JPS61225275A - Mud leakage inhibitor for shield method - Google Patents

Abstract

PURPOSE:To provide the titled mud leakage inhibitor having improved resistance to electrolyte, consisting of a water-insoluble, water-absorbing resin, a water-soluble high-molecular compd. and an inert org. liquid. CONSTITUTION:5-65wt% mixture of a water-insoluble water-absorbing resin (A) (e.g. a hydrolyzate of a starch/acrylonitrile graft copolymer) and a water-soluble high-molecular compd. (B) (e.g. hydroxyethylcellulose) in a ratio of 1:0.1-10, is mixed with 95-35wt% inert org. liquid (C) (e.g. polyethylene glycol) which is a liquid at a temp. of -10-50 deg.C, neither swells nor dissolves component A and is non-reactive with component A, thus obtaining a mud leakage inhibitor. The mud leakage inhibitor is slurried, and introduced through the emergency inlet of a shield machine into the mixing chamber thereof under pressure and then into soil, whereby the inhibitor absorbs water, swells and is caused to gel.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an anti-sludge agent for shield construction methods.

[Conventional technology]

BACKGROUND ART Conventionally, sludge prevention agents have been known that are combinations of superabsorbent resins and oils. However, this product has problems in terms of electrolyte resistance, such as when electrolytes such as cement and seawater are mixed in, the electrolyte resistance decreases significantly.

[Problem that the invention seeks to solve]

The present inventors have arrived at the present invention as a result of intensive studies aimed at improving electrolyte resistance in the above technology.

[Means to solve the problem]

The present invention is a sludge prevention agent for shield construction, characterized by comprising a water-insoluble water-absorbing resin (a), a water-soluble polymer (b), and an inert organic liquid (c).

In the present invention, the water-insoluble water-absorbing resin (a) includes a water-soluble monomer and/or a monomer (3) that becomes water-soluble upon hydrolysis, starch and/or cellulose [F]) and/or Examples include polymers obtained by polymerizing with a crosslinking agent (C) as an essential component and, if necessary, performing hydrolysis. The water-soluble monomer (2) used in the production of the above polymer includes at least one hydrophilic (for example, carboxyl group, carboxylic acid anhydride group, carboxylic acid group, A monoethylenically unsaturated monomer having a hydroxyl group, an ether group, an amide group, an amino group, or a quaternary ammonium base can be used. As the monomer that becomes water-soluble by hydrolysis, a monomer having at least one hydrolyzable group (ester group, nitrile group, etc.) can be used.

The manufacturing method of this water-absorbing resin and specific examples of the water-absorbing resin are disclosed in JP-A-51-125468, JP-A-52-25886,
This is explained in detail in JP-A-52-5%90 and JP-A-58-149190.

Water-absorbing resins other than those mentioned above include those obtained by polymerizing silane and (2); for example, hydrolysates of starch-acrylonitrile graft copolymers, cellulose-acrylic acid copolymers and their salts; (6) and ( Copolymers with C) such as polyacrylamide crosslinked with a divinyl compound (methylenebisacrylamide etc.) and its partial hydrolyzate, crosslinked sulfonated polystyrene, crosslinked poval, JP-A-52-14689, JP-A-Sho. 52-27455
Examples include saponified crosslinked vinyl ester-unsaturated carboxylic acid copolymers and crosslinked polyethylene oxide described in each publication. Two or more of these water-absorbing resins may be used in combination.

Examples of the water-soluble polymer compound (b) include the following. For example, natural systems include starch, guar gum, and xanthan gum; semi-synthetic systems include methyl cellulose, hydroxyethyl cellulose, and carboxymethyl cellulose; synthetic systems include polymers and copolymers of water-soluble acrylic monomers and their alkali metal salts; Examples include polyvinyl alcohol and its derivatives, saponified products of vinyl acetate-acrylic acid ester copolymers, and polyethylene glycol and its derivatives having an average molecular weight of 500,000 or more. Preferred are hydroxyethylcellulose, sodium polyacrylate and xanthan gum, particularly hydroxyethylcellulose.

The inert organic liquid (c) may be either hydrophilic or hydrophobic as long as it is liquid at -10°C to 50°C, does not swell or dissolve the water-absorbing resin, and does not react with it. good. To give an example, examples of hydrophilic and weakly hydrophilic substances include polyethylene glycol,
polypropylene glycol, ethylene glycol, propylene glycol, guba ethylene glycol diacetate, ethylene glycol dimethyl ether, etc.), etc.
Examples of hydrophobic oils include rapeseed oil and mineral oil.

Preferably it is polyethylene glycol.

In the present invention, the total amount of pure water-insoluble water-absorbent resin (a) and water-soluble polymer compound (b) is (a), (b)
) and (c) based on the total weight of pure components, usually 5 to 6
5%, preferably 20-40%. If it is less than 5%, no effect of preventing slippage can be expected, and if it exceeds 65%, there is no fluidity and it is disadvantageous in terms of workability.

Here, the ratio of (a) and (b) is usually (a):
(b) = nio, 1-1:10. Preferably, (a
): (b) = nio, a~1:1.

When the ratio of (b) to (a) is less than 0.1, electrolyte resistance deteriorates, and when it exceeds 10, wall-building properties deteriorate, and in either case, it is difficult to expect mud slip prevention performance.

The pure content of the inert organic liquid (c) is usually 35 to 95%, preferably 45 to 35%, based on the total weight of the pure parts of (aλ(b) and (c)). Less than 35%, There was a problem in terms of workability due to the lack of fluidity of the anti-sludge agent, and 95%
If it exceeds this value, no effect on preventing lost mud can be expected.

The sludge prevention agent of the present invention is usually added to the ground or slurry material. The amount added depends on the target ground, water content of the slurry material, water pressure,
Although it varies depending on the required flow value of the excavated soil, etc., 0.5 to 1.5% of the water content is usually appropriate.

