JP2020153197A - Banking method - Google Patents

Abstract

To provide a banking method capable of extending a harbor facility by making use of a large floating body structure.SOLUTION: A banking method to extend a harbor facility comprises: a process to produce riprap and crushed stone by crushing a mass formed by solidifying mortar; a process to establish an impact resistant banking by heaping the riprap on the sea bottom on a revetment side of the harbor facility; a process to establish a grounding mound by laying out the riprap on the sea bottom surface; a process to position a floating body structure at a grounding position by towing the floating body structure above the grounding mound; a process to tentatively ground the floating body structure at the grounding position by injecting sea water as ballast water into the floating body structure; a process to drain the ballast water inside the floating body structure; a process to ground the floating body structure on the grounding mound by charging an infilling mortar into the floating body structure from which the ballast water is drained; and a process to establish a banking of crushed stone on the floating body structure.SELECTED DRAWING: Figure 13

Description

The present invention relates to a method of embankment for expanding a port facility.

Described in Patent Document 1, for example, in a port adjacent to the Fukushima Daiichi Nuclear Power Station in order to temporarily store the accumulated water in the buildings of Units 5 and 6 of the Fukushima Daiichi Nuclear Power Station that occurred in the Great East Japan Earthquake. A large floating structure (hereinafter referred to as "mega float") was moored. A mega float is a box-shaped structure whose interior is separated by a watertight compartment, and is used for multiple purposes as a structure that floats on the sea by injecting ballast water into the inside. After storing the stagnant water in this mega float instead of the ballast water, the stagnant water was transferred to another storage tank. After that, the mega float is moored in the harbor with filtered water stored as ballast water inside.

Japanese Unexamined Patent Publication No. 58-047691

However, if the mega float is continuously moored in the harbor, when a tsunami occurs, it may become a drifting object and damage peripheral facilities such as harbor facilities.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a banking method capable of expanding port facilities by using a large floating structure.

The present invention is a method of embankment for expanding a port facility, in which a step of crushing a solidified mass of mortar to generate rubble and crushed stone and the rubble are piled up on the seabed on the shore protection side of the port facility. A process of creating an anti-impact embankment, a process of laying the rubble on the surface of the seabed to create a landing mound, and a process of towing a floating structure above the landing mound to position it at the landing position. A step of injecting seawater into the inside of the floating structure as ballast water to temporarily land the embankment at the landing position, a step of discharging the ballast water inside the floating structure, and the step of discharging the ballast water. It includes a step of filling the inside of the floating structure with a filling mortar and landing the floating structure on the upper part of the landing mound, and a step of forming an embankment with the crushed stone on the upper part of the floating structure. , The embankment method.

According to the present invention, a landing mound for landing a mega float on the seabed can be created with rubble artificially generated by mortar, and the floating structure is fixed to prevent the floating structure from drifting due to a tsunami. At the same time, port facilities can be expanded.

Further, the present invention includes a step of forming the crushed stone by laying the mortar on the ground and solidifying it to form a lump, and a step of crushing the solidified lump to generate the rubble. It may be configured.

According to the present invention, since rubble is generated by crushing the lump after forming a lump formed by solidifying the mortar, the strength of the rubble can be freely adjusted.

Further, in the present invention, the step of discharging the ballast water sequentially starts from the plurality of watertight compartments in a predetermined order so as to stabilize the inclination of the floating structure divided by the plurality of watertight compartments filled with ballast water. It may be configured to include the step of discharging the ballast water.

According to the present invention, the ballast water is drained from the plurality of watertight compartments in a predetermined order to the floating structure divided by the plurality of watertight compartments, so that the ballast water is drained so that the floating structure is not tilted. Can be done.

Further, in the present invention, the step of filling the filling mortar is a step of filling the watertight compartment in an empty state with the filling mortar, and a step of filling the ballast water from at least one of the watertight compartments. It may be configured to include a step of discharging according to the filling amount of the mortar.

According to the present invention, since the filling mortar is filled and the ballast water is drained in parallel, the construction period is shortened and the filling mortar, which is heavier than the ballast water, is discharged according to the amount of drainage. The structure is prevented from floating.

Further, the present invention may be configured such that the step of creating the embankment includes a step of crushing the rubble to generate crushed stone and a step of laying the crushed stone on the upper part of the floating structure. ..

According to the present invention, crushed stone can be further generated from artificially generated crushed stone, and the crushed stone can be used as a material for embankment.

According to the present invention, a port facility can be expanded by using a large floating structure.

