JPH0376368B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to asphalt pine used to protect the foundations of underwater structures etc. from scouring, and particularly relates to asphalt pine that has water permeability in the peripheral area of the pine. The present invention relates to an asphalt mat in which a heavy member is integrally attached, and its ends are prevented from being stirred up by water currents or waves.

(Conventional technology) Conventionally, when constructing underwater structures such as breakwaters and offshore work platforms, a foundation rubble layer is formed on the seabed ground, and the top layer is leveled and then leveled. ,
I am trying to construct the structure itself.

If the seabed is sandy or has a relatively small gravel layer, the seabed is leveled and then covered with canvas, vinyl chloride boards, or asphalt pine formed to a specified thickness. In most cases, the foundation is laid by laying foundation rubble, etc. on top of it, and then the structure itself is built on top of that foundation.

Among the above-mentioned materials, asphalt pine in particular is often used for the foundations of underwater structures in sea areas with relatively rough waves or in places with fast ocean currents. prevention,
It is used for purposes such as preventing sand, etc. from being sucked out from the ground.

As for the above-mentioned asphalt pine, the present applicant has previously disclosed the
As described in Publication No. 45284, Japanese Patent Publication No. 50-17623, etc., a reinforcing member such as a glass fiber net and a wire rope for lifting are sandwiched between asphalt mastic in a sandwich-like manner. It is formed in one piece.

However, when asphalt pine as described above is used to construct an underwater structure, it may be affected by the structure and generate eddy currents around it. In particular, if the seabed ground where the structure is constructed is sandy or a relatively small gravel layer, the ground at the tip of the asphalt pine will be scoured by the above-mentioned eddies and waves, etc. As a result, the tip of the asphalt pine may curl up or become agitated by eddies or waves, resulting in a situation where the base cannot be reliably supported.

Therefore, if the foundation of an underwater structure continues to be scoured under such conditions, the supporting capacity of the foundation will decrease, and the structure will gradually tilt, or if it is affected by large waves from a typhoon, etc. Undersea structures become unstable, and in severe cases, accidents such as overturning occur.

Therefore, in order to prevent the above-mentioned scouring of the foundation, the applicant first formed a number of holes in a predetermined area at the end of the asphalt pine and sucked out the sand from the ground through the holes. proposed that the tip of the asphalt pine be bent into the sand or the like in the ground in a natural state to reduce the influence of subsequent waves on the asphalt pine. (Japanese Patent Application No. 59-189621) (Japanese Unexamined Patent Publication No. 61-68914) However, although the asphalt pine of the above-mentioned earlier application is used to support the foundations of underwater structures in areas with relatively rough waves, As a premise,
The condition is that there will be periods of relatively calm waves during the construction period and for a specified period after the completion of construction, and gentle scouring will be carried out during those periods of calm waves. The tip of the asphalt pine is bent in a natural manner, and the purpose of this bending is to prevent scouring during subsequent periods of rough waves.

However, when the construction period is limited and construction is required to be carried out during periods of rough waves, or when constructing an underwater structure in a place with fast water currents, etc.
When construction is carried out in areas with poor construction conditions, the surrounding area will be subject to scouring immediately after the asphalt pine is laid, and the above-mentioned pine with perforated ends will be susceptible to scouring by ocean currents. There are cases where it becomes impossible to deal with the situation.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned drawbacks of the conventional example. By installing asphalt pine, when the surrounding area is scoured, the asphalt pine immediately bends easily according to the seabed ground, thereby making it possible to cope with scour caused by ocean currents, etc. The purpose is to provide

(Means and effects for solving the problems) The asphalt mast of the present invention has a reinforcing member such as a glass fiber net inserted between the layers of asphalt mastic, and furthermore, a reinforcing member made of a glass fiber net or the like is inserted at a predetermined interval along the reinforcing member. Suspension members such as wire ropes are buried in the area.

Furthermore, the asphalt mast of the present invention is provided with a weight member formed of a chain or the like around the asphalt mast. This combination forms a weight member having approximately the same thickness as the asphalt mat main body.

The length of this weight member is determined according to the speed of the ocean current at the location where the asphalt pine is laid. If the ocean current is very fast, the protrusion length should be increased. .

Therefore, the asphalt pine of the present invention is
Even if it is affected by scouring by rough waves, etc. immediately after it is laid, the weight member, which is highly permeable to water and sand, is first buried in the seabed ground and acts as an anchor. , it becomes possible to reliably prevent the surrounding area of asphalt pine from being stirred up under the influence of ocean currents, waves, etc., or from being subjected to strong scouring.

