Sandy soil solidification method based on bionic induction of calcium carbonate crystal precipitation

Abstract

The invention belongs to the technical field of geotechnical engineering, and particularly relates to a sandy soil solidification method based on bionic induction of calcium carbonate crystal precipitation. The sandy soil solidification method comprises the steps that S1, a prepared bionic induction calcium carbonate precipitation reagent comprises a solution A and a solution B, wherein the solution A is an amino acid-calcium chloride solution, and the solution B is a sodium carbonate solution; s2, spraying the liquid A on the surface of a to-be-reinforced target sand sample, and enabling the liquid A to automatically permeate under the action of gravity and capillary action; spraying the liquid B on the surface of a to-be-reinforced target sand sample, and automatically adding the liquid B into the to-be-reinforced target sand sample under the action of gravity and capillary action until the liquid B completely permeates into the to-be-reinforced target sand sample; the step S2.2 and the step S2.3 are taken as a cycle, and multiple cycles are carried out to complete reinforcement; and S3, the target sand sample is subjected to standing and airing, and a reinforced soil body is obtained. Sandy soil reinforcement is effectively completed through the bionic concept, the environmental influence is smaller, the mechanical property is better, and pollution is lower.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical engineering, and in particular relates to a sand solidification method based on bionic induction of calcium carbonate crystal precipitation. Background Art

[0002] Soil reinforcement is one of the most important issues in geotechnical engineering practice. Traditional soil reinforcement technology usually uses large-scale mechanical equipment or artificial synthetic materials to reinforce the soil. However, traditional soil reinforcement technology has many shortcomings: when using large-scale mechanical equipment for reinforcement, mechanical compaction and vibration require a lot of human and material resources; when using artificial synthetic materials for reinforcement, there are disadvantages such as high energy consumption, high pollution and high cost. For example, the production process of chemical materials such as cement and silicate produces a large amount of carbon dioxide and nitrogen oxide emissions.

[0003] At present, the soil reinforcement method of biological and biomimetic induced calcium carbonate precipitation has received extensive attention and research due to its green, low-carbon and environmentally friendly characteristics. The Chinese patent document with reference application number CN202011053799.2 discloses a method of using protein cementing materials to improve the mechanical properties of microbial cemented sand. Specifically, the reinforcement is achieved by using protein for regulation. This biological reinforcement method belongs to microbial induced sand reinforcement, but there are the following problems: Since the activity of microorganisms in the biological reinforcement process is easily affected by the external environment (such as temperature and pH), and the migration of microorganisms is limited by the size of soil pores and throats, the mechanical properties after reinforcement are poor; in addition, byproducts such as ammonia and nitrates will be formed during microbial reinforcement, which will cause great pollution to the atmosphere and soil.

[0004] Therefore, providing a sand solidification method that is less affected by the environment, has better mechanical properties and lower pollution is a current research and development topic. Summary of the invention

[0005] In view of the technical problems of existing sand reinforcement such as great environmental impact, poor mechanical properties and great pollution, the present invention provides a sand solidification method based on bionic induced calcium carbonate crystal precipitation.

[0006] The present invention imitates the growth process of the calcium carbonate hard shell of shellfish in nature, extracts key crystal modifier components, and uses amino acids as crystal modifiers to change the morphology and crystal form of calcium carbonate precipitation, so that the calcium carbonate precipitation can be tightly attached to the surface of sand particles through hydrogen bonds, cementing adjacent sand particles, effectively completing sand soil reinforcement, being less affected by the environment, having better mechanical properties and lower pollution.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A sand solidification method based on bionic induction of calcium carbonate crystal precipitation comprises the following steps:

[0009] S1. Biomimetic induced calcium carbonate precipitation reagent configuration

[0010] The configured biomimetic induced calcium carbonate precipitation reagent includes liquid A and liquid B: the liquid A is an amino acid-calcium chloride solution, and the liquid B is a sodium carbonate solution;

[0011] S2. Sand reinforcement

[0012] S2.1. Spray liquid A on the surface of the target sand sample to be reinforced. Liquid A automatically penetrates into the target sand sample to be reinforced by gravity and capillary action. The volume of liquid A sprayed once is 10%-12% of the volume of the target sand sample to be reinforced.

