TWI427139B - Site Penetration Base Material and Site Injection Method - Google Patents

Description

Site material and site injection method for site injection

The present invention relates to a substrate for injecting a substrate material and a site for injecting cerium oxide particles containing colloidal cerium oxide, and more particularly to a site improvement method for use in a weak site or to prevent liquefaction of a site, reinforcement of a foundation site, and the like. The site is filled with the base material and the site injection method.

Injecting a material into a site where the site is consolidated, such as a weak ground plate, etc., an injection material of a bismuth citrate as a main material, an acidic active citric acid aqueous solution composed of a soda citrate and an acid as a main material, Or an injection material having a neutral colloidal cerium oxide as a main material (Patent Documents 1 and 2).

However, these injection materials all contain a large number of bases or salts. When the content of the alkali or the salt is large, the alkali or the salt is freely detached from the consolidated body for a long period of time, and the shrinkage of the consolidated body is broken, and durability such as a decrease in strength of the consolidated body is deteriorated. In order to improve such shortcomings, in recent years, proposals have been made to treat succinic soda by cation exchange resin or ion exchange membrane, to remove the acidic active citric acid aqueous solution of the alkali in citrate soda, or to further use colloidal dioxide. The floor injecting material of the crucible (see, for example, Patent Documents 3 to 5).

The site injecting material described in Patent Document 3 is composed of acidic colloidal cerium oxide and cinnamic acid soda, and is excellent in the point of obtaining a high-strength injection material, but the slight difference in material blending causes a large change in gelation time. And there are difficulties in practical use.

The site injecting material described in Patent Document 4 is added to active tannic acid. An acid agent such as an inorganic acid or tartaric acid improves the stability of the active tannic acid, but it is only a matter of extending the gelation time for several days, and it is difficult to say that the operation at the construction site is easy. Further, there has been described a method in which an alkalizing agent is added to make the gelation time longer and the storage stability is improved. However, the slight difference in the blending of the materials in this method causes a large variation in the gelation time and is practically difficult. .

The site injecting material described in Patent Document 5 is an active material composed of active tannic acid, soda citrate, and an acidic reactant (organic acid such as inorganic acid or citric acid or gluconic acid, and phosphoric acid in the examples). In the aqueous solution of citric acid, since the concentration of cerium oxide is several parts by weight, the transportation cost from the place of manufacture (worksite) to the construction site becomes expensive, and the problem is that it is gelled in a few days and cannot be stored in a large amount in the engineering. Not resolved yet.

As described above, the use of the site injecting material using the active tannic acid is limited to only a part, and the two components of the colloidal ceria and the soda citrate are used as the main materials, and the site injecting material for blending the gelling agent is widely used. The gelation time of the two components is mainly adjusted by the blending ratio of the soda citrate to the gelling agent, and phosphoric acid, sulfuric acid or sodium hydrogensulfate is used as the gelling agent. Among them, the phosphoric acid has a three-stage pKa value (the logarithm of the reciprocal of the acid dissociation constant, pKa1 = 1.83, pKa2 = 6.43, pKa3 = 11.46) is an acid which easily adjusts the gelation time. However, there are doubts about the eutrophication caused by the accumulation of phosphorus in lakes or rivers. On the other hand, the pKa2 of sulfuric acid and sodium hydrogen sulfate is 1.74 and smaller is difficult to adjust the gelation time acid.

However, the above colloidal cerium oxide is generally commercially available as a cerium oxide sol, and is usually a cerium oxide stabilized by heating or the like of an active phthalic acid obtained by ion soda resin by soda citrate. For products with a concentration of 20 to 50% by weight, the average particle diameter is about 10-20 nm. The site injecting material using the colloidal cerium oxide as a main material is a material having high permeability, and is excellent in durability and the like.

[Advanced technical literature]

[Patent Literature]

[Patent Document 1] JP-A-54-73407

[Patent Document 2] Japanese Patent Laid-Open No. Hei 3-66794

[Patent Document 3] Japanese Patent Publication No. 4-136088

[Patent Document 4] Japanese Patent Publication No. 11-181425

[Patent Document 5] JP-A-2000-109835

Therefore, the present invention provides a substrate for injecting a substrate for which the gelation time can be easily adjusted, the permeability to the ground is excellent, and the durability or the consolidation strength is high, even if the phosphoric acid is not used at all or the composition is reduced in usage. And the use of its site injection method as a target.

