JP6914411B1 - Pile construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pile construction method capable of controlling a load of a pile when raising the pile and realizing a gentle and safe raising work of the pile. SOLUTION: A pile 10 having a hollow main body 1 and having a valve 5 having a diameter smaller than that of the main body 1 at the lower end of the main body 1 is driven into a water bottom 100. The construction method includes a water injection step of raising a pile 10 lying on the water 101 on the water 101 while allowing water to flow into the main body 1 through a valve 5 on the lower side. [Selection diagram] Fig. 6

Description

The present invention relates to a method of constructing piles used for a monopile foundation or the like of a fixed offshore wind power generator.

Currently, a method of installing a monopile (pile) is used as an example of the basic structure of an offshore fixed wind power generator. The piles are transported to the installation site on the ocean in a state of being laid down on a transport ship or a work ship, and are erected at the installation site. After that, it is fixed to a pile gripper mounted on the work ship and placed under the seabed.
When raising a monopile at sea, the weight is relatively small, and in the case of short piles, it can be raised by a crane on a transport ship or a work ship. However, when the pile weight is heavy and long, it may not be possible to stand up on a transport ship or a work ship due to restrictions on the crane lifting capacity and lift.
In that case, the following construction method is used. (1) Attach water stop plates to the upper and lower ends of the pile, (2) Lift the pile transported to the installation site once, (3) Drop the lifted pile to the sea surface and put it in a floating state, (4) Pile Hold the upper end with a crane, (5) Remove the water stop plate at the lower end of the pile and let water flow into the pile to raise the pile vertically, (6) At this time, the valve installed on the water stop plate at the upper end The posture is controlled by releasing the internal pressure (see Patent Document 1 below).
In addition, in the installation of floating offshore wind turbines, a construction method is used in which water or seawater is injected into the foundation of the wind turbine after being transported in a floating state to the installation location offshore so that it can stand on its own without using a crane. (See Patent Document 2 below).

UK Patent Application Publication No. 2560006 Japanese Unexamined Patent Publication No. 2012-201217

However, in the conventional method of removing the water blocking plate provided on the monopile (pile), seawater suddenly flows into the pile and the lower end of the pile sinks vigorously. At that time, a shocking load acts on the crane holding the pile. At this time, if the crane lifting capacity is not sufficient for the pile weight and impact load, the crane may be damaged. Furthermore, the behavior of the pile during erecting cannot be controlled, which may damage the equipment and construction jigs installed on the pile. In addition, if the crane has insufficient lifting capacity, it is necessary to raise it at a position with a short working radius, and the inertial force of the pile immediately after raising may cause the pile to come into contact with the crane boom and damage the crane. ..

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a construction method capable of controlling a load acting on a crane when erecting a pile and realizing a safe erecting. And.

In order to solve the above problems, the present invention proposes the following means.
The method according to the present invention is a method of constructing a pile which is provided with a hollow main body and has an inflow port having a diameter smaller than that of the main body at the lower end of the main body. Therefore, the pile is provided with a water injection step of raising the pile lying on the water on the water while allowing water to flow into the main body through the inflow port.

According to the present invention, the lower end of the pile has an inflow port having a diameter smaller than that of the main body. As a result, the pile can be raised gently by relaxing the raising speed at the initial stage of water injection into the pile, as compared with the case where the pile is not provided with an inflow port and the entire diameter of the pile is opened. Further, by gently erecting the pile, for example, it is possible to reduce the inertial force when aligning the pile after erecting with the driving position. Therefore, for example, it is possible to prevent an impact load from acting on the crane when raising the pile. Further, when raising the pile, for example, the apparent weight of the pile with respect to the crane can be reduced. As a result, when the pile is raised by the crane, the load of the pile applied to the crane can be minimized. That is, it is possible to provide a construction method capable of controlling the load of the pile when raising the pile and realizing safe raising.

Further, the inflow port may be opened and closed by an external operation.

According to the present invention, the inflow port is opened and closed by an external operation. As a result, the amount of water flowing into the pile can be controlled at any time. As a result, the load transmitted from the pile to the crane can be controlled more efficiently, and a safe upright can be realized.

Further, in the water injection step, air may be discharged from the main body while flowing water from the inflow port.

According to the present invention, air is discharged from the main body while water is flowing in from the inflow port. Here, discharging the air from the main body includes providing a hole in the main body and discharging the air from the main body through the hole, and a water stop plate provided separately from the main body (described later). It also includes discharging the air from the main body from the valve or the like. Therefore, for example, as compared with the method of not discharging the air from the main body, it is not necessary to let the air escape from the inflow port, and the water can flow into the pile more efficiently.

Further, in the water injection step, the inflow amount of water from the inflow port may be controlled so that the water surface inside the pile is lower than the water surface outside while the pile is vertically raised.

According to the present invention, the amount of water flowing in from the inflow port is controlled so that the water surface inside the pile is lower than the water surface outside when the pile is vertically raised. That is, the pile in this state has buoyancy by the difference between the water surface between the outside and the inside. As a result, the load of the pile (apparent weight of the pile) acting on the crane that pulls up the pile when raising the pile is reduced by the amount of buoyancy, as compared with the case where the water surface inside the pile and the water surface outside are the same. Can be done. Therefore, the load on the crane when lifting the pile can be reduced.
Furthermore, by reducing the load on the piles acting on the crane, the crane capacity can be increased. Therefore, the boom of the crane can be tilted at the time of lifting. Therefore, it is possible to extend the working radius of the crane at the time of raising and increase the distance between the crane boom and the pile. This extends the safe distance between the crane boom and the pile, and prevents the pile from coming into contact with the work boat or crane even if the pile tilts or approaches the work boat due to inertial force immediately after the pile has been raised. It can be avoided.

