JPH0615762B2 - Suction prevention method for revetment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a construction method for preventing landfill sand from being sucked out in revetment work.

[Conventional technology]

The asphalt mat is a mixture of asphalt, stone powder (filler), sand, and crushed stone that is precast on land to form a mat, and contains some reinforcing material. This asphalt mixture has no void and has fluidity at high temperature, does not need compaction, has watertightness and flexibility, and has various strengths and specific gravities required as a structure, The compounded one has excellent properties such as a large coefficient of friction with concrete and rubble.

Therefore, as a method of using such an asphalt mat, for example, in the case of providing a dam body 2 facing the sea 1 as shown in FIGS. 3 and 4, this dam body 2 directly faces the open sea,
Since it receives high waves, even if there are a plurality of layers of Tetrapot 3 (registered trademark) and there is a wider layer of the rubble foundation 4, there is a possibility that the landfill sand 5 on the back surface will be sucked by the invading seawater. Therefore, an asphalt mat 6 is laid on the back surface to prevent the landfill sand 5 from leaking.

In the figure, 2a is concrete for the bottom plate of the bank 2, 7 is basic concrete therebelow, and 8 is a road constructed on the landfill sand 5.

[Problems to be Solved by the Invention]

The asphalt mat 6 should be extended slightly along the foundation ground, and the seam with the concrete levee at the top should be paved with sand mastic to ensure watertightness. Has a stack of about 1.0 m.

In this case, the asphalt mat 6 itself has a considerable watertightness, and its end portion is also firmly and watertightly pressed, so that a complete impermeable layer is formed.

However, in such a structure, in order to ensure the stability of the cross section of the bank 2, the residual water level at the time of design is 2/3 (HWL-LW
L).

HWL: Water level at high tide LWL: Water level at low tide On the other hand, if a permeable layer is used instead of an impermeable layer, the residual water level may be 1/3 (HWL-LWL), which is the cross section of the bank 2. Can be made small and economical. For example, a small caisson is required when constructing the dam body 2 using caisson.

In addition, if there is a completely impermeable layer, the water quality in the landfill will deteriorate.

An object of the present invention is to solve the above-mentioned disadvantages of the prior art, and to provide a method for preventing the revetment from leaking out, which makes it easy to install an asphalt mat and can easily and easily widen a water-permeable portion as needed.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, in the case of laying an asphalt mat for preventing spillage in landfill sand below a bank, a mat-shaped water-permeable material whose surface is covered with a protective net along the edge of the asphalt mat. Is preliminarily attached, and the asphalt mat is hung, and an end of the asphalt mat opposite to the side where the water permeable material is attached is placed on the water permeable material at the end of the already laid asphalt mat. The main idea is to lay it.

[Action]

According to the present invention, since the water-permeable material is attached along one end of the asphalt mat in advance, the water-permeable material and the asphalt mat can be simultaneously hung as a unit, and the other end of the asphalt mat is already installed. It can be easily installed by just placing it on the permeable material.

In addition, since there is a permeable layer formed of a permeable material, the residual water level is small and it is economical, and there is no risk of water quality deterioration in the landfill.

Further, its water permeability can be freely set by adjusting the ratio between asphalt mats and changing the size of the water permeable material, and this water permeable material becomes more durable due to the protective net.

〔Example〕

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of a method for preventing spillage of a revetment of the present invention, and FIG. 2 is a vertical sectional side view of an essential part of the same, and 6 in the drawing shows an asphalt mat.

The asphalt 6 is laid in the landfill sand 5 under the bank 2 as shown in FIGS. 3 and 4 for preventing the landfill sand from being sucked out.

When the asphalt mat 6 is laid, the mats 6 adjacent to each other have an appropriate interval, and the water permeable material 10 having the surface covered with the protective net 9 is arranged at this place.

These materials are not particularly limited, but as an example, the water-permeable material 10
As the material, a fiber-based material in which a resin is appropriately hardened may be considered. Further, as the protective net 9, a nylon net or a metal net such as a wire mesh or the like is suitable, which has a large open-cut.

The water-permeable material 10 and the protective net 9 are integrally formed in a mat shape, and the edge thereof is attached to the lower surface of one edge of the asphalt mat 6 to be laid in advance.
As the attachment method, welding when molding the mat 6 can be considered.

Then, when the asphalt mat 6 is hung horizontally by a crane or the like and laid, the mat body of the water permeable material 10 and the protective net 9 is hung and laid at the same time.

At this time, the edge of the other asphalt mat 6 may be simply placed on the water-permeable material 10 already installed without being fixed. By adjusting the mounting width on the water permeable material 10, the interval between the asphalt mats 6 and 6 can be adjusted appropriately.

〔The invention's effect〕

As described above, in the method for preventing spillage of revetment of the present invention, the water-permeable material is attached in advance along one end of the asphalt mat, so that the water-permeable material and the asphalt mat can be suspended at the same time as one body. It is easy to handle, and the installation is completed simply by placing the other end of the asphalt mat on the already permeable water.

Further, in the case where an asphalt mat for preventing drainage is laid in the landfill below the levee body, it is possible to easily form the permeable layer by a necessary amount. This makes it possible to estimate the residual water level at the time of design to be low, which is economical because the cross section of the bank is small.

Furthermore, the water quality in the landfill can be prevented from deteriorating, and the permeable material to be disposed has a protective net, which makes it more durable, and is mat-like and has a certain weight, so that workability is also good.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing one embodiment of a method for preventing spillage of a revetment of the present invention, FIG. 2 is a vertical sectional side view of an essential part of the same as in FIG. 2, and FIG. FIG. 4 is an enlarged vertical side view of the main part of the same. 1 ... Sea, 2 ... Embankment 2a ... Bottom slab concrete 3 ... Tetra pot, 4 ... Rubble foundation 5 ... Landfill sand, 6 ... Asphalt mat 7 ... Foundation concrete 8 ... Road, 9 ... Protective net 10 ... Water-permeable material

Claims (1)

[Claims] 1. When laying an asphalt mat for preventing spillage in landfill below the bank, a mat-shaped water-permeable material whose surface is covered with a protective net is previously attached along the edge of the asphalt mat. , Hang the asphalt mat, and lay the end of the asphalt mat opposite to the side where the water permeable material is attached on the water permeable material at the end of the asphalt mat that has already been laid at an appropriate interval from the asphalt mat. A method to prevent the seawall from leaking out.