JP6630610B2 - How to improve wavebreak structures - Google Patents

Description

  The present invention relates to a method for improving a breakwater structure.

  Conventionally, breakwaters such as seawalls have been installed along the sea. Due to changes in the shape of the seabed ground and changes in the structures in the harbor, the height of the waves hitting the shore may be higher than previously assumed.In this case, wave conditions and existing Depending on the design tide level of the breakwater structure, there is a possibility that the waves may pass over the existing breakwater structure to the land side. For this reason, conventionally, there has been proposed an improved method of preventing a wave from breaking over a breakwater structure or reducing the flow rate (overtopping flow rate) of the wave breaking over the breakwater structure. ing. Patent Document 1 listed below discloses an example of such an improvement method.

  In the improvement method disclosed in Patent Literature 1 below, overtopping is prevented by attaching a wave-breaking wall having an L-shaped upside down shape to the upper end of a quay as an existing wavebreaking structure. . Specifically, the wave-absorbing wall is attached to the upper part of the quay such that a substantially horizontally extending upper portion of the wave-absorbing wall having the above-described shape projects from the upper end of the quay to the sea side. As a result, the waves rising on the sea side surface of the quay hit the portion of the wave-breaking wall extending in the substantially horizontal direction and are inverted, so that overtopping is prevented.

Japanese Utility Model Publication No. 55-140517

  However, in the improvement method of Patent Document 1, there is a possibility that a problem on the strength of the quay wall and / or the wave-break wall may occur.

  Specifically, a portion of the wave-absorbing wall projecting substantially horizontally from the upper end of the quay wall to the sea side is hit by waves from below, whereby the vicinity of the base of the projecting portion of the wave-breaking wall toward the sea, that is, the wave A large load is applied near the inverted L-shaped bent portion of the corrugated wall. For this reason, there is a possibility that the wave-absorbing wall may be damaged. In addition, the wave-absorbing wall is connected to the quay wall using bolts and nuts, but a large load is applied to the joint between the bolt and the nut when the wave hits the wave-absorbing wall, and the joint is damaged. There is a fear. A large load is also applied to the part of the quay wall where the wave-breaking wall is joined when the wave hits the wave-breaking wall. If the strength of the quay is insufficient due to aging, etc. May be damaged.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved method for improving a breakwater structure so as to suppress overtopping and to withstand the load applied by receiving waves.

  In order to achieve the above-mentioned object, for example, a method of forming a new revetment integrally with the existing revetment on the existing revetment by casting concrete on the existing revetment so as to raise the existing revetment. Can be considered. According to this method, since the existing revetment is raised, overtopping can be suppressed. In addition, the new revetment is formed so as to raise the existing revetment, and does not have a portion substantially protruding substantially horizontally from the upper end of the existing revetment toward the sea from the upper end of the existing revetment, such as a breakwater wall used in the conventional improvement method. This will prevent a large load from being applied to the newly built revetment. In addition, in this method, since a new seawall is integrated with the existing seawall by casting concrete, a large local load applied near the joint by the bolt and the nut in the conventional improved method is also required. The new revetment will not be applied and will not be added to the existing revetment. However, in this method, the weight of the new revetment formed on the existing revetment will be applied to the existing revetment, and it is difficult for the existing revetment to support the weight of the new revetment if the existing revetment is aging and brittle. However, the existing revetment may be damaged. Further, when the existing revetment is deteriorated, the existing revetment may be damaged by wave force.

  In addition, after the new seawall is formed integrally with the existing seawall, wave-breaking blocks are stacked on the seaside of the new seawall and the existing seawall, so that the height and wave power of the breaking waves are reduced by the wave-breaking block, It is also conceivable to reduce the load on the revetment and to reduce the load on the revetment. However, in this case, the beaches and reefs are lost by the wave-dissipating block, which causes a problem in the landscape and the environment.

  Then, in order to solve these problems, the inventor of the present application has invented a method for improving a wave-proof structure as described below.

  The method for improving a breakwater structure according to the present invention is a method for improving an existing breakwater structure installed along a seashore, wherein a wavebreaker that catches a wave is provided on the seashore of the existing breakwater structure. A construction step of constructing in a form capable of transmitting a load from the wave to the existing wavebreak structure on the side, a preparation step of preparing a wavebreak block to be mounted on the wavebreaker, and the prepared wavebreak block Mounting on the wavebreaker constructed in the construction step and fixing to the wavebreaker, and in the preparing step, as the wavebreak block, smoothly toward the sea side as going upward. A wavebreak block that has a wavebreak surface that protrudes in a curved shape, and the amount of wavebreak surface protruding toward the sea is greater than the amount of seawater above the existing wavebreak structure protruding toward the seaside. Prepare.

  According to this method of improving a breakwater structure, a wavebreak surface that projects in a smooth curved surface toward the offshore side toward the upper side is provided on the wavebreaker constructed on the sea side of the existing breakwater structure. A wavebreak block with a shape where the overhang of the existing wavebreak structure is larger than the amount of overhang to the offshore side of the existing breakwater structure is installed. Waves can be smoothly returned to the offshore side along the wavebreak surface by the wavebreak surface of the block, and overtopping can be prevented by a large amount of the wavebreak surface protruding offshore. For this reason, overtopping can be effectively suppressed. Further, since the wavebreak surface of the wavebreak block installed on the wavebreaker smoothly returns the waves to the offshore side along the wavebreak surface, the wave force applied to the wavebreak block can be passed. Therefore, the load applied to the wavebreak block itself can be reduced, and the load applied to the wavebreaker from the wavebreak block can also be reduced. As a result, it is possible to prevent the newly installed wavebreak block and wavebreaker from being damaged by the waves.

  In addition, in this improved method, a new wavebreaker is installed on the sea side of the existing wavebreaking structure so that the load from the wave can be transmitted to the existing wavebreaking structure. The corrugated body and the existing wavebreak structure can be opposed as one. For this reason, it is possible to give the improved wavebreaking structure including the newly installed wavebreaker and the existing wavebreaking structure high durability against wave force.