Further, a water blocking plate may be provided at the lower end of the main body of the pile, and a removal step of removing the water blocking plate from the pile after the water injection step is completed may be included.

According to the present invention, the water stop plate is removed from the pile after the water injection process is completed. That is, after the alignment step, water injection into the pile is restarted, and after completion, the water stop plate is removed from the main body. As a result, when aligning the piles, it is possible to allow a margin in the crane capacity.

Further, a step of suspending the pile to the bottom of the water may be included before the removal step.

According to the present invention, the pile is hung on the bottom of the water before the step of removing the water stop plate. That is, when the pile is suspended from the bottom of the water, the air inside the pile is not evacuated by not removing the water blocking plate, and the pile is suspended from the bottom while maintaining the buoyancy of the pile. Thereby, for example, even when the crane capacity is insufficient with respect to the weight of the pile, the pile can be suspended to the bottom of the water by utilizing the buoyancy.

Further, the water injection start marking may be provided on the main body of the pile, and the water injection step may be started when the water injection start marking overlaps the water surface.

According to the present invention, the water injection process is started when the water injection start marking overlaps the water surface. Thereby, the timing of the start of the inflow of water can be easily visually determined.

Further, a water injection possibility determination marking may be provided on the main body portion of the pile, and the start possibility of the water injection process may be determined based on the positional relationship between the water injection possibility determination marking and the water surface.

According to the present invention, it is determined whether or not the water injection process can be started based on the positional relationship between the water injection possibility determination marking and the water surface. As a result, for example, if it becomes difficult to continue the pile lifting process due to a crane failure during the pile lifting process, even if water injection is started without reaching the planned lifting height. , It is possible to easily visually judge whether the pile can be raised without exceeding the capacity of the crane and without contacting the seabed.

Further, a lifting step of lifting the upper end of the pile with a crane is included, and in the water injection step, the pile may be raised by using the crane.

According to the present invention, the step of lifting the upper end of the pile with a crane is included. As a result, the lower end of the pile can be positively submerged under the water surface. Therefore, water can flow into the pile more efficiently.

Further, in the water injection step, the behavior of the pile may be controlled by opening and closing the inflow port according to the load of the crane and controlling the amount of water injected into the pile.

According to the present invention, the behavior of the pile is controlled by controlling the amount of water injected into the pile according to the load of the crane. As a result, the state of the pile can be managed more precisely. That is, the pile can be erected more safely.

Further, in the middle of the water injection process, the water injection is interrupted once when the pile is vertically raised, and the position of the pile is adjusted to a predetermined driving position by raising the crane. You may be.

According to the present invention, when a pile is vertically raised in the middle of a water injection process, water injection is interrupted once, and the position of the pile is adjusted to a predetermined driving position by raising the crane. That is, in the water injection process, the pile is raised vertically using a crane. After that, the inflow port is closed and the water injection work is interrupted. After that, the crane is raised and the position of the pile is adjusted to a predetermined driving position. After that, water injection into the pile is resumed.
This makes it possible to maintain the buoyancy acting on the pile during the alignment process. That is, it is possible to have a margin in the crane capacity. Therefore, even when a dynamic load is applied to the crane due to the shaking of the pile due to wind and tidal current, the work can be safely performed without exceeding the crane capacity.
Further, even if the pile is shaken by the wind and the tidal current when aligning the pile, it is possible to wait until the shaking is settled while ensuring a sufficiently safe separation between the work boat and the pile. As a result, the piles can be safely aligned without contacting the peripheral equipment.

Further, in the lifting step, the water injection step may be started when the height of the pile reaches the lift of the crane.

According to the present invention, the water injection process is started when the height of the pile lifted by the crane reaches the lift of the crane. That is, by lifting the upper part of the pile to some extent before the water flows into the pile, the lower part of the pile is sunk below the water surface. By starting the inflow from such a state, the water pressure applied to the inflow port can be increased as compared with the case where the water injection is started before the upper part of the pile is lifted. That is, it is possible to increase the flow rate that flows in from the inflow port of the same size. Therefore, water can flow into the pile in a shorter time.

Further, in the lifting step, the pile having a mass exceeding the rated load of the crane may be lifted by using buoyancy.

According to the present invention, a pile having a mass exceeding the rated load of the crane is lifted by using the buoyancy acting on the pile. As a result, even when the performance of the crane that can be used on the water is limited, the pile can be erected by the crane. Therefore, the performance required for the crane is lower than that when the buoyancy acting on the pile is not used, the safety during construction can be improved, and the cost required for construction can be further reduced.

Further, in the water injection step, the pile having a length exceeding the lift of the crane may be raised by submerging the lower part of the pile in water.

According to the present invention, a pile having a length exceeding the lift of a crane is raised by submerging the lower part of the pile in water. As a result, even when the performance of the crane that can be used on the water is limited, the pile can be erected by the crane. Therefore, the performance required for the crane is lower than that when the buoyancy acting on the pile is not used, the safety during construction can be improved, and the cost required for construction can be further reduced.

