JP5820678B2 - Offshore structure and its installation structure - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an offshore structure that is erected with support on the ground of the seabed, for example, an offshore structure that is installed in a sea area as a support frame for an offshore wind power generator, and an installation structure and an installation method thereof. It is.

  As this type of marine structure, a monopole type or a saddle type jacket type is known. The monopole type resists horizontal forces and moments due to the horizontal reaction force of the ground and the bending strength of the steel pipe, so the steel pipe must be made large-diameter and thick, and the processing of large-diameter steel pipe increases in weight. This requires a large-scale facility and requires labor and time, and requires large-scale equipment and labor and time to penetrate large-diameter steel pipes into the seabed, resulting in high costs. In addition, it is difficult to adjust the natural period, the attenuation rate is low, and there is a problem that the support performance of the apparatus with a large vibration such as an offshore wind power generator is low in terms of weight.

  In addition, the conventional saddle-shaped jacket type is difficult to adjust the natural period despite its complex shape, has a low damping rate, and is used as a support frame for devices with large vibrations such as offshore wind power generators. There is a problem that the supporting performance is low.

  Therefore, in Patent Document 1 below, a central shaft made of a large-diameter steel pipe is erected as a central support column, and a plurality of linear legs are formed so as to surround the central shaft. Arranged along each oblique ridgeline of a virtual solid obtained by twisting the base around its central axis, and connecting a support material extending in a branch shape obliquely upward and downward from the central shaft to each leg member Thus, an offshore structure that supports each leg member is disclosed.

  According to this offshore structure, since the legs are in a twisted relationship with each other, the natural frequency can be easily adjusted and the damping rate can be increased, resulting in large vibrations like offshore wind power generators. Support performance as a support frame of the apparatus can be enhanced.

International Publication No. 2010/144570

  However, the offshore structure described in Patent Document 1 has a central shaft standing at the center of a region surrounded by a plurality of legs, so that the amount of steel used and the weight of the steel increase, and the structure is There is a problem that it is complicated and requires labor and time for assembly and construction, resulting in high costs. In addition, since there is an obstacle called the central shaft in the area surrounded by the legs, there is a problem that it is easily affected by wave energy and tidal energy.

  In consideration of the above circumstances, the present invention can easily adjust the natural frequency and increase the damping rate, and can reduce the cost with a simple structure. Moreover, the effects of wave energy and tidal current energy can be achieved. It is intended to provide an offshore structure that can effectively reduce the load, and can exhibit effective support performance as a support frame for a device with large vibration, such as an offshore wind power generator, and its installation structure and installation method. .

In order to solve the above-mentioned problem, the offshore structure of the invention of claim 1 has a solid basic shape obtained by twisting a polygonal frustum whose lower part is widened and the upper part is narrowed around its central axis, By arranging straight legs along the oblique ridgelines of the solid, the center line of each leg or its extension line is in contact with a virtual cylinder centering on the central axis of the solid The legs are interconnected by a joining member in the vicinity of the contact point between the virtual cylinder and the center line of each leg, and are surrounded by the legs below the height level at which the joining member is disposed. A vertical plate along the vertical direction as the joining member, and joining the legs together by joining the vertical plates to the legs along the vertical direction. The vertical plate is cylindrical Alternatively, it is a conical cylinder-shaped vertical cylindrical plate, which includes upper and lower horizontal plates extending in the horizontal direction as the joining member, and an upper horizontal plate is joined to an upper part of the vertical plate, and a lower horizontal plate is joined to the vertical plate. By joining the lower part of the plate, passing the leg material through a plurality of through holes formed in the upper and lower horizontal plates, respectively, and joining the horizontal plate and the leg material along the horizontal direction at the penetration part The legs are interconnected .

A second aspect of the invention is the offshore structure according to the first aspect, wherein the joining member is a disc-shaped horizontal plate disposed on upper and lower ends of the vertical cylindrical plate. And

Invention of Claim 3 is an offshore structure of Claim 1 or 2, Comprising: The said joining member is comprised by the said vertical cylindrical plate and the said horizontal plate of the ring shape above and below, The upper side The horizontal plate is configured to have a larger diameter than the lower horizontal plate .

