JP2011214238A - Water breaking structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water breaking structure which reduces wave pressure applied to an offshore-side wall surface, even when an upper part of the offshore-side wall surface has a shape jutting to the offshore side for obtaining non-wave-overtopping performance.SOLUTION: The water breaking structure 10 erected toward the offshore side includes an upper part provided with the offshore-side wall surface 20 in the shape jutting to the offshore side so as to repel waves coming from the offshore side. The offshore-side wall surface 20 is provided with irregularities which are alternately repeated along a wave guiding direction α when repelling the waves, while the irregularities are provided to at least part of the portion jutting from the deepest portion to the offshore side in a view from the offshore side in the guiding direction α of the offshore-side wall surface 20.

Description

  The present invention relates to a breakwater protection structure such as a breakwater and a quay that protects a ship, land life, buildings and the like from wave overtopping waves and wave forces in harbors and coastal areas.

  For example, an upright revetment 110 using an upright caisson 112 as shown in FIG. 12 has been conventionally used as a breakwater protection structure.

  In this upright revetment 110, the wave coming from the offshore side is stopped by hitting the offshore side wall surface 114 rising in the vertical direction, thereby protecting the ship and human life from the wave force. However, in order to obtain sufficient non-overtopping performance, it is necessary to increase the top height or to pile up a wave-dissipating block on the front side (offshore side) of the offshore wall surface 114.

  In view of this, a revetment (a wave-breaking structure) having a shape in which the upper part of the offshore wall surface 114 protrudes to the offshore side so as to repel waves coming from the offshore side has been developed. Specifically, for example, like the revetment 120 described in Patent Document 1 (see FIG. 13), the upper inclined portion 124 that inclines to the offshore side so that the waves coming from the offshore side rebound to the upper portion of the offshore wall surface 122. It was possible to obtain high non-overtopping performance while keeping the top height low. By using this revetment 120, wave overtopping can be reduced without having to pile up wave-dissipating blocks on the front side of the offshore wall surface 122, so that natural environments such as sandy beaches and corals need not be filled with wave-dissipating blocks.

JP-A-11-241323

  The wave breaker structure 120 having the upper inclined portion 124 on the offshore wall surface 122 can obtain a high non-overtopping performance while suppressing the height of the top edge as compared with the upright revetment. There is a tendency that the wave pressure against 122 is larger than that of the upright revetment. This is for the purpose of forcibly changing the movement direction of the water mass coming from the offshore side and colliding with the offshore wall surface 122 by the upper inclined portion 124 to the offshore direction.

  When the wave pressure increases in this way, the vertical component of the wave pressure acting on each part of the offshore wall surface 122 acts so as to push the wave preventing structure upward, thereby damaging the wave preventing structure and the wave preventing structure. There were concerns about things becoming unstable.

  Therefore, in view of the above problems, the present invention provides a wave-breaking structure that can reduce the wave pressure on the offshore wall surface even when the upper part of the offshore wall surface has a shape protruding to the offshore side in order to obtain non-overtopping performance. It is an issue to provide.

  Therefore, in order to solve the above-described problems, the present invention is a wave-proof structure that is erected facing offshore, and has an offshore shape that projects to the offshore so that waves coming from offshore are rebounded at the top. The offshore wall surface has irregularities that are alternately repeated along the wave guiding direction when the wave rebounds, and the irregularities are located on the offshore side in the guiding direction of the offshore wall surface. It is provided in at least a part of the portion protruding to the offshore side from the deepest depth when viewed from the side.

  Since the offshore wall surface has a shape protruding to the offshore side in this way, waves coming from the offshore side to the offshore wall surface rebound to the offshore side, so that overtopping can be reduced. Moreover, when the waves are rebounded by the offshore wall surface, the waves guided along the wall surface are broken by colliding with the uneven projections repeated in the traveling direction, thereby reducing the wave pressure on the offshore wall surface. To do.

  In the wave-breaking structure according to the present invention, the irregularities are alternately repeated in the entire guiding portion of the offshore wall surface over the entire area protruding from the deepest depth when viewed from the offshore side. It is preferable.

