JP5322068B1 - Construction method of submarine - Google Patents

Abstract

A submerged dike that can maintain its function even under a tsunami flowHow to buildI will provide a.
[Solution] After the side lower frame 15 is installed on the rubble mound so that the horizontal direction in which the water flow permeable planar member 20 extends is substantially orthogonal to the direction in which the assumed tsunami flow proceeds, the side lower frame 15 The inside packing stone 16 is inserted from above so as not to pass through the water flow permeable planar member 20, and further rubble is laid on the rubble mound. The bottom lower side of the side lower frame 15 is covered with rubble so as to be rooted, and further, the inserted side clogging stone 16 does not come out from the upper side of the side lower frame 15, The upper part of the frame 15 is covered with a water flow permeable lid member 24.
[Selection] Figure8

Description

The present invention relates to a method for constructing a latent Tsutsumi, in particular, the method relates to the construction of the latent bank that can be maintained function receives the tsunami flow.

  The great tsunami caused by the 2011 off the Pacific coast of Tohoku Earthquake that occurred on March 11, 2011 caused devastating damage to the Pacific coast of the Tohoku and Kanto regions, but Kamaishi and Ofunato in Iwate Prefecture were no exception. Then the Wangkou breakwater collapsed and suffered great damage.

  The tsunami breakwater at Kamaishi Port is located at the entrance of the port, with an opening (extension 300m), a 670m breakwater (south bank) on the south side, and a 990m breakwater (north bank) on the north side. Furthermore, the opening (extension 300 m) is provided with a submerged dam that extends from the sea floor to a depth of -19 m (for example, see Non-Patent Document 1).

  The tsunami breakwater at Kamaishi Port was damaged not only by the north and south breakwaters but also at the opening (extension: 300m) due to the Tohoku Pacific Ocean Earthquake. The fast tsunami flow and pressure caused the caisson to slide on the rubble mound and fall from the rubble mound.

“Examination of damage factors of Kamaishi Port Tsunami Breakwater caused by Tohoku Pacific Ocean Earthquake Tsunami”, Port and Airport Research Institute, April 1, 2011 Attachment 3 of “Verification of process” (April 1, 2011)

The present invention was made in view of such damage status, and to provide a method for constructing a latent bank where Ru can remain functional even when subjected to tsunami flow.

This invention solves the said subject with the construction method of the following submerged dike.

  A first aspect of the submerged dike construction method according to the present invention is a submerged dike construction method in which a frame is installed on the rubble mound so that at least a part thereof is embedded in the rubble mound. And having a plurality of water permeable planar members facing each other, and a plurality of walls substantially orthogonal to the horizontal direction in which the water permeable planar members extend in a state of being installed on the rubble mound. It has a closed shape in a horizontal plane when viewed from above when installed on the rubble mound, and further has a water-permeable bottom member at the bottom when installed on the rubble mound. In addition, a lateral lower frame that is open at the top is installed on the rubble mound so that the horizontal direction in which the water flow permeable planar member extends is substantially perpendicular to the direction in which the assumed tsunami flow proceeds. Thereafter, inside the side lower frame, a filling stone is inserted from above so as not to pass through the water-permeable planar member, and further, a rubble is laid on the rubble mound, and the filling is inserted. The bottom of the side lower frame is covered with stones and the laid rubble, and is further embedded, and further, the side clogging stone is prevented from coming out from the upper part of the side lower frame. It is a construction method of a submerged dike characterized in that the upper part of the lower frame is covered with a water-permeable cover member.

  Among the filling stones that are put into the inside of the lateral lower frame, the filling stones that are put into a portion in contact with the water flow permeable planar member have a size that does not pass through the water flow permeable planar member. It is preferable that the medium packing stone to be introduced into a portion in contact with the water flow permeable lid member has a size that does not pass through the water flow permeable lid member.

  In addition, although the upper part of the side lower frame used in the first aspect of the construction method of the submerged dike according to the present invention is open, the "open" here is not only in a completely open state, This is a concept including a state in which, for example, a bar-like member is disposed on the inner upper portion of the side lower frame if there is a gap inside the side lower frame to allow the filling stone to be inserted from above.

  The second aspect of the submerged dike construction method according to the present invention is a submerged dike construction method in which a frame is installed on the rubble mound so that at least a part thereof is embedded in the rubble mound. And having a plurality of water permeable planar members facing each other, and a plurality of walls substantially orthogonal to the horizontal direction in which the water permeable planar members extend in a state of being installed on the rubble mound. It has a closed shape in a horizontal plane when viewed from above in the state installed on the rubble mound, and a side frame opened at the top in the state installed on the rubble mound, After the horizontal direction in which the water flow permeable planar member extends is set on the rubble mound so as to be substantially orthogonal to the direction in which the assumed tsunami flow proceeds, the filling stone is placed inside the side frame. While thrown from above so as not to pass through the flow permeable planar member, laying further rubble on the rubble mound, around the lower portion of the side frame by the stuffed stone and laid rubble Further, the upper portion of the side frame is covered with a water-permeable lid member so that the inserted cobblestone does not come out from the upper portion of the side frame. It is a construction method of a submarine.

  Among the filling stones to be put inside the side frame, it is preferable that the filling stones to be put into a portion in contact with the water flow permeable planar member has a size that does not pass through the water flow permeable planar member. It is preferable that the medium packing stone to be introduced into the portion in contact with the water flow permeable lid member has a size that does not pass through the water flow permeable lid member.