Invention of Claim 4 is the installation structure of the offshore structure as described in any one of Claims 1-3 , Comprising: The leg material of the offshore structure was inserted in the inside of this outer steel pipe and this outer steel pipe It is composed of an inner steel pipe pile, the marine structure is installed on the seabed, the lower end of the inner steel pipe pile is inserted into the ground of the seabed, and the outer steel pipe and the inner steel pipe pile are joined together in that state. Features.

Invention of Claim 5 is the installation structure of the offshore structure of Claim 4 , Comprising: The said inner steel pipe pile is comprised by the rotation penetration pile with the blade | wing at the lower end, and the said offshore structure is installed in the seabed Then, by rotating the rotary penetration pile, the lower end is penetrated into the ground of the seabed, and the outer steel pipe and the rotary penetration pile are integrally joined in this state.

Invention of Claim 6 is the installation structure of the offshore structure of Claim 5 , Comprising: It becomes possible to cancel | release the joining of the said outer steel pipe and the said rotation penetration pile, and the said rotation penetration by releasing joining. It is characterized in that the pile is configured to be rotatable in the direction opposite to that when penetrating.

The invention of claim 7 is a installation structure of marine structure according to any one of claims 4-6, the space inside space and the inside pipe pile between the outer steel pipe and the inner pipe pile By filling concrete into at least one of the spaces, the leg material has a steel pipe concrete structure.

Invention of Claim 8 is the installation structure of the offshore structure of Claim 7 , Comprising: On the contact surface of the said filled concrete and the said outer steel pipe or an inner steel pipe pile, it is a viscous body, a viscoelastic body, and plasticity. A material having a high attenuation rate such as a body or an elasto-plastic body is inserted.

The invention of the first reference example of the present invention is a method for installing an offshore structure having a plurality of legs, and the legs are constituted by an outer steel pipe and an inner steel pipe pile inserted into the outer steel pipe. In both cases, the inner steel pipe pile is composed of a rotary penetrating pile with a blade at the lower end, a rotary penetrating machine for rotating the rotary penetrating pile is mounted on the offshore structure, and the offshore structure is suspended by a crane. The bottom of the rotary penetrating pile is penetrated into the ground of the seabed by rotating the rotary penetrating pile with the rotary penetrating machine while maintaining the suspended and supported state. At the established stage, the suspension of the offshore structure by the crane is released, and the outer steel pipe and the rotary penetrating pile are integrally joined.

The invention of the second reference example of the present invention is an installation method of the offshore structure of the first reference example , wherein the rotation penetrating pile is penetrated into the ground of the seabed and / or after the penetration. Taking the support of the jack on the penetrating pile, making the pulling resistance and pushing resistance of the blades at the lower end of the rotating penetrating pile the reaction force, moving the outer steel pipe up and down using the jack, moving the marine structure up and down The level is adjusted in the direction.

  According to the offshore structure of claim 1, since the plurality of legs arranged so that each center line is in contact with the virtual cylinder does not have an intersecting point, sufficient work is performed between the legs and the legs. Space can be secured, and it is easy to make long joint piles by sequentially connecting the legs. Further, in this structure, the radius of the circle formed by the center point of each leg member on the plane orthogonal to the central axis of the solid body is minimum at the height at which the virtual cylinder and the center line of each leg member are in contact with each other. Work at the top of the structure by placing the top of the structure at a height level where the radius of the circle increases as it goes upward and downward, respectively, as it goes downward and upward from the contact Space can be secured easily. Moreover, since the space | interval of a leg spreads so that it goes to the lower part of a structure, it becomes easy to ensure the strut distance of the leg in the lower part of a structure.

  In addition, the angle of each leg can be set freely just by arranging each leg so that each center line is in contact with the virtual cylinder, so that the ideal distribution of axial force and bending force can be easily performed. Can be set. In addition, since the legs are located in a twisted relationship, it is possible to easily adjust the natural period of the structure using torsional deformation, and when mounting a vibrating machine such as a wind turbine for wind power generation In addition, vibration responsiveness can be reduced, vibration responsiveness to seismic motion can be reduced, and a damping rate against vibration can be increased. In addition, since the legs are interconnected by the joining members in the vicinity of the contact point between the virtual cylinder and the center line of each leg, that is, in the vicinity of the position where the distance between the legs is minimized, the size of the joining member is reduced. can do.

