Metropolitan disaster prevention facility

Abstract

To provide a metropolitan disaster prevention facility.SOLUTION: An urban disaster prevention facility comprises a tsunami-resistant ceiling river dike installed in a sea near a coastline and makes river water from both ends of a ceiling river along a coastline into the open sea. The urban disaster prevention facility comprises a ceiling river dike 5 not requiring land reclamation and is provided in a sea on a comparatively shallow seabed continuously from neighboring riverbanks of a plurality of neighboring rivers, and a tsunami countermeasure dike 7 that is provided on an open sea side of the ceiling river levee 5 not requiring land reclamation and has a plurality of openings 7a whose both ends connect to the coastline.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The object of the present invention is to provide disaster prevention facilities for large cities by installing tsunami-resistant ceiling river levees near the coastline or in the sea on a relatively shallow seabed. [Background technology]

[0002] At the end of the last ice age, Tokyo Bay, Ise Bay, and Osaka Bay were submerged one after another due to a 100-meter rise in sea level, resulting in the current coastline of the Japanese archipelago. This invention is a related application to the earlier application for a flood prevention levee or tsunami prevention levee (Patent Application No. 2022-162288). The applicant has also filed an application for a tsunami countermeasure floating device (Patent Application No. 2020-76287). Although not an invention of the present applicant, Hitachi Zosen Corporation has registered patents for floating flap gates, including Patent No. 5329452 and 33 others. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5329452 [Patent Document 2] Patent No. 5476209 [Patent Document 3] Patent No. 5529001 [Patent Document 4] Patent No. 5762882 [Patent Document 5] Patent No. 5718732 [Patent Document 6] Patent No. 5580785 [Patent Document 7] Patent No. 5631818 [Patent Document 8] Patent No. 5845025 [Patent Document 9] Patent Publication No. 5845051 [Patent Document 10] Patent No. 5718792 [Patent Document 11] Patent No. 5971956 [Patent Document 12] Patent No. 5873743 [Patent Document 13] Patent No. 5873759 [Patent Document 14] Patent No. 5883756 [Patent Document 15] Patent No. 5948206 [Patent Document 16] Patent No. 6158503 [Patent Document 17] Patent No. 6117280 [Patent Document 18] Patent No. 6235403 [Patent Document 19] Patent No. 6262608 [Patent Document 20] Patent No. 6438282 [Patent Document 21] Patent No. 6435455 [Patent Document 22] Patent No. 6382094 [Patent Document 23] Patent No. 6431401 [Patent Document 24] Patent No. 6480221 [Patent Document 25] Patent No. 6461699 [Patent Document 26] Patent No. 6652409 [Patent Document 27] Patent No. 6696681 [Patent Document 28] Patent No. 6438555 [Patent Document 29] Patent No. 6626180 [Patent Document 30] Patent No. 6856487 [Patent Document 31] Patent No. 7145102 [Patent Document 32] Patent No. 7203710 Summary of the Invention [Problem to be solved by the invention]

[0004] The first object of the present invention is to provide disaster prevention facilities for large cities by installing tsunami-resistant ceiling river levees 7 with multiple openings 7a in the sea along the coastlines of large cities in Japan, such as Tokyo Bay, Ise Bay, and Osaka Bay. The second objective of this invention is to provide land along the coastlines of Japan, such as Tokyo Bay, Ise Bay, and Osaka Bay, that does not require reclamation. [Means for solving the problem]