As a result of intensive research to solve such problems, the present inventors have found that a colloidal cerium oxide and a ceric acid soda are used as main materials, and a specific acid is used as a gelling agent for the substrate for injecting the substrate, and the gelation time is obtained. The adjustment is easy, the permeability to the ground is excellent, and the durability and the consolidation strength are high.

That is, the present invention is a substrate material for in-situ implantation, which is composed of colloidal cerium oxide and cinnamic acid soda as a main material, and contains a mineral acid and an organic acid as a gelling agent, and has a pH of 2 to 7 at 25 ° C.

More preferably, the pH buffer solution of the organic acid containing the inorganic acid and the reciprocal of the acid dissociation constant at 25 ° C is 1.0 to 7.0, and the buffer is used for the implantation of the pH between 2 and 7. Base material.

The above inorganic acid is preferably a mixed acid of sulfuric acid, phosphoric acid or sulfuric acid and phosphoric acid.

The above organic acid is preferably selected from the group consisting of oxalic acid, maleic acid, tartaric acid, malic acid, citric acid, and lactic acid.

The best combination is that the inorganic acid is sulfuric acid and the organic acid is oxalic acid or citric acid.

Furthermore, the present invention also provides a method of injecting the above-mentioned site for injecting the substrate material into the ground.

According to the present invention, it is possible to provide a substrate for injecting a substrate which is easy to adjust the gelation time, has excellent permeability to the ground, and has high durability and high consolidation strength. By injecting the ground material for injecting the ground of the present invention into the ground plate, the stability of the ground plate can be remarkably improved.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

The colloidal cerium oxide of the main material of the base material for flooring injection of the present invention is not particularly limited, and a commercially available product can be used. Further, the bismuth citrate of the second main material is not particularly limited, and a commercially available product can be used.

The substrate material for in-situ injection of the present invention contains a mineral acid and an organic acid as a gelling agent. As the inorganic acid, sulfuric acid, phosphoric acid or a mixed acid of sulfuric acid and phosphoric acid is preferred, and such acidic salts can also be used. A strong acid such as hydrochloric acid or nitric acid which is completely dissociable is difficult to adjust the gelation time. Further, when a mixed acid of sulfuric acid and phosphoric acid is used as the inorganic acid, the concentration of phosphoric acid in the substrate for injecting the substrate is preferably 0.4 mol/L or less.

The organic acid is preferably an organic acid having a logarithmic value (pKa) of an acid dissociation constant at 25 ° C of 1.0 to 7.0, and such an organic acid may be an amine group such as aspartic acid, alanine or glycine. Acids; carboxylic acids such as formic acid, citric acid, acetic acid, oxalic acid, tartaric acid, lactic acid, phthalic acid, propionic acid, maleic acid, butyric acid, malic acid, and the like. Among them, oxalic acid (pKa1=1.04, pKa2=3.82), maleic acid (pKa1=1.84, pKa2=5.83), tartaric acid (pKa1=2.87, pKa2=3.97), malic acid (pKa=3.23, pKa=4.77), Citric acid (pKa1 = 2.90, pKa2 = 4.35, pKa3 = 5.69) and lactic acid (pKa1 = 3.64) are more preferred. Since the molecular weight of oxalic acid is small, the amount of acid equivalent by weight is large and optimum. The necessary condition for the substrate for injecting the ground plate of the present invention is that the colloidal ceria and the soda citrate are mainly composed of the above-mentioned inorganic acid and organic acid as a gelling agent, and the pH at 25 ° C is 2~. 7.

More preferably, the substrate material for in-situ implantation of the present invention comprises a pH buffer solution of an organic acid having a logarithmic value (pKa) of 1.0 to 7.0 in combination with a mineral acid at a reciprocal of an acid dissociation constant at 25 ° C, and at a pH of 2 to 7. It is better to have a buffer between them. As a result of the present inventors, the gelation time has a large dependence on the pH of the injection material, and the pH of the material can be adjusted by applying a liquid composition of the substrate material into the pH buffer solution. The variation is small, and even if the concentration of the injection material is small due to the groundwater, the fluctuation of the pH is small, so that the variation of the gelation time becomes small, and the predetermined gelation time can be easily substantially realized.

The colloidal cerium oxide of the main material of the base material for flooring injection of the present invention is not particularly limited, and a commercially available product can be used. In addition, the second main material of citric acid soda is not particularly limited, and a commercially available product can be used, and it is preferable to use No. 3 citrate soda or No. 4 citrate soda, and No. 3 citrate soda is mass-produced, so it is cheap and good. .