It is a figure which shows the structure of the mega float which concerns on this invention. It is a figure which shows the mooring position, temporary position, and the landing position of a mega float. It is a figure which shows the process of moving a mega float from a temporary position to a landing position. It is a figure which shows the composition of the embankment using a mega float. It is a figure which shows the production method of the artificial ground material. It is a top view which shows the construction method of the embankment. It is sectional drawing which shows the construction method of the embankment. It is a figure which shows the order and the amount of drainage of the ballast water of a mega float. It is a figure which shows the order of draining the ballast water of a mega float and the order of filling with mortar in comparison. It is a figure which shows the order of draining the ballast water of a mega float. It is a figure which shows the state which fills the mortar in the mega float. It is a figure which shows the anticorrosion method of a mega float. It is a flowchart which shows the process flow of the embankment method using a mega float 100.

Hereinafter, the embankment method according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, the mega float 100 is a large box-shaped floating structure constructed by connecting a plurality of box-shaped structures. The Mega Float 100 includes, for example, nine boxes 1-9. Each of the boxes 1 to 9 is separated from each other by a partition wall. As a result, a plurality of watertight compartments are formed inside the Mega Float 100. Therefore, each of the boxes 1 to 9 functions as a ballast tank.

As shown in FIG. 2, the Mega Float 100 is moored in the port adjacent to the Fukushima Daiichi Nuclear Power Station, and the accumulated water in the Units 5 and 6 buildings is inside each of the boxes 1 to 9. It was temporarily stored. The moored Mega Float 100 may drift when a tsunami occurs and collide with the port facilities, destroying the port facilities. Therefore, it was planned to land the Mega Float 100 on the seabed and use it as it is as a structure for expanding port facilities.

The outline of this embankment method is to move the Mega Float 100 into the open culvert P inside the embankment T provided in the harbor and then land it on the ground.

As shown in FIGS. 3 and 4, as a first step, the mega float 100 is moved from the mooring position F1 to a temporary position F2 different from the bottoming position F3 in the open culvert P, the ballast water is drained, and the inside. Decontaminate. At this time, a landing mound M is created at the landing position in parallel. The bottoming mound M is an artificial support layer formed between the seabed and the bottom surface of the Mega Float 100. Next, as step 2, the mega float 100 is moved above the landing mound M, filled with mortar, and landed above the landing mound M. After that, embankment J is carried out on the mega float 100 to create the ground surface.

Next, the embankment method will be described in detail.

In the open culvert P including the landing position, the seabed is covered with the seafloor covering soil layer D prepared in advance. The seabed covering soil layer D is formed on the seabed made of a mudstone layer. Since the seabed is contaminated with radioactive substances after the accident, the seabed is covered with the seabed covering soil layer D to contain the radioactive substances. The seabed covering soil layer D is formed, for example, by mixing cement with a bentonite-based material to form a slurry-like mixture. The mixture is deposited to a thickness of about 70 cm on a layer of silt-based volumes deposited on the seafloor with a thickness of 10 to 20 cm.

After the mixture has solidified, a seabed covering soil layer D is created. The seabed covering soil layer D is formed in a region near the revetment with a uniaxial compressive strength of less than 20 [N / mm ² ], and in other regions with a uniaxial compressive strength of about 30 [N / mm ² ].

As shown in FIG. 5, the artificial ground material is then manufactured. As the artificial ground material, rubble B, crushed stone C, and filling mortar are produced depending on the application. The rubble B is used to create the anti-impact embankment V and the bottoming mound M, which will be described later. Crushed stone C is used as a material for embankment J for lining of Mega Float 100. The mortar is used as a filler inside the Mega Float 100.

The artificial ground material is produced by kneading fly ash made from coal ash, cement, seawater, gypsum, etc. in a predetermined mixing ratio. Artificial ground materials are manufactured by changing the compounding ratio and additives according to the application.

Fly ash is produced, for example, from coal ash emitted from coal-fired power plants. The fly ash used for the artificial ground material may be produced by any coal type. It was also confirmed that by adding seawater to fly ash and cement and kneading them, the strength of the produced material was improved as compared with the case of kneading fresh water.

In the manufacturing process of the artificial ground material for the rubble B and the crushed stone C, first, the material is kneaded in the kneading plant Q, and then the material is spread in a plate shape on the ground and compacted. Then, the compacted material is cured and solidified to form a plate-shaped mass H. The generated mass H is first crushed to a particle size of about 50 [cm] by a heavy machine such as a backhoe G to produce rubble B. The rubble B is divided into a material used as it is and a material used as crushed stone C. The rubble B, which is the material of the crushed stone C, is further crushed by a heavy machine to a particle size of about 4 [cm]. As a result, crushed stone C is produced.

