JPS5827780A - Transportation of soil - Google Patents

Abstract

PURPOSE:To increase the thixotropy of soil, to reduce the frictional force of pressure, and to lessen the frictional force between the soil and a device, by adding a high water-absorbing high polymer which becomes a spherical elastic material after water absorption to dug soil and blending them with stirring. CONSTITUTION:A highly water-absorbing high polymer having absorbed liquid is injected to the inside of the partition wall 2 of the shielding digging machine 1 equipped with the soil discharging device 4, the high polymer is blended with dug earth and soil with stirring, the frictional resistance in a cutter is reduced, the dug soil is received once by a hopper in a pit while stopping the supply of pressurized water in the cutter and the soil discharging device 4, and it is sent by pressure to the hopper or dump truck 10 on the ground by the pressure pump 5. A saponified copolymer obtained by subjecting (A) ethylene, (B) a vinyl ester, and (C) an ethylenic unsaturated carboxylic acid (derivative) as main components in a molar ratio of A:(B+C)=(0:100)-(15:85) and a molar ratio B:C of (20:80)- (80:20) to suspension polymerization, etc. may be cited as the preferable example of the high water-absorbing high polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention improves the rockability of the soil by adding a super-absorbent polymer that becomes a spherical elastic body after absorbing water to excavated soil and stirring it. It is characterized by reducing the frictional force of. Concerning a construction method for pumping excavated soil.

As a method for continuously transporting earth and sand in a narrow space without contaminating the surrounding area, there is a construction method that uses a medium to transport the earth and sand inside a pipe.

The media include compressed air and muddy water, which are called pneumatic transport and muddy water transport, respectively. When compressed air is used, the soil must be smooth and sandy with a low moisture content, and when muddy water is used, it is difficult to separate the muddy water and sand after transporting it, which requires a lot of effort. There was a problem.

In addition, in a construction method that attempts to transport the excavated soil inside the pipe without using a medium, if the excavated soil is pumped with a pressure pump such as a concrete pump, the internal friction angle of the soil There is a problem in that the frictional force caused by this and the adhesive force caused by the adhesion of the soil occur between the pipe and the soil, and this creates a resistance force that prevents the tube from being transported over long distances.

In order to reduce the drag force in these methods of continuously transporting earth and sand, anti-friction materials are mixed with the soil.

A method has been proposed in which the material is thoroughly stirred and then pumped using a pressure pump. This anti-friction material is based on bentonite slurry, which is made by adding water, bentonite (a mineral substance), and other additives.

In this case, if more than 80% of the earth and sand are mixed, the friction reduction effect is good, but the viscosity of the earth and sand after being conveyed is high.
Difficult to dispose of.

As a result of various studies on these problems, the present inventors found that when excavated soil is mixed with a superabsorbent polymer that becomes a spherical elastic body by absorbing water, the friction reduction effect is remarkable and the superabsorbent polymer becomes a single spherical elastic body by absorbing water. The present invention was achieved by discovering that water absorption and water release occur reversibly with polymers, and there is no problem in using the transported earth and sand as embankment material, making it easier to dispose of the transported earth and sand. did.

An object of the present invention is to provide a construction method for pumping excavated soil.

In other words, by utilizing the solid properties of superabsorbent polymers that form small-diameter spherical elastic bodies, that is, their bearing action and good water retention properties, we can improve the sustainability of the anti-friction material effect and expand the adaptability of excavated soil. This made it possible.

The contents of the present invention will be specifically shown below.

The superabsorbent polymer used in the present invention is not particularly limited as long as it becomes an elastic body after absorbing water, but it is preferably an ethylene prisoner, a vinyl ester, and an ethylenically unsaturated carboxylic acid or its like. The derivative (1) is the main component, and these components are X: (Y + Z) = 0:100 to 15:85V:
A saponified product of a copolymer obtained by suspension polymerization having a molar ratio in the range of Z = 20:80 to 80:20. Crosslinked polymers of acrylic acid and/or acrylate salts obtained by reverse-phase suspension polymerization can be used.

Alternatively, crosslinked polymers of acrylic acid and/or acrylates obtained by reverse phase suspension polymerization can be used.

The water absorption rate and average particle size of the superabsorbent polymer used in the present invention, which becomes an elastic body when water is absorbed, are not particularly limited, but the water absorption rate is preferably 800 to 8000 times that of distilled water.

Regarding the particle size, after absorbing distilled water O・O1m~16
(2) A spherical elastic body is practical. The ratio of the superabsorbent polymer of these balls V to the excavated soil varies depending on the type of excavated soil or water content, and there is no particular limit, but it is generally about 0.01% to 100% of the excavated soil. be.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is a diagrammatic illustration of a typical method of carrying out the present invention.

(1) Implementation method-1 (Figure 1) A shield excavator (1) equipped with an earth removal device (screw conveyor (4)) is used to remove superabsorbent polymers that have absorbed liquid produced on the ground or underground. Injected into the bulkhead and mixed with the excavated soil as is or mixed with the excavated soil using the stirring device inside the cutter to reduce the frictional resistance inside the cutter and discharge the soil while shutting off the pressure water inside the cutter and earth removal device. Once received in the hopper inside the mine, the pressure pump (5) pumps it to the hopper (10') on the ground or directly to the dump for disposing of earth and sand. Alternatively, the soil is directly pumped to the ground using a pressure pump (5) installed in the soil removal device.

(2) Implementation method-2 (Figure 2) A shield excavator that directly discharges excavated soil from the face (
The earth and sand excavated in step 11) was discharged into a hopper using an earth and sand conveyor (belt conveyor (14)), and the earth and sand were prepared on the ground or in the mine. A method in which a superabsorbent polymer is added, mixed and stirred with excavated sand, and then the mixture is pumped using a pressure feeder (15) to a hopper on the ground or directly to a dumper for disposing of earth and sand.

