JP2987625B1 - Ground consolidated material - Google Patents

Abstract

Abstract: [Object] A ground consolidation material for injecting into a ground such as soft ground and consolidating the ground, which is mainly composed of dealkalized silica and cement or slaked lime obtained by removing alkali of water glass. As a result, a ground consolidation material that has a long gelation time, has excellent permeability, exhibits high consolidation strength, and has excellent durability of the consolidation body and is also excellent in environmental preservation is obtained. . The present invention comprises, as active ingredients, dealkalized silica obtained by removing part or all of sodium ions present in water glass from water glass, and cement, and if necessary, slaked lime, slag, colloidal silica. And the like. Further, from the water glass, contains dealkaline silica obtained by removing part or all of the sodium ions present in the water glass, and slaked lime as an active ingredient, and further contains slag as necessary. It can also be configured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground consolidation material that is injected into the ground such as soft ground and consolidates the ground.
It contains dealkalized silica and cement or slaked lime obtained by removing the alkali of water glass as a main component, has a long gelation time, has excellent permeability, exhibits high compaction strength, and further has a compacted body. The present invention relates to a ground consolidation material having excellent durability and environmental preservation.

[0002]

2. Description of the Related Art The following grout materials are conventionally known as a water glass-cement ground bonding material that is injected into the ground such as a soft ground to solidify the ground.

(A) Water glass-cement grout material. It is a suspended grout material called LW containing water glass and cement as main components.

(B) Acid silica sol-cement grout material. It is a grout material containing an acidic silica sol obtained by neutralizing the alkali of water glass with an excess acid, and cement.

(C) Colloidal silica-cement grout material. It is a grout material containing colloidal silica obtained by dealkalization from water glass and cement.

[0006]

The water glass-cement grout material (A) described above has a short gelation time of less than 2 minutes and is inferior in permeability, and the solidified material exhibits high alkalinity and dissolves or disintegrates. And inferior in durability.

[0007] Further, in the acidic silica sol-cement grout material of the above (B), the cement is immediately aggregated upon contact with the acidic silica sol, exhibits a thixotropic high viscosity and is inferior in permeability. Due to the consolidation, the gel does not show uniform gelation and the cement cannot sufficiently exhibit its strength.

In order to promote uniform gelation, it is conceivable to add and mix the above-mentioned (B) grout with a carbonate such as sodium carbonate or the like. It becomes high and instantaneously sets or gels in a few minutes.

Further, the colloidal silica of the above (C)
In the cement grout material, the colloidal silica is obtained by de-alkaliizing water glass, and then is heated and polymerized to give a colloid having a particle size of about 10 to 50 mm. When this comes into contact with the cement, it immediately produces a non-uniform gel due to the ionic reaction. Even if a gelling time regulator is added to this grout material, the gelling time is only about 20 to 30 minutes at the longest in a usual formulation.

[0010] Therefore, an object of the present invention is to contain a specific dealkalized silica and cement or slaked lime as active ingredients to provide a long gelling time, excellent permeability, high consolidation strength, and further consolidation. Excellent durability,
Another object of the present invention is to provide a ground consolidation material which is excellent in environmental preservation and has improved the disadvantages of the above-mentioned known technology.

[0011]

According to the present invention, there is provided, according to the present invention, a de-alkali silica obtained by removing part or all of sodium ions present in water glass from water glass. And cement as an active ingredient, and further contain slaked lime or slag as necessary.

Further, in order to achieve the above object, according to the present invention, dealkalized silica obtained by removing a part or all of sodium ions present in water glass from water glass, slaked lime, Containing as an active ingredient,
It is characterized by further containing slag as required.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

The dealkalized silica used in the present invention is obtained by removing a part or all of sodium ions present in water glass from water glass, and specifically, for example, an ion exchange resin or an ion exchange membrane. To obtain.