The colloidal ceria used in the present invention is produced by using soda citrate as a raw material. The soda citrate is pre-diluted to a concentration of cerium oxide of 3 to 7% by weight, and is contacted with a strong acid cation exchange resin to remove sodium to form an active aqueous citric acid solution. The active citric acid aqueous solution has a pH of about 2 to 4, and an alkali agent is added to the active citric acid aqueous solution to form a pH of 9 to 10.5, and the heating is carried out at 60 to 100 ° C to grow the particles (mature), or to add an alkali agent heated to 60 to 100 ° C. The active citric acid aqueous solution is brought to a pH of 9 to 10.5, and the temperature is maintained at 60 to 100 ° C to cause the particles to grow (mature). After the particle size was 5 to 20 nm, the concentration of cerium oxide was 10% by weight or more by concentration under reverse osmosis. The particle diameter of the present invention is preferably 5 to 20 nm.

The colloidal cerium oxide preferably contains at least 10% by weight of cerium oxide particles. Further, the concentration of cerium oxide is preferably in the range of 10 to 30% by weight. In order to simplify transportation and reduce transportation costs, products with a high concentration of cerium oxide are preferred.

The substrate material for the site for injecting of the present invention can be further combined with other additives, for example, a blending gelation time adjuster. For example, in order to shorten the gelation time, slaked lime, calcium chloride, magnesium chloride, magnesium hydroxide or the like can be used. Or use cement (portal cement, alumina cement, blast furnace cement) and slag to adjust the gelation time or initial gel strength.

In the substrate for injecting the ground plate of the present invention, the liquid A in which the colloidal cerium oxide, the inorganic acid, the organic acid and the water are mixed and dissolved is prepared, and the liquid B of the sodium citrate is diluted with water, and the liquid A and the B are injected during the injection. Mix the liquids.

In the method of injecting the site, there is a counter-stabilizing site (improved site), and the substrate for injecting the substrate of the present invention is pressurized and injected through a chemical injection pipe to consolidate and strengthen the site or stop the water to stabilize the site. Methods. Further, the site improvement method is to inject two or more kinds of the base material for the site for injecting the present invention, for example, a substrate for injecting the substrate having a different particle diameter or a different reactant, and injecting it into a multi-phase to consolidate and strengthen the site or stop the water. A method of stabilizing the site.

Further, the gelation time of the substrate material for injecting the substrate of the present invention may be adjusted arbitrarily, and it is preferably in the range of several seconds to several tens of hours depending on the purpose. The gelation time is not particularly limited depending on the presence or absence of groundwater, the type of soil, the soil sand accumulation structure, and the state around the injection site. Further, a one-shot mode, a 1.5-shot mode, a two-shot mode, or the like can be used.

[Examples]

Hereinafter, the present invention will be described in detail by way of examples, but the invention is not limited thereto.

(using materials)

Colloidal cerium oxide: Silicadol 30, manufactured by Nippon Chemical Industry Co., Ltd., cerium oxide concentration = 30% by weight

Sodium citrate: special soda citrate, manufactured by Nippon Chemical Industry Co., Ltd., cerium oxide concentration = 26% by weight, Na ₂ O = 7% by weight, specific gravity 1.32

Phosphoric acid: 75% phosphoric acid, manufactured by Nippon Chemical Industry Co., Ltd.

Sulfuric acid: 75% sulfuric acid, manufactured by Nippon Chemical Industry Co., Ltd.

Oxalic acid dihydrate, citric acid monohydrate, maleic acid, DL-malic acid, lactic acid, tartaric acid: reagent

<Example 1>

The material formulation of the liquid B is shown in Table 1, and the liquid oxalic acid concentration of the liquid A is 0.1 mol/L, and the material formulation of the sulfuric acid is changed. The material formulation of the liquid A is shown in Table 2. The mixing of the two liquids was carried out by rapidly adding the liquid B to the liquid A under stirring. The pH and gelation time of the mixed solution (injected material) were measured, and the results are shown in Table 3, FIG. 1 and FIG. A glass electrode type pH meter was used for the pH measurement.

<Example 2>

The same material as in Example 1 was used for the liquid B, and the concentration of the oxalic acid in the liquid A was changed to 0.05 mol/L, and the blending amount of the sulfuric acid was changed. The material formulation of the liquid A was shown in Table 4. The gelation time of the pH of the mixed solution (injected material) was measured, and the results are shown in Table 5, FIG. 1 and FIG.

