JP3025957B2 - Chemical liquid for ground injection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of forming fine calcium hydroxide or cement having a specific particle size, which is hardly soluble in water but easily soluble in the presence of alkali, and water glass having a specific molar ratio. The present invention relates to a soil injection chemical solution as a main material, and more particularly to a permeable soil injection chemical solution suitable for injection into a permeable ground such as sandy soil.

[0002]

2. Description of the Related Art Conventionally, a water glass / slaked lime (calcium hydroxide) -based chemical is known as a solution-type ground injection chemical using a poorly soluble calcium compound.

[0003] Although this chemical solution contains a sparingly soluble calcium compound, its solubility increases in the presence of alkaline water glass, so that the gelation time can be shortened and a relatively high consolidation strength is obtained. It is a solution type chemical for ground injection to be presented.

However, in this system, in order to increase the solubility of slaked lime, water glass having a small molar ratio of SiO ₂ / Na ₂ O or calcium hydroxide having an average particle size of about 2.8 μm is used. Therefore, it has the following disadvantages.

[0005]

That is, in the above-mentioned known water glass-slaked lime (calcium hydroxide) -based chemical solution, when a water glass having a SiO ₂ / Na ₂ O molar ratio of 2.2 or less is used, Alkali content released by the reaction of calcium hydroxide and water glass elutes from the solidified matter,
Concerns about alkaline pollution arise.

When No. 3 water glass is used as the water glass and calcium hydroxide having an average particle size of about several microns is used, the calcium hydroxide has few particles having an average particle size of 1 micron or less. The effect of the residual particulate calcium hydroxide without dissolution is great. That is,
The gelation time is significantly different between the case where the particles are present in the mixture and the case where the sand is clogged and separated, and the clogging deteriorates the permeability of the chemical solution.

Therefore, an object of the present invention is to dissolve most of the reactant in a liquid for ground injection containing water glass and particulate calcium hydroxide and / or particulate cement as a reactant, as described above. It is an object of the present invention to provide a permeable ground injection chemical solution which ameliorates the disadvantages of the art.

[0008]

According to the present invention, in order to attain the above object, according to the present invention, in a ground injection chemical solution containing water glass and a reactant as main materials, the water glass has a molar ratio (SiO 2). ₂ / Na ₂ O) 2.8 or more, wherein the reactant is particulate calcium hydroxide, and the following requirements (1) to (3): (1) the average particle size is 2 microns or less I der, 0.5 micro
Not more than 10% by weight . (2) 80% by weight or more containing 2.5 microns or less in particle size . (3) A particle size of 3.5 microns or more is 10% by weight or less . And, if necessary, a particulate cement as a reactant.

Further, in order to achieve the above object, according to the present invention, in a ground injection chemical solution containing water glass and a reactant as main materials, the water glass has a molar ratio (S
iO ₂ / Na ₂ O) 2.8 or more, and the reactant has an average particle size of 2 μm or less and 0.5 μm or less of 10
It is a fine particle cement of not more than% by weight , and further contains fine particle calcium hydroxide as a reactant as required.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The chemical solution for injecting ground into the ground of the present invention basically comprises two types of systems: (A) water glass-fine particle calcium hydroxide system and (B) water glass-fine particle cement system. Hereinafter, each system of (A) and (B) will be specifically described in detail.

(A) Water glass-fine particle calcium hydroxide system. The chemical liquid for ground injection of this system according to the present invention is a chemical liquid containing water glass and a reactant as main components, and has a water glass having a molar ratio (SiO ₂ / Na ₂ O) of 2.8 or more. Glass, for example, No. 3 water glass is used, and fine particle calcium hydroxide having the following requirements (1) to (3) is used as a reactant.

(1) The average particle size is 2 microns or less. (2) 80% by weight or more of particles having a particle size of 2.5 microns or less. (3) The particle size of 3.5 microns or more is 10% by weight or less.

Most of such fine particles of calcium hydroxide are dissolved in water glass having a molar ratio of 2.8 or more, and become a ground injection chemical having the same permeability as a solution type injection material.

The amount of the fine particle calcium hydroxide to be used is 0.5 to 40 kg per 1 m ^{3 of the} ground liquid, and 2 to 100 kg per 1 m ^{3 of} water glass. The amount of the fine calcium hydroxide used need not be an amount that completely dissolves in the presence of water glass. That is, since this calcium hydroxide is a fine particle calcium hydroxide having an average particle diameter of 2 μm or less, gelation is sure even in a small amount. In particular, when the injection ground is sandy soil and there is no problem in permeability, even if there are particles that are not dissolved at the time of injection, they gradually dissolve and contribute to the strength and durability of the gel. Incidentally, the amount of water glass in the system ground injection drug solution 1 m ³ per a 200～700L.

The above-mentioned fine particle calcium hydroxide preferably has an average particle size of 1.5 μm or less, particularly preferably 1.0 μm or less. In this case, since the particle size of the calcium hydroxide is small, the solubility is large, and most of the calcium hydroxide is dissolved in about 2 to 3 seconds, so that the action as a hardening agent appears remarkably.

