JP6217881B1 - Harbor bottom structure and harbor bottom burying prevention method - Google Patents

Abstract

The purpose of the present invention is to provide a harbor bottom structure and a harbor bottom burying prevention method capable of suppressing a change in water depth due to sedimentation of a predetermined water area by sediments and extending a maintenance dredging construction interval. . A groove-like sediment trapping part 122, in which sediment is trapped deeper than the bottom of the water inside the anchorage 12, along the boundary BL with the navigation channel 14, which is an adjacent water area, is continuously provided at the periphery of the anchorage 12 that is a predetermined water area. Provided. Since sediments such as sand and floating mud that flowed in from the channel 14 are captured by the sediment capturing unit 122 and do not flow into the anchorage 12, the water depth of the anchorage 12 is prevented from changing, and maintenance dredging work is performed. The interval can be increased.

Description

  The present invention relates to a water bottom structure and a water bottom burying prevention method for preventing the bottom of a harbor from being buried by sediment.

  In harbors, sand and floating mud flowing from rivers accumulate on the seabed (water bottom), and the sediment raises the seabed and shallows the water. In order to secure the necessary water depth for navigating and berthing in this port, conventional depth surveys have been carried out regularly in the port so that the water area where the necessary water depth cannot be ensured is kept at the prescribed depth. Maintenance dredging works to be carried out regularly. In this maintenance dredging work, for example, dredging to obtain a uniform reference water depth and extra excavation are performed in accordance with the technical level of each port.

  The interval between maintenance dredging works depends on the sediment deposition rate at each port. For example, in a water area that contains a large amount of organic matter and a large amount of floating mud is generated, the frequency and amount of maintenance dredging work increases. In addition, in dredged water areas, the frequency of maintenance dredging works may increase due to collapse near the slope. The maintenance dredging work costs a lot of money, and the use of the port is restricted during the construction, and the available water area becomes narrow, so the operational efficiency and safety are reduced. For this reason, it has been desired to extend the interval between maintenance dredging works.

  For example, in the route burying prevention method described in Patent Document 1, a trench is provided in a plurality of locations at the bottom of the channel at appropriate intervals along the axis of the channel. In addition, in this method for preventing burial of the channel, it has also been proposed to provide a digging outside the channel. According to this, since the floating mud soared by the waves can be dug and accumulated, it is possible to lengthen the construction interval of the maintenance dredging work.

  By the way, there are multiple water areas such as routes and anchorage in the port. There may not be. For example, in a port used for carrying fuel in a thermal power plant, the anchorage is managed by the power company, and the public route is managed by the national and local governments. As a result, the power company can perform dredging work at the anchorage, but it cannot perform dredging work on the channel.

Japanese Patent No. 4041903

  Changes in the depth of water in the harbor are caused not only by the accumulation of sand and floating mud flowing from the river, but also by the movement of sediment between adjacent water bodies. For example, when floating mud soars due to ship navigation or waves, the soaring mud may flow into the adjacent water area. In addition, when the height of the sea bottom is different between adjacent water areas, the slope generated at the boundary may collapse and the sediment may flow into the adjacent water areas. In such a situation, when adjacent water areas are managed by the same manager, it is possible to reduce sediment movement between the water areas by regularly performing maintenance dredging work in both water areas. However, when the managers of the adjacent water areas are different, dredging work cannot be carried out on the adjacent water areas, so conventionally it was impossible to prevent the sediment from flowing out from the adjacent water areas.

  According to the route embedding prevention method of Patent Document 1, since the digging is provided in the channel managed by itself, it can be applied even if the manager of the adjacent water area is different, but the position and shape of the digging However, it remains unclear whether floating mud flowing from the adjacent water area or sand collapsed from the adjacent water area can be accumulated. Moreover, although the example which provides a digging in the outer side of a channel is described in patent document 1, when the outer side of the channel is a different water area of a manager, forming a digging arbitrarily. It cannot be applied, so it cannot be applied.