[0005] The present invention aims to provide disaster prevention facilities for large cities by providing a tsunami-resistant ceiling river levee 7 with multiple openings 7a provided underwater near the coastline or in a relatively shallow seabed, and by allowing river water to flow into the open sea through the multiple openings 7a. The metropolitan disaster prevention equipment according to claim 1 comprises: A tsunami-resistant ceiling river levee equipped in the sea near the coastline and with multiple openings that connect both ends to the coastline. The system is characterized in that flap gate-type seawalls or floodgates are provided at the multiple openings, allowing river water to flow from the multiple openings into the open sea. The metropolitan disaster prevention device according to claim 2 is The system is characterized by comprising: an overhead river levee that does not require landfilling and is continuous with both adjacent riverbanks of multiple rivers and extends to the relatively shallow seabed; a tsunami-resistant overhead river levee that is connected to the coastline on the open sea side of the overhead river levee that does not require landfilling and has multiple openings; and flap-gate type seawalls or floodgates that are provided at the multiple openings, allowing river water to flow into the open sea from the multiple openings. The metropolitan disaster prevention equipment according to claim 3 comprises: An overhead river levee that has an opening at one end in the sea near the coastline and the other end connected to the coastline. a tsunami-resistant ceiling river levee that does not require landfilling and is provided in the open sea of the ceiling river levee, with one end connected to the opening of the ceiling river levee and the other end connected to the coastline, and a tsunami-resistant ceiling river levee that is provided in the open sea of the ceiling river levee that does not require landfilling and has a plurality of openings that are connected to the coastline at both ends; The method is characterized in that flap gate-type seawalls or water are provided at the multiple openings, and the area between the landfill-free ceiling river levee and the tsunami-resistant ceiling river levee is made into a brackish water area, and river water is allowed to flow into the open sea from the openings of the tsunami-resistant ceiling river levee. The metropolitan disaster prevention equipment according to claim 4 is The invention is characterized by comprising an overhead river levee with openings at both ends that is provided in the sea near the coastline, an overhead river levee that does not require landfill that is provided from both ends of the overhead river levee to relatively shallow waters, a tsunami-resistant levee 7 that is provided in the open sea from the overhead river levee that does not require landfill and has multiple openings 7a that connect both ends to the coastline, and flap-gate type seawalls or sluice gates that are provided at the multiple front openings, making the area between the overhead river levee that does not require landfill and the tsunami-resistant overhead river levee a brackish water area and allowing river water to flow into the open sea from the openings in the tsunami-resistant accompanying river levee. The metropolitan disaster prevention equipment according to claim 5 comprises: The system is characterized by comprising two coastlines of the strait, two coastline ceiling river levees provided in the sea near the two coastlines and having openings at both ends, two ceiling river levees not requiring landfill provided in the relatively shallow sea at both ends of the ceiling river levees, and a tsunami-resistant levee with openings provided parallel to the outside of the two ceiling river levees not requiring landfill, with a canal between the tsunami-resistant ceiling river levees 7 and a brackish water area between the levees not requiring landfill and the tsunami-resistant levees, and river water flowing from the openings into the open sea. The metropolitan disaster prevention facility described in claim 6 includes a first reclamation-free ceiling river levee that is continuous with both adjacent riverbanks of a plurality of rivers and extends to the seabed of a relatively shallow sea, and The tsunami-resistant ceiling river levee comprises an overhead river levee with openings at both ends that is provided in the sea near the coastline, a second ceiling river levee that does not require landfill that is provided parallel to the side of the first ceiling river levee from both ends of the ceiling river levee to relatively shallow waters, both ends of which connect to the coastline and have a plurality of openings that are provided parallel to both of the ceiling river levee that do not require landfill, and flap-gate type seawalls or floodgates that are provided at the plurality of openings, allowing river water to flow into the open sea from the plurality of openings. [Effects of the Invention]

[0006] According to the present invention, disaster prevention measures for large cities are possible by discharging river water or brackish water into the open sea from the multiple openings 7a of a tsunami-resistant levee 7, which has multiple openings 7a connected to both ends of the coastline and is provided near the coastline or in the seabed at a relatively shallow depth. Furthermore, there is provided an overhead river levee 5 that does not require landfilling, which is provided from the adjacent riverbank of an adjacent river to the relatively shallow seabed, and a tsunami-resistant levee 7 that has multiple openings 7a on both ends that run parallel to the open sea of the above-mentioned overhead river levee 5 that does not require landfilling, and the above-mentioned overhead river levee 6 that does not require landfilling makes it possible to create land that does not require landfilling, and the area between the above-mentioned overhead river levee 5 that does not require landfilling and the above-mentioned tsunami-resistant levee 7 becomes a brackish water area, and river water can be discharged from the multiple openings of the tsunami-resistant levee 7 into the open sea, making disaster prevention in large cities possible. [Brief explanation of the drawings]