  In addition, although the upper part of the side frame used in the second aspect of the construction method of the submerged dike according to the present invention is open, the “open” here is not only in a completely open state, This is a concept that includes a state in which, for example, a bar-like member is disposed on the inner upper portion of the side frame, as long as there is a gap inside the side frame in which the filling stone can be inserted from above.

In the construction method of the submerged levee, the filling stone may be thrown into the inside of the frame by a shooter.
The submerged dike that can be constructed using the first aspect of the submerged dike building method according to the present invention includes, for example, a rubble mound built on the seabed, and at least a part of the rubble mound being rooted in the rubble mound. A submerged dike, and the frame has a plurality of water permeable planar members facing each other and a horizontal direction in which the water permeable planar member extends. A plurality of substantially perpendicular wall members, a top portion having a water flow permeable lid member, and a bottom portion having a water flow permeable bottom member, the plurality of water flow permeable planar members, A wall surrounded by the water flow permeable lid member and the water flow permeable bottom member on the side, upper and lower sides, and the frame extends from the water permeable planar member. Horizontal direction is expected tsunami flow Is disposed in the rubble mound so as to be substantially orthogonal to the direction in which the water flow is permeable, and in the space surrounded by the side, upper and lower sides, the clogged stone is the water flow permeable planar member and the water flow permeable lid member. It is a submerged dike that is filled so as not to pass through.
In addition, in this application, the covering stone which covers the surface layer part of a rubble mound is also made into a part of a rubble mound.
The “frame integrated with the rubble mound” is a fixed frame in which the position of the frame does not move even if the pressure of the assumed tsunami current acts on the submerged dam if the rubble mound does not collapse. That is.
In addition, the “water flow permeable planar member” is a planar member that can permeate a water flow in a direction perpendicular to the surface. And a lattice-shaped member in which rod-like members are arranged at predetermined intervals in both the vertical and horizontal directions inside a rectangular frame member.
Further, “having a plurality of water permeable planar members facing each other” naturally includes a case where a plurality of water permeable planar members are parallel to each other, but is not limited to this, The state which can say that the transparent planar member is facing generally is also included. For example, when the shape when the frame is viewed from a horizontal direction substantially orthogonal to the direction in which the assumed tsunami flow proceeds (the shape when the wall body is viewed from the front) is an isosceles trapezoid, Both the offshore side and the land side surface (water flow permeable planar member) are included in the category of “facing”.
In addition, the term “wall body” as used herein includes the concept of including a planar member including a through-hole on a wall surface, for example, a planar member formed by assembling a rod-shaped member in a truss structure. This is a concept that includes a ratio of the area of the through-holes to the total area) when the member has no through-holes, for example, 90% or more.
Among the filling stones filled in the space surrounded by the side, upper, and lower sides, the filling stones filled in the portion in contact with the water flow permeable planar member are the water permeable planar members. It is preferable that the size does not pass, and it is preferable that the filling stone filled in the portion in contact with the water flow permeable lid member does not pass through the water flow permeable lid member.
The submerged dike that can be constructed using the second aspect of the method of constructing a submerged dike according to the present invention includes, for example, a rubble mound built on the seabed, and at least a part of the rubble mound being rooted in the rubble mound. A submerged dike, and the frame has a plurality of water permeable planar members facing each other and a horizontal direction in which the water permeable planar member extends. A plurality of wall bodies that are substantially orthogonal to each other, and further have a water flow permeable lid member at the top, and the plurality of water flow permeable planar members, the plurality of wall bodies, and the water flow permeable lid member. The frame has a space surrounded by a side and an upper side, and the frame includes the rubble mound so that a horizontal direction in which the water flow permeable planar member extends is substantially orthogonal to a direction in which an assumed tsunami flow proceeds. Are located in The said space surrounded the rectangular and upward a latent bank, wherein a middle pallet is filled so as not to pass through the water-permeable surface member and the water flow-permeable cover member.
Among the filling stones filled in the space surrounded by the sides and above, the filling stones filled in the portion in contact with the water flow permeable planar member do not pass through the water flow permeable planar member. It is preferable that the medium packing stone filled in the portion in contact with the water flow permeable lid member has a size that does not pass through the water flow permeable lid member.
The shape of the wall body when viewed from the horizontal direction in which the water flow permeable planar member extends is preferably a substantially isosceles trapezoid whose base is longer than the top.
The wall body includes, for example, at least a rod-shaped member disposed substantially parallel to a direction in which an assumed tsunami flow proceeds and a rod-shaped member disposed in a substantially vertical direction and embedded in the rubble mound. You may comprise as follows.
Further, the member constituting the wall body may be a rod-shaped member, and the wall body may be formed by a truss structure.
The water flow permeable planar member may be configured to have a plurality of rod-like members arranged at predetermined intervals.
The frame is preferably made of steel. However, it is also possible to use a rod-shaped member made of reinforced concrete (RC) or a rod-shaped member made of a composite structure of steel and concrete (such as an SRC structure).
Moreover, it is preferable that the member which comprises the said wall body is a steel pipe with which concrete is filled inside.
Further, the member constituting the water flow permeable planar member may include a section steel.

