JP5588929B2 - Offshore structure construction method and offshore structure - Google Patents

Description

  The present invention relates to a construction method for offshore structures such as breakwaters, quay walls, revetments, and offshore structures.

  Conventionally, when constructing marine structures such as breakwaters, quay walls, revetments, the caisson method is often used. In the caisson method, a box-shaped caisson with a concrete bottom slab and a side wall slab is produced at an onshore production yard or floating dock, and this caisson is launched and towed to the construction site, and the sea floor is flattened. Settling on a bottom foundation such as a rubble mound constructed to level. Then, crushed stones and the like are put into the caisson and filled, and rooting work and scouring prevention work are performed before and after the caisson to construct marine structures such as breakwaters, quay walls and revetments.

  However, in the construction method of the marine structure using the caisson method, because the caisson is made of concrete and box-shaped, it is difficult to ensure stability when towing to the construction site, floating the caisson, It is easily affected by sea conditions such as waves. For this reason, there is a problem that it is difficult to apply to construction of long-distance offshore structures that take several hours or days for towing, such as remote islands.

  In addition, in order to stably sink the caisson, it is necessary to construct a bottom foundation using a rubble mound or the like, and the construction of this bottom foundation requires a great deal of labor and cost. Furthermore, if the sea conditions are rough, rubble mounds may be washed away.

  In addition, a large lifting pressure acts between the bottom of the water bottom and the bottom of the caisson until the caisson is deposited on the bottom of the water bottom. And it takes a lot of time until the caisson is laid and filled, and during this time, the calm days of the sea conditions need to be continuous in order to keep the caisson in a stable state. Also from this point, there was a problem that construction was greatly restricted by sea conditions such as waves.

  On the other hand, Patent Document 1 uses a working floating body and a forming frame, suspends the caisson side wall plate (wall surface) at the construction site sequentially, and hangs it down to the sea floor. A construction method for constructing a caisson by placing bottom slab concrete is disclosed. In this construction method, it is not necessary to tow a box-shaped caisson, compared to the construction method of the offshore structure using the conventional caisson method, and in addition, the side wall plate is constructed in sequence and suspended at the bottom of the sea. Since the bottom plate is formed, it is possible to suppress the influence of sea conditions such as waves.

JP 2001-214419 A

  However, even in the construction method disclosed in Patent Document 1, it is difficult to transport the working floating body over a long distance, and even if a carriage is used, a hoisting ship for draining water is necessary. For this reason, there was still a problem that the work could not be done unless the sea conditions were calm.

  Moreover, there is a possibility that the working floating body and the forming frame body may be destroyed in a place where sea conditions such as waves are rough. In particular, since a frame for molding is installed on the site and concrete is placed to construct a side wall version of the caisson, it takes a lot of time to manufacture the side wall version. There is a possibility that the forming frame body is broken.

  In order to solve the above problems, the present invention provides the following means.

  The construction method of the offshore structure of the present invention comprises a mold manufacturing process for manufacturing an upper mold and a lower mold, which are provided with an internal space surrounded by at least a side wall plate, and are arranged on the top and bottom, and a lower end attached to the seabed. Form support process for supporting the upper and lower molds so that they can be moved up and down on a plurality of support pillars standing upright and placed above the sea level, and lowering the lower molds to the sea floor And forming a lower structure by placing concrete in the inner space of the lower mold, and lowering the upper mold to place the upper mold on the lower structure, and arranging the upper mold And an upper structure forming step for forming an upper structure integrated with the lower structure by placing concrete in the inner space.

  In the present invention, for example, an upper mold and a lower mold are manufactured at an on-site factory or a production yard, and a base boat is mounted in a state where a plurality of support pillars are vertically stacked and attached to the upper and lower molds. Can be transported to the construction site. At the construction site, with the upper column and the lower frame attached, the support column is lowered into the sea and the lower end is settled on the sea floor. The formwork can be supported in a state of being arranged above the sea level.

  Thereby, the influence of sea conditions, such as a wave, can be restrained small, while conveying the upper stage formwork and lower stage formwork which were manufactured at the formwork manufacturing process to a construction place. Also, in the mold support process, the upper and lower mold forms are supported by a plurality of support pillars at a predetermined position (installation point) at the construction site and above the sea level. It is possible to prevent the external force such as waves from acting on the upper and lower molds, and to reduce the influence of sea conditions, thereby arranging the upper and lower molds at predetermined positions.

  Then, in the lower structure forming step, when the lower formwork is lowered to the seabed and concrete is placed therein, for example, by opening the bottom part and forming the lower formwork, the concrete is placed on the seabed. The lower structure can be formed without leveling the bottom of the sea flat, that is, without providing a water bottom foundation such as a rubble mound as in the prior art. At this time, the upper formwork is left, the lower formwork is lowered, concrete is placed, and the lower structure in which the marine structure to be constructed is divided is constructed in advance. Since the area that receives external forces such as waves is smaller than that of conventional caisson, it is possible to suppress the influence of sea conditions such as waves when setting this lower formwork (when constructing the lower structure) .