  The range in which this wave is likely to travel along the offshore wall when the wave is rebounded by the offshore wall at various tidal and wave conditions (i.e., from the deepest depth when viewed from the offshore side in the guide direction) Since the unevenness is repeated in the whole area of the portion protruding to the offing side), the wave guided along the wall surface can be surely broken, thereby effectively reducing the wave pressure on the offing wall surface. .

  Furthermore, the region where the irregularities on the offshore wall surface are alternately repeated exists in a range of 50% or more in the horizontal direction of the offshore wall surface when the upper end side is viewed along the wall surface from the lower end of the offshore wall surface. Then, the wave pressure with respect to the entire offshore wall surface can be effectively reduced.

  The region where the unevenness on the offshore wall surface is alternately repeated may have a uniform cross-sectional shape in the horizontal direction or the substantially horizontal direction.

  According to such a configuration, it is possible to effectively reduce the wave pressure over the entire region having a uniform cross-sectional shape in which irregularities are alternately repeated in the horizontal direction of the offshore wall surface.

  In this case, in the region where the unevenness on the offshore wall surface is alternately repeated, an orthogonal surface orthogonal or substantially orthogonal to the traveling direction of the wave guided along the offshore wall surface is formed in a part of the unevenness. If so, the wave guided along the offshore wall surface collides with an orthogonal surface that is orthogonal or substantially orthogonal to the traveling direction, so that the wave is more effectively broken.

  Further, the unevenness of the offshore wall surface extends in a horizontal direction or a substantially horizontal direction, and has a plurality of ridges arranged in parallel or substantially in parallel with a gap in the guide direction, and a ridge adjacent to the guide direction. It may be defined by a bottom surface located between them.

  According to such a configuration, since the guided wave collides with the ridge extending in the direction orthogonal to or substantially orthogonal to the traveling direction, the wave is effectively broken in the entire region where the ridge extends in the horizontal direction of the offshore wall surface. Wave pressure can be reduced.

  In this case, the ridge has an orthogonal surface that is orthogonal or substantially orthogonal to the traveling direction of the wave guided along the offshore wall surface, so that the wave guided along the offshore wall surface travels. Since the bump strikes an orthogonal plane that is orthogonal or substantially orthogonal to the direction, the ridge can break the wave more effectively.

  It is preferable that the width dimension of the bottom surface in the guiding direction is larger than the height dimension of the protrusion in the direction perpendicular to the guiding direction and perpendicular to the horizontal direction.

  According to such a configuration, the wave guided to the offshore wall surface surely enters the bottom surface between the ridges arranged in parallel or substantially parallel to the guide direction, and this entering wave collides with the entire side surface of the ridge. It is effectively destroyed. That is, if the interval between the ridges is narrow, the guided wave cannot enter the bottom surface, so that it only collides with the protruding tip end portion of the ridge, and the wave is not greatly broken.

  As described above, according to the present invention, there is provided a wave-breaking structure capable of reducing the wave pressure on the offshore wall surface even if the upper part of the offshore wall surface protrudes to the offshore side in order to obtain non-overtopping performance. be able to.

