JP2019060227A - Construction method of jacket structure - Google Patents

Abstract

To provide a construction method of a jacket structure which can more efficiently construct a jacket structure at a predetermined position in an object water area, and can secure higher working safety.SOLUTION: A lower side positioning guide 8 is arranged in a water bottom ground 17 at the neighborhood position of a work frame 5 which is supported by the water bottom ground 17 and is installed on the water, an upper side positioning guide 7 connected to the work frame 5 is made to extend in a horizontal direction, a plurality of cylindrical followers 14 are positioned and erected at predetermined positions of the water bottom ground 17 with upper and lower positioning guides 7 and 8, mounting type excavators 9 are mounted on an upper end of each of the followers 14, the inside of each of the followers 14 is excavated at a predetermined position of the water bottom ground 17 with an excavation bit 11 mounted on a driving shaft 10 extending downward in the same period as installation holes 18, and a fixing part 2 of a jacket structure 1 is fixed to an upper end 3a of each of piles 3 that is inserted and embedded into each of the installation holes 18 to integrate each of the piles 3 and the jacket structure 1.SELECTED DRAWING: Figure 13

Description

  The present invention relates to a method of constructing a jacket structure, and more specifically, a jacket structure capable of more efficiently constructing a jacket structure at a predetermined position on a hard ground in a target water area and securing higher work safety. It relates to the construction method of

  There is known a method of constructing a jacket structure by fixing a jacket structure such as an ocean-going berth or a breakwater to the upper end of a plurality of piles placed in the underwater ground of a target water area (for example, a patent) Reference 1). In order to construct a jacket structure, a plurality of piles are sequentially driven on the water bottom ground. However, in the case of hard ground where it is difficult to place a pile with a hammer or the like, it is necessary to employ a drilled pile for excavating the hard ground and installing the pile. In this case, the drilling process is very long. If a shift occurs between the position of each pile installed and the fixing portion of the jacket structure corresponding to each pile, it is not possible to join both smoothly. Therefore, in order to construct the jacket structure at a predetermined position of the target water area more efficiently, it is also necessary to precisely drive each pile at a predetermined position.

  Also, the longer the drilling process, the more chances of encountering stormy weather. In order to ensure the safety of the work in rough weather, it is necessary to interrupt the digging process and to save the working equipment etc. to a safe position in advance, and a complicated task is also required to restart the digging process. Become. Therefore, there is room for improvement in constructing the jacket structure more efficiently and enhancing the safety of the operation.

JP, 2005-133485, A

  An object of the present invention is to provide a method of constructing a jacket structure capable of more efficiently constructing a jacket structure at a predetermined position of hard ground in a target water area and securing higher safety of work.

  In order to achieve the above object, according to the method of constructing a jacket structure of the present invention, a plurality of piles are embedded in a predetermined position of the underwater ground of the target water area, and the fixing portion of the jacket structure is formed at the upper end of each pile. In the method of constructing a jacket structure in which the pile structure and the jacket structure are integrated by fixing each other to construct the jacket structure at the predetermined position, the work platform supported on the water bottom ground is floated on the water A lower positioning guide on the bottom of the water bottom at a position near the work platform, and an upper positioning guide connected to the work platform and extending in the horizontal direction; Of the upper and lower positioning guides are positioned and erected at the predetermined positions by the upper positioning guide and the lower positioning guide, and the interiors of the respective followers extend downward. Mounted on the upper end of each of the followers, and a plurality of installation holes are simultaneously drilled at the predetermined positions using the respective mounted excavators. A plurality of the piles are embedded in the predetermined position by inserting the piles into the drilled installation holes.

  According to the present invention, a loading type excavating machine is mounted on the upper end of each of the plurality of followers set up at a predetermined position on the underwater ground of the target water area, and a plurality of loading type drilling machines are used at the same time The installation hole is excavated at a predetermined position on the underwater ground. Since a pile can be embedded by inserting and installing a pile in each excavated installation hole, the time required for the excavation process for embedding a plurality of piles can be shortened. By positioning each follower at a predetermined position by the upper positioning guide and the lower positioning guide, each installation hole is excavated at a predetermined position with high accuracy. Accordingly, since each pile is embedded at a predetermined position, it is possible to smoothly fix the embedded pile and the fixing portion of the jacket structure corresponding to each pile. Therefore, it is advantageous to construct the jacket structure at a predetermined position of the target water area more efficiently.