  Next, in the upper structure forming step, the upper formwork is lowered and stacked on the lower structure, and the concrete is placed in the inner space of the upper formwork, so that the upper structure integrated with the lower structure, and thus An offshore structure can be formed. Also, at this time, by constructing the upper structure in which the offshore structure to be constructed is divided after the lower structure, the area that receives external force such as waves of the upper formwork becomes smaller than the conventional caisson. Even when the upper formwork is laid down (when the upper structure is constructed), it is possible to suppress the influence of sea conditions such as waves.

  As a result, compared to the conventional caisson method and the construction method disclosed in Patent Document 1, the influence of sea conditions such as waves can be reduced, and even in remote areas such as remote islands, breakwaters, wharves, revetments, etc. It becomes possible to construct the marine structure in a short time efficiently.

  Moreover, in the construction method of the offshore structure of this invention, it is desirable that the said lower stage form is formed by attaching the said side wall version to the frame main body of a truss structure.

  In this invention, when the lower mold is provided with a truss structure frame body, it is possible to form a lower mold having excellent strength characteristics, and when an external force such as a wave acts on the lower mold. The external force can be transmitted to the plurality of support pillars through the frame body. Thereby, it becomes possible to perform construction in a more stable state.

  In addition, even when the frame body that enhances the strength characteristics is disposed in the inner space surrounded by the side wall plate to form the lower mold, the frame body has a truss structure, so the inner space of the lower mold When the concrete is placed in the concrete, the fluidity and filling properties of the concrete are not hindered, and the interior space can be filled (concretely) with good concrete.

  Furthermore, in the construction method of the offshore structure of the present invention, a leakage preventing means is provided on the outer peripheral side of the lower mold frame so that the concrete is placed in the internal space and is pressed against the concrete to be in close contact with the seabed. It is more desirable.

  In this invention, the sea floor is flattened by the leak prevention means such as the leakage prevention sheet provided on the outer peripheral portion side of the lower mold frame being pressed against the concrete placed in the inner space of the lower mold frame and closely contacting the sea floor. Without being leveled, the internal space and the outside of the lower mold can be shut off with the leak preventing means interposed therebetween. As a result, it is possible to prevent the concrete placed in the internal space of the lower mold form from leaking to the outside, and it is possible to suitably construct the lower structure and thus the marine structure.

  In the offshore structure construction method of the present invention, the upper formwork is formed with an internal space surrounded by at least the side wall plate and the bottom plate, and is disposed above the sea surface and supported by the support column. More preferably, seawater is pumped and poured into the inner space of the upper mold in the state of being formed.

  In the state where the upper and lower molds are supported by multiple support pillars and arranged above the sea level, external forces such as waves mainly act on the support pillars, and the upper, lower, and support pillars It will resist this external force by its own weight. And in this invention, the resistance to external force can be increased by the weight of the injected seawater by pumping and pouring seawater into the internal space of the upper formwork arranged above the sea surface. This makes it possible to achieve a more stable state.

  Moreover, in the construction method of the offshore structure of the present invention, the upper mold form and the lower mold form are constructed using a bottomed trolley in a state where the plurality of support pillars are attached while being laminated in the vertical direction. It is desirable to transport to

  In the present invention, the upper formwork and the lower formwork are transported to a construction site by a bottomed trolley, seawater is poured into the hull of the bottomed craft, and the bottom of the ship is grounded to the seabed. The upper mold frame and the lower mold frame can be positioned and held at the positions. And by lowering the support column into the sea and bottoming the bottom to the seabed, the upper and lower molds are supported by a plurality of standing support columns so that they can be raised and lowered, so that the upper and lower molds can be reliably and easily supported. It becomes possible to arrange the formwork at a predetermined position (installation point) at the construction site and in a state of being arranged above the sea surface.

  Further, in the construction method of the offshore structure of the present invention, the upper mold form and the lower mold form are installed using a semi-submersible trolley in a state where the plurality of support pillars are attached while being stacked one above the other. You may make it carry to.

  In this invention, for example, a semi-submersible trolley transports the upper and lower molds to the construction site, injects seawater into the hull of the semi-submersible trolley, and the upper and lower molds are placed on the sea surface. Sink a semi-submersible trolley until it floats. Then, the upper formwork and the lower formwork that have been lifted are towed to a predetermined position at the construction site by a dredger, the support pillar is lowered into the sea, the lower end is settled on the seabed, and the upper formwork is installed by a plurality of standing support pillars. The lower mold is supported so that it can be raised and lowered. Further, the upper and lower molds are moved up and down from the sea surface. As a result, it is possible to reliably and easily dispose the upper and lower molds at predetermined positions (installation points) at the construction site and above the sea level.