  In addition, the area surrounded by the legs below the height level where the joining members are arranged is secured as an open space, and the central shaft is not arranged in the center of the area surrounded by the legs as in the conventional example. Thus, since all the legs are joined together, the amount of steel used and the weight of the steel can be reduced as compared with the conventional example having a central shaft. In addition, since there is no central shaft in the center of the region surrounded by the legs, wave energy and tidal energy can be released in the open space, so that the influence of the energy can be reduced. In addition, since the structure is simplified to the extent that there is no central shaft in the region surrounded by the legs, construction is facilitated and costs can be reduced.

According to the offshore structure of claim 1, since the legs are interconnected by joining the vertical plates to the legs along the vertical direction, compared to the case where the legs are interconnected with a truss structure. The required strength can be easily obtained with a small amount of steel.

According to the offshore structure of the first aspect , since the legs are interconnected using the cylindrical or conical cylindrical vertical cylindrical plate, the rigidity of the structure in the axial direction can be enhanced.

According to the offshore structure of claim 1 , the leg material is respectively penetrated through the plurality of through holes formed in the upper and lower horizontal plates, and the horizontal plate and the leg material are joined along the horizontal direction at the penetration portion. Since the legs are interconnected, the required strength can be easily obtained with a small amount of steel material used compared to the case where the legs are interconnected with a truss structure. Further, the upper surface of the horizontal plate can be used as a work deck.

According to the installation structure of the offshore structure of claim 4 , the leg is composed of the outer steel pipe and the inner steel pipe pile, the offshore structure is installed on the seabed, and the lower end of the inner steel pipe pile is inserted into the ground of the seabed. In this state, since the outer steel pipe and the inner steel pipe pile are integrally joined, the offshore structure can be firmly supported by the ground of the seabed. In addition, it is easy to install because the inner steel pipe pile can be inserted using the outer steel pipe as a guide, just by inserting the lower end of the inner steel pipe pile inserted inside the outer steel pipe into the ground of the seabed. Can be.

According to the installation structure of the offshore structure of claim 5 , since the rotary intrusion pile with blades at the lower end is penetrated into the ground of the seabed as an inner steel pipe pile, the pulling resistance of the inner steel pipe pile is increased by the lower end blades. Can do. Therefore, even if the inner steel pipe piles are reduced in depth, sufficient resistance can be exerted when a horizontal load or moment is applied to the top of the offshore structure. In addition, the rotating penetrating pile can exert a large pulling resistance and pushing resistance by penetrating into the ground of the seabed, so by using a jack supported on the upper part of the rotating penetrating pile, Level adjustment in the vertical direction can be easily performed, and high-precision construction is possible.
In addition, since the rotary penetration pile with blades can be inserted into the outer steel pipe in advance, the rotary penetration pile that is the inner steel pipe pile can be penetrated into the ground of the seabed while using the outer steel pipe as a guide, It is possible to improve the efficiency and accuracy of on-site construction. In addition, since the rotary penetrating pile can be inserted into the ground by rotating it with a rotary penetrating machine, no noise or vibration occurs during construction, and environmentally friendly construction is possible. . Moreover, since the rotation penetration pile can be safely inserted into the ground while canceling the reaction force with the offshore structure suspended, construction management can be easily performed. Moreover, since the rotation penetration pile can be easily pulled out from the ground by rotating in the direction opposite to that at the time of construction, the removal of the offshore structure is easy and the removal cost can be reduced.

According to the installation structure of the offshore structure of claim 6 , the rotary penetrating pile is easily pulled out from the ground by releasing the joint between the rotating penetrating pile and the outer steel pipe and rotating the rotary penetrating pile in the direction opposite to that at the time of penetration. Can be easily removed.

According to the installation structure of the offshore structure of claim 7 , by using the steel pipe concrete structure as the leg material, the outer diameter of the outer steel pipe can be increased and the wall thickness can be reduced without increasing the weight. The buckling strength can be improved. Therefore, it is possible to realize a simple structure with a minimum of reinforcing materials such as horizontal materials, diagonal materials, bracing materials, and the like, and it is possible to reduce costs by using spiral steel pipes and ERW steel pipes.

