JP2001003332A - Immersion method for caisson and floater for immersing the caisson - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide immersion equipment for a caisson and a floater for immersing the caisson by which the caisson can be stably retained when towing it and immersed without use of a crane or a winch when immersing it. SOLUTION: For immersion of a caisson a wall-shaped caisson 10 which is inferior in the restoring property and unstable in the floating condition is towed and settled down at a specified position. In this case, float parts 21 of floaters 20 for immersing the caisson are arranged at both sides 15, 15 of the caisson 10 to suspend the caisson 10 by the floater 20 and set it afloat. The caisson is towed to an installation location together with the floater 20 in the condition that the caisson is set afloat and then, in the installation location of the caisson 10, ballast is tensed over the floater 20 and the caisson 10 to immerse the floater 20 and the caisson 10 together and settle them on the bottom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for laying a caisson such as a breakwater and a floater for laying. More specifically, the present invention relates to a method for towing a caisson (10) having an unstable wall shape and having an unstable stability by itself in a floating state to land on a predetermined installation location, and a floater used for the method.

[0002]

2. Description of the Related Art A caisson to be a seawall surrounding a seawall of a port breakwater or a landfill is a reinforced concrete box, and is manufactured on land or in a floating dock. After being installed at a predetermined position, sand, stones, and the like are packed inside, and a cover concrete is cast and installed.

In the prior art, as shown in FIG. 15, the caisson 10C has a substantially cubic shape and has good stability in rolling and pitching. It was possible to tow the 10C alone with a tugboat.

[0004] Therefore, the installation of this caisson 10C,
This self-sustained floating stable caisson 10C is towed by a tugboat 50 and the caisson 10C is installed at the caisson 10C installation site using a tugboat, crane ship, pulling winch, or the like.
After the positioning of the caisson, ballasts such as water, sand and gravel were stretched over the caisson 10C and seated on a mound on the seabed.

As another method, Japanese Patent Application Laid-Open No. 58-14 / 1983
In Japanese Patent No. 5590, a marine structure such as a concrete caisson or a concrete platform, which has a high center of gravity, is easily overturned, or has insufficient buoyancy and cannot rise by itself, is floated on the sea, towed, and laid at the installation position. Floaters for towing and sinking offshore structures have been proposed.

As shown in FIG. 16, the floater for towing and submersion of this proposal includes a float element 3 on both sides, a column 4 which is suspended vertically in front and behind the float element 3, a connecting truss 5 above the column, and a float. And a stopper 6 for connecting the rear portions of the element 3.

[0007] Then, using this sinking floater 7,
As shown in FIG. 17 (a), after the float element 3 of the floater 7 is sunk under the marine structure 1 on which the ears 2 are formed, the ballast of the floater 7 is drained as shown in FIG. 17 (b). The marine structure 1 is lifted by the floater through the ears 2 and towed in a state of being lifted, and at the time of sinking, water is injected into the marine structure 1 as shown in FIG. The marine structure 1 sinks while resisting the buoyancy of the floater 7. After the marine structure 1 has landed, as shown in FIG. 17 (d), the marine structure 1 is poured into the floater 7 to settle, the engagement between the ear 2 and the floater 7 is released, and the marine structure 1 is moved. 1 and the floater 7 are separated from each other to perform a series of towing and sinking operations.

[0008]

However, large-scale harbor facilities have been surrounded by breakwaters, and caisson heights have been increased due to the deep water at the locations where the breakwaters are installed. However, due to advances in design technology and manufacturing technology, the shape of the recent caisson itself has changed to be vertically long and changed, and there is a problem that conventional box-type caisson moving and sinking methods cannot cope with the problem.

In other words, the caisson of the new shape has only to be provided with a wall in the sea as a breakwater. Therefore, as shown in FIGS. 2 and 3, the caisson 10 has a wall shape, and the bottom of the wall 12 has a width. It has a shape with a footing 11 for preventing spread.

In the caisson 10 having the new wall shape, since the water line surface is elongated when floating, the restoring force against the roll becomes very small, and even when the roll is towed, the caisson 10 falls down. There is a problem that can not be towed while floating.

It is conceivable that the caisson 10 is transported in a falling state. However, in this case, it is difficult to close the opening and watertight, which is not practical.

In other words, there are cases where the top end of the caisson is temporarily closed with an air pillow or the like, but these are watertight enough to prevent seawater from entering due to waves, and maintain watertight even when water pressure due to water depth is applied. Not something you can do.