For the rubble B for the bottoming mound M, for example, the mixing ratio of the materials is adjusted so that the uniaxial compression strength is 10 [N / mm ² ]. The amount of fly ash used is 1000 [kg / m ³ ]. The amount of cement is adjusted, for example, from 100 [kg / m ³ ] to 200 [kg / m ³ ].

Further, the number of times the rubble B is crushed from the lump H is adjusted so that the internal friction angle is 35 degrees or more. It is empirically known that the internal friction angle becomes smaller as the number of times of crushing increases and the size of the generated stone becomes finer. Therefore, the lump H is adjusted so that the size of the rubble B becomes about 50 [cm]. Is crushed.

The rubble B is formed by forming a bottoming mound M with the rubble B on the seabed covering soil layer D on the seabed, and when the megafloat 100 is landed on the bottoming mound M, the seabed covering soil is subjected to the load of the megafloat 100. The rubble B is set to be destroyed so as not to destroy the layer D.

The crushed stone B is further crushed to generate crushed stone C having a particle size of about 4 cm. Since crushed stone C is produced by crushing rubble stone B, the uniaxial compressive strength, unit volume weight, and amount of fly ash used are the same as those of crushed stone B, but the internal friction angle is 30 depending on the size of the crushed particle size. It is adjusted to be more than the degree.

The strength and internal friction angle of the rubble B may be adjusted according to the area to be constructed. For example, the rubble B to be constructed on the revetment portion may be manufactured by increasing the amount of cement so that the uniaxial compressive strength is 30 [N / mm ² ] and the internal friction angle is 40 degrees. Further, the mixing ratio of the material of the rubble B is adjusted so that the unit volume weight is 13 [kN / m ³ ], which is smaller than the unit volume weight of the natural stone. In addition, cement, which is a material for artificial ground materials, is adjusted to a mixing ratio of the degree of ground improvement.

Among the artificial ground materials, the filling mortar is used as a filling material to be filled inside the Mega Float 100 as described later. The filling mortar is a filling mortar in which the blending ratio of fly ash is changed. The weight of the filling mortar is adjusted to ensure that the Mega Float 100 bottoms out. The uniaxial compressive strength of the filling mortar after curing is adjusted to be 10 [N / mm ² ] or more, which is the same as that of waste stone, and the unit volume weight is 18.5 [kN / m ³ ]. The amount of fly ash used is 700 [kg / m ³ ] or more.

Copper slag is mixed in the filling mortar, and the unit volume weight is adjusted to 18.5 [kN / m ³ ]. Sand is further mixed into the filling mortar, and the slump is adjusted to be as soft as 18 cm ± 2.5 cm in order to increase the fluidity when the filling mortar is filled in the mega float 100.

Next, a barrier embankment V is constructed on the sea-side impermeable wall.

As shown in FIGS. 6 and 7, when the megafloat 100 is moved or moored, the megafloat 100 moves to the sea side impermeable wall W side due to a natural phenomenon, and the megafloat 100 It is created so that the sea side impermeable wall W is not damaged even if the sea side impermeable wall W comes into direct contact with the sea side impermeable wall W. In the construction of the anti-impact embankment V, first, the steel pipe sheet pile surface of the sea-side impermeable wall W is covered with a cushioning sheet E formed of an elastic body to protect it while confirming it by diving work. The anti-impact embankment V is created by raising the rubble B generated in advance to the surface of the sea. The anti-impact embankment V is created by throwing the rubble B into the sea on the club ship U, repeating the process of leveling the rubble B using the backhoe G, and sequentially raising the rubble B. The slope K of the anti-impact embankment V is formed with a gradient such that the height becomes lower toward the sea side when viewed in cross section.

Next, the Mega Float 100 is moved into the open culvert P.

The Mega Float 100 moored outside the open dock P in the port is towed from the mooring position F1 outside the open dock P and temporarily moored at a temporary position F2 in the open dock P different from the landing position F3 ( See FIGS. 2 and 3). The Mega Float 100 is towed, for example, using a plurality of winches and mooring lines installed on the ground or on an embankment.