In the case of treatment with an ion-exchange resin, first, water glass is diluted with water to make a diluted water glass, and the diluted water glass is passed through a column filled with the ion-exchange resin, and alkali water in the water glass is removed. To obtain dealkalized silica.

In the case of treatment with an ion-exchange membrane, the above-mentioned water glass diluted with water is filled in an electrodialysis tank provided with a plurality of ion-exchange membranes between the negative and positive electrodes at intervals. Conduct electricity between both electrodes to perform electrodialysis of water glass,
The cations in the water glass are removed to obtain dealkalized silica.

The pH of the dealkalized silica obtained as described above is adjusted, for example, as follows. (1) Active silicic acid having a pH of 2 to 4 and low alkali silica having a pH of 7 to 12 are obtained by the above-described dealkalization treatment.
(2) Acids are added to the activated silicic acid to obtain stabilized activated silicic acid having a pH of 0.5 to 4. (3) An alkali is added to the activated silicic acid to obtain stabilized activated silicic acid having a pH of 7 or less or low alkali silica having a pH of 7 to 12. (4) Acids are added to the low alkali silica to obtain low alkali silica having a pH of 7 to 10.

The dealkalized silica used in the present invention is p
Active silicic acid having an H value of 7 or less or low alkali silica having a pH value of 7 to 12, particularly having a pH value of 0.5 to 12 and a silica concentration (stock solution concentration) of 1 to 10% by weight. It is industrially advantageous. In particular, as active silicic acid, pH 0.5 to
The low-alkali silica having a pH of 7 to 12 is suitable from the viewpoint of stability. In the present invention, p
Two or more kinds of dealkalized silicas having different H values or silica concentrations can be mixed to obtain a desired dealkalized silica.

Since the above-mentioned activated silicic acid gels in about one day if it is obtained through an ion exchange resin or an ion exchange membrane, it is preferable to add acids to stabilize the active silicic acid. Examples of the acids include inorganic acids such as hydrochloric acid and phosphoric acid or acid salts thereof, organic acids such as citric acid and tartaric acid and acid salts thereof, and inorganic neutral salts such as aluminum chloride which exhibit acidity in water. Can be

The acid obtained by adding an acid to an activated silicic acid having a pH of 2 to 4 and stabilizing it naturally has a pH value of 2 or less. However, the pH value of the stabilized activated silicic acid actually used is
It is preferably from 0.5 to 3. Although activated silicic acid exhibits acidity, the content of acid is extremely small, so that it does not inhibit the strength development of cement. For example, hydrochloric acid is added to 100 g of activated silica having a silica concentration of about 7% and a pH of 2.9.
When 0.2 g is added, the pH value of the activated silicic acid becomes 1.9. Even if a cement suspension is added to and mixed with the activated silicic acid as a consolidating material, it hardens sufficiently on the alkali side and exhibits high strength.

The above-mentioned low alkali silica having a pH of 7 to 12 is obtained directly by partial alkali dealation treatment of water glass, or obtained by further adjusting the pH thereof. High molar ratio and high silica concentration by adding colloidal silica or water glass, and the like.

Immediately after the alkali removal treatment, the above low alkali silica has the same molecular weight as the silica of the raw water glass and has a high activity, but is gradually polymerized and stabilized by the decrease in alkali. The stabilized low alkali silica is stable for 1 to 6 months, depending on the degree of dealkalization and the concentration of silica. For example, low alkali silica having a silica concentration of about 6% and a pH of 10.9 obtained by dealkalizing No. 3 water glass has a high molar ratio of about 15 and is stable for more than 2 months. .

The activated silicic acid having a pH of 7 or less obtained by adding specific alkalis to the activated silicic acid is also stabilized.