Further, the above-mentioned Japanese Patent Application Laid-Open No. 58-145590
16 and FIG. 17 using the floater 7 of Japanese Patent Application Laid-Open Publication No. H10-205, the ear 2 of the marine structure 1 is supported from above under the float element 3 and the marine structure 1 is raised. Therefore, if the floater 7 is not lifted and held after the positional relationship between the marine structure 1 and the floater 7 is made accurate during the floating and holding, the balance tends to be lost and the one ear 2 has an excessively large size. There is a problem that a load is easily applied.

In addition, when the marine structure 1 sinks, the ballast is not set up on the floater 7 side and the floater 7 is settled by the ballast on the marine structure 1, so that the floater 7 sinks as the marine structure 1 sinks. Since the draft of 7 is deepened and the buoyancy is increased, the load applied to the ear portion 2 continues to increase until it reaches the bottom. Therefore, there is a problem that not only the ears 2 need to be provided on the marine structure 1 but also the ears 2 need to have a rigid structure.

Further, if the ears 2 of a caisson or the like cannot be left, it is necessary to remove the ears 2 from the sea after the caisson is installed. However, there is no scaffolding, and there is no scaffolding. Working in a dangerous situation can be dangerous and inefficient.

Further, since it is necessary to stretch a ballast including a buoyancy increased by the sinking of the floater 7 to the marine structure 1 before the landing, there is a problem that the time until the landing is long.

Therefore, as shown in FIGS. 16 and 17,
This caisson 10 of the wall shape is transported to the installation sea area by the floating dock 40, and the caisson 10 is lifted by the crane ship 60,
It is conceivable that the caisson 10 is laid down by hanging it at the installation position.

However, in installing the caisson 10 using such a crane ship 60, the caisson 10
Since the weight of the caisson 10 is large, the large crane ship 60 is required, the cost of the installation work increases, and the caisson 10 cannot be installed at a low cost.

Further, when the large caisson is installed, the crane ship 3 cannot lift the caisson 10 in a self-propelled state. . For this mooring, for example, a large sea area as shown in FIG. 18 is occupied, so that the occupation area for the construction of the sea area at the time of installation becomes large, and there is a problem that a navigational obstacle and a fishing ground obstacle for general ships are caused. There is.

For example, the width Bc as shown in FIGS.
When a caisson 10 having a footing 11 with a length of 3 m, a length of Lc 25 m and a height of Hc 18.5 m is suspended by a crane ship 3 as shown in FIGS. 16 and 17, the suspension load of the caisson 10 is 500 tons. In addition to the tens of tons of the weight of the hanging balance 91 and the weight of the wire 92, and also the need for a hanging allowance, a crane ship of 700 ton class or more is required. The dedicated sea area shown in FIG.
It is as large as 0 m.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. It is an object of the present invention to keep a caisson in a stable state when towing a caisson, and to use a crane when a caisson is laid down. An object of the present invention is to provide a caisson sunk apparatus and a floater for caisson sunk which can sunk a caisson without using a ship or a winch.

[0022]

Means for Solving the Problems A caisson laying method and a caisson laying floater of the present invention for achieving the above objects are constituted as follows. 1) The method of laying a caisson according to the present invention is a method of laying a caisson in which a caisson having a wall-shaped shape, which has poor stability in itself and is unstable in a floating state, is towed to land at a predetermined installation location. The floats of the floater for laying the caisson are arranged on both sides of the caisson, the caisson is lifted by the floater and held in a floating state, and the caisson is towed to the installation location of the caisson together with the floater in the floated state. A ballast is attached to the floater and the caisson at a place where the caisson is installed, and the floater and the caisson are integrally settled so that the caisson is landed on a mound.

2) A more detailed method of laying a caisson according to the present invention is a method of laying a caisson that tow a caisson having an unstable wall shape and an unstable wall shape in a floating state to land on a predetermined installation location. A method wherein the floating dock equipped with the caisson and the floater for sinking the caisson is towed near the installation location of the caisson, the floating dock is settled until the floater floats, and the floated floater is moved. And arranging the float portion of the floater on both sides of the caisson across the caisson, connecting the caisson to a coupling beam that couples the float portion of the floater at an upper portion, and further connecting the floating dock after the connection. Is settled, the caisson is lifted by the floater and held in a floating state, and the caisson in the floating state is floated together with the floater. Pull out from the dock, tow to the caisson installation location, and at the caisson installation location,
Ballasting the floater and the caisson, sinking the caisson with the sedimentation of the floater, causing the caisson to land on the mound, and disconnecting the caisson from the floater after the caisson has landed. Features.