[0007] [Figure 1] This shows the current coastline of the Japanese archipelago and the coastline during the ice age. [Figure 2] An example of a tsunami prevention dike 7 that is provided near the coastline or in the sea on a relatively shallow seabed and has multiple openings 7a is shown. [Figure 3a] A current map of Osaka Bay is shown. [Figure 3b] A current map of Tokyo Bay is shown. [Figure 3c] A current map of Mikawa Bay is shown. [Figure 3d] Shows the current landfill in Tokyo. [Figure 3e] Shows the current landfill in Yokohama. [Figure 3f] Shows the current landfill in Nagoya. [Figure 4] A map showing the area from Kyushu to Tokyo Bay. [Figure 5] 1 shows a dike wall in which the dike wall and dike reinforcement members are fixed by dike fixing vertical columns. [Figure 6] An example of a tsunami-resistant ceiling river levee 7 having a plurality of openings 7a provided in the sea is shown. DETAILED DESCRIPTION OF THE INVENTION

[0008] Figure 1 shows the current coastline of the Japanese archipelago and the coastline during the Ice Age. At the end of the last ice age, Tokyo Bay, Ise Bay, and Osaka Bay were submerged one after another due to a 100-meter rise in sea level, resulting in the current coastline of the Japanese archipelago. FIG. 2 shows a concrete example of a tsunami prevention dike 7 provided near the coastline or in the sea on a relatively shallow seabed and having a plurality of openings 7a. FIG. 2a shows an embodiment of a tsunami-resistant covered river levee 7 provided in the sea near the coastline and having a plurality of openings 7a. The figure shows a coastline 1, a plurality of rivers 2, and an embodiment of a tsunami-resistant covered river levee 7 having a plurality of openings 7a. The openings 7 a are equipped with known flap gate-type seawalls 8 or floodgates 9 to prevent tsunamis from reaching the coastline 1 . Fig. 2b shows an embodiment in which an overhead river levee 4 with an opening at one end is blocked off at the other end by a landfill-free overhead river levee 5, and a tsunami-resistant levee 7 with multiple openings 7a in the open sea of the landfill-free overhead river levee 5. Fig. 2c shows an embodiment in which an overhead river levee 4 with openings at both ends is provided near the coastline, and an overhead river levee 5 with no landfill required is provided in the sea from both ends of the opening in a relatively shallow seabed, and a tsunami-resistant overhead river levee 7 is provided in the open sea of the above-mentioned landfill-free overhead river levee 5. Fig. 2d shows an embodiment in which an overhead river levee 5 with no landfill required is provided in the sea in a relatively shallow seabed, continuing from the adjacent banks of multiple adjacent rivers, and a tsunami-resistant levee 7 with multiple openings 7a in the open sea side of the above-mentioned landfill-free overhead river levee 5, both ends of which connect to the coastline. Figure 2e shows an example of urban disaster prevention equipment on a single coastline, which has an overhead river levee 4 in the sea near the coastline, with openings b at both ends of the overhead river levee 3, and a series of overhead river levee 3 with openings 4b3b.