As the water glass which is a raw material of the dealkalized silica, JIS No. 3 water glass, water glass having a molar ratio of 3.5 to 4.5 which is industrially manufactured and marketed, and the like are suitable. In particular, water glass having a molar ratio of 3.5 to 4.5 is alkali-desorbed by a mixing method described below to obtain low alkali silica having a pH of 7 to 9 or an activity obtained by dealkalization by a column method described below. Water glass or colloidal silica is added to silicic acid to obtain low alkali silica having a pH of 6 to 9. All of these are suitable as dealkalized silica used in the present invention.

When the water glass is subjected to a dealkalization treatment, the water glass is preferably diluted with water. This is to prevent gelation of the ion exchange resin by active silicic acid, and to obtain stable active silicic acid.

As the alkali removal treatment using an ion exchange resin, a column method, a mixing method and the like are used. The column method is a method in which an ion-exchange resin is packed in a column, and the inside of the column is passed through a water glass diluted with water to remove alkali. The mixing method is a method in which an ion-exchange resin is mixed with water glass diluted with water, and after a lapse of several minutes, the ion-exchange resin is settled and removed from the mixed solution, or scooped and removed with a net.

The column method is suitable for producing activated silicic acid,
The mixing method is suitable for producing low alkali silica. The silica concentration of water glass diluted with water is 10 in the case of the column method.
% Or less, and in the case of the mixing method, when the viscosity increases, the yield of low alkali silica decreases.

As the dealkalization treatment using an ion exchange membrane, an electrodialysis method is used, which is particularly suitable for producing low alkali silica. In this case, the water glass diluted with water preferably has a SiO ₂ concentration of 2 to 15% and a current density of about 3 amps / dm ² .

Examples of the cement used in the present invention include Portland cement, alumina cement, blast furnace cement and the like, and particularly, fine particle cement having an average particle size of 10 μm or less or a Blaine specific surface area of 4000 cm ² / g or more. Is preferable for improving permeability.

The content of dealkalized silica in the ground compact of the present invention is not particularly limited, but is preferably 500 ml or less, more preferably 500 to 10 ml, per 1000 ml of the above-mentioned consolidated material blending liquid. Preferably, 250 to 10 ml is appropriate. Even if it is contained in an amount of 500 ml or more, no particular improvement in effect can be obtained. These contents are amounts calculated by assuming that the concentration of SiO ₂ derived from water glass is 6 %. If this content is expressed in grams,
0.5-30g per 1000ml
It is about.

Depending on the situation where the consolidated material of the present invention is used,
It is not necessary that the grout compounded liquid thickened by the cup inversion method does not completely flow out, and a compound whose viscosity is increased to about 500 cps with a B-type viscometer can also be used as a solidifying material. Such a consolidation material has a long permeation time, and has less clogging between sand particles than in the case of injecting a cement suspension. Excellent (small permeability).

The content of cement in the ground bonding material of the present invention is suitably 300 to 40 g per 1000 ml of the above-mentioned bonding material mixture. If the amount is more than 300 g, the permeability deteriorates, and if it is less than 40 g, the consolidation strength decreases.

The above-mentioned consolidated material of the present invention can further contain slaked lime or slag. As the slaked lime, finely soluble slaked lime having an average particle diameter of 3 μm or less is preferable. The content of slaked lime is 100
It is 2 to 40 g per 0 ml. Thereby, the consolidated material of the present invention keeps the permeability close to the solution type grout,
A high-strength compact can be obtained as a solution-type grout. In this case, the alkali-free silica is preferably low-alkali silica, and it is preferable to use sodium bicarbonate or sodium carbonate as a gelling time regulator.

As the slag, the specific surface area is 8000 cm ² / g
It is preferable to use the above-mentioned fine powder slag from the viewpoint of increasing the gelation time and improving the durability of the consolidated product.

The solidification material of the present invention can further adjust the gelation time and the initial gel strength by using colloidal silica or water glass, if necessary. This compounding time is optional.

Further, the consolidated material of the present invention may contain the above-described dealkalized silica and slaked lime as active ingredients, and may further contain slag if necessary. Slaked lime and slag are as described above, and their contents are also the same as described above.

