JP5685482B2 - Breakwater reinforcement method - Google Patents

Description

  The present invention relates to a method for reinforcing a caisson type breakwater.

  If a caisson-type existing breakwater (first-line breakwater) is damaged by an earthquake or tsunami, the breakwater cannot shield the harbor from waves, and a satisfactory port function cannot be secured. Therefore, it is time-consuming and costly to construct a new breakwater, even though it is necessary to improve the breakwater immediately.

  Therefore, as a provisional measure, it is customary to first restore the breakwater prototype by reusing the damaged caisson.

  However, simply performing the original restoration work may cause a similar disaster again.

  For this reason, it is necessary to build a breakwater that can cope with newly defined tsunami conditions (next predicted tsunami conditions) after the prototype restoration work is completed.

  By the way, as a method of reinforcing a caisson type breakwater, it is known to install and reinforce an asymmetrical extension caisson in a cross-sectional direction along the front wall or the back wall of the existing caisson type breakwater (for example, Patent Document 1).

JP 2008-190254 A

  In the technique described in Patent Document 1, an asymmetrical extension caisson is installed in the front-rear direction in cross section along the front wall or the back wall of the existing breakwater, so that the reinforcement that can cope with tsunami conditions higher than the height of the existing breakwater is Can not do it.

  The inventor conceived that if a gate-type caisson that covers the existing breakwater of the caisson type is used, the existing breakwater can be used to reinforce the existing breakwater so that it can cope with the high tsunami conditions of the existing breakwater. Invented.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a breakwater reinforcement method that can shorten and inexpensively reinforce an existing breakwater by using a gate-type caisson of a size that covers the existing breakwater.

The invention of claim 1 is a breakwater reinforcing method for increasing the height of a caisson-type existing breakwater, and a step of manufacturing a gate-type caisson having a size corresponding to the existing caisson constituting the existing breakwater; A step of installing the portal caisson so as to cover the existing breakwater, and a filling material between the portal caisson and the existing breakwater in a state where the portal caisson is installed so as to cover the existing breakwater And the step of integrating the portal caisson with the existing breakwater, the portal caisson has an upper side wall part and two front and rear side wall parts extending in parallel, the upper side wall part, said plurality of inlet is formed, the front and rear side wall portions are respectively a hollow structure, it is possible to fill the filling material between the gate-shaped caisson and the existing breakwater plurality Wherein the inlet is provided. Here, the size of the gate-type caisson is determined according to an ordinary caisson type breakwater design method, assuming that it is integral with the existing breakwater. The existing caisson (existing breakwater) includes caisson that has been restored to its original form following a disaster. Furthermore, to install so as to cover it means that it is in a state of being covered in the installed state.

  In this way, the portal caisson manufactured in the land work yard or the like is installed so as to cover the existing breakwater (existing caisson), and through the plurality of inlets of the portal caisson, the portal caisson and the By filling various fillers between the existing breakwater (existing caisson), they can be integrated and the breakwater can be reinforced. In particular, the portal caisson is installed so as to cover the existing breakwater, which is an advantageous reinforcement for increasing the height of the existing breakwater.

In addition, the appearance can be the same as when a new breakwater is constructed, and the appearance is not impaired.

According to a second aspect of the present invention, it is preferable that a reinforcing steel frame is bridged inside each of the input ports.

  If it does in this way, while ensuring required rigidity, the weight reduction of the portal caisson to perform additional construction can be achieved, and handling of the portal caisson becomes easy.

As described in claim 3, comprising the steps of providing a step of the also said plurality of inlet of the integrated portal caisson is filled with the filler, followed lid concrete covering the upper side wall portion, the lid concrete And a step of providing upper concrete (so-called superstructure) on the top.

  If it does in this way, the height of a breakwater can be made high, without giving a big change to an external appearance.

According to a fourth aspect of the present invention, the portal caisson is provided with a pipe for filling a water-stopping material between the lower part of the portal caisson and the existing breakwater in the front and rear side walls. It is desirable.

  If it does in this way, the water stop material can be easily filled between the lower part of the portal caisson and the existing caisson using the pipe.

The step of providing a lid member for closing a gap formed between the existing breakwater and the front and rear side wall portions of the portal caisson when the integration is further performed as in claim 5. Preferably, the lid member is provided with an insertion hole for inserting a pipe for filling the gap with the filler.