  In addition, in this improvement method, a new wavebreaker that catches waves is installed on the sea side of the existing wavebreak structure, so the old and fragile existing wavebreak structure is directly damaged by waves and damaged Can be prevented. Further, since the wavebreak block is installed on the newly installed wavebreaker, when the wavebreak block receives waves, no load is applied from the wavebreak block to the existing wavebreak structure. In addition, the weight of the wavebreak block can be supported by the newly installed wavebreaker, and the weight of the wavebreak block does not cover the existing wavebreak structure. Therefore, even if the existing wave-breaking structure is deteriorated and fragile, the existing wave-breaking structure is prevented from being damaged by the load applied from the wave-breaking block and / or the weight of the wave-breaking block. be able to.

  In addition, according to this improved method, overtopping can be suppressed by the function of the wavebreaker block as described above, and the existing wavebreaker can be used by the wavebreaker without the need to stack the wavebreaker block on the sea side of the new wavebreaker and wavebreaker block. The load applied to the breakwater can be reduced. For this reason, the disappearance of the sandy beach and the reef due to the installation of the wave-dissipating block can be prevented, and the adverse effects on the landscape and the environment can be suppressed.

In the method for improving a wave-preventing structure, in the construction step, concrete is applied to a wall, which is a portion forming a surface of the wave-preventing body that receives a wave, at a site where the existing wave-preventing structure is installed. formed by the set.

  In this case, in the construction step, the wall may be formed by casting concrete so as to cover the sea-side surface of the existing breakwater structure.

  According to this configuration, the seaside surface of the existing wave-breaking structure can be covered with the new wall structure, so that the deteriorated existing wave-breaking structure can be reinforced with the wall body.

In the method for improving a breakwater structure according to the first aspect of the present invention, in the construction step, the wall body is formed at an interval on the sea side of the existing breakwater structure, and the formed wall is formed. By filling the space between the body and the existing wave-breaking structure with a filler so that a load can be transmitted from the wall to the existing wave-breaking structure, made to form the breakwater member.

  In this configuration, since the wall is formed at an interval from the existing wave-breaking structure to the sea, the sea-side surface of the existing wave-breaking structure is so old that it is difficult to integrate the wall. Even if it becomes brittle, the wall body can be constructed, and further, a wavebreak block can be installed on the wall body. Moreover, in this configuration, the space between the new wall and the existing wave-breaking structure is filled with a filler so that the load can be transmitted from the wall to the existing wave-breaking structure. When a wave is received, the new wall, the filler, and the existing wave-proofing structure can be integrated to counter the wave force. For this reason, the improved wavebreak structure can have higher durability against wave force.

  In the method for improving a wave-proof structure, in the construction step, a height of a portion of the wave-proof body on which the wave-break block is placed in the installation step is lower than the height of the existing wave-break structure. It is preferable to form it.

  According to this configuration, for example, compared to a case where a new seawall is constructed on the existing wavebreak structure so as to raise the existing wavebreak structure, the work can be simplified and the cost for the work can be reduced. it can. Specifically, when constructing a new revetment to raise the existing breakwater structure, it is necessary to install a large formwork and large-scale shoring on the sea side to support the formwork. There is. Therefore, a large-scale construction is required. On the other hand, in the present configuration, the height of the portion where the breakwater block is placed in the wavebreaker is formed to be lower than the height of the existing wavebreak structure. Can be relatively small in size and the supporting structure to support it. Therefore, according to this configuration, it is possible to simplify the construction for the construction of the wavebreaker and to reduce the cost for the construction. In addition, by setting the part of the breakwater on which the breakwater block is placed at a lower height than the existing breakwater structure, the breakwater block can be supported by the existing breakwater structure from the land side. it can. For this reason, the wavebreak block can be provided with stronger durability against wave force. Furthermore, according to the present configuration, compared to the improved wavebreak structure by raising the existing wavebreak structure or installing a wavebreak block on the existing wavebreak structure, The height position of the upper end of the breakwater structure, that is, the height position of the upper end of the breakwater block can be reduced. As a result, it is possible to prevent the view over the improved breakwater structure from being deteriorated.

  In the method for improving a wave-proof structure, in the preparing step, as the wave-proof block, a steel frame having a curved plate portion having a curved shape along the wave-proof surface, and the wave-proof surface covering the curved plate portion. It is preferable to prepare a breakwater block having a concrete breakwater wall forming the following.

  According to this configuration, since the portion of the wavebreak block around the wavebreak surface that comes into contact with seawater is a concrete wavebreak wall, corrosion can be prevented. In addition, since the wavebreak block is a composite of the concrete wavebreak wall and the steel frame, the tenacity of the wavebreak block against external force can be increased. For this reason, even when the breakwater block receives a large external force such as the wave force of a tsunami, it is possible to prevent brittle fracture of the breakwater block. That is, in this configuration, it is possible to prevent brittle fracture of the wavebreak block while preventing corrosion of the wavebreak block.

  In the method for improving a wavebreak structure, the preparing step includes a manufacturing step of manufacturing the wavebreak block in a factory, and transporting the manufactured wavebreak block to a site where the existing wavebreak structure is installed. And a transporting step.

  According to this configuration, it is possible to reduce the work load required for manufacturing the wavebreak block. Specifically, if a wavebreaking structure having the same wave return function and wave overtopping function as the wavebreak block is formed by casting concrete on site, a formwork and It is necessary to construct a shoring to support the work on site, which increases the work load. On the other hand, according to this configuration, since the wavebreak block can be manufactured in a factory equipped with facilities, the work load can be reduced as compared with the case where the wavebreak block is formed at the above-mentioned site.

Further, an improved method of breakwater structure according to the second aspect of the present invention, after the installation process, the breakwater blocks were covered from the sea side opposite connecting said breakwater member and its breakwater blocks Ru further comprising a rear structure forming step of forming a rear structure.

  According to this configuration, a stronger structure can be formed by the wavebreak block and the back structure. Further, by connecting the wavebreak block and the wavebreaker with the back structure, the connection strength between the wavebreak block and the wavebreaker can be increased. Therefore, according to this configuration, the improved breakwater structure can be further strengthened.

  In this case, in the rear structure forming step, a frame plate is installed on the side opposite to the sea side with respect to the wavebreak block, and concrete is poured into a space between the frame plate and the wavebreak block. It is preferred that the back structure is formed by this.

  According to this configuration, the wavebreak block can be used as a part of a formwork for forming the back structure with concrete. Therefore, the cost for forming the back structure can be reduced.