(Example) The structure of the asphalt mat of the present invention will be explained according to the illustrated embodiment. As shown in FIGS. 1 and 2, the asphalt mat 1 of the present invention includes:
Its main body is similar to that of conventionally used asphalt masts, in which a reinforcing member 3 made of glass fiber net or the like is formed on a layer of asphalt mast 2 laid to a predetermined thickness. , wire ropes 5 are arranged at predetermined intervals,
Lifting eyes 6 are formed at both ends of the wire rope 5, and an anti-slip fitting 7 is provided in the middle of the eye.

In addition, a large number of iron bands 8 are arranged in a direction perpendicular to the wire rope 5 to add strength to the asphalt mat 1 in the longitudinal direction,
When a heavy object is placed on the asphalt pine, it can be supported reliably.Furthermore, the lower surface of the asphalt pine of the present invention is provided with reinforcing members depending on the installation location. may also form.

As shown in FIG. 3, the asphalt mat 1 of the present invention has a layer 10 of weight members formed by a large number of chains 11 around it. This layer of weight member 10 embeds the end of the chain 11 between layers of asphalt mastic,
It is formed by connecting multiple chains of a predetermined length using the links of the chain, and the thickness is approximately the same as the thickness of the asphalt pine body, and the length Usually
However, in the case of the asphalt pine according to the present invention, it is necessary to install the asphalt pine at the location where it is laid, depending on the roughness of the waves,
The speed of the ocean current is a major factor, especially in determining the width of the layer 10 of the weight member.

Next, according to the example shown in FIG. 4, the progress of scouring when the asphalt pine of the present invention is constructed will be explained. Immediately after constructing the structure, the asphalt pine 1
The construction is also carried out horizontally in line with the ground 12. However, due to the generation of eddy currents caused by the construction of the structure and the influence of water currents, a scour phenomenon occurs in the ground at the end of the asphalt pine 1, as shown in B.
A recess 13 is formed in the scoured ground 12.

However, in the asphalt pine 1 of the present invention, the weight member 10 is formed around it, and since the weight of the weight member 10 is very large, the recess formed by scour 13
The tip of the weight member 10 is bent to match the shape of the scoured ground.

Then, following the bending of the weight member 10 formed at the end of the asphalt mat 1, a phenomenon occurs in which the side part of the asphalt mat 1 bends as the scour progresses, as shown in FIG.

However, unlike in the case of rivers, the direction of the current in the sea differs depending on the time, and the phenomenon of scouring does not occur unilaterally. Therefore, after scour is performed by the ocean current in the direction of arrow V, backfilling is performed by the ocean current in the opposite direction.

Then, after a predetermined period of time has passed after the asphalt pine 1 of the present invention is constructed, the end of the asphalt pine 1 is inserted into the seabed ground 12 using the weight member 10 as an anchor, as shown in C. The asphalt mat 1 is buried, and a backfilling portion 13a is formed thereon, making it possible to maintain the surrounding area of the asphalt mat 1 in a stable state.
Since the asphalt pine 1 of the present invention is constructed as a support member for a foundation on the submarine ground 12 in the above-described state, the structure etc. constructed on the asphalt pine 1 is protected against rough waves and It will be able to safely support ocean currents and support its weight.

Since the asphalt mat 1 of the present invention has the above-described configuration, for example, the width, length, and thickness of the asphalt mat main body are determined in addition to conditions such as the size of the structure and its weight. It is divided and formed into predetermined shapes according to conditions such as ease of handling. When manufacturing the mat, a reinforcing member 3 made of glass fiber net is inserted into the middle of the mat, and wire ropes are arranged at regular intervals along the reinforcing member 3. The base end of a chain 11 of a predetermined length is buried in the surrounding area of the asphalt pine according to the invention, thereby forming a layer 10 of weights with a predetermined width.

In addition, an aluminum pipe or the like is fitted as a non-slip fitting 7 into a predetermined part of the wire rope 5, and it is crushed and attached to the wire rope 5 integrally, and washers are attached to both sides of the fitting. , wire rope 5
prevents it from slipping inside the asphalt mat 1.

The layer 10 of the weight member having a predetermined width is formed around the asphalt pine 1 as described above.
The end of the chain 11 of the layer 10 of the weight member is
As shown in Fig. 3, the asphalt mast 1 is buried in the asphalt mast 1, and the links of the chain 11 are connected from the part protruding to the side of the asphalt mast 1 to a thickness equal to the thickness of the asphalt mast body. For example, it can be formed to a thickness of 10 cm.