  In addition, if the installation hole gets rough during drilling, the on-board excavator and the follower are retracted to a safe place such as a work platform, and if the weather recovers, the on-board excavator and the follower will be recovered. It is sufficient to re-arrange the original position and resume drilling. Therefore, it is possible to ensure the safety of the work without complicated work. Furthermore, drilling a plurality of installation holes at the same time shortens the construction period, thereby reducing the chance of encountering stormy weather. This becomes more advantageous for the improvement of work efficiency and the improvement of work safety.

It is explanatory drawing which illustrates the jacket structure constructed | assembled by this invention by a side view. It is explanatory drawing which illustrates the jacket structure of FIG. 1 by planar view. It is explanatory drawing which illustrates the work platform and upper positioning guide which were installed in the object water area by a side view. It is explanatory drawing which illustrates the work platform and upper side positioning guide of FIG. 3 by planar view. It is explanatory drawing which illustrates a lower side positioning guide by side view. It is explanatory drawing which illustrates the lower side positioning guide of FIG. 5 by planar view. It is explanatory drawing which illustrates the process of installing a lower side positioning guide in water bottom ground by a side view. It is explanatory drawing which illustrates the process of positioning and installing a casing in the predetermined position of water bottom ground by a side view. It is explanatory drawing which illustrates the process of positioning and installing a follower on the upper end of the casing of FIG. 8 by a side view. It is explanatory drawing which illustrates the process which is driving the casing of FIG. 9 in the water bottom ground by a side view. It is explanatory drawing which illustrates the process of mounting a mounted excavator to the upper end part of each follower in a side view. It is explanatory drawing which makes the inside of a follower the longitudinal cross-section, and illustrates the mounted excavator of FIG. It is explanatory drawing which illustrates the installation hole excavated at the predetermined position of the water bottom ground using each on-board type excavating machine by a side view. It is explanatory drawing which illustrates the process of pulling up a follower on the water after a digging of an installation hole by side view. It is explanatory drawing which illustrates the process of inserting a pile in each installation hole by a side view. It is explanatory drawing which illustrates the process of pulling up a lower positioning guide on water on a side view. It is explanatory drawing which illustrates the process of positioning and fixing the fixing | fixed part of a jacket structure to the upper end part of each pile by a side view. It is explanatory drawing which illustrates the upper positioning guide supported by the work stand and reinforcement pile by a side view. FIG. 19 is an explanatory view illustrating the work platform and the upper positioning guide of FIG. 18 in a plan view. It is an explanatory view which illustrates another work stand and upper positioning guide used for the present invention by plane view. FIG. 21 is an explanatory view illustrating the work platform and the lower positioning guide of FIG. 20 in a front view; The installation hole excavated at a predetermined position in the underwater ground using a mounted excavator mounted on the upper end of the follower erected using the upper positioning guide and the lower positioning guide of FIG. 21 is illustrated in a side view FIG.

  Hereinafter, an example of the procedure of the method for constructing a jacket structure of the present invention will be described based on the embodiment shown in the drawings.

  As exemplified in FIGS. 1 and 2, the jacket structure 1 constructed according to the present invention is an upper end portion of a plurality of piles 3 embedded at a predetermined position (a predetermined target position) of the underwater ground 17 in the target water area. The fixing portion 2 of the jacket structure 1 is fixed to 3a so as to be integrated with the respective piles 3. Although the number of piles 3 is four in this embodiment, the number of piles 3 is preferably, for example, three or more, and three or four is optimal.

  The jacket structure 1 is, for example, a truss structure formed of a plurality of steel pipes or the like. The jacket structure 1 may be, for example, an offshore berth, a breakwater, or a wind power generation facility having a wind turbine. In the jacket structure 1 of this embodiment, the lower end portions of the four legs are the fixing portion 2. Since the jacket structure 1 is formed in advance in a factory or the like, the arrangement of the fixing portions 2 (the distance between the fixing portions 2) is fixed without any change.