  As described above, according to the method for improving a wavebreak structure according to the present invention, overtopping can be effectively suppressed, breakage of the wavebreak structure due to a load applied by receiving a wave can be suppressed, and the existing wavebreak structure can be suppressed. Even when the object is aging and brittle, the existing breakwater structure can be prevented from collapsing, and adverse effects on the landscape and the environment can be suppressed.

It is a perspective view showing the whole wave-proofing structure after having improved by the improvement method concerning a 1st embodiment of the present invention. FIG. 2 is a longitudinal sectional view of a wavebreak structure after the improvement of the first embodiment and its surroundings in a direction orthogonal to the coast. It is a perspective view of the wavebreak block which comprises the wavebreak structure. FIG. 4 is an explanatory diagram illustrating an improvement method according to the first embodiment. FIG. 4 is an explanatory diagram illustrating an improvement method according to the first embodiment. FIG. 4 is an explanatory diagram illustrating an improvement method according to the first embodiment. FIG. 4 is an explanatory diagram illustrating an improvement method according to the first embodiment. FIG. 4 is an explanatory diagram illustrating an improvement method according to the first embodiment. It is a longitudinal section of the breakwater structure after it was improved by the improvement method according to the second embodiment of the present invention, and the periphery thereof. It is explanatory drawing which shows the improvement method concerning 2nd Embodiment. It is explanatory drawing which shows the improvement method concerning 2nd Embodiment. It is explanatory drawing which shows the improvement method concerning 2nd Embodiment. It is explanatory drawing which shows the improvement method concerning 2nd Embodiment.

  Preferred embodiments of the present invention will be described with reference to the drawings.

(1st Embodiment)
FIG. 1 is a perspective view showing the entirety of the wavebreaking structure 1 after being improved by the improvement method according to the first embodiment of the present invention. The improvement method according to the first embodiment is to improve an existing seawall 100, which is an existing seawall structure originally installed along the coast, and to use the existing seawall 100 to improve the seawater. The structure 1 is formed.

  As shown in FIG. 4, the existing seawall 100 has a base part 101, an intermediate part 102, and an upper part 103.

  The base 101 is the lower end of the existing revetment 100. The ground on the sea side is lower than the ground on the land 111 side by a certain level, and the base portion 101 is installed on the lowered ground on the sea side. The intermediate portion 102 is a portion that extends upward from the base portion 101, and has a sea-side side surface that is inclined toward the land 111 as it goes upward. The upper portion 103 is a portion extending further upward from the intermediate portion 102, and has a vertical sea side surface. The height position of the upper end of the upper portion 103, that is, the height position of the top surface 104 of the existing revetment 100, substantially matches the height position of the ground on the land 111. The base portion 101, the intermediate portion 102, and the upper portion 103 are integrally formed of concrete. However, the structure of the existing revetment 100 is not necessarily limited to the above structure. That is, the base portion 101, the intermediate portion 102, and the upper portion 103 may have a shape other than the shape shown in FIG.

  In the improvement method according to the first embodiment, the entire existing revetment 100 is used, and a new part 2 (see FIG. 1) is provided on the sea side of the existing revetment 100 so as to be integrated with the existing revetment 100. The improved breakwater structure 1 including the existing seawall 100 and the newly constructed part 2 is formed.

  FIG. 2 shows a breakwater structure 1 in a direction orthogonal to the coast and a vertical cross section around the wavebreak structure 1. The newly installed part 2 is a part newly installed by the improvement method of the first embodiment, and includes a wall body 8, a plurality of wavebreak blocks 10, and a back structure 12.

  The wall body 8 is a wavebreaker that catches a wave, and is constructed on the sea side of the existing revetment 100 so as to transmit a load from the wave to the existing revetment 100. The wall body 8 is formed of concrete so as to cover the sea side surfaces of the base portion 101 and the intermediate portion 102 of the existing seawall 100. The wall body 8 has a predetermined thickness from the sea side surface of the existing seawall 100 to the sea side. The wall body 8 is installed on the ground adjacent to the sea side of the ground on which the base portion 101 of the existing seawall 100 is installed. The wall 8 has a sea surface 13 facing the sea and receiving waves.

  The height of the wall 8 is set lower than the height of the existing revetment 100. In other words, the height position of the upper end of the wall body 8 from the ground is set to a position lower than the height position of the upper end of the existing seawall 100 from the ground. That is, the top surface 14 of the wall body 8 is set at a position one step lower than the top surface 104 of the existing seawall 100, specifically, at a height position corresponding to the height position of the upper end of the intermediate portion 102 of the existing seawall 100. You.

  Since the wall 8 is formed by casting concrete on the seaside side of the existing seawall 100 as described later, the existing wall is formed at the contact interface between the wall 8 and the seaside side of the existing seawall 100. Integrated with revetment 100. Also, a plurality of anchors 105 are driven into the existing revetment 100 so as to protrude from the seaside side surface of the existing revetment 100, and the protruding portions of these anchors 105 are embedded in the wall 8 in the step of forming the wall 8. It is. Thereby, the integrity of the wall body 8 with respect to the existing seawall 100 is enhanced.

  The plurality of breakwater blocks 10 are installed on the top surface 14 of the wall 8 so as to be adjacent to each other along the coast. Each breaking block 10 has a breaking surface 16 facing the sea side (offshore side). The wave preventing surface 16 is a surface that receives a high wave when it hits the shore. The wavebreak surface 16 has a curved surface shape that smoothly approaches the offshore side as it goes upward, for example, a curved surface that has an arc shape or a parabolic shape in a vertical section. The amount of the sea surface 16 protruding offshore is greater than the amount of the upper portion 103 of the existing revetment 100 protruding offshore. In the state where each wavebreak block 10 is installed on the wall 8, the wavebreak surface 16 of each wavebreak block 10 and the sea surface 13 of the wall 8 are continuous, and after the wavebreak surface 16 and the sea surface 13 have been improved. The wave-proof surface 18 of the wave-proof structure 1 is formed.

  Each break block 10 has a frame 22 and a break wall 24 as shown in FIG.

  The frame 22 is made of steel and serves as a base of the breakwater block 10. The frame 22 has a curved plate portion 28, a bottom plate portion 29, and a pair of side plate portions 30.