  Accordingly, the present invention provides a harbor bottom structure and a harbor bottom burying prevention method capable of suppressing a change in water depth due to sedimentation of a predetermined water area by deposits and extending a maintenance dredging construction interval. For the purpose.

In order to solve the above-mentioned problem, the invention according to claim 1 is a water bottom structure for preventing anchorage arranged adjacent to a port structure from being buried by sediment, A harbor bottom structure comprising a sediment trapping part that traps sediment deeper than the bottom of the water at a peripheral edge of the bottom of the anchorage so as to surround other than the side that contacts the structure.

According to the present invention, for the anchorage arranged adjacent to the port structure, deposits are formed at the periphery of the bottom of the water in the anchorage rather than the inner bottom of the periphery so as to surround other than the side in contact with the structure . A sediment trapping part is provided in which the bottom of the water is lowered by dripping deeply. In the present invention, the deposit capturing part captures deposits such as sand and floating mud and prevents the deposits from flowing into the predetermined water area.

According to a second aspect of the present invention, in the bottom structure of a harbor according to the first aspect, a plurality of the deposit capturing portions are discretely provided along a side other than the side in contact with the structure of the anchorage. It is characterized by that.

According to a third aspect of the present invention, in the harbor bottom structure according to the second aspect, the number of installations of the deposit capturing unit is adjusted according to the amount of the deposit flowing into the anchorage. Features.

According to a fourth aspect of the present invention, in the bottom structure of a harbor according to any one of the first to third aspects, the depth and width of the sediment trapping portion are determined based on the amount of sediment deposited annually relative to the anchorage. And the volume of the sediment trapping part necessary for maintaining the anchorage at a predetermined water depth based on a maintenance dredging work interval periodically performed to maintain the anchorage at a predetermined water depth. Identifying and determining the volume to be filled .

The invention according to claim 5 is a water bottom burying prevention method for preventing the bottom of the anchorage located adjacent to the port structure from being buried by sediments, except for the side of the anchorage that touches the structure. A sediment trapping part in which sediment is trapped deeper than the bottom of the water is provided at the periphery of the bottom of the water in the anchorage.

The invention described in claim 6 is the harbor submergence prevention method according to claim 5 , wherein a plurality of the deposit capturing parts are provided discretely along a side other than the side in contact with the structure of the anchorage. It is, characterized in that.

The invention according to claim 7 is the method of preventing underwater burial in the harbor according to claim 6, wherein the number of the sediment capturing units is adjusted according to the amount of the sediment flowing into the anchorage. It is characterized by.

The invention according to claim 8 is the method of preventing underwater burial of a harbor according to any one of claims 5 to 7, wherein the depth and width of the deposit capturing part are the same as those of the anchorage. Based on the amount of sediment deposited annually and the maintenance dredging work interval that is regularly performed to maintain the anchorage at a predetermined depth, the deposit necessary to maintain the anchorage at the predetermined depth The volume of the object capturing unit is specified, and the volume is determined so as to be filled.

According to the inventions of claims 1 and 5 , the anchorage placed adjacent to the harbor structure is surrounded by a peripheral edge of the bottom of the water in the anchorage area so as to surround the border of the anchorage. It is provided with the deposit capturing section to lower the water bottom by dredging deep deposits than the bottom of the water, captures deposits such as sand or浮泥that has flowed from the body of water adjacent to the anchorage, deposits of anchorage It becomes possible to prevent it from flowing into the inside and being buried. As a result, the amount of sediment deposited on the inside of the anchorage is reduced, so that the interval between maintenance dredging works is lengthened and the maintenance cost of the port is also reduced. In addition, since there are fewer restrictions on the use of the port during maintenance dredging work, it is possible to suppress a decrease in utilization efficiency and safety.

In addition, since the deposit capturing part is provided so as to surround other than the side in contact with the structure , for example, the construction of the deposit capturing part on the peripheral side of the structure such as the land and the pier can be omitted, It is possible to reduce the construction cost of the capturing part.

Furthermore, sediment trapping part, since the provided so as to surround the other side in contact with the structure, it is possible to capture even if the deposits have flowed from any position of the berth.