Further, after the water injection step, a drainage step of injecting air into the main body and discharging water from the inflow port may be included.

According to the present invention, a drainage step of injecting air into the main body and discharging water from the inflow port is included.
Here, when a crane breaks down or sudden weather deterioration occurs during pile construction, it may be necessary to interrupt or redo the water injection process. At this time, air is press-fitted into the main body and water is discharged from the inflow port. As a result, the construction work can be interrupted and redone as necessary. Therefore, the safety of the construction work can be further improved.

According to the present invention, it is possible to provide a construction method capable of controlling a load acting on a crane when erecting a pile and realizing a safe erecting.

It is a figure which shows the state which the pile of the embodiment which concerns on this invention is driven into the water bottom. It is a figure of the pile of the embodiment which concerns on this invention. FIG. 2 is a view in which a transport vessel on which the piles of FIG. 2 are mounted are on the side of a work vessel. It is a figure which the stake of FIG. 3 is moving by a tugboat. It is a figure which takes measures to prevent rotation before erecting the pile of FIG. It is a figure which shows the state which the pile of FIG. 5 stands upright on the water. FIG. 6 is a diagram showing water flowing into the pile. It is a figure which shows the state which the pile of FIG. 6 is vertical. It is a figure which installs the pile of FIG. 8 in a pile gripper. FIG. 9 is a diagram in which the pile of FIG. 9 is driven into the water bottom with a hydraulic hammer. This is a modified example in which the pile of FIG. 2 is marked. It is a figure which shows the modification of the angle management method while raising a pile. This is a modified example in which the upper end of the pile according to the present embodiment is trapezoidal.

Hereinafter, a pile and a pile construction method according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the pile (monopile) 10 includes a main body 1, an upper water stop plate 2, an upper valve 3, a lower water stop plate 4, and a lower valve 5. And have. The pile 10 is used as a foundation for installing a wind turbine or the like on water such as the sea. At this time, the pile 10 is composed of only the main body 1, and the water blocking plates 2, 4 and the valves 3 and 5 are removed from the main body 1. Then, the lower end of the pile 10 is driven into the water bottom 100. The upper end of the pile 10 protrudes from the water 101. The inside of the pile 10 is also filled with water 102. The water surface of the water 102 inside the stake 10 is at the same height as the water surface of the water 101 outside the stake 10.

The main body 1 is formed in a columnar shape, for example. The inside of the main body 1 is hollow. After driving the main body 1, for example, a wind turbine is installed at the upper end of the main body 1. Therefore, it is necessary to have a size that can sufficiently withstand external forces such as wind and waves. As an example, the main body 1 has a diameter of 10 m, a plate thickness of 70 mm, a height of 85 m, and a weight of 1900 tons.
Further, as shown in FIG. 13, the upper part of the main body 1 may be trapezoidal.

The upper water stop plate 2 is removably arranged at the upper end of the main body 1. The upper water stop plate 2 seals the upper end of the hollow main body 1. The upper water stop plate 2 has, for example, a disk shape. The outer diameter of the upper water stop plate 2 is about the same as the inner diameter of the main body 1. The upper water stop plate 2 has a strength that can withstand fluctuations in the internal pressure of the main body 1. The detailed dimensions of the upper water stop plate 2 are appropriately determined. The upper water stop plate 2 is fitted inside the columnar main body 1. At that time, the gap between the main body and the main body 1 can be switched between sealing and opening by, for example, a mechanism using a hydraulic drive as a drive source.

Further, the upper water stop plate 2 may also be used as a hanging jig. The hanging jig is used for equipment for pulling up the pile 10 when raising the pile 10 floating on the water (described later).

The upper valve 3 penetrates the upper water stop plate 2 in the vertical direction. The upper valve 3 has a diameter smaller than the outer diameter of the main body 1. The upper valve 3 is provided with, for example, a pressure resistant hose (not shown) that enables pressure control in the main body 1. The upper valve 3 is opened and closed by, for example, remote control using flood control. The upper valve 3 has a so-called air bleeding role of bleeding air inside the main body 1 by opening and closing as necessary when raising the pile 10 floating on the water. In the present embodiment, the role of bleeding air is performed by the upper valve 3 provided on the upper water stop plate 2. However, a hole may be provided in the main body 1 and the air in the main body 1 may be discharged from the hole.

The lower water stop plate 4 is removably arranged at the lower end of the main body 1. The lower water stop plate 4 seals the lower end of the hollow main body 1. The lower water stop plate 4 has, for example, a disk shape. The outer diameter of the lower water stop plate 4 is about the same as the inner diameter of the main body 1. The lower water stop plate 4 has a strength capable of withstanding the fluctuation of the internal pressure of the main body 1, and the detailed dimensions are appropriately determined. The lower water stop plate 4 is fitted inside the columnar main body 1. At that time, the gap between the main body and the main body 1 can be switched between sealing and opening by, for example, a mechanism using a hydraulic drive as a drive source.

By sealing the hollow main body 1 with the upper water stop plate 2 and the lower water stop plate 4, the pile 10 is made into a buoyant body capable of naturally floating on water. Further, the upper water stop plate 2 and the lower water stop plate 4 are removed from the main body 1 after the pile 10 floating on the water is vertically raised. The upper water stop plate 2 and the lower water stop plate 4 are detachably attached to the main body 1.

