JP4018288B2 - Artificial ground made of box that can pass water and its construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a large-scale artificial ground that is installed on the surface of relatively shallow water in soft ground such as the sea, rivers, lakes and the like, and its construction method, and particularly enables rapid construction and adverse effects on the environment of surrounding water areas. It is related to artificial ground that has been made to have no
[0002]
[Prior art]
In recent years, various large-scale artificial ground concepts have been proposed in response to the needs for effective use of marine space. In the past, artificial ground was constructed by building deadlines and then dumping waste and earth and sand, but recently, artificial ground using large-scale floating bodies (mega floats) has been proposed, and floating airports and various industries have been proposed. The use for facilities and leisure facilities has been proposed and has become a hot topic. This floating-type artificial ground is constructed by floating a large number of box-type units made in yards and docks and joining them offshore, and mooring the larger ones on the sea floor with pontoons and mooring lines.
[0003]
In addition, there is a “artificial ground construction method” disclosed in Japanese Patent Laid-Open No. 8-232251 as a prior art approximated to the present invention. In this artificial ground, as shown in FIG. 13, a vertical wall 24 rising to the center position of the horizontal base portion 23 is formed in an inverted T shape, and has a hollow air chamber 25 inside the housing, and an air vent plug (not shown). 1) is manufactured on land. After leveling the seabed ground at the construction site of the artificial ground, the inverted T-shaped unit 21 is towed to the construction site, adjacent vertical wall portions 24 are arranged orthogonally, air plugs are opened, and the base portion 23 is grounded. Land on. The floor slab 22 is formed on the sea surface above the vertical wall portion 24.
[0004]
[Problems to be solved by the invention]
Among the conventional technologies, the landfill method has a long construction period, impacts on the environment due to the collection and transportation of landfill sand, land subsidence after landfill, and adverse effects on the surrounding waters ecosystem due to landfill There is a problem.
[0005]
In addition, in the case of the floating body method, the level of the upper surface of the artificial ground changes following the fluctuation of the sea surface due to tide changes, etc., and when applying to shallow water depths, the bottom surface of the box-shaped floating body approaches the bottom of the water, There is concern about the negative impact on the ecosystem of the surrounding water area by blocking the flow of water. Moreover, this floating body type is said to be economical at deep water depths, and there are problems such as economical disadvantages when applied to shallow water depths.
[0006]
On the other hand, the “artificial ground” (shown in FIG. 13) disclosed in Japanese Patent Laid-Open No. 8-232251 floats the inverted T-shaped unit 21 manufactured on land to the construction point of the artificial ground, opens the air plug, and increases the buoyancy. Since the base portion 23 is landed and installed on the submarine ground, the local construction period can be shortened. Further, the inverted T-shaped unit 21 installed on the seabed ground has good stability. Further, the adjacent vertical wall portions 24 are arranged orthogonally, and the floor slab 22 is formed on the sea surface above the vertical wall portions 24. Therefore, it is described that the marine ecosystem is preserved because the flow of water under the artificial ground is not hindered.
[0007]
However, since this artificial ground is supported by landing the base portion 23 on the seabed ground, sufficient supporting force cannot be obtained on the soft ground, and uneven subsidence is likely to occur, and a large ground improvement is required. Easy to move horizontally when subjected to horizontal external forces such as earthquakes.
Further, the upper floor slab 22 provided on the inverted T-shaped unit 21 is difficult to join, and the work period is not shortened because it is a field work.
Furthermore, since the water flow under the artificial ground passes through the gap between the adjacent perpendicular wall portions 24 arranged orthogonally, the water flow is refracted and a smooth flow cannot be obtained.
[0008]
The artificial ground of the present invention solves the above-mentioned problems, reliably supports the artificial ground even at the bottom of soft ground, and smoothes the flow of water under the artificial ground so as not to adversely affect the environment and ecosystem of the surrounding water area. The purpose is to provide a construction method that can further shorten the construction period of local construction.
[0009]
[Means for solving the problems]
The artificial ground of the present invention that achieves the above object is summarized as follows.