  The offshore structure of the present invention is constructed by using the above-described offshore structure construction method.

  In this invention, since an offshore structure is built using the construction method of the above-described offshore structure, it is possible to obtain the operational effects of the above-described offshore structure construction method.

  According to the marine structure construction method and marine structure of the present invention, the upper structure and the lower structure are constructed in order by dividing the marine structure to be constructed using the upper and lower molds. Therefore, it is possible to minimize the influence of sea conditions such as waves, and it is possible to efficiently construct marine structures such as breakwaters, quay walls and revetments even in remote areas such as remote islands.

It is a figure which shows the offshore structure which concerns on one Embodiment of this invention. It is a figure which shows the upper stage formwork, lower stage formwork, support pillar, and 1st raising / lowering jack which are used with the construction method of the offshore structure which concerns on one Embodiment of this invention. FIG. 3 is a view taken along line X1-X1 in FIG. FIG. 3 is a view taken in the direction of arrows X2-X2 in FIG. 2 and is a plan view showing a lower mold used in the method for constructing an offshore structure according to an embodiment of the present invention. It is a figure which shows the leak prevention sheet (leak prevention means) attached to the lower-stage formwork used with the construction method of the offshore structure which concerns on one Embodiment of this invention. It is a X3-X3 line arrow figure of FIG. 2, and is a top view figure which shows the upper stage formwork used with the construction method of the offshore structure which concerns on one Embodiment of this invention. It is a figure which shows the state which manufactured the upper stage formwork and the lower stage formwork in the construction method of the offshore structure which concerns on one Embodiment of this invention. In the construction method of an offshore structure according to an embodiment of the present invention, the upper mold frame and the lower mold frame are stacked and arranged, and the support column, the first lifting jack, and the second lifting jack are attached and integrated. FIG. It is a figure which shows a support pillar, a 1st raising / lowering jack, and a 2nd raising / lowering jack. It is a figure which shows the state which supported the upper stage form (lower stage form) on the support pillar, and was raised / lowered. In the construction method of the offshore structure which concerns on one Embodiment of this invention, it is a figure which shows the state which loaded the upper stage formwork and the lower stage formwork which were integrated on the bottom type | formula carrier. In the construction method of the offshore structure which concerns on one Embodiment of this invention, it is a figure which shows the state which is conveying the upper stage formwork and the lower stage formwork with a bottomed type carrier. In the construction method of the offshore structure which concerns on one Embodiment of this invention, it is a figure which shows the state which moored the bottom type trolley which conveyed the upper stage formwork and the lower stage formwork to the construction place. In the construction method of the offshore structure which concerns on one Embodiment of this invention, it is a figure which shows the state which made the bottom type trolley bottom the seabed. In the construction method of the offshore structure which concerns on one Embodiment of this invention, it is a figure which shows the state which settled the lower end of the support pillar to the seabed. In the construction method of the offshore structure which concerns on one Embodiment of this invention, it is a figure which shows the state which promoted the upper stage formwork and the lower stage formwork. In the construction method of the offshore structure which concerns on one Embodiment of this invention, it is a figure which shows the state which the bottom type trolley is moving. In the construction method of the offshore structure which concerns on one Embodiment of this invention, it is a figure which shows the state which lowered | hung the lower stage formwork to the seabed. In the construction method of the offshore structure which concerns on one Embodiment of this invention, it is a figure which shows the state which has poured concrete into the internal space of the lower stage | form mold | type dropped to the seabed. In the construction method of the offshore structure which concerns on one Embodiment of this invention, it is a figure which shows the state which dropped and arranged the upper stage | mold form on the lower stage formwork. In the construction method of the offshore structure which concerns on one Embodiment of this invention, it is a figure which shows the state which has poured concrete into the internal space of the lowered upper formwork. It is the example of a change of the construction method of the offshore structure which concerns on one Embodiment of this invention, and shows the state which is loading the integrated upper stage formwork and lower stage formwork on the semi-submersible trolley, and is carrying to the construction place vicinity. FIG. It is an example of a change in the construction method of an offshore structure according to an embodiment of the present invention, and the upper formwork and the lower formwork carried by a semi-submersible trolley to the vicinity of the construction place are towed to a predetermined position of the construction place by a tug FIG. It is an example of a change in the construction method of an offshore structure according to an embodiment of the present invention, and the lower end of the support column that supports the upper and lower molds towed up and down to a predetermined position of the construction site on a dredger on the seabed. It is a figure which shows the state made to bottom. It is a modification of the construction method of the offshore structure which concerns on one Embodiment of this invention, and is a figure which shows the state which promoted the upper stage formwork and the lower stage formwork.

  Hereinafter, a marine structure construction method according to an embodiment of the present invention and a marine structure constructed by the construction method will be described with reference to FIGS.