[0009] Fig. 3a shows a current map of Osaka Bay, Fig. 3b shows Tokyo Bay, and Fig. 3c shows Mikawa Bay. Specific examples of an enclosed river levee 4 with openings at both ends provided near the coastline of Fig. 2c, an enclosed river levee 5 provided underwater on a relatively shallow seabed from both ends of the openings and not requiring landfill, and an enclosed river levee 7 for tsunami prevention provided in the open sea from the enclosed river levee 5 not requiring landfill are being implemented. Fig. 3b This example shows an example in which an overhead river levee 4 is located near the coastline connecting the coastline sides of Kobe, Osaka, Kobe Airport, and Kansai Airport in Osaka Bay, an overhead river levee 5 that does not require landfilling and extends to relatively shallow waters that connect to the open sea side of the airport, and a tsunami-resistant levee 7 that has multiple openings 7a in the open sea of the overhead river levee 5 that does not require landfilling. In Mikawa Bay, disaster prevention for large cities is possible with an embodiment that includes an overhead river levee 4 that connects the coastline side of Chubu Centrair International Airport and extends near the coastline up to Matsusaka, an overhead river levee 5 that does not require landfill and extends into relatively shallow waters connecting the coastline near Chubu Centrair International Airport with the coastline near Matsusaka, and a tsunami-resistant levee 7 that has multiple openings 7a in the open sea of the overhead river levee 5 that does not require landfill.In Tokyo Bay, an embodiment is shown that includes an overhead river levee 4 that extends near the coastline from Urayasu to Yokosuka, an overhead river levee 5 that does not require landfill and extends from both ends of the overhead river levee 4 between Kisarazu and Yokosuka to relatively shallow waters, and a tsunami-resistant levee 7 that connects the coastlines of Kisarazu and Yokosuka and has multiple openings 7a in the open sea of the overhead river levee 5 that does not require landfill. Figure 2c shows an example of an overhead river levee 4 with openings at both ends near the coastline, an overhead river levee 5 that does not require landfill and is installed in the sea on a relatively shallow seabed from both ends of the openings, and an overhead river levee 7 that is tsunami-resistant and is installed in the open sea beyond the overhead river levee 5 that does not require landfill, making it possible to prevent disasters in large cities. Figure 4 shows the current state of a large city with reclaimed land, and an example of a tsunami-resistant levee 7 is specifically implemented, which is provided in the sea on a relatively shallow seabed and continues from the adjacent riverbanks of a plurality of adjacent rivers shown in Figure 2d, and which has a plurality of openings 7a on the open sea side of the above-mentioned levee 5 that does not require reclamation and which connects both ends to the coastline. The embodiment also includes a coastline 1 and a river 2 that drain the river water of adjacent rivers into the open sea, the coastline 1 and the river 2 being characterized by comprising an overhead river levee 5 that does not require landfilling and that extends continuously from adjacent riverbanks of a plurality of adjacent rivers to the underwater area of a relatively shallow seabed, an overhead river levee that is provided on the open sea side of the overhead river levee that does not require landfilling and has a plurality of openings 7a, and a flap-gate type seawall or sluice gate provided at the plurality of openings, and allowing the river water to flow into the open sea from the plurality of openings. In the reclaimed land in Tokyo, Yokohama, and Chiba shown in Figure 4, for example, if a first ceiling river levee 5 that does not require landfilling is installed continuously from the adjacent riverbanks of the Arakawa River and the Sumida River in Tokyo or the nearby coastline to the relatively shallow seabed, an ceiling river levee 4 near the coastline from the opposite bank of the Sumida River to the eastern bank of the Tsurumi River, a second ceiling river levee 4b that does not require landfilling is installed connected to the openings at both ends of the ceiling river levee 4 and parallel to the side of the first ceiling river levee 4a that does not require landfilling, and a tsunami-resistant ceiling river levee 7 that is installed parallel to the open sea of both ceiling river levee 5a and 5b that do not require landfilling are installed, connecting both ends to the coastline, it will be possible to realize land 6 that does not require landfilling from Tokyo to Yokohama. In Yokohama, if an overhead river levee (5) that does not require landfilling is constructed along the adjacent riverbanks or nearby coastlines of the Tama River and the Tsurumi River, extending from the adjacent riverbanks to the relatively shallow underwater seabed, it would be possible to create land that does not require landfilling (6) outside of reclaimed land. Furthermore, if an overhead river levee (5) that does not require landfilling is constructed connecting the western bank of the Tsurumi River or the nearby coastline with the coastline near Yokosuka, extending to the relatively shallow underwater seabed, it would also be possible to create land that does not require landfilling (6) outside of reclaimed land. The rivers in Osaka Bay are complex, but similar construction is possible. In Akashi, an overhead river levee (5) that does not require landfilling connects the east side of the Kakogawa River from the eastern shore to the coastline at Akashi's eastern end to the relatively shallow underwater seabed, and a tsunami-resistant levee (7) with multiple openings (7a) to the open sea from the overhead river levee (5) would enable disaster prevention and land that does not require landfilling in Akashi.

[0010] One example of urban disaster prevention facilities along a single coastline such as Tokyo Bay, Osaka Bay, Ise Bay, and the Tohoku coast can be specifically implemented as the example shown in Figure 2e, and is characterized by comprising an overhead river levee 5 that does not require landfilling and that extends continuously from the adjacent riverbanks of a plurality of adjacent rivers to the relatively shallow seabed, a tsunami-resistant overhead river levee 7 that is provided on the open sea side of the overhead river levee that does not require landfilling and has a plurality of openings 7a, and flap-gate type seawalls 8 or sluice gates 9 that are provided at the plurality of openings 7a, and which allows river water from adjacent rivers to flow into the open sea from the plurality of openings 7a. In this embodiment, the applicant's tsunami countermeasure floating device (JP Patent Publication No. 2020-76287) is implemented as a tsunami countermeasure offshore to weaken tsunamis, and the guiding float member is used for offshore wind power generation. As a final tsunami countermeasure, a known floating flap gate 8 or sluice gate 9 is used in the opening 7a.