A submerged dike that can be constructed using the method of constructing a submerged dike according to the present invention comprises a frame that is at least partially embedded in a rubble mound and integrated with the rubble mound. Since the filling stone is filled so as not to pass through the conductive surface member and the water flow permeable lid member, the function can be maintained even if the tsunami flow is received.

The perspective view of an example of the submerged dike which can be constructed | assembled using the construction method of the submerged dike which concerns on embodiment of this invention. Front view of the water flow permeable planar member 20 in the submerged dike Front view of wall body 22 in the submerged dike Front view of wall body 32 in modified example 1 of the submerged levee Front view of the water-permeable cover member 24 in the submerged dike Front view of water-permeable bottom member 26 in the submerged dike Front view of wall 34 in modified example 2 of the submerged dike The figure which shows typically an example of the construction condition in the construction method of the submerged dike which concerns on embodiment of this invention

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(1) Configuration FIG. 1 is a perspective view showing an example of a submerged dike that can be constructed using a submerged dike construction method according to an embodiment of the present invention.

A submerged dike 10 (hereinafter simply referred to as “ submerged dike 10 according to this embodiment”) that can be constructed using the submerged dike construction method according to the present embodiment is a rubble mound 12 and a steel frame. 14 and a filling stone 16, and a structure in which a steel frame 14 is installed on the rubble mound 12 so as to be at least partially embedded in the rubble mound 12. This is a structure in which the inside packing stone 16 is filled. In the submerged dike 10 according to the present embodiment , a structural part including the steel frame 14 and the medium packing stone 16 is referred to as a main body structural part 18. Moreover, below, the state in which the steel frame 14 is installed on the rubble mound 12 so that at least a part of the rubble mound 12 is embedded may be referred to as “the state in which the steel frame 14 is installed”. .

  The rubble mound 12 is built on the seabed, and in the same way as a normal rubble mound, it plays the role of correcting the unevenness of the foundation ground to stabilize the structure, and distributing the load of the structure evenly to the ground. It has the role of absorbing the wave force acting on the structure by the frictional force between the inside of the rubble mound 12 and the foundation ground (sea floor), the role of preventing the scouring of the ground at the bottom of the structure due to waves and tidal currents, and the like. The rubble mound 12 is covered with a covering stone in the same manner as a normal rubble mound, but in FIG. 1, the rubble mound and the covering stone are similarly drawn without being distinguished.

  The rubble and covering stone used for the rubble mound 12 of the submerged dike 10 according to the present embodiment are not particularly limited, and the same rubble and covering stone used for a normal rubble mound can be used.

  The steel frame 14 includes a water-permeable planar member 20, a wall body 22, a water-permeable lid member 24, and a water-permeable bottom member 26, and a plurality of water-permeable planar members. 20 are provided so as to face each other, and when installed on the rubble mound 12, a plurality of wall bodies 22 that are substantially orthogonal to the horizontal direction in which the water flow permeable planar member 20 extends are provided. A water-permeable bottom member 26 at the bottom, a plurality of water-permeable planar members 20, a plurality of wall bodies 22, a water-permeable lid member 24, and a water-permeable A space 28 surrounded by the bottom member 26 on the side, upper side, and lower side is provided, and the inner side (the space 28) of the steel frame 14 is filled with the filling stone 16. More specifically, a portion in contact with the water flow permeable planar member 20 is filled with medium packing stone 16 having a size that cannot pass through the water permeable planar member 20, and a portion in contact with the water permeable lid member 24 is filled with water flow. Filling stones 16 of a size that cannot pass through the permeable lid member 24 are filled.

  Further, the steel frame 14 is disposed on the rubble mound 12 so that the horizontal direction in which the water flow permeable planar member 20 extends in a state where the steel frame 14 is installed on the rubble mound 12 is substantially orthogonal to the direction in which the assumed tsunami flow proceeds. The wall 22 is arranged so as to be substantially parallel to the direction in which the assumed tsunami flow proceeds.

  The shape (the shape of the side surface (wall body 22) of the steel frame 14) when the steel frame 14 is viewed from the horizontal direction orthogonal to the direction in which the assumed tsunami flow proceeds is substantially equal as shown in FIG. It is a leg trapezoid.

  Moreover, as will be described later, the lower part of the side steel pipe 60 and the vertical steel pipe 62 (see FIG. 3) of the wall body 22 is surrounded by the filling stone 16 and the rubble, and is embedded in the rubble mound 12, Thereby, the steel frame 14 is integrated with the rubble mound 12.

  The medium packing stone 16 is filled in the inside (space 28) of the steel frame 14 and becomes a main structural portion (a part of the main body structural portion 18) of the submerged dam 10 according to the present embodiment, and functions as a submerged levee. Have the role of

  The type of stone used as the medium packing stone 16 is not particularly limited, but the medium packing stone 16 at a position in contact with the water flow permeable planar member 20 is preferably sized so as not to pass through the water permeable planar member 20. The medium packing stone 16 at a position in contact with the water flow permeable lid member 24 is preferably sized so as not to pass through the water flow permeable lid member 24.

  However, as a general rule, all the filling stones 16 filled inside the steel frame 14 cannot be passed through the water-permeable planar member 20 and the water-permeable lid member 24 and are positioned at the inside of the steel frame 14. Accordingly, it is more advantageous in terms of workability to eliminate the need to use different medium-filled stones 16 having different sizes.