3) In the caisson sinking method described above, a load sensor is provided at a connection portion between the caisson and the floater, and ballast water is supplied when the ballast is applied to the caisson and the floater by the output of the load sensor. The posture of the caisson and the floater is adjusted by controlling the operation of the supply pump.

4) Further, in the above caisson setting method, the caisson and the floater are set at the place where the caisson is settled while the caisson is pulled in by a winch installed on the existing caisson. The caisson is landed.

5) The floater for laying a caisson is a laying caisson for towing a caisson having an unstable wall type and having an unstable wall shape by itself in a floating state to land on a predetermined installation location. A floater for
The floater is used for caisson lifting and towing.
A float is disposed on both sides of the caisson, and a coupling beam is formed at an upper portion of the float. The coupling beam forms the caisson when the caisson is received between the floats. It has a hanging portion that can be lifted, and the float portion has a ballast chamber that stretches a ballast when the caisson is laid down, thereby allowing the caisson and the floater to settle down integrally and allow the caisson to land on the mound. Further, when the caisson is being lifted, the draft of the float portion is always formed shallower than the draft of the caisson.

According to the present invention, in a caisson forming a breakwater or the like, a box-shaped caisson that can stably float by itself and can be towed as it is is stably floated by itself in a new shape. The background is that the caisson has changed into a wall-shaped caisson that is unstable when it is levitated because it can not be fallen.

One of the features of the present invention is that the caisson which is unstable in the floating state is lifted and held by a floater.

For this lifting, a wire, a chain, or other hanging metal fittings can be used. When the upper part of the caisson is hung, especially when the hanging parts are arranged on both sides of the upper part of the caisson, it is possible to prevent the moment from rolling. A large restoring force can be generated with a small load. In addition, the suspended load is the difference between the weight of the caisson including the ballast and the floater buoyancy, and these amounts can be adjusted by the ballast amount of the caisson and the floater, so that the required stability can be easily obtained by adjusting the suspended load. be able to.

The lifting of the caisson by the floater makes it easy to tow while keeping the caisson and the floater in a stable state, thereby solving the problem of towing the caisson.

Further, when the caisson is settling and landing work, the caisson is settled by injecting ballast water, but the floater always lifts the caisson, that is, the caisson is in a stable state in which the caisson is hard to fall in the rolling direction. It is settled as it is, and is set in place. Accordingly, the sinking and landing work can be safely performed while avoiding the danger of the caisson falling during the sinking and landing work of the caisson.

Another feature of the present invention is that the caisson and the floater holding the caisson are ballasted without using the unwinding of a hanging tool such as a wire for the sedimentation and settling of the caisson. It is to be performed by simultaneous settling. The sedimentation and landing work using the buoyancy avoids an increase in cost due to use of a crane or winch for lifting or hanging.

That is, when a crane or winch is used, the weight of the caisson is large, so that the crane, winch and wire must have enough capacity to support the caisson. Although it is necessary to hang the wire between the pulleys, the cost of the submersion work increases, but in the present invention, since the load of the caisson is not supported by the crane or winch, the crane ship and the winch and the power unit for this winch are unnecessary. It becomes.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A caisson laying method and a caisson laying floater according to an embodiment of the present invention will be described below with reference to the drawings. [Caisson] First, the caisson used in the present invention will be described.

As shown in FIGS. 1 to 3, the caisson 10 used in the present invention has a wall shape, has a footing 11 at the bottom of a wall portion 12, and has a hanging portion at a top end 14. This caisson is formed with 13 and has a poor recovery performance by itself in the floating state, making it difficult to tow in an independent state
It is 10.

This caisson 10 is made of reinforced concrete.
It is usually manufactured on a floating dock 40 shored near a breakwater. Further, the caisson 10 is not limited to a caisson for a breakwater, and may be a caisson having a window for underwater observation in a part of a submerged portion, such as an underwater observation deck.

As an example of the dimensions of the caisson 10, the width Bc of the top end 14 of the caisson 10, the length Lc 25m, and the height H
c18.5 m, the overhang width Be of the footing 11 at the bottom extends to both sides of 4 m each, and the total width Bt of the footing 11 is 13
m. [Floater] Next, a caisson sinking floater used in the caisson sinking method of the present invention will be described.

