JP2727340B2 - Method and apparatus for sprinkling sand on underwater ground - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a method for distributing sand to a submerged ground where sludge is deposited, with a minimum of environmental deterioration such as generation of turbidity and efficiently. The present invention relates to a method and apparatus for distributing sand to the underwater ground, which can disperse sand on a sand layer level.

[Conventional technology]

In closed waters such as harbors and lakes, pollutants, so-called sludge, have accumulated for many years, and nutrients and harmful substances elute therefrom, resulting in poor water quality. Improvement of water quality is a social demand. The direct method of water quality improvement is to remove the polluted sediment and bury it in a suitable disposal site, but the landfill site is in short supply compared to the huge amount of polluted sediment.
It is also difficult to implement because disposal costs are high. Therefore, recently, an economical method of preventing the elution of nutrients and harmful substances by covering the surface of the polluted sediment with sand has been implemented.

Also, in shellfish farms such as clams, the effects of dead shellfish appear on sandy ground even after long-term use,
In addition, the ground gradually hardens, which makes it unsuitable for aquaculture. As a countermeasure, a method of spreading the sand thinly and evenly, which is more economically advantageous than digging up the ground and improving it, has been implemented.

Furthermore, sand is scattered when creating artificial beaches.

Under the above-mentioned background, a conventional method of dispersing sand on the underwater ground will be described with reference to the drawings.

FIG. 5 and FIG. 6 are explanatory views showing the state of implementation of each example of the conventional method.

The conventional method shown in FIG. 5 is a method in which sand is mixed with water and sprayed. According to this conventional method, the sand S of the sand storage ship 1 is sucked in the direction of arrow a by the sand scattering pump 3 of the sand scattering ship 2 while stirring and mixing with jet water (not shown), and the spread width is passed through the inner pipe 4 of the ladder. Is sent to the widened sand disperser 5 and sprayed to settle the sand on the underwater ground G. Movement of the scatter site is performed, for example, by changing the position of the spar 6 in the front-rear direction by a swiveling method (referred to as a swing) of the sand scatterer 5 centered on the spar 6 driven into the ground. It has been performed by moving the entire apparatus in the direction of arrow b.

In the case of the conventional method using such spraying, since the sand is mixed with the jet water and sprayed, turbidity is severely generated and the turbidity generation range is wide. For this reason, the surrounding environment is adversely affected and turbidity makes it impossible to use a sounding device such as an acoustic sounding device during sand spraying. It is a target. Also, because of spraying, it must be sprayed from a certain height above the ground so as not to disturb the ground surface and the surface of the already-constructed part. It is difficult to spray evenly because it is susceptible to the flow, and the correction is inefficient.

The conventional method shown in FIG. 6 is a method in which sand is scattered in a scatter frame by a grab bucket. In this conventional method, a scatter type frame 11 which can be stretched up and down to the underwater ground held by a float 9 having a frame structure and a lower end frame 10 which is constrained to a sand scatter vessel 7 by a float restricting fitting 7a. The sand S grabbed by the grab bucket 13 from the sand storage boat 12 is dropped from the surface of the water, dispersed, and settled on the underwater ground G. The scatterer 7 can be moved forward and backward, left and right, for example, in the direction of the arrow c by the ship steering winch. In the case of the conventional method using the in-frame dispersal method, since the sand S is dropped from the surface of the water and dispersed, it takes time for the sand to settle down and settle down to the level of the sand layer. It is impossible to control the sand layer level using a sounding device such as an acoustic sounding device during construction. In addition, the uniformity of the scattered sand S was poor, and it was very inefficient to know and correct this after construction.

[Problems to be solved by the invention]

The present invention solves the above-mentioned disadvantages of the prior art, and it takes almost no time from dispersal of sand to formation of a sand layer to disperse sand on the water bottom,
Moreover, it is an object of the present invention to reduce the occurrence of turbidity, to enable the use of the measuring device immediately, and to enable the operation while controlling the sand layer level.