  In addition, even if the size of the individual medium packing stones 16 at the position in contact with the water flow permeable planar member 20 is large enough to pass through the water flow permeable planar member 20, the arch effect by the plurality of medium packing stones 16 is provided. Therefore, the size of the clogging stone 16 at the position in contact with the water flow permeable planar member 20 is set so that it cannot pass through the water permeable planar member 20. Aligning is not always necessary in some situations.

  Similarly, even if the size of each of the medium packing stones 16 in contact with the water flow permeable lid member 24 is large enough to pass through the water flow permeable lid member 24, the arch effect of the plurality of medium packing stones 16 causes Since it is also possible that the water-permeable lid member 24 cannot pass, it is a situation that the size of the filling stone 16 at the position in contact with the water-permeable lid member 24 is made all the sizes that cannot pass the water-permeable lid member 24. It is not always necessary.

  FIG. 2 is a front view of the water permeable planar member 20 (view of the water permeable planar member 20 from a direction orthogonal to the surface formed by the water permeable planar member 20). As shown in FIG. 2, the water flow permeable planar member 20 includes a steel pipe 50, a shaped steel 52, and a round steel 54, and has a role of restraining the stacked filling stones 16 so as not to collapse.

  The steel pipes 50 arranged in the vertical direction are members common to the side members (the side steel pipes 60 shown in FIG. 3) of the isosceles trapezoidal wall body 22, and the lower part is embedded in the rubble mound 12. In addition, five section steels 52 are arranged in the horizontal direction at approximately equal intervals between the two steel pipes 50, and further, six round bars 54 are provided between the two steel pipes 50 in parallel with the steel pipe 50. Are arranged in the vertical direction at approximately equal intervals.

  Filling the steel pipe 50 with concrete makes the steel pipe 50 filled with concrete because it becomes strong against impacts when the medium packing stone 16 is put inside the steel frame 14 and the steel material is hardly damaged. It is preferable. However, it is not necessarily impossible to use a shape steel in place of the steel pipe 50, and it is also possible to use a shape steel in place of the steel pipe 50 after checking safety.

  In FIG. 2, only three steel pipes 50 are depicted, but the number of steel pipes 50 can be arbitrarily increased according to the necessary extension distance of the submerged dam 10.

  The water flow permeable planar member 20 may be a planar member that can permeate the water flow in a direction perpendicular to the surface and has a function of restraining the stacked filling stones 16 from collapsing. As long as this condition is satisfied, the shape and material are not necessarily limited.

  In FIG. 2, the shape steel 52 between the two steel pipes 50 is five and the round steel 54 between the two steel pipes 50 is six. However, these numbers are merely examples, and It is not limited. Further, if it is possible to ensure the function of restraining the inner packing stone 16 so as not to collapse, for example, only the uppermost and lowermost two of the five section steels 52 in FIG. 2 are left, and the other three are It may be omitted. Moreover, a round steel may be used instead of the shape steel 52 in FIG. 2, and a shape steel may be used instead of the round steel 54 in FIG. Moreover, you may make it abbreviate | omit the round steel 54 by increasing the number of the shape steels 52 and making the space | interval between the shape steels 52 small. In this case, round steel may be used instead of the shape steel 52.

  However, considering the impact when the medium packing stone 16 is put inside the steel frame 14, the material of the water flow permeable planar member 20 is preferably a material having excellent toughness, and the water permeable planar member 20 has a steel material. Is preferably used. In particular, since the member embedded in the rubble mound 12 is important for ensuring the stability of the main body structure portion 18, it is preferable to use a steel pipe as described above and to fill the steel pipe with concrete. .

  FIG. 3 is a front view of the wall body 22 (a view of the wall body 22 viewed from a direction orthogonal to the surface formed by the wall body 22). As shown in FIG. 3, the wall body 22 includes a side steel pipe 60 (common to the steel pipe 50 of the water flow permeable planar member 20), a vertical steel pipe 62, a horizontal steel pipe 64, and a brace steel pipe 66. These steel pipes form a truss structure, and the shape of the wall 22 viewed from the front is a substantially isosceles trapezoid. Further, the lower part of the side steel pipe 60 and the vertical steel pipe 62 is covered with the crushing stone 16 and the rubble and surrounded by the rubble mound 12 so that the steel frame 14 is integrated with the rubble mound 12. Yes. Furthermore, the surface formed by the wall body 22 (a plane including all of the side steel pipe 60, the vertical steel pipe 62, the horizontal steel pipe 64, and the brace steel pipe 66) is parallel to the direction in which the tsunami flow proceeds, The steel frame 14 is arranged on the rubble mound 12 and is arranged so that it can resist the tsunami flow from offshore by the truss structure of the wall 22.

  Therefore, the wall body 22 can maintain the position and shape even when it receives a tsunami flow, and the wall body 22 can be moved or collapsed with respect to the tsunami flow. It has a role to prevent.

  Thus, the wall body 22 is an important part for ensuring the stability of the main body structure portion 18 against the tsunami flow, and the side steel pipe 60, the vertical steel pipe 62, and the horizontal steel pipe 64 that constitute the wall body 22. The brace steel pipe 66 is preferably filled with concrete, and it is preferable that the brace steel pipe 66 is made strong against an impact when the filling stone 16 is put inside the steel frame 14. Moreover, by using a steel pipe, the cross-sectional efficiency is improved and the anticorrosion area is reduced as compared with the case of using a shape steel. However, it is not possible to use a shaped steel instead of a steel pipe, and it is possible to use a shaped steel instead of a steel pipe after checking safety, or a rod-shaped member made of reinforced concrete (RC) It is also possible to use a rod-shaped member made of a composite structure of steel and concrete (such as an SRC structure).