The solidified material of the present invention obtained as described above may further contain a gel time adjusting agent to adjust the gel time of the blended liquid. Among these gelling time regulators, bicarbonates, carbonates, condensed phosphoric acids, etc. are used as those that increase the gelling time, and slaked lime, bicarbonate, Carbonate, calcium chloride, magnesium chloride, magnesium hydroxide and the like are used.

Such a gelling time regulator is usually added to the cement side or slaked lime side. However, when the alkali-removed silica is activated silicic acid, an alkali substance such as sodium bicarbonate or sodium carbonate is added to the activated silica side. It is more preferable to lengthen the gelation time or to obtain a uniform gel. However, when the added amount is large, the active silicic acid itself gels, so that all or a part of the gelling time regulator is added to the cement side.

The above-mentioned gelling time regulator is appropriately selected depending on the pH, silica concentration and the like of the dealkalized silica. The amount used is 0.1 to 40 per 1000 ml of the caking mixture.
The range of g is preferred.

In the present invention, the gelation time is shorter when using activated silicic acid as the alkali-free silica than when using low alkali silica. In order to obtain a consolidated material having a long gelation time, it is economically advantageous to use low alkali silica.

[0041]

The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

1. Materials used (1) dealkalized silica No. 1 to 7 shown in Table 1 were used.

[0043]

[Table 1]

In Table 1, Nos. 1 to 6 are 3 as raw water glass.
No. 7 is dealkalized silica obtained by using No. 5 water glass and dealkalizing each. The remarks in Table 1 show the materials used when adjusting the pH. Nos. 4 and 5 were prepared by treating a water diluent of No. 3 water glass with an ion exchange resin to prepare activated silicic acid having a pH of 2.8, adjusting the pH with No. 3 water glass, and adjusting the pH to the above. Value.

(2) Cement Portland cement and blast furnace cement having different compositions and pulverization degrees shown in Table 2 were used.

[0046]

[Table 2]

In Table 2, the average particle size of the cement of Sample No. 3 is about 3 microns.

(3) Slag A slag having the composition shown in Table 3 was used.

[0049]

[Table 3]

(4) Slaked lime Fine slaked lime having an average particle size of 2.8 microns was used.

(5) Gelling time adjusting agent As a typical gelling time adjusting agent, sodium hydrogen carbonate
(Reagent 1st class: NaHCO _ThreeIt was used.

(6) Colloidal Silica Water glass is treated with an ion exchange resin to remove most of the alkali, and granulated. Table 4 obtained from Asahi Denka Kogyo Co., Ltd.
The colloidal silica having the composition shown in Table 1 was used.

[0053]

[Table 4]

(7) Water glass (a) No. 3 water glass: specific gravity (20 ° C.) 1.39, SiO _{2
29.2%, Na 2 O9.5%,} JIS3 molar ratio 3.17
No. water glass was used.

(B) No. 5 water glass: specific gravity (20 ° C.) 1.3
2, SiO ₂ 25.5%, Na ₂ O 7.03%, molar ratio 3.
75 No. 5 water glass was used.

(8) Acidic silica sol An acidic silica sol of a water glass-sulfuric acid type having a pH of 1.8, a SiO ₂ concentration of 8.9%, and a gelation time of about 50 hours was used.

Examples 1 to 16 and Comparative Examples 1 to 4 The dealkalized silica was used as solution A, and the cements shown in Tables 2 and 3 were used.
Various samples of the present invention and comparative examples were prepared using slag and slaked lime as liquid B. The gel time, compaction strength, and permeation state of each of the obtained samples were measured, and the results are shown in Tables 5 and 6.

[0058]

[Table 5]

[0059]

[Table 6]

In Table 5, an acrylic mold with a consolidation strength of 5φ × 24 cm was filled with Toyoura standard sand so as to have a relative density of 60%. After saturation with water, grout material mixture (sample) at an injection pressure of 1 kgf / cm ^2. Was injected. Then, the mold was removed one day later, and the strength was measured for one day. On the other hand, the 28-day strength was measured for the one that had been hermetically sealed and cured according to the “Uniaxial Compression Test Method for Soil” of the Japan Society of Geotechnical Engineers.