It is a section perspective view in the state where the wave-proof structure concerning this embodiment was installed. It is a longitudinal cross-sectional view of the said wave-proof structure. FIG. 3 is a partially enlarged view of the offshore wall surface of FIG. 2. It is a partial expanded sectional view of the offshore wall surface in the wave-proof structure which concerns on other embodiment. It is a partial expanded sectional view of the offshore wall surface in the wave-proof structure which concerns on other embodiment. It is a figure for demonstrating the shape of the protrusion of the offshore wall surface which concerns on other embodiment. (A) is a partially enlarged perspective view of a wave-breaking structure in which protrusions are arranged vertically and horizontally on the offshore wall surface, and (B) is a wavebreaking structure in which protrusions are lined up in a staggered manner on the offshore wall surface. FIG. It is a longitudinal cross-sectional view of the state which installed the wave-proof structure which concerns on other embodiment. In Experiment 1, it is a graph which shows the experimental result when the horizontal axis | shaft is made into the protrusion height H converted into the field, and the vertical axis | shaft is made into the wave pressure reduction rate. In Experiment 1, it is a graph which shows an experimental result when a horizontal axis | shaft is made into the ratio of the protrusion width B with respect to the protrusion height H, B / H, and the vertical axis | shaft is made into the wave pressure reduction rate. In Experiment 2, it is a graph which shows an experimental result when a horizontal axis is ratio of bottom face width D to ridge width B, D / B, and a vertical axis is a wave pressure reduction rate. It is a longitudinal cross-sectional view of a state where a conventional upright revetment is installed. It is a cross-sectional perspective view of the state which installed the wave-proof structure in which the upper inclination part was provided in the upper part of the conventional offshore wall surface.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  The breakwater structure according to the present embodiment is used for a breakwater such as a breakwater or a quay. As shown in FIGS. 1 and 2, the wave-breaking structure of the present embodiment is installed on the foundation K composed of sand and a rubble mount so as to face offshore. The foundation K is not limited to such a configuration, and may be any known configuration. Such a foundation K is not essential for installing the wave-breaking structure 10.

  The wave breaker structure 10 includes an offshore wall surface 20 facing offshore, a top end surface 12, a land wall surface 14, and a bottom surface 15. The top end surface 12 is a surface extending in the horizontal direction at the upper end (top end) of the wave preventing structure, the land side wall surface 14 is a surface standing upright in the land side, and the bottom surface 15 is the wave preventing structure. This is the surface that contacts the foundation K when the object 10 is installed.

  The offshore wall surface 20 has a curved surface shape that is recessed from the offshore side toward the shore, and the upper inclined portion 22 that inclines so as to protrude toward the offshore side toward the upper side, and the outer slope toward the offshore side. And a lower inclined portion 24 inclined to the land side.

  The upper inclined portion 22 is a portion that prevents overtopping by receiving waves coming from the offshore side and bounces back to the offshore side. Specifically, the upper inclined portion 22 changes the traveling direction of the waves to the offshore direction by guiding a wave arriving from the offshore side to the upper end side along the upper inclined portion 22. Therefore, the upper inclined portion 22 is curved so as to easily guide the wave coming from the offshore side to the upper end side of the upper inclined portion 22 (or the offshore wall surface 20). The upper inclined portion 22 is an area that always includes the height position of the still water surface S, including at low tide and at high tide, when it is installed on the coast so as to receive incoming waves. Thus, it is formed from below the water surface height position at the time of drawing by the wave W (see FIG. 2) having the maximum design wave height to the top edge height position of the offshore wall surface 20.

  The design maximum wave height refers to the maximum wave height assumed in the sea area where the wave-breaking structure 10 is installed, and is set in order to design the wave-breaking structure 10. Further, in the wave-breaking structure 10 of the present embodiment, the vertical surface 16 exists above the upper inclined portion 22 of the offshore wall surface 20, and this vertical surface 16 is the upper inclined portion 22 of the offshore wall surface 20. It does not fulfill the function of receiving and rebounding the wave as a part, and the uppermost portion of the upper inclined portion 22 withstands the wave pressure acting when receiving and rebounding the wave as the upper inclined portion 22 and is necessary as a structure. A thickness necessary for obtaining a certain strength is formed. Therefore, in this embodiment, such a portion of the vertical surface 16 is not included in the offshore wall surface 20.

  The offshore wall surface 20 has irregularities that are alternately repeated along the wave guide direction (the direction of the arrow α in FIG. 2) when the wave coming from the offshore side is rebounded. The region where the unevenness on the offshore wall surface 20 is alternately repeated has a uniform cross-sectional shape in the horizontal direction or the substantially horizontal direction. The unevenness breaks the wave guided along the offshore wall surface 20 when the wave coming from offshore is rebounded by the offshore wall surface 20 (upper inclined portion 22), and thereby the wave pressure on the offshore wall surface 20 is reduced. Reduce. In the present embodiment, the unevenness is provided in the entire area of the offshore wall surface 20 in the guide direction α (that is, from the lower end to the upper end in the guide direction α of the offshore wall surface 20).

