JP2001098525A - Sandy beach erosion protection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sandy beach erosion protection method which can recondition a sterile sandy beach to a sandy beach rich in sand as before and can prevent sand in a sandy beach in nature from being let flow to cause erosion of the sandy beach rationally and surely without impairing the spectacle of nature. SOLUTION: In a sandy beach in nature, heavy artificial sand 2 artificially manufactured by crushing rock with a specific gravity of 2.9 or more and ores is stacked thick on general sand 4 with a specific gravity of about 2.6 of a sandy beach in nature, or on the partially exposed ground where such sand is lost by erosion, or coated thereon with a desired thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sand beach erosion protection method mainly used for restoring a sandy beach which has been eroded on a coastal area to a large extent and for preventing the sandy beach from being eroded again and becoming thinner. It is about.

[0002]

2. Description of the Related Art In recent years, natural sand beaches have been eroded due to a decrease in the amount of outflow of sand from rivers and changes in coastal tides, and the number of thin sand beaches whose sand has rapidly decreased has been increasing. In order to improve such a sandy beach, for example, sand transported from another place was piled up thickly on a thin sandy beach on the shore, and artificially restored to its original rich sandy beach (nourishment) Even if it is a place where not only sand has once been washed away but also sand is easily washed out from the beginning,
Thick piles of sand are likely to be washed away again, and the same will be repeated many times.

[0003] For this reason, in order to prevent sand loss, it is necessary to construct a jetty to control the direction of the tidal current and to control the tidal current offshore to prevent sand loss. It has been installed to make it less susceptible to the effects of waves and to make it easier for sand to adhere to the coast. In addition, a concrete block is provided directly on a sandy beach in a coastal area, and the sand is covered with the concrete block.

[0004]

However, such a jetty, a breakwater or a concrete block as described above has a problem that the natural scenery is significantly impaired. Recently, in order to prevent the natural scenery from being damaged, a method of stabilizing the sandy beach by embedding pipes in the sandy beach and improving the drainage property to reduce the buoyancy of the sand particles and thereby stabilize the sandy beach has been proposed. (JP-A-9-88034, JP-A-9-88034)
-88035).

[0005] However, when burying pipes in the coastal area including the underwater area, the actual construction work is difficult because of the fact that the surrounding sand is liable to collapse due to waves even when excavating and forming grooves. There is a problem that it is often difficult.

[0006] In view of the above problems, the present invention can restore a thin sandy beach to a sandy beach where the sand is rich, and at the same time, rational and surely maintain the natural scenery without impairing the natural scenery. It is an object of the present invention to provide a sand beach erosion protection method capable of preventing the sand of a sand beach from being washed away and eroding the sand beach.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the sand erosion protection method of the present invention is applied to a natural sand having a specific gravity of about 2.6 on ordinary sand or such sand. On the partially exposed ground that has been eroded and lost, crushes rocks and ores with a specific gravity of 2.9 or more, and artificially manufactures heavy artificial sand. It is characterized by being coated.

According to such a sand beach erosion protection method, the natural sand has a specific gravity of about 2.6, or the ground which is partially eroded by the erosion of such sand. On top of this, heavy artificial sand produced by crushing rocks and ores having a specific gravity of 2.9 or more is piled up thickly, or covered with a desired thickness to restore the sandy beach to its original form. Can be restored to a rich sandy beach, and heavy artificial sand is less likely to be washed away by waves than ordinary sand,
Erosion of the sand beach can be reasonably and reliably prevented. In addition, since the heavy artificial sand has the same appearance as natural sand, it is possible to prevent the natural scenery from being damaged.

[0009]

Embodiments of the present invention will be specifically described below with reference to the drawings. 1 and 2
FIG. 1 is a diagram referred to for describing a first embodiment of a sand beach erosion protection method according to the present invention.

FIG. 1 is a sectional view showing a sandy beach after being constructed by using the sandy beach erosion protection method according to the first embodiment of the present invention. The artificial sand 2 in contact with the sea surface of the seawater 1 shown in FIG. 1 is rich in sand on the thin natural sand 4 (or exposed ground) as shown in FIG. The beach is nourished and piled up like a sandy beach.