  Note that the wall body 22 does not necessarily have a truss structure. For example, the wall body 22 may have a ramen structure by rigidly connecting contacts of steel pipes.

In addition, the side steel pipe 60 of the wall body 22 in the submerged dam 10 according to the present embodiment is a straight straight steel pipe, but instead of this, for example, a wall body 32 shown in FIG. Alternatively, a curved steel pipe 68 may be used (Modification 1). In the first modification, the steel pipes other than the curved steel pipe 68 have the same shape and function as the vertical steel pipe 62, horizontal steel pipe 64, and brace steel pipe 66 of the wall body 22, respectively. The steel pipes other than the 32 curved steel pipes 68 are given the same numbers as the corresponding steel pipes of the wall body 22 (see FIG. 3).

  In addition, in the steel frame 14 in the modified example 1, since the wall body 32 having the curved steel pipe 68 curved outwardly is provided, the water flow permeable planar member 20 is adapted to the shape of the curved steel pipe 68. The curved shape is curved outwardly.

  FIG. 5 is a front view of the water-permeable lid member 24 (a view of the water-permeable lid member 24 viewed from a direction orthogonal to the surface formed by the water-permeable lid member 24 (from directly above). In the state shown in FIG. 1, the water-permeable cover member 24 has a shape steel 70 arranged in a horizontal direction (horizontal direction in which an assumed tsunami flow proceeds) orthogonal to the horizontal direction in which the water-permeable planar member 20 extends. , Composed of a shape steel 72 arranged in a horizontal direction orthogonal to the shape steel 70 and a round steel 74 arranged in a horizontal direction parallel to the shape steel 70, and the lift when receiving a fast water flow by a tsunami flow, It has a role to cover the stacked filling stones 16 so as not to be discharged from the upper part of the steel frame 14 to the outside.

  The water flow permeable lid member 24 is capable of transmitting a water flow in a direction perpendicular to the surface, and has a function of covering the stacked filling stones 16 so as not to be discharged to the outside from the upper part of the steel frame 14. It may be a planar member, and the shape and material are not necessarily limited as long as this condition is satisfied.

  In FIG. 5, there are six shape steels 72 between the two shape steels 70 and four round steels 74 between the two shape steels 70, but these numbers are only examples, and The number is not limited. Further, for example, if the function of covering the clogging stone 16 so as not to be discharged from the upper part of the steel frame 14 to the outside can be ensured, for example, the uppermost and lowermost stages of the six structural steels 72 in FIG. Only two may be left and the other four may be omitted. Moreover, a round steel may be used instead of the shape steel 72 in FIG. 5, and a shape steel may be used instead of the round steel 74 in FIG. Moreover, you may make it abbreviate | omit the round steel 74 by increasing the number of the shape steel 72 and making the space | interval between the shape steel 72 small. In this case, round steel may be used instead of the shape steel 72.

  In FIG. 5, three shape steels 70 are drawn per one water-permeable cover member 24, but the number of shape steels 70 is four or more even if two pieces per one water-permeable cover member 24. It is good. However, since the water-permeable lid member 24 is attached by underwater work after the filling of the medium packing stone 16 is completed, attention should be paid so that the size of the water-permeable lid member 24 does not become too large in consideration of workability. .

  FIG. 6 is a front view of the water-permeable bottom member 26 (view of the water-permeable bottom member 26 from a direction orthogonal to the surface formed by the water-permeable bottom member 26 (from directly above). In the state shown in FIG. 1, the water permeable bottom member 26 is a steel pipe 76 (wall) arranged in a horizontal direction (horizontal direction in which an assumed tsunami flow proceeds) orthogonal to the horizontal direction in which the water permeable planar member 20 extends. And a horizontal steel pipe 64 of the body 22) and a steel frame 78 arranged in a horizontal direction orthogonal to the steel pipe 76 (common to the steel plate 52 of the water flow permeable planar member 20). A round steel 80 parallel to the steel pipe 76 and a shape steel 79 parallel to the shape steel 78 are arranged in a grid pattern.

  The water flow permeable bottom member 26 is only required to have a function of fixing the position of the entire steel frame 14 by receiving and fixing the weight of the medium packing stone 16 from above. The shape and material are not necessarily limited.

  In FIG. 6, the round steel 80 and the shaped steel 79 are arranged in a lattice shape in a rectangular frame formed by the steel pipe 76 and the shaped steel 78, but this is an example and is limited to such an arrangement. I don't mean.

  As for the material of the water permeable bottom member 26, considering the impact when the filling stone 16 is put inside the steel frame 14, a material having excellent toughness is preferable, and the water permeable bottom member 26 is made of steel. It is preferable. However, similarly to the water flow permeable planar member 20 and the wall body 22, a rod-like member having a reinforced concrete structure (RC structure) or a composite structure of steel and concrete (such as an SRC structure) can also be used.

