JP2012172060A - Grout and method for solidifying ground - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grout and a method for solidifying the ground, further improved in the aspect of working easiness and ground-improving effect in addition to the aspect of cost and environmental burden reduction.SOLUTION: The grout includes: amino acid(s) generating ammonia as a result of being subjected to metabolic degradation by microorganisms in the ground; a calcium salt; and phosphoric acid and/or phosphate. By using the grout or the method for solidifying the ground using the same, the speed of solidifying the ground can be adjusted; therefore, for example, solidification of the grout during its injection into the ground can be prevented, and, in addition, uniformly solidifying the ground and adjusting the period of time necessary for solidifying the ground can be easily conducted.

Description

  The present invention relates to a method for consolidating grout and ground, and more particularly to a grout comprising amino acids, calcium salts and phosphoric acid and / or phosphate, and a method for consolidating ground using these.

  In fields such as civil engineering, grout using an injection material called grout for the purpose of improving defective areas such as cracks and voids in the ground, improving the strength of soft ground, improving the permeability of water-permeable ground, or waterproofing spring water. The injection method is widely adopted. Particularly in recent years, development of a ground improvement technique using a new grouting using a microorganism called biogrout has been promoted in order to control water permeability and improve the strength of the ground using a mechanism of generation of a cement substance by microorganisms.

  In general, biogrout is (1) the crystallization reaction proceeds relatively slowly compared to the grout only by chemical reaction, so it is easy to adjust the time required for ground improvement. (2) Environmental impact It has the merit that it can be expected to be small and (3) technology development with reduced cost.

  As a method for improving the ground using biogrouts reported so far, for example, a solution containing calcium ions, glucose and pH buffer is added to the ground, and glucose is metabolized to the added yeast or microorganisms in the ground at the same time. Method of improving ground by decomposing to generate carbon dioxide, causing the generated carbon dioxide to react with calcium ions to precipitate calcium carbonate, and production of urea and urease Bacteria are added to the ground, urease producing bacteria metabolize urea to generate ammonia, adjust pH, metabolize urea to generate carbon dioxide, and react the generated carbon dioxide with calcium ions To improve the ground by depositing calcium carbonate (Patent Document 2, Non-Patent Document 2, Permit 2) Metabolism of an activated silica solution, which is alkaline, glucose and a culture of microorganisms present in the soil of the yeast or the target ground, and a culture of microorganisms present in the soil of the yeast or the target ground Examples include a method of improving the ground by generating carbon dioxide by means of, and promoting gelation by the generated carbon dioxide (Patent Document 3, Non-Patent Document 3).

JP 2006-169940 A Special table 2008-524096 JP 2009-155855 A

Kawasaki et al., Applied Geology, Vol. 47, No. 1, pp. 2-12, 2006 Harkes M.H. P. Et al., Ecol. Eng. 36, 112-117, 2010 Terashima et al., JSCE Proceedings C, Vol. 65, No. 1, pp. 120-130, 2009

  However, the physicochemical characteristics of the ground to be improved vary widely, and in order to cope with them, the development of more diverse grout and ground improvement techniques is desired. Further, from the viewpoint of cost and environmental load reduction, further improvement is desired for conventional grout and ground improvement techniques.

  Therefore, an object of the present invention is to provide a method for solidifying the grout and the ground which are further improved in terms of ease of construction and ground improvement effect in addition to cost and environmental load reduction.

  The present inventors can control the form and volume of precipitates mainly composed of calcium phosphate by changing the type and mixing ratio of calcium salts and phosphates in grout, and amino acids, calcium salts and phosphoric acids. The present inventors have found that a grout containing a salt prevents reprecipitation of precipitates and promotes crystallization of calcium phosphate by a moderate ground pH raising action of amino acids, and has completed the following inventions.

(1) A grout comprising an amino acid, calcium salt, and phosphoric acid and / or phosphate that are metabolized and decomposed by microorganisms in the ground to generate ammonia.

(2) The grout according to (1), wherein the calcium salt and phosphoric acid and / or phosphate are calcium phosphate.

(3) The grout according to (1), wherein the calcium salt and phosphoric acid and / or phosphate are calcium salt excluding calcium phosphate and phosphoric acid and / or phosphate excluding calcium phosphate.

(4) A method for consolidating the ground, which comprises the following steps (i), (ii) and (iii): (i) an amino acid which is metabolized and decomposed by microorganisms in the ground to generate ammonia; Adding calcium salt and phosphoric acid and / or phosphate to the ground; (ii) metabolizing the amino acid into microorganisms in the ground to generate ammonia; (iii) pH of the ground by the ammonia. In accordance with the amount of the calcium salt and phosphoric acid and / or phosphate to precipitate calcium phosphate in the ground.

(5) A method for consolidating the ground, which comprises the following steps (iv), (v), (vi) and (vii); (iv) a step of preparing an aqueous calcium phosphate solution; A step of adding an aqueous solution of calcium phosphate and an amino acid that is metabolized by microorganisms in the ground to generate ammonia; (vi) a step of metabolizing the amino acid to microorganisms in the ground to generate ammonia; (vii) A step of raising the pH of the ground with ammonia to precipitate calcium phosphate in the ground.

  According to the method for consolidating the grout and the ground according to the present invention, the speed at which the ground consolidates can be adjusted. For example, the grout can be prevented from solidifying during the injection, and the ground can be made uniform. It is possible to easily adjust the time required for solidification or ground consolidation. In addition, calcium phosphate produced in the ground by the method of solidifying the grout or ground according to the present invention is a main component of bone and is a safe and harmless substance, and therefore solidifies the grout or ground according to the present invention. According to the method, it is possible to improve and consolidate the ground safely and harmlessly, without burdening the environment. In addition, the calcium phosphate produced in the ground increases in strength over time as shown in the previous report (FIG. 1; Tung MS et al., Kluwer Academic Publishers, page 1-19, 1998). Since it changes to hydroxyapatite, according to the method of consolidating the grout or ground according to the present invention, the ground strength can be improved over a long period of time. Furthermore, the method for consolidating the grout and ground according to the present invention is easy to obtain and inexpensive because it uses fertilizer components such as ammonium phosphate and calcium nitrate. Recyclable as an agricultural sample.

