JPH0517761A - Stabilizer for regulating muddy water - Google Patents

Abstract

PURPOSE:To obtain a stabilizer for regulating muddy water containing an alkali phosphate and an alkali carbonate as an active component, useful for ground boring, slurry shield methods, etc., and capable of stably holding the muddy water even if cement or seawater is present in the muddy water. CONSTITUTION:A stabilizer for regulating muddy water containing an alkali phosphate (preferably sodium orthophosphate or sodium polyphosphate) and an alkali carbonate (preferably sodium carbonate) as an active ingredient. The alkali phosphate and the alkali carbonate are normally used at (1:5) to (5:1) weight ratio. The aforementioned stabilizer is preferably used in an amount of 30-40wt.% based on the cement component in the muddy water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stabilizer for adjusting muddy water during ground excavation. Furthermore, the cast-in-place pile method,
The present invention relates to an additive for stabilizing muddy water used in ground boring, muddy water shield construction method and underground continuous wall construction method.

[0002]

2. Description of the Related Art It is well known that a mud shield method has been used for ground excavation in underground civil engineering works such as subway construction. Various additives for adjusting stable mud are known as mud used in such an excavation method. For example, thickeners such as bentonite and CMC (carboxymethyl cellulose), alkali polyphosphates such as sodium hexametaphosphate and sodium tripolyphosphate, dispersants such as sodium ligninsulfonate, sodium nitrohumate or sodium polyacrylate, salicylic acid and sorbic acid. Organic alteration inhibitors such as the above are used.

Due to the diversity of mud water, one kind of such mud water control additive cannot be used, and in many cases, several kinds of additives are prepared and used according to the physical properties of the mud water (for example,
JP-A-56-18683, JP-A-56-84785, JP-B-60-58274, etc.).

[0004]

However, conventional mud water regulators are not satisfactory for stabilizing mud water, and their application range is extremely limited. When a large amount of calcium ions and magnesium ions are mixed in the muddy water, cement components are inevitably mixed, or where seawater is mixed, the performance of conventional muddy water regulators is significantly degraded, and the muddy water gels, Breathing or dehydration to the ground often causes construction troubles such as collapse of the excavated wall surface, making mud transportation difficult, and reducing mud treatment efficiency.

Under these circumstances, there is a demand for the development of an inexpensive stabilizer for adjusting muddy water, which imparts the cement and seawater resistance to muddy water.

The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a muddy water adjusting stabilizer capable of retaining stable muddy water even when cement or seawater is present in the muddy water. It is intended.

[0007]

That is, the stabilizing agent for adjusting muddy water, which is to be provided by the present invention, is characterized in that it contains alkali phosphate and alkali carbonate as active ingredients.

In the present invention, the alkali phosphate means an alkali orthophosphate and / or an alkali polyphosphate, and examples thereof include sodium or potassium monohydrogen phosphate alkali, dihydrogen phosphate alkali, alkali orthophosphate, and acid. Examples thereof include alkali pyrophosphate, alkali pyrophosphate, tripolyphosphate alkali and hexametaphosphate, with sodium orthophosphate or sodium polyphosphate being particularly preferable.

The alkali carbonate may be sodium carbonate, potassium carbonate, sodium bicarbonate or potassium bicarbonate, with sodium carbonate being preferred.

The stabilizer for adjusting muddy water according to the present invention contains alkali phosphate and alkali carbonate as active ingredients as described above, and if necessary, for example, CMC, starch,
A water-soluble polymer such as dextrin, sodium alginate, polyacrylamide, sodium polyacrylate, or polyethylene oxide, a thickener such as bentonite, a dispersant, or a chelating agent can be used in combination.

Of the above additives, polyanionic cellulose can be preferably used as a salt-resistant thickener.

The use ratio of alkali phosphate and alkali carbonate relating to the above-mentioned stabilizer for adjusting muddy water varies depending on the kind of chemicals, the characteristics of muddy water, the conditions of the construction method, etc. Alkali: Alkali carbonate = 1: 5 to 5: 1, and the amount of the stabilizer used is 25 to 65% by weight, preferably 30 to 40% by weight for the cement component in the muddy water. is there. Further, other auxiliary additive components are in the range of 0 to 5% by weight, preferably 0 to 2% by weight, based on the solid content of muddy water (dry basis).

[0013]

The stabilizing agent for adjusting muddy water according to the present invention stabilizes muddy water, but the details of the mechanism of action are unknown, but with alkali phosphate or alkali carbonate alone,
Since the stabilization of mud cannot be achieved, it is clear that it is based on the synergistic action of the two agents.