  In addition, this unevenness | corrugation does not need to be provided in the whole region in the guide direction (alpha) of the offshore wall surface 20. FIG. For example, the unevenness is alternated in the entire region of the upper inclined portion 22 (that is, from the deepest position 26 of the depth when viewed from the offshore side to the tip 28 of the portion protruding offshore) in the guide direction α of the offshore wall surface 20. It may be repeated. This range (upper inclined portion 22) is a range in which this wave is likely to travel along the offshore wall surface 20 when the wave is rebounded by the offshore wall surface 20 under various tide level conditions and wave conditions. Therefore, if the unevenness is repeated alternately and continuously in the entire region of the upper inclined portion 22 in the guide direction α, the waves guided along the wall surface 20 collide with the uneven protrusions, and are broken. The wave pressure on the side wall surface 20 can be effectively reduced. However, the unevenness may be provided in a part of the upper inclined portion 22 in the guide direction α of the offshore wall surface 20. In this case, the wave pressure can be reduced in the region where the unevenness on the offshore wall surface 20 is repeated.

  Specifically, the unevenness of the offshore wall surface 20 extends in the horizontal direction, and the surface of a plurality of (in this embodiment, five) ridges 30 arranged in parallel or substantially in parallel with a gap in the guide direction α, and the guide It is demarcated by the bottom face 32 located between the protrusions 30 adjacent to each other in the direction α.

  As shown in FIG. 3, the protrusion 30 extends in the horizontal direction or the substantially horizontal direction so that the cross-sectional shape is rectangular and the width dimension in the guide direction α is constant. That is, the protrusion 30 has a uniform cross-sectional shape in the horizontal direction or the substantially horizontal direction. The ridges 30 of the present embodiment are continuous from one horizontal end to the other end on the offshore wall surface 20. The surface of the ridge 30 is composed of a pair of upstanding surfaces 34a and 34b orthogonal to the guide direction α and a top surface 36 that connects the protruding end portions of the pair of upstanding surfaces 34a and 34b. . Of the pair of standing surfaces 34a and 34b, the standing surface (orthogonal surface) 34a facing the guiding direction α collides with the wave guided along the offshore wall surface 20 and breaks this wave.

  The bottom surface 32 is positioned between the standing surfaces 34a and 34b facing each other in the ridges 30 and 30 adjacent to each other in the guide direction α, and extends in the horizontal direction or the substantially horizontal direction so that the width dimension in the guide direction α is constant. Surface. The bottom surface 32 of the present embodiment is a smooth surface along the guide direction α.

  Hereinafter, the distance between the pair of upstanding surfaces 34a and 34b in one protrusion 30 is referred to as the protrusion width B, and the distance from the bottom surface 32 to the top surface 36 (specifically, orthogonal to the guide direction α and orthogonal to the horizontal direction). (Distance in the direction in which the ridges are formed) is referred to as the ridge height H, and the distance between the upstanding surfaces 34a, 34b between the adjacent ridges 30 is referred to as a bottom surface width D (see FIG. 3).

  Each of the ridge height H, the ridge width B, and the bottom surface width D on the offshore wall surface 20 greatly affects the wave pressure reduction performance on the offshore wall surface 20. For example, if the bottom surface width D is too narrow, the wave does not enter the bottom surface portion 32 and the wave travels along the top surface 36 of the ridge 30 so that it does not collapse so much and the wave pressure on the offshore wall surface 20 does not decrease so much. Moreover, when the protrusion height H is too low, the guided wave does not collapse so much and the wave pressure on the offshore wall surface 20 does not decrease so much. Therefore, each value of the ridge height H, the ridge width B, and the bottom surface width D is appropriately set based on the tide level condition, the wave condition, and the like of the place where the wave-proof structure is installed.

