating-type working ship 1 comprises buoyancy control means capable of sinking the working ship body 3 to a position where it is submerged in water, and a tilted frame 5 installed on a deck 3a of the working ship body 3, one end of which is located at a prescribed distance vertically from the deck 3a, and also which supports the cylindrical body 2 in a tilted state, The working ship submerges the working ship body 3 into the water while legs 4, 4..., are landed on the bottom of the water and can perform the erection work of cylindrical body in that state.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a lifting work vessel for installing cylindrical bodies used for the foundations of offshore wind power generation facilities, support piles of pile-supported structures, etc., and a method for installing cylindrical bodies using the same. [Background technology]

[0002] Fixed-bottom offshore wind power generation facilities are known to have wind turbines and other equipment supported by monopile foundations consisting of tubular bodies driven into the waterbed. Also, pile-supported structures such as piers are known to have superstructures supported by substructure foundations consisting of tubular bodies (steel pipe piles) driven into the waterbed.

[0003] A known method for installing this type of cylindrical body involves transporting a cylindrical body such as a monopile manufactured in a factory or manufacturing yard on land to a base port, loading it onto a lifting work vessel (hereinafter referred to as a SEP vessel) using a crane on the SEP vessel at the base port, and then transporting the cylindrical body by sea to the installation area and installing it on the SEP vessel.

[0004] Specifically, the cylindrical body is loaded onto an SEP vessel and transported by sea to the installation area, and then the legs of the SEP vessel are lowered and allowed to settle on the seabed at the installation area, and the main body of the SEP vessel supported by the legs is raised above the water, making the main body of the SEP vessel stable against waves and other disturbances.

[0005] Next, the cylindrical body such as a monopile loaded on the SEP vessel is lifted up and erected using the SEP vessel's crane, and then lowered in that state to the bottom of the water where it lands.

[0006] Then, the head of the cylindrical body that has been placed on the bottom of the water is driven in with a hammer or the like, so that the cylindrical body penetrates the bottom of the water and is installed. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-227966 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in recent years, as wind power generation equipment such as wind turbines and underwater and above-water structures such as piers have become larger and their installation locations have become deeper, the cylindrical bodies that make up the monopile foundations that support the wind turbines and the cylindrical bodies that support the superstructure have also become heavier and longer.As a result, the crane of the procured SEP ship did not have enough lifting capacity, and it was sometimes difficult to load the cylindrical bodies onto the hull and erect the loaded cylindrical bodies.

[0009] In that case, it would be necessary to separately arrange for a large crane vessel with a crane with a greater lifting capacity than the SEP vessel's crane, which would increase costs, complicate the adjustment of the work process, and make the work larger in scale.

[0010] Furthermore, as the waters where the installation is taking place become deeper, the SEP vessels used to install the cylindrical bodies also need to have longer legs, which poses the problem of the SEP vessels becoming larger and needing greater jacking capacity.

[0011] Furthermore, with conventional SEP vessels, work is carried out with the work vessel itself raised above the water while supported by the legs. During work, the legs are subjected to drifting forces (external forces) caused by waves and currents, so the legs must be strong enough to withstand this.

[0012] As a result, the construction costs of SEP vessels are quite high, which is a factor in increasing the construction costs of above- and underwater structures such as offshore wind power generation facilities and piers.

[0013] In view of the above-mentioned conventional problems, the present invention has been made with the aim of providing a lifting work vessel that can safely and efficiently install cylindrical bodies used for monopile foundations and support piles of pile-supported structures, and a method for installing cylindrical bodies using the same. [Means for solving the problem]

[0014] The feature of the invention described in claim 1, which solves the above-mentioned conventional problems, is that in an elevating work boat comprising a work boat main body capable of moving on the water and a plurality of legs supported on the work boat main body so that they can be raised and lowered, the legs being able to land on the bottom of the water and the work boat main body being supported on the legs, the invention comprises a buoyancy adjustment means capable of lowering the work boat main body to a position where it is submerged in the water, and a tilting platform installed on the deck of the work boat main body and supporting a cylindrical body with one end tilted at a predetermined distance perpendicular to the deck, the work boat main body comprising a base fixed to the deck and a pivotable connecting member rotatably supported on the base, the lower end of the cylindrical body being connected to the pivotable connecting member.

[0015] The feature of the invention described in claim 2 is that, in addition to the configuration of claim 1, the work boat main body is equipped with one or more floating body sections with adjustable buoyancy that are erected on the deck.

