JPH086341B2 - Rubble mound protection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to various types of coastal and undersea structures such as breakwaters and seawalls, in which rubble stones are attached to the main body or foundation of the structure. When used, it relates to a construction method for protecting the outer surface of the rubble mound.

(Prior Art) Generally, rubble stones have been used for structures of this type since ancient times, regardless of size. The reason is
Due to structural reasons such as preventing the concentration of stress in the upper structure by supporting the upper structure with a soft structure, such as adjusting the ground level at the base, and the specific gravity in the sea It is considered to be based on the reason that the use of stone is optimal for economic reasons as a material that is large, robust, and durable, and can be obtained in large quantities at low cost.

However, as a recent trend, the above structures are often installed in deep water positions as the scale of economic activity increases, and in order to protect the base and rubble mound from the waves, The various construction methods have been compared and examined, and not the uniform construction method, but the construction method that seems to be most suitable according to various conditions such as location and purpose of use is adopted.

By the way, some examples of the main construction methods are as follows: a method of using a covering stone whose weight per piece is significantly larger than a rubble stone, and a large covering stone is difficult to obtain in a large-scale structural part. Therefore, by designing and using each block for the purpose of solidifying, covering, and wave-dissipating by means of increasing the weight per concrete block, or by adding auxiliary means using various materials to these Methods such as protecting the rubble mound are applied.

On the other hand, apart from this, baskets typified by gabions are well-known materials that have been widely used mainly for temporary equipment in river construction and coastal construction since the past. Since it is a basket made of braided bamboo or iron wire, it cannot avoid the fatal weakness of poor durability, so it was never applied to this equipment, let alone large-scale structures.

(Problems to be solved by the invention) From the technical background as described above, the method of protecting rubble mounds in large-scale structures is currently mainly made of concrete blocks. But,
This has the following problems.

B) First, as the scale of the construction structure increases, the weight required for each concrete block tends to increase, and it is not possible to make the size of the block as large as possible, considering the common sense of the design. There is.

B) In other words, the enormous size of the block will cause an excessive load per unit area on the rubble mound itself, and this will be added to the impact load of the waves, resulting in a problem with the stability of the rubble mound itself. There is a fear.

C) There have been many cases of damage caused by large waves,
It is extremely difficult to restore and repair it, and the construction cost becomes very expensive.

D) Less resistance to erosion at the base of the tip of rubble mound.

E) Large-scale construction machines and work vessels are required for production and installation, which is economically disadvantageous and also anxious in terms of occupational safety.

F) It is difficult to flexibly deal with the stability of the rubble mound coating against waves during construction and during construction interruption.

The above is a list of problems related to consolidation blocks and covered blocks for large-scale mixed dikes.
The wave-dissipating block is a construction method that is inevitably adopted when it is not possible to deal with the above-mentioned blocks by design, which is economically extremely disadvantageous.

The rubble mound protection method according to the present invention was developed to address the above-mentioned problems, and has been used as a rubble mound protection method applied to the main body or foundation of large-scale structures on the coast and in the sea. Pays attention to the excellent characteristics of gabions that could not be considered at all in the conventional technical common sense, and reconstructs the construction method from the point of view of the structure and effect of the protective member and newly reconstructs it. It succeeded in solving all the problems at once.

[Structure of Invention]

(Means for Solving Problems) In the method of protecting a rubble mound according to the present invention, in order to achieve the above-mentioned object, a polymer material or a metal material excellent in corrosion resistance, wear resistance and impact resistance and having a large tensile strength is prescribed. As a protective member, the cage that keeps the shape of forming a mesh is filled with stone and sealed as a protective member, and by connecting a plurality of the protective members with a binding member to integrate them, It is characterized in that a part or the whole of the outer surface including the basal plane is covered.

(Examples) Hereinafter, an embodiment of the method of the present invention will be specifically described with reference to the drawings. Fig. 1 shows an example in which the present invention is applied to a hybrid breakwater, and Figs. 2 to 4 show the present invention. It is an example of the structure of the protective member used in the construction of the invention method.

First, the protection member 2 used for covering the rubble mound 1
As for the above, it is difficult to unambiguously specify the shape and construction form because they differ greatly depending on the standard cross section of the structure body 3 to be constructed, the construction purpose, etc. A cage N that is the main body, a stone material S such as rubble or quarts that is filled and sealed inside the cage N, and a plurality of single gabion or futon cages depending on the form of use. It is configured by a combination with a binding member W such as a rope that is connected and integrated in various shapes.