  First, the offshore structure of the present embodiment is a breakwater, a quay, a revetment, etc., and is a gravity type offshore structure that resists external forces such as waves by a resistance force due to its own weight (gravity). As shown in FIG. 1, this offshore structure A includes a lower mold 1 disposed in contact with the seabed S <b> 1 and a lower structure made of concrete 2 placed in the internal space H <b> 1 of the lower mold 1. 3 and the upper structure 4 composed of the upper structure 4 stacked on the lower structure 3 (lower mold 1) and the concrete 5 placed in the internal space H2 of the upper mold 4 are integrally constructed. Has been.

  In the present embodiment, as shown in FIGS. 2 to 4, the lower mold 1 is formed in a rectangular shape in plan view, and has a truss structure formed by appropriately combining vertical members such as H-shaped steel, cross members, and diagonal members. The frame main body 7 includes a side wall plate 8 that is integrally attached to each of the four side surfaces of the frame main body 7 and that forms an internal space H1 in which the concrete 2 is placed. As a result, the lower mold 1 is formed such that the inner space H1 surrounded by the side wall plate 8 is opened at the upper surface and the lower surface.

  Moreover, as shown in FIG.2 and FIG.3, the lower stage formwork 1 uses a precast concrete board as the side wall version 8, and makes the height dimension of each side wall version 8 larger than the height dimension of the frame main body 7, The lower end of each side wall plate 8 and the lower end of the frame body 7 are formed at substantially the same position in the vertical direction. Thereby, a portion (hereinafter referred to as an upper space H3) surrounded by the upper end side of the side wall plate 8 and not provided with the frame body 7 is formed on the upper end side of the lower mold 1. The side wall plate 8 is not necessarily limited to the precast concrete plate, and may be formed of other materials such as a metal plate.

  Further, as shown in FIGS. 2 to 4, the lower mold 1 is provided integrally with the cylindrical member 9 at predetermined positions on the four corners of the frame body 7 with the central axis direction being directed vertically. The support column insertion hole 10 is formed by the inner space of the cylindrical member 9. As shown in FIGS. 4 and 5, on the outer peripheral portion on the lower end side of the lower mold 1, one end side is on the lower end side of the frame body 7, and the other end side is on the lower end side of the side wall plate 8. Leakage prevention sheets (leakage prevention means) 11 that are fixedly attached and arranged annularly along the outer periphery of the lower mold 1 are provided. Further, the leakage preventing sheet 11 is attached with a slack in a portion between one side end and the other side end. That is, the leakage prevention sheet 11 is provided such that a portion between one side end and the other side end hangs downward from the lower end of the lower mold 1.

  On the other hand, in this embodiment, as shown in FIGS. 2, 3, and 6, the upper mold 4 includes a metal top plate 15, a bottom plate 16, and a side wall plate 17, and the top plate 15, bottom plate 16, It is surrounded by the side wall plate 17 and has an internal space H2 into which the concrete 5 is placed, and is formed in a box shape having a square shape in plan view. In addition, cylindrical members 18 are integrally provided at predetermined positions on the four corners side so that the central axis direction is directed upward and downward, and the top plate 15 and the bottom plate 16 are opened. A support column insertion hole 19 is formed by the inner space of the cylindrical member 18. Further, the top plate 15 is provided with a concrete placement port (not shown) for placing the concrete 5 in the internal space H2, and the placed concrete 5 is introduced into the bottom plate 1 on the bottom plate 16. For example, a concrete inlet (not shown) is formed so as to be openable and closable. Further, the upper mold frame 4 is formed in a rectangular shape slightly smaller than the lower mold frame 1 in plan view. The upper mold 4 is not necessarily made of metal, and may be formed of other materials such as precast concrete.

  Next, the construction method of the offshore structure A of the present embodiment configured as described above will be described. In this construction method, as shown in FIG. 7, first, the upper mold 4 and the lower mold 1 are manufactured at an onshore factory or production yard (form manufacturing process).

  Then, as shown in FIGS. 2, 3, and 8, the upper mold 4 is laminated on the lower mold 1. At this time, the upper mold frame 4 is formed in a square shape slightly smaller than the lower mold frame 1 in plan view, and the lower mold frame 1 is surrounded by the upper end side of the side wall plate 8 on its upper end side, 7 is formed with an upper space H3 in which 7 is not arranged. For this reason, by inserting the upper mold 4 into the upper space H3 of the lower mold 1 and installing the upper mold 4 on the frame body 7, the upper mold 4 is reliably disposed at a predetermined position on the lower mold 1. . And, since the upper mold 4 is arranged at a predetermined position on the lower mold 1 and is fixed integrally therewith, the stability is improved, so that a stable state is ensured during transportation by a later-described trolley, which is preferable. It can be transported to.