As shown in FIGS. 1 to 3, the floater 20 has a float portion disposed on both sides 15, 15 of the caisson 10.
21 and 21 and a combined beam 22 that connects the floats 21 on both sides on the upper side. In the above floating state, the stability is poor and the caisson 10 is unstable and towed to the sinking position,
When the caisson 10 is laid, the caisson 10 is settled together with the caisson 10 by injecting ballast water.

The floater 20 is connected to the floats 21 and 21 on both sides by a connecting beam 22 to form a portal when viewed from the front, and a hanging portion 23 is provided at the lower center of the connecting beam 22. This hanging part 23 and the hanging part 13 of the caisson 10 are
So that the floats 22 are arranged on both sides 15 and 15 of the caisson 10, and the caisson 10 sandwiched between the floats 21 and 21 is lifted and held by the suspension 23 of the combined beam 22. Be composed.

Further, the float portion 21 of the floater 20 is provided with a ballast chamber into which ballast water for adjusting buoyancy can be injected and a gravity drain valve for draining the ballast water from the ballast chamber. By injecting and discharging the ballast water into the chamber, the ballast water can be settled and floated within a predetermined range. The float part 21 of the floater 20
Is made of a steel plate, and the coupling beam 22 is made of a steel material.

In the structure shown in FIGS. 1 to 3, the coupling beam 22 is provided at four positions. However, the number of the coupling beam 22 is not limited to the four positions. Determined by how caisson 10 is suspended. Further, it is not always necessary to divide the structure, and the structure may be fully extended in the front-rear direction.

According to the floater 20 having the above configuration, the following effects can be obtained. In other words, when the caisson 10 is towed, the caisson 10 is towed by the tugboat 50 in a hung state, but since the caisson 10 is in the hung state, it is towed in a stable state without falling down, and the floater 10 itself is towed. The float portions 21, 21 arranged on both side portions 15, 15 of the 10 have large restoring performance. Therefore, the caisson 10 and the floater 10 can be towed in a stable state.

At the same time, since the floater 20 is configured to be able to settle and float within a predetermined range, when the caisson 10 is laid down, ballast is applied to the ballast chamber of the floater 20 and the ballast chamber of the caisson 10. , The floater 20 sinks with the caisson 10
10 can be lifted and landed on the seabed at the installation location.

Since the caisson 10 is settled and settled by the settling of the floater 20, a winch for unwinding the hoisted caisson 10 is unnecessary. Therefore, the winch, the pulley group for unwinding, and the Since a power source such as a generator for driving the winch is not required, the cost of the apparatus required for the sedimentation and landing work can be reduced.

To illustrate the specific size of the floater 20, as the floater 20 holding the caisson 10 whose dimensions have been described above, the float portion 21 on one side has a width Bf4.
m, length Lf21m, depth Df10m, and Sf between the two floaters 21, 21 is 4 m.
The coupling beam 22 for coupling 21 is provided at four locations and has a cross section of 2 m.
× 2 m (Lc × Dc, Bc × Lc). The height Hc of the combined beam 22 is 4 m, the clearance Hs between the top end 14 of the caisson 10 when the caisson 10 is lifted (hung allowance) Hs is 0.5 m, and the side portions of the caisson side portion 15 and the float portion 21. Is 0.5 m, and the minimum freeboard is Ffs of 0.5 m.
m.

[Caisson Sinking Method] Next, a caisson sinking method using the above-described caisson sinking floater 20 will be described with reference to FIGS.

1) Manufacture of the caisson and transportation to the installation sea area As shown in FIG. 4, the manufacture of the caisson 10 is performed on the main deck 41 of the floating dock 40, and the completed caisson or caisson 1 is manufactured.
The floating dock 40 is placed on the floating dock 40, and the floating dock 40 is towed by the tug boat 50 and transported to the sea area where the caisson 10 is installed. When transporting the caisson 10, the floater 20
Are also transported mounted on the same floating dock 40.

In this case, since the caisson 10 has the footing 11 for preventing the fall of the caisson 10, the caisson 10 is stably placed on the floating dock 40. In this state, the floating dock 40 is towed by the tug boat 50 or the like, so that the caisson does not fall down.

When the ship reaches the sinking sea area in or near the installation sea area, the towed floating dock 40 is anchored and moored in the sinking sea area. The sinking sea area is a working sea area having a water depth necessary for the sinking of the floating dock 40 when the caisson 10 is pulled out.

