JP2799525B2 - How to lay a civil engineering net - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for laying a civil engineering net on soft ground under water.

[0002]

2. Description of the Related Art Conventionally, in a reclamation work on a shore or the like, in order to strengthen the soft ground on the seabed, as shown in FIG. Laying method is adopted.

[0003]

However, in the above-mentioned laying method, when the civil engineering net 1 is pulled out by the tugboat 2, the civil engineering net 1 bends by its own weight as shown in FIG. In some cases, the net 1 is entangled with the sludge on the seabed 3 and a large resistance force acts, so that there is a problem that it is difficult to pull out the civil engineering net 1 from the middle or the civil engineering net 1 is broken.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a laying method which can be easily pulled out to the water surface without breaking a civil engineering net.

[0005]

In order to achieve the above-mentioned object, a laying method according to the present invention is directed to a method of laying a net for civil engineering on a net anti-sinking device formed by connecting a large number of floats and drawing the net to the water surface on soft ground. After that, the net anti-sinking device is removed.

[0006]

According to the laying method of the present invention, since the civil engineering net is pulled out while floating on the water surface on the net anti-sinking device, it hardly receives the water resistance under the water surface and comes into contact with soft ground. Since there is no such work, it is extremely easy to pull out the civil engineering net, and there is no fear that the civil engineering net is broken. Then, when the net for civil engineering is pulled out and the net preventing device is removed, the net for civil engineering sinks by its own weight and is laid on the surface of the soft ground.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view of an embodiment of the laying method of the present invention, FIG. 2 is a plan view showing a state in which a civil engineering net is pulled out, and FIG. 3 is a partial perspective view of the net anti-sinking device.

In the figure, 1 is a civil engineering net, 2 is a tugboat, 3 is soft ground on the sea floor, 4 is a water surface, 5 is a net anti-sunken device, and 6 is a feeder installed on the shore. The civil engineering net 1 and the net anti-settling tool 5 are fed out from the upper and lower rolls 6.

As the civil engineering net 1, a high-strength synthetic resin net or a synthetic fiber net impregnated with a resin, which has been widely used for laying nets, is used. The net has a mesh size of about 5 to 50 mm. Those having a width of about 5 to 10 m are preferably used.

On the other hand, the net anti-settling device 5 is such that floats 5a longer than the net width are arranged at intervals of several meters and both ends of each float 5a are connected in a ladder shape by two ropes 5b, 5b.
The tip of each rope 5b is a rod 5 with a tow rope 5c.
It is fixed to d. The above-mentioned float 5a has a tubular or pillow shape with both ends closed, and is made of an airtight cloth coated with fluorine or silicon.
Each float 5a is provided with a hook 5e at each end, and is attached to the rope 5b by detachably engaging the hook 5e with a connection fitting 5f fixed to the rope 5b. A valve 5g is provided at one end of each of the floats 5a, and the buoyancy can be adjusted by increasing or decreasing air through the valve 5g.

In the laying method of this embodiment, first, the above-mentioned civil engineering net 1 and the net anti-settling device 5 are drawn out from the upper and lower rolls of the feeder 6, and the tow rope 5c of the net anti-settling device 5 is attached to the tugboat 2. At the same time, the tip of the civil engineering net 1 is removably temporarily fixed to the rod 5d at the tip of the net anti-sinking device 5, and the civil engineering net 1 is superposed on the net anti-sinking device 5 and the water surface 4 is pulled by the tugboat 2. Pull out. Then, the valve 5g of each float 5a of the net anti-settling device 5 is opened to release air, the net anti-settling device 5 is removed, the civil engineering net 1 is settled by its own weight, and laid on the surface of the soft ground 3 on the sea floor.

When the civil engineering net 1 is overlaid on the net preventive device 5 and pulled out as described above, the civil engineering net 1 floats on the water surface 4 by the buoyancy of the float 5a of the net preventive device 5, so that the water resistance under the water surface is reduced. And is not entangled with the soft ground 3 on the seabed, so that the work for pulling out the civil engineering net 1 is facilitated. There is no need to worry that the entanglement will make it difficult to pull out from the middle and that the civil engineering net will be broken. When the net 5 is removed by removing the air from the float 5a as described above, the buoyancy of the float 5a is reduced, so that the work for removing the net preventive tool 5 can be easily performed.

In the embodiment described above, the civil engineering net 1 and the net anti-settling tool 5 are fed using the feeding machine 6,
Instead of using such a feeding machine 6, the wound civil engineering net 1 and the net anti-settling device 5 may be fed while being unwound by hand. In addition, the net anti-sun protection device is not limited to the one in this embodiment, and various net anti-sun protection devices having different types of floats and different connection structures can be used.

FIG. 4 is a plan view showing another example of such a net anti-settling device having different types of floats and different connection structures, which is a short length made of a resin foam having a high expansion ratio such as styrene foam. A ladder-shaped net anti-sinking device is formed by inserting a cylindrical float 5h into a rope 5i, arranging the ropes 5i through which the float 5h is inserted in parallel at intervals of several meters and connecting the two ropes 5b, 5b on both sides. It is what it was. Other configurations are the same as those of the above-described embodiment, and the same members are denoted by the same reference numerals and description thereof will be omitted. Even when such a net anti-sunken device is used, the object of the present invention can be achieved because the civil engineering net 1 can be pulled out while being floated on the water surface 4, but the buoyancy can be adjusted like the net antisun device 5 of the above embodiment. Since there is no such work, the work of removing the net anti-sinking device after the civil engineering net 1 has been pulled out becomes slightly troublesome.

[0016]

As is clear from the above description, according to the method for laying civil engineering nets of the present invention, when the civil engineering nets are pulled out to the surface of the water, the civil engineering nets may receive a large resistance to water or be below the water surface. Since it does not become entangled with the soft ground, it can be easily pulled out without breaking the civil engineering net, and there is a remarkable effect that workability is greatly improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a method for laying a civil engineering net according to the present invention.

FIG. 2 is a plan view showing a state where the civil engineering net of the embodiment is drawn out.

FIG. 3 is a partial perspective view of the net anti-sink device used in the embodiment.

FIG. 4 is a partial plan view showing another example of the net anti-sunken device.

FIG. 5 is an explanatory view showing a conventional method of laying a civil engineering net.

[Explanation of Signs] 1 Civil engineering net 3 Soft ground 4 Water surface 5 Net anti-sun set 5a

Claims (1)

(57) [Claims] 1. A civil engineering net according to claim 1, wherein the civil engineering net is superimposed on a net anti-sunken device formed by connecting a large number of floats and drawn out to the water surface on soft ground, and then the net anti-sun net is removed. Laying method.