In an embodiment of preventing sludge loss while excavating the ground using the slurry shield method, first, the sludge prevention agent of the present invention is stirred and mixed in a tank or the like to form a slurry.

Next, this slurry is forced into the mix chamber through an emergency injection port of a shield machine using a pressure feeder such as a small gear pump. Alternatively, press it into the slurry pumping hose near the shield machine and inject it into the target soil. In this case, the sludge prevention agent instantaneously absorbs nearby water and swells into a gel, clogging the sludge area, stopping sludge sludge, and maintaining the pressure within the chamber.

The additive of the present invention contains (a), (b) and (C), and in addition, preservative M, = (a) (b) (
It is also possible to appropriately use 0 to 5% of a conventionally used anti-sludge agent, such as pulp-fed cotton seed residue, perlite, etc., in an amount of 0 to 5% based on the total weight of c).

〔Example〕

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited thereto.

Parts and percentages in the examples are by weight unless otherwise specified.

The test methods in Examples and Comparative Examples are as follows. In the Examples and Comparative Examples, the super absorbent resin used was Sunwet IM-1000 [Sanyo Chemical Industry ■], and the viscosity measurement after mixing with seawater was performed using artificial seawater.
Aquamarine Si (manufactured by Hesu Yakuhin ■) was used.

(1) After adding 1 part of sludge prevention agent to 100 parts of water absorption viscosity clean water, let it stand.
For the sample after one day, the viscosity at 20"C is B
Measured with a type viscometer. The unit is cps.

(2) Viscosity after mixing with seawater Add 1 part of artificial seawater Aquamarine SJ (25 times concentrated product) to 100 parts of the sample after measuring the water absorption viscosity above, mix thoroughly and leave to stand. Measure the viscosity at °C using a B-type viscometer.The unit is CPS.

(3) Viscosity after mixing cement To 100 parts of the sample after water viscosity measurement, add 3 parts of Portland cement, mix thoroughly, leave to stand, and after one day has passed,
Measure the viscosity at 20°C using a B-type viscometer. Unit is CP
S.

(4) Amount of water removed Using a filter according to API standards for the sample whose water absorption viscosity was measured, it was 8 kg/c! The compositions of the 8-part rear examples 1-3) and the comparative inhibitors (comparative examples 1-3) are shown in Table 1.

Table 1 (1) Table 1 (2) Table 2 Table 2 (continued) Example 4 and Comparative Example 4 The sludge prevention agents of Example 1 and Comparative Example 1 were used at a certain construction site in Shimo, Tokyo (50 m underground). Earth pressure balance shield construction site, target ± (gravel and silt layer) 7 moisture content approximately 60% (
seawater (approximately 80% mixed), groundwater pressure is approximately 8 kg/cd
), and the excellent sludge prevention properties of Example 1 were confirmed.

Result 1: Electrolyte resistance When approximately 1% of the anti-sludge agent of Example 1 was injected into the chamber using a small gear pump based on the target water, the pressure inside the chamber was maintained at approximately a kg/d, and shield propulsion was successful. Proceeded to.

Similarly, when the anti-sludge agent of Comparative Example 1 was injected, the pressure inside the chamber did not increase and shield propulsion was not possible.

2. Effect on preventing sludge loss When no sludge prevention agent was added, sludge was violently removed from the sludge pipe due to groundwater pressure, making it difficult to propel. When 1% of the sludge prevention agent of Example 1 was injected into the target water from the sludge removal inlet of the shield machine, sludge was easily removed from the sludge pipe, and continuous propulsion was possible. Further, no increase in agitator torque was observed.

Next, when the sludge prevention agent of Comparative Example 3 was injected under the same conditions, a large amount of sludge escaped from the sludge pipe, making continuous propulsion impossible.

〔Effect of the invention〕

The sludge prevention agent for shield construction method of the present invention has the following excellent effects.

1. Even if electrolytes such as seawater or cement are mixed in, the sludge prevention performance will not deteriorate.

2. It can be pumped using a small pump and does not require special machinery or equipment.

3. It instantly gels when it comes into contact with water, allowing you to repair lost mud in a short period of time.

4. It becomes highly viscous just by mixing a small amount in water, so the amount added can be small, making it economical.

5. Even if pressure is applied to the water-absorbing gel, there is almost no water separation, so it is excellent for pressure shield construction methods and as an anti-sludge agent for pressurized ground.

6. The water-absorbing gel has low adhesion (triaxial compressive strength===Okg weight/j), making it easy to excavate.

7. Because the water-absorbing gel exhibits high water-stopping properties, it can also be used for excavating ground with a high coefficient of permeability.

8. In the pH range of 4 to 10, its performance is
is hardly affected by.

9. Water-absorbing gel has lubricating properties, so it is effective in reducing friction between the ground and machinery.

10. Conventional sludge prevention agents, such as oil-highly absorbent sugar, /f fiber-based glutinous cotton seed dregs,
Shows better sludge prevention effect than pearlite, oil-bentonite, cement, etc.

Claims (1)

[Scope of Claims] 1. A sludge prevention agent for shield construction method, comprising a water-insoluble water-absorbing resin (a), a water-soluble polymer compound (b), and an inert organic liquid (c). 2. The total amount of pure components of (a) and (b) is 5 to 65% based on the total weight of pure components of (a), (b) and (c), according to claim 1. Inhibitor. 3. The prevention according to claim 1 or 2, wherein the pure content of (c) is 35 to 95% based on the total weight of pure parts of (a), (b), and (c). agent. 4. The ratio of (a) and (b) is (a):(b)=1:0
．． 1 to 1:10, the inhibitor according to any one of claims 1 to 3.