  If it does in this way, stable support of piping will be attained by a lid member, and filling work (for example, expanded concrete) to the crevice between the existing caisson and the front and back side wall parts of a portal caisson becomes easy. .

As described in claim 6, the gantry caissons, the water stopping material corresponding to the joints of the existing breakwater is arranged cylindrical filling bag is filled, the filling of the water stopping material to the filled bladder It is desirable to have a step of forming a water stop portion for preventing seawater from entering between the existing breakwater and the portal caisson.

  If it does in this way, the operation | work which forms the water stop part which prevents that seawater infiltrates between the said existing caisson and a portal caisson becomes easy using a cylindrical filling bag.

As described in claim 7 , it is desirable to have a step of providing outer walls extending toward the inner surface of the portal caisson to be installed on both sides in the width direction at the upper part of the existing breakwater.

  If it does in this way, it will prevent that the filler (for example, inside packing sand) between the upper part of the said existing caisson and the said portal caisson leaks outside by an outer wall.

By the way, when the portal caisson is large and heavy, as described in claim 8 , the portal caisson is inserted from a side of the existing breakwater and is moved and installed in a direction in which the breakwater extends. Therefore, it is preferable that a roller is provided for rolling the wall surface of the existing breakwater to restrict contact between the existing breakwater and the portal caisson.

  In this way, when the portal caisson is half-sunk, it is inserted from the side of the existing breakwater and moved in the direction in which the breakwater extends, and the portal caisson comes into contact with the existing breakwater and is damaged. Therefore, even if the portal caisson is large, it can be installed in a state where it is finally covered with the existing breakwater.

  Since this invention is comprised as mentioned above, the reinforcement construction which makes the height of an existing breakwater high can be performed in a short time and cheaply by utilizing the gate-type caisson which covers the existing breakwater.

It is a schematic explanatory drawing which shows the state after reinforcing the existing breakwater (existing caisson) which concerns on this invention with the portal caisson. It is sectional drawing in the AA of FIG. It is a perspective view which shows a portal type caisson. It is a perspective view which shows the relationship between a portal type caisson and an existing caisson. It is explanatory drawing of the existing caisson restoration (step 1). It is explanatory drawing of a gate caisson installation preparation (step 2). It is explanatory drawing of a gate type caisson installation (step 3). It is explanatory drawing of conveyance of a portal caisson. FIGS. 9A to 9E are explanatory diagrams of the existing caisson / gate caisson integrated preparation work (step 4). 10A to 10E are explanatory diagrams of the existing caisson / gate caisson integrated preparation work (step 4), respectively. FIGS. 11A and 11B are explanatory diagrams of the existing caisson / gate caisson integration operation (step 5), respectively. It is explanatory drawing of a filling sand filling (step 6). It is explanatory drawing of cover concrete placement (step 7). It is explanatory drawing of a still water grout filling bag top end part cutting removal (step 8). It is explanatory drawing of upper concrete placement (step 9). It is explanatory drawing which shows other embodiment of a portal caisson. It is explanatory drawing which shows another embodiment of a portal caisson.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the direction in which the existing caisson 2 is installed (the direction in which the breakwater extends) will be described as the left-right direction (width direction), the sea (open ocean) side as the front side, and the land side as the rear side.

  1 is a schematic explanatory view showing a state after an existing breakwater (existing caisson) according to the present invention is reinforced with a portal caisson, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG. 3 is a portal caisson FIG. 4 is a perspective view showing the relationship between the portal caisson and the existing caisson.

  As shown in FIGS. 1 to 4, the breakwater reinforcing method according to the present invention covers the existing caisson 2 (or the restored caisson) constituting the existing breakwater 1 with the portal caisson 3, and the breakwater height is already set. The reinforced breakwater 4 is higher than the breakwater 1.

  Each existing caisson 2 has a footing 2a protruding in the front-rear direction in order to stabilize in the front-rear direction, and is installed on a rubble mound 5 whose upper surface is leveled. In accordance with the size of the portal caisson 3 for reinforcement, the rubble mound 5 is reinforced by the reinforcing mound 5A so that the front and back of the rubble mound 5B before reinforcement by the portal caisson 3 are reinforced.

  The portal caisson 3 has a rectangular upper wall portion 3A having a width substantially equal to that of the existing caisson 2 in the left-right direction and longer than the existing caisson 2 in the front-rear direction, and parallel vertically downward from both front and rear edges of the upper wall portion 3A. It has front and rear side wall portions 3B, 3C and has a gate shape. The portal caisson 3 is basically an RC structure, and has a predetermined height to ensure necessary rigidity. Step portions 3Ba and 3Ca into which the footing 2a is fitted are formed at the lower ends of the front and rear side wall portions 3B and 3C.