According to the invention of claim 2,6, sediment trapping portion. Thus discretely plurality provided along the sides other than the side in contact with the structure of the anchorage, deposits boundary throughout the neighbor waters Since the construction area of the deposit catching part is greatly reduced as compared with the case where the catching part is provided, the construction cost, construction period, etc. can be reduced.

According to the third and seventh aspects of the present invention, a plurality of deposit capturing portions are provided discretely along sides other than the side in contact with the anchorage structure, and the number of installations is set according to the amount of deposits flowing into the anchorage. Since the sediment capture part is provided at regular intervals, it is installed at arbitrary intervals according to the topography of the anchorage, the number of installations is adjusted according to the amount of sediment inflow, etc. The degree of freedom of arrangement is improved.

According to the inventions of claims 4 and 8 , the depth and width of the sediment catching section are determined by the annual amount of sediment deposited on the anchorage and the maintenance dredging work that is periodically performed to maintain the anchorage at a predetermined depth. Based on the construction interval, it is possible to specify the volume of the sediment trapping part necessary for maintaining the anchorage at a predetermined water depth and determine that the volume is satisfied.

According to the invention of claim 8, since placing the deposit capturing unit so as to surround the night place, it is possible to suppress the inflow of deposits from all directions against the anchorage, frequently used as a port facilities berth It becomes possible to lengthen the construction interval of maintenance dredging work.

It is a top view which shows the installation of the harbor which concerns on Embodiment 1 of this invention. It is principal part sectional drawing which shows the water bottom structure of the anchorage of FIG. It is a top view which shows the position of the deposit capture | acquisition part provided in the anchorage of FIG. It is principal part sectional drawing which shows the deposit capture part provided in the anchorage of FIG. It is a graph which shows the annual deposition rate of the deposit in the overnight place of FIG. It is a top view which shows the installation of the harbor which concerns on Embodiment 2 of this invention. It is a top view which shows the installation of the harbor which concerns on Embodiment 3 of this invention.

  The present invention will be described below based on the illustrated embodiments.

(Embodiment 1)
1 to 4 show this embodiment, and FIG. 1 is a plan view showing facilities of the harbor 1 according to this embodiment. The port 1 is, for example, a port for carrying fuel to the thermal power plant 21 built on the land 2 by the ship 31. ) 12, a water intake area (adjacent water area) 13 for taking seawater into the water intake 211 of the thermal power plant 21, a waterway (adjacent water area) 14 through which the ship 31, the ship 32 and the like navigate are provided.

  The pier 11 is connected to the land 2 by a bridge 111 so that an operator of the thermal power plant 21 or a sailor of the ship 31 can move between the pier 11 and the land 2.

  The anchorage 12 is a water area that is set in order for the ship to safely enter and exit from the channel and anchor, and is set in a water area that is in contact with the pier 11, the intake water area 13, and the channel 14. The lodging area 12 is divided into, for example, four areas indicated by reference numerals 12A, 12B, 12C, and 12D, and the four areas as a whole are managed as the accommodation area 12. The anchorage 12 is, for example, a managed water area of an electric power company that operates the thermal power plant 21, and dredging work for removing deposits deposited on the sea floor is performed by the electric power company.

  The channel 14 is a public channel through which a vessel 31 entering and exiting the port 1 or a vessel 32 going to another port navigates, and is a managed water area such as a national or local government. Accordingly, dredging work on the route 14 is performed by the country or local government that is the manager, and the power company that is the manager of the adjacent anchorage 12 cannot perform dredging work on the route 14 without permission.

  FIG. 2 is a cross-sectional view of a principal part showing a state of a part of the seabed of the anchorage 12. In the anchorage 12, sediments 121 such as soil and sand flowing out from a river (not shown) flowing into the harbor 1 and floating mud containing a large amount of organic matter accumulate, so that the sea bottom S rises and the water depth becomes shallow. For this reason, in the anchorage 12, maintenance dredging work for removing the sediment 121 on the seabed periodically (for example, every year) is performed in order to secure a predetermined water depth DW (for example, 7.0 m). This maintenance dredging work is performed, for example, using a heavy machine called grab bucket that can grab the earth and sand. In addition, since the change of the water depth by the sediment 121 also occurs in the intake water area 13 and the channel 14, maintenance dredging work is also periodically performed in these water areas.

