JPH0672222B2 - Ground injection material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a ground injecting material using white carbon, which has a high consolidation strength and is particularly excellent in gel strength and durability of the consolidation. Ground injection material.

[Prior art and its problems]

Heretofore, an injection method using a water glass-reactant-silicic acid colloidal solution system has been known as in the prior application No. 59-172583 by the present applicant.

The silicic acid colloidal solution used in this injection method is a solution obtained by passing water glass through an ion-exchange resin to remove Na ions in the water glass and increasing the particle size of SiO ₂ to approximately 6 to 50 mμ to stabilize it. is there. This silicic acid colloidal solution suddenly reacts with polyvalent metal electrolytes such as cement and lime to gel into tofu, or slowly reacts with acid (several hours to several tens of hours). , The reactivity with the reactant is extremely high.

Therefore, in the above water glass-reactant-silicic acid colloidal grout, the pH of the injecting agent, the type of the reactive agent, and the content of the silicic acid colloid have a great influence on the gelation time.

However, originally, as for the ground injection material, selection of the reaction agent according to the ground (suspension property, solution property, etc.), selection of gel time according to construction conditions, and selection of strength according to the purpose should be done independently. is there. However, in the conventional injection method, it was difficult to select the most ideal one because these were related to each other.

[Object of the invention] The object of the present invention is to obtain a desired strength regardless of gelation time and selection of a reaction agent, and also excellent in caking strength, particularly excellent in gel strength, and further, durability of caking. It is also to provide an excellent ground injection.

[Main points of the invention]

In order to achieve the above-mentioned object, the present invention is characterized by comprising a ternary compound liquid of water glass, a reactant, and white carbon.

[Specific Description of the Invention]

The white carbon in the present invention is fine powder or ultrafine particles of anhydrous or hydrated silicic acid and silicate.

White carbon is generally classified into the following four types according to its composition.

1) Silicic anhydride (SiO ₂ ) SiO ₂ is about 98% or more, and the amount of attached water and bound water is extremely small. Although it contains a small amount of water, it is referred to as anhydrous silicic acid in contrast to the hydrous silicic acid of 2) below.

2) Hydrous silicic acid (SiO ₂ · nH ₂ O) SiO ₂ is also referred to as hydrated silicic acid, which has about 80 to 90% of SiO ₂ and a large amount of attached water and bound water.

3) Hydrous calcium silicate (xSiO ₂ · CaO · nH ₂ O) SiO ₂ is about 55 to 65% and is also called hydrated calcium silicate.

4) Hydrous aluminum silicate (xSiO ₂ · Al ₂ O ₃ · nH ₂ O) SiO ₂ is about 60 to 70% and is also called hydrated aluminum silicate.

Finely powdered aluminosilicate is also in this.

White carbon is manufactured as follows.

Dry method = A. Decomposition of organosilicon compounds B. Decomposition of silicon halides C. Decomposition of hydrosilicofluoric acid D. Heating of silica sand and coke mixture by arc Wet method = A. Decomposition of sodium silicate by acid B. C. Decomposition of sodium silicate by ammonium salt C. Decomposition of sodium silicate by ion exchange resin D. Decomposition of alkaline earth acid derived from sodium silicate E. Others Organogel method of making aerogel from organogel of silicic acid by autoclave PH of certain white carbon is silicic anhydride: 3 to 7, hydrous silicic acid: 5 to
11, hydrous calcium silicate: 9.5 to 10.5, hydrous aluminum silicate: 9.5 to 10.5.

The single particle diameter of white carbon is usually 10 to 100 μm, but these are lightly aggregated to form aggregated particles of about 1 to 5 μm. Further, there are also those having an average particle size of 1 to 100 μm.

The present inventor has noticed that when white carbon is used as an injecting material, the following characteristics of white carbon are extremely useful as an injecting material.

Small particle size and light weight.

(True specific gravity: Approx. 2.0 Apparent specific gravity: 0.15 to 0.35 g / cc) Large specific surface area (BET surface area: 50 to 300 m ² / g) Strong adsorption activity on the particle surface.

The particles make up the structure (mesh structure).

The structure of white carbon is measured by measuring the oil absorption amount, but the oil absorption amount can be about 120 to 280 cc / 100 g as an example.

That is, the water glass-reactant-white carbon system and the injecting solution were dispersed in the whole solution without forming white carbon to form a structure, and the silica component precipitated by the reaction of the water glass-reactant with time was removed. Adsorption on the structure and progress of gelation. Structuring imparts tensile stress to the gel and contributes to increasing hardness.

In addition, white carbon does not react rapidly with the reaction agent like silica in the silicic acid colloidal solution,
It has little effect on gelation time.

That is, even if a reactant is added to the colloidal solution in which white carbon is dispersed, gelation does not occur.

Therefore, in the water glass-reactant-white carbon system, even if the concentration of white carbon increases or decreases, the gelling time is hardly affected, but the strength increases, and the greater the concentration of white carbon, the greater the strength. When the reaction agent is lime or cement, white carbon has almost no effect on the gel time, but the gel strength is greatly increased by the formation of calcium silicate. In addition, the action of the structuring significantly reduces the shrinkage of the gel, and the leaching of SiO ₂ is greatly reduced, so that the water-stopping property and the solidifying property are not deteriorated and the durability is extremely improved.