[0013] S2.2, after liquid A has completely infiltrated, liquid B is sprayed on the surface of the target sand sample to be reinforced, and liquid B automatically infiltrates the target sand sample to be reinforced by gravity and capillary action until liquid B is also completely infiltrated; the volume of liquid B sprayed once is equal to the volume of liquid A sprayed once;

[0014] S2.3, taking step S2.2 and step S2.3 as one cycle, and performing multiple cycles; during the cycle, liquid A acts as an organic template for biomimetic induction of calcium carbonate precipitation, and undergoes double decomposition reaction with liquid B to form amino acid-modified calcium carbonate precipitate; then the amino acid-modified calcium carbonate precipitate forms hydrogen bonds with the silanol groups generated on the surface of the sand through the carboxyl groups and carbonate groups of the amino acids to cement adjacent sand particles, thereby completing reinforcement;

[0015] S3, post-processing

[0016] After step S2, the target sand sample to be reinforced is left to stand and dry to obtain reinforced sand soil.

[0017] It is further defined that in step S1, the preparation process of liquid A is:

[0018] SA1. Dissolve the amino acid in water, stir and add sodium hydroxide to mix until the mixed solution becomes alkaline;

[0019] SA2. Add anhydrous calcium chloride to the alkaline mixed solution and stir evenly to obtain liquid A; the molar ratio of water, anhydrous calcium chloride and amino acid is 1:1:(2-4):(1-3).

[0020] In a further embodiment, the amino acid is aspartic acid, glutamic acid, threonine or arginine.

[0021] It is further defined that the chiral configuration of the amino acid is L-type or D-type.

[0022] It is further defined that in the SA1, the stirring speed is 1500r / min-2000r / min, and the stirring time is 45min-60min.

[0023] It is further defined that in the SA2, the stirring speed is 1000r / min-1200r / min, and the stirring time is 30min.

[0024] It is further defined that in step S1, the preparation process of liquid B is: anhydrous sodium carbonate and water are mixed in a molar ratio of (2-4): 1:1, and stirred evenly.

[0025] It is further defined that the stirring speed is 1000r / min-1200r / min, and the stirring time is 30min.

[0026] It is further defined that in step S2.3, the multiple cycles are 10 to 20 times.

[0027] It is further defined that in step S3, ventilation and air-drying specifically refers to: ventilation and air-drying at room temperature for 5 to 7 days.

[0028] The mechanism of the method for solidifying sandy soil of the present invention is as follows: the amino acid in liquid A acts as a weak electrolyte, which will ionize in the solution to generate anions, and then the dicarboxyl groups on the anions can provide suitable binding sites for calcium ions, thereby forming an amino acid-calcium complex as an organic template for inducing calcium carbonate precipitation; when sodium carbonate solution (liquid B) is added to liquid A, the sodium carbonate is hydrolyzed into carbonate anions and bicarbonate anions, which will undergo a double decomposition reaction with the amino acid-calcium complex, and the carbonate will replace the amino acid anions around the calcium ions to form a modified calcium carbonate precipitate. At this time, due to the regulatory effect of the amino acid, the calcium carbonate will exist in the form of vaterite or aragonite crystal nuclei, rather than the traditional calcite-type crystal nuclei (see Figure 1 ). During the bonding process of liquid A, liquid B and sand, a large number of silanol groups will be generated on the surface of the sand due to the exposure of the sand to the air. The amino acid-modified calcium carbonate precipitate will form hydrogen bonds with the silanol groups on the surface of the sand particles through the carboxyl and carbonate groups of the amino acids, thereby bonding with the sand. Ultimately, the amino acid-modified calcium carbonate precipitate will tightly adhere to the surface of the sand particles and the gaps between the sand particles, and further tightly bond the adjacent sand particles together to form a sand block with higher strength.