  By the way, the change of the water depth in the harbor is generated not only by the accumulation of sand and floating mud flowing out from the river but also by the movement of the deposit 121 between adjacent water areas. For example, in the port 1 of the present embodiment, floating mud that has risen in the channel 14 due to the influence of ship navigation, waves, or the like flows into the anchorage 12 or the seabed slope that occurs at the boundary between the channel 14 and the anchorage 12 It may collapse and earth and sand may flow from the channel 14 to the anchorage 12. As described above, the electric power company that manages the anchorage 12 can perform dredging work on the anchorage 12, but cannot perform dredging work on the channel 14, so conventionally, the deposit 121 from the channel 14. Could not be prevented.

  Therefore, in the present embodiment, as shown in FIG. 3 and FIG. 4 which is a cross-sectional view of the main part of FIG. 3, the sea bottom inside the anchorage 12 is provided at the peripheral edge of the seabed (water bottom) of the anchorage (predetermined water area) 12. A deposit catching part 122 is provided with the deposit 121 deeper than the surface S. Moreover, the deposit capturing part 122 is provided at the peripheral edge on the side of the channel (adjacent water area) 14 adjacent to the anchorage 12, and more specifically, along the boundary BL with the channel 14, that is, along the boundary BL. Provided continuously.

  Furthermore, the sediment catching part 122 is provided in the adjacent water area where the outflow of the sediment 121 is large in the intake water area 13 and the channel 14 (plural adjacent water areas) adjacent to the anchorage 12 or in different adjacent water areas. In this embodiment, it is provided on the side of the route 14 corresponding to both conditions. Moreover, in this Embodiment, in order to maintain the water depth of the anchorage 12 with high use frequency as a port facility for a long period of time, the deposit capturing part 122 is arranged so as to surround the anchorage 12.

  According to the present embodiment, the deposit 121 a that has flowed into the anchorage 12 from the channel 14 can be captured by the deposit capturing unit 122. For example, mud that soars in the channel 14 and flows into the anchorage 12 is captured by the deposit capturing unit 122 before reaching the area inside the anchorage 12. Further, when the slope near the boundary BL collapses and sand flows into the anchorage 12, it is also captured by the deposit capturing part 122 before reaching the area inside the anchorage 12. Therefore, since it is possible to suppress the water depth from being changed by the deposit 121 flowing in from the channel 14, it is possible to make the construction interval of the maintenance dredging work for the anchorage 12 longer than before.

  FIG. 5 is a graph showing the results of measuring the annual deposition rate of the deposit 121 in the anchorage 12 from 1993 (Heisei 5) to 2014 (Heisei 26). In addition, from 2004 (2004) to 2006 (2006), the trapping of sediment with a depth DC from the seabed S inside the anchorage 12 of, for example, 0.5 m and a width W of, for example, 40 m. A portion 122 is formed. As can be seen from the measurement results, the average deposition rate of the deposit 121 in the anchorage 12 is 0.165 m / year on average before the formation of the deposit capturing unit 122, whereas after the formation of the deposit capturing unit 122, The average is 0.070 m / year, which is about 0.095 m / year lower. Due to such a decrease in the annual deposition rate, the maintenance dredging work interval of the sediment catching section 122 becomes approximately two years, and the maintenance dredging work interval of the inner portion of the anchorage 12 is extended to approximately 4 to 8 years. I was able to.

  Note that the depth DC and the width W of the deposit capturing unit 122 are not limited to the above-described example, and may be determined empirically based on the annual deposition amount of the deposit 121 in the anchorage 12, for example. Then, the volume necessary for the sediment catching part 122 is determined based on the annual deposition amount and the maintenance dredging work interval, and the depth DC and the width W with which the volume is filled are appropriately determined according to the topography of the anchorage 12. You may decide.