It should be noted that hydrous calcium silicate and hydrous aluminum silicate as white carbon are different from calcium silicate that is usually used in the grout method. That is, the calcium silicate used in the grout is a powder of slag produced as a by-product during the production of pig iron, etc., which contains soluble silicic acid, lime, and magnesia, and is hardenable with lime. It quickly precipitates, does not disperse in water like white carbon to form a structure, has a small specific surface area,
It also has no adsorption activity.

This is because white carbon is OH on the inside and surface of hydrous silicic acid (hydrous calcium silicate, hydrous aluminum silicate) particles.
This is because there are many groups and they adsorb water by hydrogen bonding.

Therefore, in the present invention, white carbon is distinguished from ordinary calcium silicate and aluminum silicate.

Similarly, as SiO ₂ particles, there are fly ash, diatomaceous earth, silica fume sinters, and other posolane, which are mixed with water and left to stand.

That is, unlike white carbon, which has characteristics such as surface activity, surface adsorption, and apparent specific gravity, it cannot be dispersed throughout water like white carbon to form a structure. Therefore, it should be distinguished from the white carbon in the present invention.

Table 1 shows general examples of white carbon.

The present invention is shown below by experiments.

In this experiment, white carbon shown in Table 2 was used. (Shinogi Pharmaceutical Co., Ltd., Carplex) Experiment-1 Water glass-reactant system Water glass-reactant-silicic acid colloid system Water glass-reactant-white carbon system Comparative experiment was conducted, and the results are shown in Table-4. Table 3 shows the silicic acid colloidal solution used in the experiment.

The following can be seen from Table-4.

The strength of white carbon increases significantly depending on the amount added, regardless of the gelation time.

Compared to other systems, the water glass-reactant-white carbon system has a large strength despite its small total amount of SiO ₂ , and has excellent long-term strength, and also has a small amount of SiO ₂ leached. It is considered that this is because a dense gel is formed because water glass and the gel of the reaction agent are filled in the inside centering on the network structure of white carbon, the strength is high, and the leaching of SiO ₂ is reduced. Also, addition of white carbon reduces gel shrinkage. That is, when the reaction agent is water-soluble, the gel shrinkage after one week exhibits 20 VOL%, but when white carbon is contained, the gel shrinkage is suppressed within 5%.
This indicates that the watertightness is permanent, and that the solidity of the solidified material of the present invention is extremely great, including the phenomenon of increased long-term strength.

As the water glass in the present invention, any liquid or crystalline water glass having a molar ratio of 1.5 to 5.0 can be used.

Further, as the reaction agent, acid, salt, cement, lime, metal oxide, ester, glyoxal, other electrolytic substances, etc. can be used. Especially alkali metals, Ca, Mg, Al,
The polyvalent metal electrolytic substance such as cement becomes a reaction agent for water glass and is effective as a gelation accelerator for silicic acid colloid.

In actual injection, water glass, a reactant and white carbon may be mixed at the same time, white carbon may be mixed in a mixture of water glass and a reactant, water glass liquid and white carbon You may combine and mix the liquid mixture of a reactant.

Next, a specific example of the present invention for obtaining high strength with a long gelation time will be described.

It is water glass, white carbon, lime type, and is a method in which the SiO ₂ / Me ₂ O of water glass is 2.5 or less in molar ratio.

Furthermore, in the above method, the content of limes is lime / SiO.
_It is preferable that the molar ratio of ₂ is 2.0 or more. However, SiO ₂ is due to water glass and white carbon.

Conventional water glass grouts cannot achieve high strength by increasing the concentration of water glass with a long gelation time, and the durability of the solidified material, that is, the long-term solidified strength cannot be obtained. The reason for this is that if the gelation time is lengthened, the amount of the reactant is reduced, and it is not possible to react with the silica content of the water glass, and the main component of the solidified product is only silica derived from the water glass. Since this water glass is an almost complete solution, the molecular weight of the silica component contained in the water glass is extremely small, and the resulting gel also contains a large amount of unstable silica component. This is because the silica content elutes from the solidified material and the long-term strength decreases.

Therefore, in the present invention, in addition to water glass as a silica component, white carbon is further used, and SiO ₂ / M of water glass is used.
The molar ratio of e ₂ O is set to 2.5 or less, which not only stabilizes the solidified substance of silica and exhibits high solidification strength, but also increases the solidification strength for a long period of time and further improves the permeability. Further, it also facilitates the adjustment of the gelation time, in particular, the gelation time is adjusted to be long to obtain a high consolidation strength, and to provide a consolidation material in which the above-mentioned drawbacks in the known art are improved. .

Lime used in the present invention is quick lime, slaked lime, limestone,
It is a natural calcium compound powder such as dolomite, or a synthetic calcium compound powder of these main components, and of these, quick lime and slaked lime are particularly preferable. The amount used is preferably 0.2 or more in terms of molar ratio with respect to the total amount of water glass and silica due to white carbon in the mixed system, that is, the amount of limes / SiO ₂ is 0.2 or more in terms of molar ratio.