The lower valve (inflow port) 5 penetrates the lower water stop plate 4 in the vertical direction. The lower valve 5 is opened and closed by, for example, remote control using hydraulic pressure. The lower valve 5 has a role of allowing water to flow into the main body 1 or controlling the amount of inflow by opening and closing the pile 10 floating on the water as needed. The size of the lower valve 5 is set to be smaller than the outer diameter of the main body 1 so that water does not suddenly flow into the main body 1 when the lower valve 5 is released. ..

In the present embodiment, the work boat 20, the transport pontoon 21, the crane 30, the tugboat 40, the anti-rotation rope 50, the pile gripper 60, and the hydraulic hammer 70 are towed to the installation location and raised. Use.

As shown in FIG. 3, the pile 10 is towed by the transport carrier 21 to the installation location at sea. The transport carrier 21 has a size capable of transporting the above-mentioned pile 10. In FIG. 3, it is assumed that two piles 10 are loaded on the transport carrier 21 so that a plurality of piles 10 can be installed at one time. Alternatively, the towing line may be attached with the pile 10 floating on the sea, and the tugboat 40 may be towed to the construction site.

Further, the work boat 20 is for raising the pile 10 and has a crane 30. After being towed to the installation site by the transport carrier 21, the pile 10 is raised by using the crane 30 provided on the work vessel 20.

The crane 30 is used in the present embodiment when raising the pile 10. The crane 30 is a general jib crane in this embodiment. When raising the pile 10 by the crane 30, the hanging jig (not shown) provided on the water stop plate 2 on the upper side of the pile 10 is hung on the hanging hook (not shown) provided on the crane 30. Wake up.
Further, when the pile 10 before being raised from the transport carrier 21 is lowered, the crane 30 is lifted by attaching a horizontal holding wire (not shown) to the pile 10.

In the present embodiment, the crane 30 is installed on the stern portion of the work boat 20. Therefore, when the pile 10 is large, the weight of the pile 10 may exceed the crane capacity of the crane 30. In that case, it is supplemented by the buoyancy generated by floating the pile 10 on the water. Further, in such a case, the crane 30 cannot lower the pile 10 from the transport carrier 21. Therefore, the method of towing a pile 10 floating on the sea with a tugboat 40 as described above is preferably used.
Further, the height of the pile 10 may exceed the lift of the crane 30. In that case, when the pile 10 is raised, the lower end of the pile 10 is sunk to compensate. For example, when the pile 10 is lifted by the crane 30, it is conceivable that about 1/3 of the height of the pile 10 is sunk.

As shown in FIGS. 4 and 5, the tugboat 40 moves the pile 10 transported by the transport carrier 21 to a position where it can be raised by the crane 30. Further, when the pile 10 is raised by the crane 30, the tugboat 40 and the pile 10 are connected via the rotation prevention rope 50 to prevent the pile 10 from rotating in the axial direction.
The anti-rotation rope 50 connects the tugboat 40 and the stake 10. Examples of the anti-rotation rope 50 include a wire rope made of nylon and the like. The anti-rotation rope 50 is appropriately selected depending on the ease of transportation to the installation location, the ease of connecting the tugboat 40 and the pile 10, and the like.

As shown in FIG. 9, the pile gripper (gripper frame) 60 holds the pile 10 raised by the crane 30 when it is driven into the water bottom 100. The pile gripper 60 does not take charge of the vertical load of the pile 10, but serves as a guide for guiding the horizontal position of the pile 10. The pile gripper 60 is arranged at the base of the crane 30 on the work vessel 20. The pile gripper 60 horizontally sandwiches the pile 10 raised by the crane 30.

As shown in FIG. 10, the hydraulic hammer 70 is used when the pile 10 is vertically raised and then driven into the water bottom 100. As the hydraulic hammer 70, for example, S-3000 manufactured by IHC is used.

Next, the construction procedure in the present embodiment in which the pile 10 floating on the water is raised and placed on the bottom 100 will be described with reference to FIGS. 3 to 10.

First, as shown in FIG. 3, the transport vessel 21 towed to the installation location of the pile 10 is brought into contact with the stern portion of the work vessel 20. At this time, the transport pontoon 21 is brought alongside so that the traveling direction (longitudinal direction of the pile 10) is perpendicular to the traveling direction of the work vessel 20.
At this time, the center of gravity of the pile 10 is arranged within the working radius that can be lifted by the crane 30.
Further, since the pile 10 is used as a buoyant body as described later, the upper water stop plate 2 and the lower water stop plate 4 are incorporated in the main body 1.

After that, the horizontal holding wire is attached to the pile 10, and the horizontal holding wire is wound up by the crane 30 to lift the pile 10 vertically. After the pile 10 is completely separated from the transport vessel 21, the transport vessel 21 is ported from the work vessel 20. At this time, the longitudinal direction of the pile 10 and the traveling direction of the work boat 20 are at right angles.
After the transport vessel 21 has departed from the work vessel 20, the pile 10 is lowered from the crane 30 to float the pile 10 on the water.

As shown in FIG. 4, after the stake 10 is suspended on the water, the stake 10 is rotated by 90 ° by the tugboat 40 as shown in FIG. For example, when the pile 10 is viewed from above, it is swiveled so as to be centered on the center of the pile 10 in the longitudinal direction.
By doing so, the pile 10 is moved so that the upper water stop plate 2 is directly below the hanging hook of the crane 30. At this time, either before or after the rotation of the pile 10, the hanging jig of the upper water stop plate 2 and the hanging hook of the crane 30 are connected.