  In addition, when the upper mold 4 is arranged at a predetermined position on the lower mold 1 in this way, the cylindrical members 9 and 18 provided on the four corners of the upper mold 4 and the lower mold 1, respectively. Are overlapped in the vertical direction, and the support pillar insertion holes 10 and 19 communicate with each other in the vertical direction. Then, the support columns (legs) 20 are inserted through the pair of support column insertion holes 10 and 19 that communicate with each other in the vertical direction.

  Further, as shown in FIGS. 2, 3, 8 to 10, a first lifting jack 21 is attached to each support pillar 20, and the first lifting jack 21 is fixed to the top plate 15 of the upper mold 4. The upper mold frame 4 is attached to each support column 20 through the first lifting jack 21 so as to be lifted and lowered. A second lifting jack 22 (see FIGS. 8 to 10) is attached to the top plate 15 of the upper mold 4, and the lower mold 1 is connected to the upper mold 4 and each support column via the second lifting jack 22. 20 can be moved up and down.

  Further, as shown in FIGS. 8 to 10, in this embodiment, a strand jack is used as the second lifting jack 22. Second elevating jacks 22 are respectively installed on the four corners on the top plate 15 of the upper mold 4, and the tip side of the wire (PC steel wire) 23 of each second elevating jack 22 is the frame body of the lower mold 1. 7 is fixed. Then, the second lifting jacks 22 are driven and operated, and the wires 23 of the second lifting jacks 22 are contracted so that the upper mold 4 and the lower mold 1 are attracted to each other. They are stacked one above the other.

  Next, as shown in FIG. 3 and FIG. 11, the upper mold 4 and the lower mold 1, which are integrated by attaching a plurality of support pillars 20, a first lifting jack 21, and a second lifting jack 22, are connected to a hoist ship 25. Etc. to be loaded (loaded) on the trolley 26. At this time, in the present embodiment, a bottomed trolley 26 capable of landing the bottom 26a on the sea bottom S1 by pouring seawater into the hull is used as the trolley. In addition, the support pillars 20 are arranged on the outer side in the width direction (lateral direction) of the carriage 26 so that the integrated upper mold 4 and lower mold 1 are loaded on the carriage 26.

  Next, as shown in FIGS. 12 and 13, a plurality of support pillars 20 are attached, and the integrated upper mold 4 and lower mold 1 are transported to a predetermined position (installation point) of the construction site by the carriage 26. Moored. And in this embodiment, since the bottom type trolley 26 is used, as shown to Fig.14 (a), (b), in the stage which reached | attained the predetermined position of a construction place, the hull of the trolley 26 is used. Seawater is poured, and the bottom 26a is landed on the seabed S1.

  At this time, first, the upper mold 4 and the lower mold 1 are loaded onto the carriage 26 and transported to the construction site. It is not greatly affected by sea conditions such as. Further, since the influence of sea conditions is small, the upper mold 4 and the lower mold 1 can be transported even when the construction site is a long distance such as a remote island as compared with the conventional caisson. Furthermore, since the upper mold frame 4 and the lower mold frame 1 are laminated in a vertical direction and are fixed integrally, it can be transported in a stable state. In addition, by using a bottomed carrier 26 and landing at a predetermined position in the construction site, the carrier 26 is not shaken, and the upper mold 4 and the lower mold 1 are reliably positioned at a predetermined installation point. Retained. As a result, the upper mold 4, the lower mold 1, and the support pillar 20 are arranged at accurate positions, and construction (preparation for construction) can be performed while suppressing the influence of sea conditions such as waves. The horizontal position of the upper mold 4, the lower mold 1, and the support pillar 20 can be adjusted accurately by a horizontal jack provided on the carriage 26 so that the alignment can be performed accurately.

  Next, as shown in FIGS. 15A and 15B, the first elevating jack 21 is driven and operated, the support pillars 20 are lowered into the sea, and the lower ends 20a are settled on the seabed S1, so that a plurality of support pillars are provided. 20 is erected on the sea from the seabed S1. Further, as shown in FIGS. 16A and 16B, the first elevating jack 21 is driven to be promoted above each support column 20, and the plurality of support columns 20 are interposed via these first elevating jacks 21. The upper mold 4 and the lower mold 1 integrated with the upper mold 4 are further promoted upward via the second lifting jack 22 while being supported by the upper mold 4.

  As a result, the upper mold 4 and the lower mold 1 are separated from the carriage 26 and supported by the plurality of support pillars 20 so as to be movable up and down in a state of being arranged above the sea surface S2 (form support process). Further, in this state, the upper mold 4 and the lower mold 1 are arranged above the sea surface S2, so that external forces such as waves do not act on the upper mold 4 and the lower mold 1 (action). Thus, the upper mold 4 and the lower mold 1 are disposed in a stable state.

