JP5281025B2 - Sand covering device and sand covering method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for sand covering, which do not pollute an water area. <P>SOLUTION: Slurry prepared by mixing water and sand is discharged toward the bottom of water with a substantially horizontal flow. Water in the amount substantially equal to the amount of the discharged sand is suctioned from the vicinity of the discharge port, and is used to make the slurry. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a sand covering apparatus and a sand covering method.

  The sand-capping method is to obtain the same effect as the dredging method by covering the sludge accumulated on the water bottom with sand or the like.

As a sand-capping method, a method of dropping sand directly onto a water bottom from a work ship is known.
Alternatively, as shown in FIG. 9, there is a conventional method in which the sand covering material supplied from the work ship e is sprayed toward the bottom mud c layer of the water bottom through the discharge pipe a, and the upper surface of the bottom mud c is covered with sand b. It is made from.

Further, Patent Documents 1 and 2 disclose a method for supplying sand from a ship toward a bottom of a water using a tremy tube or a tubular chute to cover sand.
Furthermore, a sand covering method described in Patent Document 3 that improves this point is also known.

  In the apparatus shown in Patent Document 3, as shown in FIG. 10, slurry-like earth and sand are supplied toward the bottom of the water, the flow direction of the earth and sand is changed a plurality of times before the slurry reaches the bottom of the water, and the flow velocity is reduced. The bottom of the water is covered with the discharged earth and sand. Therefore, it has an advantage that a sand covering layer can be formed without disturbing the bottom mud.

JP 62-41815 A Japanese Unexamined Patent Publication No. 63-40021 Japanese Patent Laid-Open No. 2005-23750

The conventional water bottom sand-capping method and dredging method described above have the following problems.
(1) During the sand-capping operation, fine particles contained in the sand-covering sand diffuse into the water and cause turbidity.
(2) When sand covers the existing bottom mud, the bottom mud rises and diffuses to disturb the surrounding water.
(3) Since the sand covering material enters the inside of the soft bottom mud due to the falling speed, it is necessary to form a considerable amount of sand layer in order to completely cover the bottom mud with the sand covering.
(4) For the same reason, the sand-capping material sinks into the bottom mud layer, the bottom mud upper surface becomes turbulent, the bottom mud rises and becomes cloudy in the water area, or the bottom mud that rises above the sand-covered layer sinks A bottom mud layer may be formed on the sand cover layer.
(5) Since the construction is carried out from the water, the sand cover thickness is uneven, and the uneven mud sand tends to cause the bottom mud to slip and is difficult to manage. Further, since the layer thickness is not uniform, it is necessary to add a large amount of sand to satisfy the minimum required thickness.
(6) Even in the apparatus shown in Patent Document 3, there still remains a problem that fine particles contained in the sand-capping material do not settle quickly and give turbidity to the surroundings. Further, since the sand cover concentrates and settles near the center of the apparatus, it is uneconomical to move the sand supply position frequently in order to obtain a sand cover layer having a uniform thickness.

In order to solve the above-described problems, a first invention of the present application is a sand covering device for covering a water bottom, a supply device for supplying sand covering material to a pipe line by free fall, and a water bottom surface. A discharge device arranged so as to face the pipe , wherein the pipe line connects the supply device and the discharge device, and the pipe line connects the supply device and the discharge device. And a water absorption pipe that connects between the discharge device and the supply device, and a pump that circulates the water inside the pipe is provided in the water absorption pipe and flows in a certain direction to the water inside the pipe the applied, the water bottom side of the discharge device, provided the outlet of the slurry obtained by mixing water Kutsugaesuna material, in the vicinity of the outlet, a water inlet for taking in water provided, the slurry to water of a specific gravity using the size, thereby dropping the slurry from the discharge port It is an feature.

The second invention of the present application uses a pump that circulates water inside the pipe,
The slurry is dropped from the discharge port using free fall of the sand-capping material and the flow of water in the pipe line by a pump .

The third invention of the present invention is characterized in that a sand basin is installed in the middle of the pipe.

