JPH0660558B2 - Sediment pumping method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for pumping earth and sand, and more particularly to improvement of a method for pumping earth and sand by a pump.

<Prior art> As is well known, there are shield construction methods as a method of constructing a tunnel such as a subway tunnel, and various construction methods are provided, but recently, a shield construction method using a sealed shield machine is relatively used. It is used a lot.

In the closed shield method, a chamber is usually formed on the front side of the shield machine, the chamber is filled with excavated earth and sand, and the pressure in the chamber is increased to face the face.

Then, the excavated earth and sand filled in the chamber chamber will be discharged to the outside while the collapse of the face is prevented with the promotion of the shield machine, but at this time, if the excavated earth and sand is not fluid, it will be difficult to discharge it. .

Therefore, a method of adding and mixing a spherical superabsorbent resin as an antifriction material in order to impart fluidity to the excavated soil has been disclosed in Japanese Patent Laid-Open No.
It is disclosed in Japanese Patent Publication No. 2-211491.

According to the method disclosed in this publication, when a spherical highly water-absorbent resin is added to and mixed with excavated earth and sand, the bearing effect of the resin facilitates discharge.
There was a technical problem as described below when pumping the excavated sediment.

<< Problems to be Solved by the Invention >> That is, according to the experiments of the present inventors, when pumping the excavated soil by the method disclosed in the above publication, the excavated soil can be provided with fluidity enough to be pumped. It was found that there is a problem that the excavated soil mixed with the spherical superabsorbent resin has a large number of gaps, and that the water tends to precede the transport pipe during pumping to easily close the transport pipe.

The present inventors repeated various experiments in order to eliminate such a problem, as a result, it is known that such a problem disappears by using a special superabsorbent resin, based on this knowledge The present invention has been completed by the above, and an object of the present invention is to provide a method for pumping earth and sand which can obtain fluidity necessary for pumping by pumping and can be pumped without causing clogging of a transport pipe. is there.

<< Means for Solving the Problems >> In order to achieve the above object, the present invention is a method of mixing an antifriction material with earth and sand and pumping it through a pump. A gel of water-absorbent resin,
Containing potassium acrylate and a water-miscible or water-soluble divinyl compound, the concentration of the monomer is 55-80% by weight
The water-absorbent resin consisting of a dried solid polyacrylate cross-linked product obtained by adding a polymerization initiator to a water-soluble substance in a range of It is characterized by using a gel made of a dry solid.

<< Operations and Effects >> According to the sediment feeding method of the above configuration, the continuous superabsorbent resin gel is used as an antifriction material to be mixed with excavated sediment, and is potassium acrylate and water-miscible or water-soluble divinyl. And a water-based solution containing a system compound and having a monomer concentration in the range of 55 to 80% by weight to allow the polymerization reaction to occur without external heating by adding a polymerization reaction initiator. The gel made from the water-absorbent resin dry solid consisting of the polyacrylate cross-linked dried solid obtained by vaporizing is a gel of an amorphous continuous superabsorbent resin, so this gel is between the soil particles of excavated earth and sand. Will be intervened in a state of being filled, the fluidity will be increased, and almost no gap will be formed.

<Example> Hereinafter, a preferred example of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an experimental device that was conducted to confirm the effects of the present invention.

In this experiment, a spherical super absorbent resin A (trade name A-II
I) and a highly water-absorbent resin C (trade name ALASORP S-100 (manufactured by Arakawa Chemical Industry Co., Ltd.), which becomes an amorphous continuous gel, are prepared, and the pressure retention property when these are added and mixed with earth and sand And the water-stopping property were checked to determine the suitability for pumping.

Here, ALASORP S-100 (manufactured by Arakawa Chemical Industry Co., Ltd.) is related to the application of the Arakawa Chemical Industry Co., Ltd.
Japanese Patent Publication No. 2-14925 (Japanese Patent Laid-Open No. 58-71907).
It is equivalent to a water-absorbent resin dry solid produced by the production method described in Japanese Patent Publication No.

As an experimental device, a sample soil tank 10 containing sample soil is used.
0 (inner diameter 300φ x height 500 mm) and this tank 10
0 and a water tank 103 connected via cocks 101 and 102 are prepared, a pressure gauge 104 and an opening cock 106 are attached to the upper end of the sample soil tank 100, and the tank 100
A pipe 108 having a solenoid valve 107 was connected to the lower end of the. An open cock 109 and a compressed air supply pipe 110 were attached to the upper end of the water tank 103.