  The curved plate portion 28 is made of a steel plate and has a curved shape along the wave preventing surface 16. The curved plate portion 28 has a land side surface 28a that is a curved surface that faces the land 111 side (the side opposite to the sea side) in a state where the wave preventing block 10 is arranged so that the wave preventing surface 16 faces the sea side.

  The bottom plate portion 29 is located at the lower end of the frame 22 and is made of a steel plate that is disposed horizontally. The bottom plate portion 29 has an edge located on the sea side in a state where the wave preventing block 10 is arranged so that the wave preventing surface 16 faces the sea side. The edge of the bottom plate portion 29 is arranged along the lower edge of the curved plate portion 28 and is welded to the land side surface 28a of the curved plate portion 28. The bottom plate 29 has a plurality of insertion holes 29a for inserting the anchors 32 (see FIG. 2). The anchor 32 is embedded in the wall 8 when the wavebreak block 10 is installed on the wall 8, and fixes the position of the wavebreak block 10.

  The pair of side plate portions 30 are arranged at an interval from each other in a direction along the sea-side edge of the bottom plate portion 29. The one side plate portion 30 is arranged near one end of the bottom plate portion 29 in a direction along the edge of the bottom plate portion 29 on the sea side. The other side plate 30 is disposed near an end of the bottom plate 29 opposite to the one end. Each side plate portion 30 is made of a steel plate, and the lower edge thereof is erected on the bottom plate portion 29 by being welded to the upper surface of the bottom plate portion 29. Each side plate portion 30 has an edge on the curved plate portion 28 side, and the edge has a curved shape along the land side surface 28 a of the curved plate portion 28. The edge of each side plate portion 30 on the curved plate portion 28 side is welded to the land side surface 28a of the curved plate portion 28.

  The above-described configuration of the frame 22 including the shape of the frame 22 and the form of fixing the bottom plate portion 29 by the anchor 32 is merely an example. The configuration of the frame according to the present invention is not necessarily limited to the configuration described above, and the frame may have a configuration different from the configuration described above.

  The breakwater wall 24 is a part that forms the wavebreak surface 16 of the wavebreak block 10. The breakwater wall 24 is made of concrete and covers the sea-side surface of the curved plate portion 28 and the peripheral edge of the curved plate portion 28. The lower end of the breakwater wall 24 projects slightly below the bottom plate 29.

  The back structure 12 is disposed behind the break wall 24 of the break block 10, specifically, on the land 111 side with respect to the break wall 24. The rear structure 12 interconnects the wall 8, the breakwater block 10, and the existing revetment 100. The rear structure 12 covers each side plate portion 30 of the frame 22 of each wavebreak block 10, the land side surface 28 a of the curved plate portion 28, the bottom plate portion 29, and the top surface 14 of the wall body 8. The space between the ten breakwater walls 24 and the curved plate portion 28 and the upper portion 103 of the existing seawall 100 is filled.

  The rear structure 12 has a top surface 12a that is substantially flush with the top surface 24a of the wave preventing wall 24 of the wave preventing block 10. The top surface 24a of the new portion 2 is formed by the top surface 24a of the breakwater wall 24 and the top surface 12a of the rear structure 12. The top surface 2a of the new part 2 is arranged at a position higher than the top surface 104 of the existing seawall 100, that is, at a position higher than the ground on the land 111.

  The configuration of the top surface 12a of the rear structure 12 and the side surface on the land 111 side are not necessarily limited to those shown in FIG. For example, the upper part of the new part 2 can be used for a promenade and other uses, and the shape of the top surface 12a of the back structure 12 and / or the side surface on the land 111 side is changed according to the use. Is also good.

  4 to 8 are explanatory diagrams illustrating a method of improving the wave-breaking structure according to the first embodiment. The improvement method according to the first embodiment includes a preparation step, a construction step, an installation step, and a back structure forming step. Hereinafter, with reference to FIGS. 2 to 8, each step of the method for improving the wave preventing structure according to the first embodiment will be described in detail.

(A) Preparation Step This preparation step is a step of preparing a plurality of breakwater blocks 10 at the site where the existing seawall 100 is installed. In the preparation step, when the wavebreak block 10 is installed on the wall body 8, the wavebreak block 16 has a smooth curved surface approaching offshore in a smoothly curved shape as it goes upward, and The wavebreak block 10 having a shape in which the amount of protrusion is larger than the amount of protrusion of the upper portion 103 of the existing revetment 100 to the offshore side is prepared. In addition, a block made of a composite of a steel frame 22 and a concrete break wall 24 is prepared as the break block 10. The preparation step specifically includes the following manufacturing step and transporting step.

(A-1) Manufacturing Process In this manufacturing process, the plurality of breakwater blocks 10 are manufactured at a factory remote from the site where the existing seawall 100 is installed. In this manufacturing process, first, a steel frame 22 (see FIG. 3) is manufactured. At this time, the curved plate portion 28, the bottom plate portion 29, and the pair of side plate portions 30 that are curved along the wave preventing surface 16 (see FIG. 2) are formed by processing a steel plate. After that, the frame 22 is manufactured by welding the curved plate portion 28, the bottom plate portion 29, and the pair of side plate portions 30 to each other. Next, a mold is assembled around the curved plate portion 28 of the produced frame 22, and ready-mixed concrete is poured into a space surrounded by the mold, and the ready-mixed concrete is solidified. As a result, a concrete wavebreak wall 24 that forms the wavebreak surface 16 by covering the surface of the curved plate portion 28 facing the sea and the peripheral edge of the curved plate portion 28 is formed. Thus, the wavebreak block 10 composed of the composite of the steel frame 22 and the concrete wavebreak wall 24 is formed.

  When manufacturing the wavebreak block 10, as the shape of the wavebreak surface 16, an optimum curved surface shape, amount of protrusion, etc. for suppressing overtopping based on the wave height and other conditions on the shore where the existing seawall 100 is installed. Is derived. For example, the optimum shape of the wave-proof surface 16 is derived using the area of the curve of the wave-proof surface 16 in the longitudinal section of the wave-proof surface 16. Then, the wavebreak surface 16 of the wavebreak block 10 is formed to have the derived shape. In addition, taking into account the lifting capacity of the crane used in the installation process described later and the concrete casting height in the factory in the manufacturing process, the protection of the wavebreak block 10 in the direction along the shore so that the weight and dimensions are not excessive. The width of the wave block 10 is set to about 2 m.