2) Settling of the floating dock After the floating dock 40 is moored in the sinking sea area, a ballast is set up in the ballast room of the floating dock 40, and
To settle. Due to this sinking, the floater 20 on the main deck 41 of the floating dock 40 floats at the draft df0, while the caisson 10 has not yet floated and remains upright on the main deck 41. Further, the floating dock 40 is lowered and the caisson 10 is sunk until the combined beam 22 of the floater 20 reaches a predetermined depth at which the beam can cross over the top end 14 of the caisson 10.

3) Holding the caisson by the floater and floating the caisson After the floating dock 40 is settled to a predetermined depth, the draft df0 is supported by the tugboat 50 support as shown in FIGS.
Caisson 10 floats 21 and 21 of floater 20
The floater 20 is moved to a position where the floater 21, 21 and the combined beam 22 hold the caisson 10 from above along the both sides 15, 15.

At this time, a gap Bs is generated between the float portion 21 and the side portion 15 of the caisson 10. In this gap Bs, an old tire for cushioning a collision, etc. The cushioning material 32 is sandwiched.

Next, as shown in FIG. 6, the suspension 13 on the upper part of the caisson 10 and the suspension 23 of the combined beam 22 are connected by a suspension 30 such as a wire or a chain. At this time, the floating dock 40 is set so that the distance between the hanging portion 13 of the caisson 10 and the hanging portion 23 of the combined beam 22 is shorter than the distance when the caisson 10 is lifted and held so that the hanging tool 30 can be easily connected.
The sedimentation depth of the hangers 30 is adjusted to perform the connection work of the hanging members 30.

After the work of connecting the hanging members 30 is completed, the floating dock 40 is further lowered. Due to this sedimentation, the gap between the combined beam 22 and the top end 14 of the caisson 10 becomes large, so that the load of the caisson 10 is applied to the combined beam 22 and a lifting state as shown in FIG. 7 is obtained.

When the sinking of the floating dock 40 further proceeds, the draft of the caisson 10 becomes a predetermined draft dc0, the draft of the floater 20 changes from df0 to df1, the caisson 10 is suspended by the floater 20, and the draft of the main deck 41 becomes higher. Levitate away.

When the caisson 10 floats, a hanging pump is used by using a general-purpose pump mounted on the floating dock 40.
When the load of the caisson 10 starts to be applied to 30, the water ballast is sent to the floating ballast chamber of the floater 20 to adjust the eccentric load of the caisson 10.

A wire, a chain, or other suspending metal can be used as the suspending implement 30, and the suspending load at this time is a difference between the weight including the ballast of the caisson 10 and the buoyancy of the floater 20. Since the draft can be changed by adjusting the draft of the caisson 10 and the floater 20, that is, the ballast amount, the state of the caisson can be easily stabilized.
By lifting the caisson 10 by the floater 20,
The caisson 10 and the floater 20 can be towed while maintaining a stable state.

Further, since the lever is restored above the caisson 10, the lever for restoring moment against rolling becomes large. Therefore, it is preferable to suspend the caisson 10 at the top end 14 as shown in FIGS. 1 to 3. By lifting the upper part of the caisson 10, the stability of the caisson 10 is significantly improved.

4) Movement and positioning of the caisson lifted by the floater Next, as shown in FIG. 8, the raised caisson 10 is pulled out from the floating dock 40 together with the floater 20 by the tugboat 50 as shown in FIG. The caisson 10 and the floater 20 are moved to an installation location, for example, a location adjacent to the existing caisson 10A, and the tugboat is moved as shown in FIG.
50 supports and pulling winch on existing caisson 10A
The caisson 10
And the floater 20 are held at a predetermined settling place.

When there is no existing caisson, the caisson 10 is held at a predetermined sinking position by extending or retracting the anchored mooring line and supporting the tugboat 50.

5) Settling and landing of caisson A ballast is attached to the caisson 10 that has been able to maintain its position and the floater 20 that is lifting the caisson.
Then, the caisson 10 is settled on the mound 80 in the state shown in FIGS.

The ballasting is performed by sending ballast water to a ballast room of the caisson 10 or a ballast room of the floater 20 through a water supply hose 74 by a ballast pump 73 temporarily provided in the existing caisson 10A. By the way, 1,000
Ballasting of about ton ends in about 4 hours.