[Means for solving the problem]

As a result of various studies by the present inventors, a vibrator is attached to the top, and a casing in which sand is stored is sprayed with sand from the lower end thereof immediately near the underwater ground while the vibrator is operating, and fixed to the lower part of the casing. The present invention was completed by finding that the above problem could be solved by leveling at the lower edge of the cover and controlling the sand layer level by a sounding device attached to the cover.

Hereinafter, a method and an apparatus for spraying sand on the underwater ground according to the present invention will be described in detail.

In the method of spraying sand on the underwater ground according to the present invention, when performing the spraying of sand on the underwater ground with a sounding device so as to be at a predetermined sand layer level, a vibrator is attached to the top and a sand inlet is provided. Is a position higher than the water surface and has a gate which can be opened and closed inside by a predetermined height from the lower edge, and the lower edge is located at the same position as the predetermined sand layer level. It is movably installed, sand is charged from the sand inlet and stored on the gate in a state where the gate in the sanding apparatus is closed, and then the gate is opened while the vibrator is operated to remove the sand to the bottom. The sand spreading device is continuously or intermittently moved in the horizontal direction while being spread on the ground, and the spread sand is leveled at a predetermined sand layer level at its lower edge, and the level of the sand layer is measured and managed by a sounding device. Specially It is set to.

In this case, by measuring not only the sand layer level immediately after the sanding as described above but also the level of the ground immediately before the sanding as described above, the thickness and the leveling state of the sanding can be managed to improve the sanding. Can be implemented.

Next, an apparatus for spraying sand on the underwater ground according to the present invention suitable for carrying out the method of the present invention will be described with reference to the drawings.

FIG. 1 is a side view of a sand-spreading device for submerged ground according to the present invention, FIG. 2 is a front view thereof, and FIG. FIG. 4 is an explanatory side view showing a state in which the method of the present invention is performed, and FIG. 4 is an explanatory plan view of the same.

As shown in FIG. 1 and FIG. 2, the apparatus for spreading sand on the underwater ground according to the present invention comprises a casing 15, a gate 16, and a sounding device 18 such as an acoustic sounding device. Casing 15
The upper part is almost cylindrical and has a sand inlet 15a at a high position above the water surface, the vibrator 20 is attached to the top, and the lower part forms a widened part 15b of a widened shape and the lower part Gate cover 17 is fixed. The shape of the upper portion of the casing 15 may be circular or any other shape in addition to a square cross section as in the illustrated example, and the shape of the widened portion 15b may be different from that in the case where the width is expanded only in one direction as in the illustrated example. The width may be widened in all directions, may be widened in a tapered shape as shown in the figure, or may be widened stepwise. The sand S is mainly stored in the widened portion 15b. Further, in order to improve the efficiency of the sand scattering, the sand spreading device 14 is moved at right angles to the widening direction of the widening portion 15b to spray the sand. The gate 16 is attached to the lower end of the casing 15 and functions to freely open and close the lower end opening of the casing 15. In order to make the gate 16 openable and closable in this way, in the illustrated example, the end of the gate 16 attached to the casing 15 so as to be rotatable with a bracket 16a can be operated from above the water (pipe not shown). To open and close. The gate cover 17 is open only at the lower side surrounding at least the gate 16, and is attached to the casing 15 so that the lower end edge 17a is located at a position lower than the gate 16 by a predetermined height. Since the gate cover 17 is opened only downward, the lower edge 17
The inside of the gate cover 17 above a is closed. When the inside of the gate cover 17 above the gate 16 is formed with an air storage space 17b as shown in FIG. 1, it is preferable because the sand S falls down from the casing 15 together with the vibrator 20 as described later. . The sounding device 18 is attached to the outside of the gate cover 17 downward.
Since the sounding device 18 is required to measure the sand layer level in the management, the direction of movement of the sand scattering device 14, that is, the direction perpendicular to the direction of widening of the widening portion 15b of the casing 15 (the direction of arrow d in FIG. 1). Gate cover at the rear for progress
It is good to attach along the side of 17 and it is preferable to use two or more pieces as shown in FIG. More preferably, as shown in FIG. 1, if the sounding device 18 is attached to both of the above-mentioned side surfaces, the level of the underwater ground G immediately before the sand spraying can be measured, so that the thickness and the leveling state of the sand layer are controlled. You can do it. Preferably, as shown in FIG. 1 and FIG. 2, when a sand detection sensor 19 composed of a strain gauge type earth pressure gauge or the like is attached to the inside of the lower end of the gate cover 17, sand in the casing 15 or clogging of sand can be prevented. For example, it is possible to detect an abnormality of sand falling into the gate cover 17. If the vibrator 20 is attached to the top of the casing 15 as shown in FIGS. 1 and 2, the sand S can be smoothly lowered in the casing 15 and the sand S can be removed from the gate 16.
In this case, if the air reservoir space 17b is provided in the upper part of the gate cover 17 as described above, a sudden change in the water pressure in the gate cover 17 caused by the vibration of the vibrator 20 is absorbed, and the sand is scattered. This is preferable because it can be performed smoothly. In addition,
In order to hold the casing 15 in use, it is preferable to attach a hanging member 21 to the top of the casing 15 via a coil spring 22.

