JPH0633603B2 - Method of injecting sediment composition into water - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for injecting earth and sand composition into water, which is used when embankment at the bottom of a water and artificial islands is constructed, and particularly to prevent water pollution during the operation. On how to do.

<< Background of the Invention >> When constructing embankments or artificial islands on the bottom of rivers, lakes, seas, etc., earth and sand are put into water. However, in this general sediment, since the sediment particles are separated and settled in water, the coarse particles settle and deposit first, and the fine particles settle slowly and are suspended in water. Due to the large amount of sedimentation in the upper layer of the soil, the ground that was created is non-homogeneous, and the water content is very high in the part that contains a large amount of fine particles, and it is extremely soft. It was

Therefore, the present applicant has previously developed a sediment composition which is a mixture of general sediment and a binder or these and a curing agent.
The binder of this earth and sand composition gives a caking property between earth and sand particles,
In addition, it is a material that secures a predetermined fluidity, and the curing agent is a material for solidifying earth and sand. Therefore, this sediment composition does not separate into pieces when it is poured into water, but it settles almost as a unit, so that it deposits in a very homogeneous state, and the uptake of water in water after a while is small. There is an advantage that it is possible to maintain a dense state with little decrease in density.

<< Problems to be Solved by the Invention >> However, even with such a soil-and-sand composition, the soil-and-sand particles may be separated when being poured into water, and the water quality may be polluted in the vicinity of the discharge portion.

The causes are (1) the particle size of the sand in the sand composition is fine, (2) the fluidity of the composition in the mixed state is too large, (3) the discharge rate is high, and the like.
Therefore, it may be introduced into the water in a state where the factors (1), (2), and (3) are removed, but in reality, all of these factors cannot be removed.

As a measure to prevent underwater pollution, the placement site is closed,
Pump up the water inside the deadline according to the casting height,
Although it is common to discharge after coagulating sedimentation treatment,
This method requires a separate coagulation sedimentation basin, which is extremely expensive especially for offshore construction.

The present invention has been made in view of the above problems, and it is possible to completely prevent the occurrence of pollution by intensively taking measures to prevent pollution at the discharge end of the discharge pipe, which is the source of pollution. With the goal.

<< Means for Solving Problems >> In order to achieve the above-mentioned object, the present invention is to discharge the earth and sand composition obtained by mixing earth and sand, a binder and a hardening agent into water through a discharge pipe, and It is characterized in that the coagulant is jetted from the vicinity of the discharge end of the discharge pipe to the suspended sediment of the discharged sediment.

<Operation> Suspended particles rising near the discharge end will immediately contact the flocculant and will be aggregated and deposited.

<< Embodiment >> FIG. 1 shows a first embodiment of the method of the present invention.

In the figure, 1 is a discharge pipe whose discharge end 1a is directed to the submarine ground E, 2 is parallel to the outer peripheral portion of the discharge pipe 1, and the spouting end 2a is located at the periphery of the discharge end 1a. It is a pressure pipe.

The earth and sand composition is supplied into the discharge pipe 1 by a pressure feed pump (not shown), and the earth and sand composition 3 is discharged from the discharge end 1a to deposit a layer of the earth and sand composition 3 on the water bottom ground E.

The earth and sand composition 3 is a general earth and sand, and a caking agent that gives a caking property between the earth and sand particles and secures a predetermined fluidity,
It contains a hardening agent which hardens between the earth and sand particles and solidifies the earth and sand.

The binder is composed of a water-soluble natural, semi-synthetic or synthetic polymer, and has a function of separating each particle by a kind of pasty substance and preventing water from being taken in.

Explaining the binder specifically, examples of water-soluble natural polymers include various starches, konjac fukin, agar, sodium alginate, trourooi, tragone gum, gum arabic, dextrin, levan, glue, gelatin, casein, collagen and the like. To use.

Examples of water-soluble semi-synthetic polymers include viscose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, soluble starch, carboxymethyl starch, dialdehyde starch and the like.

As the water-soluble synthetic molecule, polyvinyl alcohol, sodium polyacrylate, polyacrylamide, polyethylene oxide or the like is used.