(A-2) Transporting Step In this transporting step, the plurality of breakwater blocks 10 manufactured in the factory in the manufacturing step are transported by land to a site where the existing seawall 100 is installed by a transport vehicle such as a trailer.

(B) Construction Step In this construction step, a wall body 8 as a wavebreaker for receiving waves is constructed on the sea side of the existing seawall 100 in a form capable of transmitting a load from the wave to the existing seawall 100. The construction of the wall 8 is performed by casting concrete on the sea side of the existing revetment 100 at the site where the existing revetment 100 is installed, thereby forming the concrete wall 8. At this time, the wall body 8 is formed such that the wall body 8 covers the sea side surfaces of the base part 101 and the intermediate part 102 of the existing seawall 100 and is integrated with the base part 101 and the intermediate part 102.

  In this construction process, first, as shown in FIG. 5, a number of anchors 105 are driven into the base portion 101 and the intermediate portion 102 of the existing seawall 100. These anchors 105 are driven into the base portion 101 and the intermediate portion 102 so as to protrude from their sea side surfaces. Next, the formwork 40 (see FIG. 6) is installed at a position away from the existing revetment 100 toward the sea. As the formwork 40, one that is lower than the height of the existing seawall 100 is installed. The formwork 40 is supported by a support (not shown) and a separator 41 interposed between the formwork 40 and the seaside side surface of the existing seawall 100. Further, the separator 41 secures an interval corresponding to the thickness of the wall body 8 to be formed between the formwork 40 and the seaside side surface of the existing seawall 100. A large number of reinforcing bars (not shown) are arranged in the space between the formwork 40 and the existing seawall 100.

  In addition, a plurality of anchors 32 are installed at positions where they are to be installed. At this time, for example, an unillustrated support member made of an angle member or other member is connected to the formwork 40 so as to extend from the formwork 40 to the space between the formwork 40 and the existing seawall 100, and the support is provided. By securing the anchors 32 to the member, each anchor 32 is placed at each predetermined location where they are to be placed. Further, instead of such an installation method, each anchor 32 is attached to a reinforcing bar arranged in a space between the formwork 40 and the existing seawall 100 so that each anchor 32 is attached to each predetermined location where they are to be installed. It may be installed at a position.

  Then, the fresh concrete 34 is poured into the space between the formwork 40 and the sea-side side surface of the existing seawall 100 from the land 111 by the pump car 210 and solidified to form the wall body 8. As described above, the wall body 8 is formed so that the wall body 8 covers the base portion 101 and the intermediate portion 102 of the existing seawall 100 on the sea side and has a lower height than the existing seawall 100. Each anchor 32 projects upward from the top surface 14 of the wall body 8 thus formed, and a lower portion of each anchor 32 is embedded in the wall body 8. After the formation of the wall body 8, the mold 40 is removed.

(C) Installation Step In this installation step, the plurality of breakwater blocks 10 prepared at the site in the preparation step, that is, the plurality of wavebreak blocks 10 manufactured at the factory and then transferred to the site in the transfer step, are subjected to the installation step. It is installed on the top surface 14 of the wall 8 formed by the above. At this time, as shown in FIG. 7, the breakwater block 10 is lifted by the crane 200 from above the land 111. Since the width of the wavebreak block 10 is set to about 2 m, the wavebreak block 10 is relatively lightweight, and a large crane 200 for lifting the wavebreak block 10 may not be used.

  When the breaking block 10 lifted by the crane 200 is lowered and mounted on the top surface 14 of the wall 8, the anchor 32 protruding from the top surface 14 of the wall 8 is inserted into the insertion hole 29 a of the bottom plate portion 29. The breakwater block 10 is mounted on the top surface 14 as described above, and the mounting position of the breakwater block 10 is adjusted so that the wavebreak surface 16 is continuous with the sea surface 13 of the wall body 8. By inserting the anchor 32 into the insertion hole 29a as described above, the relative position of the wavebreak block 10 to the wall 8 is fixed. In a state where the wavebreak block 10 is installed on the top surface 14 of the wall body 8, the lower end of the wavebreak wall 24 contacts the top surface 14, and the bottom plate portion 29 is arranged slightly above the top surface 14 with an interval. Is done. In the installation step, the plurality of breakwater blocks 10 are arranged along the coast, and the breakwater blocks 10 are mounted on the wall 8 so as to be adjacent to each other. Further, a space is formed between the breakwater wall 24 and the curved plate portion 28 of the breakwater block 10 installed in the installation process and the existing seawall 100.

(D) Back Structure Forming Step In the back structure forming step, the plurality of breakwater blocks 10 arranged along the coast in the installation step are covered from the opposite side (land side) from the sea side, and the breakwaters are provided. A back structure 12 (see FIG. 2) for interconnecting the block 10, the wall 8 and the existing revetment 100 is formed.

  In the rear structure forming step, first, a frame plate 42 (see FIG. 8) is installed on the side opposite to the sea side with respect to the wavebreak block 10. Specifically, the frame plate 42 is installed on the top surface 104 of the existing seawall 100 along the edge of the top surface 104 on the sea side. As a result, the breakwater walls 24 and the curved plate portions 28 (see FIG. 3) of the plurality of breakwater blocks 10, the upper portion 103 of the existing seawall 100, the frame plate 42, and the top surface 14 of the wall body 8 are surrounded. Space is formed. As shown in FIG. 8, the fresh concrete 36 is poured into the space from the land 111 by a pump car 210 and solidified to form the rear structure 12 (see FIG. 2). After the formation of the back structure 12, the frame plate 42 is removed.

  Through the steps as described above, the breakwater structure according to the first embodiment is improved.

  In the method for improving a wave-breaking structure according to the first embodiment, the wall surface 8 constructed on the sea side of the existing revetment 100 has a wave-breaking surface 16 that protrudes in a smooth curved surface toward the offshore side as going upward. The wavebreak block 10 having a shape in which the amount of protrusion of the wavebreaking surface 16 is larger than the amount of protrusion of the upper portion 103 of the existing seawall 100 is installed. For this reason, the breaking wave can be received by the wall body 8 and the wavebreak block 10, and the wave can be smoothly returned to the offshore side along the wavebreak surface 16 by the wavebreak surface 16 of the wavebreak block 10. In addition, overtopping can be prevented by the large amount of the wavebreak surface 16 protruding offshore. Therefore, according to the improvement method of the first embodiment, overtopping of the improved breakwater structure can be effectively suppressed.