  In addition, when the upper mold 4 and the lower mold 1 are supported by a plurality of support pillars 20 and arranged above the sea surface S2, the upper molds are mainly against external forces such as waves acting on the support pillars 20. 4, the lower mold 1, and the supporting column 20 are resisted by their own weight (gravity). For this reason, in this embodiment, as shown to Fig.17 (a), (b), seawater is used for the interior space H2 of the upper stage form 4 of the state arrange | positioned above the sea level S2 using the pumping / draining apparatus 27. Pump up and pour water. Thereby, the resistance to external force increases by the weight of the injected seawater, and the upper mold 4 and the lower mold 1 supported by the plurality of support pillars 20 are arranged in a more stable state. Become.

  Next, seawater is discharged from the hull to release the bottoming state, and the trolley 26 is moved to the outside of the installation point through the space between the support pillars 20 from directly below the upper mold 4 and the lower mold 1. Then, as shown in FIG. 18, the second lifting jack 22 is driven to operate, the wire 23 is extended, and the lower mold 1 is lowered to the seabed S <b> 1 while being suspended and supported by the upper mold 4. As shown in FIG. 19, the concrete 2 is placed from the concrete plant ship 28 into the internal space H <b> 1 of the lower mold 1 at the stage where the lower mold 1 is installed at a predetermined position on the seabed S <b> 1.

  At this time, as shown in FIG. 5, the concrete 2 is placed on the leakage prevention sheet 11 disposed in an annular shape along the outer periphery of the lower mold 1 in advance. When the concrete 2 is placed on the leakage prevention sheet 11 in this way, the leakage prevention sheet 11 is attached with a slack in a portion between one side end and the other side end, so that it is pressed with the weight of the concrete 2 And adheres to the unevenness of the sea bottom S1. Thereby, the leak prevention sheet 11 interrupts | blocks between the internal space H1 and the exterior of the lower mold 1. For this reason, when the concrete 2 is placed in the internal space H1 of the lower mold 1 so that the frame body 7 is buried, the concrete 2 does not leak out of the lower mold 1 by the leakage prevention sheet 11, The concrete 2 is reliably filled into the internal space H1 of the lower mold 1.

  Further, as shown in FIGS. 1, 4 and 5, the lower mold 1 is provided with a frame body 7 having a truss structure and a plate-like side wall plate 8, and the upper end side and the lower end side are opened. . For this reason, the concrete 2 laid in the internal space H1 of the lower mold 1 is laid on the sea floor S1 from the opening on the lower end side. By placing concrete 2 on the bottom surface S1 in this way, it is unnecessary to level the bottom surface S1 flatly, that is, it is not necessary to provide a water bottom foundation such as a rubble mound as in the past, The lower structure 3 composed of the lower mold 1 and the concrete 2 placed thereon can be constructed (lower structure forming step). In addition, since the lower end side of the lower mold 1 is open, no lifting pressure is generated, so that the lower structure 3 can be constructed in a stable state.

  At this time, the upper mold 4 is left, the lower mold 1 is lowered, the concrete 2 is cast, and the lower structure 3 is formed in advance by dividing the marine structure A to be constructed. Thus, the area of the lower mold 1 that receives external forces such as waves is smaller than that of the conventional caisson. Also from this point, when the lower mold 1 is set (when the lower structure 3 is constructed), the influence of sea conditions such as waves can be reduced.

  Furthermore, in this embodiment, since the lower mold 1 is provided with the truss structure frame body 7 and has excellent strength characteristics, even if an external force such as a wave acts on the lower mold 1, an external force is transmitted through the frame body 7. Is reliably transmitted to the plurality of support pillars 20 to ensure a stable state. Even when the lower mold 1 is configured by disposing the frame body 7 that enhances the strength characteristics in the internal space H1 surrounded by the side wall plate 8, the frame body 7 has a truss structure. The concrete 2 is densely filled into the internal space H1 of the lower mold 1 without hindering the fluidity and filling properties of the concrete 2 provided.

  Next, as shown in FIG. 20, the first lifting / lowering jack 21 is driven to lower the upper mold 4 and set on the lower mold 1. Thereafter, the support pillar 20, the first lifting jack 21, the second lifting jack 22, etc. are removed. Then, as shown in FIG. 21, using a concrete plant ship 28 or the like, the concrete 5 is placed and filled into the internal space H2 of the upper mold 4 from the concrete placement opening formed in the top plate 15, and the upper structure 6 is filled. (Upper structure forming step). At this time, in the present embodiment, the placed concrete 5 is integrated with the concrete 2 of the lower structure 3 through the concrete inlet formed in the bottom plate 16 of the upper mold 4. Then, when the placed concrete 5 (2) is hardened, the offshore structure A in which the upper structure 3 and the lower structure 6 are integrated is constructed, and the construction is completed.

  Therefore, in the construction method of the marine structure A and the marine structure A of the present embodiment, the upper mold frame 4 and the lower mold frame 1 are manufactured at an onshore factory or production yard, and the plurality of support columns 20 are moved up and down. It can be placed on the trolley 26 in a state of being attached to the upper and lower molds 4 and 1 placed in a stacked manner and transported to the construction site. Then, at the construction site, with the upper column 4 and the lower frame 1 attached, the support column 20 is lowered into the sea so that the lower end 20a is settled on the seabed S1, and the plurality of support columns thus erected 20, the upper mold 4 and the lower mold 1 can be supported in a state of being arranged above the sea surface S2.