It is a figure which shows the change of the crystal form of a calcium phosphate with progress of time and the change of a phosphate concentration. In the figure, the vertical axis indicates the phosphate concentration, and the horizontal axis indicates time. It is a figure which shows the relationship between the solubility of calcium phosphate, and the pH of a solution. In the figure, the vertical axis represents calcium ion concentration, and the horizontal axis represents pH. Monoammonium phosphate {NH ₄ H ₂ PO ₄ (hereinafter referred to as “MAP”)}, diammonium phosphate {(NH ₄ ) ₂ HPO ₄ (hereinafter referred to as “DAP”)} and calcium nitrate {Ca ( NO _{3) 2} (hereinafter, referred to as "CN".) for aqueous solution obtained by changing the mixing ratio of}, is a graph showing the results of measurement of pH. In the figure, the vertical axis represents pH, and the horizontal axis represents the mixing ratio of MAP and DAP corresponding to the sample name (number part). It is a figure which shows correlation with pH, a precipitate volume ratio, and the form of a precipitate about the aqueous solution which changed the mixing ratio of MAP, DAP, and CN. In the figure, the vertical axis represents the precipitate volume ratio, and the horizontal axis represents the pH. The form of the precipitate is indicated by the shape of the plot (◯, □ or Δ), and the mixing ratio of MAP and DAP is indicated by the color (black, gray, or white). Regarding the aqueous solution in which the mixing ratio of MAP, DAP and calcium acetate {Ca (CH ₃ COO) ₂ (hereinafter referred to as “CA”)} is changed, the correlation between the pH, the volume ratio of the precipitates, and the form of the precipitates is obtained. FIG. In the figure, the vertical axis represents the precipitate volume ratio, and the horizontal axis represents the pH. The form of the precipitate is indicated by the shape of the plot (◯, □ or Δ). Among the aqueous solutions in which the mixing ratio of MAP, DAP and CN is changed, CN-C-c0, CN-C-c1, CN-C-c2, CN-C-c3, CN-C-c4, CN-C- It is a figure which shows the volume of a precipitate about c5, CN-C-c6, CN-C-c7, CN-C-c8, CN-C-c9, and CN-C-c10. In the figure, the mixing ratio of MAP, DAP and CN and the measurement result of pH in each sample are shown at the bottom of each sample name. It is a figure which shows the result of having observed the volume and form of the precipitate about the aqueous solution which changed final concentration. In the figure, the final concentration of each sample is shown at the bottom of each sample name. It is a figure which shows the result of having measured the pH of the soil which added asparagine aqueous solution of various density | concentrations, glutamine aqueous solution, glycine aqueous solution, urea aqueous solution, and deionized water. In the figure, the vertical axis indicates pH, and the horizontal axis indicates the number of days that have elapsed after the addition of each aqueous solution and deionized water. As a result of measuring pH and observing the form of precipitates for a negative control grout containing no amino acid (control sample) and a sample obtained by adding soil to a grout according to the present invention (test sample) FIG.

  Hereinafter, the method for consolidating the grout and the ground according to the present invention will be described in detail. The grout according to the present invention comprises an amino acid, calcium salt, and phosphoric acid and / or phosphate that are metabolized by microorganisms in the ground to generate ammonia.

  `` Grout '' generally refers to soil improvement, cement paste, mortar, chemicals, etc. that are injected and filled into gaps, joints, cracks, etc. of structures, and in the present invention, for the purpose of consolidation and improvement of the ground This is an injection material for the ground to be used. The form of the “grouting” in the present invention is not particularly limited as long as it is such an injection material. For example, it is in a liquid state, a gel state, a solid state, or a mixture of liquid and gel. And a mixture of a liquid and a solid, a mixture of a gel and a solid, and a mixture of a liquid, a gel and a solid. The term “biogrout” refers to a grout using microbial metabolism.

  The grout can be used in a mode according to the target ground, but the usage mode is not particularly limited. For example, the grout may be used as it is by a method such as spraying, pouring, splitting, kneading, or the like. In this case, for example, it may be dissolved, semi-dissolved or suspended in a solvent and used in the same manner, or a pulverized or crystallized material may be sprayed or kneaded. In addition, the grout can be used repeatedly as well as once for the same ground, and when used repeatedly, its form can be changed.

  “Ground” generally refers to the land that serves as the basis for laying the surface of the earth (the earth's surface), the earth's crust, a workpiece, etc. (Kojien 6th edition, Iwanami Shoten), but in the present invention, it is not limited to the earth's surface or the earth's crust. It refers to the range from the ground surface to the deep underground. The main constituents include, for example, clay (having a particle size of less than 3.9 μm in geology) and silt (having a particle size of 3.9 to 62.5 μm in geology), clay And debris such as sand (with a particle size of 62.5 μm or more and less than 2 mm in geology), gravel (with a particle size of 2 mm or more in geology), Examples thereof include soft or hard viscous soil, sandy soil, gravelly soil, gravel, soil, stone, rock, bedrock, or a mixture thereof. In the present invention, “ground” is used interchangeably with “soil”, “soil”, “debris”, “gravel”, “stone”, “rock”, or “rock”.

  The “microorganism” in the present invention is not particularly limited as long as it has the property of metabolizing amino acids to generate ammonia, and examples of such microorganisms include bacteria, algae, protists, fungi and the like. One or more microorganisms can be used which can be selected from such microorganisms. Moreover, the aspect is also not limited, For example, the thing of aspects, such as a microbial mass, can be mentioned. In addition, the “microorganism in the ground” in the present invention exists in the ground to be subjected to the administration of the grout according to the present invention and the method for solidifying the ground according to the present invention before the administration and construction. In addition to those, those added to the ground at the time of administration, construction, or later, and those combined with these can be mentioned. When adding to the ground at the time of administration or construction, or after that, for example, lactic acid bacteria, yeast, natto bacteria, and other microorganisms that have been used in foods and are commercially available, or the ground that is subject to administration or construction Those collected from ground other than the ground can be used. Furthermore, the microorganism can be repeatedly added after the administration or construction.