[0029] Based on the above principles, compared with the prior art, the present invention has the following advantages:

[0030] 1. The present invention introduces the bionic concept into the field of calcium carbonate-induced sand reinforcement for the first time. By simulating the amino acids secreted by shellfish and some microorganisms in nature, the calcium carbonate crystals are modified to form a nano-layered structure, which greatly increases the shell strength. By introducing this bionic concept and process into the field of geotechnical engineering, amino acids are used as crystal modifiers to change the morphology and crystal form of calcium carbonate precipitation, so that the calcium carbonate precipitation can be tightly attached to the surface of the sand particles through hydrogen bonds, and the adjacent sand particles are cemented together, effectively completing the sand reinforcement. The crystal modifier used is less affected by the external environment such as temperature and pH, has a wider range of applications, and has a more stable soil reinforcement effect.

[0031] 2. Compared with the traditional microbial induced calcium carbonate precipitation reinforcement process for sandy soil, the present invention uses amino acids as crystal modifiers, which are smaller in size, more stable in performance, not affected by the pore throat size of the soil, and can flow freely between soil particles. The reinforcement effect is more uniform, and it effectively avoids the shortcomings of microorganisms being unable to penetrate into the fine sand due to volume collision and being easily disturbed by the external environment.

[0032] 3. In the sand reinforcement of the present invention, the process by-product is sodium chloride, which is non-toxic and harmless to the environment and is more environmentally friendly.

[0033] 4. In the present invention, by spraying the bionic induced calcium carbonate precipitation reagent on the surface of the target sand sample to be reinforced, both liquid A and liquid B automatically penetrate into the target sand sample by gravity and capillary action, without the need to use other equipment such as peristaltic pumps to assist in the operation. The process flow is simpler, the construction cost is lower, and the application scenarios are wider.

[0034] 5. Mechanical tests have shown that the bionic induced calcium carbonate precipitation soil reinforcement method of the present invention can significantly improve the unconfined compressive strength, shear strength and splitting strength of sand, and greatly improve the mechanical properties of the target sand. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The electron microscope scanning images are before and after sand modification; among them: (a)-(c) unmodified cubic calcite-type calcium carbonate precipitates (green) and sand (purple); (d)-(f) are ellipsoidal vaterite and aragonite-type calcium carbonate precipitates and sand after amino acid modification. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is now further described in conjunction with the embodiments and test data, but the present invention is not limited to the following implementation scenarios, and the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0037] A sand solidification method based on bionic induction of calcium carbonate crystal precipitation comprises the following steps:

[0038] S1. Biomimetic induced calcium carbonate precipitation reagent configuration

[0039] The configured biomimetic induced calcium carbonate precipitation reagent includes liquid A and liquid B: liquid A is an amino acid-calcium chloride solution, and liquid B is a sodium carbonate solution.

[0040] In step S1, the preparation process of liquid A is:

[0041] SA1. Dissolve the amino acid in water, stir and add sodium hydroxide to mix until the mixed solution is alkaline; the stirring speed is 1500r / min-2000r / min, and the stirring time is 45min-60min.

[0042] SA2. Add anhydrous calcium chloride to the above alkaline mixed solution and stir evenly to obtain liquid A; the stirring speed is 1000r / min-1200r / min, and the stirring time is 30min.

[0043] In the present invention, the molar ratio of water, anhydrous calcium chloride and amino acid is 1:1:(2-4):(1-3).

[0044] Preferably, the molar ratio of water, anhydrous calcium chloride and amino acid is 111:2:1, 111:3:1, 111:4:1, 111:2:2, 111:3:2, 111:4:2, 111:2:3, 111:3:3 or 111:4:3.

[0045] Preferably, the amino acid is aspartic acid, glutamic acid, threonine or arginine. The amino acid is acidic, neutral or basic.

[0046] Preferably, the chiral configuration of the amino acid is L-type or D-type.

