JP3954675B2 - Caisson and method of moving caisson - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a caisson and a method of moving the caisson, and more particularly, a caisson used as a breakwater or a seawall, in which a part of the weight for stabilizing against waves is provided by the filling sand, The present invention relates to a method of moving after installation.
[0002]
[Prior art]
A general breakwater caisson is made of a box-shaped caisson enclosure that is open only on the top, transported to the site, and then filled with sand inside the enclosure. By placing, a stable weight is applied to the waves and installed.
[0003]
In addition, there was no need to move the breakwater caisson once installed, but in recent development plans for large offshore oil storage bases, etc. It has become desirable to use a caisson in which the breakwater to be moved is moved by a crane ship or the like and then installed again.
[0004]
[Problems to be solved]
However, once the conventional breakwater caisson is moved by a crane ship after installation, the padding sand must be removed to reduce the weight, but in this case, the upper concrete may be demolished or re-installed at the time of re-installation. Concrete has to be laid, which makes the work very cumbersome.
[0005]
The present invention has been made in view of the above points, and an object of the present invention is to provide a caisson that can be easily moved and re-installed once installed, and a method of moving the caisson. .
[0006]
[Means for Solving the Problems]
The caisson according to the present invention is a caisson in which medium-filled sand that secures a stable weight against waves is packed inside , and the cover that can be removed and attached to remove the medium-filled sand and move the caisson. Is provided in the upper concrete of the caisson .
[0007]
That is, in the case of this caisson (first caisson), when it is moved after it has been installed once, the lid is removed, the padding sand is removed, and the weight is reduced to facilitate the movement by a hoist ship or the like. In addition, re-installation can be easily performed by attaching a lid after refilling the filling sand.
[0008]
As the lid, if the caisson is relatively small, it may be possible to remove the entire part corresponding to the upper concrete, but the breakwater caisson is generally large. It is possible to divide each into a cover, or to provide an appropriate number of openings in the upper concrete and to provide a cover in each opening. In addition, when passing a vehicle etc. on the upper construction, it is desirable to provide a minimum necessary opening for strength and to install a lid in this opening. Further, the inside of a normal caisson is partitioned into a plurality of chambers by partition walls, and each chamber is filled with filled sand, so it is desirable to set an opening or the like so that the filled sand can be removed from each chamber. .
[0009]
As an example of the installation of the lid, a concrete example may be given in which the concrete is filled or bolted. If there is no problem in strength, the upper work body and the lid may not be connected, and a groove or the like may be formed around the opening to fit the lid.
[0010]
This makes it easier to remove and install the lid.
[0011]
As a material of the lid on the premise of repeated use, for example, reinforced concrete (PC) can be preferably cited.
[0012]
Further, in this caisson, the Around the upper concrete, through holes for spraying water jets from the outside in order to correct the deviation of the packed sand in the caisson inside which occurs when packing again or remove the in packed sand it may be provided.
[0013]
This is because the side of each chamber in the caisson is as large as about 5 m. When removing the filling sand for movement or refilling the filling sand at the time of re-installation, the opening of the opening after the cover is removed. Depending on the position and size, there may be an imbalance in the height of the filling sand in one room. For example, in one room, discharging (or filling) of the filling sand proceeds near the opening, while discharging (or filling) stagnates in a portion far from the opening. Can be corrected by spouting. Such holes can be provided in the superstructure.
[0014]
It should be noted that the water injection through the holes can carry the role of making the discharge of the filled sand by a sand pump wet, for example.
[0015]
Another caisson according to the present invention is a caisson in which medium-filled sand that secures a stable weight against waves is stuffed inside and accommodates a block, in order to remove the block and move the caisson And a lid that can be removed and attached to the upper work of the caisson .
[0016]
That is, in the caisson, a part of the weight secured by the filling sand is replaced with one or a plurality of blocks, and the required weight is reduced by removing the blocks. In addition, since a block is easy to put in and take out compared with the filling sand, this caisson can be moved and re-installed more easily than the first caisson.
[0017]
Therefore, the total weight of one or a plurality of blocks used in this caisson is set so that the caisson weight including the filling sand is easily moved by a crane ship etc. In some cases, the required weight reduction may be achieved by removing some of the blocks.
[0018]
In addition, it is desirable that the height of the partition wall dividing the inside of the caisson into a plurality of chambers is lowered according to the reduced filling amount of the filling sand, and the block is accommodated in the upper space.