If it demonstrates with reference to the example shown below from FIG. 1, in the artificial ground 1 of this invention, it is comprised by the bottom plate 5 which has the space 11 in which buoyancy adjustment is possible, the upper plate 3 located on the side plate 4 and the water surface, A box unit 2 having a plurality of through holes 8 into which the piles 7 can be inserted is formed in the bottom plate 5 and the upper plate 3 and a space 6 through which the water can flow is formed on the leveled water bottom ground 10. A plurality of adjacent box units 2 are joined to each other. The box unit 2 is connected to and supported by a plurality of piles 7 penetrating into the water bottom ground, or the bottom of the box unit 2 with the horizontal resistance plate 9 protruding below the bottom plate 5 is leveled. You may make it make it softly settle on the ground 10.
[0010]
Further, the bottom plate 5 and the side plate 4 in the box unit 2 are manufactured by fixing a steel plate stiffener 13 to a steel plate outer shell material 12, and filling concrete 15 in all or part of the internal space. You may make it fill. Further, when the bottom plate 5, the side plate 4 and the upper plate 3 are made of a steel plate outer shell material 12, a corrosion-resistant metal thin plate is lined on the submerged portion, the tidal portion and the splash portion of the box unit surface 2. Anticorrosion.
[0011]
Moreover, about the construction method of the artificial ground of this invention, as shown to FIG. 10 (a), (b), FIG. 11 (a), (b), FIG. 12 (a), (b), the following ( 1) to (7). That means
(1) A box unit 2 comprising a bottom plate 5 having a space capable of adjusting buoyancy, a side plate 4 and an upper plate 3 positioned on the surface of the water, and having a space 6 capable of passing water inside, is obtained by a land yard or dock. To manufacture.
(2) Excavate and level the water bottom ground at the box unit installation location to a predetermined depth. (Fig. 10, a)
(3) The box unit 2 manufactured in the land yard or dock is levitated and towed to the installation site. (Fig. 10, b)
(4) Water is poured into the buoyancy adjustment space 11 of one or both of the bottom plate 5 and the side plate 4 to reduce the buoyancy, and the box unit 2 is set on the leveled water bottom ground 10. (Fig. 11, a)
(5) The pile 7 is inserted into the through-hole 8 of the box unit 2 from above and penetrated into the water bottom ground 10, and the pile head is coupled to the box unit with the bonding material 16. (Fig. 11, b, Fig. 12, a)
Alternatively, the horizontal resistance plate 9 is projected below the bottom plate of the box unit. In this case, in the step of pouring water into the buoyancy adjustment space 11 described above and reducing the buoyancy, the buoyancy is left so as not to increase the weight of the box, and the load is applied to the water bottom ground 10 by making it softly settle.
(6) After the second box unit 2 is disposed adjacent to the existing box unit, the level is adjusted and the box unit 2 is bonded by the bonding material 17. (12, b)
(7) After the box unit 2 is installed on the bottom of the water, concrete 15 is filled into the bottom slab 5 and the side plate 4 of the box unit 2 and filled with concrete 15 inside.
It is a construction method for artificial ground made of a water-permeable box, which is constructed by the above-described process.
[0012]
[Action]
The artificial ground 1 of the present invention has a great feature in that it is a space 6 through which water can flow inside the box unit 2. In other words, having this water-permeable space 6 does not impede water flow such as river water at the estuary and tides at the shore and cause changes in the surrounding flow conditions. It does not disturb the growth environment of aquatic organisms such as shellfish and shellfish. Further, since the water flow acting on the box unit 2 is received only by the side plate 4, the pressure receiving area received from the water flow is small, and the design external force can be reduced.
[0013]
Further, the buoyancy adjustment space 11 of the box unit 2 gives buoyancy when the box unit 2 manufactured on the land yard or dock is levitated and towed, and after being submerged in the water bottom ground 10, the box unit 2 is softly settled. The load applied to the water bottom ground 10 that supports the body unit 2 is reduced. Moreover, in the case where the box unit 2 is supported by a pile, the vertical load on the pile 7 can be reduced.