[0047] The preparation process of liquid B is as follows: anhydrous sodium carbonate and water are mixed in a molar ratio of (2-4): 1:1, and stirred evenly. The stirring speed is 1000r / min-1200r / min, and the stirring time is 30min.

[0048] Preferably, the molar ratio of anhydrous sodium carbonate to water is 2:111, 3:111 or 4:111.

[0049] S2. Sand reinforcement

[0050] S2.1. Spray liquid A on the surface of the target sand sample to be reinforced. Liquid A automatically penetrates into the target sand sample to be reinforced by gravity and capillary action. The volume of liquid A sprayed once is 10%-12% of the volume of the target sand sample to be reinforced.

[0051] S2.2. After liquid A has completely penetrated, liquid B is sprayed on the surface of the target sand sample to be reinforced. Liquid B automatically penetrates into the target sand sample to be reinforced through gravity and capillary action until liquid B has also completely penetrated. The volume of liquid B sprayed once is equal to the volume of liquid A sprayed once.

[0052] Preferably, the volume of liquid A sprayed once is 10%, 10.5%, 11%, 11.5% or 12% of the volume of the target sand sample to be consolidated.

[0053] S2.3. Take steps S2.2 and S2.3 as one cycle, and perform multiple cycles to complete the reinforcement.

[0054] In the present invention, in step 2.3, the multiple cycles are 10 to 20 times. Preferably, the multiple cycles are 10, 12, 14, 15, 16, 18 or 20 times.

[0055] The innovation of the present invention lies in that, in each cycle, liquid A acts as an organic template for biomimetic induction of calcium carbonate precipitation, and undergoes a double decomposition reaction with liquid B to form an amino acid-modified calcium carbonate precipitate; then the amino acid-modified calcium carbonate precipitate forms hydrogen bonds with the silanol groups generated on the surface of the sand through the carboxyl groups and carbonate groups of the amino acids to cement adjacent sand particles, thereby completing the reinforcement.

[0056] S3, post-processing

[0057] After step S2, the target sand sample to be reinforced is left to stand and air-dried to obtain reinforced sand soil. In step S3 of the present invention, ventilation and air-drying specifically includes: ventilation and air-drying at room temperature for 5 to 7 days.

[0058] The advantages of the sand reinforcement method of the present invention are described below through specific embodiments.

[0059] It should be noted that, unless otherwise specified, the chemicals, reagents, etc. used in the following examples are all conventional commercially available products in the art.

[0060] It should be noted that, unless otherwise specified, the chemical operations used in the following examples are all conventional operations in the art. For example, the temperature in the solution preparation is performed at room temperature unless otherwise specified.

[0061] Example 1

[0062] In this embodiment, the island reef sand is reinforced by bionic induction of calcium carbonate crystal precipitation.

[0063] The sand solidification method based on bionic induction of calcium carbonate crystal precipitation provided in this embodiment comprises the following steps:

[0064] S1. Solution preparation

[0065] 2 parts of arginine were weighed and dissolved in 111 parts of deionized water at room temperature, and stirred at 2000 r / min for 45 min using a magnetic stirrer. 2 parts of anhydrous calcium chloride were weighed and dissolved in the above solution at room temperature, and stirred at 1200 r / min for 30 min using a magnetic stirrer to obtain a colorless, uniform and transparent solution, i.e., solution A.

[0066] At room temperature, 2 parts of anhydrous sodium carbonate were dissolved in 111 parts of deionized water, and stirred at a speed of 1200 r / min using a magnetic stirrer for 30 minutes to obtain a colorless, uniform, transparent solution, i.e., solution B.

[0067] In this embodiment, "parts" refers to molar parts. Therefore, after weighing the raw materials according to the above molar parts, the molar ratio of deionized water, arginine and anhydrous calcium chloride is 111:2:2; the molar ratio of deionized water and anhydrous sodium carbonate is 111:2.

[0068] In this embodiment, the arginine is food grade L-chirality arginine.

[0069] In this embodiment, the molar percentages of the raw materials in liquid A are: 96.52% deionized water, 1.74% anhydrous calcium chloride, and 1.74% arginine.