[0016] The invention as set forth in claim 3 is characterized in that, in addition to the configuration of claim 2, a working crane is installed on the floating body portion.

[0017] The invention as set forth in claim 4 is characterized in that, in addition to the configuration of any one of claims 1 to 3, the work vessel main body is provided with a plurality of thrusters.

[0018] The invention described in claim 5 is characterized in that, in a method for installing a cylindrical body, an upper end of the cylindrical body loaded on a work boat is lifted by a crane, the cylindrical body is erected, and then the cylindrical body is installed in water, A liftable work boat comprising: a work boat body capable of moving on water; a plurality of legs supported on the work boat body so that they can be raised and lowered; a buoyancy adjustment means capable of lowering the work boat body to any position in the water; and a tilting platform installed on the deck of the work boat body, one end of which supports the cylindrical body in a state where it is tilted at a predetermined distance in a direction perpendicular to the deck, the work boat body comprising a base fixed to the deck and a pivoting connecting member pivotally supported on the base. As the work boat and connecting the lower end of the cylindrical body to the rotary connecting member. After the legs are lowered and allowed to land on the bottom of the water, the upper end of the cylindrical body is lowered along the legs to a position where it protrudes above the water surface and the work vessel body is submerged in the water, and then: The lifting work boat The cylindrical body loaded on top is lifted up by the crane to stand, and the rotary connecting member is released from the lower end of the cylindrical body. [Effects of the Invention]

[0019] By being equipped with the configuration described in claim 1, the elevating work vessel of the present invention can reduce the jack-up capacity and the external force acting on the legs, and can accommodate larger cylindrical bodies with a work vessel equivalent to an existing SEP vessel. Furthermore, since the lower end of the cylindrical body is rotatably supported during the erection work, the cylindrical body can be erected smoothly.

[0020] Furthermore, in the present invention, by providing the configuration described in claim 2, the work vessel body can be submerged to the desired position of the floating section (column), and the underwater load can be freely set, thereby allowing the leg load to be freely controlled.

[0021] Furthermore, in the present invention, by providing the configuration described in claim 3, the cylindrical body can be lifted by a crane even when the work vessel body is submerged to a desired position in the floating body section.

[0022] Furthermore, in the present invention, by providing the configuration described in claim 4, the work vessel body can move independently in the installation waters, and the position of the work vessel body can be fine-tuned to the installation position of the cylindrical body without relying on towing, etc.

[0023] Furthermore, in this invention, by providing the configuration described in claim 5, it is possible to reduce the jacking capacity and the external force acting on the legs, and it is possible to accommodate larger cylindrical bodies with a work vessel equivalent to an existing SEP vessel. Also, because the lower end of the cylindrical body is rotatably supported during the erection work, the cylindrical body can be easily detached from the holding member after being erected smoothly and safely. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a side view showing a lifting type work boat according to the present invention. FIG. [Figure 2] FIG. [Figure 3] 1A is an enlarged side view showing the lower end of the cylindrical body connected to the rotational connecting member of the same, and FIG. 1B is a rear view of the same. [Figure 4] 1 is a schematic side view showing a state of loading work of a cylindrical body in a method of installing a cylindrical body using a lifting type work boat according to the present invention. FIG. [Figure 5] FIG. 10 is a schematic side view showing the state in which the cylindrical body is supported on the tilting stand. [Figure 6] FIG. 2 is a schematic side view showing the state in which a cylindrical body is being transported by the lifting type work boat. [Figure 7] FIG. 2 is a schematic side view showing the state in which the legs of the liftable work vessel have been placed on the bottom. [Figure 8] FIG. 2 is a schematic side view showing the state in which the main body of the liftable work boat is submerged in water. [Figure 9] FIG. 10 is a schematic side view showing the state during the erection operation of the cylindrical body. [Figure 10] FIG. 2 is a schematic side view showing the state in which the cylindrical body is placed on the bottom of the water. [Figure 11] FIG. 2 is a schematic side view showing the state when the cylindrical body is cast into the waterbed ground. DETAILED DESCRIPTION OF THE INVENTION

[0025] Next, an embodiment of the lifting work boat according to the present invention will be described based on the examples shown in Figures 1 to 3. In the figures, reference numeral 1 denotes the lifting work boat, and reference numeral 2 denotes a cylindrical body made of a steel pipe or the like.