[0019]
Preferred examples of the block material include ordinary concrete and heavy concrete.
[0020]
The lid in this caisson is the same as the lid in the first caisson as long as the block can be removed.
And the moving method of the caisson according to the present invention is a method of moving the caisson after removing the filling sand after it is stuffed into the inside to secure a stable weight against the waves, and once installed, Removing the lid, spraying the padding sand with a water jet to remove the padding sand while correcting the offset of the padding sand, and lightening the caisson so that it can be moved; It consists of the process of installing after moving up after it floats.
Further, the caisson moving method according to the present invention is a method of moving the caisson after removing the block after stuffing the inside packed sand that secures a stable weight against the waves and accommodating the block inside. And the step of removing the lid, the step of removing the block to lighten the caisson so that it can be moved, and the step of moving the caisson after being lifted by a crane ship and then installing it. is there.
[0021]
【Example】
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0022]
FIG. 1 is a cross-sectional view schematically showing a state in which a caisson 10 according to the present invention is installed as a breakwater with a foundation mound (rubble) 2 interposed on a seabed ground 1, and FIG. 2 is a plan view of the caisson 10. is there.
[0023]
The caisson 10 is divided into four chambers 13 by way of example with a cross-shaped partition wall 12 and, when first installed, the superstructure 14 is constructed after filling each chamber 13 with the filled sand 3. Is done. The caisson housing except for the superstructure 14 is generally the same as the conventional one.
[0024]
The upper work 14 includes an upper concrete 15, a PC lid 19 that fits into an opening 16 set in the center of the upper concrete 15, and a parapet 18 that is attached to the overseas side of the upper concrete 15 as a reverse work. A plurality of through holes 17 are set around 15. In this example, since the vehicle or the like passes through the upper surface of the upper work 14, it is necessary to maintain the strength of the upper work 14 high, and the opening 16 is the minimum necessary to remove the filling sand 3 from each chamber 13. . Further, the opening 16 is provided so that a slight gap is formed between the opening 16 and the PC lid 19 in a state in which the PC lid 19 is fitted. It is firmly fixed. Moreover, it is also possible to raise the intensity | strength of the whole superstructure by inserting a reinforcing bar etc. in this padding part as needed. In addition, it is desirable that the PC lid 19 is supported by the partition wall 12 and that the through hole 17 is also normally closed so that there is no danger when going over the superstructure.
[0025]
In moving the caisson 10 once installed as described above, first the chipped concrete 20 is chipped and the PC lid 19 is removed. Next, as shown in FIG. 3, the sand pump 21 is sequentially inserted into the respective chambers 13 through the openings 16, and the caisson 10 can be easily removed by the crane ship 30 (see FIG. 4) by removing an appropriate amount of the sand filling 3. Make it light enough to move. At this time, it is necessary to introduce seawater in order to discharge the filled sand 3 by the sand pump 21 in a wet manner, and this is used as a caisson via a through-hole 17 by using a jet pump (not shown). It sprays on the filling sand 3 near the side wall 11 (see FIG. 3). This is because the middle sand 3 is discharged only near the opening 16 and the middle sand 3 near the side wall 11 is left behind, which may cause inconveniences such as poor balance when the caisson 10 is moved. This is to correct the misalignment by transporting the packed sand 3 near 11 to the center side.
[0026]
Thereafter, as shown in FIG. 4, the caisson 10 is levitated by the crane ship 30 through a suspension bar (not shown) buried in the upper concrete 15 and then moved by towing or the like. Depending on the shape and size of the caisson, the caisson itself may be lifted only by buoyancy. In this case, the caisson can be moved by pulling the caisson with a tugboat.
[0027]
In addition, when the caisson 10 is installed again, the filled sand 3 is introduced into each chamber 13 from the opening 16. In this case, the filled sand 3 is not deposited only near the opening 16. By appropriately ejecting a water jet through 17, it is possible to adjust so that the filled sand is reliably filled also in the vicinity of the side wall 11. Note that the reattachment of the PC lid 19 is the same as in the initial installation.
[0028]
Next, another caisson 10 ′ according to the present invention will be described with reference to FIGS. 5 to 7, but matters common to the caisson 10 include the same reference numerals, and description thereof will be omitted.