  Examples of the “amino acid metabolized by microorganisms to generate ammonia” in the present invention include, for example, cysteine, histidine, isoleucine, methionine, serine, valine, alanine, glycine, leucine, proline, threonine, phenylalanine, arginine, tyrosine, tryptophan. , Aspartic acid, asparagine, glutamic acid, glutamine, lysine, cystine, hydroxyproline, hydroxylysine, thyroxine, α-phosphoserine, desmosine, β-alanine, sarcosine, ornithine, creatine, γ aminobutyric acid, opine, theanine, tricolominic acid, kainin Acid, domoic acid, ibotenic acid, achromeric acid, and the like. In the present invention, one or more selected from such amino acids can be used. Amino acid can be used.

  Examples of the “calcium salt” in the present invention include calcium carbonate, calcium phosphate, calcium acetate, calcium hydroxide, calcium lactate, calcium nitrate, and calcium chloride. In the present invention, the calcium salt is selected from such calcium salts. One or more calcium salts that can be used can be used. For example, “calcium carbonate” includes calcium bicarbonate in addition to calcium carbonate, and “calcium phosphate” includes calcium hydrogen phosphate and tricalcium phosphate in addition to calcium phosphate. This is also the case for the compound.

  As the “phosphate” in the present invention, for example, ammonium phosphate, sodium phosphate, sodium pyrophosphate, acidic sodium pyrophosphate, sodium tripolyphosphate, sodium tetrapolyphosphate, sodium hexametaphosphate, acidic sodium hexamentalate, Examples thereof include potassium phosphate, potassium metaphosphate, zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, lithium phosphate, lithium hexafluorophosphate, and the like in the present invention. One or more phosphates can be used that can be selected.

  The “grout comprising an amino acid, calcium salt, and phosphoric acid and / or phosphate that are metabolized and decomposed by microorganisms in the ground to generate ammonia” according to the present invention is not limited as long as the characteristics of the present invention are not impaired. Such substances include, for example, other microorganisms, sugars, minerals, substances that promote metabolism of microorganisms such as organic nitrogen sources other than amino acids, pH adjusting (buffer) agents, curing materials, Swelling agent, fluidizing agent, alumina cement, fine aggregate, setting modifier, thickener, antifoaming agent, hydrogen polysiloxane silicone oil, clay minerals such as slag, diatomaceous earth, white clay, bentonite, and quartzite powder, volcanic ash Natural silicate minerals such as, incinerated ash, and blast furnace slag.

  The grout according to the present invention is intended to solidify or improve the ground by precipitating or existing calcium phosphate in the ground. Calcium phosphate precipitated or present in the ground may be precipitated or existed from calcium salt and phosphate. For example, an amino acid and an aqueous calcium phosphate solution in which grout according to the present invention is metabolized and decomposed by microorganisms to generate ammonia. When it is included, the pH in the ground may be raised by ammonia generated in the ground to cause calcium phosphate to precipitate or exist.

  That is, the “calcium salt and phosphate and / or phosphate” in the present invention may be “calcium phosphate” or “calcium salt excluding calcium phosphate and phosphate excluding phosphate and / or calcium phosphate”.

Next, the present invention provides a method for consolidating the ground. The method for consolidating the ground according to the present invention comprises (i) a step of adding an amino acid, a calcium salt, and phosphoric acid and / or phosphate that are metabolized and decomposed by microorganisms in the ground to generate ammonia;
(Ii) a step of metabolizing the amino acid into microorganisms in the ground to generate ammonia,
(Iii) increasing the pH of the ground with the ammonia according to the amount of the calcium salt and phosphoric acid and / or phosphate to precipitate calcium phosphate in the ground;
The above steps (i), (ii), and (iii) are included. In the method for consolidating the ground according to the present invention, the description of the same or equivalent structure as that of the grout according to the present invention described above will not be repeated.

  In step (i), “amino acids, calcium salts and phosphoric acid and phosphate that are metabolized and decomposed by microorganisms in the ground to generate ammonia” may be added to the ground in advance, and each may be added separately to the ground. May be added. Moreover, when they are solid, pulverized or crystallized materials may be added to the ground, and those dissolved, semi-dissolved or suspended in a solvent may be added to the ground.

  In the present invention, calcium phosphate is produced by a reaction between calcium ions derived from a calcium salt and ions such as phosphate ions, pyrophosphate ions, hydrogen phosphate ions derived from phosphoric acid or phosphate. In addition to ions derived from calcium salts and ions derived from phosphoric acid and phosphate, components in the ground such as fluoride ions and chloride ions may react to form.

  Here, although calcium phosphate in the present invention is as described above, more specifically, calcium dihydrogen phosphate monohydrate, calcium dihydrogen phosphate anhydrous, dicalcium phosphate anhydrous, diphosphate phosphate Calcium dihydrate, octacalcium phosphate, β-tricalcium phosphate, α-tricalcium phosphate, tetracalcium phosphate, whitlockite, hydroxyapatite, fluoroapatite, chloroapatite, carbonic acid-containing apatite and the like can be mentioned.

  The pH range to be raised by generating ammonia in the ground can be appropriately set according to the amount of calcium salt, phosphoric acid, and phosphate added to the ground, as shown in Example 2 described later. it can. Further, as to the pH range to be raised, as shown in the previous report (FIG. 2; Tung MS et al., Kluwer Academic Publishers, page 1-19, 1998), the solubility of calcium phosphate can be any type. Since the pH at which the solubility is minimized differs depending on the type of calcium phosphate, in addition to changing depending on the pH, the pH range to be raised can be appropriately set according to the type of calcium phosphate to be precipitated according to these reports. it can. Furthermore, it can set suitably in the range with which pH 5.8-8.6 which is the water quality reference value of the water pollution prevention method is satisfy | filled.

  Regarding the amount of phosphoric acid and phosphate added to the ground, as shown in the previous report (Tung MS et al., Kluwer Academic Publishers, page 1-19, 1998), as the phosphate concentration decreased, calcium phosphate In some cases, the amount of phosphoric acid and phosphate added to the ground can be appropriately set according to these reports.

The calcium salt and phosphoric acid and / or phosphate pH (G _pH ) added in step (i) is preferably 1 <G _pH <11, more preferably 1 <G _pH ≦ 10, and 1 <G _pH ≦ 9. Is more preferable, and 1 <G _pH ≦ 8 is even more preferable. That may be a 5.8 ≦ _{G pH} ≦ 8.6 in the range satisfying pH5.8~8.6 a water quality standard value of the Water Pollution Control Law.