  Each pile 3 is inserted into the installation hole 18 formed at a predetermined position of the underwater ground 17, and is installed in a state where the upper end 3 a protrudes above the underwater ground 17. A cylindrical casing 4 is internally fitted at the upper end of the installation hole 18. In this embodiment, since the vicinity of the surface of the underwater ground 17 is a soft layer and the deeper region is a hard layer such as rock, the inner circumferential surface of the installation hole 18 in the soft layer is reinforced by the casing 4 . A grout 19 intervenes between the installation hole 18 and the inner peripheral surface of the casing 4 and the outer peripheral surface of the pile 3. The pile 3 is more firmly fixed to the underwater ground 17 by the grout 19.

  Recesses are formed in the upper end portions 3a of the respective stakes 3, and the fixing portions 2 corresponding to the respective recess portions are inserted and fixed. The structure is not limited to this structure, as long as the corresponding fixing portion 2 can be fixed to the upper end portion 3 a of each pile 3. For example, a recess may be formed in each fixing portion 2 and the upper end 3a of the pile 3 may be inserted into each recess so that the fixing portion 2 is fixed to the upper end 3a.

  Hereinafter, an example of the procedure of constructing the jacket structure 1 will be described.

  First, the work rack 5 illustrated in FIGS. 3 and 4 is installed on the water of the target water area where the jacket structure 1 is to be constructed. Specifically, the required number of support piles 6 are erected on the water bottom ground 17, and the work support racks 5 are supported on the water by the support piles 6. Lifting mechanisms 6a are installed on the support piles 6, respectively, and the work gantry 5 can be moved up and down by the lifting device 6a. Therefore, the work gantry 5 can be constantly maintained at the water position. For example, JUV (Jack up vessel) is used as the support pile 6 and the elevation mechanism 6a.

  A crane 15 is installed on the work stand 5. Further, an upper positioning guide 7 extending in the horizontal direction is connected to the work stand 5. The upper positioning guide 7 can extend outward from the work rack 5 when necessary, and has, for example, a frame structure.

  The upper positioning guide 7 has a plurality of pile guides 7a and one central guide 7b. Each pile guide part 7a is a rectangular cylinder shape which opened the upper and lower sides, and is arrange | positioned in the predetermined position which embeds each pile 3 in planar view. The arrangement and shape of each pile guide portion 7a can be adjusted by moving or changing the constituent members. The central guide portions 7 b are disposed at positions of central portions of the pile guide portions 7 a in a plan view, and are hollows in a rectangular shape in a plan view. The upper positioning guide 7 is positioned and installed using position information acquired by a DGPS device or the like. As described later, the upper positioning guide 7 only functions as a guide for positioning the follower 14 and the pile 3, a member acting against waves acting on the follower 14 and a current. That is, the upper positioning guide 7 is not intended to bear and support the weight of the follower 14, the pile 3, and the loading type excavating machine 9 described later. Therefore, the upper positioning guide 7 does not have to have a thick rigid structure.

  The lower positioning guide illustrated in FIGS. 5 and 6 is disposed on the water bottom ground 17 at a position near the work rack 5. The lower positioning guide 8 includes a plurality of pile guides 8a. Each pile guide portion 8a is in the form of a cylinder open at the top and bottom. The lower positioning guide 8 has a frame structure in which the respective pile guides 8a are connected by a frame. Therefore, the arrangement of the respective pile guide portions 8a (the distance between the pile guide portions 8a) is fixed without any change. The arrangement of each pile guide portion 8a is set to correspond to the arrangement of the pile 3 to be buried in a plan view.

  In this embodiment, each pile guide portion 8a has a landing portion 8b which advances and retracts in the vertical direction on its bottom surface. The lower positioning guide 8 is structured to support the weight acting on the lower positioning guide 8. Each landing portion 8 b can be made to project downward from the bottom surface of the pile guide portion 8 a by a desired amount of projection by advancing and retracting in the vertical direction by a fluid cylinder or the like. Each landing portion 8 b lands on the underwater ground 17.