[0011] Figure 5 shows a perspective view of a levee wall 12 having a vertical wall portion 12b at the other end of a horizontal connecting rod or horizontal connecting plate 12a which has vertical pipes 12c that penetrate the levee wall 12 and fit together, Figure 5a or Figure 5b shows a perspective view of a levee wall 12 having a vertical wall portion 12b at the other end of a horizontal connecting rod 12a which has vertical pipes 12c that penetrate a thick levee-fixing vertical square pillar or two levee-fixing vertical cylinders 11 and fit together, and Figure 5b shows a perspective view of a levee wall 12 having a vertical wall portion 12b at the other end of a vertical connecting plate 12a which has two vertical pipes 12c that penetrate two thick levee-fixing vertical cylinders 11 and fit together. Figure 5c shows an L-shaped embankment wall reinforcing member 13 having a vertical tube 13c that penetrates and fits between a thick embankment-fixing vertical square column or two embankment-fixing vertical circular columns 11 and is provided with a reinforcing portion 13b; Figure 5d shows a U-shaped embankment wall reinforcing member 13 having a vertical tube 13c that penetrates and fits between a thick embankment-fixing vertical square column 11 and is provided with a reinforcing portion 13b; Figure 5e shows an H-shaped embankment wall reinforcing member 13 having a vertical tube 13c that penetrates and fits between a thick embankment-fixing vertical square column 11 and is provided with a reinforcing portion 13b; Figure 5f shows a U-shaped embankment wall reinforcing member 13 having a vertical tube 13c that penetrates and fits between two embankment-fixing vertical circular columns 11 and is provided with a reinforcing portion 13b; and Figure 5g shows a plate-shaped embankment wall reinforcing member having a vertical tube 13c that penetrates and fits between two embankment-fixing vertical circular columns 11 and is provided with a reinforcing portion 13b. FIG. 5b shows a perspective view of the embankment wall 12, which has a vertical wall portion 12b at the other end of a vertical connecting plate 12a having two vertical pipes 12c that penetrate and fit into two thick vertical cylinders 11 fixed to the embankment. Figure 5c shows an L-shaped embankment wall reinforcing member 13 having a vertical tube 13c that penetrates and fits between a thick embankment-fixing vertical square column or two embankment-fixing vertical circular columns 11 and is provided with a reinforcing portion 13b; Figure 5d shows a U-shaped embankment wall reinforcing member 13 having a vertical tube 13c that penetrates and fits between a thick embankment-fixing vertical square column 11 and is provided with a reinforcing portion 13b; Figure 5e shows an H-shaped embankment wall reinforcing member 13 having a vertical tube 13c that penetrates and fits between a thick embankment-fixing vertical square column 11 and is provided with a reinforcing portion 13b; Figure 5f shows a U-shaped embankment wall reinforcing member 13 having a vertical tube 13c that penetrates and fits between two embankment-fixing vertical circular columns 11 and is provided with a reinforcing portion 13b; and Figure 5g shows a plate-shaped embankment wall reinforcing member having a vertical tube 13c that penetrates and fits between two embankment-fixing vertical circular columns 11 and is provided with a reinforcing portion 13b.Figure 5a shows a thick embankment fixed vertical square, and Figure 5b shows a perspective view of an embankment wall 12 having a vertical wall portion 12b at the other end of a horizontal connecting rod or horizontal connecting plate 12a which has two vertical pipes 12c that penetrate two thick embankment fixed vertical cylinders 11 and fit together. Fig. 5c is a perspective view of an L-shaped embankment wall reinforcing member 13 having a vertical tube 13c that penetrates and fits into a thick vertical square pillar 11 for fixing the embankment or two vertical circular pillars 11 for fixing the embankment and having a reinforcing portion 13b. Figs. 5c to 5f are perspective views of a U-shaped or V-shaped embankment wall reinforcing member 13. Fig. 5g is a perspective view of a plate-shaped embankment wall reinforcing member 13. Fig. 13, Fig. 5e shows an H-shaped embankment wall reinforcing member 13 having a vertical tube 13c that penetrates and fits into a thick embankment-fixing vertical square column 11 and is equipped with a reinforcing portion 13b, Fig. 5f shows a U-shaped embankment wall reinforcing member 13 having a vertical tube 13c that penetrates and fits into two embankment-fixing vertical cylinders 11 and is equipped with a reinforcing portion 13b, and Fig. 5g shows a plate-shaped embankment wall reinforcing member having a vertical tube 13c that penetrates and fits into two embankment-fixing vertical cylinders 11 and is equipped with a reinforcing portion 13b. 5c to 5c show an L-shaped embankment wall reinforcing member 13 having a vertical tube 13c that penetrates and fits into a thick embankment fixed vertical square column or two embankment fixed vertical circular columns 11 and having a reinforcing portion 13b, FIG. 5d shows a U-shaped embankment wall reinforcing member 13 having a vertical tube 13c that penetrates and fits into a thick embankment fixed vertical square column 11 and having a reinforcing portion 13b, and FIG. 5e shows a thick embankment fixed vertical square column 11. Figure 5f shows an H-shaped embankment wall reinforcing member 13 having vertical tubes 13c that penetrate and fit together and having reinforcing portions 13b, Figure 5f shows a U-shaped embankment wall reinforcing member 13 having vertical tubes 13c that penetrate and fit together between two embankment fixed vertical cylinders 11 and having reinforcing portions 13b, and Figure 5g shows a plate-shaped embankment wall reinforcing member having vertical tubes 13c that penetrate and fit together between two embankment fixed vertical cylinders 11 and having reinforcing portions 13b.