[0070] In this embodiment, the molar percentages of the raw materials in liquid B are: 98.23% deionized water and 1.77% anhydrous sodium carbonate.

[0071] In this embodiment, the prepared liquid A and liquid B are used as bionic induced calcium carbonate precipitation reagents to reinforce sand.

[0072] S2. Sand reinforcement

[0073] Liquid A is measured according to 11.5% of the target sand volume to be reinforced, and sprayed evenly on the sand surface. After Liquid A completely penetrates into the sand through gravity and capillary action and there is no residue on the surface, spray the same volume of Liquid B on the sand surface; after Liquid B completely penetrates into the sand through gravity and capillary action and there is no residue on the surface, the next round of spraying cycle is carried out. Liquid A is sprayed first, and then Liquid B is sprayed last. Spraying Liquid A once and Liquid B once is considered a spraying cycle, and a total of 15 cycles are carried out.

[0074] In each cycle, liquid A acts as an organic template for biomimetic-induced calcium carbonate precipitation, and undergoes a double decomposition reaction with liquid B to form an amino acid-modified calcium carbonate precipitate; then the amino acid-modified calcium carbonate precipitate forms hydrogen bonds with the silanol groups generated on the surface of the sand through the carboxyl and carbonate groups of the amino acids to bond the adjacent sand particles and complete the reinforcement.

[0075] In this embodiment, the target sand gradation to be reinforced is shown in Table 1.

[0076] Table 1 Grading results of target sand in Example 1

[0077]

[0078] S3, post-processing

[0079] After the spraying cycle is completed, wait for the sand to dry naturally. Natural drying is achieved by ventilating and drying at room temperature for 7 days.

[0080] In this embodiment, the sandy soil reinforced by the bionic induced calcium carbonate precipitation method is obtained after drying, and the next step of mechanical property testing is carried out.

[0081] From the reinforced soil, a sandy soil cylinder with a diameter of 35 mm and a height of 80 mm (referred to as reinforced sandy soil A) was taken for mechanical property tests, including unconfined compression test, shear test and splitting test; and unreinforced sandy soil was taken for comparison in the same way. The test results are shown in Table 2.

[0082] Table 2 Mechanical properties of unreinforced and reinforced sand in Example 1

[0083] type Unconfined compressive strength (MPa) Shear strength(Kpa) Splitting strength(Kpa) Unreinforced sand 1.31 172.7 13.2 Reinforced sand A 13.38 3629.1 1782.8

[0084] It can be seen from the above table that after the reinforcement method of this embodiment, the unconfined compressive strength, shear strength and splitting strength of the sand are increased by 8.92 times, 21.01 times and 135.06 times respectively. It shows that the bionic induced calcium carbonate crystal precipitation and solidification method of this embodiment can make the modified calcium carbonate crystals precipitate in the pores between the sand particles by simulating biomineralization, play a filling role and bond the adjacent sand particles together to form a dense skeleton structure, which can greatly improve the unconfined compressive strength, shear strength and splitting strength of the sand, and the solidified sand has strong mechanical properties.

[0085] Example 2

[0086] In this embodiment, the island reef sand is reinforced by bionic induction of calcium carbonate crystal precipitation.

[0087] The sand solidification method based on bionic induction of calcium carbonate crystal precipitation provided in this embodiment comprises the following steps:

[0088] S1. Solution preparation

[0089] 1 part of aspartic acid was measured and dissolved in 111 parts of deionized water at room temperature, and stirred at 1500 r / min for 60 min using a magnetic stirrer, and 1 part of anhydrous sodium hydroxide was added in small amounts several times during the stirring process to make the pH of the solution reach about 10. 2 parts of anhydrous calcium chloride were measured and dissolved in the above solution at room temperature, and stirred at 1000 r / min for 30 min using a magnetic stirrer to obtain a colorless, uniform and transparent solution, i.e., liquid A.