  In addition, depending on conditions, such as assumed tsunami flow and the topography to install, the case where the stability of a submerged dike can be ensured without providing the water-flow-permeable bottom member 26 is also considered. As a result of the verification, when it is confirmed that the stability of the submergence can be secured, the water-permeable bottom member 26 may be omitted.

(2) About Characteristic Parts and Effects Although the configuration of the submerged dike 10 according to the present embodiment has been described in the above (1), here, the main features and effects of the submerged dike 10 according to the present embodiment will be focused. This will be explained in more detail.

The first feature of the submerged dike 10 according to the present embodiment is a netting effect in which a part of the steel frame 14 is embedded in the rubble mound 12 and the steel frame 14 and the rubble mound 12 are integrated. Yes, the second feature is a water flow permeation effect that allows the water flow to penetrate through the main body structure portion 18 by using the medium packing stone 16 in the main body structure portion 18, and the third feature is ,
The shape of the wall body 22 when viewed from the front (the shape when the steel frame 14 is viewed from the horizontal direction orthogonal to the direction in which the assumed tsunami flow proceeds) is a substantially isosceles trapezoid, and the main body structure This is an inclination effect due to the fact that the side surfaces on the offshore side and the land side of the portion 18 are inclined surfaces. These three effects will be described in order.

(2-1) Rooting effect As mentioned above, the lower part of the side steel pipe 60 and the vertical steel pipe 62 of the wall 22 is rooted in the rubble mound 12, whereby the steel frame 14 is connected to the rubble mound 12. It is integrated. For this reason, even if the submerged dike 10 which concerns on this embodiment receives a tsunami flow, the function as a submerged dike is easy to be maintained.

  On the other hand, in the conventional structure type in which the caisson is installed on the rubble mound, the function of maintaining the position of the caisson mainly depends on the weight of the caisson. For this reason, the conventional structure with caisson installed on the rubble mound has a weak function of maintaining the position against the tsunami flow. When the tsunami flow is received, the caisson slides on the rubble mound or from the rubble mound. There is a risk that it may fall and become unable to maintain its function as a submerged dike.

  In addition, as a conventional structure, there is a structural form in which a wave-dissipating block is arranged on a rubble mound. In this structural form, the function of maintaining the position of the wave-dissipating block is mainly based on the weight of the wave-dissipating block. For this reason, in the conventional structure type in which the wave-dissipating block is installed on the rubble mound, the function of maintaining the position with respect to the tsunami flow is weak, and when the tsunami flow is received, the wave-dissipating block slides on the rubble mound, There is a risk of falling from the rubble mound and not being able to maintain its function as a submarine.

(2-2) Water Flow Permeation Effect The main body structure portion 18 of the submerged dam 10 according to the present embodiment is configured by filling the inner chamfer 16 inside the steel frame 14, and the inner cuff 16 has a volume. Occupies the majority. As described above, the water flow permeable planar member 20 of the steel frame 14 can transmit the water flow in a direction perpendicular to the surface. Further, in the structure in which the medium packing stones 16 are stacked, there is inevitably a considerable space between the medium packing stones 16 (a space ratio having a considerable volume ratio with respect to the total volume of the main body structure portion 18). Will be.

  For this reason, even if the main body structure portion 18 of the submerged dike 10 according to the present embodiment receives a tsunami flow, it does not receive all the pressure caused by the tsunami flow, and a small proportion of the received tsunami flow is on the opposite side. Permeate (land side).

  Therefore, even if the submerged dike 10 according to the present embodiment receives a tsunami flow, the horizontal force applied to the main body structure portion 18 is smaller than that of the conventional structure type that does not allow the water flow such as caisson. For this reason, even if the submerged dike 10 which concerns on this embodiment receives a tsunami flow, the function as a submerged dike is easy to be maintained.

  Moreover, in the conventional structure type in which caisson is installed on the rubble mound, it is considered that the caisson has a large lift due to the fast water flow caused by the tsunami flow so that the wing of the airplane receives the lift by the air flow.

  On the other hand, since the main body structure portion 18 of the submerged dam 10 according to the present embodiment can considerably pass a water flow in the vertical direction, the main structure portion 18 does not receive a large lift as in the case of caisson.

  Also from this point, the main body structure portion 18 of the submerged dike 10 according to the present embodiment is easy to hold the position even when subjected to a tsunami flow, and even if the submerged dike 10 according to the present embodiment receives a tsunami flow, Easy to maintain the function.

  In the above description, the description has been made with the tsunami flow from the offshore in mind, but the submerged dike 10 according to the present embodiment can also exert the same effect against the pulling wave from the land. .

  As described above, the main body structure portion 18 of the submerged dike 10 according to the present embodiment transmits the tsunami current and the pulling wave from the land to the opposite side to reduce the horizontal force received from the tsunami current and the pulling wave from the land. And the function of generating almost no lift due to the tsunami flow and the rapid water flow caused by the pulling wave from the land. It plays a big role. On the other hand, each of the stuffed stones 16 has a much smaller mass than the conventional caisson, so there is a concern about stability in a place where the flow is fast. However, each of the stuffing stones 16 is much smaller in mass than the conventional caisson, but is gathered as a large block by the steel frame 14, so that the same mass effect as the caisson is exhibited as a whole. In addition, the main body structure portion 18 of the submerged dam 10 according to the present embodiment has stability in a place where the flow is fast from the viewpoint of mass.