[0012] Figure 6 shows an overhead river levee 4 that is fixed in a plane by two thick vertical circular or square pillars 11 for fixing the levee and is provided near the coastline or in the seabed at a relatively shallow depth, and an overhead river levee 7 that does not require landfill and is provided at both ends of the overhead river levee 4 in the seabed at a relatively shallow depth, or an overhead river levee 7 that is connected to the coastline and is provided in the seabed at a relatively shallow depth. Figure 6a shows a dike wall 12 having two thick vertical columns 11 fixed to the dike with earthquake-resistant devices, a lower horizontal connecting plate 12a having a vertical pipe 12c at one end that penetrates and fits into the thick vertical columns 11 fixed to the dike, and a vertical wall portion 12c at the other end, and L-shaped dike wall reinforcing members 13 having vertical pipes 13c that penetrate and fit into the two thick vertical columns 11 fixed to the dike, and having reinforcing portions 13b that reinforce the dike wall 12c, above and below the horizontal connecting plate 12a of the dike wall 12. On top of the upper L-shaped dike wall reinforcing member, there is provided a bottom-mounted offshore wind power generation member 16 having a vertical pipe 16 at one end that penetrates the thick vertical columns fixed to the dike. The height of the levee wall 12 varies depending on whether it is a reclamation-free levee 5, a tsunami-resistant covered river levee 7, or a tsunami-resistant levee 7. In the case of a reclamation-free levee 5 installed in relatively shallow seas, it will be at the same height above sea level as a covered river levee 4. Figure 6b shows two thick vertical columns 11 fixed to the embankment with earthquake-resistant devices, an embankment wall 12 having a bottom horizontal connecting plate 12 at one end with a vertical pipe 12c that penetrates and fits into the thick vertical columns 11 fixed to the embankment at the other end, an H-shaped embankment wall reinforcing member 13 having a vertical pipe 13c that penetrates and fits into the two thick vertical columns 11 fixed to the embankment at the bottom horizontal connecting plate 12a of the embankment wall 12 and having a reinforcing portion 13b that reinforces the embankment wall 12c, and a plate-shaped embankment wall reinforcing member 13 placed on top of the H-shaped embankment wall reinforcing member 13. A bottom-mounted offshore wind power generation member 16 equipped with a vertical pipe 16 is provided on top of the plate-shaped embankment wall reinforcing member 13. Figure 10c shows the state in which the embankment wall 12, which is fixed in a plane to two thick vertical cylinders 11 for fixing the embankment, is connected along the coastline by connecting members 14, and bottom-mounted offshore wind power generation becomes possible by the rotor blades 16a of the bottom-mounted offshore wind power generation member 16. In addition, openings are also made in parts of the connecting members 14 to allow river water to flow into the open sea. The space between the H-shaped embankment wall reinforcement members 13 is equipped with marine freight railways in different directions, making it possible to transport cargo using the ceiling river levees 4 or tsunami-resistant ceiling river levees 7 installed near the coastlines of the Japanese archipelago, and it is also possible to install an over-sea walkway on top of the plate-shaped embankment wall reinforcement members 13. [Explanation of symbols]