[0090] At room temperature, 2 parts of anhydrous sodium carbonate were dissolved in 111 parts of deionized water, and stirred at a speed of 1000 r / min for 30 min using a magnetic stirrer to obtain a colorless, uniform, transparent solution, i.e., solution B.

[0091] In this embodiment, "parts" refers to molar parts. Therefore, after weighing the raw materials according to the above molar parts, the molar ratio of deionized water, aspartic acid and anhydrous calcium chloride is 111:1:2; the molar ratio of deionized water and anhydrous sodium carbonate is 111:2.

[0092] The aspartic acid is food grade L-chirality aspartic acid.

[0093] In this embodiment, the molar percentages of the raw materials in liquid A are: 97.37% deionized water, 1.75% anhydrous calcium chloride, and 0.88% aspartic acid.

[0094] In this embodiment, the molar percentages of the raw materials in liquid B are: 98.23% deionized water and 1.77% anhydrous sodium carbonate.

[0095] In this embodiment, the prepared liquid A and liquid B are used as bionic induced calcium carbonate precipitation reagents to reinforce sand.

[0096] S2. Sand reinforcement

[0097] Liquid A was measured according to 11.5% of the volume of the target sand to be reinforced, and was evenly sprayed on the surface of the target sand to be reinforced. After liquid A completely penetrated into the sand by gravity and capillary action and no residue was left on the surface, the same volume of liquid B was sprayed on the surface of the sand. After solution B completely penetrated into the sand by gravity and capillary action and no residue was left on the surface, the next spraying cycle was carried out. Liquid A was sprayed first, and liquid B was sprayed last. Spraying liquid A once and liquid B once was considered a spraying cycle, and a total of 15 cycles were carried out.

[0098] In each cycle, liquid A acts as an organic template for biomimetic-induced calcium carbonate precipitation, and undergoes a double decomposition reaction with liquid B to form an amino acid-modified calcium carbonate precipitate; then the amino acid-modified calcium carbonate precipitate forms hydrogen bonds with the silanol groups generated on the surface of the sand through the carboxyl and carbonate groups of the amino acids to bond the adjacent sand particles and complete the reinforcement.

[0099] In this embodiment, the target sand gradation to be reinforced is shown in Table 3.

[0100] Table 3 Grading results of target sand in Example 2

[0101]

[0102] S3, post-processing

[0103] After the spraying cycle is completed, wait for the sand to dry naturally. Natural drying is achieved by ventilating and drying at room temperature for 5 days.

[0104] In this embodiment, after drying, the soil body reinforced by the bionic induced calcium carbonate precipitation method is obtained, and the next step of mechanical property testing is carried out.

[0105] From the reinforced soil, a sandy soil cylinder with a diameter of 35 mm and a height of 80 mm (referred to as reinforced sandy soil A) was taken for mechanical property tests, including unconfined compression test, shear test and splitting test; and unreinforced sandy soil was taken for comparison in the same way. The test results are shown in Table 4.

[0106] Table 4 Mechanical properties of unreinforced and reinforced sand in Example 2

[0107] type Unconfined compressive strength (MPa) Shear strength(Kpa) Splitting strength(Kpa) Unreinforced sand 1.06 121.2 7.9 Reinforced sand A 10.21 2688.6 1295.6

[0108] It can be seen from the above table that after the reinforcement method of this embodiment, the unconfined compressive strength, shear strength and splitting strength of the sand are increased by 9.63 times, 22.18 times and 164 times respectively. It shows that the sand is solidified by the biomimetic induced calcium carbonate crystal precipitation method, and the modified calcium carbonate crystals can be precipitated in the pores between the sand particles by simulating biomineralization, playing a filling role and bonding adjacent sand particles together to form a dense skeleton structure, which can greatly improve the unconfined compressive strength, shear strength and splitting strength of the sand, and the solidified sand has strong mechanical properties.