According to the offshore structure installation structure of claim 8, a material having a high damping rate such as a viscous body, a viscoelastic body, a plastic body, or an elastic-plastic body is provided on the contact surface between the concrete and the outer steel pipe or the inner steel pipe pile. Since it is inserted, relative displacement between the outer steel pipe and the inner steel pipe pile and the concrete is possible, and the material such as the viscous body and the viscoelastic body undergoes shear deformation, thereby increasing the damping rate of the structure. . In addition, by inserting a material such as the viscous body or viscoelastic body between the concrete and the rotating penetrating pile, the concrete and the rotating penetrating pile can be unbonded. As a result, the rotating penetrating pile is rotated in the reverse direction. Can be easily pulled out, and the removal of the structure can be facilitated.

According to the offshore structure installation method of the first reference example , the rotating penetrating pile inserted into the outer steel pipe is rotated by the rotating penetrating machine, so that the rotating penetrating pile can be accurately suspended while the offshore structure is suspended by the crane. It can penetrate into the seabed. Then, after the penetration of the rotary penetrating pile, the outer steel pipe and the rotary penetrating pile are joined together so that the offshore structure can be installed on the ocean while securely supporting the ground on the seabed. Therefore, construction on the ocean can be simplified, and the cost can be reduced and the construction period can be shortened.

According to the offshore structure installation method of the second reference example , the jack is supported by the rotating penetrating pile that has penetrated into the ground of the seabed, and the level of the offshore structure is adjusted in the vertical direction using the jack. Stable construction is possible.

It is a perspective view which shows schematic structure of the offshore structure of 1st Embodiment of this invention. It is a perspective view which shows arrangement | positioning of the leg material of the marine structure. It is a perspective view which shows schematic structure of the offshore structure of 2nd Embodiment of this invention. It is explanatory drawing of the process in the case of constructing the marine structure of the said 1st Embodiment in a sea area. It is explanatory drawing of the next process of FIG. It is explanatory drawing of the next process of FIG. It is explanatory drawing of the next process of FIG. It is explanatory drawing of the next process of FIG. It is explanatory drawing of the next process of FIG. FIG. 10 is an explanatory diagram of the next process of FIG. 9. It is explanatory drawing of the next process of FIG. It is explanatory drawing of the next process of FIG. It is explanatory drawing of the next process of FIG. It is explanatory drawing of the next process of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a schematic configuration of the offshore structure of the first embodiment, and FIG. 2 is a perspective view showing an arrangement of legs of the offshore structure.

  A marine structure 1 according to the first embodiment shown in FIG. 1 is installed on the ground at the bottom of the sea as a support frame for an offshore wind power generator. As shown in FIG. A solid (not shown in particular) obtained by twisting a base (in this embodiment, a triangular frustum but a polygonal frustum greater than or equal to a square frustum) around its central axis L is a virtual basic shape. By arranging three straight legs 2 along the oblique ridgelines of the solid, the center line S of each leg 2 or its extension line is assumed to be a virtual centered on the central axis L of the solid. It is comprised so that the cylinder 10 may be contact | connected. Then, in the vicinity of the contact point 11 of the virtual cylinder 10 and the center line S of each leg 2, as shown in FIG. 1, the legs 2 are connected to each other by the upper joining member 20, and the upper joining member 20 is arranged. The area surrounded by the leg 2 below the height level is secured as an open space 5 where there is nothing like the central shaft of the conventional example. Further, the lower ends of the three leg members 2 having an interval are connected to each other by a triangular lower joint member 30.

  As shown in FIG. 1, as the upper joining member 20, a cylindrical vertical cylindrical plate 21 along the vertical direction is used in which a disk-shaped horizontal plate 22 is arranged on the upper and lower ends, and the vertical cylindrical shape is used. The plate 21 is joined to each leg member 2 along the vertical direction, and the horizontal plates 22 at the upper and lower ends are in a state where the leg member 2 is passed through a plurality of through holes 22a formed on the plate, respectively. Thus, the three legs 2 are connected to each other by joining the horizontal plate 22 and the legs 2 in a circumferential shape along the horizontal direction. The lower joining member 30 includes three plate-shaped beam members 31 that connect the lower end and the lower end of the leg member 2.

  According to the offshore structure 1 configured in this way, a plurality of (three in this embodiment) leg members 2 arranged so that each center line S is in contact with the virtual cylinder 10 have intersections that intersect each other. Therefore, it is possible to secure a sufficient working space between the leg 2 and the leg 2, and it is easy to make a long joint pile by sequentially connecting the legs (inner steel pipe piles 3) as described later. .