In the asphalt mast 1 of the present invention, the specific gravity of the asphalt mast is approximately 2.2, while the specific gravity of the chain 11 is approximately 7.8. is two to three times as heavy as the asphalt mastic alone, and furthermore, since the weight member 10 of the present invention has water permeability, it will not be stirred by water flow. There is nothing to do, and it will serve as an anchor.

In addition, the asphalt pine 1 of the present invention is intended to be installed in a place where the waves are relatively rough. It is possible to use the asphalt mat 1 of the present invention to support the foundations of underwater structures in locations with very poor conditions, such as those that are affected by rough waves before stabilizing. For construction work in places with extremely poor conditions like this, if the conventionally used asphalt pine is used alone, the results of hydraulic experiments indicate that it is necessary to use asphalt pine with a thickness of 30 to 50 cm. It turns out that.

However, even if thick asphalt pine as described above could be produced theoretically, it would be very heavy, difficult to transport and install, and the construction cost of the structure would be a huge problem. However, in the asphalt mat with a weight member attached to the end of the present invention, the thickness of the asphalt mat is made relatively thin like the asphalt mat used conventionally, By making the surrounding area heavier, the weight of the structure can be reliably supported by the ground.

In addition, in the above-described embodiment of the present invention, the chain 1 attached to the end of the asphalt mat 1
As for 1, other members can be used as long as they have a similar weight and flexibility structure as a chain, and water permeability, etc. Furthermore, the method of fixing to the asphalt mat can be arbitrary. Of course, it is also possible to adopt this method.

The asphalt mat of the present invention not only has a weight member attached to its end as described above, but also has a perforated material having a large number of holes 15 formed on the side of its main body, as shown in FIG. It is also possible to form a perforated asphalt mat by providing a section and integrally providing the weight member 10 at the end thereof.

In this case, the distribution of water, sand, etc. in both the weight member and the perforated part ensures the stability of the asphalt pine and its bending into the seabed ground in a very stable state. Even if the asphalt pine is affected by very fast eddy currents or tidal currents immediately after construction, the edges of the asphalt pine will not be stirred up or rolled up, and it will remain in contact with the seabed ground. This allows the asphalt mats to be integrated at an early stage, making it possible to securely support the structure.

In addition, the asphalt pine of the present invention can be used as a support member for the foundations of ordinary breakwaters and underwater structures, in the same way as conventionally used asphalt pine. By making it heavier, it is very easy to protect the foundation from scouring, etc., and the period of underwater construction is not limited to summer when the waves are calm, making it very easy to carry out construction. This can be done easily.

(Effects of the Invention) Since the asphalt pine of the present invention has the above-described configuration, it is possible to easily construct a foundation for construction in places affected by extremely rough waves, and the construction period can be shortened. It becomes possible to shorten the length.

In addition, the asphalt pine of the present invention bends its edges very quickly not only due to tidal currents but also due to the eddy currents newly generated by the installation of structures, forming a submarine base. Since it reliably covers the sand and gravel layer, foundations and structures built on asphalt pine can be installed in a stable state.

Furthermore, in the present invention, since the thickness of the asphalt pine and the reinforcing members inserted therein can be arbitrarily formed, it is possible to form the asphalt pine according to the conditions of the construction site. This makes it possible to significantly reduce the construction period and cost compared to when asphalt pine is not used.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway plan view showing the structure of an asphalt pine according to the present invention, FIG. 2 is a sectional view thereof, and FIG. Figures 4A to 4C are explanatory diagrams showing the bent state of the end of the asphalt mat, respectively. Codes in the diagram 1... Asphalt pine, 2...
... Asphalt mastic, 3 ... Reinforcement member, 5
... wire rope, 6 ... eye, 7 ... anti-slip fitting, 8 ... band iron, 10 ... weight member, 11 ...
...Chain, 12...Seafloor ground, 13...Concavity,
15...hole.

Claims (1)

[Scope of Claims] 1. In an asphalt mast formed to a predetermined thickness by inserting a reinforcing member between the layers of asphalt mastic, a water-permeable material is provided around the asphalt mast with a thickness substantially equal to the thickness of the mast having a predetermined width. 1. An asphalt mat characterized by having a layer of a weight member to which a heavy member such as a chain having properties is integrally attached. 2 A reinforcing member is inserted between the asphalt masts, and in the asphalt mast formed to a predetermined thickness, a large number of holes are formed in the surrounding area of the asphalt mast, extending vertically through the asphalt mast over a predetermined range. In addition to forming the perforated portion, a layer of a weight member formed by attaching a heavy member such as a chain to the surrounding portion of the pine is provided. Asphalt Matsut.