(2-3) Inclination Effect In the submerged dike 10 according to the present embodiment, the shape of the steel frame 14 (the shape of the wall 22 viewed from the front) viewed from the horizontal direction in which the water flow permeable planar member 20 extends is as follows. It is substantially isosceles trapezoidal, and the angle formed by the water flow permeable planar member 20 and the horizontal plane is less than 90 °. Therefore, even if it is subjected to a tsunami flow, the water flow can be received to some extent (hereinafter referred to as an inclination). May be described as an effect.).

  On the other hand, in the conventional structural form in which the caisson is installed on the rubble mound, the side surface of the caisson is not inclined and is vertical, and the effect of receiving the tsunami flow like the submerged dam 10 according to the present embodiment is I can't get it.

In addition, since the water flow caused by the tsunami going up the land has a considerable speed, the angle between the water-permeable planar member 20 and the side facing the offshore with the horizontal plane is 90 °. It is preferable that the angle between the side facing the land and the horizontal plane is less than 90 °. That is, the shape when the steel frame 14 is viewed from the horizontal direction orthogonal to the direction in which the assumed tsunami flow proceeds, such as the submerged dike 10 according to the present embodiment (the side surface (wall body 22 of the steel frame 14). )) Is preferably a substantially isosceles trapezoid whose angle between the side and the bottom is less than 90 °.

  In addition, in the submerged dike 10 according to the present embodiment, the effects (1) and (2) as described above can be obtained, so that the strength of the assumed tsunami current, the position where the submerged dike is installed, and the topography Depending on the relationship and the performance required of the submerged dike, it may be possible to ensure safety even if the tilt effect for receiving the tsunami flow is not obtained. In such a case, the angle formed by the water permeable planar member 20 with respect to the horizontal plane does not have to be less than 90 °, and the shape of the steel frame 14 viewed from the horizontal direction in which the water permeable planar member 20 extends ( The shape of the wall viewed from the front may be substantially rectangular, for example (Modification 2).

  FIG. 7 is a front view of the wall body 34 in the second modified example (a view of the wall body 34 viewed from a direction perpendicular to the surface formed by the wall body 34). The wall body 34 is the same as the wall body 22 having a substantially isosceles trapezoidal shape except that the shape is substantially rectangular, and includes a side steel pipe 82, a vertical steel pipe 84, a horizontal steel pipe 86, and a brace steel pipe 88. These steel pipes form a truss structure.

(2-4) Summary As described above in (2-1) to (2-3), the three main features and effects of the submerged dike 10 according to the present embodiment are described. The effect obtained in is significantly superior to the conventional structure type.

  On the other hand, as shown in FIG. 1, the main structure of the submerged dike 10 according to the present embodiment is to install a steel frame 14 on the rubble mound 12 so that at least a part thereof is embedded in the rubble mound 12, The steel frame 14 has a structure in which medium packing stones 16 are filled, and the structure is simple. Moreover, the materials to be used are mainly the rubble of the rubble mound 12 and the medium stuffing stone 16 other than the steel material of the steel frame 14, and are inexpensive.

  Therefore, it can be said that the submerged dike 10 according to the present embodiment is a structural type that is extremely cost-effective.

  In addition, it has been confirmed by the hydraulic experiment that the dike 10 according to the present embodiment has the effects described in (2-1) to (2-3).

(3) About construction procedure Finally, the construction procedure in the construction method of the submerged dike concerning this embodiment is explained. FIG. 8 is a diagram schematically illustrating an example of a construction situation of the submerged dike 10 according to the present embodiment.

  First, a rubble mound is installed on the seabed where the dike 10 is constructed. The steel frame 14 excluding the water flow permeable lid member 24 (a steel frame comprising the water flow permeable planar member 20, the wall 22 and the water flow permeable bottom member 26, hereinafter referred to as a lateral lower frame 15). In order to distinguish the rubble mound before the installation of the crushed stone 10 from the completion of the submerged dam 10, the rubble mound before the installation of the side lower frame 15 will be referred to as the initial rubble mound. . The installation of the initial rubble mound may be performed in accordance with the general method of setting the current rubble mound, and the description thereof will be omitted. However, after the side lower frame 15 is set on the initial rubble mound, the inside lower side frame 15 is filled with the inner packing stone 16, and further, the rubble and the covering stone are set on the initial rubble mound, Since the lower frame 15 is rooted in the rubble mound 12, the initial rubble mound is equivalent to the amount of rubble and covering stones installed on the initial rubble mound after the side lower frame 15 is installed on the initial rubble mound. The amount of rubble is set to be smaller than the rubble mound 12 after the submerged dam 10 is completed.

  After completing the installation of the initial rubble mound on the seabed, the lateral lower frame 15 is installed at a predetermined position of the initial rubble mound using a crane or the like. At this time, it should be noted that the horizontal direction in which the water-permeable planar member 20 extends when viewed from above is installed on the initial rubble mound so that it is substantially orthogonal to the direction in which the assumed tsunami flow proceeds. In addition, when the state where the side lower frame 15 is installed at a predetermined position of the initial rubble mound is viewed from above, the side lower frame 15 is closed in a horizontal plane and is set on the initial rubble mound. In this state, the water flow permeable bottom member 26 is located at the bottom.