  As described above, according to the seabed structure of the harbor 1, the sediment trapping in which the sediment 121 is deeper than the seabed S on the inner side of the marginal area at the periphery of the seafloor 12 to lower the seabed. Since the section 122 is provided, it is possible to capture the sediment 121 such as sand and floating mud that has flowed in from the adjacent channel 14 and prevent the sediment 121 from flowing into the anchorage 12. As a result, the amount of deposit 121 deposited inside the peripheral edge of the anchorage 12 is reduced, so that the construction interval between maintenance dredging works is lengthened, and the maintenance cost of the harbor 1 is also reduced. Moreover, since the use restrictions of the harbor 1 during maintenance dredging work are reduced, it becomes possible to suppress a decrease in utilization efficiency and safety.

  Further, since the deposit capturing unit 122 is provided on the peripheral portion on the side of the navigation channel 14 adjacent to the anchorage 12, that is, on the peripheral portion side where the deposit 121 can move, for example, the land 2, the pier 11, etc. The construction of the deposit capturing part 122 on the peripheral edge on the structure side can be omitted, and the construction cost of the deposit capturing part 122 can be suppressed. Further, since the deposit capturing unit 122 is provided in a groove shape, that is, continuously along the boundary BL with the channel 14, the deposit 121 flowing from any position on the channel 14 is captured. It becomes possible.

  Even when the anchorage 12 is adjacent to a plurality of adjacent water areas such as the intake water area 13 and the channel 14, the adjacent water area is a water area from which the sediment 122 is discharged, or the water area in which the administrator is different from the predetermined water area. In this case, since the sediment trapping part 122 is provided on the adjacent water area side, it is not necessary to provide the sediment trapping part 122 on the unnecessary adjacent water area side, and the sediment trapping is performed at the boundary with all adjacent water areas. The construction cost can be reduced as compared with the case where the portion 122 is provided.

  Further, when the deposit capturing part 122 is provided in the anchorage 12, the deposit capturing part 122 is arranged so as to surround the anchorage 12, so that the inflow of the deposit 121 from all directions to the anchorage 12 is suppressed. Therefore, it is possible to lengthen the construction interval of the maintenance dredging work for the anchorage 12 that is frequently used as a port facility.

(Embodiment 2)
FIG. 6 is a plan view showing facilities of the harbor 4 according to this embodiment. This embodiment is different in configuration from the first embodiment in that a plurality of deposit capturing units 41 are provided discretely along the boundary with the adjacent water area, and a configuration equivalent to the first embodiment is as follows. The description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  In the anchorage 12, a plurality of deposit capturing parts 41 are discretely provided along the boundary BL with the channel 14. According to the present embodiment, the sediment 121 that has flowed into the anchorage 12 from the channel 14 can be captured by the plurality of deposit traps 41 that are discretely arranged, so that the water depth change of the anchorage 12 is suppressed. Therefore, it is possible to make the maintenance interval for the anchorage 12 longer than before.

  The deposit capturing unit 41 may be provided at predetermined intervals, or may be provided at arbitrary intervals according to the topography of the anchorage 12. In addition, the deposit capturing unit 41 may be installed more in the peripheral portion where the inflow amount of the deposit 121 is larger, and may be reduced in the peripheral portion where the inflow amount is smaller. The number of installations can be adjusted according to the situation.

  According to the seafloor structure of the harbor 4 of this embodiment, since the plurality of deposit capturing parts 41 are provided discretely along the boundary BL with the channel 14, they are provided at regular intervals or on the topography of the anchorage 12. In addition, the degree of freedom of arrangement becomes high, for example, by installing at arbitrary intervals, or by adjusting the number of installations according to the inflow amount of the deposit 121. Thereby, compared with the case where the deposit capturing part 41 is provided in the whole boundary with the channel 14, the construction area of the deposit capturing part 41 is significantly reduced, so that the construction cost, the construction period, and the like can be reduced.