That is, natural sand 4 shown in FIG.
The sand is completely eroded by the waves, but the artificial sand 2 is piled up thickly on the natural sand 4 as shown in FIG. The street sand has been restored to a rich sandy beach.

The specific gravity of the natural sand 4 is usually about 2.6 on average. More specifically, considering that the composition of natural sand 4 is divided into heavy particles having a specific gravity of more than 2.75 and light particles having a specific gravity of less than 2.75, about 80% of the light particles have a specific gravity of less than 2.75. It is said to be occupied by.

On the other hand, the artificial sand 2 is composed of heavy particles having a specific gravity of 2.9 or more. Such artificial sand 2 has a specific gravity of 2.9 to 3.2 produced from the natural world.
Heavy particles such as peridotite, diorite and serpentine. In addition, heavy particles of ores such as magnetite, hematite, and iron sand having a specific gravity of 4.0 to 5.3 are also included.

The artificial sand 2 is obtained by crushing such high specific gravity stones and ores to artificially produce sand of heavy particles having a large specific gravity. As a specific production method, the high specific gravity stone or ore can be crushed by a sand maker such as a crusher or a rod mill so as to obtain a particle size equivalent to that of sand.

Since the artificial sand 2 thus artificially produced is produced using high specific gravity stones and ores as raw materials, each of the particles also becomes a heavy particle having a high specific gravity. Unlike a natural sand 4 composed of light particles having a low specific gravity, the sand is not easily eroded by the movement of the seawater waves and does not erode the sandy beach.

For this reason, the artificial sand 2 thus artificially produced is thickly stacked on the natural sand 4 as shown in FIG. The sand can be restored to a sandy beach with abundant street sand, and the heavy artificial sand 2 is harder to be washed away by waves than ordinary sand, so that the sandy beach can be rationally and reliably prevented from being eroded. . In addition, since the heavy artificial sand 2 does not look different from natural sand, it is possible to prevent the natural landscape from being significantly impaired.

Since the artificial sand 2 can be handled in the same manner as ordinary sand, no special machine or construction method is required.
Heavy sand artificially manufactured from peridotite or diabase rock can be easily distinguished from ordinary sand because of its green color. Therefore, the state of the change can be easily measured even when controlling the thickness at the time of construction and observing the progress after the construction, so that there is a feature that it is easy to determine the presence or absence of the loss.

In the sand beach erosion protection method according to the present invention,
Since the sand particles themselves are used for nourishment (covering sand) using the heavy artificial sand 2 having a large specific gravity, there is an advantage that the construction is easy.

As a method of thickly accumulating the artificial sand 2 on the sandy beach of the natural sand 4 and raising the beach, there are both a method of thickly accumulating the artificial sand 2 from the land and a method of thickly accumulating the artificial sand 2 from the sea. Conceivable. When the artificial sand 2 is piled up thickly from the land, the artificial sand 2 is generally transported to a place near the construction site using a dump truck, and the height and thickness are taken into consideration by a construction machine such as a bulldozer or a backhoe. While spraying or unwinding in a predetermined area.

The artificial sand 2 is placed on the sandy beach of natural sand 4 from above the sea.
In the method of stacking thickly, artificial sand 2 loaded on a crane barge or barge, etc., is towed near the shoreline and thrown into a predetermined area with a crane bucket, or near the shore by a work boat such as a barge unloader ship. To

FIG. 3 is a cross-sectional view showing a sandy beach after construction using the sandy beach erosion protection method according to the second embodiment of the present invention. In the first embodiment, the artificial sand 2 is directly thickly piled on the natural sand 4.
In the embodiment of the present invention, as shown in FIG. 4, first, ordinary sand 3 having a specific gravity of about 2.6, which has been transported from another place, is thickly piled on natural sand 4 and nourished. As shown in (1), the artificial sand 2 is covered with the artificial sand 2 (covering sand).