  Further, in this offshore structure 1, as shown in FIG. 2, the radius of the circle A formed by the center point a of each leg 2 on the plane orthogonal to the solid central axis L is the same as that of the virtual cylinder 10. Since the height of the contact point 11 with which the center line S of each leg 2 is in contact is minimized, the radius of the circle A increases as it goes upward from the contact point 11 as it goes downward and upward. By arranging the top of the offshore structure 1 at the height level, it is possible to easily secure a working space at the top of the offshore structure 1.

  Moreover, since the space | interval of the leg material 2 spreads, so that it goes to the lower part of the offshore structure 1, the securing distance of the leg material 2 in the lower part of the offshore structure 1 can be ensured now. Further, the angle of each leg member 2 can be set freely only by arranging each leg member 2 so that each center line S is in contact with the virtual cylinder 10, so that the axial force and the bending force are ideal. Distribution can be set easily.

  Further, since the leg 2 is located in a twisted relationship, the natural period of the offshore structure 1 can be easily adjusted using torsional deformation, and a vibrating machine such as a wind turbine for wind power generation can be used. Even in the case of mounting, vibration responsiveness can be reduced, vibration responsiveness to earthquake motion can be reduced, and a damping rate against vibration can be increased. Further, the leg member 2 is interconnected by the upper joining member 20 in the vicinity of the contact point 11 of the virtual cylinder 10 and the center line S of each leg member 2, that is, in the vicinity of the position where the distance between the leg members 2 is minimized. Therefore, the size of the upper bonding member 20 can be reduced.

  Moreover, the area | region enclosed by the leg material 2 below the height level which has arrange | positioned the upper joining member 20 is ensured as the open space 5, and a center shaft is set in the area | region enclosed by the leg material like the prior art example. Since all the leg members 2 are joined together without being arranged, the amount of steel material used and the weight of the steel material can be reduced as compared with the conventional example having a central shaft. Moreover, since there is no central shaft in the center of the area | region enclosed by the leg material 2, since wave energy and tidal current energy can be released in the open space 5, the influence by those energy can be reduced. In addition, since the structure is simplified to the extent that there is no central shaft in the region surrounded by the legs 2, the construction is facilitated and the cost can be reduced.

  Further, according to the offshore structure 1 of the present embodiment, the upper tubular member 21 is provided with the vertical cylindrical plate 21 and the horizontal plate 22, and the vertical cylindrical plate 21 is joined to each leg member 2 along the vertical direction. The leg 2 is passed through the plurality of through-holes 22a formed in the horizontal plate 22 and the horizontal plate 22 and the leg 2 are joined in the horizontal direction at the penetrating portion. Compared with the case where the materials 2 are interconnected, the required strength (particularly the axial stiffness) can be easily obtained with a small amount of steel material used. Further, the upper surface of the horizontal plate 22 can be used as a work deck.

FIG. 3 is a perspective view showing a schematic configuration of an offshore structure 1B according to the second embodiment of the present invention.
In the offshore structure 1B of the second embodiment, the leg 2 is disposed along each imaginary solid ridgeline in which the triangular frustum is twisted further than in the first embodiment, and the center of the leg 2 is arranged. A virtual cylinder (not shown in the figure) in contact with the line S is made larger in diameter than in the first embodiment, and the distance between the leg members 2 is kept wide, and the upper joint member 20B is formed in a conical cylindrical shape. The vertical cylindrical plate 21 </ b> B and the upper and lower ring-shaped horizontal plates 22, 23 are configured, and the upper horizontal plate 23 is configured to have a larger diameter than the lower horizontal plate 22. Other configurations are the same as those in the first embodiment. Was the cone-cylindrical vertical tubular plate 2 1 instead of the cylindrical vertical tubular plate 21, from the relationship leg members 2 are arranged the upper joint member 20B to gradually spread portion upward It is. The reason for increasing the diameter of the upper horizontal plate 23 is the same reason. Also in the offshore structure 1B of this embodiment, the same effect as that of the first embodiment can be obtained. Furthermore, since the space | interval of the leg material 2 was expanded, the effect that the work space can be secured more easily and the work deck can be made wider can be obtained.

  Next, referring to FIG. 4 to FIG. 14 for the installation method in the case where the offshore structure 1 having the above configuration (or the offshore structure 1B of the second embodiment) may be installed on the seabed and the installation structure obtained thereby. While explaining.