According to the present invention, at least one of the following effects can be obtained.
(1) A sand covering layer can be formed without disturbing the bottom mud. For this reason, water quality hardly deteriorates. Moreover, a sand covering layer can be formed reliably.
(2) The sand-covering material is mixed with water to form a slurry, and the sand-covering operation is performed near the bottom of the water and in a horizontal direction. Therefore, even if it is a soft bottom mud, it is hard to generate | occur | produce of sand, and it is possible to form a thin and uniform sand covering layer on the surface of the bottom mud.
(3) Since sand is reliably covered on the bottom mud, the dissolved oxygen consumption of sludge and the elution amount of nutrient salts such as nitrogen and phosphorus are suppressed, and the eutrophication of lake water is weakened.
(4) The surface layer of the water bottom after sand covering becomes a uniform sand covering layer made of sand or sandy soil. For this reason, since the environment of a water bottom will be in a favorable state of sandy soil system, it will be improved as a habitat for freshwater plants and bottom organisms.
(5) Since the excess slurry that has not dropped from the discharge port of the apparatus is absorbed and circulated, there is no diffusion to the surroundings, and the occurrence of turbidity can be suppressed.
(6) Elution of the pollutant from the sludge can be suppressed by thinly covering the soft sludge accumulated on the water bottom with sand or the like.
(7) Since sand can be covered to a uniform thickness on average, it is economical because it is not necessary to make a surplus more than the necessary sand covering thickness.
(8) Since the scale of the sand covering device can be easily increased, if it is designed according to the application, sand covering work can be efficiently performed in a short time.
(9) If a sedimentation place is installed, it is possible to remove fine particles that are contained in the sand-capping material and are not suitable for sand-capping, and water pollution can also be suppressed in this respect.

Explanatory drawing of the Example of the sand covering apparatus of this invention. Explanatory drawing of the other Example of a supply apparatus. Explanatory drawing of the Example of discharge | release apparatus. The perspective view seen from the other Example of the discharge | release apparatus. The perspective view seen from the discharge | release apparatus from the bottom. Explanatory drawing of the implementation state of the sand-capping method. Explanatory drawing of the other Example of the sand covering method. Explanatory drawing of the other Example of discharge | release apparatus. Explanatory drawing of the Example of the conventional sand covering method. Explanatory drawing of the other conventional sand-capping method.

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

<1> Principle of sand covering method In the sand covering method of the present invention, slurry is used.
This slurry is a material that can be fluidly transported through a pipeline by mixing water with a sand covering material such as earth and sand.
This slurry is discharged toward the bottom of the water with a flow in a substantially horizontal direction applied to cover the sand.
Here, “substantially horizontal” means that the earth and sand discharge direction in the invention described in the prior art is substantially vertical, and does not mean that it is exactly horizontal.
Further, in the present invention, the slurry is dropped from the discharge port by utilizing the weight of the specific gravity of the slurry with respect to water, so that the slurry discharge flow rate is smaller than the horizontal flow rate in the discharge device.
Then, an amount of water approximately equal to the amount of the discharged slurry is sucked from the vicinity of the discharged position, and this is used for manufacturing a new slurry.
Next, an apparatus that actually functions the above construction method will be described.

<2> Overall Configuration FIG. 1 is an explanatory diagram of an embodiment of the sand covering apparatus of the present invention.
The sand-capping device of the present invention is constituted by a sand-capping material supply device 1, a discharge device 2, and a conduit 3 in which the supply device 1 and the discharge device 2 are continuous.

<3> Supply Device The supply device 1 is a device that supplies sand-covering material C such as sand to the water circulating in the pipeline 3.
For example, a hopper that is an open container is used, and the sand-capping material C charged into the hopper is supplied to the pipeline 2 by free fall.
The amount of sand to be supplied is determined by attaching a valve (not shown) to the lower end of the supply device 1 and adjusting the amount of sand falling by the amount of opening of this valve.
As another embodiment, a stirring device 11 can be provided inside the supply device 1 to mix water and sand covering material with stirring (FIG. 2).

<4> Discharge device The discharge device 2 is a hollow container placed facing the water bottom.
As the shape of the discharge device 2, a single or a plurality of cylindrical members (FIGS. 1 and 3), a rectangular container (FIGS. 4 and 5), other shapes, or a combination thereof can be adopted.
If the discharge device 2 has a hollow rectangular shape (FIGS. 4 and 5) or is configured by a plurality of cylinders (not shown), it is possible to evenly spread sand covering in a wide range in the transverse direction. .