  Above the lower positioning guide 8, a lifting guide frame 8 c is connected by a wire. The hanging guide frame 8c is disposed at the position of the central portion in a plan view of each pile guide portion 8a. The hanging guide frame 8c has a rectangular shape in plan view so as to fit in the central guide portion 7b so as to be able to move freely according to the shape (recession of a rectangular shape) of the central guide portion 7b in plan view. The hanging guide frame 8a and the central guide portion 7b are formed such that the shapes in plan view with each other correspond in this manner.

  As illustrated in FIG. 7, the lower positioning guide 8 is suspended by the suspension wire 16 and installed on the underwater ground 17 using a crane 15. At this time, the lower positioning guide 8 is moved downward to position each landing portion 8b while the lower positioning guide 8 is positioned while positioning the position of the lower positioning guide 8 in plan view so that the hanging guide frame 8c is fitted into the central guide portion 7b. Land at 17. At the same time, the position of the lower positioning guide 8 is finely adjusted by using the mooring cord 8e connected to the ship 8d fixed in position at sea by DPS (Dynamic Positioning System) or anchor. As described above, by using the hanging guide frame 8c and the central guide portion 7b as guides, and performing the above-mentioned fine adjustment, each pile guide portion 8a is at a predetermined position where the respective pile 3 is embedded in a plan view It becomes easy to place on. When the lower positioning guide 8 is installed, an underwater positioning system such as DGPS, an underwater acoustic positioner, or an inclinometer is used.

  If the surface of the underwater ground 17 on which the lower positioning guide 8 is arranged is not flat or the like, the amount of downward projection of the at least one landing portion 8b from the bottom surface of the pile guide portion 8a is adjusted as appropriate. As a result, the lower positioning guide 8 can be stably disposed horizontally on the underwater ground 17.

  Then, as illustrated in FIG. 8, the casing 4 such as a steel pipe is disposed at a predetermined position where the piles 3 are embedded in a plan view. Specifically, the casing 4 is suspended by the suspension wire 16 and inserted into the respective pile guide portions 8 a using the crane 15 to be positioned at a predetermined position and installed on the underwater ground 17.

  Next, as illustrated in FIG. 9, the cylindrical follower 14 is disposed at a predetermined position where the piles 3 are embedded in a plan view. A steel pipe or the like can be used as the follower 14. The follower 14 and the casing 4 have substantially the same inner diameter and outer diameter.

  A specific procedure for placing the followers 14 in position is to suspend the followers 14 by the suspension wires 16 and place them on the upper end of the casing 4 corresponding to the respective followers 14 using the crane 15. At this time, the follower 14 is moved downward and disposed at the upper end of the casing 4 while the position of the follower 14 in plan view is positioned by inserting the follower 14 into the corresponding pile guide portions 7a and 8a. By using the pile guides 7a and 8a as guides in this manner, it becomes easy to arrange the respective followers 14 at predetermined positions where the respective piles 3 are buried in a plan view.

  The casing 4 and the followers 14 disposed at the upper end of the casing 4 are detachably connected to each other by a guide and other fixing members. As in this embodiment, the casing 4 and the follower 14 may not be separately disposed at predetermined positions, but may be disposed at predetermined positions in a state where they are detachably connected on water and integrated in advance. In this case, the integral body of the casing 4 and the follower 14 is positioned and disposed at a predetermined position using the pile guides 7a and 8a as guides as described above.

  Next, as illustrated in FIG. 10, a hammer 13 suspended by the suspension wire 16 of the crane 15 is installed at the upper end of each follower 14 and the casing 4 is embedded in the underwater ground 17 by impact with the hammer 13 . That is, the casing 4 is buried in the underwater ground 17 until it reaches the hard layer. The respective followers 14 are positioned by the pile guide portions 7a and 8a, so that the casing 4 can be accurately inserted into the predetermined position. As described above, the plurality of followers 14 are positioned at a predetermined position on the underwater ground 17 in a plan view and erected using the upper positioning guide 7 and the lower positioning guide 8.