  When this offshore structure 1 is installed on the seabed, each leg member 2 is constituted by an outer steel pipe and an inner steel pipe pile inserted into the outer steel pipe. In the following drawings, the outer steel pipe is indicated by reference numeral 2 (for convenience, the same reference numerals as those of the legs in FIGS. 1 to 3), and the inner steel pipe pile (rotary penetrating pile) is indicated by reference numeral 3.

  As shown in FIG. 4, the offshore structure 1 of the first embodiment is assembled in advance in a factory or on a ship, and is laid on a carriage 100 and transported to an installation sea area. The inner steel pipe pile 3 is inserted into the inside of the leg member 2 of one embodiment. As the first inner steel pipe pile 3, a rotary penetrating pile 3 having a blade 3a at the lower end is used. Here, since the only difference is whether or not there is a blade at the lower end, both the rotary penetrating pile and the inner steel pipe pile added on the same are indicated by the same reference numeral 3.

  Next, with the rotary penetration pile 3 temporarily fixed to the outer steel pipe 2, the offshore structure 1 can be erected as shown in FIG. 5, and the rotary penetration pile 3 can be rotated at the upper end of the outer steel pipe 2. At the same time, as shown in FIG. 6, the next inner steel pipe pile 3 is welded to the upper end of the rotary penetrating pile (inner steel pipe pile) 3 and added. In such a work, since the legs 2 are arranged in a twisted relationship with each other, there is no intersection, so that it is possible to easily add the inner steel pipe pile 3 and to secure the work space easily. Can be.

Next, as shown in FIG. 7, the hose 132 of the hydraulic pump 130 is connected to each rotary penetration machine 120 to complete the preparation. The hydraulic pump 1 30 may be disposed on the trolley 100 as shown in FIG. 7, but may be disposed on the offshore structure 1 (portion that emerges on the sea surface when installed on the seabed). . Further, the number of inner steel pipe piles 3 to be added may be one, two or any number. When attaching them together, it is better to use a jig. Moreover, although the joint part of the inner steel pipe pile 3 may be welded on the trolley 100, it may be temporarily attached as will be described later, and may be welded at the time of installation.

Then, as shown in FIGS. 8 and 9, to implantation of the marine structure 1 to the seabed 200 Lower hanging on the sea from above Theissen 100 by the crane 1 1 0. At the time when the lower end of the outer steel pipe 2 reaches the seabed 200 or before and after it, the offshore structure 1 is positioned or the horizontal level is adjusted while being suspended. Then, it is suspended until the load is sufficiently transmitted to the seabed ground 201. At this stage, the blade 3a at the lower end of the rotary penetrating pile 3 is slightly penetrated into the ground 201 by its own weight.

  Next, the rotary penetrating machine 120 is remotely controlled from the top of the carriage 100, and the rotary penetrating pile 3 is penetrated into the ground 201 until the risk of collapse of the offshore structure 1 disappears as shown in FIG. When the stability is secured, the worker moves on the offshore structure 1 at that stage, removes the wire of the crane 110, and as shown in FIG. The first vertical level adjustment of the offshore structure 1 is performed with the vertical pressure jack, and the rotary penetration pile 3 is further rotated to penetrate. At this time, not only the level adjustment but also the adjustment of the level of the upper joint member 20 is performed at the same time by individually adjusting the lengths of the legs 2 as necessary. This level adjustment and rotation penetration were repeated several times, and as shown in FIG. 12, it was confirmed by torque that the lower end of the rotation penetration pile 3 reached the support layer 210, and necessary torque or necessary penetration amount was secured. Stop at the top.

  In this case, the level adjustment in the vertical direction of the offshore structure 1 during and / or after the penetration of the rotary penetrating pile 3 into the ground 201 of the seabed is carried out by supporting the rotary penetrating pile 3 with a jack. The pulling resistance and pushing resistance of the blade 3a at the lower end of the pile 3 are set as reaction forces, and the outer steel pipe 2 is moved up and down using a jack. As described above, the level of the offshore structure 1 is adjusted repeatedly in the vertical direction, so that accurate and stable construction can be performed.