[0026] As shown in Figures 1 and 2, the liftable work boat 1 comprises a work boat main body 3 having a deck 3a on the upper surface, a plurality of legs 4, 4... supported on the work boat main body 3 so that they can be raised and lowered, an inclined platform 5 installed on the deck 3a of the work boat main body 3, a plurality of tower-shaped columns 6, 6... installed on the deck 3a of the work boat main body 3, a buoyancy adjustment means that can lower the work boat main body 3 to a position where it is submerged in water, and a crane 7 installed on the top of the column 6, and is a semi-submersible work boat (semi-sub rig structure) that can lower the work boat main body 3 to the desired water depth with the legs 4, 4... touching the bottom of the water.

[0027] The work boat main body 3 is formed in a rectangular shape in a plan view, and is provided with thrusters 8, 8 . . . on the bottom of the boat, so that it can move on and underwater by the propulsive force of the thrusters 8, 8 .

[0028] Although not specifically shown, the work vessel main body 3 is equipped with a hollow ballast injection / discharge section inside, which allows the buoyancy to be adjusted by injecting or discharging ballast water, and functions as a buoyancy adjustment means that can lower the work vessel main body 3 to a position where it is submerged in water.

[0029] Each of the columns 6, 6... erected on the work vessel body 3 is formed in a hollow tower shape, and ballast water can be poured into and discharged from the inside, forming a floating body section with adjustable buoyancy.

[0030] Each of these columns 6, 6... is narrower in width in the hull width direction than the width of the work boat main body 3, and is configured so that when the work boat main body 3 is submerged, the waterline area is small and the projected area below the water surface is also relatively small.

[0031] The columns 6, 6, . . . that make up this floating body can be lowered to a common depth by adjusting the buoyancy, and the upper part can be kept floating above the water by the buoyancy.

[0032] The crane 7 comprises a rotatable rotating section 7a and a pair of jibs 7b, 7b supported by the rotating section 7a, and the rotating section 7a is rotatably installed on the upper surface of the columns 6, 6... that make up the floating section, so that it can always operate on water.

[0033] The work boat main body 3 also comprises a base 9 fixed to the deck 3a and a rotary connecting member 10 rotatably supported on the base 9, and the lower end of the cylindrical body 2 is connected to the rotary connecting member 10 so that part of the load of the cylindrical body 2 is loaded onto the rotary connecting member 10, and the upper end side is supported on the inclined frame 5 in a rotatable state via the rotary connecting member 10.

[0034] The base 9 is composed of a pair of bearing members 9a, 9a facing each other with a gap in the ship's width direction, and a rotary connecting member 10 is journaled between the bearing members 9a, 9a via a rotary shaft 11.

[0035] As shown in Figure 3, the rotating connecting member 10 comprises a plate-shaped rotating plate portion 10a that is pivotally supported on the base 9 via a rotating shaft 11, and a cylindrical fitting portion 10b whose lower end is supported on one end of the rotating plate portion 10a, and the lower end of the cylindrical body 2 is fitted into the upper end opening of the fitting portion 10b so as to abut against the rotating plate portion 10a.

[0036] The fitting portion 10b is open at both ends, and a rotating plate portion 10a is arranged to run vertically through the lower end opening, and open portions 10c, 10c are formed on both sides of the rotating plate portion 10a at the lower end opening, which communicate with the inside of the fitted cylindrical body 2.

[0037] The inclined platform 5 is composed of a plurality of support pillars 5a, 5a... erected on both sides of the loading position of the cylindrical body 2, and an arc-shaped receiving base 5b supported on the support pillars 5a, 5a... at a predetermined angle.By supporting the body of the cylindrical body 2 on the receiving base 5b, one end of the cylindrical body 2 is supported at an inclination at a predetermined distance vertically to the deck 3a.

[0038] Furthermore, the inclination angle of the inclined platform 5 is, based on the dimensions of the cylindrical body 2, an angle that prevents the tip of the cylindrical body 2 from becoming submerged when the hull is lowered; more specifically, an angle that makes it easy to raise the cylindrical body 2 when it is raised while the hull is lowered, and that allows safe rigging work to be performed at the tip of the cylindrical body 2. Furthermore, if the inclination angle is too large, the body will become unstable during transportation and the rigging work will be performed at a higher position, which is dangerous, so an angle of approximately 10 to 20 degrees is preferable, but other angles are also acceptable as long as they meet the above conditions.

[0039] Next, a method for installing the cylindrical body 2 using the above-described lifting work boat 1 will be described based on the embodiment shown in FIGS.