  In the offshore wall surface 20 of this embodiment, each value is set so that the ridge width B is larger than the ridge height H and the bottom surface width D is larger than the ridge height H. In this way, on the offshore wall surface 20 of the present embodiment, the guided wave enters the bottom surface 32 so that the bottom surface width D is larger than the ridge height H, and this wave rises up the ridge 30. It is sure to collide with the entire 34a. Specifically, the protrusion height H of the protrusion 30 on the offshore wall surface 20 is 10 cm, the protrusion width B is 40 cm, and the bottom face width D is 40 cm. The wave-breaking structure 10 according to the present embodiment has a top end height of 4 m, a horizontal length of 4 m, and a horizontal distance from the tip 28 on the offshore side wall surface 20 to the deepest position 26 in the depth ( 2D) is 2 m.

  Such a wave preventing structure 10 is formed of reinforced concrete. Specifically, the wave preventing structure 10 is manufactured as follows.

  First, a steel frame, a metal bar, or the like is assembled into a predetermined shape to form a framework. The frame is surrounded by a predetermined formwork. And concrete is poured in this formwork, and the wave-proof structure 10 is formed when this concrete hardens | cures. In this case, the concavo-convex shape of the offshore wall surface 20 is formed integrally with the other part by the framework and the mold surrounding the frame.

  In addition, the specific manufacturing method of the wave-proof structure 10 is not limited to this. For example, a wave-breaking structure having a curved surface (offshore wall surface) having no irregularities, such as the conventional wave-breaking structure shown in FIG. 13, may be formed, and a protrusion may be formed later. Specifically, in the curved surface, the concrete at the portion where the protrusion is formed is pulled. Reinforcing bars, anchor bolts, and the like are driven into the hung portion, and then a mold for forming the ridge is assembled. When the concrete is poured into the mold and solidified, the unevenness is formed on the offshore wall surface. Moreover, you may make it adhere an uneven | corrugated shaped member to the curved surface without an unevenness | corrugation.

  According to the wave-breaking structure 10 as described above, the offshore wall surface 20 has a shape protruding to the offshore side, so that waves arriving on the offshore wall surface 20 from the offshore side are rebounded to the offshore side, Overtopping can be reduced. Moreover, when the waves are repelled by the offshore wall surface 20, the waves guided along the wall surface 20 collide one after another with a plurality of ridges 30 arranged in parallel or substantially parallel to the traveling direction (guide direction α). And thereby, the wave pressure on the offshore wall surface 20 can be reduced.

  Further, since each ridge 30 continuously extends from one end in the horizontal direction to the other end on the offshore wall surface 20, the wave pressure is effectively reduced in the entire horizontal region of the offshore wall surface 20. .

  Moreover, the reduction of the wave pressure with respect to the offshore wall surface 20 is performed more effectively because each protrusion 30 has the upright surface 34a. That is, since the standing surface 34a is a surface orthogonal to the traveling direction α of the wave guided along the offshore wall surface 20, the wave hitting the standing surface 34a can be effectively broken.

  In addition, the wave-proof structure of this invention is not limited to the said embodiment, Of course, a various change can be added in the range which does not deviate from the summary of this invention.

  The specific shape of the ridge 30 is not limited. For example, as shown in FIG. 3, the ridge 30 of this embodiment has a rectangular cross-sectional shape, but as shown in FIG. It may be a ridge 30A. In this case, the area of the rising surface 134a where the waves guided along the offshore wall surface 20 collide is reduced, but the corners can be prevented from being lost. Further, as shown in FIGS. 4B and 4C, the standing surfaces 234a and 334a of the ridges 30B and 30C may not be orthogonal to the wave guiding direction α. In this way, the upright surfaces 234a and 334a facing the guide direction α are inclined with respect to the guide direction α so that the front end side in the protruding direction is rearward, so that the upright surfaces 234a when the waves hit the ridges 30B and 30C. , 334a is reduced, and the ridges 30B and 30C are hardly damaged. Further, there may not be a flat surface (standing surface) at a site where waves guided to the offshore wall surface 20 collide. That is, as shown in FIG. 4D, the surface of the ridge 30D where the wave collides may be curved. Even if it is such a shape, if a wave is guided along the offshore wall surface 20, this wave will be destroyed by colliding with each protrusion 30D, and, thereby, the wave pressure with respect to the offshore wall surface 20 will be reduced.