Next, the second aspect of the method for consolidating the ground according to the present invention is as follows.
(Iv) preparing a calcium phosphate aqueous solution;
(V) adding to the ground an amino acid that is metabolized and generated by the calcium phosphate aqueous solution and microorganisms in the ground to generate ammonia;
(Vi) Metabolizing the amino acid into microorganisms in the ground to generate ammonia,
(Vii) increasing the pH of the ground with the ammonia and precipitating calcium phosphate in the ground;
The above steps (iv), (v), (vi), and (vii) are included.

  The “calcium phosphate aqueous solution” in step (iv) may be prepared by dissolving calcium phosphate in a solvent, or by dissolving phosphate except for calcium phosphate or phosphate and calcium salt except for calcium phosphate in a solvent. May be. Here, in the present invention, the calcium phosphate aqueous solution includes not only a solution in which calcium phosphate is completely dissolved, but also a calcium phosphate suspension and a colloidal solution.

  About the usage aspect of the "amino acid" of process (v), it is the same as that of process (i) mentioned above.

  The method for consolidating the ground according to the present invention may include other steps as long as the characteristics thereof are not impaired. Examples of the other steps include, for example, each of the grouts according to the present invention described above. In addition to the step of adding a substance, a step of boring the ground, a step of stirring the ground, a step of washing the ground, and a step of detecting calcium phosphate precipitated or present in the ground can be exemplified.

  By the method of solidifying the ground according to the present invention, calcium phosphate can be precipitated mainly in the gaps of the ground, the ground can be consolidated, and ground improvement effects such as a decrease in water permeability and an improvement in ground strength are obtained. It is done.

  Hereinafter, the method of consolidating the grout and the ground according to the present invention will be described based on examples. Note that the technical scope of the present invention is not limited to the features shown by these examples.

<Example 1> Examination of pH in aqueous solution in which mixing ratio of MAP, DAP and CN is changed (1) Preparation of aqueous solution Monoammonium phosphate {NH ₄ H ₂ PO ₄ ; Wako Pure Chemical Industries, Ltd. (hereinafter “MAP”) }}, Diammonium phosphate {(NH ₄ ) ₂ HPO ₄ ; Wako Pure Chemical Industries (hereinafter referred to as “DAP”)} and calcium nitrate {Ca (NO ₃ ) ₂ ; "CN"))} was dissolved in deionized water at 2 mol / L to prepare MAP aqueous solution, DAP aqueous solution and CN aqueous solution.

  Subsequently, the hydrogen ion concentration (hereinafter referred to as pH) of each aqueous solution was measured using a Lacom tester pH meter (waterproof type pHSpear; ASONE). The results are shown below.

MAP aqueous solution: pH 4.0 to 4.5
DAP aqueous solution: pH 7.8-8.3
CN aqueous solution: pH 4.0-6.0

  Next, MAP aqueous solution and DAP aqueous solution were mixed at various ratios to prepare a 2 mol / L ammonium phosphate aqueous solution. Subsequently, by mixing ammonium phosphate aqueous solution and CN aqueous solution at various ratios, a total of 77 samples of aqueous solutions having different mixing ratios of MAP, DAP and CN were prepared, and a0-a10, b0-b10, c0 c10, d0 to d10, e0 to e10, f0 to f10, and g0 to g10. The following table shows the mixing ratio of MAP, DAP and CN in each sample, the final concentration of each sample, and the final concentration of phosphate source (phosphate ion; hereinafter referred to as P) and calcium source (calcium ion: hereinafter referred to as Ca). It is shown in 1.

(2) pH measurement of aqueous solution About each sample of this Example (1), after leaving still at 20 degreeC for 3 months, pH was measured using the Lacom tester pH meter (waterproof type | mold pHSpear; ASONE Co., Ltd.). The measurement results are shown in FIG.

  When comparing the pH of the samples belonging to FIGS. 3A, 3B, and 3C, as shown in FIGS. 3A, 3B, and 3C, in a0 to a10, a0 <a1 <a2 <a3 <a4 <a5 <a6 <a7 <a8 < a9 <a10, as shown in FIG. 3A, b0 <b1 <b2 <b3 <b4 <b5 <b6 <b7 <b8 <b9 <b10 for b0 to b10, and c0 <c1 <c2 <c3 <c4 for c0 to c10. <C5 <c6 <c7 <c8 <c9 <c10, as shown in FIG. 3B, d0 <d1 <d2 <d3 <d4 <d5 <d6 <d7 <d8 <d9 <d10, and e0 to e10 at d0 to d10. e0 <e1 <e2 <e3 <e4 <e5 <e6 <e7 <e8 <e9 <e10, as shown in FIG. 3C, for f0 to f10, f0 <f1 <f2 <f3 <f4 <f5 <f6 <f7 <f8 <F9 <f10 and g0 In g10 g0 <g1 <g2 <g3 <g4 <g5 <g6 <was g7 <g8 <g9 <g10. From these results, it was found that the pH of the aqueous solution was higher as the mixing ratio of DAP was higher than that of MAP.

  3A, when the pH values of samples having the same numerical part of the sample name are compared, as shown in FIG. 3A, b0> c0> a0, b1> c1> a1, b2> c2> a2, b3> c3> a3, b4> c4> a4, b5> c5> a5, b6> c6> a6, b7> c7> a7, b8> c8> a8, b9> c9> a9 and b10> c10> a10. From these results, it was revealed that the pH of the aqueous solution was higher as the final concentration of the calcium source was smaller than the final concentration of the phosphate source.

  Moreover, when comparing the pH of samples having the same numerical part of the sample name in FIG. 3B, as shown in FIG. 3B, d0> e0> a0, d1> e1> a1, d2> e2> a2, d3> e3> a3, d4> e4> a4, d5> e5> a5, d6> e6> a6, d7> e7> a7, d8> e8> a8, d9 = a9> c9 and d10 <e10 <a10. From these results, when the mixing ratio of DAP is smaller than MAP: DAP = 1: 9, the pH is lower as the final concentration of the aqueous solution is larger, and the mixing ratio of DAP is larger than MAP: DAP = 1: 9. It was revealed that the higher the final concentration of the aqueous solution, the higher the pH.