  Thereby, while the upper mold frame 4 and the lower mold frame 1 manufactured in the mold manufacturing process are transported to the construction site, it is possible to suppress the influence of sea conditions such as waves. In the mold support step, the upper mold 4 and the lower mold 1 are supported by the plurality of support pillars 20 at a predetermined position of the construction site and above the sea surface S2, before being set. The upper mold 4 and the lower mold 1 can be arranged at predetermined positions by suppressing the action of external forces such as waves on the upper mold 4 and the lower mold 1 and reducing the influence of sea conditions.

  In the lower structure forming step, when the lower mold 1 is lowered to the seabed S1 and the concrete 2 is placed in the inner space H1, the bottom (lower surface) is opened to form the lower mold 1. Thus, the concrete 2 can be placed on the sea bottom S1, and the bottom structure 3 can be formed without leveling the sea bottom S1 flat (without providing a water bottom foundation such as a rubble mound as in the past). it can. At this time, the upper mold 4 is left, the lower mold 1 is lowered, the concrete 2 is cast, and the lower structure 3 is formed in advance by dividing the marine structure A to be constructed. Since the area of the lower mold 1 that receives external forces such as waves is smaller than that of the conventional caisson, the influence of sea conditions such as waves when the lower mold 1 is set (when the lower structure 3 is constructed). Can be kept small.

  Further, in the upper structure forming step, the upper mold 4 is lowered and stacked on the lower structure 3, and the concrete 5 is placed in the internal space H 2 of the upper mold 4 to be integrated with the lower structure 3. It is possible to form the superstructure 6 and thus the marine structure A. At this time, by constructing the upper structure 6 in the form of dividing the offshore structure A to be constructed after the lower structure 3, the area of the upper mold 4 receiving external force such as waves is smaller than that of the conventional caisson. Therefore, even when the upper mold 4 is set (when the upper structure 6 is constructed), it is possible to reduce the influence of sea conditions such as waves.

  Therefore, according to the construction method of the marine structure A and the marine structure A of the present embodiment, the upper structure 6 in the form in which the marine structure A to be constructed is divided using the upper mold 4 and the lower mold 1. By constructing the substructure 3 in order, the influence of sea conditions such as waves can be kept small, and even in remote areas such as remote islands, marine structures A such as breakwaters, quay walls and revetments can be efficiently Construction can be done in a short period of time.

  Moreover, in the construction method of the marine structure A and the marine structure A according to the present embodiment, the upper formwork 4 and the lower formwork 1 are transported to the construction site by the bottomed carrier 26, and the bottomed carrier 26. The upper mold 4 and the lower mold 1 can be positioned and held at predetermined positions at the construction site by injecting seawater into the hull and landing the bottom 26a on the seabed S1. Then, the support column 20 is lowered into the sea, the lower end 20a is settled on the seabed S1, and the upper mold frame 4 and the lower mold frame 1 are supported by the plurality of standing support columns 20 so as to be movable up and down. In addition, it is possible to dispose the upper mold 4 and the lower mold 1 in a state where they are arranged at predetermined positions in the construction site and above the sea surface S2.

  Furthermore, by pumping seawater into the internal space H2 of the upper mold 4 in a state of being arranged above the sea level S2, the resistance to external force can be increased by the weight of the poured seawater, A more stable state can be achieved.

  Further, since the lower mold 1 is provided with the truss-structured frame body 7, it is possible to form the lower mold 1 having excellent strength characteristics, and when an external force such as a wave acts on the lower mold 1 In addition, an external force can be transmitted to and received by the plurality of support pillars 20 through the frame body 7. Thereby, it becomes possible to perform construction in a more stable state.

  Further, even when the frame main body 7 that enhances the strength characteristics is disposed in the internal space H1 surrounded by the side wall plate 8 to constitute the lower mold 1, the frame main body 7 has a truss structure, so When the concrete 2 is placed in the internal space H1 of the mold 1, the fluidity and filling property of the concrete 2 are not hindered, and the internal space H1 can be filled with the concrete 2 suitably (closely). Become.

  Further, the leak prevention sheet 11 provided on the outer peripheral side of the lower mold 1 is pressed against the concrete 2 placed in the inner space H1 of the lower mold 1 so that the sea floor S1 is flattened. Without smoothing, the internal space H1 of the lower mold 1 can be shut off from the outside with the leakage prevention sheet 11 interposed therebetween. As a result, the concrete 2 placed in the internal space H1 of the lower mold 1 can be prevented from leaking to the outside, and the lower structure 3 and thus the offshore structure A1 can be suitably constructed.