[0029]
The caisson 10 ′ is divided into a lower region in which the inside is filled with the filled sand 3 and an upper region in which a plurality of heavy concrete blocks 4 are stacked and accommodated. Further, the lower region is partitioned into four chambers 13 ′ by a cross-shaped partition wall 12 ′, while the upper region is provided with a convex portion 11 ″ extending in the vertical direction in order to limit horizontal sliding of the block 4. Accordingly, a gap is formed between the side walls 11 in a state where the block 4 is accommodated in the upper region.
[0030]
The superstructure 14 ′ is a PC lid 19 ′ that is precast except for the parapet 18 ′, and the PC lid 19 ′ is fixed to the caisson housing side by clogging concrete. Further, the PC lid 19 ′ is supported by the uppermost block 4 and the side walls 11 ′, and the upper portion of the overseas side wall 11 ′ is made thick to ensure the support of the PC lid 19 ′.
[0031]
The characteristic of the caisson 10 'is that a part of the weight secured by the filling sand 3 is borne by an appropriate number of blocks 4, and the total weight of the block 4 is eliminated by removing all of this. The weight of the caisson 10 ′ including the sand 3 is set so that it can be easily moved by the crane ship 30.
[0032]
Therefore, when moving the caisson 10 'once installed, first, the chipped concrete is chipped, the PC lid 19' is removed and the upper part of the caisson 10 'is opened, and then, as shown in FIG. After lifting and removing them one by one, the caisson 10 ′ is moved by the crane ship 30. Therefore, no sand pump or jet pump is required. The re-installation of the caisson 10 'is the reverse of the above process.
[0033]
【The invention's effect】
As described above, in the caisson according to the present invention (first caisson), the weight of the caisson can be reduced to an extent that can be easily moved by removing the lid and removing the filling sand. Once installed, the caisson can be easily moved, and in the case of re-installation, the same lid can be attached after refilling the filled sand.
[0034]
In another caisson according to the present invention, the same effect as that of the first caisson can be obtained by removing the cover from the block replaced with a part of the padded sand. Compared with the first caisson, the sand pump is unnecessary and it is not necessary to take into account the misalignment of the padded sand.
[Brief description of the drawings]
FIG. 1 is an explanatory sectional view schematically showing a state in which a caisson according to the present invention is installed as a breakwater.
FIG. 2 is a plan view of a caisson.
FIG. 3 is an explanatory view showing a state in which the filling sand is removed from the caisson.
FIG. 4 is an explanatory view showing a state in which a caisson is levitated by a crane ship.
FIG. 5 is a cross-sectional view showing a state in which another caisson according to the present invention is installed.
FIG. 6 is a plan view of another caisson.
FIG. 7 is an explanatory diagram showing a state in which a block is removed from another caisson.
[Explanation of symbols]
3 Filled sand 4 Block 10, 10 'Caisson 11, 11' Side wall 12, 12 'Partition 13, 13' Chamber 14, 14 'Upper work 15 Upper concrete 16 Opening 17 Through hole 18, 18' Parapet 19, 19 'PC Lid 20 Filled concrete 21 Sand pump 30 Crane ship

Claims (5)

 In a caisson filled with filling sand that secures a stable weight against waves, a lid that can be removed and attached to remove the filling sand and move the caisson is provided in the upper concrete of the caisson. A caisson characterized by the fact that it is provided in  In the periphery of the upper concrete, there is provided a through-hole for spraying a water jet from the outside in order to correct the offset of the internal sand in the caisson generated when the internal sand is removed or refilled. The caisson according to claim 1.  A caisson packed inside with sand filling the inside to secure a stable weight against waves and accommodating the block, the lid allowing removal and attachment to remove the block and move the caisson A caisson characterized in that a body is provided in the superstructure of the caisson. The caisson according to claim 1 is a method in which the caisson is filled with filling sand that secures a stable weight against waves , and after the installation, the caisson is moved after removing the filling sand. And
Removing the lid, spraying the padding sand with a water jet to remove the padding sand while correcting the offset of the padding sand, and lightening the caisson so that it can be moved; A caisson moving method comprising a step of installing after floating and then moving. Using the caisson according to claim 3, after the installation once housing the block with cram packed sand therein in securing the weight to stabilize against waves on the caisson, move the caisson after removing the block A way to
A caisson moving method comprising: a step of removing the lid, a step of removing the block to make the caisson light enough to move, and a step of moving the caisson after being lifted by a crane ship and then installing the caisson.

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