  After the installation of the lower side frame 15 on the initial rubble mound is completed, the inner packing stone 16 is filled inside the lower side frame 15 and further rubble and covering stones are installed on the initial rubble mound. The lower frame 15 is rooted in the rubble mound 12.

  When filling the inner packing stone 16 inside the lateral lower frame 15, for example, as shown in FIG. 8, filling the inner packing stone 16 from above into the inner side of the lateral lower frame 15 using a shooter 90. Can do. Since the side lower frame 15 has already been installed on the initial rubble mound, it is not necessary to block the medium packing stone 16 in advance with a snake basket or the like.

  After the filling of the filling stone 16 inside the lateral lower frame 15 is completed, the water permeable cover member 24 is attached to the water permeable planar member 20 and the wall body 22 by underwater work, and the filled filling stone 16 is filled. The upper part is covered with a water flow permeable lid member 24 to complete the steel frame 14 and the submerged dam 10 is completed.

  In the construction procedure described above, the side lower frame 15 including the water flow permeable planar member 20, the wall body 22, and the water flow permeable bottom member 26 is used, and the completed submerged dike 10 (steel frame 14) is Although the water-permeable bottom member 26 is also included, if it is confirmed that the stability (safety) of the dike can be ensured as a result of the verification, the water-permeable bottom member 26 may be omitted. When the water flow permeable bottom member 26 is omitted, the side lower frame 15 is used by using a steel frame (hereinafter referred to as a side frame) composed of the water flow permeable planar member 20 and the wall body 22. What is necessary is just to perform the construction similar to the case.

  In addition, when the state where the side frame is installed at a predetermined position of the initial rubble mound is viewed from above, the side frame is closed in a horizontal plane, but unlike the side lower frame 15, There is no water flow permeable bottom member 26.

DESCRIPTION OF SYMBOLS 10 ... Submerged dike 12 ... Rubble mound 14 ... Steel frame 15 ... Side lower frame 16 ... Medium clogging stone 18 ... Main-body structural part 20 ... Water flow permeability planar member 22, 32, 34 ... Wall body 24 ... Water flow permeability Lid member 26 ... Water-permeable bottom member 28 ... Space 50, 76 ... Steel pipe 52, 70, 72, 78, 79 ... Shape steel 54, 74, 80 ... Round steel 60, 82 ... Side steel pipe 62, 84 ... Vertical steel pipe 64, 86 ... Horizontal steel pipe 66, 88 ... Brace steel pipe 68 ... Curved steel pipe 90 ... Shooter

Claims (5)

  A method of constructing a submerged dike by constructing a submerged dike by installing a frame on the rubble mound so that at least a part is embedded in the rubbing mound,
  And having a plurality of water permeable planar members facing each other, and having a plurality of walls substantially orthogonal to the horizontal direction in which the water permeable planar members extend in a state of being installed on the rubble mound, It has a shape closed in a horizontal plane when viewed from above in the state installed on the rubble mound, and further has a water permeable bottom member at the bottom in the state installed on the rubble mound, and After the upper side is opened on the rubble mound so that the horizontal direction in which the water flow permeable planar member extends is substantially perpendicular to the direction in which the assumed tsunami flow proceeds,
  The inside packing stone is inserted from above so as not to pass through the water flow permeable planar member inside the side lower frame, and further rubble is laid on the rubble mound, and the inserted stuffing stone and Cover the lower perimeter of the side lower frame with the laid rubble, and root,
  Furthermore, the construction method of a submerged dike characterized by covering the upper part of the lateral lower frame with a water-permeable cover member so that the inserted cobblestone does not come out from the upper part of the lateral lower frame.   Of the filling stones that are put into the inside of the lateral lower frame, the filling stones that are thrown into the portion in contact with the water flow permeable planar member are sized not to pass through the water flow permeable planar member, The method for constructing a submerged dike according to claim 1, wherein the medium clogging stone introduced into a portion in contact with the water flow permeable lid member is of a size that does not pass through the water flow permeable lid member.   A method of constructing a submerged dike by constructing a submerged dike by installing a frame on the rubble mound so that at least a part is embedded in the rubbing mound,
  And having a plurality of water permeable planar members facing each other, and having a plurality of walls substantially orthogonal to the horizontal direction in which the water permeable planar members extend in a state of being installed on the rubble mound, When viewed from above in the state installed on the rubble mound, it has a closed shape in a horizontal plane, and in the state installed on the rubble mound, the upper side is opened to the side frame, After installing on the rubble mound so that the horizontal direction in which the textured surface member extends is substantially orthogonal to the direction in which the assumed tsunami flow proceeds,
  Inside the side frame is filled with a filling stone from above so as not to pass through the water flow permeable planar member, and also laid a rubble on the rubble mound, and the filled filling stone and laying Cover the lower part of the side frame with the rubble,
  Furthermore, the construction method of the submerged dike characterized by covering the upper part of the side frame with a water flow permeable lid member so that the inserted clogging stone does not come out from the upper part of the side frame.   Of the filling stones that are put inside the side frame, the filling stones that are put into a portion that contacts the water flow permeable planar member are sized not to pass through the water flow permeable planar member, 4. The method of constructing a submerged levee according to claim 3, wherein the clogging stone put into a portion in contact with the permeable lid member is sized so as not to pass through the water flow permeable lid member.   The method for constructing a submerged levee according to any one of claims 1 to 4, wherein the medium packing stone is introduced by a shooter.

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