When a ballast is set up on the caisson 10 and the floater 20, a load sensor such as a load cell (tensile meter) is connected to the connecting portions 13, 23 and 30 between the caisson 10 and the floater 20.
31 (FIG. 2), the operation of the ballast pump 74 for supplying ballast water to the ballast chambers of the caisson 10 and the floater 20 is automatically or manually controlled by the output of the load sensor 31, and the caisson 10 and the floater Adjust the sinking posture of 20. Thereby, the sedimentation and landing work can be performed smoothly. In particular, it is convenient to automatically start and stop the ballast pump 73 based on the output of the load sensor 31 to control the water supply to each ballast chamber.

In the ballasting work, the caisson 10 is also settled while adjusting the injection of ballast water, and the caisson 10 is kept in a state where the floater 20 is constantly lifted, so that the caisson 10 is hard to fall in the roll direction. Settle down in a stable state and install in place. Thus, the sinking and landing work can be safely performed while avoiding the danger of the caisson 10 falling during the sedimentation and landing work of the caisson 10.

During the sedimentation and landing work, the position is held by the pull-in wire 72 and the support of the tug boat 50. The positioning winch 71 for driving the pull-in wire may be provided on the already installed caisson 10A, or may be provided on the floater 20 and the leading end of the wire may be connected to the existing caisson 10A. 6) Installation of caisson and detachment of floater After the caisson 10 has landed on the mound 80, and after confirming the final position, add an additional ballast to the caisson 10 to stabilize it. The caisson 10 will eventually be ballasted with sand or gravel and will be covered with concrete at the top 14 to become a breakwater.

Next, the caisson 10 is separated from the floater 20 by further ballasting the floater 20 and lowering the floater 20 until the hanger 30 can be opened, for example, until the hanging wire is loosened. In this state, the hanger 30 is released, and the caisson 10 and the floater 20 are separated.

7) Lifting and setting of the next caisson When several caissons 10 and 10 are mounted on the floating dock 40, after the caisson 10 is separated, the ballast in the floater 20 is drained, and Float until the draft df0 is reached where it can be retracted, and when it becomes possible to retract, return to the floating dock 40 by towing the tugboat 50, repeat the above 3) to 6), and lift and hold the caisson 10 to be installed next Then, the caisson 10 is moved, positioned, settled, settled, settled, and the floater 20 is separated.

8) Storing the Floater on the Floating Dock and Returning to the Port Install the last caisson 10 mounted on the floating dock 40,
After separating the caisson 10, the ballast in the floater 20 is drained and floated until it can be mounted on the floating dock 40.
When the loadable draft df0 is reached, the shallow draft floater 20 is pulled in by the tugboat 50. After the floater 20 is retracted, the floating dock 40 is raised, and the floater 20 is placed on the main deck 41 of the floating dock 40.After this placement, the gravity drain valve of the floater 20 is opened, and the ballast in the floater 20 is removed. After draining, the floater 20 is fixed to the floating dock 40. If the floater 20 is fixed to the floating dock 40, the floating dock 40
The anchor is lifted to release the mooring, and as shown in FIG. [Effects] According to the caisson laying method described above, the following effects can be obtained.

1) Ensuring the stability of the caisson during towing When the caisson 10 is pulled out of the floating dock 40 and towed to the installation position, the floater 20 having excellent stability is used for the caisson.
The caisson 10, which cannot be towed by itself because of its lack of stability, is lifted and held in a stable state and towed in a stable state, so that the danger of the caisson 10 falling during towing can be eliminated. .

2) Ensuring the stability of the caisson at the time of settling and landing work The sinking and landing work of the caisson 10 is performed simultaneously by keeping the caisson 10 on the floater 20 side while keeping the floater 20 and caisson 10 at the same time. Since the caisson 10 is settled and settled, the caisson 10 can always maintain a stable state in which the caisson 10 is hard to fall in the roll direction. Therefore, the sinking and landing work can be safely performed while avoiding the danger of the caisson 10 falling during the sedimentation and landing work of the caisson 10.

3) Settling and Bottoming of Caisson by Ballasting In addition, the caisson 10 is settled and settled by ballasting the caisson 10 and the floater 20 together.
A large crane ship for lifting and suspending the caisson 10 is not required. Because it does not require not only the crane ship but also the large sea area occupied by this crane ship,
The caisson 10 can be laid down even when it is not possible to occupy a small sea area or a large sea area for construction. Also, since no crane ship is required, construction costs can be reduced.