  Further, in FIG. 3C, when the pH values of the samples having the same numerical part of the sample names are compared, as shown in FIG. 3C, f0≈g0≈a0, f1≈g1≈a1, f2≈g2≈a2, f3≈g3≈ a3, f4≈g4≈a4, f5≈g5≈a5, f6≈g6≈a6, f7≈g7≈a7, f8≈g8 <a8, f9≈g9 <a9, f10≈g10 <a10. From these results, when the mixing ratio of DAP is smaller than MAP: DAP = 3: 7, the concentration of the phosphate source is changed from 0.1 mol / L to 1 mol / L with respect to the final concentration of 1 mol / L of the calcium source. The pH hardly changes even when the pH is changed between MAP and DAP. When the mixing ratio of DAP is larger than MAP: DAP = 3: 7, the concentration of the phosphate source is 1 mol with respect to the final concentration of 1 mol / L of the calcium source. In the case of / L, it became clear that the pH was higher than that of the phosphoric acid source concentration of 0.1 mol / L and 0.5 mol / L.

  From the above results, it was revealed that the pH of the aqueous solution can be changed by changing the mixing ratio of MAP, DAP and CN. In particular, it has been found that the pH of the aqueous solution can be changed without changing the final concentrations of the phosphate source and the calcium source by changing the mixing ratio of MAP and DAP in the aqueous ammonium phosphate solution. That is, it was shown that even in a grout in which an amino acid was added to the aqueous solution, the pH of the grout could be changed without changing the final concentrations of the phosphate source and the calcium source.

<Example 2> Examination of relationship between pH of aqueous solution and volume and form of precipitate (1) Preparation of aqueous solution The mixing ratio of MAP, DAP and CN was changed by the method described in Example 1 (1). A total of 176 samples of the aqueous solution were prepared, and CN-A-a0 to CN-A-a10, CN-A-b0 to CN-A-b10, CN-A-c0 to CN-A-c10, CN-A-d0 ~ CN-A-d10, CN-B-a0-CN-B-a10, CN-B-b0-CN-B-b10, CN-B-c0-CN-B-c10, CN-B-d0-CN -B-d10, CN-C-a0 to CN-C-a10, CN-C-b0 to CN-C-b10, CN-C-c0 to CN-C-c10, CN-C-d0 to CN-C -D10, CN-D-a0 to CN-D-a10, CN-D-b0 to CN-D-b1 0, CN-D-c0 to CN-D-c10 and CN-D-d0 to CN-D-d10. The mixing ratio of MAP, DAP and CN, and the final concentrations of phosphate source and calcium source in each sample are shown in Table 2 below.

Further, instead of CN as calcium acetate {Ca (CH ₃ COO) ₂ ; Wako Pure Chemical Industries, Ltd. (hereinafter referred to as “CA”)}, a total of 132 samples of aqueous liquids in which the mixing ratio of MAP, DAP and CA was changed were used. CA-A-a0 to CA-A-a10, CA-A-b0 to CA-A-b10, CA-A-c0 to CA-A-c10, CA-B-a0 to CA-B- a10, CA-B-b0 to CA-B-b10, CA-B-c0 to CA-B-c10, CA-C-a0 to CA-C-a10, CA-C-b0 to CA-C-b10, CA-C-c0 to CA-C-c10, CA-D-a0 to CA-D-a10, CA-D-b0 to CA-D-b10, and CA-D-c0 to CA-D-c10 were used. The mixing ratio of MAP, DAP and CA, and the final concentrations of phosphate source and calcium source in each sample are shown in Table 3 below.

(2) Measurement of pH of aqueous solution, measurement of volume of precipitate, and observation of morphology According to the method described in Example 1 (2), each sample of Example (1) was allowed to stand at 20 ° C. for 3 months. After that, the pH was measured using a Lacomtester pH meter (waterproof type pHSpear; ASONE). Further, the volume of the precipitate is visually measured, and the ratio of the volume of the precipitate to the volume of the aqueous solution is calculated. This is the volume ratio of the precipitate (when the volume of the aqueous solution and calcium phosphate is equal to 1.0) It was. Moreover, the form of the precipitate was observed and evaluated in the following three stages. In addition, the color attached | subjected to the symbol shows the sample name, ie, the mixing ratio of MAP and DAP, as follows.

Form of precipitate ○: Crystalline (transparent or white solid)
□: Gel (precipitate does not deform even if the container is tilted)
Δ: Liquid (deforms when the container is tilted and has fluidity)
Sample name (numerical part) and MAP: DAP (ratio)
Black: 0, 10: 0
Ash: 10, 0:10
White: 1 to 9, 9: 1 to 1: 9

  In addition, the main component of the precipitate in the aqueous solution containing calcium salt and phosphate includes calcium ions derived from calcium salt, phosphate ions derived from phosphate, pyrophosphate ions, hydrogen phosphate ions, and the like. Calcium phosphate produced by reaction with ions. In general, crystallization of calcium phosphate proceeds from a gel to a crystal. In addition, when calcium phosphate becomes liquid, with the passage of time, crystallization does not proceed any more and the liquid state is maintained. The volume of calcium phosphate is gel-like> crystalline.

  Subsequently, the pH of each sample, the precipitate volume ratio, and the form of the precipitate were plotted on a graph with the pH on the horizontal axis and the precipitate volume ratio on the vertical axis. These graphs were prepared for each sample in which the final concentration of the phosphate source and the final concentration of the calcium source were the same. FIG. 4 shows the results for a total of 176 samples of the aqueous solution in which the mixing ratio of MAP, DAP, and CN was changed, and FIG. 5 shows the results for 132 samples in which the mixing ratio of MAP, DAP, and CA was changed. Moreover, the photograph which shows the volume of a precipitate about CN-C-c0-CN-C-c10 is shown in FIG.

  As shown in FIG. 4 and FIG. 6, the precipitate volume ratios are Aa, Ab, Ac, Ad, Ba, BB, Bc, Bd, C−. In any graph of a, Cb, Cc, Cd, Da, Db, Dc, and Dd, the higher the pH, the larger the precipitate volume ratio, It was revealed that the pH and the precipitation volume ratio are almost positively correlated.

  In addition, the form of the precipitate is Aa, Ba, BB, Ca, Cb, Cc, Da, and Db. When the pH was high, the precipitate was a gel. In Ba, the precipitate was in the liquid state when the pH was near neutral. On the other hand, in A-b, A-c, A-d, B-c, B-d, C-d, D-c and D-d, the precipitate was crystalline regardless of the change in pH. It was.