  Next, as illustrated in FIG. 11, mounted on the upper end portion of each follower 14 is a mounted excavator (Pile top drilling rig) suspended by the suspension wire 16 of the crane 15. As illustrated in FIG. 12, the mounted excavator 9 rotates the drive shaft 10 extending downward inside the follower 14, the digging bit 11 attached to the lower end of the drive shaft 10, and the drive shaft 10. And a drive source 9a. The mounted excavator 9 is removably connected to the follower 14 by a clamp member or the like. Since the drive shaft 10 is a tube, its inside is a through hole 10a extending in the longitudinal direction of the tube. This pipe body (drive shaft 10) is added according to the progress of excavation, but this addition work can be performed using a small crane provided in the on-board type excavating machine 9, so It is not necessary to use the installed crane 15.

  Each mounted excavator 9 excavates an installation hole 18 of a predetermined depth at a predetermined position of the underwater ground 17 by means of an excavating bit 11 which is rotationally driven by rotating the drive shaft 10. Soils and the like generated at the time of excavation are discharged onto water through the through holes 10 a of the drive shaft 10 by the reverse reflux generated by the air injected by the air compressor 12. The respective installation holes 18 are excavated at the same time by operating the on-board excavators 9 mounted on the respective followers 14. Basically, each mounted excavator 9 is operated under the same conditions.

  Heretofore, since it was a general procedure to excavate one installation hole 18 sequentially, in the construction of constructing the jacket structure 1, it takes a lot of time to excavate the required number of installation holes 18 It was Therefore, as in this embodiment, by excavating the required plurality of installation holes 18 at the same time, it is possible to significantly shorten the construction period. Note that excavating the installation holes 18 at the same time does not only mean making the period from the start of excavation of each installation hole 18 to the completion of excavation substantially the same, but the drilling start time of each installation hole 18 Are substantially the same, or it means that the drilling periods of the respective installation holes 18 overlap. For example, the loadable excavator 9 is sequentially mounted on each of the followers 14, and as soon as the loadable excavator 9 is mounted on the follower 14, the loadable excavator 9 is operated. The installation hole 18 is drilled at the same time.

  Depending on the ground condition (variation in hardness) of the underwater ground 17 which each of the loading type excavators 9 is digging, there may be variations in the completion of drilling of the respective installation holes 18. However, according to this embodiment, the time required for the step of excavating the required number of installation holes 18 can be reliably shortened compared to the conventional procedure of excavating one installation hole 18 sequentially. In this embodiment, the casing 4 is embedded in the soft layer of the underwater ground 17. That is, it is avoided that the inner peripheral surface of the installation hole 18 of a soft layer falls down by this casing 4, and the installation hole 18 can be excavated stably.

  After the drilling of the installation holes 18 is completed as illustrated in FIG. 13, the tubes constituting the respective drive shafts 10 are removed and recovered, and the drilling bit 11 is also recovered. The connection between the on-board excavator 9 and the follower 14 is released, and the on-board excavator 9 is lifted by the crane 15 and removed from the follower 14. Further, the connection between each follower 14 and the casing 4 is released, and the follower 14 is lifted and removed from the casing 4 using a crane 15 as illustrated in FIG. 14.

  After removing the respective followers 14 from the casing 4, as illustrated in FIG. 15, the respective piles 3 are suspended by the suspension wires 16, and the installation holes 18 corresponding to the respective piles 3 are insert. Since the inner diameter of the casing 4 is set larger than the outer diameter of the pile 3, the pile 3 can be inserted into the installation hole 18 by inserting the pile 3 into the casing 4. At this time, the pile 3 is moved downward and inserted into the installation hole 18 while the position of the pile 3 in plan view is positioned so as to be inserted into the corresponding pile guides 7a and 8a. By utilizing the pile guide portions 7a and 8a as a guide in this manner, it becomes easy to embed each pile 3 in a predetermined position in plan view. Further, it is possible to finely adjust the position by mounting a spacer projecting radially outward on the circumferential surface of the pile 3 on the water and inserting the spacer into the upper part with the stopper attached and inserting it into the casing 4.