  Expanded concrete 6 (filler) is filled between the existing caisson 2 and the front and rear side wall portions 3B, 3C, and filled sand 7 (filler) is filled between the existing caisson 2 and the upper wall portion 3A. The existing caisson 2 and the portal caisson 3 are integrated.

  On the upper side of the portal caisson 3, an upper concrete 12 (so-called upper work) having a convex portion 12a on the sea side is provided with a lid concrete 11 in between.

  The upper side wall 3A is formed with a plurality of hollow inlets 3Aa (partition chambers) penetrating in the vertical direction, and each inlet 3Aa is rectangular when viewed from above and is reinforced in the diagonal direction. The steel frame 13 is provided so as to be bridged. Thereby, both weight reduction and ensuring of the construction space of various fillers, such as expansion concrete 6 and filling sand 7, are achieved. The front and rear side wall portions 3B, 3C are formed with a plurality of hollow portions 3Bb, 3Cb extending in the vertical direction and having bottom portions for weight reduction, respectively, and are installed inside the hollow portions 3Bb, 3Cb, Filled sand 7 is filled. The filling port 7Aa is also filled with the filled sand 7 after installation.

  The clearance between the existing caisson 2 and the portal caisson 3 installed on the outside is determined in consideration of the construction accuracy when installing the portal caisson 3 and the fitting of the existing caisson 2 with the footing 2a. Is done. That is, a gap is formed between the existing caisson 2 and the gate-type caisson 3 in a state where the existing caisson 2 is covered, and the gap is usually about 50 cm, for example.

  In order for the expanded concrete 6 (filler) to be in close contact with both the caissons 2 and 3 and to obtain sufficient strength, it is necessary to harden them in a tightly sealed and constrained state, so the existing caisson 2 and the portal caisson 3 The bottom part and the side part of the gap between the two are sealed by using a grout material 14 (water-stopping material) or the like so that water does not enter (see FIG. 2). The expanded concrete 6 has a compressive strength comparable to that of the caissons 2 and 3.

Next, the construction procedure of the portal caisson 3 will be described in detail.
Step 1: Restoring the existing caisson If the existing caisson is damaged, first, the original caisson 2 of the original shape is installed by the original restoration work (see FIG. 5). Note that the rubble mound 5 is reinforced by the reinforcing mound 5A in accordance with the size of the portal caisson 3, and the mound surface is leveled. In addition, a basic rubble is 200-400 kg / piece, for example.
Step 2: Preparation before installation of portal caisson As shown in FIG. 6, seawater is placed on the upper side of the footing 2 a of the existing caisson 2 (the portion that becomes the support portion of the portal caisson 3 and the stepped portions 3Ba and 3Ca are fitted). A sheet-like water-stopping material 21 is set to prevent the intrusion of water and a plate-like outer wall 22 for restraining the material to be filled between the existing caisson 2 and the portal caisson 3 so as not to leak outside. As shown in FIG. 6, it is constructed on both sides in the width direction so as to extend toward the inner surface (or lower surface) of the portal caisson 3 so as to extend slightly upward above the existing caisson 2.

At this time, after installing the portal caisson 3, as shown in FIGS. 7 and 9A and 9B, a gap S is formed between the upper edge of the outer wall 22 and the portal caisson 3. The outer wall 22 is constructed with a certain height in advance.
・ Step 3: Manufacture of portal caisson ・ Installation of portal caisson Then, as shown in FIG. 7, install the portal caisson 3 from the upper side to the existing caisson 2 (existing breakwater 1) through the outer wall 22. .

  This portal caisson 3 is manufactured in a land work yard with a size corresponding to the existing caisson 2, that is, a size that can cover the existing caisson 2 of the existing breakwater 1. Therefore, the size of the portal caisson 3 differs depending on the existing caisson 2 (existing breakwater 1).

After this production, as shown in FIG. 8, the portal caisson 3 is transported by using, for example, a crane ship 23, and the portal caisson 3 is suspended from the sky above the existing breakwater 1 so as to be placed on the existing caisson 2. It will be. After installation of the portal caisson 3, a gap S is formed between the top end of the outer wall 22 and the lower surface of the portal caisson 3.
Step 4: Integration preparation work of existing caisson and portal caisson First, a gap formed between the top end of the outer wall 22 and the inner surface of the portal caisson 3 is filled. Thereby, when the filling sand 7 is filled, it does not leak to the outside.

