JPS60340Y2 - Sand control material - Google Patents

Description

[Detailed description of the invention] This invention relates to a sand control material mainly used in reclaimed seawall construction work involving large-scale concrete, such as caisson breakwaters and single-block concrete breakwaters.

In recent years, the importance of land reclamation projects has become increasingly important in Japan, which has a limited amount of land.

Particularly in Japan, where the topography is steep and there is little flat land, securing the development of industrial, port, and residential land through reclamation work in coastal areas has become an important national project.

Conventionally, in the construction of seawalls and breakwaters for these reclamation works, caisson breakwaters, single concrete block breakwaters, or firewalls were constructed by placing large caissons, large single blocks of concrete, or extra-large blocks, etc. side by side on the lower rubble layer. Construction of large concrete block type embankments, such as what is called a wave-type vertical revetment, is being carried out.

However, in the above-mentioned breakwater seawall construction, when super-large concrete structures such as caissons and single concrete blocks are installed side by side, it is extremely difficult to bring the adjacent parts of the structures into close contact with each other, and there is a gap between the two structures. A gap of 10 to 15 cm is unavoidable, so conventionally, vertical grooves are provided on the corresponding surfaces of the adjacent gaps, and a compat is inserted inside the groove to seal the gap. Construction work was carried out to prevent soil from being washed away into the ocean.

However, if each adjacent area is made completely impermeable in this way, seawater that has entered the soil on the reclaimed land when the tide changes from low tide to high tide will pass through the seabed under the embankment and reach the ocean side when the tide goes low. At the same time, the troublesome problem of soil being washed away from the landfill side began to be raised.

For this reason, it is said that it is better to cover the gap between the two partnerships with a sand-prevention material such as a water-permeable net or cloth on the inside of the landfill side so that water can drain through the sand-prevention material.

However, when the tide changes from high tide to low tide, the water level drops faster on the ocean side than on the reclaimed side, creating a water level difference between the two.
Water is discharged from the landfill side to the ocean side with considerable pressure through the gap between the ties, and a thin anti-sand cloth sheet of about 1 to 2 m1 would be torn by the water pressure.

For this reason, a sandproof cloth sheet is sometimes covered and reinforced with an impermeable sheet such as a rubber sheet with many drainage holes, but this has poor drainage and is thin, so it does not have sufficient sandproofing properties. I couldn't hope for it.

Furthermore, it is also possible to use a thick mat-like sheet in which fibers are mechanically entangled, but this mat-like sheet alone has weak structural strength compared to woven fabric, so there is a risk of hair removal due to water pressure. Therefore, it was unsuitable for this type of sand control material.

In view of the above, this invention provides a sand prevention material as described below to solve the conventional drawbacks and problems.

To explain the drawing implementation of the sand control material of this invention, the third
, 4, 1 is approximately 1 m with thin reinforcement material 2a having a diameter of approximately 1 m/m.
The net body 2 in which a fine mesh of /m is formed is 5 of the fine reinforcement material 2a.
~ Appropriate elongation rate (approximately 30
This is a plastic net made of plastic material with 0%).

As the above-mentioned plastic material, polyethylene mixed with black carbon to improve its weather resistance is used.

4 is a mat-like sheet made of synthetic fibers entangled by mechanical processing such as needle punching, and is preferably as thick as possible.

Therefore, the anti-sand material of this invention is made by disposing the plastic net 1 on both the front and back surfaces of the thick mat-like sheet 4, covering them, and combining them with the fixing fittings 5.

The sand control material A of this invention is constructed as described above.
As shown in Drawings 1, 2, and 4, caissons, single concrete blocks, etc. are installed in parallel on the rubble layer 7.
It is used by fixing concrete nails 11 to the inner surfaces of the adjacent joints 6 and 6, respectively, so as to close the gap 10 between them with the inner surface of the landfill side 8.

Note that 9 in the figure is the ocean side.

As described above, when the sand prevention material A of this invention is used, only the water on the reclaimed side 8 passes through the sand prevention material A and is drained to the ocean side 9 through the gap 10, and the earth and sand on the reclaimed side 8 is washed away by the sand prevention material A. Secrets are prevented.