[0014]
Since the box unit 2 is towed with the upper plate 3 positioned above the water surface, buoyancy can be used only in the submerged portions of the bottom plate 5 and the lower side plate 4. For this reason, the stiffener 13 is fixed to the outer shell 12 made of a steel plate so that the bottom plate 5 and the side plate 4 can easily obtain larger buoyancy. It is preferable that the space 11 is formed and the rigidity is secured. In this case, after the box unit 2 is sunk in the water bottom ground 10, it is better to fill all or a part of the internal space with the intermediate packed concrete 15 to ensure further rigidity.
The outer shell 12 made of steel plate acts as a permanent mold during the filling operation of the concrete 15 that is filled in the middle.
[0015]
When the bottom plate 5 and the side plate 4 are made of steel plate outer shell material 12, it is better to line a corrosion-resistant metal sheet on the submerged portion, tidal portion, and splashing portion of the surface of the box unit 2 in order to prevent corrosion prevention. Good.
[0016]
Further, in the artificial ground construction method of the present invention, the box unit 2 is manufactured in a near-finished state at the land yard or dock, and after towing to the installation site, the water bottom ground 10 that has been leveled in advance is prepared. After installation, the pile 7 is inserted into the through hole 8 of the box unit 2 and the pile 7 is inserted into the bottom bottom ground 10 to be coupled, or the horizontal resistance plate 9 is projected to construct the construction. In addition, the local construction period can be shortened.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment for constructing an artificial ground according to the present invention will be described with reference to the drawings.
FIG. 1 is a partial perspective view of an embodiment of an artificial ground 1 that supports a box unit 2 that allows water to pass through inside the present invention. The artificial ground 1 is implemented as an artificial ground installed in the estuary 19 as shown in a perspective view in FIG. 8, or as an artificial ground installed in the coastal area 20 as shown in a plan view in FIG. Is done.
And if an artificial ground is constructed in the above-mentioned location with a conventional landfill system or a box that does not have a water flow space, the river width will be narrowed, causing flooding or changing the flow during heavy rain, and the flow of the tidal current May change and disturb the growth environment of seafood due to scouring and sedimentation in the riverbed and surrounding coastal areas, but the present invention does not have such an adverse effect on the environment.
[0018]
This will be further described with reference to FIG. The artificial ground 1 of the present invention is supported by a steel pipe pile 7 in which a frame constituted by joining a plurality of box units 2 is installed on a water bottom ground 10 and penetrates into a support layer below the water bottom ground 10. The box unit 2 forming the frame is composed of an upper plate 3, a side plate 4 and a bottom plate 5 to be an artificial ground surface 1, and the side plate 4 is opened to be a space 6 through which water can pass inside the box unit. Yes. The water flow space 6 may be provided in the direction of the water flow 19 such as river water or tidal current. However, when the water flow 19 does not move or cannot be determined, it is preferable to allow water to pass in the orthogonal direction as illustrated.
[0019]
FIG. 2 is a perspective view of the box unit 2. The box unit 2 is manufactured in a land yard or dock, levitated to the site, and then sunk. For this reason, the bottom plate 5 has a buoyancy adjustment space 11 having a pouring / draining valve 14 as shown in FIG. When the buoyancy is insufficient only with the bottom plate 5, the buoyancy adjustment space 11 is also provided at the lower portion of the side plate 4 as shown in FIG. 7.
[0020]
This buoyancy adjusting space 11 is filled with concrete 15 after leaving the box unit 2 on the bottom of the water at the site and leaving a portion that retains appropriate buoyancy. (See Figure 5)
The entire box unit 2 may have a reinforced concrete structure, a composite structure of steel frame or steel plate and concrete, but an upper plate 3 shown in FIG. 4 (a), a bottom plate 5 shown in FIG. 4 (b), and a side plate 4 shown in FIG. If the steel plate outer shell 12 is welded with the steel plate stiffener 13, the weight of the box unit 2 relative to the rigidity can be reduced compared to concrete, and the buoyancy adjustment space 11 of the bottom plate 5 can be increased. I can take it. Note that all or part of the buoyancy adjustment space 11 in the outer shell material 12 made of steel shell is filled with filled concrete 15 on site after the box unit is installed.