After that, before the pile 10 is raised by the crane 30, the tugboat 40 and the pile 10 are connected by the anti-rotation rope 50 as shown in FIG. This prevents the pile 10 from rotating in the axial direction during the raising work of the pile 10.

After that, as shown in FIG. 6, the hanging hook of the crane 30 is wound up, and the hanging jig provided on the upper water stop plate 2 is lifted to start the raising of the pile 10. At this time, the upper valve 3 and the lower valve 5 are not opened. That is, the inside of the pile 10 remains sealed. Further, when the pile 10 is raised, a sufficient working radius of the crane 30 is secured so that the work boat 20 and the crane 30 and the pile 10 do not come into contact with each other even if the pile 10 is shaken.
At this time, as shown in FIG. 6, the upper end and the upper water stop plate 2 of the pile 10 are in a state of being lifted by the crane 30. Further, the height of the pile 10 decreases from the upper water stop plate 2 toward the lower side of the pile 10. Then, the lower end of the pile 10 and the lower water stop plate 4 are submerged in the water 101.

While the inside of the pile 10 is sealed, the upper water stop plate 2 is wound up to a predetermined height by the crane 30. The height determined in advance includes conditions such as the angle of the pile 10 when the hanging hook of the crane 30 is wound up, the load of the pile 10 acting on the crane 30, the water depth of the installation location, the capacity and lift of the crane 30, and the like. Determined by analysis, taking into account the conditions. For example, in the present embodiment, the crane is wound up until the distance between the deck of the work boat 20 and the hanging hook of the crane 30 is 64 m.

After that, as shown in FIG. 7, the lower valve 5 is opened to allow water 102 to flow into the main body 1. At the same time, the valve 3 on the upper side is opened to exhaust the air inside the main body 1. At this time, when the water 102 flows vigorously into the inside of the pile 10 and the pile 10 suddenly sinks, a shocking load is generated on the crane 30. To prevent this from happening, the opening and closing of the upper valve 3 and the lower valve 5 is controlled as necessary. By this operation, it gradually flows into the main body 1 and gradually sinks.

Here, when a failure of the crane 30 or a sudden deterioration of the weather occurs during the construction of the pile 10, it may be necessary to interrupt or redo the water injection process. In this case, the construction work may be interrupted and redone by press-fitting air into the main body 1 and discharging water 102 from the lower valve 5.

The amount of water 102 flowing into the main body 1 is the minimum amount required for the pile 10 to be vertical as shown in FIG. For example, in the present embodiment, the water surface difference between the inside and the outside of the main body 1 when the pile 10 is vertical is set to 7 m. In the present embodiment, the amount of water injected up to this state is about 1200 m ³ . This leaves buoyancy on the pile 10 and facilitates the next work.
Further, the amount of water 102 flowing into the main body 1 is managed by the load of the pile 10 acting on the crane 30 and the posture of the pile 10 based on the result obtained by the analysis in advance.
After the pile 10 becomes vertical, the upper valve 3 and the lower valve 5 are closed to stop the inflow of water 102. After that, the anti-rotation rope 50 connected to the stake 10 is removed.

After that, as shown in FIGS. 9 and 10, the arm of the crane 30 is raised while controlling the height of the suspension hook of the crane 30 so as not to change. As a result, the pile 10 is pulled toward the work boat 20 side, and the pile 10 is sandwiched between the pile grippers 60. At this time, by applying buoyancy to the pile 10 as described above, the apparent weight of the pile 10 acting on the crane 30 is reduced. As a result, the working radius is set to secure a safe separation between the crane 30 and the pile 10, and even if the sea image suddenly changes, it is possible to safely stand by until the sea image settles down. Therefore, the pile 10 can be safely pulled.

After sandwiching the pile 10 between the pile grippers 60, the pile grippers 60 are closed. After that, the upper valve 3 and the lower valve 5 are opened again, and the water 102 is allowed to flow in until the water surface difference between the inside and the outside of the main body 1 disappears.
After that, the lower water stop plate 4 and the upper water stop plate 2 are removed from the main body 1 and collected. After the collection of both water stop plates is completed, the hanging hook of the crane 30 is lowered and the pile 10 is scuttled to the bottom 100.

After that, as shown in FIG. 10, the pile 10 is driven into the water bottom 100. The pile 10 is driven by installing the hydraulic hammer 70 on the crane 30. At that time, a sound level meter is installed if necessary.
After driving the pile 10 to the design depth, the hydraulic hammer is recovered.

As described above, according to the construction method of the present embodiment, the valve 5 having a diameter smaller than that of the main body 1 is provided at the lower end of the pile 10. As a result, the pile 10 is loosened by relaxing the upright speed at the initial stage of water injection into the pile 10 as compared with the case where the lower valve 5 is not provided on the pile 10 and the entire diameter of the pile 10 is opened. Can be raised in. Further, by gently raising the pile 10, for example, it is possible to reduce the inertial force when aligning the pile 10 after raising it with the driving position. Therefore, for example, it is possible to prevent an impact load from acting on the crane 30 when the pile 10 is raised. Further, when raising the stake 10, for example, the apparent weight of the stake 10 with respect to the crane 30 can be reduced. As a result, when the crane 30 raises the pile 10, the load on the pile 10 on the crane 30 can be minimized. That is, it is possible to provide a construction method capable of controlling the load of the pile 10 when raising the pile 10 and realizing a safe raising.