However, it is preferable that the particle size of 0.5 micron or less is 10% by weight or less. If the particle size is less than 0.5 microns, the gelation time will be too short if the amount of the particles used is large or if the temperature of the mixture is high.
If the amount of calcium hydroxide used is reduced in order to lengthen the gelation time, the strength of the consolidated product is undesirably reduced.
% Is preferable.

Further, in the system (A) according to the present invention, fine particles cement or fine particles slag can be used in addition to the above fine particles of calcium hydroxide as a reactant. It becomes strong.

In this case, the particle size of the fine particle cement does not need to be specified as in the case of the fine particle cement used in the system (B) described later, but is preferably a fine particle cement having an average particle size of 5 μm or less. . Such fine particle cement is used in combination when the fine particle calcium hydroxide has a small particle diameter and the gelation time is too short. The amount used is such that the mixing ratio of the fine particle calcium hydroxide and the fine particle cement is 90 to 5:10 to 95 by weight.

The particle size of the fine particle slag is not particularly specified if it is a fine particle, but is preferably 4 μm or less in average particle size. This fine particle slag exerts strength by the stimulation of alkali, and especially in this system, even when it is not possible to use a large amount of fine particle calcium hydroxide due to a short gelation time, if this fine particle slag is used in combination, fine particle calcium hydroxide can be used. To obtain a high-strength solidified product by hardening together with fine particle cement. In this case, in order to use fine particles having an average particle size of 2 microns or less for calcium hydroxide,
Even if the amount of calcium hydroxide used is 3.5% or less, the strength is sufficiently increased.

(B) Water glass-fine particle cement system. The chemical liquid for ground injection of this system according to the present invention is also a chemical liquid containing water glass and a reactant as main materials, and has a molar ratio (SiO ₂ / Na ₂ O) as water glass as described above.
Water glass of 2.8 or more, for example, No. 3 water glass, etc. is used, and as a reactant, fine particle cement having an average particle size of 2 μm or less is used.

Such a fine particle cement is also dissolved in water glass having a molar ratio of 2.8 or more to be a ground injection chemical having the same permeability as a solution type injection material.

The fine particle cement is industrially obtained as an ultrafine particle cement during the production of the fine particle cement. The amount used is ground injection drug solution 1 m ³ per 15kg or more.

Conventionally, such a fine particle cement has not been considered preferable when used in a small amount as a hardening agent for water glass, because the strength of the consolidated matter is low. However, as compared with fine particle calcium hydroxide, fine particle cement dissolves less even in the presence of water glass, so the initial viscosity of the chemical is small, and therefore the gel time can be lengthened and the permeability is excellent. It is effective when a chemical solution is used for preventing liquefaction.

Further, in the system (B) according to the present invention, in addition to the above-mentioned fine particle cement, a fine particle calcium hydroxide or a fine particle slag can be used in combination as a reactant. The object comes to exhibit high strength.

In this case, the particle size of the fine particle calcium hydroxide does not need to be specified as in the case of the fine particle calcium hydroxide used in the system (A), but it is preferable that the fine particles have an average particle size of 4 μm or less. It is calcium hydroxide.

The particle size of the fine particle slag is also the same as described above.
Although it is not particularly specified as long as it is a fine particle, the average particle diameter is preferably 4 microns. In the system (B) of the present invention, by using the fine particle slag together with the fine particle cement or the fine particle calcium hydroxide, as described above, a high-strength solidified product is obtained. In the present invention, since a fine particle powder is used, it is better to add a dispersant (fluidizing agent).

When the chemicals (A) and (B) according to the present invention obtained as described above are injected into the ground, any injection method can be adopted. As it grows like sand, it can be used together with cement or slag as far as the permeability allows, to further increase the strength of the consolidated matter.

As described above, the drug solution of the present invention has a molar ratio of 2.8.
It consists of the above-mentioned water glass and fine particle calcium hydroxide or fine particle cement of a specific particle size as the reactant, so that a small amount of the reactant is required, and most of the reactant is dissolved in the aqueous solution of water glass. And exhibit the same permeability as the solution type injection material.

Further, when the fine particle slag is used in combination with the above-mentioned chemical solution, the fine particle calcium hydroxide and the alkali of the fine particle cement effectively stimulate the latent hydraulic property of the fine particle slag to obtain a solidified substance having a large strength.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments.

Calcium hydroxide and cement used in the experiment were sample 1 (No. 1) and sample 2 (N
o. 2), three types of sample 3 (No. 3), two types of fine particle cement A (No. 4) and fine particle cement B (No. 5) were used. Table 1 shows the physical properties of each sample. The water glass used was JIS No. 3 product. Fine particle slag having the composition and the degree of pulverization shown in Table 1 was used.