[0021]
As shown in FIG. 2, the box unit 2 has a through-hole 8 through which the steel pipe pile 7 can be inserted into the upper plate 3 and the bottom plate 5 from the upper plate 3 through the bottom plate 5 in the vicinity of the side plate 4. Are provided. The steel pipe pile 7 is inserted into the underwater ground 10 through the upper and lower through holes 8 after the box unit 2 is installed on the underwater ground 10. In addition, between the through-hole 8 and the steel pipe pile 7, it joins so that it may become watertight with respect to the space 11 for buoyancy adjustment of the box unit 2, and water does not flow in into the said space 11 from this penetration part. .
The steel pipe pile 7 inserted in each through-hole 8 of the upper plate 3 and the bottom plate 5 is cut at a position passing through the through-hole 8 of the bottom plate 5, and the head of the cut steel pipe pile 7 is shown in FIG. Thus, it is firmly coupled to the bottom plate 5 of the box unit 2. Although a detailed description of this connection is omitted, known means such as welding via the connecting members 16 and 16a, concrete 15 with studs and shear keys interposed, and grout may be used. The through hole 8 on the bottom plate upper surface is closed with a lid 26. In addition, the upper part of the steel pipe pile 7 may extend to the upper surface of the upper plate 3, and may be cut at that position and subjected to a watertight joining process. The steel pipe pile 7 may be a concrete pile.
As shown in FIGS. 6 and 7, the artificial ground 1 is configured by joining adjacent box units 2 to each other in a state where they are installed on the water bottom ground 10. Since it is difficult to position the end surfaces of adjacent box units 2 with high accuracy, it is better to use a method that can be joined even if there is some installation error. As specific joining means between the box units 2, they are joined by a joining member such as bolt joining or welding (shown schematically as the joining member 17 in the figure), or a PC steel rod / steel wire is used. . Further, the joint may be integrated by a dowel (not shown) provided in the box unit 2 and the filling concrete 15.
[0022]
Moreover, since the submerged part, the tidal part, and the splash part of the outer surface of the box unit 2 are exposed to a severe corrosive environment, it is necessary to prevent corrosion when the steel box is used. Conventional anti-corrosion coating can be applied as the anti-corrosion means, and electro-corrosion protection can be applied to the submerged part, but maintenance such as repainting for aging deterioration is required.
Therefore, it is desirable to adopt a corrosion prevention method in which a corrosion-resistant thin metal such as titanium or stainless steel that can maintain anticorrosion performance without maintenance for many years is used.
[0023]
Next, regarding the construction method of the artificial ground according to the present invention, referring to FIGS. 10 (a), (b), FIGS. 11 (a), (b), FIGS. 12 (a), (b), the following (1 ) To (8) in order.
(1) The bottom of the artificial ground installation site is shallow, and if the box unit 2 cannot be retracted, it is excavated to a predetermined depth and leveled beforehand. (Shown in Fig. 10 (a))
(2) The box unit 2 manufactured in the land yard or dock is towed to the installation site in a state where the box unit 2 is levitated with the buoyancy adjustment space 11 empty. (Shown in FIG. 10 (b))
(3) Open the exhaust valve and water injection valve 14 (shown in FIG. 4 (b)) when arriving at a predetermined installation location, inject water into the buoyancy adjustment space 11 to reduce the buoyancy and gradually sink the box unit 2. Then, land on the ground surface 10 that has been leveled. At this time, it is possible to reduce the support load of the steel pipe pile 7 by not pouring all of the buoyancy adjustment space 11 and leaving the box unit softly so as to leave a certain degree of buoyancy. (Shown in FIG. 11 (a))
(4) Next, the steel pipe pile 7 is inserted into the through hole 8 of the box unit 2 and is penetrated into the water bottom ground 10 by hammering or press-fitting. The connection extension of the steel pipe pile 7 is usually a welding method, but it is desirable to adopt a quick joint method such as screwing for quick construction. (Shown in FIG. 11 (b))
(5) When the penetration of all the steel pipe piles 7 is finished, the head part of the steel pipe pile 7 and the box unit 2 are joined by welding via a coupling member 16, a stud gibber, concrete 15 with a shear key, grout or the like. The extra length portion of the steel pipe pile 7 is cut, and a lid 26 is placed on the upper surface of the box bottom plate 5. (Shown in FIG. 12 (a))
(6) In the case of the steel box unit 2, the concrete 15 is filled in the buoyancy adjusting space 11 through the above-described pouring / draining valve.