Further, the lower valve 5 is opened and closed by an external operation. As a result, the amount of water 102 flowing into the pile 10 can be controlled at any time. As a result, the load transmitted from the pile 10 to the crane 30 can be controlled more efficiently, and a safe upright can be realized.

Further, air is discharged from the main body 1 while water 102 is flowing in from the lower valve 5. Here, discharging the air from the main body 1 includes providing a hole in the main body 1 and discharging the air from the main body 1 through the hole, and the upper side provided separately from the main body 1 is provided. It also includes discharging the air of the main body 1 from the valve 3 or the like on the upper side of the water stop plate 2. Therefore, for example, as compared with the method of not discharging the air from the main body 1, it is not necessary to let the air escape from the lower valve 5, and the water 102 can flow into the pile 10 more efficiently.

Further, in a state where the pile 10 is vertically raised, the inflow amount of the water 102 from the lower valve 5 is controlled so that the water level of the water 102 inside the pile 10 is lower than the water level of the outside water 101. That is, the pile 10 in this state has buoyancy by the difference between the water surface between the outside and the inside. As a result, as compared with the case where the water surface of the water 102 inside the pile 10 and the water surface of the water 101 outside are the same, the load of the pile 10 acting on the crane 30 that pulls up the pile 10 when the pile 10 is raised (pile 10). The apparent weight of) can be reduced by the amount of buoyancy. Therefore, the load on the crane 30 when lifting the pile 10 can be reduced.
Further, the load of the pile 10 acting on the crane 30 is reduced, so that the capacity of the crane 30 can be increased. Therefore, the boom of the crane 30 can be tilted at the time of lifting. Therefore, the working radius of the crane 30 at the time of raising can be extended, and the distance between the crane boom and the pile 10 can be increased. As a result, the safe distance between the crane boom and the pile 10 is expanded, and even if the pile 10 is tilted or approaches the work boat 20 side due to inertial force immediately after the completion of raising the pile 10, the pile 10 and the work boat 20 or It is possible to avoid contact with the crane 30.

Further, after the water injection process is completed, the lower water stop plate 4 is removed from the pile 10. That is, after the alignment step, the water injection into the pile 10 is restarted, and after the water injection is completed, the lower water stop plate 4 is removed from the main body 1. As a result, when the pile 10 is aligned, the capacity of the crane 30 can be increased.

Further, before the process of removing the lower water stop plate 4, the pile 10 is hung from the bottom of the water. That is, when the pile 10 is suspended from the bottom of the water, the air inside the pile 10 is not evacuated by not removing the lower water blocking plate 4, and the pile 10 is suspended from the bottom while maintaining the buoyancy of the pile 10. Thereby, for example, even when the capacity of the crane 30 is insufficient with respect to the weight of the pile 10, the pile 10 can be suspended to the bottom of the water by utilizing the buoyancy.

Further, the water injection process is started when the first marking 6a (water injection start marking) overlaps the water surface of the water 101. Thereby, the timing of the start of the inflow of the water 102 can be easily visually determined.

Further, it is determined whether or not the water injection process can be started based on the positional relationship between the first marking 6a (water injection possibility determination marking) and the water surface of the water 102. As a result, for example, when it becomes difficult to continue the lifting process of the pile 10 due to a failure of the crane 30 during the lifting process of the pile 10, water injection is started without reaching the planned lifting height. Even so, it is possible to easily visually determine whether the capacity of the crane 30 is not exceeded and whether the pile 10 can be raised without contacting the bottom 100.

It also includes a step of lifting the upper end of the pile 10 with a crane 30. As a result, the lower end of the pile 10 can be positively submerged under the surface of the water 101. Therefore, the water 102 can flow into the pile 10 more efficiently.

Further, the behavior of the pile 10 is controlled by controlling the amount of water injected into the pile 10 according to the load of the crane 30. As a result, the state of the pile 10 can be managed more precisely. That is, the pile 10 can be erected more safely.

Further, during the water injection process, when the pile 10 is vertically raised, the water injection is interrupted once, and the crane 30 is raised to adjust the position of the pile 10 to a predetermined driving position. That is, in the water injection process, the crane 30 is used to raise the pile 10 vertically. After that, the lower valve 5 is closed to interrupt the water injection work. After that, the crane 30 is raised and the position of the pile 10 is adjusted to a predetermined driving position. After that, water injection into the pile 10 is restarted.
This makes it possible to maintain the buoyancy acting on the pile 10 during the alignment process. That is, the capacity of the crane 30 can be increased. Therefore, even when a dynamic load acts on the crane 30 due to the shaking of the pile 10 due to wind, tidal current, etc., the work can be safely performed without exceeding the capacity of the crane 30.
Further, even if the pile 10 is shaken by the wind and the tidal current when aligning the pile 10, it is possible to wait until the shaking is settled while ensuring a sufficiently safe separation between the work boat 20 and the pile 10. can. As a result, the pile 10 can be safely aligned without the pile 10 coming into contact with the peripheral equipment.

Further, when the height of the pile 10 lifted by the crane 30 reaches the lift of the crane 30, the water injection process is started. That is, by lifting the upper part of the pile 10 to some extent before the water 102 flows into the pile 10, the lower part of the pile 10 is in a state of being sunk below the water surface of the water 101. By starting the inflow from such a state, the water pressure applied to the lower valve 5 can be increased as compared with the case where the water injection is started before the upper part of the pile 10 is lifted. That is, the flow rate flowing from the lower valve 5 of the same size can be increased. Therefore, the water 102 can flow into the pile 10 in a shorter time.

