JPH0346603B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is suitable for use in spreading sand onto soft underwater mud to cover the surface with a sand layer of uniform thickness. This relates to the sand covering method.

(Prior art) On the seabed of a beach where sludge is deposited,
When sludge is reclaimed, the bottom surface of the water may be covered with a sand layer as a drainage layer between the layers.

In such cases, conventionally, sand was spread by dropping sand into the water from the sand-spreading section of a sand-sprinkling boat.

(Problem to be Solved by the Invention) However, with this method of dispersing sand, the sand falls in a concentrated manner and the falling speed is high, causing it to sink into the mud surface and spread almost all over the water bottom surface. There was a problem that it was not possible to form a sand layer of various thicknesses.

An object of the present invention is to provide an underwater sand covering method that allows sand to be spread almost uniformly.

(Means for Solving the Problems) The underwater bottom encrusting method according to the present invention involves injecting air from a large number of air outlets of an air injection tool disposed near the underwater bottom to raise air bubbles in the water. This method is characterized in that sand is spread from a sand spreading tool on the water surface to the location where the air bubbles rise.

(Function) When sand is sprinkled from above the water surface at a place where air bubbles are rising, the air bubbles slow down the sedimentation rate of the sand that is falling into the water, and the sand is blown up into pieces, resulting in extremely dangerous sand. It will be deposited evenly with the structure.

(Example) Examples of the present invention will be described in detail below with reference to FIGS. 1 to 4. As shown in the figure, a sand spreading tool 3 is floated on a water surface 1 by a floater 2. The sand spreading tool 3 is equipped with a sand spreading pipe 4, and a large number of sand spreading holes 5 are provided in two rows on the lower surface of the sand spreading pipe 4, and an angle member 6 is provided in the pipe between the rows. Sand 8 is supplied from the sand supply pipe 7 together with water in the form of a slurry, and is discharged from each sand dispersion hole 5 for dispersion.

A winch 9 is mounted on the floater 2, and a wire rope 10 is pulled out from the winch 9.
is lowered into the water via rollers 11, and an air injection device 12 is suspended and supported at its lower end.
The air injection device 12 has air injection devices 13 connected and communicated with each other in a grid pattern, and a large number of air discharge ports 14 are provided on the lower surface of each air injection pipe 13.
Floater 2
From the upper air compressor 15 to the air hose 16
Air is supplied through the air outlet 14, and the air is discharged from each air outlet 14.

As shown in the figure, the air injection device 12 is used to spray floating mud 1 on the bottom of the water.
7, and correspondingly position the sand scattering tool 3 on the water surface 1. In such a state, while towing it with a ship etc. as appropriate so that both of them move in conjunction,
Sand 8 is spread into the water through the sand dispersion hole 5 of the sand dispersion pipe 4, and air is discharged from the air discharge port 14 of the air injection pipe 13. The discharged air becomes bubbles 18 and rises in the water. Due to the upward flow of the air bubbles 18, the sedimentation speed of the sand 8 spread from above the water decreases, and the sand 8 is lifted up and dispersed. As a result, the sand 8 is dispersed and deposited very slowly, making it possible to cover the floating mud 17, which has almost no supporting force, as a thin bulk sand layer 19. The volumetric sand layer 19 can be used to increase or decrease the amount of spraying from the sand spreading tool 3 or to increase or decrease the amount of sand spreading from the sand spreading tool 3 and the air spraying tool 1.
It can be increased or decreased by increasing or decreasing the moving speed of 2.

(Effects of the Invention) As explained above, in the present invention, sand is spread where air bubbles are rising from the water, so the upward flow of air bubbles slows down the sedimentation speed of the sand, and the sand is lifted up and dispersed. However, sand can be deposited very slowly and uniformly. Therefore, it is possible to cover a thin layer of sand even on floating mud that has almost no supporting force.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of the implementation state of the underwater sand covering method according to the present invention, FIGS. 2 and 3 are a side view and a vertical sectional view of a part of the sand dispersion pipe, and FIG. 4 is an air injection FIG. 5 is a bottom view of an example of the tool, and a vertical sectional view of an example of the air injection pipe. 1...Water surface, 2...Floater, 3...Sand spreading tool, 4...Sand spreading pipe, 5...Sand spreading hole, 8...
Sand, 10...Wire rope, 12...Air injection device, 13...Air injection pipe, 14...Air discharge port,
17...Floating mud, 18...Air bubbles, 19...Volume sand layer.

Claims (1)

[Claims] 1. Injecting air from a number of air outlets of an air injection tool placed near the water bottom to cause air bubbles to rise into the water, and then scattering sand from a sand spreading tool on the water surface to the location where the air bubbles rise. A distinctive underwater sand covering method.