JPS5880374A - Technique for digging the ground with muddy water - Google Patents

Abstract

PURPOSE:To dig the ground while preventing muddy water from being leaked through gaps in the ground, by digging the ground in the presence of muddy water for digging, which contains a powdered composite composed of a highly water-absorbing resin and an inorg. matter added thereto. CONSTITUTION:A particulate inorg. matter having a specific gravity of 1.50 or above such as quartz sand is added to a soln. contg. a highly water-absorbing resin such as an isobutylene/maleic anhydride copolymer. Said inog. matter is used in an amount of 0.1-10 times by weight that of said resin. The mixture is molded into a film or a fiber which is then dried and crushed. The crushed product is crosslinked to obtain a powdered composite which has a specific gravity of 1.01-1.15 after water absorption and can retain a state where the composite absobs water in an amount of at least 10 times by weight the own weight of the composite and is swollen without being dissolved. Then the ground is dug in the presence of muddy water for digging, which contains said composite. EFFECT:The swollen composite is stably floated on muddy water. When the removal of mud is started, fine gaps are filled with the swollen composite particles, and a mud cake of still water is formed thereon, whereby mud is prevented from escaping.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of excavating the ground using muddy water. More specifically, a muddy water excavation method for the ground is characterized in that a powdered composite consisting of a super absorbent resin and an inorganic substance is added to muddy water containing bentonite, etc. used in the ground excavation method. The present invention relates to a muddy water excavation method for the ground, which allows excavation to be carried out while preventing muddy water from leaking into the ground gap.

Ground excavation methods that use muddy water include the continuous underground wall method, various pile methods, and muddy water pressure shield method, all of which utilize the mud cake-forming ability of the muddy water components to prevent collapse of the excavated walls and face. It is something. This muddy water is made by suspending or dissolving bentonite, natural or synthetic water-soluble polymers, and clay such as china clay alone or in combination in water. The muddy water is managed to have good fluidity, with a viscosity of 5 to 50 centimeters and a specific gravity of around 1.0, considering the convenience of supply and collection as well as the subsequent process of concrete pouring. Ru. For this reason, when the soil quality of the ground to be excavated is sand and gravel or there are cracks in the strata, a large amount of muddy water infiltrates and deviates into the surrounding ground, resulting in so-called slippage. If the mud water pressure at the excavation #I or the face decreases due to lost mud, the excavation will collapse and the surrounding groundwater will be polluted.
In method 1, prevention of slippage is essential, and various countermeasures have been devised.

The present invention relates to the use of muddy water to which a powdered composite consisting of a superabsorbent resin and an inorganic substance is added as an anti-sludge material.

Conventionally, materials used as prevention materials include sawdust, cotton berries, bulbs, clickil, mica, etc., but due to the scale of the mud, the large size of the gap in the ground, the use of The type of materials to be used and the concentration of additives are determined by taking into account the type of muddy water. All of these materials had the disadvantage that they were difficult to stably disperse in muddy water because of the large difference in specific gravity between them and muddy water.

The present inventors have arrived at the present invention as a result of an intensive search for a material that satisfies the various properties required for a mud slip prevention material, such as stable dispersibility in muddy water and particle shape retention. The powder composite composed of a super absorbent resin and an inorganic substance used in the present invention absorbs at least 10 times its own weight of water, and maintains its own shape in a moist state without dissolving. Furthermore, the specific gravity of the composite when swollen after absorbing water was made to be approximately equal to the specific gravity of muddy water, ranging from 1.01 to 1.15. Therefore, the swollen composite particles stably float in muddy water without floating, and -
When sludge begins, the swollen composite particles quickly
It fills the side gaps that cause mud loss, and forms a water-stopping mud cake on top of it, which prevents mud loss.

Preferred examples of the powder composite of the superabsorbent resin and inorganic substance that can be used in the present invention include those in which the entire surface of the inorganic powder is covered with the superabsorbent resin. There are things that can be mentioned.

(1) An α-olefin such as ethylene, propylene, butene-1, isobutylene or diisobutylene, preferably an α-olefin having 2 to 12 carbon atoms, and maleic anhydride or its derivatives (e.g. maleic acid amide, Inorganic powders with a specific gravity of 1.50 or more, such as swellable and non-swellable clays such as pecytonite and kaolinite, and quartz sand, are added to an aqueous solution of a copolymer with maleic acid imide) or its alkali neutralized product. ! After adding a bridge or two or more fences 0.1 to 10 times the weight of the resin, once molded into a film or fiber or other shape, dried, and then crosslinked in the state of the molded product, The product is pulverized to an appropriate particle size, or the molded product is pulverized to an appropriate particle size and then crosslinked.

(2) The inorganic powder is added to an aqueous solution of a copolymer of a polymerizable vinyl compound such as methyl vinyl ether, vinyl acetate, or styrene and maleic anhydride or its derivative, or an alkali neutralized product thereof, and the weight of the resin is After adding 0.1 to 10 times the amount, mold it into a film or fiber or other shape, dry it, crosslink it in the state of the molded product, and then grind it to an appropriate particle size or After pulverizing the material to an appropriate particle size, it is cross-linked.

(3) Adding the above-mentioned inorganic powder to a self-crosslinking type alkali metal acrylate obtained from an alkali metal acrylate or an alkali metal methacrylate in an amount Ll of 1 to 10 times the weight of the unsaturated monomer. A powdered composite made by cross-linking polymerization.