Further, the pile 10 having a mass exceeding the rated load of the crane 30 is lifted by using the buoyancy acting on the pile 10. As a result, even when the performance of the crane 30 that can be used on the water is limited, the pile 10 can be raised by the crane 30. Therefore, the performance required for the crane 30 is lower than that when the buoyancy acting on the pile 10 is not used, the safety during construction can be improved, and the cost required for construction can be further reduced.

Further, a pile 10 having a length exceeding the lift of the crane 30 is raised by submerging the lower part of the pile 10 in water 101. As a result, even when the performance of the crane 30 that can be used on the water is limited, the pile 10 can be raised by the crane 30. Therefore, the performance required for the crane 30 is lower than that when the buoyancy acting on the pile 10 is not used, the safety during construction can be improved, and the cost required for construction can be further reduced.

It also includes a drainage step in which air is press-fitted into the main body 1 and water 102 is discharged from the lower valve 5.
Here, when a failure of the crane 30 or a sudden deterioration of the weather occurs during the construction of the pile 10, it may be necessary to interrupt or redo the water injection process. At this time, air is press-fitted into the main body 1 and water 102 is discharged from the lower valve 5. As a result, the construction work can be interrupted and redone as necessary. Therefore, the safety of the construction work can be further improved.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, as shown in FIG. 11, the marking 6 may be provided on the main body 1 for the purpose of controlling the angle when the pile 10 is raised.
Here, in the first marking 6a shown in FIG. 11, when the first marking 6a coincides with the water surface, the lower valve 5 and the upper valve 3 are opened to start the inflow of water 102 into the main body 1. (Water injection start marking).
Further, the second marking 6b means that the pile 10 comes into contact with the water bottom 100 when water is injected when the water surface of the water 101 is above the second marking 6b.

The position of the marking 6 is determined by prior analysis and is applied at the time of manufacturing the pile 10 or before shipping from the shipping quay. That is, the marking position varies depending on the size of the pile 10.
By providing the marking 6 in this way, it is possible to visually determine whether or not the inflow of water 102 into the main body 1 is started during the construction work of the pile 10. Further, when the marking 6 is not provided, the angle of the pile 10, the load acting on the crane 30, and the height of the pile 10 can be used as a substitute for the discrimination, but it is difficult to visually discriminate. That is, when the marking 6 is provided, the construction work can be facilitated as compared with the case where the marking 6 is not provided.

Here, during the lifting process of the pile 10, it may be difficult to continue the lifting process of the pile 10 due to a failure of the crane 30 or the like. As a countermeasure, even if water injection is started without reaching the planned lifting height of the first marking 6a, the capacity of the crane 30 is not exceeded and the pile 10 stands up without contacting the bottom 100. It may be used to judge whether or not the positional relationship can be raised (water injection propriety judgment marking).

Further, as shown in FIG. 12, when raising the pile 10, an inclinometer 80 may be attached to the main body 1 in order to control the angle of the pile 10. As a result, it is possible to more accurately grasp the angle during the raising of the pile 10 as compared with the case where the inclinometer 80 is not provided.

Further, as shown in FIG. 12, a remote control device 90 such as a ROV (remotely operated vehicle) may monitor the inclinometer 80 or open / close the lower valve 5. As a result, the situation of the underwater construction site can be grasped more accurately by the image as compared with the case where the remote control device 90 is not used. Further, if any problem occurs around the lower valve 5, it can be dealt with more quickly.

Further, in the present embodiment, after the vertical pile 10 is sandwiched between the pile grippers 60, the upper valve 3 and the lower valve 5 are opened so that the water surface in the main body 1 is at the same height as the outer water surface. Although it has been explained that the water 102 is allowed to flow in until the pile 10 becomes The water stop plate 4 may be removed.

Further, in the present embodiment, the inflow amount of water 102 from the lower valve 5 is controlled so that the water surface inside the main body 1 of the pile 10 is lower than the outside water surface in a state where the pile 10 is vertically raised. Described to do. However, without performing the above-mentioned control, the water surface inside the pile 10 main body 1 may be at the same height as the outside water surface at the same time as the pile 10 becomes vertical.
As a result, the labor required for the work can be omitted as compared with the case where the inflow amount of the water 102 is controlled.

Further, in the present embodiment, it is described that the crane 30 is used to raise the pile 10 and the inflow amount of the water 102 from the lower valve 5 is controlled by the load acting on the crane 30 and the posture of the pile 10. .. However, the amount of water 102 flowing into the pile 10 does not have to be based on the above method. For example, a flow meter may be provided near the valve 5 on the lower side. This makes it possible to more accurately grasp the amount of water 102 that has flowed in as compared with the case where the load acting on the crane 30 and the posture of the pile 10 are used for control.

Further, in the present embodiment, the water blocking plates 2 and 4 are provided on the main body 1 of the pile 10 before the pile 10 is raised, and the water stopping plates 2 and 4 are removed from the main body 1 after the pile 10 is raised. Described doing the work. However, if the driving of the pile 10 is not affected, the water blocking plate 2 may be scuttled as it is without being removed. This enables the scuttling work with the crane 30 having a lower capacity as compared with the case where the water blocking plates 2 and 4 are removed.