  Then, as shown in FIG. 13, the rotary penetration machine 120 is removed, and the inner steel pipe pile 3 and the outer steel pipe 2 are joined. In addition, the removal work of the offshore structure 1 can be easily performed now that this joining can be released later. Further, in the next step, concrete (including a grout material in addition to concrete in a narrow sense) 6 is placed as shown in FIG. At this time, the concrete 6 is cast and filled in at least one of the space between the outer steel pipe 2 and the inner steel pipe pile 3 and the inner space of the inner steel pipe pile 3. By doing so, the leg material (outer steel pipe 2 or / and inner steel pipe pile 3) of the marine structure 1 can be made into a steel pipe concrete structure. In addition, a material having a high damping rate such as a viscous body, a viscoelastic body, a plastic body, or an elastic-plastic body can be inserted into the contact surface between the filled concrete 6 and the outer steel pipe 2 or the inner steel pipe pile 3. And all the processes are complete | finished by the above, and the installation structure of the marine structure 1 is completed.

  By constructing in this way, the offshore structure 1 can be firmly supported by the ground 201 and the support layer 210 on the seabed. Moreover, in the construction, only the lower end of the inner steel pipe pile 3 inserted into the outer steel pipe 2 is inserted into the ground 201 or the support layer 210 on the seabed, and the inner steel pipe pile 3 is inserted using the outer steel pipe 2 as a guide. Therefore, construction can be easily performed.

  In particular, since the rotary penetration pile 3 with the blade 3a at the lower end is penetrated into the ground 201 or the support layer 210 as the inner steel pipe pile 3, the pulling resistance of the inner steel pipe pile 3 can be increased by the lower blade 3a. . Therefore, even if the inner steel pipe pile 3 is reduced in depth, sufficient resistance can be exerted when a horizontal load or moment is applied to the top of the offshore structure 1. Moreover, since the rotation penetration pile 3 can exhibit a big pulling resistance and pushing resistance by making it penetrate in the ground 201 of the seabed, by utilizing the jack which supported the upper part of the rotation penetration pile 3, The level adjustment in the vertical direction and the level adjustment of the structure 1 can be easily performed, and high-precision construction is possible.

  Moreover, since the rotation penetration pile 3 with the blade | wing 3a can be previously inserted in the inside of the outer steel pipe 2, the rotation penetration pile 3 which is the inner steel pipe pile 3 is made into the ground of the seabed, using the outer steel pipe 2 as a guide. 201 can be penetrated, and it is possible to increase the efficiency and accuracy of on-site construction. Moreover, since the rotation penetration pile 3 can be inserted in the ground 201 by rotating it with the rotation penetration machine 120, at the time of construction, noise and vibration like a hammering pile are not generated, and environment-friendly construction is performed. It becomes possible. Moreover, since the rotation penetration pile 3 can be safely inserted into the ground 201 while offsetting the reaction force while the offshore structure 1 is suspended by a crane, the construction management can be easily performed.

  Moreover, by making the leg material a steel pipe concrete structure, the outer diameter of the outer steel pipe 2 can be increased and the thickness can be reduced, so that the buckling strength can be improved without increasing the weight. . Therefore, it is possible to realize a simple structure with a minimum of reinforcing materials such as horizontal materials, diagonal materials, bracing materials, and the like, and it is possible to reduce costs by using spiral steel pipes and ERW steel pipes.

  Further, when a material having a high damping rate such as a viscous body, a viscoelastic body, a plastic body, or an elastic-plastic body is inserted into the contact surface between the concrete 6 and the outer steel pipe 2 or the inner steel pipe pile 3, the outer steel pipe 2 or Since the relative displacement between the inner steel pipe pile 3 and the concrete 6 becomes possible, the material such as the viscous body and the viscoelastic body undergoes shear deformation, thereby increasing the attenuation rate of the structure. Moreover, the concrete 6 and the rotation penetration pile 3 can be unbonded by inserting the material such as the viscous body or the viscoelastic body between the concrete 6 and the rotation penetration pile 3, and as a result, the rotation penetration pile. It is possible to easily rotate 3 and pull it out, so that the structure can be easily removed.