  Further, since the wavebreak surface 16 of the wavebreak block 10 smoothly returns the waves to the offshore side along the wavebreak surface 16, the wave force applied to the wavebreak block 10 can be passed. Therefore, the load applied to the breakwater block 10 itself can be reduced, and the load applied to the wall 8 from the breakwater block 10 can be reduced. As a result, it is possible to prevent the newly-installed wavebreak block 10 and the wall 8 from being damaged by receiving the waves.

  In the improvement method of the first embodiment, the new wall 8 is installed on the sea side of the existing revetment 100 in such a manner that the load from the waves can be transmitted to the existing revetment 100. 8 and the existing revetment 100 can be opposed as one. Therefore, the improved wavebreak structure 1 including the wall body 8 and the existing seawall 100 can have high durability against wave force.

  Further, in the improvement method of the first embodiment, the newly built wall 8 that catches the waves is installed on the sea side of the existing revetment 100, so that the existing revetment 100 that has become fragile due to aging is directly damaged by the waves. Can be prevented. In the improvement method of the first embodiment, since the breakwater block 10 is installed on the new wall body 8, when the wavebreak block 10 receives a wave, a load is applied from the breakwater block 10 to the existing seawall 100. Not added. In addition, the weight of the breakwater block 10 can be supported by the new wall body 8, and the weight of the breakwater block 10 does not cover the existing seawall 100. Therefore, even if the existing revetment 100 is deteriorated and fragile, the existing revetment 100 can be prevented from being damaged by the load applied from the breakwater block 10 and / or the weight of the breakwater block 10.

  In addition, in the improved method of the first embodiment, as described above, overtopping can be suppressed by the function of the breakwater block 10 without stacking the wavebreak block on the sea side of the newly installed wall body 8 and the breakwater block 10. At the same time, the load applied to the existing revetment 100 by the wall body 8 can be reduced. For this reason, the disappearance of the sandy beach and the reef due to the installation of the wave-dissipating block can be prevented, and the adverse effects on the landscape and the environment can be suppressed.

  Further, in the improvement method of the first embodiment, the wall 8 is formed by casting concrete on the seawall of the existing revetment 100 so as to cover the seaside. That is, the seawall surface of the existing revetment 100 can be covered with the new wall 8, so that the old revetment 100 can be reinforced with the wall 8.

  In the improvement method of the first embodiment, the wall 8 is formed at a height lower than the existing seawall 100. Therefore, for example, compared to a case where a new revetment is constructed on the existing revetment 100 so as to raise the existing revetment 100, the construction can be simplified and the cost for the construction can be reduced. Specifically, when constructing a new seawall so as to cover the seaside surface of the existing seawall 100 and raise the existing seawall 100, a large-sized formwork and a large-scale for supporting the formwork are required. Shoring needs to be installed on the sea side of the existing revetment 100. In this case, a large-scale construction is required. On the other hand, in the improvement method of the first embodiment, since the wall 8 is formed at a height lower than the existing revetment 100, the wall 8 can be formed by the mold 40 having a relatively small height. A relatively small shoring may be installed to support the formwork 40. Therefore, according to the improved method of the first embodiment, the work for forming the wall 8 can be simplified, and the cost for the work can be reduced.

  In addition, by forming the wall 8 at a height lower than the existing revetment 100, the breakwater block 10 and the rear structure 12 installed on the wall 8 can be supported by the existing revetment 100 from the land side. For this reason, the wavebreak block 10 can have strong durability against wave force.

  In addition, the height position of the upper end of the breakwater block 10 can be made relatively low while the breakwater block 10 is installed on the wall 8. For this reason, it is possible to prevent the view over the breakwater block 10, that is, the view over the improved breakwater structure 1 from being deteriorated.

  In the improvement method of the first embodiment, the wavebreak block includes the steel frame 22 having the curved plate portion 28 and the concrete wavebreak wall 24 that covers the curved plate portion 28 and forms the wavebreak surface 16. 10 is used. For this reason, since the portion of the wavebreak block 10 around the wavebreak surface 16 that comes into contact with seawater is the concrete wavebreak wall 24, corrosion can be prevented. Further, since the wavebreak block 10 is a composite of the concrete wavebreak wall 24 and the steel frame 22, the tenacity of the wavebreak block 10 against external force can be increased. For this reason, even when the wavebreak block 10 receives a large external force such as the wave force of a tsunami, it is possible to prevent brittle fracture of the wavebreak block 10. Therefore, according to the improved method of the first embodiment, it is possible to prevent the breakage block 10 from being corroded while preventing the breakage block 10 from being brittle.

  In the improvement method of the first embodiment, the breakwater block 10 is manufactured at a factory, and the manufactured breakwater block 10 is transported to prepare the breakwater block 10 at the site where the existing revetment 100 is installed. I do. If a wavebreaking structure having the same wave return function and wave overtopping function as the wavebreak block 10 is formed by casting concrete on site, a formwork and a supporting structure for supporting the formwork are required. It is necessary to carry out the work on site, which increases the work load. On the other hand, according to the improved method of the first embodiment, since the wavebreak block 10 can be manufactured in a factory equipped with facilities, the work load can be reduced as compared with the case where the wavebreak block 10 is formed on site.

  Further, in the improvement method of the first embodiment, the back structure that covers the breakwater block 10 from the side opposite to the sea (land 111 side) and connects the breakwater block 10, the wall body 8, and the existing seawall 100 with each other. The body 12 is formed. For this reason, the connection strength between the breakwater block 10, the wall 8, and the existing seawall 100 can be increased. Therefore, the improved wavebreaking structure 1 can be further strengthened.

  Further, in the improved method of the first embodiment, the frame plate 50 is installed on the opposite side of the sea side (land 111 side) with respect to the wavebreak block 10, and the gap between the frame plate 50 and the wavebreak block 10 is provided. The back structure 12 is formed by casting concrete in the space. That is, the wavebreak block 10 can be used as a part of a mold for forming the back structure 12 with concrete. Therefore, the cost for forming the back structure 12 can be reduced.

  In the improvement method of the first embodiment, the preparation step, the installation step, and the back structure forming step can be performed from the land 111, so that the work load can be reduced as compared with the case where the work is performed from the sea side.

