JPH01190812A - Artificial ground construction method - Google Patents

Abstract

PURPOSE:To form artificial grounds efficiently and in low cost by stuffing a hydrated gellike substance as a backfilling material, and on the upper part thereof by forming surface material layers. CONSTITUTION:In the base rock of a porous sea bottom 1, between inner and outer double ring-shaped steel sheet plates 3 and inside the inner plate, a gelling agent 7 consisting of an urethane constituent is poured and solidified. Then, surface material layers of polyethylene-made boxes 9, synthetic resin foam boards 10, and concrete floors 11 are laid. Thus, artificial grounds can be constructed in a good operational efficiency, and in low cost.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a method for constructing artificial ground, and more specifically, to a method for constructing artificial ground, and more specifically, in a lagoon surrounded by a coral reef, where it is difficult to use backfilling materials such as sand and earth. The purpose of this paper is to propose a construction method suitable for constructing artificial ground such as rocky reefs.

[Problem that the invention seeks to solve]

When constructing artificial ground on rocky reefs in lagoons surrounded by coral reefs, it is difficult to obtain sand, gravel, soil, and other solid materials required for backfilling at the construction site. Transporting these backfill materials from remote locations is often difficult.

This invention was made in view of the above circumstances. The purpose of this study is to propose a construction method for artificial ground that does not use sand, earth, or the like as backfill material, but gels seawater, groundwater, tap water, etc., and uses this gel as backfill material or embankment material.

[Means for solving problems]

This method of constructing artificial ground is characterized by filling a water-containing gel material as a backfilling material or embankment material, and forming a surface material layer on top of the water-containing gel material.

The backfilling material is made by adding a gelling agent to water obtained near the construction site, such as seawater or groundwater, to form a hydrous gel-like material. Examples of gelling agents include urethane compositions whose main component is a reaction product of polyols and isocyanels.

When this composition comes into contact with water, the isocyanate groups react with the water, take up a large amount of water, and turn into a gel to form a strong rubber-like solid, which has physical properties that can be used as a backfilling material.

When using a hydrous gel material as a backfill material, if the volume of the backfill space is large, it is difficult to mix water and gelling agent uniformly to create a hydrogel material, so it is usually packed in bags. Or it is used in boxes. If the bag or box is made of water-impermeable and durable materials such as synthetic resin,
The stability and durability of the backfilling material are improved, making it more suitable.

As the surface material layer, in addition to a concrete floor, an asphalt floor, a pressure regulating plate, etc. can be used.

〔Example〕

The following will explain the embodiments shown in the drawings. This example is an example of constructing an artificial ground centering around a rocky reef in a lagoon surrounded by coral reefs that appear on the sea surface at low tide and become the seabed at a depth of 5 m at high tide. The ocean floor consists of the remains of coral reefs.
The ground was sufficiently solid, and the condition was that nothing other than minor buildings would be built on the artificial ground.

To construct this artificial ground, as shown in Figure 1.2, steel sheet piles are placed on the coral reef seabed 1 along two circles with a radius of 20 m and 25 m centered on the reef 2 that is above the sea surface even at high tide. 3.Make a sheet pile cell by doubling 3 and 3. The sheet piles 3 are 10 m in length, and the inner and outer sheet piles 3, 3 are connected in a ring, and C-shaped copper hoops 4, 4 are arranged at the upper ends of the surfaces of the inner and outer sheet piles 3, 3. 4. Fasten and connect between 4 with tie rod 5. In addition, a synthetic resin film 6 is applied to the inner surfaces of the sheet piles 3, 3 to provide waterproof performance, and the sheet piles 3
Corrosion prevention measures such as electrical corrosion protection are taken (not shown).

As shown in Fig. 3, between the steel sheet piles 3.3 and 3, which have an annular double inner and outer ring structure, a gelling agent 7 (made of the above-mentioned urethane composition) ( 4 poly grout (manufactured by Daiichi Kogyo Seiyaku ■) is injected and solidified, glass wool 8 is buried on the seabed 1, and the gelling agent 7 is injected into it. creates a nearly flat consolidated layer. Next, a polyethylene rectangular parallelepiped box 9 filled with a water-containing gel obtained by adding a gelling agent of a urethane composition to seawater is packed to a height of 4 m, and a 1 m thick synthetic box 9 is placed on top of it. A resin foam board 10 is placed, and a surface material layer made of a concrete floor 11 with a thickness of 0.5 m is placed thereon to form a wave-dissipating ring made of double sheet vile cells.

The concrete floor 11 is made of small blocks as much as possible, and is arranged separately from the tie rods 5. The foam board 8 is preferably a hydrophobic material that does not contain water, such as a closed-cell polystyrene foam board or a high-density polyethylene foam board, and is used in small pieces.

In the interior surrounded by this wave-dissipating ring, glass wool 6 is buried on the seabed 1, and gelling agent 7 is injected to create a solidified layer with a flat top surface, as in the space between the sheet piles 3 and 3. A box 9 filled with a gel-like substance containing seawater is packed on top of the box 9, a synthetic resin foam board 10 is placed on top of the box 9, and a surface material layer consisting of a concrete board 11 is placed on top of the box 9. In addition, on the top surface of the concrete plate 11, there are 3
The stepped portions of the steps form a water gradient that gradually becomes lower toward the outside.

[Action and effect of the invention]

This invention consists of the above configuration. This artificial ground construction method uses a gel-like material containing water as the backfilling material, so
There is no need to use sand, gravel, earth, etc., and it is possible to backfill and construct an artificial ground using only a very small amount of gelling agent compared to the amount of backfilling material.

Therefore, according to this construction method, it is possible to construct artificial ground on a remote coral reef or the like with high work efficiency and at low cost.

[Brief explanation of the drawing]

The drawings show an example of constructing artificial ground on a coral reef. Figures 1 and 2 are perspective views and A-A sectional views of steel sheet piles built in a ring shape, and Figure 3 is a longitudinal section of the artificial ground. It is a front view. 1...Coral reef seabed, 2...Rocky reef, 3
... Steel sheet pile, 4 ... Hoop material, 5 ...
... Tie rod, 6 ... Synthetic resin film, 7
...Gelling agent, 8...Glass wool,
9...Box, 10...Synthetic resin foam board,
11... Concrete board. Figure 3

Claims (1)

[Claims] (1) Filling with water-containing gel material as backfilling material or embankment material,
An artificial ground construction method characterized by forming a surface material layer on top of it.