  After each pile 3 is inserted into the installation hole 18, grout 19 is injected between the inner peripheral surface of the installation hole 18 (and the casing 4) and the outer peripheral surface of the pile 3 and cured for a predetermined time. Each of the piles 3 is firmly fixed to the underwater ground 17 via the grout 19. Next, as illustrated in FIG. 16, the lower positioning guide 8 is lifted and removed using a crane 15. Thereby, the pile 3 will be in the state embedded at each installation hole 18 by which the casing 4 was internally fitted by the upper end part.

  Next, as illustrated in FIG. 17, the fixing portion 2 of the jacket structure 1 is fixed to the upper end portion 3 a of each pile 3, and the pile 3 and the jacket structure 1 are integrated. Specifically, for example, using the crane 21 mounted on the work ship 20, the jacket structure 1 is suspended via the suspension wire 21a. Then, positional information of the jacket structure 1 is sequentially acquired by the guidance of the DGPS device and the diver, etc., positioned at a predetermined position, and moved downward.

  Since each pile 3 is accurately embedded at a predetermined position, the fixing portion 2 corresponding to each pile 3 can be smoothly positioned and fitted to the upper end portion 3 a of each pile 3. By fixing the fixing portion 2 to the upper end portion 3a of each pile 3 fitted, the jacket structure 1 in which both are integrated is constructed at a predetermined position.

  In this manner, the installation holes 18 can be excavated at the same time, and the necessary piles 3 can be embedded by inserting the piles 3 into the installation holes 18, so that the piles 3 can be embedded. The time required for the drilling process can be significantly reduced. Further, by positioning each follower 14 at a predetermined position by the upper positioning guide 7 and the lower positioning guide 8, each installation hole 18 can be excavated at a predetermined position with high accuracy. Accordingly, the corresponding fixing portions 2 can be smoothly fixed to the respective piles 3 embedded in the respective installation holes 18, so that the jacket structure 1 can be constructed more efficiently at the predetermined position. It is advantageous to

  In the case where the strong weather such as high winds or waves get high during the drilling of the respective installation holes 18, the respective mounted excavators 9 and the followers 14 are evacuated to a safe place on the water such as the work platform 5 or the like. When the weather recovers, the onboard excavators 9 and the followers 14 are repositioned to their original predetermined positions to resume drilling. Since the loading type excavating machine 9 and the follower 14, and the follower 14 and the casing 4 are respectively detachably connected, their evacuation and resumption operations are mainly performed using the crane 15 and quickly performed without complicated operations. be able to. Therefore, the safety of work can be secured. Of course, even in rough weather, depending on the level of strong wind and waves, safety can be ensured by the resistance of the upper positioning guide 7, the lower positioning guide 8 and the follower 14, and in this case, it is not necessary to perform the evacuation operation.

  Furthermore, drilling a plurality of installation holes 18 at the same time shortens the construction period, thereby reducing the chance of encountering stormy weather. Therefore, it becomes more advantageous for the improvement of work efficiency and the improvement of work safety. According to this embodiment, more remarkable effects can be obtained at a construction site where weather conditions are severe.

  Depending on the condition and strength of the underwater ground 17, as shown in FIGS. 18 and 19, it is also possible to connect a reinforced pile 7c erected on the underwater ground 17 to the projecting tip of the upper positioning guide 7. By providing this reinforcement pile 7c, the weight of the on-board excavator 9, the follower 14 and the like can be supported, and the safety of the work is improved.

  In the case where only the hard layer is present with almost no soft layer on the underwater ground 17, the casing 4 can be made unnecessary. In this case, using the shorter casing 4 in the embodiment described above, the respective followers 14 are arranged at predetermined positions and erected on the underwater ground 17 in the same procedure. Thus, the casing 4 is mainly used as an insertion guide for the pile 3.

  In the embodiment described above, each pile 3 is embedded substantially perpendicularly to the underwater ground 17, but may be embedded at a predetermined inclination angle. In this case, the pile guide portions 7a and 8a are formed to be inclined so as to correspond to the predetermined inclination angle.