<Comparative Example 1>

The same material as in Example 1 was used for Liquid B, and No liquid was used for Liquid A. For the acid, the material formulation of the liquid A was described in Table 6 only in the material formulation in which the blending amount of sulfuric acid was changed. The gelation time of the pH of the mixed solution (injected material) was measured, and the results are shown in Table 7, FIG. 1 and FIG.

As is apparent from Fig. 1, in the case of only sulfuric acid (without adding oxalic acid), the pH of the sulfuric acid blending amount is sharply changed in the region of pH 3 to 4, and it is extremely difficult to control the pH, and it is estimated that the control of the gelation time is also difficult. As the concentration of oxalic acid increases, the slope of the curve becomes gentler. The concentration of oxalic acid is 0.05 mol/L or more and the value is almost linear in the range of pH 3~4. The control of pH is relatively easy. It is speculated that the control of gelation time also changes. Easy.

<Example 3>

An example of an injection material using various organic acids, phosphoric acid, and sulfuric acid. The liquid B is the same material as in the first embodiment, and the blending amount of the organic acid and the phosphoric acid of the liquid A is constant, and the material formulation for changing the blending amount of sulfuric acid is used. The material formulation is described in Tables 8-1 to 3. The gelation time of the pH of the mixed solution (injected material) was measured, and the results are shown in Tables 9-1 to 3, FIGS. 3 and 4.

<Comparative Example 2>

An example in which an organic acid is not used and only an injection material of phosphoric acid and sulfuric acid is used. In the case of the B liquid, the same material as in the first embodiment was used, and the blending amount of the liquid A phosphoric acid was constant, and the material formulation in which the blending amount of sulfuric acid was changed was described. The material formulation of the liquid A was described in Tables 10-1 to 2. The gelation time of the pH of the mixed solution (injection material) was measured, and the results are shown in Tables 11-1 to 2, and FIG. 3 and FIG. In the region of pH 3 to 4 in the figure, the pH of the sample added with the organic acid changes linearly with respect to the sulfuric acid concentration (the amount of sulfuric acid added). In addition, the magnitude of the change is strongly suppressed compared to the case where no organic acid is used.

<Example 4>

An example of an injection material using an organic acid and phosphoric acid. The formulation of the B solution is shown in Table 12. The liquid A was based on the formulation described in Table 13, and the amount of the organic acid was adjusted by changing the amount of addition, and finally, water was added to 300 ml. The gelation time of the pH of the mixed solution (injected material) was measured, and the material formulations of the liquid A were described in Tables 14-1 to 7. It is also formulated to further add phosphoric acid to the liquid A in addition to the organic acid. The pH and gelation time of the AB mixed solution (injected material) were measured, and the results are shown in FIGS. 5 and 6. In the region of pH 3 to 4 in the figure, the sample added with the organic acid changes linearly as compared with the change in the pH of the added phosphoric acid. Among them, oxalic acid (pKa1=1.04, pKa2=3.82) has a steep slope due to a small pKa.

Fig. 1 is a graph showing the relationship between the concentration of sulfuric acid and the pH in the base material for the ground floor injection.

Fig. 2 is a graph showing the relationship between the sulfuric acid concentration and the gelation time in the base material for the ground floor injection.

Fig. 3 is a graph showing the relationship between the concentration of sulfuric acid and the pH in the base material for the ground floor injection.

Fig. 4 is a graph showing the relationship between the sulfuric acid concentration and the gelation time in the base material for the ground floor injection.

Fig. 5 is a graph showing the relationship between the acid concentration (removing the phosphate component of the substrate) and the pH in the substrate material for the ground floor injection.

Fig. 6 is a graph showing the relationship between the acid concentration (removing the phosphate component of the matrix) and the gelation time in the disk injecting substrate material.

Claims (3)

A base material for injecting a ground plate, characterized by: colloidal cerium oxide and cinnamic acid soda as main materials, containing sulfuric acid and phosphoric acid and selected from the group consisting of oxalic acid, maleic acid, tartaric acid, malic acid, citric acid and lactic acid The organic acid of the group acts as a gelling agent and has a pH of 2 to 7 at 25 ° C, and has a buffering effect between the pH. The substrate material for site injecting according to the first aspect of the invention, wherein the organic acid is oxalic acid or citric acid. A site injecting method for injecting a ground material for injecting a site as described in claim 1 or 2 into a ground plate.