Since the artificial sand 2 is expensive, the cost for the construction can be reduced by sandwiching the inexpensive ordinary sand 3 between the artificial sand 2 and the natural sand 4. The sand particles repeatedly move to the land side and the offshore little by little by the waves, but the thickness of the high specific gravity artificial sand 2 is reduced to such an extent that the ordinary sand 3 inside the artificial sand 2 is not exposed to the surface by such movement. You only need to secure it.

In the above embodiment, the artificial sand 2
Used artificial sand (first artificial sand) produced by crushing high-density stones and ores. Fine particles having a smaller diameter than the sand produced during the production of the first artificial sand were removed using polymer cement mortar or resin. The second artificial sand can be used as the artificial sand 2 by adhering and granulating with a system binder or the like and having the same size as the sand particles (second artificial sand).
A mixture of artificial sand can be used as artificial sand 2.

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various other modifications may be made based on the technical concept of the present invention. Can be changed.

[0025]

As described above, according to the sand beach erosion protection method of the present invention, natural sand has a specific gravity of about 2.6 on ordinary sand or such sand is eroded. Heavy artificial sand made by crushing rocks and ores having a specific gravity of 2.9 or more is piled up thickly on the partially exposed ground, or covered with a desired thickness. In addition to being able to restore a thin sandy beach to a rich sandy beach, heavy artificial sand is less likely to be washed away by waves than ordinary sand, so it is reasonable and reliable to ensure that the sandy beach is eroded. Can be prevented.

In addition, since the heavy artificial sand has the same appearance as natural sand, it is possible to prevent the natural landscape from being damaged.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a sand beach constructed using a sand beach erosion protection method according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing natural sand 4 eroded by waves before artificial sand 2 is piled up thickly.

FIG. 3 is a cross-sectional view illustrating a sand beach constructed by using a sand beach erosion protection method according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a sandy beach in which ordinary sand 3 is thickly stacked on natural sand 4 as an intermediate construction procedure before coating with artificial sand 2 in FIG.

[Explanation of symbols]

 1 Seawater 2 Artificial sand 3 Normal sand 4 Natural sand

Claims (5)

[Claims] 1. A natural beach having a specific gravity of 2.9 on ordinary sand having a specific gravity of around 2.6, or on a partially exposed ground which has been eroded away by such sand. Over rocks,
A sandy beach erosion protection method characterized in that heavy artificial sand produced artificially by crushing ores is piled up thickly or covered with a desired thickness. 2. The specific gravity of natural sand beaches is about 2.9 on ordinary sand, or on the ground partially eroded by the erosion of such sand, and has a specific gravity of 2.9. Over rocks,
Sandy beach erosion protection characterized in that heavy artificial sand produced by granulating by bonding fine particles formed by crushing ores with a binder is thickly stacked or covered with a desired thickness Construction method. 3. On a natural sand having a specific gravity of around 2.6, or on a partly exposed ground where such sand is eroded and lost, the specific gravity is 2.9. Over rocks,
A first artificial sand artificially produced by crushing ores, a rock having a specific gravity of 2.9 or more, and fine particles produced by crushing ores are bonded with a binder to form a first artificial sand. (2) A sand beach erosion protection method, wherein a mixture of two artificial sands is piled up thickly or covered with a desired thickness. 4. Transport from another location on natural sand with a specific gravity of natural sand beach of around 2.6, or on the ground partially exposed due to erosion of such sand. The ordinary sand that has been piled up thickly, and on this ordinary sand, a heavy artificial sand made by crushing rocks and ores with a specific gravity of 2.9 or more and artificially produced to a desired thickness. Beach erosion protection method characterized by the following. 5. Transport from another location on natural sand with a specific gravity of natural sand beach of around 2.6, or on the ground partially exposed due to the erosion of such sand. The ordinary sand that has been piled up thickly, and on this ordinary sand, the first artificial sand artificially manufactured by crushing rocks and ores having a specific gravity of 2.9 or more, and a specific gravity of 2.9 or more It is characterized in that a mixture of fine particles formed by crushing rocks and ores and a second artificial sand manufactured by granulating by bonding with a binder is coated with a desired thickness. Sand beach erosion protection method.