  Further, as shown in FIG. 5, in the graphs of Ab and Ac, the precipitate volume ratio is low when the pH is high, while the precipitate volume ratio is small, while Aa, Ba, Bb, In any of the graphs Bc, Ca, Cb, Cc, Cd, Da, Db, Dc, and Dd, the precipitate volume ratio is increased when the pH is high. Is large, that is, the pH and the precipitate volume ratio are almost positively correlated.

  In addition, the form of the precipitate is Ba, Bc, Ca, Cb, Cc, Cd, Da, Db, Dc, and Dd. When the pH was low, the precipitate was crystalline, and when the pH was high, the precipitate was gel. On the other hand, in Aa and Bb, the precipitate is crystalline regardless of the change in pH, and in Ab and Ac, the precipitate is in a liquid state regardless of the change in pH. It was.

  From these results, it became clear that as the pH of the aqueous solution increased, the volume of precipitates mainly composed of calcium phosphate increased. That is, it was shown that the volume of the precipitate mainly composed of calcium phosphate can be controlled by controlling the pH in the grout obtained by adding an amino acid to the aqueous solution.

  In addition, in an aqueous solution with a predetermined mixing ratio, the rate of crystallization of calcium phosphate slows down as the pH of the aqueous solution increases, whereas in an aqueous solution with a different mixing ratio, the pH of the aqueous solution increases. It was revealed that the rate of crystallization of calcium phosphate did not change much. That is, it was shown that the rate of crystallization of calcium phosphate can be controlled by controlling the mixing ratio of MAP, DAP and CN or CA in the grout obtained by adding an amino acid to the aqueous solution. Furthermore, it has been clarified that the rate of crystallization of calcium phosphate can be controlled by controlling pH in an aqueous solution having a predetermined mixing ratio.

<Example 3> Examination of relationship between concentration of aqueous solution and volume and form of precipitate (1) Preparation of aqueous solution According to the method described in Example 1 (1), the mixing ratio of MAP, DAP and CN was 0:10. : 10 and final concentrations of 0.1 mol / L, 0.5 mol / L, 1.0 mol / L and 1.5 mol / L were prepared as a, b, c and d.

(2) Observation of volume and form of precipitate After a, b, c and d of Example (1) were allowed to stand at 20 ° C. for 3 months, the volume and form of the precipitate were visually observed. The result is shown in FIG.

  As shown in FIG. 7, the volume of the precipitate was b <a <c <d. Moreover, as for the form of the deposit, a, b, and c were gelatinous, and d was crystalline.

  From these results, it became clear that when the final concentration of the aqueous solution was changed, the volume of precipitates mainly composed of calcium phosphate and the rate of crystallization of calcium phosphate changed. That is, it was shown that the volume of precipitates mainly composed of calcium phosphate and the rate of crystallization of calcium phosphate can be controlled by controlling the final concentration of grout obtained by adding an amino acid to the aqueous solution.

<Example 4> Examination of ground pH increasing action by amino acid (1) Preparation of amino acid aqueous solution and urea aqueous solution Asparagine, glutamine, glycine and urea are dissolved in deionized water so as to have the following concentrations, respectively, asparagine aqueous solution and glutamine An aqueous solution, an aqueous glycine solution, and an aqueous urea solution were prepared.

Asparagine aqueous solution; 0.1 mol / L, 0.01 mol / L, about 0.15 mol / L (saturated aqueous solution)
Glutamine aqueous solution: 0.1 mol / L, 0.01 mol / L, about 0.25 mol / L (saturated aqueous solution)
Glycine aqueous solution; 0.1 mol / L, 0.01 mol / L, 1.0 mol / L
Urea aqueous solution; 0.1 mol / L, 0.01 mol / L, 1.0 mol / L

(2) Addition of amino acids and urea to the ground Soil was collected from Hokkaido University Farm and Okayama University Farm, and divided into 25g pieces, totaling 13 samples of Hokkaido University Farm soil and 13 samples of Okayama University Farm soil. Prepared. Okayama has 13 soil samples from Hokkaido University Farm as North 1, North 2, North 3, North 4, North 5, North 6, North 7, North 8, North 9, North 10, North 11, North 12, and North 13. Thirteen samples of university farms were Oka 1, Oka 2, Oka 3, Oka 4, Oka 5, Oka 6, Oka 7, Oka 8, Oka 9, Oka 11, Oka 11, Oka 12, and Oka 13.

  Subsequently, 32.5 mL each of the asparagine aqueous solution, glutamine aqueous solution, glycine aqueous solution, urea aqueous solution and deionized water of Example (1) was added to each sample as described below.

North 1, Oka 1: Deionized water (control)
North 2, Oka 2: Asparagine aqueous solution 0.01 mol / L
North 3, Oka 3: Asparagine aqueous solution 0.1 mol / L
North 4, Oka 4: Asparagine aqueous solution about 0.15 mol / L (saturated aqueous solution)
North 5, Oka 5: Glutamine aqueous solution 0.01 mol / L
North 6, Oka 6: Glutamine aqueous solution 0.1 mol / L
North 7, Oka 7: Glutamine aqueous solution 0.25 mol / L (saturated aqueous solution)
North 8, Oka 8: Glycine aqueous solution 0.01 mol / L
North 9, Oka 9: Glycine aqueous solution 0.1 mol / L
North 10, Oka 10: Glycine aqueous solution 1 mol / L
North 11, Oka 11: Urea aqueous solution 0.01 mol / L
North 12, Oka 12: urea aqueous solution 0.1 mol / L
North 13, Oka 13: Urea aqueous solution 1 mol / L

(3) Measurement of pH Each sample of Example (2) was allowed to stand for 6 weeks, and during that time, the 0th day (immediately after sample preparation), the 1st day, the 2nd day, the 3rd day, the 7th day, 14 On the 21st, 21st, 28th, 35th and 42nd days, the pH of the soil was measured using a Lacom Tester pH meter (waterproof pHSpear; ASONE).