(Implementation method and operation)

In order to carry out the above-described method of the present invention using the above-described underwater sand distribution apparatus 14 according to the present invention, first, as shown in FIGS.
14 can be adjusted vertically and the widened portion 15b of the casing 15
Is held so as to be substantially perpendicular to the moving direction of the sandblasting ship 23. This holding can be performed appropriately,
For example, as shown in the illustrated embodiment, a winch wire 25 wound around a vertical winch on a sandblasting ship 23 is tightly attached to a hanging metal fitting 21, and a support 26 protruding upward from the water surface from the sandblasting ship 23, for example, an inclined jib crane. Sprinkling equipment 14 from the tip of
Of the casing 15 and a restraining device 27 protruding from the sand scattering boat 23 at a substantially central portion of the casing 15 so as to be slidable only in the vertical direction. Then, the scattered ship 23 is towed to the construction site, and the marine vessel anchor 30 is driven into the underwater ground G as shown in FIG. Fix the position. When the above preparations are completed, the winding up and down winch 24 will be used
By moving 14 up and down, the lower edge 17a of the gate cover 17 is adjusted to a predetermined sand layer level position. Next, the gate 16 is closed, and the sand S in the sand storage hopper 28 on the scatterer 23 is charged into the casing 15 through the sand inlet 15a by the conveyor 29, and the sand S is sufficiently filled to fill the widened portion 15b of the casing 15. To store. Next, when the gate 16 is opened while operating the vibrator 20 attached to the top of the casing 15, the casing
The sand S in 15 flows out downward, but the gate 16
, And the expansion is restricted by the gate cover 17, as shown in FIG.
Sprinkled on top. Therefore, unlike the case of dropping from a high place, there is no sedimentation time, and almost no turbidity occurs. Even if slight turbidity occurs, its diffusion is prevented by the gate cover 17. When an appropriate amount of the sand S is deposited on the underwater ground G, the boat maneuvering winch 31 is driven to move the sand scattering device 14 together with the sand scatter ship 23 in the direction of arrow e in FIG. The deposited sand S is leveled to a predetermined sand layer level. The lowering of the sand S from the casing 15 and the movement of the sand sprinkler 14 can be performed continuously or intermittently so that the respective amounts are adjusted and the two are balanced. And such sand distribution state is managed by the sounding device 18 on the rear side in the traveling direction, and when the sounding device 18 is also mounted on the front side of the traveling, the thickness and leveling state of the sand can also be managed. . Further, if the sand detection sensor 19 is attached, it is possible to manage abnormalities of sand dropping. Also,
When the air reservoir space 17b is provided above the inside of the gate cover 17, sand can be smoothly removed while avoiding a sudden change in water pressure in the gate cover 17 due to vibration of the vibrator 20. Since the lower end edge 17a of the gate cover 17 in the direction in which the gate cover 17 is widened is leveled, the sand scatter can be efficiently performed with a wide sand scatter width W as shown in FIG.