  In this embodiment, since the cross-sectional shape of the protrusion 30 is rectangular, the bottom surface 32 is required between the protrusions 30 and 30 adjacent to each other in the guide direction α, but the bottom surface 32 is not required depending on the uneven shape. That is, if the projections and depressions are repeated along the guide direction α and have a uniform cross-sectional shape in the horizontal direction, for example, offshore surfaces 20A and 20B shown in FIGS. 5A and 5B. It may be a simple shape. Specifically, like the offshore side wall surface 20A of FIG. 5A, there may be no shape that rises rapidly so as to form an upright surface, and the shape may be unevenly repeated. Even with such irregularities, the wave guided to the offshore wall surface 20A collides with the convex portion 50A one after another in the guiding direction α and is broken, so that the wave pressure on the offshore wall surface 20A can be reduced. Further, as shown in the offshore wall surface 20B of FIG. 5B, the shape may be such that the height gradually decreases from the portion where the convex portion 50B is received toward the next convex portion 50B. Even with such irregularities, the wave guided to the offshore wall surface 20B can successively hit the convex portion 50B in the guiding direction α, thereby breaking the wave and reducing the wave pressure on the offshore wall surface 20B. Is done. In particular, as shown in the offshore wall surface 20B shown in FIG. 5B, the surface may be uneven so that orthogonal surfaces (standing surfaces 34a) orthogonal to or substantially orthogonal to the guide direction α are arranged at predetermined intervals in the guide direction α. For example, even if there is no bottom surface 32, the guided wave can be effectively broken in the same manner as the offshore wall surface 20 provided with the rectangular ridges 30 of the present embodiment, whereby the wave against the offshore wall surface 20B can be broken. The pressure can be effectively reduced. Further, in the offshore wall surface 20B, the top (corner) of the convex portion 50B is more likely to be chipped due to a collision with a wave as compared with other parts. Good (see broken line in FIG. 5B).

  The ridge of the offshore wall surface does not have to be straight in the horizontal direction or the substantially horizontal direction as in this embodiment. For example, like the offshore wall surface 20C shown in FIG. 6 (A), the protrusion 30E may be bent so as to wave.

  Further, as shown in FIG. 6B, the protrusion 30F on the offshore wall surface 20D may be inclined with respect to the horizontal direction. In this case, if the angle of inclination of each protrusion 30F with respect to the horizontal direction is less than 45 °, the wave that is guided and rebounded by the offshore wall surface 20D can be effectively broken.

  The convex portion of the offshore wall surface may not be the ridge 30 that is continuous in the horizontal direction as in the present embodiment. For example, it may be a protrusion intermittent in the horizontal direction, and a plurality of protrusions 50 arranged at intervals in the horizontal direction or the substantially horizontal direction as shown in FIGS. 7 (A) and 7 (B). It may be. Even if it is such a shape, the wave guided to the offshore wall surfaces 20E and 20F can collide with these protrusions 50 to break the wave.

  The region where the unevenness is repeated in the guide direction α in the horizontal direction of the offshore wall surface does not have to be formed in the entire horizontal direction (that is, from one end to the other end in the horizontal direction) as in this embodiment. When the upper end side is viewed along the wall surface from the lower end of the side wall surface (in the direction of arrow β in FIG. 7A), if unevenness is formed in a range of 50% or more in the horizontal direction of the offshore wall surface. Good. If irregularities are formed in such a range, it is possible to effectively reduce the wave pressure on the entire offshore wall surface.

  Further, the offshore wall surface does not have to include both the upper inclined portion and the lower inclined portion, and as shown in FIG. 8, the portion protruding from the offshore side to the upper side of the offshore wall surface 20G (upper inclined portion 22). If it is provided, the waves coming from offshore can be repelled to effectively prevent overtopping. In this case, unevenness may be provided in the entire region of the offshore wall surface 20G in the guide direction α, or may be provided in the entire region of the upper inclined portion 22 in the guide direction α as shown in FIG. Even in the offshore wall surface 20G without the lower inclined portion, if at least a part of the upper inclined portion 22 is uneven, it is possible to reduce the wave pressure on the offshore wall surface 20G at that portion.