(Embodiment 3)
FIG. 7 is a plan view showing facilities of the harbor 5 according to this embodiment. This embodiment is different from the first and second embodiments in that the deposit capturing part 51 is provided in the channel 14, and the same reference numerals are given to the same components as those in the first embodiment. The description is omitted.

  In the navigation channel 14, a deposit capturing part 51 is provided in a groove shape along the boundary BL with the anchorage 12. According to the present embodiment, since the deposit 121 flowing into the channel 14 from the anchorage 12 can be captured by the deposit capturing unit 51, a change in the water depth of the channel 14 can be suppressed, and the frequency of use as a port facility can be suppressed. Therefore, it is possible to make the maintenance interval of the maintenance dredging work for the high channel 14 longer than before.

  The deposit capturing part 51 may be provided on both peripheral edges of the channel 14, or may be provided on the adjacent water area side where the outflow of the sediment 121 is large, or on the adjacent water area side where the manager is different as in the first embodiment. Also good. Furthermore, as in the second embodiment, a plurality may be provided discretely along the boundary BL with the lodging 12.

  Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above embodiment, and even if there is a design change or the like without departing from the gist of the present invention, Included in the invention. For example, in the above embodiment, the deposit capturing part is provided so as to be in contact with the boundary with the adjacent water area, but the same effect can be obtained even if it is provided at a position away from the boundary.

  Furthermore, although the channel and anchorage have been described as examples of adjacent water areas, other water areas with a large amount of sediment inflow such as inflow water areas of rivers can also be adjacent water areas of the present invention. Moreover, although the sea port was demonstrated to the example, it is needless to say that it is applicable similarly to a lake and a river port.

1, 4, 5 Harbor 11 Pier 12 Staying place 121 Deposit 122, 4, 5 Deposit capturing part 13 Intake water area 14 Route 2 Land 21 Thermal power plant 31, 32 Ship

Claims (8)

A submarine structure to prevent the anchorage located adjacent to the port structure from being buried by sediment,
In a peripheral part of the bottom of the water in the anchorage so as to surround a side of the anchorage other than the side in contact with the structure, a deposit trapping part that traps the deposit deeper than the bottom of the water is provided.
The bottom structure of a port characterized by that. The deposit capturing unit is provided in a plurality of discretely along sides other than the side in contact with the structure of the anchorage ,
The water bottom structure of a harbor according to claim 1. The number of installed sediments is adjusted according to the amount of deposits flowing into the anchorage ,
The underwater structure of a harbor according to claim 2, wherein: The depth and width of the sediment catching unit is based on the annual amount of the sediment deposited on the anchorage and the interval between maintenance dredging works that are periodically performed to maintain the anchorage at a predetermined water depth. Determining the volume of the sediment trapping part necessary to maintain the anchorage at a predetermined water depth, and determining that the volume is satisfied,
The underwater structure of a harbor according to any one of claims 1 to 3, wherein A method of preventing underwater burial that prevents the bottom of the anchorage located adjacent to the port structure from being buried by sediments,
A sediment trapping part that traps sediment deeper than the bottom of the water is provided at the periphery of the bottom of the water in the anchorage so as to surround other than the side of the anchorage that contacts the structure.
A method for preventing underwater burial in a harbor. A plurality of the deposit capturing units are provided discretely along a side other than the side in contact with the structure of the anchorage.
The method of preventing underwater burial in a harbor according to claim 5. The number of installation of the deposit capturing unit is adjusted according to the amount of the deposit flowing into the anchorage.
The method of preventing underwater burial in a harbor according to claim 6. The depth and width of the sediment catching unit is based on the annual amount of the sediment deposited on the anchorage and the interval between maintenance dredging works that are periodically performed to maintain the anchorage at a predetermined water depth. Identifying a volume of the sediment trap necessary to maintain the anchorage at a predetermined depth and determined to satisfy the volume;
The method for preventing underwater burial in a harbor according to any one of claims 5 to 7.

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