At the temporary position F2, the ballast water inside the Mega Float 100 is drained and decontaminated. The stagnant water stored inside the Mega Float 100 is discharged, and the stagnant water is transferred to the storage tank on the ground side. The inside of the Mega Float 100 is decontaminated by hydraulic cleaning. The decontamination work mainly removes sludge adhering to the inside of the Mega Float 100. The water used for hydraulic cleaning is stored in a temporary pool and collected, passed through a filter to collect sludge, and used again for hydraulic cleaning. After dehydration, the filter that collects sludge is stored in a temporary storage area. The hydraulic wash water is treated using a desalination device.

In parallel with the discharge treatment of ballast water, a bottoming mound M is created at the landing position of the mega float 100. The bottoming mound M is created by throwing a pre-manufactured rubble B into the sea on a club ship U. The bottoming mound M is adjusted to a height that ensures that the upper part of the megafloat 100 comes out of the sea surface when the megafloat 100 bottoms out. The landing mound M is adjusted to, for example, a height at which the height from the sea surface is secured at 0.7 [m] or more at high tide. The bottom mound M has a slope formed with a slope such that the end portion on the underwater side is cross-sectionally viewed and the height becomes lower toward the sea side.

After the landing mound M is created, the mega float 100 from which the ballast water is discharged is towed to the landing position on the landing mound M. The Mega Float 100 is positioned by GPS surveying with respect to the landing position. When the Mega Float 100 stops on the landing position on the landing mound M, seawater is injected into the inside as ballast water.

As shown in FIG. 8, water is not injected into all the boxes 1 to 9 of the Mega Float 100, but is not injected into, for example, the boxes 1 and 2. At this time, the other boxes 3 to 9 are injected with a weight of water that ensures a stable weight so that the mega float 100 does not resurface. Then, the mega float 100 settles as the ballast water increases, and the bottom surface of the mega float 100 lands above the landing mound M. Therefore, the Mega Float 100 is in a state of being filled with ballast water and temporarily landed.

The bottoming process of the mega float 100 is performed in a state where the mega float 100 is temporarily landed.

As shown in FIGS. 9 to 11, in the mega float 100, at least one empty box is filled with the filling mortar, and at the same time, the ballast water is discharged from the ballast water-filled box. It is drained. The drainage of the ballast water of the Mega Float 100 and the filling of the filling mortar are carried out while maintaining a state of not less than 12500 [t] so as to secure a stable weight so that the Mega Float 100 does not resurface.

At this time, ballast water is sequentially discharged from at least one watertight compartment composed of a plurality of boxes in a predetermined order so as to stabilize the tilt of the megafloat 100 so that the megafloat 100 does not tilt in one direction. At the same time, at least one empty watertight compartment is filled with a filling mortar in an amount corresponding to the amount of ballast water discharged from at least one watertight compartment. The filling mortar is filled, for example, with a filling amount of 300 [m ³ / day].

Specifically, first, the filling mortar is filled from the empty box 1, and at the same time, drainage is performed from the box 1 and the box 3 at a substantially target position. Next, the empty box 2 is filled with the filling mortar, and at the same time, drainage is performed from the box 2 and the box 4 at a substantially target position. Next, the mortar for filling is filled in the drained and emptied boxes 3 and 4, and at the same time, the drainage is performed from the boxes 3 and 4 and the boxes 5 at substantially target positions. Next, the mortar for filling is filled into the empty box 5 that has been drained, and at the same time, drainage is performed from the box 5 and the box 6 at a substantially target position.

Next, the mortar for filling is filled into the empty box 6 that has been drained, and at the same time, drainage is performed from the box 6 and the box 7 at a substantially target position. Next, the mortar for filling is filled into the empty box 7 that has been drained, and at the same time, drainage is performed from the box 7 and the box 8 at a substantially target position. Next, the mortar for filling is filled into the empty box 8 that has been drained, and at the same time, drainage is performed from the box 8 and the box 9 at a substantially target position. Next, the filled box 9 that has been drained and emptied is filled with the filling mortar, and the filling of the filling mortar into the mega float 100 is completed.

Since each of the boxes 1 to 9 of the Mega Float 100 is filled with filling mortar without any gap, 19000 [m ³ ] of filling mortar is finally filled. When the filling mortar is filled in the megafloat 100, the weight of the filling mortar ensures that the megafloat 100 bottoms above the bottoming mound M.

In parallel with the filling work of the filling mortar, concrete blocks are piled up to create a block revetment.