In order to confirm the effect of reducing the wave pressure due to the unevenness of the offshore wall surface in the wavebreaking structure of the above embodiment, a scaled 1/20 wavebreak model (offshore wall surface height 14 cm, model overall height 16 cm) A hydraulic experiment using a two-dimensional wave tank was made. In the following experiment, the slope of the seabed on the front side (offshore side) of the wave-breaking structure was 1/10, and the installation depth of the wave-breaking structure model was 11 cm.
<Experiment 1>
The protrusion width B is 20 mm (local conversion: 40 cm), and the protrusion height H is 1.5 mm, 3 mm, 5 mm, 7.5 mm, 10 mm, 12.5 mm (local conversion: 3 cm, 6 cm, 10 cm, 15 cm, 20 cm, 25 cm), and various models with a ratio of the bottom face width D to the ridge width B and D / B of 1 were prepared, and a wave pressure measurement experiment was performed. The small wave pressure gauge was attached to the central part of the guiding direction on the offshore wall surface in the wave-breaking structure model. In addition, it experimented also with the wave-breaking structure model which has the offshore wall surface which consists of a smooth curved surface without an unevenness | corrugation as a reference model.

  The wave pressure is measured by applying a regular wave with a wave height of 10 cm and a period of 1 second (on-site conversion: wave height of 2 m, period of 4.47 seconds) to each wave-breaking structure model, and the average of the offshore wall surface of the wave-breaking structure Wave pressure was calculated.

  The results are shown in Table 1 below and FIGS. 9 and 10.

図９に示すグラフは、横軸を現地換算した突条高さＨとし、縦軸を波圧低減率としている。この波圧低減率は、凹凸を有する沖側壁面における波圧が凹凸なしの沖側壁面における波圧と同じ場合を１としている。図９に示されるように、突条高さＨが１０〜１５ｃｍのときに波圧低減率が最も小さくなり、突条高さＨがそれよりも低くなっても高くなっても波圧低減率が増加する。この結果から、波圧低減率が０．８以下の効果的な範囲（有意な範囲）は、突条高さＨが５〜２０ｃｍの範囲であることがわかった。

In the graph shown in FIG. 9, the horizontal axis is the ridge height H converted in the field, and the vertical axis is the wave pressure reduction rate. The wave pressure reduction rate is set to 1 when the wave pressure on the offshore wall surface having unevenness is the same as the wave pressure on the offshore wall surface without unevenness. As shown in FIG. 9, the wave pressure reduction rate is the smallest when the ridge height H is 10 to 15 cm, and the wave pressure reduction rate even when the ridge height H is lower or higher. Will increase. From this result, it was found that the effective range (significant range) in which the wave pressure reduction rate is 0.8 or less is a range in which the protrusion height H is 5 to 20 cm.

The graph shown in FIG. 10 is a summary of the experimental results in Table 1, with the horizontal axis being the ratio of the protrusion width B to the protrusion height H, B / H, and the vertical axis being the wave pressure reduction rate. From this result, it was found that the effective range (significant range) where the wave pressure reduction rate is 0.8 or less is the range where B / H is 2-8.
<Experiment 2>
Next, the ridge width B is 20 mm (local conversion: 40 cm), the ridge height H is 5 mm (local conversion: 10 cm), and the bottom width D is 10 mm, 15 mm, 20 mm, 25 mm, 30 mm (local conversion: 20 cm, 30 cm). , 40 cm, 50 cm, and 60 cm) were prepared, and wave pressure measurement experiments were performed. Similar to Experiment 1, the small wave pressure gauge was attached to the central portion of the offshore wall surface in the guiding direction in the wave-proof structure model. In addition, as in Experiment 1, the experiment was conducted using a wave-breaking structure model on the offshore wall surface, which is a smooth curved surface without unevenness, as a reference model.

  Wave pressure was measured by applying a regular wave with a wave height of 10 cm and a period of 1 second (on-site conversion: wave height of 2 m, period of 4.47 seconds) to these models, and the average wave pressure on the offshore wall surface of the breakwater structure was calculated. .