(7) The second and subsequent box units 2 are placed on the bottom bottom ground 10 in a state of being aligned with the adjacent existing box unit 2, and then the level is adjusted. Are joined together. (Shown in FIG. 12 (b))
(8) The upper surface of the box unit 2 is finished by applying a finishing material 27 (shown in FIGS. 1 and 7) such as concrete or asphalt.
[0024]
FIG. 3 is an example of a box unit for artificial ground that does not use a pile for the box unit 2. Since the method of the present invention leaves sufficient buoyancy in the box unit 2 and softly settles on the bottom floor ground 10, it is not necessary to apply a large load to the bottom floor ground. Becomes easier to slide on the bottom of the water. As a countermeasure, in the example of FIG. 3, a horizontal resistance plate 9 is projected below the bottom plate 5 in place of the steel pipe pile 7. This horizontal resistance plate 9 is the same as the through hole 8 of the pile 7 in the box unit bottom plate 5 in advance so that it can be constructed after the box unit 2 is installed on the bottom 10 in the case of towing the shallow water. Make a hole. Then, using this hole, the bottom bottom ground 10 is excavated, and a horizontal resistance plate made of steel is installed, or a horizontal resistance plate made of reinforced concrete is provided.
[0025]
【Example】
An example of the specifications of a specific example of the artificial ground according to the present invention is as follows.
When constructing an artificial ground having a plane area of 500 m × 300 m on a soft ground having a depth of 4 m, 30 box units each having a size of 50 m × 100 m are joined.
The box unit 2 has an overall height of 11 m, and the inside is a space that allows water to flow in both directions. The box unit is provided with a steel pipe pile support or a horizontal resistance plate and is installed with a soft bottom. The upper plate level is +7 m (water surface) and the bottom plate level is -4 m (water bottom).
[0026]
【The invention's effect】
The artificial ground according to the present invention reliably supports the artificial ground even at the bottom of soft ground, and smoothes the flow of water under the artificial ground so as not to adversely affect the environment and ecosystem of the surrounding water area. It is a construction method that can shorten the construction period, and it has a great effect when applied to the following location conditions.
[0027]
(1) In the case of the waterside ground where the soil is soft and the water is relatively shallow (the coastal area).
The box unit that forms the artificial ground frame is mainly supported by the support layer under the bottom bottom ground mainly by the pile, or the bottom of the box body is supported by the bottom bottom ground in a softly settled state. Even so, no settlement occurs.
In addition, since a horizontal resistance plate is provided for a case where the box bottom plate is supported on the water bottom ground without using piles, a horizontal resistance plate is provided, so that horizontal movement does not occur against a horizontal load such as during an earthquake.
[0028]
(2) A place with running water such as an estuary or a waterfront.
Since the box unit that forms the artificial ground frame is a space that allows water to pass through inside, even if it is installed in the estuary and the river width is narrowed, it will not hinder the flowing water under the artificial ground, so it will not cause flooding. In addition, there will be no changes in the flow conditions of river water and tides in the waters around the estuary and at the water's edge, and there will be no adverse environmental impacts that would disrupt the aquatic ecosystem of seafood.
[0029]
(3) Expansion of existing facilities and structures such as airports.
Since the frame of the artificial ground is fixedly supported, the level does not change due to tidal changes and overloads unlike the floating artificial ground, and there is no step difference that fluctuates with existing facilities and structures.
(4) When the bottom plate and side plate of the box unit are made by fixing a steel plate stiffener to a steel plate outer shell material, the weight of the box unit can be reduced and large buoyancy can be easily obtained. Further, when the bottom plate and the side plate are made of steel plate outer shell material, corrosion-resistant maintenance-free can be made free by lining a corrosion-resistant metal thin plate on the submerged portion, tidal portion, and splash portion on the surface of the box unit.
[0030]
Further, in the artificial ground construction method of the present invention, the box unit is manufactured in a land yard or dock in a state close to a completed form, and is towed and installed on the site, so the construction period of the field construction can be shortened. Further, since the box units are joined to each other by landing on the leveled water bottom ground, the work can be easily and reliably performed.