  After installing the gate-type caisson 3, as shown in FIG. Specifically, as shown in FIG. 9C, the placing procedure of the bottom water-stopping concrete 24 is embedded in advance in the front and rear side wall portions 3B and 3C of the portal caisson 3 so as to extend from the lower end to the top end. An embedded pipe 25 of a concrete plant ship (not shown) is connected to the embedded pipe 25 (existing installed pipe) near the top, and through the embedded pipe 25, as shown in FIG. A bottom water-stopping concrete 24 (water-stopping material) is placed on the water material 21. The embedded pipe 25 is mounted in advance in each of the hollow portions 3Bb and 3Cb using a mounting bracket (not shown) so that the lower end penetrates the bottom (see FIG. 9D). It is possible to fill the predetermined portion with the bottom water-stopping concrete 24 without difficulty.

  Then, as shown in FIG. 9 (e), a restraining lid 27 (made of L-shaped steel) as a lid member is attached with bolts 28. That is, the horizontal part of the restraining lid 27 is fixed to the upper part of the existing caisson 2, and the vertical part is fixed to the inner wall surfaces of the front and rear side wall parts 3B and 3C of the portal caisson 3, respectively. A plurality of insertion holes 27a are formed in the restraining lid 27 in the width direction, and a placement pipe 29 of a concrete plant ship (not shown) is inserted into the insertion holes 27a so as to be movable up and down.

Furthermore, as shown in FIGS. 10 (a), (b), and (c), a cylindrical filling bag 32 of still water grout having a grout material 31 (water stop material) and a filling hole 32a is attached to the joint portion 33, A water stop grout 31 is driven through the filling bag 32. As a result, as shown in FIG. 10 (d), a water stop portion is formed between the portal caisson 3 and the existing caisson 2 by the grout material 31 filled in the filling bag 32, and the sea water 34 is present. And the expanded concrete 6 are cut off, so that the seawater is prevented from entering between the existing caisson 2 and the portal caisson 3. The filling bag 32 is left after the construction together with the grout material 31 except for the protruding portion 32b which is the top end (see FIG. 14).
Step 5: Integration work of existing caisson and portal caisson After the joint construction described above, the expanded concrete 6 is placed through the placement pipe 29 as shown in FIG. That is, the casting pipe 29 is inserted into the insertion hole 27a of the restraining lid 27, and the casting concrete 29 is gradually lowered from the bottom side while the casting pipe 29 is sequentially pulled up from the bottom side while the casting pipe 29 is lowered to the lowest position. Go to fill. In addition, as expansion concrete 6, underwater non-separable expansion concrete is used, and a filling condition is managed with the pressure gauge installed in the side part.

Thereby, as shown in FIG. 11 (b) when viewed from above, the expanded concrete 6 is filled between the existing caisson 2 and the portal caisson 3, and the bottom water-stopping concrete 24 is positioned outside thereof. Become.
Step 6: Filling with filling sand As shown in FIG. 12, the space between the upper part of the existing caisson 2 and the portal caisson 3, the hollow parts 3Bb and 3Cb of the front and rear side wall parts 3B and 3C and the inlet 3Aa, Fill the padding sand 7.
Step 7: Placing the lid concrete After filling the sand stuffing 7 and eliminating the void portion, the lid concrete 11 is constructed on the upper side of the portal caisson 3 as shown in FIG. 3 is covered.
Step 8: Cutting and removing the top end portion of the filling bag Then, as shown in FIG. 14, the protruding portion 32b of the water-stop grout filling bag 32 is removed by cutting.
Step 9: Placing the upper concrete As shown in FIG. 15, the upper concrete 12 (so-called superstructure) is cast to make the reinforced breakwater 4 higher than the existing breakwater 1 by a certain height.

  The present invention is not limited to the embodiment described above, and can be implemented with the following modifications.

  (i) In the above embodiment, the case where the existing caisson is damaged and applied to the original restoration work is applied, but the present invention is not limited to this and is not damaged. Of course, the same can be applied to the case where it is desired to increase the height of the existing breakwater (existing caisson).

  (ii) When a wave-dissipating function is required, a wave-dissipating block can be installed on the front surface, and as shown in FIG. 16, a recess 3a (or an opening) is formed on the front surface of the portal caisson 3 '. It is also possible to provide a structure incorporating a wave-absorbing structure.