After the Mega Float 100 has landed above the landing mound M, the upper part of the Mega Float 100 is lining with embankment J. For example, the upper part of the mega float 100 is paved with crushed stone C, which is the above-mentioned artificial ground material, to form a layer of embankment J. Then, the layer of crushed stone C is covered with a roadbed material such as soil, asphalt or concrete, and the upper part of the soil layer is paved.

As shown in FIG. 12, the megafloat 100 is fitted with a sacrificial anode X for corrosion protection. The sacrificial anode X is made of, for example, an aluminum alloy. Of the outer wall surface of the Mega Float 100, for example, a plurality of sacrificial anodes X are attached at intervals of 1 [m] on a portion in contact with seawater, and for example, a plurality of sacrificial anodes X are attached to a portion in the ground that is not in contact with seawater. Are installed at 3 [m] intervals.

Since the inside of the Mega Float 100 is filled with a filling mortar and becomes strongly alkaline, it has an anticorrosion effect. The sacrificial anode X is managed on a regular basis, and the anticorrosion effect on the Mega Float 100 can be updated by regular replacement or additional installation. As a result, the embankment for expanding the port facilities using the Mega Float 100 will be completed. The Mega Float 100 will be monitored by GPS survey even after the embankment is completed.

Next, the process flow of the embankment method using the Mega Float 100 will be described. FIG. 13 is a flowchart showing the process flow of the embankment method using the Mega Float 100.

First, preparatory work before construction is performed (step S10). Next, a defense embankment V is created on the revetment in the open culvert P of the port (step S12). Next, the Mega Float 100 is moved from the mooring position to a temporary position in the open culvert P (step S14). Next, a landing mound M is created in the open ditch P (step S16). In parallel with step S16, the ballast water inside the mega float 100 is discharged and decontamination work is performed (step S18). Next, the mega float is moved above the landing mound M (step S20).

Next, the inside of the mega float is filled with a filling mortar (step S22). A block revetment is created in parallel with step S22 (step S24). Next, a layer of embankment covering the upper part of the mega float is created (step S26). Next, the upper part of the soil layer is paved (step S28). Next, tidying up work is performed (step S30), and the embankment method using the mega float 100 is completed.

According to the embankment method using the mega float 100 described above, the port facility can be expanded by using the large floating structure. Further, according to the embankment method, by changing the moored mega float 100 to a port facility, it is possible to prevent the mega float 100 from drifting due to a natural phenomenon such as a tsunami.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention as well as the invention described in the claims and the equivalent scope thereof. For example, the above-mentioned embankment method may be applied to the extension of facilities at the water's edge such as a harbor or a lake.

1-9 Box 100 Megafloat B Crushed stone D Seabed covering soil layer E Cushion sheet F1 Mooring position F2 Temporary position F3 Landing position G Backhoe H Mass J Embankment K Slope M Landing mound P Opening mound Q Plant T Embankment U Club ship V Anti-impact embankment W Sea side impermeable wall X Sacrificial anode

Claims (5)

It is a method of embankment for expanding port facilities,
The process of crushing the solidified mortar mass to produce rubble and crushed stone,
The process of piling the rubble on the seabed on the revetment side of the port facility to create an embankment,
The process of laying the rubble on the surface of the seabed to create a bottoming mound,
The process of towing a floating structure above the landing mound and positioning it at the landing position,
A step of injecting seawater as ballast water into the floating structure to temporarily land the bottom at the landing position.
The process of discharging the ballast water inside the floating structure and
A step of filling the inside of the floating structure from which the ballast water is discharged with a filling mortar and landing the floating structure on the upper part of the landing mound.
A step of creating an embankment with the crushed stone on the upper part of the floating structure is provided.
Embankment method. The step of producing the crushed stone is
The process of laying the mortar on the ground and solidifying it to form lumps,
It comprises a step of crushing the solidified mass to generate the rubble.
The method of embankment according to claim 1. The step of discharging the ballast water is
A step of sequentially discharging the ballast water from the plurality of watertight compartments in a predetermined order so as to stabilize the inclination of the floating structure divided by the plurality of watertight compartments filled with ballast water is provided.
The method of embankment according to claim 1 or 2. The step of filling the filling mortar is
The step of filling the watertight compartment in at least one empty state with the filling mortar, and
A step of discharging the ballast water from at least one of the watertight compartments according to the filling amount of the filling mortar.
The method of embankment according to claim 3. The process of creating the embankment is
The process of crushing the crushed stone to generate crushed stone,
A step of laying the crushed stone on the upper part of the floating structure.
The embankment method according to any one of claims 1 to 4.

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