Further, the caisson 10 and the floater 20 are settled down by ballasting, so that the caisson 10 is settled. Therefore, a winch for winding and unwinding the caisson 10 and a power source for the winch are not required.

4) Improvement of Workability by Suspension Holding The caisson 10 is configured to be lifted.
Caisson 10 with floating dock 40 main deck 41 or mound 80
In a state of being upright at the same time as this lifting device 30 for lifting.
Is performed after the position is set so that it is easy to set and release.
The ceiling 14 of the caisson 10 is used as a stable scaffold and can be easily operated. Therefore, safety and work efficiency are remarkably improved.

In addition, since the holding is performed by lifting,
Even if the relative position between the caisson 10 and the floater 20 is slightly deviated, the work can be performed, and after the hoisting, the work is stored at a predetermined relative position. Therefore, it is not necessary to perform the positioning during the hoisting with high precision.

The relative movement of the caisson 10 and the floater 20 in the height direction can be performed very easily and safely by changing the draft of the floating dock 40 and the draft of the floater 20.

5) Ease of positioning of the caisson 10 Further, the positioning of the caisson 10 is performed by supporting the tugboat 50 and winding the wire 72 of the positioning winch 71 temporarily installed on the existing caisson 10A.
The positioning can be easily performed, and the working efficiency can be improved.

Further, since the positioning pull-in winch 71 only needs to have a driving force necessary to move the floating floater 20 and the caisson 10 lifted by the floater 20, the positioning winch 71 is relatively simple. A small winch will suffice.

[0078]

According to the caisson laying method and the caisson laying floater of the present invention as described above,
The following effects can be obtained. 1) When the caisson is towed, the caisson is sandwiched by a floater with excellent stability, and the caisson that cannot be towed due to insufficient stability by itself is held at the top of the caisson to make it stable, and the floater is towed together with the caisson. , Because the towed floater itself has a great stability
Eliminates the risk of caisson tipping during towing, and enables stable towing. 2) The caisson is settled and settled by ballasting the caisson and the floater so that the caisson is settled in a stable state with the floater lifted, so that the danger of the caisson falling over can be avoided, and the caisson can be safely settled and settled. Landing work can be performed. 3) In addition, the floater causes the floater to settle and float by injecting and draining ballast water, and when the caisson is laid, the floater is settled together with the suspended caisson, and the caisson is settled on the seabed at the installation position. Large crane vessels for lifting and hanging and winches for lowering are not required.

When a crane ship is not required, a large sea area occupied by the crane ship is not required, and the work occupied area can be small. Construction work can be carried out even when a large sea area cannot be occupied.

Since neither a winch nor a power source for lowering the caisson is required, the cost of the apparatus required for the sedimentation and landing work can be reduced. 4) Since the caisson is connected to and released from the floater in a state where the caisson stands upright on the floating dock or mound, and furthermore, the caisson is placed in such a position that it can be easily set and released. It can be easily performed by using the top end as a stable scaffold, and it is safe and work efficiency is significantly improved. 5) Moreover, since the holding work is carried out by lifting, the connecting work becomes an easy work such as hanging a wire.
The work can be performed even if the relative position between the caisson and the floater is shifted, and after the hoisting, the work is stored in a predetermined relative position. Therefore, the positioning at the time of hoisting does not need to be performed with high precision, and the working efficiency is remarkably improved. 6) Furthermore, since the caisson is positioned in a floating state, the position can be changed with a small force. In addition, since the caisson has a stable posture in a suspended state, it can be easily positioned, and work efficiency can be improved. Is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a caisson and a sinker floater according to the present invention.

FIG. 2 is a front view showing a caisson according to the present invention and a floater for submerging.

FIG. 3 is a side view showing a caisson according to the present invention and a floater for submerging.

FIG. 4 is a schematic plan view showing a state in which a caisson and a floater are transported by a floating dock in the method of submerging the caisson according to the present invention.

FIG. 5 is a schematic plan view showing a state in which a floater is straddled over a caisson in the method of submerging the caisson according to the present invention.

FIG. 6 is a schematic front view showing a state in which the floater is laid on the caisson in the method of submerging the caisson according to the present invention.

FIG. 7 is a schematic front view showing a state in which the caisson is lifted by the floater in the method of submerging the caisson according to the present invention.

FIG. 8 is a schematic plan view showing a state of being lifted to a caisson by a floater and pulled out from a floating dock in the method of submerging the caisson according to the present invention.