(4) Add the inorganic powder to 0% of the weight of the organic matter in a solution of water or a mixed solvent of water and a hydrophilic organic solvent, which is a product obtained by graft polymerizing acrylic acid, acrylonitrile, maleic anhydride, etc. to starch or cellulose. - A powdered composite obtained by crosslinking after addition of 1 to 10 times.

Among these, powdered composites made using the maleic anhydride copolymers of (1) and (2) above, and powdered composites made of the self-crosslinking type acrylic acid alkali metal salts of (3). However, it is desirable because it is not subject to decomposition by microorganisms. Above all, from the viewpoint of the durability of the superabsorbent resin in a hydrated state, the α-olefin (especially imbutylene) - maleic anhydride copolymer - inorganic substance - polyvalent amine (
A powdered composite obtained by crosslinking (preethyleneimine) is effective in preventing slippage.

In the present invention, the particle size of the powdered composite made of super absorbent resin and inorganic substance used can be changed arbitrarily after water absorption and swelling by adjusting the particle size before water absorption. Depending on the properties, it is possible to select a composite with a particle size necessary to prevent slippage.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples in any way.

Example (1) Super absorbent resin used in this example
Manufacture of inorganic powder composites.

Isobutylene-maleic anhydride copolymer (an alternating copolymer of isobutylene and maleic anhydride in a molar ratio of 1:1, with a molecular weight of about 1.60000°, Isotwin-10 from Clarei Sobrene Chemical Company Il) 100 parts by weight, 52 parts by weight of sodium hydroxide (an amount equivalent to converting about 60 mol% of the carboxyl groups based on maleic anhydride in the copolymer into salts) and 500 parts by weight of water were stirred at a humidity of ao''c. A homogeneous aqueous solution of the sodium salt of isobutylene-maleic anhydride copolymer was then prepared.Then, this aqueous solution had a water absorption capacity of 1 after drying and heat treatment per super absorbent resin.
Polyethyleneimine having a molecular weight of 1200 (Polyethyleneimine 8F-012 manufactured by Nippon Shokubai Co., Ltd.) was added so as to increase the amount by 40 times. Kaolin clay (NN kaolin manufactured by Tsuchiya Chikara-Olin Kogyo Co., Ltd.) was added to this aqueous solution with a purity of 10% of the copolymer.
0 parts by weight to 300 parts by weight, about 12 parts by weight.
After drying on an iron plate at 0°C, it was further heat-treated in a hot air dryer at 160@0 for 16 hours. Shatter yourself 20
A highly water-absorbent powder composite was obtained as particles of mesh wire mesh. Put 1 g of this complex into 14 beakers,
000 g of distilled water was added and allowed to stand for 2 hours, after which the dispersion was filtered through a 200 mesh nylon cloth. The weight of the ice-containing composite thus obtained was measured, and the water absorption capacity of the composite was determined to be 4.
It was 5 times more. Further, the specific gravity of the composite when swollen by water absorption was 1.05.

(2) Preparation of drilling mud 2% by weight of bentonite, 0 carboxymethyl cellulose
．． The powdered composite obtained in (1) was added to muddy water containing 5% by weight.
．． Drilling mud was prepared by adding 1% by weight.

The injected powdered composite was stably floating in the muddy water without rising to the surface.

(3) Sludge prevention test in ground excavation First, drilling mud to which no superabsorbent resin-inorganic powder composite has been added (contains only 23111% bentonite and 0.5% carboxy'methyl cellulose) was introduced into the excavation site, and while excavating the ground using a Kerato-type excavator, the status of lost mud was checked by looking at the change (decrease) in the amount of mud water over time. In areas where sand and gravel layers were distributed, muddy water was observed to decrease at a rate of 15 m/hour, and severe mud slippage was observed.

On the other hand, the same operation as above was carried out using the drilling mud prepared in (S) (i.e., containing 0.1% by weight of a super absorbent resin-inorganic powder composite) to check the mud loss situation. When we checked, it was found that at the initial point when the excavation progressed into the gravel layer mentioned above, it was 0 Am" per hour, and after that it gradually decreased until it finally reached a steady state of about 0.18 m per hour, which is essentially It was observed that slippage was prevented.

As a result of further excavation, there was a gravel layer extending from 1-22 Peng to 35 meters, where the mud was slipping at a rate of 2.0 to 2.2 m per hour. It was confirmed that the amount of lost sludge could be suppressed to 0.18 to ◎, S- per hour.

Patent applicant: Obayashi Corporation Same as above RiRashi Co., Ltd. Representative Patent Attorney Ken Honda

Claims (1)

[Scope of Claims] (1) A ground mud Jllll I method, which is characterized in that the ground is excavated in the presence of drilling mud to which a powdered composite consisting of a superabsorbent resin and an inorganic substance is added. (2) The ground according to claim 1, wherein the powder composite consisting of a highly water-absorbent resin and an inorganic substance is formed by covering the entire surface of the inorganic powder with a high-grade water-based resin. mud excavation method. (5) A patent for a powdered composite consisting of a super absorbent resin and an inorganic substance that can absorb at least 10 times its own weight in water and maintain its own shape in a swollen state without dissolving. The ground mud excavation method according to claim 1. (4) The muddy water on the ground according to claim 1, which is a powdery composite made of a super absorbent resin and an inorganic material, which has a specific gravity in the range of 1.01 to 1.15 after water absorption. Excavation method.