In this way, the excavated soil absorbs water as a friction reducing material.

When excavated soil is pumped using a pressure pump by adding a super absorbent polymer that becomes a spherical elastic body.

This reduces pressure resistance and allows continuous transport over long distances.

In the anti-friction material of the present invention, conventionally used mineral substances, organic glues, surfactants, oils, etc. may be used together with the super absorbent polymer of the present invention which becomes a ball elastic body when absorbed. Included in the present invention.

The present invention will be explained in more detail with reference to Reference Examples and Examples below, but the present invention is not limited thereto.

Reference Example 1 0.5 g of benzoyl peroxide was added as a polymerization initiator to 6ON hynyl acetate and 40 f of methyl acrylate, and this was chlorinated with 0.2 fl of partially saponified polyvinyl alcohol (degree of saponification 88 mol%, degree of polymerization 2000). It was dispersed in 200ml of water containing 8f of sodium and subjected to suspension polymerization at 66°C for 6 hours.

Next, the copolymer aop was added to a solution of 16.2F sodium hydroxide dissolved in a mixed solvent consisting of 100% methanol and 80% water, and a saponification reaction was carried out at 80°C for 2 hours and further at 60°C for 6 hours. After the saponification reaction is completed, the product is thoroughly washed with methanol and then dried under reduced pressure.
A dried saponified product 24f having a particle size of 20 μm to 200 μm was obtained.

The saponified ball cane thus obtained is insoluble in water and swells quickly in water.

The water absorption rate for distilled water was 750 flf.

Reference Example 2 A polymerization tank was charged with 188.19 g of water, and 44.7 g of sodium hydroxide was added and dissolved with stirring. While cooling with ice, 100 g of acrylic acid was gradually added and neutralized with stirring. Potassium persulfate 0.06679 and N,N
Add 0.01f of '-methylenebisatalylamide.

Further, sorbitan monostearate 6, Of and normal hexane 700- were added and polymerized at 60°C for 8 hours with stirring.After the polymerization was completed, solid-liquid separation was performed and dried under reduced pressure to form a spherical superabsorbent polymer 125. I got 2N.

The obtained superabsorbent polymer has a particle size of 101L to i50/
'Met. Moreover, the water absorption rate was 5601/f.

Example 1 The superabsorbent polymer obtained in Reference Example 1 was used as a component of an anti-friction material, and sandy soil was mixed in various proportions.

At this time, the blending ratio of the anti-friction material was as follows.

Water 180Kf (1801)
180Kg (1801) bentonite 0
40 Matsudo oil 0
10°C MOQ o, g Higel Oo, 9 The internal friction angle and adhesive force of this mixed soil were determined by a direct shear test.

The results are shown in the wiB diagram in comparison with the case where the conventionally used bentonite mud type antifriction material is mixed with sandy soil.

What are the effects of conventional bentonite mud type anti-friction materials?

Mixing ratio of anti-friction material (weight of anti-friction material/weight of mixed soil) is approximately 16%
It is hardly noticeable when the amount is less than 16% and becomes effective rapidly between 16% and 80%.

On the other hand, the anti-friction material of the present invention is approximately proportional to the mixing ratio, and the effect of the anti-friction material is enhanced. (The coefficient of friction tan q decreases.) This is because the anti-friction material of the present invention maintains its anti-friction effect even if the soil from the ground leaks into the anti-friction material and the mixing ratio of the anti-friction agent becomes lower. This shows that the anti-friction effect is excellent when the mixing ratio is less than 80 gruel.

Furthermore, the same effect was also shown when the superabsorbent polymer obtained in reference eIIJ2 was used.

FIGS. 1 and 2 are schematic diagrams showing a typical implementation method of the present invention.

1... Shield main body, 2... Bulkhead, 8... Sediment inside the bulkhead.

4...Earth removal device, 5. -...Pressure pump.

6... Anti-friction material injection pipe, 7... Mixed soil removal pipe.

8...Gland pump, 9...Batch for injection of anti-friction material.

10...Hopper or dump, 11...Shield body.

12... Bulkhead, 18... Sediment inside the bulkhead, 14... Belt conveyor.

15... Pressure pump, 16... Stirrer, 17...
Anti-friction material injection pipe.

18... Batch for injection of anti-friction material, 19... Grand pump, 20... Pipeline for mixed soil removal.

21... Hopper or dump Figure 8 is a graph showing the relationship between the friction reducing agent mixing ratio and the friction coefficient (tan y') of the friction reducing agent mixed soil of the present invention.

The horizontal axis in the figure is the mixing ratio of anti-friction material (weight of anti-friction material/weight of mixed soil x 1)
00) (%).

Claims (1)

[Claims] l) When soil is pumped using a pressure pump, a water-absorbed spherical elastic body of a super absorbent polymer that becomes a spherical elastic body when it absorbs water is added to the soil and mixed and stirred. A method to increase soil oscillation and reduce pressure resistance. 2) A highly water-absorbing polymer that becomes a spherical elastic body when it absorbs water is mainly composed of ethylene captive, vinyl ester (1), and ethylenically unsaturated carboxylic acid or its derivative α).
These components are X: (Y+Z)=0:100~15
The method according to claim 1, which is a saponified product of a copolymer having a molar ratio of :85Y:Z = 20:80 to 80:2%. 8) The method according to claim 1, wherein the superabsorbent polymer that becomes a spherical elastic body upon absorption of water is an acrylic acid and/or arylate crosslinked polymer.