FIG. 9 is a schematic plan view showing a state of being lifted to a caisson by a floater and towed to a predetermined sunk position in the caisson squatting method according to the present invention.

FIG. 10 is a schematic plan view showing a caisson positioning state in the caisson sinking method according to the present invention.

FIG. 11 is a schematic plan view showing a caisson sunk state in the caisson squatting method according to the present invention.

FIG. 12 is a schematic side view showing a caisson sunk state in the caisson squatting method according to the present invention.

FIG. 13 is a schematic side view showing a caisson landing state in the caisson laying method according to the present invention.

FIG. 14 is a schematic side view showing a state in which a floater and a floating dock mounted on the caisson are set aside in the caisson laying method according to the present invention for returning to a port.

FIG. 15 is a perspective view showing a state in which a box caisson of the related art is towed.

FIG. 16 is a perspective view showing a prior art floater.

FIGS. 17A and 17B are explanatory diagrams showing a use state of a conventional floater, wherein FIG. 17A shows the sinking of the floater, FIG. 17B shows the floating and holding of the marine structure, FIG. d) shows detachment of the floater.

FIGS. 18A and 18B are explanatory views showing lifting of a caisson in a method of submerging a wall-shaped crane using a crane ship, wherein FIG. 18A is a side view, and FIG.

19A and 19B are explanatory views showing lifting and landing of a caisson in a method of sinking a wall-shaped crane using a crane ship, wherein FIG. 19A is a side view and FIG.

FIG. 20 is a plan view illustrating an occupied sea area by mooring lines in a method of submerging a wall-shaped crane using a crane ship.

[Description of Signs] 10, 10A Caisson 11 Footing 13 Suspended part 15 Side part 20 Floater 21 Float part 22 Combined beam 23 Suspended part 30 Hanging tool 31 Load sensor 40 Floating dock 41 Main deck 71 Winch (retract winch) 73 Pump (ballast) Pump) 80 mound

Continued on the front page (72) Inventor Toshio Komiya F-term (reference) 2D018 BA12 in Mitsui Engineering & Shipbuilding Co., Ltd. 5-6-4 Tsukiji, Chuo-ku, Tokyo

Claims (5)

[Claims] 1. A caisson squatting method for towing a caisson having an unstable wall shape and having an unstable stability by itself in a floating state to land on a predetermined installation location, wherein the caisson is provided on both sides of the caisson. The floater of the floater for submerging is placed, the caisson is lifted by the floater and held in a floating state, and the caisson is towed to the installation location of the caisson together with the floater while the caisson is floated, and the installation location of the caisson The method of claim 1, wherein a ballast is stretched over the floater and the caisson, the floater and the caisson are integrally settled, and the caisson is settled on a mound. 2. A caisson squatting method for towing a caisson having an unstable wall shape and having an unstable stability in a floating state by itself to land at a predetermined installation location, wherein the caisson and the caisson are sunk. The floating dock equipped with the floater is towed near the installation location of the caisson, the floating dock is settled until the floater floats, the floated floater is moved, and the float portion of the floater is straddled over the caisson. Are arranged on both sides of the caisson, and the caisson is connected to a combined beam that connects the float part of the floater at the top, and after this connection,
The floating dock is lowered, the caisson is lifted by the floater and held in a floating state. A ballast on the floater and the caisson, settle the caisson together with the sedimentation of the floater, and settle the caisson on the mound.After the caisson has settled, the caisson and the floater A caisson squatting method characterized by disconnecting the connection. 3. A load sensor is provided at a connection between the caisson and the floater, and the output of the load sensor controls the operation of a pump that supplies ballast water when ballasting the caisson and the floater. The method of claim 1, wherein the postures of the caisson and the floater are adjusted. 4. A caisson installation location where the caisson and the floater are settled, and the caisson is settled by a winch installed on an existing caisson while pulling in the caisson. The method for laying a caisson according to claim 1. 5. A floater for sinking a caisson for towing a caisson having an unstable wall shape and having an unstable stability by itself in a floating state and landing at a predetermined installation location, wherein the floater is During caisson lifting and towing,
A float is arranged on both sides of the caisson, and is formed having a coupling beam that couples the float at the top, and the coupling beam forms the caisson when the caisson is received between the floats. The float unit has a ballast chamber that allows a caisson and a floater to settle down integrally and settle the caisson on a mound by setting a ballast when the caisson is laid down. Further, the draft of the float portion is always shallower than the draft of the caisson when the caisson is being lifted.