Further, in the present embodiment, the crane 30 is used to erect the pile 10, and when the height of the pile 10 reaches the lift of the crane 30 in the process of erecting the pile 10, water from the lower valve 5 is used. It is described that the inflow of 102 is started. However, the inflow of water 102 may be performed at the same time as the work of lifting the pile 10 by the crane 30 as long as the crane capacity is sufficient for the impact load acting when the pile 10 is raised. As a result, the time required for the work can be shortened as compared with the case where the inflow of the water 102 is started after reaching the lift of the crane 30.

Further, in the present embodiment, whether or not the crane 30 is used to raise the pile 10 and the inflow of water 102 from the lower valve 5 is started based on the load acting on the crane 30 and the height of the pile 10. It was described to determine whether or not. However, it is not necessary to use the above-mentioned method for determining whether or not to start the inflow of water 102. For example, a water pressure gauge or an inclinometer near the valve 5 on the lower side of the pile 10 may be attached, and it may be determined whether or not the inflow of the water 102 is started based on the information. As a result, the start of the inflow of the water 102 is determined more accurately than the case of determining whether or not the inflow of the water 102 is started based on the load acting on the crane 30 and the height of the pile 10. It can be carried out.

Further, in the present embodiment, it is described that the crane 30 is used to raise the pile 10 and the pile 10 having a weight close to the rated load of the crane 30 is raised and lifted by using buoyancy. That is, it is assumed that the rated load of the crane 30 may be exceeded when the inertial force acting on the pile is taken into consideration in the work such as raising the pile. However, a similar process may be used for the relatively small diameter pile 10. As a result, even if a crane 30 having a sufficient crane capacity is not prepared, a small crane 30 having a minimum necessary crane capacity can be used, and the crane 30 can be arranged and prepared at less cost. Can be done.

Further, in the present embodiment, it is described that the crane 30 is used to erect the pile 10 and the pile 10 having a length exceeding the lift of the crane 30 is erected by submerging the lower part of the pile 10 in water. That is, it is assumed that the long pile 10 exceeds the lift of the crane 30. However, a similar process may be used for the relatively short pile 10. As a result, even if a crane 30 having a sufficient lift is not prepared, it is possible to construct the crane 30 by using a small crane 30 having a minimum necessary lift at less cost in arranging and preparing the crane 30. ..

In addition, it is possible to replace the components in the embodiment with well-known components as appropriate without departing from the spirit of the present invention, and the above-mentioned modifications may be appropriately combined.

1 Main body 2 Upper water stop plate 3 Upper valve 4 Lower water stop plate 5 Lower valve 10 Pile 30 Crane 100 Water bottom 101 Water

Claims (11)

The hollow main body, the lower water stop plate arranged at the lower end of the main body and sealing the lower end of the main body, and the upper end of the main body arranged at the upper end of the main body and sealing the upper end of the main body are sealed. An upper water stop plate that seals the inside of the water stop plate between the lower water stop plate and a lower valve that is provided on the lower water stop plate and has a diameter smaller than that of the main body. It is a method of constructing a pile in which a pile having an upper valve provided on the upper water stop plate and a pile having the upper valve is raised and placed on the bottom of the water.
A lifting process in which the upper end of the pile lying on the water with the inside of the pile sealed without opening the inflow port and the valve on the upper side is lifted by a crane.
By carrying out the lifting step, while the lower end of the pile and the lower water stop plate are submerged in water, the inflow port is opened and water is allowed to flow into the main body through the inflow port. , A water injection step of opening the upper valve and discharging air from the main body through the upper valve .
After the water injection step, the pile is driven into the water bottom with the lower water stop plate and the upper water stop plate removed from the main body .
Pile construction method. In the lifting step, the pile having a mass exceeding the rated load of the crane is lifted by using buoyancy.
The pile construction method according to claim 1. In the water injection step, the inflow amount of water from the inflow port is controlled so that the water surface inside the pile is lower than the water surface outside while the pile is vertically raised.
The pile construction method according to claim 1 or 2. The inflow port is opened and closed by an external operation.
The pile construction method according to any one of claims 1 to 3. A water injection start marking is provided on the main body of the pile, and the water injection step is started when the water injection start marking overlaps the water surface.
The pile construction method according to any one of claims 1 to 4. A water injection propriety determination marking is provided on the main body of the pile, and whether or not the water injection process can be started is determined based on the positional relationship between the water injection feasibility determination marking and the water surface.
The pile construction method according to any one of claims 1 to 5. In the water injection step, the behavior of the pile is controlled by opening and closing the inflow port and the valve on the upper side according to the load of the crane to control the amount of water injected into the pile.
The pile construction method according to any one of claims 1 to 6. In the middle of the water injection process, the water injection is interrupted once when the pile is vertically raised, and the position of the pile is adjusted to a predetermined driving position by raising the crane.
The pile construction method according to any one of claims 1 to 7. In the lifting step, when the height of the pile reaches the lift of the crane, the water injection step is started.
The pile construction method according to any one of claims 1 to 8. In the water injection step, the pile having a length exceeding the lift of the crane is raised by submerging the lower part of the pile in water.
The pile construction method according to any one of claims 1 to 9. After the water injection step, the drainage step of injecting air into the main body and discharging water from the inflow port is included.
The pile construction method according to any one of claims 1 to 10.

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