<4.1> Discharge Port One or a plurality of slurry discharge ports 21 are opened on the lower surface of the discharge device 2, that is, on the water bottom side.
The discharge port 21 in this embodiment is simply formed by opening an outer shell of a member constituting the discharge device 2.

<4.2> Water inlet A water inlet 22 for taking in water is opened in the vicinity of the discharge port 21.
The water inlet 22 in the present embodiment is also a portion formed by simply opening the outer shell of the member constituting the discharge device 2.
The positional relationship between the discharge port 21 and the water intake port 22 is preferably such that the discharge port 21 is opened on the lower surface of the discharge device 2 and the water intake port 22 is opened on the upper surface (FIGS. 1 and 3).
The water inlet 22 can suppress the occurrence of turbulence due to vortices by opening it smaller than the outlet 21.
By providing the water suction port 22, external water can be sucked into the discharge device 2 by the negative pressure of flowing water flowing in the discharge device 2.

<5> Effect of water absorption By appropriately designing the size and arrangement of the water intake port 22 of the discharge device 2, the same amount of water as the slurry discharged from the discharge port 21 and dropped can be sucked.
Then, generation | occurrence | production of the vortex in the periphery of the discharge | release apparatus 2 can be suppressed, and the rising and spreading | diffusion of the bottom mud A and the covering sand B can be suppressed.
In addition, the slurry that has not fallen from the discharge port 21 is supplied together with water sucked from the water suction port 22 and water for slurry generation.
With this function, it is possible to suppress discharge of excess slurry to the outside, and it is possible to suppress turbidity generation and diffusion around the sand covering position.

<6> Pipe line and pump The pipe 3 connects the supply device 1 and the discharge device 2 so that slurry and water communicate with each other.
Then, a pump 33 is provided at any position in the pipeline 3, and the pump 33 gives a flow in a certain direction to the water inside the pipeline 3.
The pump 33 for circulating the slurry may be installed at any position in the sand supply pipe 31 or the water absorption pipe 32, and the installation location can be determined according to the performance of the pump.

<7> Sand supply pipe This pipe line 3 is constituted by a sand supply pipe 31 and a water supply pipe 32.
The sand supply pipe 31 is a pipe material that connects the supply device 1 and the discharge device 2 and is used for the flow from the supply device 1 to the discharge device 2.
Since the sand supply pipe 31 is connected between the supply device 1 and the discharge device 2, the slurry in a state where water and sand are mixed is transported to the discharge device 2.

<8> Water Absorption Pipe On the other hand, the water absorption pipe 32 is used for the flow from the discharge device 2 to the supply device 1 by connecting the discharge device 2 and the supply device 1.
Since the water absorption pipe 32 connects between the discharge device 2 and the supply device 1, the water sucked from the suction port 22 of the discharge device 2 is mainly transported to the supply device 1.

<9> Installation of Release Device As shown in FIG. 6, the above-described release device 2 can be suspended from the work platform ship 4 with a crane or the like.
Or as shown in FIG. 7, the structure which attaches the floater 6 to the discharge | release apparatus 2, and gives buoyancy to the apparatus itself can also be employ | adopted.
Further, the supply device 1 for supplying the covering sand can be installed on a work table ship as shown in FIG. 6, but the supply device 1 is installed on the ground as shown in FIG. It is also possible to adopt a configuration in which long pipes are connected.

<10> Sand settling basin When the sand-capping material contains fine particles or particles having a small specific gravity, these particles do not easily settle and thus continue to circulate in the pipeline 3 without falling from the discharge port 22.
In this case, as shown in FIG. 5, a sand basin 5 can be installed in the middle of the pipe 3 and settled there to remove these fine particles.

<11> Sand-covering process The sand-covering process performed using said apparatus is demonstrated referring FIG.
Sand covering material C is put into the supply device 1.
At the same time, the pump 33 is operated to circulate water in the pipe 3.
This water is supplied into the pipeline from a large number of water inlets 22 opened to the discharge device 2.
The sand covering material C is supplied into the pipe line by its own weight, mixed with water to become a slurry, and reaches the discharge device 22 through the sand supply pipe 31.