The curing agent is one or a combination selected from ordinary Portland cement, blast furnace cement, fly ash cement, other cement materials, lime-based materials such as slaked lime, asphalt-based materials, and blast-furnace slag-based materials. . Then, this type of hardening agent has a function of solidifying and stabilizing the soil quality of the earth and sand after charging, and improving its strength.

In addition, the mixing ratio of each binder and hardening agent to the earth and sand is 10 in consideration of the economic efficiency and the degree of achievement of hardening.
1 to 5 parts by weight of binder and 50 to 50 parts by weight of hardener
300 parts by weight is the most preferable value.

Furthermore, these compositions 3 are mixed with water and are introduced in the state of a slurry from the discharge end 1a of the discharge pipe 1, and there is almost no possibility of suspension as compared with general earth and sand. In the case where the particle size is small or the discharge speed is high, the suspension layer 4 shown by a set of dots in the figure is formed at the periphery of the discharged portion. Here, the suspension layer 4 contacts the coagulant ejected from the ejection end 2a of the coagulant pressure-feeding pipe 2,
It immediately aggregates and settles on the deposited sediment composition, which prevents pollution.

As for the shape of the ejection end 2a, by providing a large number of fine nozzle portions, the contact establishment with the suspension layer 4 can be enhanced, and the contamination can be almost completely prevented.

As the aggregating agent, inorganic aggregating agents such as PAC and sulfuric acid band or polymer aggregating agents may be used alone or in combination.

In this case, the polymer flocculant alone is usually sufficient for construction in a sea area containing salt.

On the other hand, when they are used in combination, it is desirable that these aggregating agents are pressure-fed by separate pipes and the pipes are arranged so that the inorganic aggregating agent comes into contact with them first.

It has been confirmed that 1 to 5 g of the polymer flocculant per 1 m ^{2 of the} suspension layer 4 can be used to completely prevent water contamination.

Next, FIG. 2 shows a second embodiment of the method of the present invention.

In the figure, the suction end 10 a of the submersible pump 10 is located on the periphery of the discharge end 1 a of the discharge pipe 1. Further, the ejection end 2b of the coagulant pressure-feeding pipe 2 is the suction end 1 of the submersible pump 10.
It is located at 0a.

In the above configuration, by driving the submersible pump 10 in a state where the sediment composition 3 is discharged from the discharge pipe 1, the suspension layer 4 rising to the periphery of the discharge end 1a is all sucked to the suction end side of the submersible pump. At the same time, coagulant pressure feed pipe 2
The aggregating agent ejected from the ejection end 2b of the above is also taken into the submersible pump 10 from the suction end 10a. The suspension layer 4 and the coagulant are contact-mixed in the submersible pump 10, and in this state, the suspension layer 4 and the coagulant are discharged from the discharge end 10b of the submersible pump 10.

The discharged suspension layer 4 is settled early by the coagulating action of the coagulant and deposited on the water bottom ground E.

In this embodiment, since the suspension layer rising from the discharge end 1a is forcibly sucked and brought into contact with the coagulant, a more reliable pollution prevention effect can be obtained.

<Effects of the Invention> As described in detail in each of the above examples, according to the method of the present invention, since it is possible to completely prevent pollution when the earth and sand composition is poured into water, a separate coagulating sedimentation pond as in the conventional case is used. Since it is not necessary to provide an air conditioner or to transport the polluted water to another place, it is possible to implement the pollution prevention measures at the time of the submersion at an extremely low cost.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an underwater charging method according to a first embodiment of the present invention, and FIG. 2 is an explanatory view showing an underwater charging method according to a second embodiment of the present invention. 1 ... Discharge pipe, 1a ... Discharge end 2 ... Coagulant pressure feed pipe, 2a, 2b ... Jet end 3 ... Sediment composition

Claims (1)

[Claims] 1. A sediment composition obtained by mixing sediment, a binder, and a hardening agent is discharged into water through a discharge pipe, and the suspended sediment of the sand discharged into the water is discharged. A method for injecting a sediment composition into water, characterized in that a coagulant is ejected from the vicinity of the ejection end of the ejection pipe.