  About the measurement result of pH, it represented to the graph for every kind of added aqueous solution. A graph for North 1, North 2, North 3 and North 4 is shown in FIG. 8A, and a graph for Oka 1, Oka 2, Oka 3 and Oka 4 is shown in FIG. 8B, North 1, North 5, North 6 8C, the graph for Oka 1, Oka 5, Oka 6 and Oka 7 in D in FIG. 8, the graph for North 1, North 8, North 9 and North 10 in FIG. 8 E, graphs for Oka 1, Oka 8, Oka 9 and Oka 10 are shown in FIG. 8 F, graphs for North 1, North 11, North 12 and North 13 are shown in FIG. The graphs for 11, Oka 12 and Oka 13 are shown in FIG.

  As shown in FIG. 8A, the pH in North 2, North 3 and North 4 is on Day 1, Day 2, Day 3, Day 7, Day 14, Day 21, Day 28, Day 35 And at both time points on day 42, it was higher than the pH in North 1.

  In addition, the pH in North 2, North 3 and North 4 all increased slightly during the 3rd day after the addition, and was almost constant or moderate between the 7th and 42nd days. Rose to. The line graph showing the pH change with the elapsed days had the same shape between North 2, North 3 and North 4.

  Further, as shown in FIG. 8B, the pH in Oka 2, Oka 3 and Oka 4 is 1st, 2nd, 3rd, 7th, 14th, 21st, 28th, 35th. It was higher than the pH in Oka 1 at both time points of Day 2 and Day 42.

  In addition, the pH in Oka 2, Oka 3 and Oka 4 increased somewhat remarkably during the third day after addition, and gradually increased or decreased during the seventh to 42 days. The line graph showing the pH change with the elapsed days had the same shape among Oka 2, Oka 3 and Oka 4.

  Further, as shown in FIG. 8C, the pH in North 5, North 6 and North 7 is 1st, 2nd, 3rd, 7th, 14th, 21st, 28th, 35th, It was higher than the pH in North 1 at both the day and day 42 time points.

  In addition, the pH in North 5, North 6, and North 7 increased slightly remarkably during the third day after the addition, and gradually increased during the seventh to 42 days. The line graph showing the pH change with the elapsed days had a similar shape between north 5, north 6 and north 7.

  Further, as shown in FIG. 8D, the pH in Oka 5, Oka 6 and Oka 7 is 1st, 2nd, 3rd, 7th, 14th, 21st, 28th, 35th. It was higher than the pH in Oka 1 at both time points of Day 2 and Day 42.

  In addition, the pH in Oka 5, Oka 6 and Oka 7 increased somewhat remarkably during the third day after the addition, and gradually increased during the seventh to 42 days. The line graph showing the pH change with the elapsed days had the same shape among Oka 5, Oka 6 and Oka 7.

  Also, as shown in FIG. 8E, the pH in North 8 is at North 1 at the time of Day 1, Day 2, Day 3, Day 7, Day 14, Day 21, and Day 28. It was higher than pH, about the same as the pH in North 1 at day 35 and lower than the pH in North 1 at day 42. On the other hand, the pH in the north 9 and the north 10 is any point on the 1st day, 2nd day, 3rd day, 7th day, 14th day, 21st day, 28th day, 35th day and 42nd day. Also higher than the pH in North 1.

  In addition, the pH in North 8 slightly increased during the 3rd day after the addition, gradually increased during the 7th to 28th days, and between the 35th and 42nd days. Slightly decreased. On the other hand, the pH in the north 9 and the north 10 both increased slightly remarkably during the third day after the addition, and was almost constant or gradually increased from the seventh day to the 42nd day. . The line graph showing the pH change with the elapsed days had the same shape between the north 9 and the north 10.

  Further, as shown in FIG. 8F, the pH in Oka 8 is that in Oka 1 at the time of Day 1, Day 2, Day 3, Day 7, Day 14, Day 21, and Day 28. It was higher than the pH, almost the same as the pH in Oka 1 at the 35th day, and lower than the pH in Oka 1 at the 42nd day. On the other hand, the pH in Oka 9 and Oka 10 is any point on day 1, day 2, day 3, day 7, day 14, day 21, day 28, day 35, day 42 Also, the pH in Oka 1 was higher.

  In addition, the pH in Oka 8 slightly increased during the third day after the addition, and was almost constant or gradually increased during the seventh to 28th days. From the 42nd day onward, it decreased slightly. On the other hand, the pH in Oka 9 and Oka 10 both increased slightly remarkably during the third day after the addition, and gradually increased from the seventh day to the 42nd day. The line graph showing the pH change with the elapsed days had the same shape between Oka 9 and Oka 10.

  Also, as shown in FIG. 8G, the pH in north 11 is higher than the pH in north 1 at the time of day 1, day 2, day 3, day 7, day 14 and day 21, At day 28, it was about the same as the pH in North 1, and was lower than the pH in North 1 at Days 35 and 42. On the other hand, the pH in the north 12 and the north 13 is any point on the 1st day, 2nd day, 3rd day, 7th day, 14th day, 21st day, 28th day, 35th day and 42nd day. Also higher than the pH in North 1.

  In addition, the pH in the north 11 increased during the 14th day after the addition and decreased during the 21st to 42nd days. On the other hand, the pH in the north 12 continued to rise until the 42nd day after the addition. On the other hand, the pH in the north 13 increased rapidly and remarkably during the 14th day after the addition, and was almost constant between the 21st and 42nd days. That is, the line graph showing the pH change with the elapsed days has a completely different shape between the north 11, the north 12, and the north 13.

  Further, as shown in FIG. 8H, the pH in Oka 11 is the pH in Oka 1 at the time of Day 1, Day 2, Day 3, Day 7, Day 14, Day 21, and Day 28. It was lower than the pH in Oka 1 at the time of 35th day and 42nd day. On the other hand, the pH in Oka 12 and Oka 13 is any time point on Day 1, Day 2, Day 3, Day 7, Day 14, Day 21, Day 28, Day 35, Day 42, and Day 42 Also, the pH was higher than that in Kita 1 and Oka 1, respectively.

  Moreover, pH in Oka 11 rose during the 14th day after the addition, and dropped during the 21st day to the 42nd day. On the other hand, the pH in Oka 12 continued to rise from the addition until the 42nd day. On the other hand, the pH in Oka 13 rose sharply and significantly during the 21st day after the addition, and was substantially constant during the 28th to 42nd days. That is, the line graph showing the pH change with the elapsed days has a completely different shape between Oka 11, Oka 12, and Oka 13.

