JPH04194218A - Underwater banking method - Google Patents

Abstract

PURPOSE:To prevent a fall of strength and weight per unit volume of underwater banking and water pollution by constructing underwater banking in an acryl series coagulant solution territory formed through injecting acryl series coagulant solution into a water area to be constructed the underwater banking. CONSTITUTION:An injection pipe 5 and a suction pipe 6 connected to an acryl series coagulant solution tank 4 in a working ship M are provided in parallel with a tremie pipe 1 with a fixing member 7. Low concentration acryl series coagulant solution 3 is injected into a covered body 4 of the lower part of the tremie pipe 1 through the injection pipe 5, sucked with the suction pipe 6, and hence circulated to form an acryl series coagulant solution territory 3a so as not to be diffused in the covered body 4. Banking material 2 is charged into the acryl series coagulant solution territory 3a through the tremie pipe 1, and underwater banking 2a is constructed on the bottom of the water N. Hereby, quality and accuracy of the underwater banking 2a can be insured, and water pollution can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an underwater embankment construction method for constructing an embankment by casting underwater embankment materials underwater.

(Prior Art) When constructing an embankment underwater, there are methods such as pouring sand, earth, etc. alone, or pouring an embankment material mixed with a solidifying material such as sand, gravel, or cement.

However, when this embankment material is mixed with solidifying materials such as sand, gravel, and cement, the sand, gravel, and cement do not have adhesive strength, so when they are put into water and come into contact with water, these particles separate. There was a problem that the material became non-uniform, making it impossible to obtain a desired quality and causing water pollution.

In order to solve these problems, a method has been developed in which an additive such as a thickener is added to the embankment material and the additive is poured into water.

(Problems to be Solved by the Invention) However, the embankment material to which a thickener or the like as described above is added has a problem in that the strength and unit volume weight of the underwater embankment decrease due to the use of the thickener.

Therefore, the present invention was made in view of the above problems, and its purpose is to provide an underwater embankment construction method that prevents a decrease in the strength and unit volume weight of an underwater embankment and does not cause water pollution. It is.

(Means for Achieving the Object) In order to achieve the above-mentioned objects, the underwater embankment construction method of the present invention involves injecting an acrylic flocculant solution into the water body where the underwater embankment is to be constructed. The present invention is characterized in that an underwater embankment is constructed by forming a solution area and placing embankment materials within the acrylic flocculant solution area.

(Function) According to the underwater embankment construction method having the above structure, when an acrylic flocculant solution is injected into the water area where the underwater embankment is constructed, an acrylic flocculant solution area is formed in the water area near the bottom of the water. be done.

When the embankment material is placed in the acrylic flocculant solution area, the embankment material is covered with the acrylic flocculant solution and placed on the bottom of the water in a state isolated from the water. does not separate, thereby preventing a decrease in strength and unit volume weight, and causing no water pollution.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

The drawing is a sectional view showing the underwater embankment construction method of the present invention, in which the embankment material 2 is put into water through a tremie pipe 1, and the underwater embankment 2 is
This is to construct a.

The tremie pipe 1 is connected to a work boat M such as a offshore work boat or a floating work barge by a chain or wire m, and the tip thereof is connected to the bottom N.
It is suspended so as to be located nearby, and an umbrella-shaped covering 4 is provided at the tip.

Further, in the tremie tube 1, an injection vibrator 5 and an absorption vibro connected to the acrylic coagulant solution tank 4 of the work boat M are provided parallel to the tremie tube 1 by means of a fixing member 7, and the tip of the injection vibrator 5 is connected to the The top of the covering 4 and the tip of the absorbing vibro are connected to the bottom of the covering 4, respectively.

Then, inject 5 to 10 pp into the coating body 4 using the injection vibrator 5.
By injecting an acrylic flocculant solution 3 with a low concentration of about m, and absorbing it with an absorption vibro and circulating it appropriately, an acrylic flocculent solution region 3a is formed, and it is diffused in the covering 4. I try not to.

Then, the embankment material 2 is introduced into the acrylic flocculant solution region 3a formed in the covering body 4 through the tremie pipe 1. At this time, the tip of the tremie tube 1 has a lid (
(not shown), and the embankment material 2 is thrown into the water bottom N in a state covered with the acrylic flocculant solution 3 without coming into contact with water at all.

Then, as shown in the figure, when the filling material 2 progresses, the tip of the tremie pipe 1 is covered with the filling material 2, so the filling material 2 that is successively introduced does not come into contact with the acrylic flocculant solution 3 at all. Then, the underwater embankment 2a is constructed.

In this way, only the surface of the embankment material 2 comes into contact with the acrylic flocculant solution 3, and the inside does not come into contact with water or the acrylic agglomerate solution 3 at all, so it is not affected by them, ensuring quality accuracy of the embankment material 2. be able to.

Next, an experimental example of the present invention will be shown below.

(Experiment example) Using the construction method of the present invention, 1469 kg of mountain sand and cement (
8 types of blast furnace cement > 143 kg and 388 kg of water were mixed and poured into a small water tank, and the conventional construction method was used to mix 1230 kg of mountain sand and cement (blast furnace cement 8
seeds) 150Kg, water 150Kg, and thickener 3K
The following table shows the experimental results of measuring the strength and unit volume weight when the mixture was mixed with g and poured into a small water tank using a double tremie tube.

From the experimental results shown in the table, it was possible to confirm the following effects of the present invention.

(Effects of the Invention) By having the above configuration, the present invention has the following effects.

■ Since there is little contact between the underwater embankment material and water and the acrylic flocculant solution, the quality and accuracy of the embankment can be ensured.

■ The simple structure of the underwater embankment method makes it easy to handle and prevents water pollution.

[Brief explanation of the drawing]

The figure is a sectional view of the underwater embankment method of the present invention. In the figure, 2: Embankment material 2a: Underwater embankment 3; Acrylic flocculant solution 3a; Acrylic flocculant solution area It is.

Claims (1)

[Claims] The submerged embankment is constructed by injecting an acrylic flocculant solution into the water area where the underwater embankment is to be constructed to form an acrylic flocculant solution area, and placing embankment materials within the acrylic flocculant solution area. Underwater embankment method.