(2nd Embodiment)
FIG. 9 shows a wave-breaking structure 1 after being improved by the improvement method according to the second embodiment of the present invention and a vertical cross section around the wave-proof structure 1. In the improvement method according to the second embodiment, a wavebreaker 55 composed of the wall 8 and the filler 54 is constructed on the sea side of the existing revetment 100 in a form capable of transmitting a load from waves to the existing revetment 100. Specifically, the wall body 8 is provided at a position spaced from the existing revetment 100 toward the sea. The space between the wall 8 and the existing revetment 100 and the space between the rear structure 12 on the wall 8 and the existing revetment 100 are filled with a filler 54 made of crushed stone. Is paved into sidewalk 56.

  FIG. 10 to FIG. 13 are explanatory diagrams showing a method of improving the wave-proofing structure according to the second embodiment. The improvement method according to the second embodiment includes a preparation step, a construction step, a first filling step, an installation step, a back structure forming step, a second filling step, and a pavement step. Hereinafter, with reference to FIGS. 9 to 13, each step of the method of improving the wave-proof structure according to the second embodiment will be described in detail.

(A) Preparation Step This preparation step is the same as the preparation step in the first embodiment, and is a step of preparing a plurality of breakwater blocks 10 at the site where the existing seawall 100 is installed.

(B) Construction Step In this construction step, a wavebreaker 55 for receiving a wave is constructed on the sea side of the existing revetment 100 in a form capable of transmitting a load from the wave to the existing revetment 100. This construction step includes the following wall forming step and first filling step.

(B-1) Wall Forming Step In this wall forming step, concrete 8 is cast at the site where the existing seawall 100 is installed, so that the wall 8 for constructing the wavebreaker 55 is moved to the existing seawall 100. Formed at a distance from the sea to the sea. Specifically, first, as shown in FIG. 10, the back mold 62 is installed at a position away from the existing revetment 100 toward the sea. As the back formwork 62, a formwork lower than the height of the existing seawall 100 is installed. A plurality of separators 65 are interposed between the rear formwork 62 and the seaside side surface of the existing seawall 100, thereby supporting the rear formwork 62 at a distance from the existing seawall 100.

  Next, a front formwork 64 is set at a position further away from the back formwork 62 toward the sea, and the front formwork 64 is supported by a support (not shown). As the front formwork 64, one that is lower than the height of the existing seawall 100 is installed. An interval corresponding to the thickness of the wall body 8 to be formed is secured between the back mold 62 and the front mold 64. In the second embodiment, the thickness increases from the upper part to the lower part of the wall body 8 so that the wall body 8 can stand independently on the ground and independently support the wavebreak block 10 and the rear structure 12 from below. Is formed in a shape that increases. For this reason, a space having a shape corresponding to the shape of the wall body 8 is formed between the back mold 62 and the front mold 64. A large number of reinforcing bars (not shown) are arranged in the space between the back mold 62 and the front mold 64. In addition, a plurality of anchors 32 are installed at positions where they are to be installed. At this time, the same installation method as the installation method of the anchor 32 in the construction process of the first embodiment is applied.

  Then, the fresh concrete 66 is poured into the space between the rear formwork 62 and the front formwork 64 from above the land 111 by the pump car 210 and solidified to form the wall 8. As described above, the wall body 8 having a lower height than the existing seawall 100 is formed. Each anchor 32 projects upward from the top surface 14 of the wall body 8 thus formed, and a lower portion of each anchor 32 is embedded in the wall body 8. After the formation of the wall body 8, the rear mold 62 and the front mold 64 are removed.

(B-2) First Filling Step In the first filling step, as shown in FIG. 11, the space behind the wall body 8 formed in the above-described construction step, that is, the space between the wall body 8 and the existing seawall 100. Is filled with a packing 54 made of crushed stone. At this time, the filling material 54 is filled up to almost the same height as the top surface 14 of the wall body 8. The first filling step is performed by injecting crushed stone into the space between the wall body 8 and the existing seawall 100 with the shovel 220 from the land 111. By filling the space between the wall 8 and the existing seawall 100 with the filler 54 as described above, the wave preventive body 55 composed of the wall 8 and the filler 54 is formed.

(C) Installation Step In this installation step, similarly to the installation step of the first embodiment, a plurality of wavebreak blocks 10 prepared on site in the preparation step are placed on the top surface 14 of the wall 8 formed in the installation step. install.

(D) Back Structure Forming Step In this back structure forming step, the surface of the wave preventing wall 24 on the land 111 side of the wave preventing block 10 and the frame 22 are covered, and the wave preventing block 10 and the wall body 8 are connected to each other. The connecting rear structure 12 (see FIG. 9) is formed. The rear structure 12 is formed by casting concrete on the land 111 side of the plurality of wavebreak blocks 10 installed on the top surface 14 of the wall 8 so as to line up along the coast in the installation process.

  Specifically, first, a frame plate 70 (see FIG. 13) is installed along the coast on the land 111 side (the side opposite to the sea side) with respect to the plurality of breakwater blocks 10. The frame plate 70 is placed on the filling 54 filled in the first filling step along the boundary between the filling region and the wall 8. Then, the space between the breakwater block 10 and the frame plate 70 by the pump truck 210 from the land 111, specifically, the land 111 side surface of the breakwater wall 24 and the land side surface 28a of the curved plate portion 28 (see FIG. 3). Fresh concrete 68 (see FIG. 13) is poured into the space between the frame structure and the frame plate 50, and is solidified to form the back structure 12 (see FIG. 9). The ready-mixed concrete 68 also enters the gap between the lower surface of the bottom plate portion 29 of the wavebreak block 10 and the top surface 14 of the wall body 8, and enters the gap and solidifies the concrete to prevent the wavebreak block 10 and the wall body from entering. 8 are interconnected. After the formation of the back structure 12, the frame plate 70 is removed.

(E) Second Filling Step In the second filling step, the space behind the back structure 12 formed in the back structure forming step, that is, the space between the back structure 12 and the existing seawall 100 is filled with the filler 54. (See FIG. 9). That is, in the second filling step, the crushed stone is further filled on the filler 54 filled in the first filling step. This second filling step is performed by throwing crushed stone into the space between the rear structure 12 and the existing revetment 100 from above the land 111 with a shovel as in the first filling step. In the second filling step, the filler 54 is filled up to a position slightly below the upper end of the existing seawall 100.