The anti-sand material of this invention is made of a thick mat-like sheet 4 made of synthetic fibers mechanically intertwined with each other, with plastic nets 1 placed on both the front and back sides of the sheet to cover and integrate the inside. The mat-like sheet 4 is very thick at 20 to 3 Qm/m, and its front and back surfaces are covered with a plastic net 1 for reinforcement and protection. This is completely different from the case where the water on the landfill side 8 passes through the cloth sand prevention sheet 12 and is adversely affected by the sudden drop in the water level, causing the sheet to break in a short period of time. In such a case, as shown in Figure 5 of the drawing, the water level from the landfill side 8 gradually decreases along a parabolic line, and no excessive pressure is constantly applied to the mat-like sheet 4 of the anti-sand material A, causing it to break or bend over a long period of time. It has an excellent effect in that it can perform a stable function of preventing sediment runoff without causing any phenomena.

Furthermore, when drainage is carried out through the sand prevention material A, the strong water pressure exerts a shearing force on the mat sheet 4 that tends to break it at the corner of the concrete 6, and the shearing surface must resist this force. This is greatly influenced by the degree of convergence of the fibers, but since the sand control material A of this invention uses a mat-like sheet 4 with a thickness of 20 to 30 cm, it is highly resistant to the shearing force and frictional force mentioned above. It is strong, stable, and can withstand long-term use, and since both the front and back sides of the mat sheet 4 are covered and combined with plastic nets 1, entangled fibers will not be peeled off by water pressure and hair loss will not occur. There are effects such as

Furthermore, even if the plastic net itself has a simple flat net structure of the same thickness, it has a weak shear strength even if it has tensile strength, and has the disadvantage that it is particularly susceptible to bias shearing and tearing. The plastic net 1 is a thin reinforcement material 2a, and the fine mesh net body 2 is the thin reinforcement material 2a.
It has a structure that is integrally reinforced with lattice reinforcing bars 3 made of reinforcing bars 3a that are several times thicker than the above, in other words, it has a composite net structure made of reinforcing bars of different thicknesses and has an appropriate elongation rate, so it has a high shear resistance. This plastic net 1 has the advantage of being strong against tensile and bending vectors in any direction and eliminating the disadvantage of being easily broken in the bias direction.
Since the mat-like sheet 4 is encased and combined, the mat-like sheet 4 is stably encased and protected, and its soil outflow prevention function does not deteriorate over a long period of time, and the plastic net 1 itself also functions as a soil outflow prevention function. It has outstanding effects such as

Furthermore, since the above-mentioned plastic net 1 has an appropriate elongation rate, the plastic net 1 of the anti-sand protection material A fixed to the concrete tie 6 will be distorted in its curved shape even if the tie 6 is tilted and the fixed point distance is extended. It has the effect of being able to be covered by the material and not being broken or separated.

[Brief explanation of the drawing]

The drawings show an embodiment of the sand control material of this invention. Figure 1 is a longitudinal cross-sectional view of the sand prevention material installed on an embankment body, Figure 2 is a cross-sectional plan view of the same, and Figure 3 is a diagram of the sand prevention material. Enlarged perspective view of main parts,
FIG. 4 is an enlarged cross-sectional plan view of the same installed state, FIG. 5 is an explanatory diagram of the same water level falling state, and FIG. 6 is an explanatory diagram of the water level falling state in the case of the conventional sand control sheet. 1...Plastic net, 2...Curved body, 2
a... Thin reinforcement material, 3... Lattice reinforcing bar
3a...Thick reinforcement material, 4...Mat sheet, 5...Fixing metal fittings, 6...Partnership, 7
...Rubble layer, 8 ... Landfill side, 9 ... Curved ocean side, 10 ... Gap, 11 ... Concrete nail, 12 ...・・Canvas-like sand control sheet, A・
... Sand prevention material.

Claims (1)

[Scope of utility model registration request] A plastic net 1 having an appropriate elongation rate, which is integrally reinforced with lattice-shaped reinforcing bars 3 made of fine reinforcements 2a and thick reinforcements 3a several times or more thicker than the above-mentioned fine reinforcements 2a, is synthesized. This anti-sand material is made by covering and combining a thick mat-like sheet 4, which is mechanically entangled with fibers, arranged on both the front and back sides respectively.