〔The invention's effect〕

As described in detail above, the method and the apparatus for sand-spreading on the underwater ground according to the present invention, the sand once stored in the sand-spreading apparatus is spread from the gate located immediately near the underwater ground by the gate cover in a state where the spread is restricted. Waiting for sedimentation of the scattered sand by scattering the sand directly on the underwater ground and using the vibrator to effectively level the vibration at the lower edge of the gate cover at the predetermined sand layer level Necessity is eliminated and turbidity hardly occurs. Even if slight turbidity occurs, the diffusion is prevented by the gate cover.
Therefore, there is no need to worry about environmental pollution, and it is possible to control the sand layer level, spraying thickness, leveling condition, etc. using a sounding device during construction. Good sanding can be implemented. And since there is no need for modification after dispersal, there is no need to use extra sand, the efficiency is greatly improved, the economic effect is great, and the industrial value is very large.

[Brief description of the drawings]

FIG. 1 is a side view of a sand-spreading device for submerged ground according to the present invention, FIG. 2 is a front view thereof, and FIG. FIG. 4 is an explanatory side view showing a state in which the method of the present invention is performed, FIG. 4 is an explanatory plan view of the same, and FIGS. In the drawings: 1… Sand storage boat 2… Sand dispersion boat 3 …… Sand dispersion pump 4 …… Ladder inner tube 5 …… Sand dispersion machine 6… Spard 7 …… Sand distribution boat 7a …… Float restraining bracket 8… ... Spraying frame 9 ... Float 10 ... Bottom frame 11 ... Skirt type membrane 12 ... Sand storage boat 13 ... Club bucket 14 ... Spraying device for underwater ground according to the present invention 15 ... Casing 15a ... … Sand inlet 15b… Wide section 16… Gate 16a… Bracket 16b… Gate opening and closing cylinder 17… Gate cover 17a… Bottom edge 17b… Air reservoir space 18… Depth detector 19… Sand detection Sensor 20 Vibrator 21 Hanging bracket 22 Coil spring 23 Sand scatter boat 24 Winding vertical winch 25 Winch wire 26 Support column 27 Restraining device 28 Sand storage hopper 29 Conveyor 30… Ship control anchor 31… Ship control winch 32 …… Ship control wire a, b, c, d, e …… Arrow G …… Bottom ground S …… Sand W …… Sand splay width

Claims (6)

(57) [Claims] 1. A method for distributing sand to a submerged ground with a sounding device so as to maintain a predetermined sand layer level, wherein a vibrator is attached to the top and a sand inlet is located at a position higher than the water surface. A sand dispersing device having a gate which is openable and closable inside by a predetermined height above the lower edge so that the lower edge is located at the same position as the predetermined sand layer level is installed movably in the horizontal direction, After the sand in the spraying device is closed and the sand is thrown in from the sand inlet and stored on the gate, the gate is opened while the vibrator is operated, and the sand is sprayed on the underwater ground. The underwater ground characterized by moving the spraying device continuously or intermittently in the horizontal direction to level the sand spread at the lower edge thereof to a predetermined sand layer level, and managing the level of the sand layer by measuring with a sounding device. Sand to Cloth method. 2. The method according to claim 1, wherein the thickness of the scattered sand and the leveling state are controlled by comparing values measured by a sounding device immediately before and immediately after the scattered sand. 3. An apparatus for spraying sand (S) onto a submarine ground (G) so as to maintain a predetermined sand layer level by a sounding device (18), wherein the upper part is substantially cylindrical and the lower part is widened. Sand inlet (15a) at a position higher than the upper water surface
A casing (15) having a vibrator (20) mounted on the top thereof, and a predetermined height above a lower edge (17a) of a gate cover (17) fixed to a lower portion of the casing (15). An openable gate (16) installed inside the gate cover (17);
And a sandblasting device (18) mounted downward on the outside of (7). 4. The apparatus according to claim 3, wherein an air reservoir space (17b) is formed inside the gate cover (17) above the gate (16). 5. The apparatus according to claim 3, wherein at least two sounding devices are provided along the widened side surfaces of the lower portion of the casing. 6. The apparatus according to claim 3, wherein a sand detection sensor (19) is mounted inside the lower end of the gate cover (17).