As the earth and sand material to which the above superabsorbent resins A and C were added, bean gravel having a diameter of 5 mm with extremely uniform particle size distribution was prepared as gravel. The soybean gravel was drained before being mixed with the superabsorbent resins A and C so that the saturation was S _r = 100% and the unit deposition weight was γ _t = 1.94 gf / cm.

The gel of the super absorbent resins A and C and the sample soil were prepared by the following method.

Gel creating super absorbent polymer A, with respect to C of the powder weight W _{G (g),} allowed to absorb water tap water 1 kg (1 liter) was used after standing for 24 hours.

Gel concentration _C G of this time (%) is to be represented as _{C G (%) = W G} /1000×100=0.1W G.

Preparation of sample soil For the gravel 10 after draining,
Was added and mixed well to make a sample soil.

Each of the sample soils obtained as described above was filled into the sample soil tank 100 so as to have a height of about 45 cm while being lightly compacted with a projecting rod in three layers. Next, the cock 101 and the solenoid valve 107 were opened, the cock 102 was opened above the sample soil to inject water, and at the same time, the open cock 106 was opened to remove air. Then, the solenoid valve 107 was closed when water permeated the sample soil and started to flow out from the pipe 108.

As described above, at the stage where the air removal from the sample soil tank 100 and the penetration of water into the sample soil are completed, each cock 1
The sample soil was pressurized with water while 06 and 107 were closed and the cocks 101 and 102 were opened. The set pressure in the sample soil tank 100 due to the pressurization of the water supply is 0.5, 1.0, 1.
The pressure is set to 5, 2.0 kgf / cm ² , and when these predetermined pressures are set, the cock 101 is closed to keep the pressure in the sample soil tank 100 in that state. Then, set the solenoid valve 107 to 1
It was opened for 0 seconds, and the pressure holding state in the sample soil tank 100 during that time was measured and recorded every 0.005 seconds via the pressure gauge 104. The amount of water flowing out of the pipe 108 during this time was also measured with the beaker 111.

2 to 4 show the measurement results obtained in the pressure holding test.

FIG. 2 shows the measurement results in the case where no super absorbent polymer gel was added, and the pressure in the sample soil tank 100 became atmospheric pressure 0.7 seconds after the electromagnetic valve 107 was opened, and the water pressure was maintained thereafter. The pressure will be negative as the outflow continues. Table 1 shows the amount of runoff water at this time. As a matter of course, the higher the set pressure in the sample soil tank 100, the larger the outflow amount.

FIG. 3 shows a case where a spherical gel of super absorbent polymer A is used. In this case, the solenoid valve 107 is opened 6-7.
After a second, the pressure in the sample soil tank 100 became atmospheric pressure.
During this time, the amount of water flowing out from the solenoid valve 107 was increased by about 2 times, as compared with the case where no gel was added, because the pressure retention was good. The gel concentration is C _G = 1.2%
And

FIG. 4 shows the case where the super absorbent polymer C which is an amorphous continuous gel according to the present invention is used.

That is, Arasorb S-100 as the super absorbent resin C is used.
When the gel concentration is C _G = 0.6% (half in the case of the super absorbent polymer A), the pressure holding property is much better than that when the super absorbent polymer A is used. There
The pressure in the sample soil tank 100 is set by opening the solenoid valve 107.
Very little fluctuation even after a second.

Also, the amount of water flowing out was reduced to 50% or less of that of the super absorbent polymer A, and extremely good waterproofness was recognized.

In the above results, good pressure retention indicates that voids are unlikely to occur in the sediment, and good water stopping capability means that when pumping the sediment, water is pumped from the sediment by the pressure of the pump. It is less likely to be sent separately, and there is no fear that water will precede and block the transport pipe during pumping.

[Brief description of drawings]

FIG. 1 is an explanatory view of an experimental apparatus carried out to confirm the action and effect of the method of the present invention, and FIGS. 2 to 4 are graphs showing results of a pressure holding test carried out using the experimental apparatus. . A: Spherical super absorbent resin C: Indeterminate continuous super absorbent resin

Claims (1)

[Claims] 1. A method of mixing an antifriction material with earth and sand and pumping it through a pump, wherein the antifriction material is a gel of a continuous superabsorbent resin, which is miscible with potassium acrylate and water. A water-soluble divinyl-based compound is added to a warm aqueous solution in which the concentration of each monomer is in the range of 55 to 80% by weight,
Use a gel made of a water-absorbent resin dry solid composed of a dry solid of a polyacrylate cross-linked product obtained by adding a polymerization initiator to carry out a polymerization reaction without external heating and vaporizing water. A method for pumping earth and sand.