[0061] osmotic conditions fills the Toyoura standard sand acrylic mold 5φ × 100cm so that a relative density of 60%, injected caking material blended solution with water saturated after injection pressure 2 kgf / cm ^2, penetration distance 20cm The above cases were evaluated as good, and the others were evaluated as poor. The gel time was 20 ° C. and the cup was inverted.

In Table 5, the sample No. in the column of the solution A is a sample No. of the dealkalized silica (described in Table 1). In addition, the samples having "-" in the permeation status column were not subjected to the permeation test because they were not formulations that emphasized permeation. Further, in Table 6, the Portland cement used was the sample No. 1 in Table 2.

Examples 17 to 24 and Comparative Example 5 A gel time adjusting agent was added to low alkali silica to obtain a blend having a long gel time. Table 7 shows the results. As the dealkalized silica, the sample No. 3 shown in Table 1 was used. The gel time was measured by the inverted cup method, and when there was no clear gelation time, it was indicated by the time when it became 500 cps with a B-type viscometer.

[0064]

[Table 7]

In Table 7, the strength of the homogel prepared by the formulation of each Example was 15 kgf / cm ² or more at 28 days strength. Comparative Example 5 used No. 3 water glass, and the others were No. 22 in Table 7.
, But did not thicken to 500 cps.

[0066]

As described above, ground consolidation obtained by treating water glass with an ion-exchange resin or an ion-exchange membrane, and then adding cement or further a slag or a gelling time adjusting agent to the base. The material can have the following effects.

1. Long gelling time and excellent permeability. Further, by adding the gelling time adjusting agent, not only a more uniform gelled product can be obtained, but also the gelling time can be lengthened. That is, in the present invention, the permeation possible time is long, and therefore, the permeation distance can be lengthened.

2. The consolidated material has high strength and excellent durability. That is, since the dealkalized silica used has less alkali than the conventionally used water glass, durability can be expected.

3. Excellent water conservation and environmental conservation. That is, since the alkali-free silica is used, the alkali is hardly eluted from the solidified material into the groundwater or the like.
In addition, since the dealkalized silica has sufficient stability, it can be manufactured in a factory, and the wastewater at the time of manufacturing can be sufficiently treated. Therefore, it can be said that this is also excellent in environmental preservation. Further, when the solidification material of the present invention is diluted with water, the reaction product of the cement and the dealkalized silica becomes floc-like precipitate, so that there is no outflow of the cement, which is also excellent in environmental preservation.

4. The same effect as described above can also be obtained with the consolidated material of the present invention relating to the combination of dealkalized silica and slaked lime, and if necessary, the combination with slag.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C09K 103: 00

Claims (4)

(57) [Claims] 1. A method according to claim 1, wherein the alkali glass is obtained by removing part or all of the sodium ions present in the water glass from the water glass, cement and / or slaked lime,
If necessary, further contain slag as an active ingredient,
Activated silicic acid whose pH is 7 or less,
Is a low alkali silica having a pH value of 7 to 12, and
Cement has an average particle size of 10 microns or less, or brane
Fine cement with a specific surface area of 4000 cm ² / g or more
A ground consolidation material characterized by the following. 2. The soil consolidation material according to claim 1, further comprising colloidal silica. 3. The method according to claim 1, wherein the content of the dealkalized silica and the cement is 1000
The ground consolidation material according to claim 1, which is 500 to 10 ml and 300 to 40 g, respectively. 4. The method according to claim 1, wherein the content of SiO _{2 in} the dealkalized silica is from 0.5 to 3 per 1000 ml of the solidified mixture.
The ground consolidation material according to claim 1, which weighs 0 g.