Among them, in the case of the present invention, as the material of the cage N which is the main body of the protection member 2, corrosion resistance, abrasion resistance and impact resistance are used without using a cage woven with bamboo or iron wire as in the conventional case. A polymer material having excellent mesh strength and high tensile strength, which is formed into a predetermined mesh shape, or a stainless steel wire which is an alternative to the above and is formed into a cage by braiding is used. Examples of the former are the product names “PARASTRIP”, “PARATIE”, and “PAR” manufactured by ICI in the UK.
There are "AGRID" and "PARALINK", 3-3 Yushima, Bunkyo-ku, Tokyo
9-10 Product name “Tensor” released by Mitsui Ishikasan Co., Ltd.
Is also suitable. Further, as the latter example, gabions using stainless steel made by Nippon Gold & Steel Co., Ltd., 2-10-6 Sotokanda, Chiyoda-ku, Tokyo, can be used, but these are typical commercially available products. However, the present invention is not necessarily limited to the above products, and other products can be sufficiently used according to the construction purpose as long as they have the above physical properties.

On the other hand, in the case where the cage N is filled with stone materials S such as rubble and crushed stones and sealed, as shown in Fig. 2 (a) and (b), the gabion 2a and the futon cage 2b are separated. In addition to being used as it is as the protective member 2 in a state, a plurality of gabions 2a and futon baskets
2b are connected to each other in a vertical direction or a horizontal direction and a vertical direction, a horizontal direction, and an upward direction by a binding member W such as a rope, and as shown in FIG. 3 (a) and (b), the planar bodies 2c, 2d or FIG. 4 (a) ( B) like a lump 2e,
In some cases, the member formed in 2f may be used as the protective member 2.

FIG. 1 shows an example of a hybrid breakwater constructed by using the above-mentioned protection member 2. In the case of this embodiment, first, the gabion surface is formed on the tip of the base mound before the rubble stone 1a is loaded. After laying the bodies 2c or 2d as the first protective member 12, the gabion 2a for stopping the front end is laid as the second protective member 22 in parallel with the extending direction of the breakwater to improve the visibility of the tip of the rubble stone method. Then
It is tightly connected to the first protection member 12. Then, the rubble stone 1a is sequentially inserted between the second protective members 222, 22 to form the rubble stone mound 1 having a trapezoidal cross section as in the conventional method, and after performing a simple leveling operation, the rubble stone mound 1 is removed. The gabion sheet 2c is laid on the outer surface as the third protection member 32 to cover the outer surface of the rubble mound 1. Finally, at the time of the caisson 10 which is the main structure of the breakwater, the gabion surface bodies 2c, 2d or the gabion lump bodies 2e, 2f are mounted as the fourth protection member 42 which plays a role of a root block if necessary. Then, a desired number of steps are stacked and tightly connected to the third protection member 32 below. When caisson is used, careful construction is required, including consideration for anchoring from inside the rubble mound 1.

The standard cross-sectional view of the hybrid breakwater shown in FIG. 1 is based on a design method that takes into consideration the conventional method of protecting rubble mounds. If the standard cross section shown in FIG. 5 is used, the caisson 10 can be theoretically reduced in size, and a more economical design can be performed.

The above-mentioned embodiment is one in which the method of the present invention is applied to the construction of a hybrid breakwater, but the method of protecting a rubble mound according to the present invention is not limited only to the above-mentioned example,
It can be freely applied to other breakwaters and breakwaters, for example embankments with rubble mounds only. In addition, when damage or partial movement occurs in the construction method using concrete blocks such as existing breakwaters, in order to prevent the damage from spreading due to the dumping and scattering of rubble and to prevent the movement of blocks, the construction method of the present invention is applied, and The gap between the blocks may be filled with a gabion, and the two may be tightly connected and reinforced with a rope or the like. In addition to this, the method of the present invention can be freely adapted to the conditions of the embankment and the repair place.

〔The invention's effect〕

As described above, according to the construction method of the present invention, the stone material filled inside the basket has a larger specific gravity than concrete, and the difference in specific gravity in the sea becomes even more remarkable, and the cage for holding this Is well-suited to the base ground and rubble mound or existing concrete blocks, and
The friction coefficient is remarkably large, and because it has excellent water permeability, it has characteristics that can adapt to the jet phenomenon from the rubble mound, and the gabion attached to the base part is resistant to erosion of the tip part. Since it also has a function of generating a suppression effect due to self-weight subsidence, etc., the synergistic effects of these exert the following use effects.

B) Even if the volume of the stone material filled in the cage is small, a large number of cages are connected and integrated to form a single unconnected piece that is used as a conventional method. The result is that a small basket volume, that is, a small amount of stone material, can protect the surface area of a large rubble mound.