[0013] 1. Coastline 2. Rivers 3 river bank 4. Ceiling River Levee 5. Ceiling river levees that do not require landfilling 6. Land that does not require reclamation 7. Tsunami-proof ceiling river levees 7a aperture 11 Thick embankment fixing pillar 12 Embankment Wall 13 Embankment wall reinforcement members 14 Joint Agent 16 Bottom-mounted wind power generation components

Claims

1. a tsunami-resistant ceiling river levee provided in the sea near the coastline and having a plurality of openings whose both ends connect to the coastline; A flap gate type seawall or a floodgate is provided at the plurality of openings, A disaster prevention facility for large cities, characterized in that river water is discharged into the open sea from multiple of the openings.

2. An overhead river levee that does not require landfilling and is continuous with both adjacent riverbanks of multiple rivers and extends to the relatively shallow seabed. a tsunami-resistant ceiling river levee provided on the open sea side of the landfill-free ceiling river levee, connected to the coastline and having a plurality of openings; A flap gate-type seawall or a floodgate is provided at the plurality of openings, A disaster prevention facility for large cities, characterized in that river water is discharged into the open sea from multiple of the openings.

3. an overhead river levee that is provided in the sea near the coastline and has an opening at one end and the other end connected to the coastline; an overhead river levee that does not require landfilling and is connected to the opening at one end of the overhead river levee and has the other end connected to the coastline and extends to a relatively shallow sea; a tsunami-resistant ceiling river levee provided on the open sea of the landfill-free ceiling river levee and having a plurality of openings whose both ends are connected to the coastline; A flap gate-type seawall or a floodgate is provided at the plurality of openings, A disaster prevention device for large cities, characterized in that the area between the landfill-free ceiling river levee and the tsunami-resistant levee is a brackish water area, and river water is discharged into the open sea from the opening of the tsunami-resistant ceiling river levee.

4. The two coastlines of the strait, two coastline elevated river levees provided in the sea near the two coastlines and having openings at both ends; two ceiling river levees that do not require landfilling and are provided in relatively shallow waters at both ends of the ceiling river levees; A tsunami-prevention levee having an opening provided parallel to the outside of the two landfill-free ceiling river levee is provided, A large-scale disaster prevention system for large cities, characterized in that the space between the tsunami-resistant ceiling river levees 7 is made into a canal, the space between the landfill-free levee and the tsunami-resistant levee is made into a brackish water area, and river water is discharged into the open sea from the opening.

5. The two coastlines of the strait, an elevated river levee provided in the sea near the two coastlines and having openings at both ends; an overhead river levee that does not require landfilling and is provided in relatively shallow waters at both ends of the overhead river levee; An urban disaster prevention device comprising a tsunami-resistant levee having an opening provided parallel to the outside of the landfill-free ceiling river levee, and a brackish water area is formed between the landfill-free levee and the tsunami-resistant levee, and river water is allowed to flow from the opening into the open sea.

6. A first ceiling river levee that does not require landfilling and is continuous with both adjacent riverbanks of multiple rivers and extends to the relatively shallow seabed. an overhead river levee with openings at both ends provided in the sea near the coastline of both adjacent river banks; a second overhead river levee that does not require reclamation and is provided parallel to the side of the first overhead river levee from both ends of the overhead river levee to a relatively shallow depth in the sea; and a tsunami-resistant overhead river levee with a plurality of openings provided parallel to both of the overhead river levee that do not require reclamation and whose both ends are connected to the coastline; A disaster prevention facility for large cities, characterized in that flap gate-type seawalls or water gates are provided at the plurality of openings, and river water is allowed to flow from the plurality of openings into the open sea.

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