  In addition, when facilitating the removal from the rear, the outer steel pipe 2 and the rotary penetrating pile 3 can be released from the joint, and by releasing the joint, the rotary penetrating pile 3 can be reversely inserted. It is better to be able to rotate in the direction (for example, unbonding steel pipe and concrete). By doing so, the rotary penetration pile 3 can be easily pulled out from the ground 201 by releasing the joint between the rotary penetration pile 3 and the outer steel pipe 2 and rotating the rotary penetration pile 3 in the direction opposite to that during penetration. Thus, the offshore structure 1 can be easily removed, and the removal cost can be reduced.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The change of the structure of the range which does not deviate from the summary of this invention, etc. are included.
For example, in the above-described embodiment, the example in which the cylindrical vertical plate is used as the joining member for interconnecting the leg members 2 has been described. However, the present invention is not limited to this, and the plate is simply a flat plate or twisted. Adjacent legs may be connected by a shaped plate. Further, the horizontal plate is not limited to two upper and lower horizontal plates, and three or more horizontal plates may be used.

DESCRIPTION OF SYMBOLS 1 Offshore structure 2 Leg material, outer steel pipe 3 Inner steel pipe pile, rotation penetration pile 3a Blade | wing 5 Open space 10 Virtual cylinder 11 Contact 20 Upper joint member 21 Cylindrical vertical cylindrical plate 22, 23 Horizontal plate 22a Through-hole 200 Ocean floor 201 Ground 210 Support layer L Center axis S Center line

Claims (8)

A solid obtained by twisting a polygonal frustum with a lower part and a narrowed upper part around its central axis is assumed to be a virtual basic shape, and straight legs are arranged along each oblique ridgeline of the solid. The center line of each leg or its extension line is configured to be in contact with a virtual cylinder centered on the central axis of the solid, and in the vicinity of the contact point between the virtual cylinder and the center line of each leg. While interconnecting the legs by a joining member, to secure an area surrounded by the legs below the height level where the joining member is arranged as an open space ,
A vertical plate along the vertical direction is provided as the joining member, and the legs are interconnected by joining the vertical plates to the legs along the vertical direction,
The vertical plate is a cylindrical or conical cylindrical tube;
The joining member includes upper and lower horizontal plates along the horizontal direction, the upper horizontal plate is joined to the upper part of the vertical plate, the lower horizontal plate is joined to the lower part of the vertical plate, and the upper and lower horizontal plates are joined. The legs are interconnected by passing the legs through a plurality of through-holes formed in each other, and joining the horizontal plate and the legs along the horizontal direction at the penetration portions. Offshore structures.   The offshore structure according to claim 1,
  The marine structure characterized in that the joining member is a disc-shaped horizontal plate disposed on upper and lower ends of the vertical cylindrical plate.   The offshore structure according to claim 1 or 2,
  The joining member is composed of the vertical cylindrical plate and the horizontal plates of the upper and lower rings.
  An offshore structure characterized in that the upper horizontal plate has a larger diameter than the lower horizontal plate. An installation structure for an offshore structure according to any one of claims 1 to 3 ,
The legs of the offshore structure are composed of an outer steel pipe and an inner steel pipe pile inserted into the outer steel pipe, the offshore structure is installed on the seabed, and the lower end of the inner steel pipe pile is inserted into the ground of the seabed. And the installation structure of the offshore structure characterized by integrally joining the said outer steel pipe and the inner steel pipe pile in that state. The offshore structure installation structure according to claim 4 ,
The inner steel pipe pile is composed of a rotating penetrating pile with a blade at the lower end, and the lower end penetrates into the ground of the sea floor by rotating the rotating penetrating pile by installing the marine structure on the sea floor, and the state installation structure of in marine structure, characterized in that joining the said outer steel pipe and the rotary penetration piles together. The marine structure installation structure according to claim 5 ,
The installation of the offshore structure characterized in that the outer steel pipe and the rotary penetrating pile can be unbonded and the rotating penetrating pile can be rotated in the direction opposite to the direction of penetration by releasing the joint. Construction. A installation structure of marine structure according to any one of claims 4-6,
A marine characterized in that the leg material has a steel pipe concrete structure by filling concrete in at least one of the space between the outer steel pipe and the inner steel pipe pile and the space inside the inner steel pipe pile. Structure installation structure. The marine structure installation structure according to claim 7 ,
A marine structure characterized in that a material having a high damping rate such as a viscous body, a viscoelastic body, a plastic body, or an elastic-plastic body is inserted into a contact surface between the filled concrete and the outer steel pipe or the inner steel pipe pile. Installation structure of things.

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