  As mentioned above, although the construction method of the offshore structure and the embodiment of the offshore structure according to the present invention have been described, the present invention is not limited to the above embodiment, and can be appropriately changed without departing from the gist thereof. It is.

  For example, it is possible to form the lower mold 1 (the shape of the lower end of the lower mold 1) in accordance with the inclination of the sea bottom S1.

  Moreover, in this embodiment, although it demonstrated as what was constructed without providing underwater foundations, such as a rubble mound, on the seabed S1, after constructing an underwater foundation on the seabed S1, and flattening the seabed S1, You may make it apply this invention.

  Further, in the present embodiment, a plurality of support pillars 20 are attached and the integrated upper mold frame 4 and lower mold frame 1 are transported to a predetermined position (installation point) at a construction site using a bottomed carrier 26. As explained. On the other hand, a plurality of support pillars 20 may be attached, and the integrated upper mold 4 and lower mold 1 may be transported to a construction site using a semi-submersible trolley 29.

  In this case, as shown in FIG. 22, seawater is supplied to the hull of the semi-submersible trolley 29 when the upper mold 4 and the lower mold 1 are transported to the construction site by the semi-submersible trolley 29. Water is poured, and the semi-submersible trolley 29 is submerged until the upper mold 4 and the lower mold 1 float on the sea surface S2. Next, as shown in FIG. 23, the raised upper mold 4 and lower mold 1 are towed to a predetermined position of the construction site by dredger, and the support pillar is lowered into the sea as shown in FIG. The upper mold frame and the lower mold frame are supported so as to be movable up and down by a plurality of standing support columns. Further, as shown in FIG. 25, the upper and lower molds are moved up and down from the sea surface. As a result, it is possible to reliably and easily dispose the upper and lower molds at predetermined positions (installation points) at the construction site and above the sea level. Moreover, after raising and lowering the upper and lower molds upward from the sea surface in this way, an offshore structure can be constructed by performing the same operation as the present embodiment shown in FIGS. it can. Therefore, in this case as well, it is possible to obtain the same operational effects as in this embodiment.

DESCRIPTION OF SYMBOLS 1 Lower mold 2 Concrete 3 Lower structure 4 Upper mold 5 Concrete 6 Upper structure 7 Frame main body 8 Side wall plate 9 Cylindrical member 10 Support pillar insertion hole 11 Leak prevention sheet (leak prevention means)
15 Top plate 16 Bottom plate 17 Side wall plate 18 Cylindrical member 19 Support column insertion hole 20 Support column (leg)
21 First lifting jack 22 Second lifting jack 23 Wire 25 Hoist ship 26 Base ship (bottomed type base ship)
26a Ship bottom 27 Pumping / draining device 28 Concrete plant ship 29 Carrier (semi-submersible carrier)
A Ocean structure H1 Internal space H2 Internal space H3 Upper space S1 Sea bottom (sea floor)
S2 sea level

Claims (7)

A mold production process for producing an upper mold frame and a lower mold frame that are arranged in a vertical stack with an internal space surrounded by at least a side wall version;
A plurality of support pillars standing at the bottom of the seabed, and a support process for supporting the upper mold form and the lower mold form so as to be movable up and down in a state of being arranged above the sea surface;
A lower structure forming step in which the lower mold is lowered to the sea floor, and concrete is placed in an internal space of the lower mold to form a lower structure;
An upper structure forming step in which the upper mold is lowered and placed on the lower structure, and concrete is placed in the internal space of the upper mold to form an upper structure integrated with the lower structure. The construction method of the offshore structure characterized by comprising. In the construction method of the offshore structure of Claim 1,
The marine structure construction method, wherein the lower mold is formed by attaching the side wall plate to a truss structure frame body. In the construction method of the offshore structure according to claim 1 or claim 2,
A method for constructing an offshore structure, characterized in that concrete is placed in the inner space on the outer peripheral side of the lower mold form, and leakage preventing means that is pressed against the concrete and closely contacts the seabed is provided. . In the construction method of the offshore structure as described in any one of Claims 1-3,
The upper mold is formed with an internal space surrounded by at least the side wall plate and the bottom plate,
A construction method for an offshore structure, wherein seawater is pumped and poured into an internal space of the upper formwork arranged above the sea surface and supported by the support pillar. In the construction method of the offshore structure as described in any one of Claims 1-4,
A method for constructing an offshore structure characterized in that the upper mold frame and the lower mold frame are transported to a construction site using a bottomed trolley in a state where the plurality of support pillars are attached while being laminated in a vertical direction . In the construction method of the offshore structure as described in any one of Claims 1-4,
A method for constructing an offshore structure characterized in that the upper formwork and the lower formwork are transported to a construction site using a semi-submersible trolley in a state where the plurality of support pillars are attached while being laminated in a vertical direction .   An offshore structure constructed using the offshore structure construction method according to claim 1.

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