[0032]

[Table 1]

Examples 1 to 12 and Comparative Examples 1 to 4 Water glass was used as solution A, and fine particles of calcium hydroxide shown in Table 1 were prepared.
Various ground injection chemicals were prepared using the fine particle cement as the liquid B. Gel time for the obtained ground injection chemical solution,
The consolidation strength and the state of penetration were measured, and the results are shown in Table 2.

The solidification strength of the chemical is filled in an acrylic mode of 5φ × 24 cm with Toyoura standard sand so as to have a relative density of 90%, and after saturation with water, the chemical is injected at an injection pressure of 1 kgf / cm ² and removed one day later. The mold was sealed and cured, and the strength was measured for 28 days.

The infiltration condition is as follows. Fill the acrylic mode of 5φ × 100 cm with Toyoura standard sand so that the relative density becomes 60%.
After water saturation, the drug solution was injected at an injection pressure of 2 kgf / cm ² , the case where the permeation distance was 40 cm or more was regarded as good, and the others were regarded as poor.

The gel time was determined by the inverted cup method, and the liquid was transferred to such an extent that the insoluble particles did not settle and adhere to the vessel wall. The liquid temperature was 20 ° C. In addition, in the test for observing the permeation state when the gel time is longer by 1 minute, the permeation distance becomes longer by 40 cm or more when the drug solution has a low viscosity, and it is a great effect that the gel time is extended by 1 minute with a short gel time.

[0037]

[Table 2]

In place of the finely divided calcium hydroxide of Example 3, a sample 3 having a particle size of 0.5 μm or less and 8% was used, and the gel time was 11 minutes.

Examples 13 and 14 and Comparative Examples 5 to 7 For some of the formulations of the above Examples and Comparative Examples,
The viscosity at the time of mixing the liquids A and B was measured. However, in addition to the above composition, 0.2 g of a fluidizing agent (MC helper: manufactured by Onoda Cement Co., Ltd.) was added to Liquid B. Mix liquids A and B with a mixer
After mixing and stirring for 0 seconds, the viscosity was immediately measured with a B-type viscometer. The liquid temperature was 20 ° C. Table 3 shows the results. The gel time of a solution-type drug solution is usually expressed as the time until the viscosity reaches 100 cps.

[0040]

[Table 3]

[0041]

As described above, according to the present invention, in the presence of a specific water glass, most of the fine particle calcium hydroxide or fine particle cement used as the reactant is dissolved, and the conventional inorganic glass is dissolved. As compared with the system solution type chemical solution, a permeable chemical solution having extremely excellent properties such as water stopping property, workability, and consolidation strength can be obtained. In particular, it has the features of being surely hardened even with a small amount of reactants, being surely gelled even if the gel time is lengthened, and having very little syneresis water from the homogel and little volume shrinkage. It is particularly effective as a liquid for preventing liquefaction that does not require strength.

Continuation of the front page (51) Int.Cl. ⁷ identification code FI // C09K 103: 00 (58) Field surveyed (Int.Cl. ⁷ , DB name) C09K 17/12 C09K 17/02 C09K 17/08 C09K 17/10 E02D 3/12 101

Claims (8)

(57) [Claims] 1. A chemical liquid for ground injection containing water glass and a reactant as main components, wherein the water glass has a molar ratio (SiO ₂ / Na ₂ O) of 2.8 or more, and Is a fine particle calcium hydroxide, and has the following requirements (1) to (3). (1) What average particle diameter der than 2 microns, 0.5 micro
Not more than 10% by weight . (2) 80% by weight or more containing 2.5 microns or less in particle size . (3) A particle size of 3.5 microns or more is 10% by weight or less . 2. The ground injection chemical solution according to claim 1, wherein the ground injection chemical solution further comprises fine particle cement as a reactant. 3. A chemical liquid for ground injection containing water glass and a reactant as main materials, wherein the water glass has a molar ratio (SiO ₂ / Na ₂ O) of 2.8 or more, and Has an average particle size of 2 microns or less and 0.5 microns or less
A chemical solution for injecting into the ground, which is a fine particle cement of 10% by weight or less . 4. The ground injection chemical according to claim 3, further comprising fine particle calcium hydroxide as a reactant. 5. The method according to claim 1, wherein the fine particles of calcium hydroxide as a reactant have an average particle size of 1.5 μm or less and a particle size of 0.5 μm or less is 10% by weight or less. The chemical for ground injection according to claim 1. 6. The chemical liquid for injection into the ground according to claim 2 or 4, wherein the mixing ratio of the fine particle calcium hydroxide and the fine particle cement is 90 to 5:10 to 95 by weight. For ground injection. 7. The ground injection chemical liquid according to claim 1, further comprising fine particle slag in the ground injection chemical liquid according to claim 1 or 3. 8. The chemical liquid for ground injection according to claim 1, wherein the amount of the fine particle calcium hydroxide used is 0.5 to 40 kg per 1 m ^{3 of the} chemical liquid for ground injection, and 2 to 2 kg per 1 m ^{3 of} water glass.
The chemical | medical solution for ground injection of Claim 1 which is 100 kg.