  The work rack 5 illustrated in FIGS. 20 to 22 can also be used. The work rack 5 has a structure having an opening 5a communicating with the central portion in the top and bottom in plan view. Further, unlike this embodiment, the crane 15 is not installed on the work stand 5. The other configuration is substantially the same as that of the work stand 5 illustrated in the previous embodiment. An upper positioning guide 7 is installed in the opening 5a.

  When this work stand 5 is used, the lower positioning guide 8 is pulled from the side of the work stand 5 supported on the water by the support pile 6 into the central portion of the work stand 5 using a winch or the like. The procedure of the subsequent work process is the same as that of the previous embodiment. As illustrated in FIG. 21, the lower positioning guide 8 drawn into the central portion of the work platform 5 is installed at a predetermined position on the underwater ground 17 using, for example, a crane 21 mounted on the work vessel 20.

  Thereafter, as illustrated in FIG. 22, the respective installation holes 18 are drilled at the same time using the on-vehicle type excavators 9. Thereafter, the fixing portion 2 is fixed to the upper end portions 3a of the plurality of piles 3 inserted and embedded in the respective installation holes 18, so that the jacket structure 1 is constructed at a predetermined position. In a water area where the working environment such as wave wind is moderate and the water depth is relatively shallow, the crane 15 mounted on the work ship 20 can be sufficiently utilized instead of the crane 15 installed on the work rack 5.

DESCRIPTION OF SYMBOLS 1 Jacket structure 2 Fixing part 3 Pile 3a Upper end part 4 Casing 5 Work stand 5a Opening 6 Support pile 6a Lifting mechanism 7 Upper positioning guide 7a Pile guide part 7b Central guide part 7c Reinforcement pile 8 Lower positioning guide 8a Pile guide part 8b Landing portion 8c Hanging guide frame 8d Ship 8e Mooring cable 9 Mounted excavating machine 9a Drive source 10 Drive source 10 Drive shaft 10a Through hole 11 Drilling bit 12 Air compressor 13 Hammer 14 Follower 15 Crane 16 Hanging wire 17 Water bottom ground 18 Installation hole 19 Grout 20 Work ship 21 crane 21a hanging wire

Claims (4)

A plurality of piles are embedded at a predetermined position of the underwater ground of the target water area, and the fixing portion of the jacket structure is fixed to the upper end of each of the piles, thereby integrally integrating the pile and the jacket structure. In the method of constructing a jacket structure, the jacket structure is constructed in the predetermined position by
The work platform supported on the waterbed ground is installed on water, the lower positioning guide is disposed on the waterbed ground at a position near the work platform, and the upper side is connected to the work platform and extends in the horizontal direction A positioning guide is installed, and a plurality of cylindrical followers are positioned at the predetermined position and erected by the upper positioning guide and the lower positioning guide, and the interiors of the respective followers are extended downward. A mounted excavator having a drive shaft for driving an drilling bit is mounted on the upper end of each of the followers, and a plurality of installation holes are simultaneously drilled at the predetermined positions using the mounted excavators. And a method of constructing a jacket structure characterized in that a plurality of said piles are embedded in said predetermined position by inserting said piles into each of said drilled installation holes.   The lower positioning guide has a plurality of landing portions advancing and retreating in the vertical direction on its bottom surface, and the respective landing portions are made to land on the water bottom ground with a desired protrusion amount downward from the bottom surface, The method for constructing a jacket structure according to claim 1, wherein the lower positioning guide is disposed on the water bottom ground.   A cylindrical casing is detachably connected to a lower end of each of the followers, and the respective followers are erected at the predetermined positions in a state where the respective casings are embedded in the water bottom ground. The construction method of the jacket structure as described in 2.   The lower positioning guide is installed on the underwater ground using a crane installed on the work platform, each follower is erected at the predetermined position, and each pile corresponding to the installation hole The method for constructing a jacket structure according to any one of claims 1 to 3, wherein the jacket structure is inserted.

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