  From the above results, it has been clarified that when asparagine, glutamine, a certain concentration or more of glycine and a certain concentration or more of urea are added to the soil, the pH of the soil increases. That is, it was revealed that the pH of the ground can be increased by adding amino acids to the ground.

  In addition, asparagine, glutamine, and glycine at a certain concentration or higher gradually increase the pH of the soil regardless of the concentration, whereas urea clearly changes the effect of increasing the pH of the soil depending on the concentration. became.

<Example 5> Examination of crystal maintenance action by amino acid (1) Sample preparation According to the method described in Example 1 (1), MAP: DAP: CN = 1: 1: 2 and the final concentration was 2 mol / L. An aqueous solution was prepared, and two solutions containing 4 mL of the prepared aqueous solution in a tube were prepared. Subsequently, 2 mL of 0.1 mol / L glutamine aqueous solution was added to one side to prepare a grout according to the present invention, and then 24 g of soil collected from a Hokkaido University farm was added to make a test sample, and the other was 2 mL of deionized water. After preparing a negative control grout containing no amino acids, 24 g of soil collected from Hokkaido University Farm was added to prepare a control sample, which was allowed to stand for 4 weeks.

(2) pH measurement and observation of precipitate morphology
For the test sample and the control sample of this Example (1), immediately after sample preparation and after 4 weeks, the pH of the soil was measured using a Lacom tester pH meter (waterproof pHSpear; ASONE), and the precipitate Was observed visually. The result is shown in FIG.

  As shown in FIG. 9, immediately after sample preparation, the control sample and the test sample both had a pH of 5.0, and crystalline precipitates were confirmed. On the other hand, after 4 weeks, the control sample had a pH of 4.7 and the precipitate dissolved and became liquid, whereas the test sample had a pH of 5.1 and the precipitate was the sample. It was confirmed that it was crystalline as it was immediately after preparation.

  From these results, the grout comprising amino acid, calcium salt and phosphate prevents lowering of the pH of the ground and prevents redeposition of precipitates mainly composed of calcium phosphate, and increases the pH of the ground. Thus, it was revealed that crystallization of calcium phosphate can be promoted.

<Example 6> Water permeability test (1) Preparation of grout After suspending soil of Hokkaido University farm in sterilized water, microbial extract water was prepared by filtering. Subsequently, glutamine was dissolved in the microorganism-extracted water to a concentration of 0.1 mol / L to prepare a microorganism-extracted glutamine aqueous solution.

  Next, in the method described in Example 1 (1), deionized water is replaced with a microorganism-extracted glutamic acid aqueous solution, and a grout having a final concentration of 2 mol / L with MAP: DAP: CN = 1: 1: 2 is obtained. This was used as a test grout. Also, in the method described in Example 1 (1), deionized water is replaced with microbial extract water to prepare an aqueous solution with MAP: DAP: CN = 1: 1: 2 and a final concentration of 2 mol / L. (In other words, the microorganism-extracted glutamic acid aqueous solution was replaced with deionized water in the test grout), and this was used as a control solution.

(2) Sample preparation Two sample cylinders having a diameter of 5 cm and a height of 5.1 cm packed with about 150 g of sand were prepared as test samples and control samples.

  The test grout and control solution of this example (1) were each added to a flat bottom container (inner diameter about 10 cm, height about 2 cm). The test sample was placed in a flat bottom container containing a test grout, and the control sample was placed in a flat bottom container containing a control solution, and allowed to stand at room temperature for 24 hours. By this operation, the test grout and the control solution were sucked and injected into the soil in the sample cylinder from the lower end of the sample cylinder using the capillary action.

(3) Measurement of soil permeability About the test sample and the control sample of this example (2), using the soil permeability meter DIK-400 (Daikai Chemical Co., Ltd.), the water level was changed according to the attached specifications. The indoor water permeability test by the method was conducted to measure the water permeability coefficient.

  As a result, the hydraulic conductivity of the test sample was smaller than that of the control sample.

  From these results, it became clear that the water permeability of the ground can be remarkably reduced by the grout containing amino acid, calcium salt and phosphate.

<Example 7> Uniaxial compressive strength test (1) Preparation of grout Test grout and control liquid were prepared by the method described in Example 6 (1).

(2) Sample preparation Two molds each having a diameter of 5 cm and a height of 10 cm filled with approximately 320 g of sand were prepared as test samples and control samples.

  After adding 73.3 mL each of the test grout of this example (1) to the test sample and 73.3 mL of the control solution of this example (1) to the control sample, the test sample was stored in a humid environment at 20 ° C. for 28 days. . Subsequently, the mold was removed from the sample, and the uniaxial compression strength was measured using a uniaxial compression tester according to the attached specifications.

  As a result, the uniaxial compressive strength was larger in the test sample than in the control sample.

  From these results, it was confirmed that the ground strength can be remarkably improved by the grout comprising amino acid, calcium salt and phosphate.

Claims (5)

  A grout comprising an amino acid, calcium salt, and phosphoric acid and / or phosphate that are metabolized by microorganisms in the ground to generate ammonia.   The grout of claim 1, wherein the calcium salt and phosphoric acid and / or phosphate are calcium phosphate.   The grout according to claim 1, wherein the calcium salt and phosphoric acid and / or phosphate are calcium salt excluding calcium phosphate and phosphoric acid and / or phosphate excluding calcium phosphate. A method for consolidating the ground, which comprises the following steps (i), (ii) and (iii):
(I) a step of adding an amino acid, calcium salt, and phosphoric acid and / or phosphate that are metabolized and decomposed by microorganisms in the ground to generate ammonia;
(Ii) a step of metabolizing the amino acid into microorganisms in the ground to generate ammonia,
(Iii) A step of causing the pH of the ground to rise with the ammonia according to the amount of the calcium salt and phosphoric acid and / or phosphate to precipitate calcium phosphate in the ground. A method for consolidating the ground, which comprises the following steps (iv), (v), (vi) and (vii):
(Iv) preparing a calcium phosphate aqueous solution;
(V) adding to the ground an amino acid that is metabolized and generated by the calcium phosphate aqueous solution and microorganisms in the ground to generate ammonia;
(Vi) Metabolizing the amino acid into microorganisms in the ground to generate ammonia,
(Vii) A step of increasing the pH of the ground with the ammonia to precipitate calcium phosphate in the ground.

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