In addition to soil injection, the above-mentioned consolidation material of the present invention is mixed with soil or sand, stirred, sprayed on soil, or replaced with soil to construct a soil structure or the structure itself. Is also used. In particular, the present invention is extremely excellent in improving soil such as organic soil which has not been conventionally obtained with cement or lime.

Usually, when limes are added to water glass having a molar ratio of 2.5 or more, gelation occurs in a few seconds, and it is impossible to extend the gelation time of tens of minutes or 60 minutes or more.

However, when the silica content from white carbon is used together with water glass of 2.5 or less, the gelation time becomes long and the gelation product becomes strong even though the silica content has the same concentration.

When white carbon is mixed with a low-alkali water glass aqueous solution with a molar ratio of 2.5 or less at room temperature, part of it is dissolved by the alkali, and the silica dissolved around it and the silica in the water glass are suspended. It shows a turbid state, and white carbon forms a structure throughout the liquid. It is presumed that this is because the specific surface area of white carbon is very large and the surface of the white carbon has excellent surface activity due to the action of alkali. Therefore, if limes are present here, a strong net is formed by precipitating calcium silicate around the structure, and as a result of filling the inside with calcium silicate due to the reaction between the silica content of water glass and lime, a strong net is formed. A solid is formed.
Further, since limes are poorly soluble powders, the gelation time is not shortened even if a sufficient amount is added, and Ca ⁺⁺ is supplied to white carbon for a long period of time to develop long-term strength.

It should be noted that the mixed liquid of white carbon and limes hardly reacts even when left standing, and therefore does not gel. And the entire formulation solution without first precipitated with long gel times in the conditions homogeneously consolidated, its consolidated was gel strength is very large, and no shrinkage, further SiO ₂
There is almost no leaching and the long-term strength is extremely high, so a solidified product with excellent durability is obtained.

[Experiment-2] Commercially available No. 3 water glass (molar ratio 2.94, SiO ₂ : 28.29%, Na ₂ O:
9.94%, specific gravity 1.4 manufactured by the melting method) and slaked lime gelation time were measured, and the results are shown in Table-5.

From Table-5, it can be seen that in No. 3 water glass, the gelation time is short with any amount of Ca (OH) ₂ . Further, the strength is also small, for example, in the case of sample No. 3, the consolidated standard sand, after 30 days, 1.
5kg / cm ^{2 About} 0.8kg / cm ² after 1 month underwater curing.

[Experiment-3] White carbon and SiO ₂ / Na ₂ O (molar ratio) 2.0 commercially available water glass were added with slaked lime in an amount of CaO / SiO ₂ (molar ratio) 1.0, and the gelation time for each compounded solution Also, the caking strength was measured. The results are shown in Table-6.

From Table-6, when the SiO ₂ concentration is increased, only water glass
It can be seen that while depending on SiO ₂ , the gelling time becomes short, but when depending also on SiO ₂ from white carbon, the gelling time becomes long.

Also, it can be seen that SiO ₂ has an excellent effect only when it depends on both water glass and white carbon, and that white carbon has a significantly higher consolidation strength than fly ash, which is a posolan. This seems to be due to the adsorptivity of white carbon and the effect of the structure.

[Experiment-4] The SiO ₂ / Na ₂ O (molar ratio) was changed, and the gelation time and the caking strength of these were measured, and the results are shown in Table 7. The silica content was 0.1 mol from water glass and 0.1 mol from white carbon per 100 cc of the blended liquid, and the total was 0.2 mol.

From Table 7, it can be seen that long-term strength and long gelation time are obtained when the SiO ₂ / Na ₂ O molar ratio is 2.5 or less.

In the same manner as Experiment -5] Experiment -4, CaO / SiO ₂ (molar ratio) is changed, the caking strength for these measures, the results are shown in Table 8.

Here, SiO ₂ / Na ₂ O (mole ratio) was 1.5.

From Table-8, it can be seen that the CaO / SiO ₂ molar ratio of 0.2 or more is desirable because it exhibits high consolidation strength.

In the same manner as Experiment -6] Experiment -4, molar ratio of CaO / SiO ₂ is 1.0, SiO ₂ /
The Na ₂ O molar ratio was 2.0 and the SiO ₂ concentration was changed, and the gelation time and the caking strength were measured for each, and the results are shown in Table-9.

From Table 9, it can be seen that if the SiO ₂ concentration is 0.10 mol or more per 100 cc of the blended liquid, high consolidation strength is obtained, which is desirable.

In the present invention, various kinds of reactants can be used together, silicic acid colloid can be used together to shorten the gelation time, and slag or pozzolan can also be used together.

〔The invention's effect〕

As described above, the caking material according to the present invention is a caking material most suitable as a chemical solution for ground caking, as well as obtaining caking strength even if the gelation time is lengthened, and having excellent long-term durability. .

Claims (1)

[Claims] 1. A ground injecting material comprising a ternary compound liquid of water glass, a reaction agent and white carbon.