That is, a large amount of calcium ions from cement or excavated soil is fixed as insoluble calcium carbonate by alkali carbonate, and the dispersing action of muddy water of alkali phosphate is combined with its chelating action.
It is presumed that this will stabilize the muddy water.

[0015]

EXAMPLES The present invention will be specifically described with reference to Examples and Comparative Examples. The "parts" and "%" in the examples and comparative examples are by weight.

Test method for muddy water 1) Funnel viscosity: A sample muddy water of 500 ml A at room temperature
Measured with a PI (American Petroleum Institute) standard funnel viscometer. 2) Dehydration amount: The sampled muddy water was filtered with an API-standard pressure filtration tester at a pressure of 3 kg / cm ² for 30 minutes to obtain a filtration amount of ml.
Indicate. 3) Breathing rate: Sample mud water is filled in a graduated cylinder of 1000 ml, left standing for 20 hours, and the amount of the supernatant is measured, which is shown as a percentage of the total volume.

Evaluation method of muddy water The stability of muddy water is comprehensively evaluated by a four-step method from the funnel viscosity of mud water, the amount of dehydration, the breathing rate, and the appearance. Good stability: ○ Poor muddy water stability: △ Poor muddy water stability, gelation that can not be measured by testing ・ ・ ・ ×

Preparation of sample muddy water Sample muddy water is prepared by mixing predetermined amounts of the following clay, water-soluble polymer, alkali phosphate and alkali carbonate.
A predetermined amount of cement and artificial seawater was added thereto, and the stability of mud water was evaluated. The results shown in Tables 1 and 2 were obtained.

The following main raw materials were used. 1) clay Clay symbol AC-1 Japan Unified Soil Classification Clay (CH) Particle size characteristics Gravel 1% Sand content 16% Silt amount 49% Clay content 34% Moisture content 95.8%

2) Cement Chichibu Cement Co., Ltd .: Ordinary Portland Cement

3) Artificial seawater Yasu Pharmaceutical Co., Ltd .: Trade name Aquamarine Main ingredients (powder) Sodium chloride 57.94% Magnesium chloride (hexahydrate) 26.24% Sodium sulfate (anhydrous) 9.67% Potassium chloride 1.64%

4) Alkaline Phosphate Alkaline phosphates manufactured by Nippon Kagaku Kogyo Co., Ltd. Sodium monophosphate (anhydrous) Sodium diphosphate (anhydrous) Sodium triphosphate (anhydrous) Sodium tripolyphosphate Sodium hexametaphosphate Sodium pyrophosphate (Anhydrous) Anhydrous) Potassium monophosphate Potassium disulfate Potassium tertiary sulfate Potassium pyrophosphate

5) Sodium carbonate Junsei Kagaku Co., Ltd .: First-class reagents

6) Thickener (water-soluble polymer) manufactured by Daicel Chemical Industries, Ltd .: trade name Cellbase Mud RS
-25 The composition is a water-soluble polymer based on cellulose (polyanionic cellulose) Viscosity 200-300 cps 25 ° C 1% aqueous solution pH 10-12 1% aqueous solution

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

The stabilizer for adjusting muddy water of the present invention comprises alkali phosphate and alkali carbonate as active ingredients,
Immobilize a large amount of calcium and magnesium ions mixed in muddy water with alkali carbonate as an insoluble carbonate, and stabilize the muddy water by combining the dispersing action of alkaline phosphate with its chelating action. In the civil engineering industry, it can be effectively used for ground excavation and the like.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshinari Fujino             2-27-1, Nakanogawa-cho, Toyokawa-shi, Aichi High             Riverside 3-A (72) Inventor Tatsuji Maemura             3-115 Suwa, Toyokawa City, Aichi Prefecture 403 Suwa Dormitory (72) Inventor Hideaki Baba             9-15 Kameido, Koto-ku, Tokyo Japanization             Gaku Kogyo Co., Ltd. (72) Inventor Kuniaki Maejima             9-15 Kameido, Koto-ku, Tokyo Japanization             Gaku Kogyo Co., Ltd. (72) Inventor Sonobe Shigeru             9-15 Kameido, Koto-ku, Tokyo Japanization             Gaku Kogyo Co., Ltd.

Claims (4)

[Claims] 1. A stabilizer for adjusting mud water, which comprises alkali phosphate and alkali carbonate as active ingredients. 2. The stabilizer for adjusting muddy water according to claim 1, wherein the weight ratio of alkali phosphate: alkali carbonate is in the range of 5: 1 to 1: 5. 3. A stabilizer for adjusting mud water, which comprises an alkali phosphate, an alkali carbonate and a water-soluble polymer as active ingredients. 4. A mud-stabilizing composition comprising an alkaline phosphate, an alkaline carbonate, a water-soluble polymer and clay suspended therein.