(F) Pavement Step In this pavement step, a pavement 56 (see FIG. 9) is formed by paving the filling 54 filled in the second filling step.

  Through the steps described above, the breakwater structure according to the second embodiment is improved.

  In the improvement method of the second embodiment, since the wall 8 is formed at an interval from the existing seawall 100 to the sea, the seaside side surface of the existing seawall 100 is so old that it is difficult to integrate the wall. The wall 8 can be provided even in the case of becoming brittle due to the breakage, and the wavebreak block 10 and the rear structure 12 can be installed on the wall 8.

  Moreover, in the improvement method of the second embodiment, the space between the wall 8 and the existing revetment 100 and the space between the rear structure 12 and the existing revetment 100 are replaced by the wall 8, the breakwater block 10 and the rear. It is filled with the filling 54 so that the load can be transmitted from the structure 12 to the existing revetment 100. Therefore, when the wall 8 and the breakwater block 10 receive a wave, the new part 2 composed of the wall 8, the breakwater block 10 and the back structure 12, the existing seawall 100, and the filler 54 are integrated. It becomes possible to counter wave power. Therefore, the improved wavebreak structure 1 can have higher durability against wave force.

  Other effects of the improvement method of the second embodiment are the same as the effects of the improvement method of the first embodiment.

  The method for improving a wave-proofing structure according to the present invention is not necessarily limited to the above-described method. As a method of improving the wave-proofing structure according to the present invention, for example, the following configuration can be adopted.

  The height of the wall formed in the construction process can be set arbitrarily. For example, the height of the wall may be equal to or higher than that of the existing revetment, or may be smaller than the height of the wall shown in the drawings according to the embodiment.

  The height dimension of the wavebreak block can be set arbitrarily. Then, by changing at least one of the height of the wall and the dimension of the wavebreak block in the height direction, it is possible to arbitrarily set the height position of the upper end of the improved wavebreak structure. In addition, the shape of the wavebreak surface of the wavebreak block can be arbitrarily set. The correlation between the height position of the upper end of the improved breakwater structure, the shape of the breakwater surface of the breakwater block, the overtopping flow rate, and the wave pressure acting on the breakwater block can be derived by hydraulic experiments, etc. Based on the derived correlation, it is possible to derive the height position of the upper end of the wavebreak structure and the shape of the wavebreak surface of the wavebreak block, which is sufficient for suppressing overtopping. The height position of the upper end of the wavebreaking structure and the shape of the wavebreaker surface of the wavebreaker block can be set based on the derived height position of the upper end of the wavebreaker structure and the shape of the wavebreaker surface of the wavebreaker block.

1 Wavebreaking structure 8 Wall (wavebreaker)
DESCRIPTION OF SYMBOLS 10 Wavebreak block 12 Rear structure 16 Wavebreak surface 22 Frame 24 Wavebreak wall 42, 70 Frame plate 54 Filling material 55 Wavebreaker 100 Existing seawall (existing wavebreak structure)
103 Upper part

Claims (6)

A method for improving an existing breakwater installed along a coast,
A construction step of constructing a wavebreaker that catches a wave on the sea side of the existing wavebreaking structure in a form capable of transmitting a load from the wave to the existing wavebreaking structure,
A preparing step of preparing a wavebreak block to be mounted on the wavebreaker,
An installation step of mounting the prepared wavebreak block on the wavebreak body constructed in the construction step and fixing the wavebreak block to the wavebreak body,
In the preparing step, as the wavebreak block, the wavebreak block has a wavebreak surface protruding toward the sea side as it goes upward in a smoothly curved shape, and the amount of the wavebreak surface protruding toward the seaside is the amount of the existing wavebreak structure. Prepare a breakwater block that is larger than the amount of the upper part protruding to the sea side ,
In the construction step, concrete is cast at a site where the existing wavebreaking structure is installed on a wall, which is a portion forming a surface of the wavebreaker that receives a wave, so that the existing wavebreaking structure is formed. The wall is formed at an interval on the sea side of an object, and a space between the formed wall and the existing wave-breaking structure transmits a load from the wall to the existing wave-breaking structure. An improved method of a wave-proofing structure, wherein the wave-breaking body composed of the wall and the filler is formed by filling with a filling material as possible. Wherein in the construction step, to form a lower height than breakwater structure the height of the existing portion for mounting the breakwater blocks the installation process of the breakwater member, according to claim 1 How to improve the breakwater structure. In the preparing step, as the wavebreak block, a steel frame having a curved plate portion having a curved shape along the wavebreak surface, and a concrete wavebreak wall that covers the curved plate portion and forms the wavebreak surface. The method for improving a wavebreak structure according to claim 1 or 2 , wherein a wavebreak block having the following formula is prepared. The preparation step includes: a manufacturing step of manufacturing the breakwater block in a factory; and a transfer step of transferring the manufactured breakwater block to a site where the existing breakwater structure is installed. The method for improving a waveproof structure according to any one of claims 1 to 3 . A method for improving an existing breakwater installed along a coast,
A construction step of constructing a wavebreaker for receiving a wave on the sea side of the existing wavebreaking structure in a form capable of transmitting a load from the wave to the existing wavebreaking structure,
A preparing step of preparing a wavebreak block to be mounted on the wavebreaker,
An installation step of mounting the prepared wavebreak block on the wavebreaker constructed in the construction step and fixing the wavebreak block to the wavebreaker,
In the preparing step, as the wavebreak block, the wavebreak block has a wavebreak surface protruding toward the sea side as it goes upward in a smoothly curved shape, and the amount of the wavebreak surface protruding toward the seaside is the amount of the existing wavebreak structure. Prepare a breakwater block that is larger than the amount of the upper part protruding to the sea side,
The method further comprises, after the installation step, a back structure forming step of covering the wavebreak block from the side opposite to the sea and forming a back structure connecting the wavebreak block and the wavebreaker . improved methods of anti-wave structure. In the back structure forming step, a frame plate is installed on a side opposite to the sea side with respect to the wavebreak block, and concrete is poured into a space between the frame plate and the wavebreak block, thereby forming the rear side. The method for improving a waveproof structure according to claim 5 , wherein the structure is formed.

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