JPH0742147B2 - Method for producing cement / bentonite injection liquid and powder for producing the injection liquid - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a cement / bentonite injection liquid used in, for example, a pile construction method, an underground continuous wall construction method, a graft construction method, a CCP construction method, etc., and a powder for producing the same. .

[0002]

2. Description of the Related Art Conventionally, a cement / bentonite injection solution has been manufactured by a method in which bentonite is poured into fresh water, and after a predetermined time has elapsed, cement is added.

As an example, 25 kg of bentonite was charged into a mixer containing 450 liters of fresh water,
After about 30 to 60 seconds, 120 kg of cement
Add. As a result, an appropriate cement / bentonite injection liquid was manufactured as an injection liquid.

That is, the bentonite is sufficiently added to the bentonite by swelling the bentonite for a predetermined time.
Disperse and colloid. If you add cement there,
The metal ions generated during the hydration of cement are adsorbed on the surface of the bentonite particles, and the gelation reaction occurs throughout the liquid due to the electrochemical action, so that an injection liquid having a desired viscosity is manufactured.

[0005]

[Problems to be Solved by the Invention] However, if
With the same formulation as above, if cement is added first and bentonite is added later, bentonite swells, disperses, and in the process of colloidation, metal ions due to cement are adsorbed on the surface of bentonite particles, and subsequent swelling of bentonite. Is prevented, and only a liquid in which precipitation is generated can be obtained, and as a result, uniaxial compressive strength and other physical properties are adversely affected.

Bentonite comes first, then cement,
Even in the case of a proper charging sequence, when the time from charging the bentonite to charging the cement is short, swelling, dispersion, and colloidalization of the bentonite do not proceed sufficiently, and metal ions are present on the surface of the bentonite particles. As a result, the bentonite is adsorbed and the subsequent swelling of the bentonite is hindered, and a liquid having a precipitate is generated in the same manner as the above-mentioned case, and as a result, the uniaxial compression strength and other physical properties are adversely affected.

Therefore, in order to avoid such precipitation,
Workers at the site had to carefully consider the order of loading cement and bentonite and the time interval from the loading of bentonite to the loading of cement, and had to perform strict process control.

An object of the present invention is to solve the above-mentioned conventional problems and to facilitate the control of the liquid production process.

[0009]

In the above object, according to the Invention The, present invention is a weight ratio of 100: ratio of 40-300 to prepare a cement powder and bentonite powder, and water in both powder simultaneously 50-500 of total 100 The gist is a method for producing a cement-bentonite injection liquid, which is characterized by combined mixing.

Another invention is a powder for producing cement / bentonite injection liquid, which comprises a mixture of cement powder and bentonite powder in a weight ratio of 100: 40 to 300 as a main ingredient. Use as a summary.

As the cement powder, general one such as portland cement or mixed cement mainly composed of portland cement is used.

As the bentonite powder, a grayish white general powder containing a clay mineral montmorillonite as a main component is used.

As the water, fresh water may be used,
Seawater may be used.

Then, the bentonite powder is regulated within the range of 40 to 300 with respect to 100 of the cement powder, and this range allows the liquid to have a gelled proper viscosity without precipitation by adjusting the amount of water. If the amount is less than 40 , bentonite and cement will tend to precipitate, no matter how the amount of water is adjusted. If it exceeds 300, gelation will occur as a whole. However, excessive gelation adversely affects the uniaxial compressive stress and other physical property values, and causes a jelly-like property, resulting in poor suitability as an injection liquid.

A preferred mixing ratio of bentonite 40-80 relative to the cement 100, in particular 60 ± 5. In this way, by increasing the blending ratio of bentonite as compared with the conventional one, it is possible to obtain an injectable liquid having an excellent water blocking effect while maintaining a certain strength or more. In addition to fresh water, seawater can be used.

In the above manufacturing method, one or more kinds of thickeners, dispersants, and solidifying agents are used, and in the above-mentioned manufacturing powder, one or more kinds thereof are mixed. Is preferred.

As the thickener, for example, modified vinyl acetate type,
Powders that do not impair the hydration reaction of cement, such as vinyl acetate-beova group copolymers, vinyl acetate polymerization systems such as vinyl acetate-ethylene, and methyl cellulose, are preferably used. And the compounding ratio is 0.01 to 10.0 with respect to 100 of cement.
If it is less than 0.01, the thickening effect of the same agent is not exerted, and if it is more than 10.0, the cost is increased, and the solution becomes jelly and is not suitable as an injection solution. A preferred mixing ratio is 0.1 to 1.
It is 0.

As the dispersant, for example, powders such as lignin sulfonate and β-naphthalene sulfonate that do not impair the hydration reaction of cement are preferably used. And the mixing ratio is 0.01 to 100 with respect to the cement.
It is 10.0. When it is less than 0.01, the dispersing effect of the same agent is not exhibited, and when it is more than 10.0, the cost is increased and the effect is saturated.
A preferred blending ratio is 0.1 to 1.0.