[Brief description of the drawings]
FIG. 1 is a partial perspective view of an embodiment of an artificial ground according to the present invention.
FIG. 2 is a perspective view of a first example of a box unit (pile support method).
FIG. 3 is a perspective view of a second example of a box unit (soft bottom method).
FIG. 4A is a cross-sectional view of an upper plate when the box unit has a steel shell structure. (B) is a cross-sectional view of the bottom plate when the box unit has a steel shell structure.
FIG. 5 is a cross-sectional view of a coupling structure example of a bottom slab and a pile (steel pipe pile).
FIG. 6 is a connection diagram of a box unit.
7 is an enlarged cross-sectional view of part (c) of FIG.
FIG. 8 is a perspective view of an example in which the artificial ground of the present invention is installed in an estuary.
FIG. 9 is a perspective view of an example in which the artificial ground according to the present invention is installed in a coastal area.
FIGS. 10A and 10B are first and second process diagrams according to the artificial ground installation method of the present invention.
FIGS. 11A and 11B are third and fourth process diagrams according to the artificial ground installation method of the present invention. FIGS.
FIGS. 12A and 12B are fifth and sixth process diagrams according to the method for installing an artificial ground of the present invention.
FIG. 13 is a perspective view of a conventional example.
[Explanation of symbols]
1 Artificial ground 2 Box unit 3 Upper plate 4 Side plate 5 Bottom plate 6 Water flow space 7 Pile (steel pipe pile)
8 Through-hole 9 Horizontal resistance plate 10 Submarine ground 11 Buoyancy adjustment space 12 Steel plate (steel shell)
13 Stiffening material 14 Pouring / draining valve 15 Concrete 16 Connecting member 17 Joining material 18 Estuary 19 Water flow 20 Seaside 21 Reverse T unit 22 Floor slab 23 Base 24 Vertical wall 25 Air chamber 26 Lid 27 Finishing material

Claims (6)

Multiple box units composed of a bottom plate, a side plate, and a top plate located on the surface of the water that have a buoyancy-adjustable space, adjacent to the leveled water bottom ground. An artificial ground consisting of a box that allows water to flow, which is installed by connecting box units. A plurality of through-holes into which piles can be inserted into the box unit are formed, and the box unit installed on the water bottom ground is supported by being combined with a plurality of piles penetrating into the water bottom ground through the through holes. The artificial ground comprising a water-permeable box according to claim 1. 2. A water-permeable container according to claim 1, wherein a horizontal resistance plate is projected below the bottom plate of the box unit, and the box unit is softly settled on a leveled water bottom ground. Artificial ground consisting of the body. The bottom plate and the side plate of the box unit are manufactured by fixing a steel plate stiffener to a steel plate outer shell material, and a portion of the internal space is filled with filling concrete. An artificial ground comprising a water-permeable box according to any one of claims 3 to 4. 5. The artificial ground comprising a water-permeable box according to claim 4, wherein a corrosion-resistant metal thin plate is lined on a submerged part, a tidal part, and a splash part on the surface of the box unit to prevent corrosion. The following steps (1) to (7), that is,
(1) A box unit composed of a bottom plate, a side plate, and an upper plate located on the surface of the water having a buoyancy-adjustable space and having a water-permeable space inside is manufactured at an onshore yard or dock.
(2) Excavate the water bottom ground at the box unit installation location to a predetermined depth and level it.
(3) The box unit produced in the land yard or dock is levitated and towed to the installation site.
(4) A suitable amount of water is poured into the buoyancy adjustment space of either one or both of the bottom plate and the side plate to reduce the buoyancy, and the box unit is softly settled on the leveled water bottom ground.
(5) After inserting the pile into the through hole of the box unit and penetrating it into the water bottom ground, the box unit and the pile are combined, or the horizontal resistance plate is projected below the bottom plate of the box unit.
(6) After the second box unit is disposed adjacent to the existing box unit, the box units are joined to each other by adjusting the level.
(7) After the box unit is installed on the bottom of the water, concrete is filled in the bottom slab and side buoyancy adjustment spaces of the box unit and filled in.
A method for constructing artificial ground comprising a water-permeable box, which is constructed by the above process.

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