  (iii) For example, if a crane with a lifting capacity of 4000 t is used, it can be hung up to a 3200 t portal caisson. Thus, construction can be performed.

  First, the front and rear wall portions of the portal caisson are manufactured in an onshore yard, and the front and rear wall portions are moved to a seaside yard by a crane ship and then poured into the caisson. And the rest of the portal caisson (upper wall, etc.) is manufactured. Or you may manufacture on a floating dock. In addition, the water depth of the offshore work yard is determined in consideration of the capacity of the crane ship when lifting the completed portal caisson.

  Then, the water in the portal caisson is discharged, and the portal caisson is suspended and transported to the installation site by a crane ship while being submerged in the sea, or the floating dock is rounded to the installation site.

  At the installation site, the portal caisson 3 ″ is half-sunk and suspended by the crane 23a of the crane ship 23, and is inserted from the side of the existing breakwater 1 as shown in FIGS. 17 (a) and 17 (b). It is moved to the position and installed in a state where it is placed on the upper side of the existing caisson. At this time, a plurality of rollers 3b are rotatably provided on the front and rear side wall portions of the portal caisson 3 '', and the plurality of rollers 3b are moved. In this case, the wall of the existing breakwater 1 is rolled, so there is no possibility that the portal caisson 3 "touches the existing breakwater 1 and damages the existing breakwater. Thus, regardless of the size of the portal caisson, the present invention Can be applied.

DESCRIPTION OF SYMBOLS 1 Existing breakwater 2 Existing caisson 3, 3 'Portal-type caisson 3A Upper side wall part 3Aa Input port 3B Front side wall part 3Bb Hollow part 3C Rear side wall part 3Cb Hollow part 4 Reinforced breakwater 6 Filled concrete 7 Filled sand 11 Cover concrete 12 Upper concrete 21 Water-stopping material 22 Outer wall 24 Bottom water-stopping concrete 25 Embedded piping 26, 29 Casting piping 27 Restraint lid 31 Grout material 32 Cylindrical filling bag

Claims (8)

A method of reinforcing a breakwater that increases the height of a caisson-type existing breakwater,
Producing a portal caisson having a size corresponding to an existing caisson constituting the existing breakwater;
Installing the portal caisson so as to cover the existing breakwater;
Filling the gap between the portal caisson and the existing breakwater with the portal caisson installed on the existing breakwater, and integrating the portal caisson with the existing breakwater; and With
The portal caisson has an upper side wall portion and two front and rear side wall portions extending in parallel.
The upper side wall has a plurality of inlets, the front and rear side walls have a hollow structure, and can be filled with the filler between the existing breakwater and the portal caisson. A method of reinforcing a breakwater, characterized in that is provided. Each inlet, the reinforcing method according to claim 1, wherein breakwater steel is hung inside for reinforcement. Filling the plurality of inlets of the integrated portal caisson with the filler, then providing a lid concrete covering the upper side wall, and providing an upper concrete on the lid concrete; The method for reinforcing a breakwater according to claim 1 or 2 . The gantry caisson, the said front and rear side wall portion, the breakwater according to claim 1, pipe for filling the water stopping material between the existing breakwater and the lower portion of the gate-shaped caisson is provided in advance Reinforcement method. Further, when integrating, between the front and rear side walls of the existing breakwater and the portal caisson, there is a step of providing a lid member that closes a gap formed between them,
The breakwater reinforcing method according to claim 1 , wherein the lid member is provided with an insertion hole for inserting a pipe for filling the gap with a filler. The portal caisson is provided with a cylindrical filling bag filled with a water stop material corresponding to the joint portion of the existing breakwater, and the existing breakwater and the gate caisson are filled with the water stop material into the filling bag. The method of reinforcing a breakwater according to any one of claims 1 to 5 , further comprising a step of forming a water stop portion for preventing seawater from entering between. The method of reinforcing a breakwater according to any one of claims 1 to 6 , further comprising a step of providing an outer wall extending toward an inner surface of the installed portal caisson on both sides in the width direction at an upper portion of the existing breakwater. The portal caisson is inserted from the side of the existing breakwater and is moved and installed in a direction in which the breakwater extends. A roller that rolls on the wall of the existing breakwater and regulates the contact between the existing breakwater and the portal caisson. The method for reinforcing a breakwater according to any one of claims 1 to 7 .