<12> Release of sand-covering material Most sand-covering material that reaches the discharge device 2 from the sand supply pipe 31 falls from the discharge port 21 of the discharge device 2 toward the bottom of the water as slurry, and becomes sand-covered B.
At this time, since the discharge device 2 is arranged in parallel with the bottom of the water, the slurry falls from the discharge port 21 in a state where a substantially horizontal flow is applied to the slurry.
Therefore, unlike the vertical input by the conventional apparatus, the penetration force to the bottom mud A is small, so that the sand covering material does not easily enter the mud and it is difficult to wind up the fine mud particles of the bottom mud A.
Therefore, the rising and diffusion of the bottom mud A can be suppressed.
Further, as described above, since the sand covering material is discharged in a direction close to the horizontal, it is easy to form a thin horizontal sand covering layer, which is more accurate than the conventional apparatus and method for dropping in the vertical direction. A thin sand covering B can be formed.

<13> Water absorption step An amount of water substantially equal to the amount of slurry discharged from the discharge port 21 is sucked into the discharge device 2 from the water intake port 22.
Since the water inlet 22 is in the vicinity of the discharge port 21, it is possible to suck water in the water area that tends to be turbid due to the influence of the discharge port 21 into the discharge device 2.
Therefore, generation | occurrence | production of the turbidity at the time of discharge | release of a sand covering material can be suppressed.
Moreover, the sand covering material that has not fallen from the discharge port can be circulated through the pipeline 3 together with newly sucked water and dropped from the discharge port 21 again.

  Other forms of the discharge port 21 and the water suction port 22 will be described with reference to FIG.

The discharge port 21 and the water absorption port 22 in the present invention can adjust the covering sand discharge performance and water absorption performance by appropriately designing the shape, size, arrangement form, and the like.
For example, a part of the outer shell constituting the discharge device 2 is cut, and the cut portion is bent slightly toward the outside of the discharge device 2 to provide the guide portions 21 and 221 to form the discharge port 21 and the water suction port 22. You can also

  The bent portion 212 forming the guide portion 211 is configured to be positioned on the near side with respect to the flow of water in the discharge device 2. On the contrary, the bending part 222 which forms the guide part 221 is configured to be located on the back side with respect to the flow of water in the discharge device 2.

According to the present embodiment, since the guide portion 211 that forms the discharge port 21 guides the slurry in the horizontal direction, it is possible to discharge the covered sand that gave a more horizontal flow, and to disturb the bottom mud more. A sand-covering layer can be formed.
Moreover, since the guide part 221 which forms the water absorption port 22 guides water at the time of taking in water, water can be taken in into a pipe line more efficiently.

  In addition, when the sand covering device is moved in the direction opposite to the flow of water in the discharging device 2, the sand covering with a further horizontal flow can be discharged, and a thinner sand covering layer can be formed. It is also possible to take water into the pipeline more efficiently.

DESCRIPTION OF SYMBOLS 1 Supply apparatus 2 Discharge apparatus 21 Discharge port 22 Water intake port 3 Pipe line 31 Sand supply pipe 32 Water absorption pipe 4 Work table ship 5 Sand basin 6 Floater

Claims (3)

A sand-capping device for covering the bottom of the water,
A supply device for supplying sand-clad material to the pipeline by free fall ;
A discharge device arranged to face the bottom of the water,
The conduit connects the supply device and the discharge device ,
The pipe line is a sand supply pipe connecting the supply device and the discharge device ,
While comprising a water absorption pipe connecting the discharge device and the supply device
A pump that circulates water inside the pipe line is provided in the water absorption pipe to give a flow in a certain direction to the water inside the pipe line ,
On the water bottom side of the discharge device, a discharge port for slurry mixed with sand covering material and water is provided,
In the vicinity of the discharge port, a water intake port for taking in water is provided,
The sand covering apparatus , wherein the slurry is dropped from the discharge port by utilizing the specific gravity of the slurry with respect to water . Use a pump to circulate the water inside the pipeline,
The slurry is dropped from the discharge port by using the free fall of sand-capping material and the flow of water in the pipe line by a pump,
The sand covering apparatus according to claim 1 . 2. The sand covering apparatus according to claim 1, wherein a sand basin is installed in the middle of the pipe.

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