[0040] To install this cylindrical body 2, first, the cylindrical body 2 is manufactured in a factory, dry dock, etc., and then the cylindrical body 2 is loaded onto a transport barge (not shown), transported to the water area 13 in the harbor where the lifting work boat 1 is moored, and docked alongside the lifting work boat 1.

[0041] On the other hand, in the lifting work boat 1, the rotating connecting members 10 are rotated so that the upper opening side faces upward, and on the transport barge moored alongside, the lifting wires 12, 12 are slinged to the upper end of the cylindrical body 2 and the lower end side of the trunk of the cylindrical body 2. It is also possible to provide pieces for connecting the lifting wires at the slinging positions of the cylindrical body 2.

[0042] Next, as shown in FIG. 4, the barrel of the cylindrical body 2 is supported by the crane 7 of the liftable work vessel 1, and the upper end side is lifted up to make the cylindrical body 2 stand upright.

[0043] Then, the cylindrical body 2 in the upright state is moved onto the rotary connecting member 10, and at that position the cylindrical body 2 is lowered so that the lower end of the cylindrical body 2 is connected to the rotary connecting member 10 and loaded.

[0044] From this state, as shown in Figure 5, the hanging wires 12, 12 are unwound to rotate the cylindrical body 2, whose lower end is supported by the rotating connecting member 10, toward the deck 3a, and the upper end of the cylindrical body 2 is placed on the support base 5b and supported by the inclined frame 5.

[0045] This series of loading operations is repeated for each cylindrical body 2, and all of the cylindrical bodies 2 are loaded onto the work boat main body 3 with one end inclined at a predetermined distance in the vertical direction from the deck 3a, and then, as shown in Figure 6, the lifting work boat 1 carrying the cylindrical bodies 2 is towed to the installation water area 14 for the cylindrical bodies 2. Note that the cylindrical bodies 2 are stably supported by the rotating connecting member 10 and the tilting platform 5 when towing, but they may be secured just to be safe.

[0046] Next, as shown in FIG. 7, the position of the liftable work vessel 1 is finely adjusted in the installation waters 14, and the legs 4, 4 . . . are lowered to land on the water bottom 15.

[0047] Then, as shown in Figure 8, ballast water is injected into the work vessel main body 3 and the columns 6, 6... (floating body section) to adjust the buoyancy, and the work vessel main body 3 is lowered along the legs 4, 4... to a predetermined depth in the water, specifically, to a depth where the upper ends of the cylindrical body 2 and the columns 6 are not submerged.

[0048] At this time, buoyancy acts on the weight of the work vessel main body 3, and by adjusting this buoyancy, the underwater load can be freely set, thereby freely controlling the load acting on the legs 4, 4 . . .

[0049] In addition, the external forces acting on the lifting work boat 1 due to waves, etc. are determined mainly by the shape and area of ​​the waterline of the hull, and the external forces acting on the lifting barge due to tidal currents are determined by the projected area below the water surface.

[0050] In contrast, the liftable work boat 1 has the work boat main body 3 and the lower half of the columns 6, 6... (floating body section) submerged underwater, so the waterline area is small and the projected area below the water surface is also relatively small, which reduces the drifting force acting on the legs 4, 4...

[0051] On the other hand, when the liftable work boat 1 is submerged, the lower end of the cylindrical body 2 is submerged, but as the liftable work boat 1 is submerged, water also enters the inside of the cylindrical body 2 through the openings 10c, 10c of the rotating connecting member 10, so that no buoyancy is generated in the cylindrical body 2, and the lower end is connected to the rotating connecting member 10 and the upper end is maintained in a state where it protrudes diagonally above the water.

[0052] Next, as shown in Figure 9, a hanging wire 12 is connected to the upper end of the cylindrical body 2, and with the lower end supported by the rotary connecting member 10, the upper end side of the cylindrical body 2 is raised using a crane 7, and the cylindrical body 2 is erected with the cylindrical axis facing vertically (erasement work).

[0053] At this time, the upper end of the cylindrical body 2 protrudes above the water surface, so that rigging work can be carried out conveniently on the water, and the lifting wires 12, 12 can be safely and efficiently connected to the upper end of the cylindrical body 2.

[0054] Furthermore, since the cylindrical body 2 is supported on the inclined platform 5 at the time the erection work begins, the upper end side is inclined at a certain angle relative to the deck 3a, and the rotating connecting member 10 supporting the lower end of the cylindrical body 2 rotates in conjunction with the erection of the cylindrical body 2 by the suspension wire 12, so the cylindrical body 2 can be easily erected.