  The results are shown in Table 2 below and FIG.

図１１に示すグラフは、横軸を突条幅Ｂに対する底面幅Ｄの比、Ｄ／Ｂとし、縦軸を波圧低減率としている。この波圧低減率は、凹凸を有する沖側壁面における波圧が凹凸なしの沖側壁面における波圧と同じ場合を１としている。図１１に示されるように、Ｄ／Ｂが１のときに波圧低減率が最も小さくなり、Ｄ／Ｂがそれよりも小さくなっても大きくなっても波圧低減率が増加する。この結果から、波圧低減率が０．８以下の効果的な範囲（有意な範囲）はＤ／Ｂが０．７〜１．５の範囲であることがわかった。

In the graph shown in FIG. 11, the horizontal axis is the ratio of the bottom surface width D to the ridge width B, D / B, and the vertical axis is the wave pressure reduction rate. The wave pressure reduction rate is set to 1 when the wave pressure on the offshore wall surface having unevenness is the same as the wave pressure on the offshore wall surface without unevenness. As shown in FIG. 11, the wave pressure reduction rate becomes the smallest when D / B is 1, and the wave pressure reduction rate increases even when D / B becomes smaller or larger. From this result, it was found that the effective range (significant range) in which the wave pressure reduction rate is 0.8 or less is the range where D / B is 0.7 to 1.5.

10 Wave-breaking structure 20 Offshore wall surface 22 Upper inclined part (portion protruding from the deepest part of the depth when viewed from the offshore side in the guide direction of the offshore wall surface)
24 Lower inclined portion 30 ridge 32 bottom surface B ridge width D bottom surface width H ridge height S still water surface W wave α rebounding wave guiding direction

Claims (8)

It is a wave-breaking structure that is erected facing offshore,
It has an offshore wall surface that has a shape protruding to the offshore so that waves coming from the offshore are repelled at the top,
The offshore wall surface has irregularities that are alternately repeated along the guide direction of the wave when the wave rebounds, and the unevenness is a depth as viewed from the offshore side in the guide direction of the offshore wall surface. A wave-breaking structure characterized in that it is provided in at least a part of a portion protruding from the deepest side to the offshore side. In the wave preventing structure according to claim 1,
The wave preventing structure is characterized in that the unevenness is alternately repeated over the entire area of the portion protruding from the deepest depth when viewed from the offshore side in the guide direction of the offshore wall surface. In the wave-breaking structure according to claim 1 or 2,
The region where the unevenness on the offshore wall surface is alternately repeated exists in a range of 50% or more in the horizontal direction of the offshore wall surface when the upper end side is viewed along the wall surface from the lower end of the offshore wall surface. Wave-proof structure characterized by In the wave-breaking structure according to any one of claims 1 to 3,
The wave-breaking structure characterized in that the region where the irregularities on the offshore wall surface are alternately repeated has a uniform cross-sectional shape in the horizontal direction or the substantially horizontal direction. In the wave-breaking structure according to claim 4,
In the region where the unevenness on the offshore wall surface is alternately repeated, an orthogonal surface orthogonal to or substantially orthogonal to the traveling direction of the wave guided along the offshore wall surface is formed in a part of the unevenness. Wave-proof structure characterized by In the wave-breaking structure according to any one of claims 1 to 4,
The unevenness of the offshore wall surface extends in a horizontal direction or a substantially horizontal direction, and is formed between a surface of a plurality of ridges arranged in parallel or substantially in parallel with the gap in the guide direction, and ridges adjacent to each other in the guide direction. A wave-breaking structure characterized in that it is defined by a bottom surface located therebetween. In the wave-breaking structure according to claim 6,
The wave preventing structure according to claim 1, wherein the protrusion has an orthogonal surface that is orthogonal or substantially orthogonal to a traveling direction of a wave guided along the offshore wall surface. In the wave-breaking structure according to claim 6 or 7,
A wave-breaking structure characterized in that a width dimension of the bottom surface in the guide direction is larger than a height dimension of the protrusion in a direction perpendicular to the guide direction and perpendicular to the horizontal direction.

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