As the solidifying agent, for example, powders such as slag and quicklime that do not impair the hydration reaction of cement are preferably used. The mixing ratio is 0.1 to 100 with respect to 100 of cement. If it is less than 0.1, the solidifying effect of the same agent is not exerted, and if it exceeds 100, it has an adverse effect such as abnormal setting of cement. A preferable blending ratio is 2 to 50.

In addition, sand may be used in the above-mentioned manufacturing method, and sand may be mixed in the above-mentioned manufacturing powder. The mixing ratio is 10 to 100 of cement.
~ 500. If it becomes smaller than 10, the improvement of uniaxial compressive strength due to the use of sand is not sufficient,
When it exceeds 0 and becomes large, cement hardly enters the gap between the sands, resulting in a problem that the uniaxial compressive strength is lowered. A preferred blending ratio is 100 to 300
Is.

Further, in the method for producing an injection liquid, the cement and the bentonite may be mixed with water, or the cement powder and the bentonite powder prepared separately may be simultaneously added to the water. Good. The same applies when one or more thickeners, dispersants, and solidifying agents are used.

When the weight of both the cement and bentonite powders is 100, the amount of water is regulated within the range of 50 to 500. Below 50, the hydration of the cement becomes insufficient and the strength deteriorates. At the same time, the swelling of bentonite is regulated, and if it exceeds 500 and becomes excessive, precipitation occurs. The suitable range of the amount of water is 100 to 30.
0, especially 150-250.

[0023]

In the above invention, bentonite within the above range,
Cement, bentonite under water formulation swelling, dispersion, and the progress of the colloid by gelation reaction due to adsorption of metal ions due Se <br/> instrument to such bentonite, also bentonite, cement In addition, due to the abrasion in the liquid due to the mixing of the liquid in which water is combined at the same time, an injection liquid having a good viscosity without precipitation is produced.

[0024]

As described above, according to the present invention, since it has the constitution as described above, the cement powder and the bentonite powder can be obtained.
There is no precipitation even if you mix and with water at the same time.
An injection liquid with a favorable viscosity can be obtained.Therefore, there is no need for detailed control such as the order of placing cement and bentonite and the time interval from the addition of bentonite to the addition of cement as in the past, which simplifies the production process control. Can be planned. Also, since cement and bentonite are basically added at the same time, the liquid production time can be shortened as compared with the conventional case.

[0025]

EXAMPLES Examples will be described below.

Example 1 A powder for production in which cement and bentonite were mixed and mixed in a weight ratio of 100: 60 was prepared, and 100 of this powder was mixed with 200 of clear water and mixed to produce an injection liquid. did. The resulting infusion solution gelled as a whole and the precipitation was negligible. The viscous state was also suitable as an injecting liquid. Further, the uniaxial compressive strength after consolidation was also sufficient.

Example 2 A powder for production was prepared in which cement and bentonite were mixed and mixed in a weight ratio of 100: 60. 100 of this powder was combined with 150 of seawater and mixed to produce an injection liquid. did. The resulting infusion solution gelled as a whole and the precipitation was negligible. The viscous state was also suitable as an injecting liquid. Further, the uniaxial compressive strength after consolidation was also sufficient.

Example 3 Cement, bentonite, thickener, and dispersant were mixed and mixed in a weight ratio of 100: 60: 0.7: 0.1 to prepare a manufacturing powder. When the combined amount was 100, 150 fresh water and the above-mentioned production powder were combined and mixed to produce an injection liquid. The resulting infusion solution gelled as a whole and the precipitation was negligible. The viscous state was also suitable as an injecting liquid. Further, the uniaxial compressive strength after consolidation was also sufficient.

Example 4 Cement, bentonite, and sand in a weight ratio of 100: 6
Prepare powder for production mixed and mixed at a ratio of 0: 100,
When the total amount of cement and bentonite was 100, 100 parts of fresh water was mixed with the above-mentioned production powder and mixed to prepare an injection liquid. The resulting infusion solution gelled as a whole and the precipitation was negligible. The viscous state was also suitable as an injecting liquid. The sand was finely divided and well dispersed. Further, the uniaxial compressive strength after consolidation was also sufficient.

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Claims (2)

[Claims] 1. A cement powder and a bentonite powder are prepared in a weight ratio of 100: 40 to 300, and a total of 100 is prepared.
A method for producing a cement-bentonite injection solution, which comprises simultaneously mixing both powders with 50-500 water and mixing. 2. A powder for producing a cement / bentonite injection solution, which comprises a mixture of cement powder and bentonite powder in a weight ratio of 100: 40 to 300 as a main ingredient.