[0055] Then, once the cylindrical body 2 is erected in the vertical direction, the cylindrical body 2 is lifted vertically upward from that state by the crane 7, and the lower end of the cylindrical body 2 is released from the rotary connecting member 10 (connecting member releasing work).

[0056] Next, the lifted cylindrical body 2 is moved to the installation position by the crane 7, and then, as shown in Figure 10, the lifting wires 12, 12 are let out to allow the lower end of the cylindrical body 2 to land on the water bottom 15, and the cylindrical body 2 is grasped by the pile gripper 16 to stabilize it (bottom landing work).

[0057] Then, as shown in Figure 11, the upper end of the cylindrical body 2 is driven in with a hammer 17 or the like, and the lower end of the cylindrical body 2 is driven into the water bottom 15 (driving work). Note that reference numeral 18 in the figure denotes a receiving member attached to the upper end of the cylindrical body, and the cylindrical body 2 is driven in with the hammer 17 via this receiving member 18. Note that when a vibro hammer is used as the hammer 17, the receiving member 18 does not have to be provided.

[0058] Furthermore, this erection work, connecting member release work, bottom landing work and concrete pouring work are repeated for each cylindrical body 2, and the installation work of the cylindrical body 2 is completed.

[0059] The liftable work boat 11 then discharges ballast water from the work boat main body 32 and the columns 6, 6... (floating body sections) 3, 3... to float the work boat main body 32, and while the work boat main body 3 is floated, it pulls up the legs 4, 4... and then returns to port.

[0060] In the thus configured liftable work boat 1 and the method of installing the cylindrical body 2 using it, by submerging the work boat main body 3, buoyancy acts on the weight of the work boat main body 3 and columns 6, 6..., and by adjusting the buoyancy, the underwater load can be freely set, so that the load acting on the legs 4, 4... that support the work boat main body 3 can be freely controlled.

[0061] Therefore, with this lifting work vessel 1, the external forces acting on the legs 4, 4... can be reduced, and the jacking capacity can be reduced. Furthermore, a work vessel equivalent to an existing SEP vessel can accommodate a larger cylindrical body 2, thereby reducing construction costs. [Explanation of symbols]

[0062] 1. Lifting work boat 2 Cylindrical body 3. Workboat body 4th Leg 5 Inclined stand 6. Column 7 Crane 8 thrusters 9 Foundation 10 Rotating connecting member 11 Rotating shaft 12 Lifting wire 13 Port waters 14 Installation water area 15 Pile Gripper 16 Hammer 17 Receiving member

Claims

1. A lifting type work vessel is provided with a work vessel body that can move on water, and a plurality of legs that are supported on the work vessel body so that they can be raised and lowered, and the legs are set on the bottom of the water, and the work vessel body is supported on the legs. a buoyancy adjustment means for lowering the work vessel body to a position where it is submerged in water; and a tilting platform that is installed on the deck of the work vessel body and supports a cylindrical body with one end tilted at a predetermined distance in a direction perpendicular to the deck, The work boat main body comprises a base fixed to the deck and a pivotable connecting member rotatably supported on the base, and the lower end of the cylindrical body is connected to the pivotable connecting member.

2. 2. The elevating work boat according to claim 1, wherein the work boat main body is provided with one or more floating body sections with adjustable buoyancy erected on the deck.

3. 3. The elevating work vessel according to claim 2, wherein a work crane is installed on the floating body portion.

4. 4. The elevating work boat according to claim 1, wherein the work boat main body is provided with a plurality of thrusters.

5. A method for installing a cylindrical body, comprising: lifting an upper end of a cylindrical body loaded on a work vessel with a crane; erecting the cylindrical body; and installing the cylindrical body in water, the method comprising the steps of: a work boat body capable of moving on the water, a plurality of legs supported on the work boat body so as to be able to rise and fall, a buoyancy adjustment means capable of lowering the work boat body to any position in the water, and a tilting platform installed on the deck of the work boat body and supporting the cylindrical body with one end tilted at a predetermined distance in a direction perpendicular to the deck, the work boat body comprising a base fixed to the deck and a pivoting connecting member pivotally supported on the base, The lower end of the cylindrical body is connected to the rotation connecting member, After the legs are lowered and landed on the bottom of the water, the upper end of the cylindrical body is protruded above the water surface along the legs, and the work vessel main body is lowered to a position where it is submerged in water; Thereafter, the cylindrical body loaded on the lifting work vessel is lifted up and erected by the crane, and the rotating connecting member is released from the lower end of the cylindrical body.

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