Currently, the use of concrete blocks is the mainstream because it is difficult to obtain huge block-shaped covering stones in the inventory. From this, it is possible to connect individual solids even if compared to obtain the same protection performance as the block based on the design technical standards.Because the thickness of the protective member can be made thin, the installation top water depth on the mound can be reduced. Becomes deeper,
The impact of water pressure on the waves is reduced, and the overload of the protective member on the mound is reduced, so the stability of the mound itself is increased. Make it cheap and increase stability. In addition, stone saving can be expected to have a secondary effect of reducing general environmental damage due to stone extraction such as quarrying mountains.

B) Since the shape and size of a unit of protective member filled with a stone that retains its shape is fixed, it is possible to design and construct the protective member in relation to the area to be covered. Yes,
Also, by adjusting the amount of stone material packed in a cage that maintains its shape (such as adjusting the particle size of the stone material), it is possible to adapt to the jet phenomenon from the rubble mound and design a porosity suitable for absorbing shock wave pressure. There is also. In addition, since each protective member is reasonably flexible as a characteristic of using a cage that retains its shape, it has the function of absorbing shock due to waves, and softly receives shock wave pressure with viscoelasticity. Can soften the shock.

In other words, the seawater present in the void between the rubbles of the mound oscillates and jets out due to the large waves (up and down movement of the water surface) that strikes the front of the breakwater or seawall. One of the conditions for stabilizing the protective member is how quickly the pressure difference between the upper end and the lower end is eliminated. The artificial block has water holes that penetrate the upper and lower ends (not in natural stone covering stones), but due to the strength of the block itself, a large number of holes cannot be provided. The filled stone is porous and has suitable voids to absorb shock wave pressure. In addition, since the net-like bag filled with stone material has an irregular shape, it is deformed against the lateral moving pressure and has no resistance, and even if a non-uniform force due to waves acts on it, even if it is tied vertically and horizontally with an auxiliary rope. , Floating, slight lateral movement and rope extension are repeated due to waves, and the mesh nets adjacent to each other are caught or run up, exposing the surface of the rubble mound. Therefore, in the conventional underwater foundation construction method using a net-like bag, it is necessary to cast and fix the underwater concrete to the aggregate of the net-like bags filled with stones. On the other hand, the cage-based protection member of the present application can appropriately cope with the jet flow phenomenon as described above, and is moderately rigid and flexible (flexible) in common so that it is viscoelastic, so that the impact due to waves is softened. Receiving and softening the impact, reducing the impact load on the mound, and being familiar with the unevenness of the rubble mound, and having a significantly large frictional resistance coefficient, it becomes possible to maintain a stable state on the rubble mound. There is no need to perform the placing work with underwater concrete as in the conventional method.

C) The weight of one unit of protective material is much lighter than that of concrete blocks, so construction workability is good and there is no concern in terms of occupational safety.

D) It has a very good compatibility with the rubble mound during and after construction, and has excellent stability against wave impact and erosion of the ground foundation.

E) Although it is used as this equipment, even if it is used as temporary equipment, the same construction method can be adopted, and emergency measures and repair work can be easily dealt with.

F) If no special wave-dissipating purpose is required, it is possible to expect a sufficient coating stabilization effect for almost all rubble mounds of any size.

As described above, the construction method of the present invention is a conventional construction method in all respects such as structure, hydraulic stability, workability, occupational safety, emergency response, economic efficiency, and conservation of the marine environment. Is far superior to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an implementation structure of a hybrid breakwater constructed by applying the method of the present invention, FIG. 2 (a) (b), FIG. 3 (a) (b) and FIG. 4 ( B) is a perspective view showing a protective member used in the method of the present invention, and FIG. 5 is a sectional view showing another typical embodiment of the present invention. 1 …… Rubble mound, 1a …… Rubble, 2 …… Protective member, 2a
…… Gabion, 2b …… Futon basket, 2c, 2d …… planar, 2e, 2f …… lump, N …… basket, S …… stone, W …… bonding member, 10 …… caisson, 12 ...... First protection member, 22 ...... Second protection member, 32 ...... Third protection member, 42 ...... Fourth protection member

Claims (1)

[Claims] 1. A stone material is filled inside a cage which is formed of a polymer material or a metal material having excellent corrosion resistance, abrasion resistance and impact resistance and high tensile strength so as to form a predetermined mesh, and is sealed. Of the rubble mound characterized by covering a part or all of the outer surface including the basal surface of the rubble mound by connecting a plurality of the above-mentioned protection members with a binding member and integrating them Protective construction method.