[0109] In addition, referring to the mechanical properties of sand before and after reinforcement in Table 1 and Table 2, it can be found that the mechanical properties of sand can be greatly improved by the method of the present invention compared with that of unreinforced. However, it can also be seen that the improvement in the mechanical properties of Example 2 is slightly higher than the improvement in the mechanical properties of sand before and after reinforcement in Example 1, which indicates that the cementing ability of calcium carbonate crystals modified with aspartic acid is stronger than that of calcium carbonate crystals modified with arginine. In this way, in actual use, in construction occasions with higher requirements for mechanical properties, aspartic acid can be preferentially used as a crystal modifier in the bionic induced calcium carbonate crystal precipitation sand solidification process.

[0110] The amino acids used in the above implementation are aspartic acid and arginine, and the chirality of both is L-type; when the chirality of aspartic acid and the chirality of arginine are both selected to be D-type, or when the amino acid is glutamic acid or threonine and the chirality is L-type (or D-type), the method of the present invention is used to imitate the growth process of the calcium carbonate hard shell of shellfish in nature, and amino acids are used as crystal modifiers to solidify the sand, showing the same solidification principle as Example 1 and Example 2, and the ability to improve the mechanical properties of the sand is similar to that of Example 1 or Example 2.

[0111] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sand solidification method based on bionic induction of calcium carbonate crystal precipitation, characterized in that: The following steps are involved: S1. Biomimetic induced calcium carbonate precipitation reagent configuration The configured biomimetic induced calcium carbonate precipitation reagent includes liquid A and liquid B: the liquid A is an amino acid-calcium chloride solution, and the liquid B is a sodium carbonate solution; S2. Sand reinforcement S2.

1. Spray liquid A on the surface of the target sand sample to be reinforced. Liquid A automatically penetrates into the target sand sample to be reinforced by gravity and capillary action. The volume of liquid A sprayed once is 10%-12% of the volume of the target sand sample to be reinforced. S2.2, after liquid A has completely infiltrated, liquid B is sprayed on the surface of the target sand sample to be reinforced, and liquid B automatically infiltrates the target sand sample to be reinforced by gravity and capillary action until liquid B is also completely infiltrated; the volume of liquid B sprayed once is equal to the volume of liquid A sprayed once; S2.3, taking step S2.2 and step S2.3 as one cycle, and performing multiple cycles; during the cycle, liquid A acts as an organic template for biomimetic induction of calcium carbonate precipitation, and undergoes double decomposition reaction with liquid B to form amino acid-modified calcium carbonate precipitate; then the amino acid-modified calcium carbonate precipitate forms hydrogen bonds with the silanol groups generated on the surface of the sand through the carboxyl groups and carbonate groups of the amino acids to cement adjacent sand particles, thereby completing reinforcement; S3, post-processing After step S2, the target sand sample to be reinforced is left to stand and dry to obtain reinforced sand soil.

2. The sand solidification method based on bionic induced calcium carbonate crystal precipitation according to claim 1 is characterized in that: In step S1, the preparation process of liquid A is: SA1. Dissolve the amino acid in water, stir and add sodium hydroxide to mix until the mixed solution becomes alkaline; SA2. Add anhydrous calcium chloride to the alkaline mixed solution and stir evenly to obtain liquid A; the molar ratio of water, anhydrous calcium chloride and amino acid is 1:1:(2-4):(1-3).

3. The sand solidification method based on bionic induced calcium carbonate crystal precipitation according to claim 2 is characterized in that: The amino acid is aspartic acid, glutamic acid, threonine or arginine.

4. The sand solidification method based on bionic induced calcium carbonate crystal precipitation according to claim 2 is characterized in that: The chiral structure of amino acids is either L or D.

5. The sand solidification method based on bionic induced calcium carbonate crystal precipitation according to claim 2 is characterized in that: In the SA1, the stirring speed is 1500r / min-2000r / min, and the stirring time is 45min-60min.

6. The sand solidification method based on bionic induced calcium carbonate crystal precipitation according to claim 2 is characterized in that: In the SA2, the stirring speed is 1000r / min-1200r / min, and the stirring time is 30min.

7. The sand solidification method based on bionic induction of calcium carbonate crystal precipitation according to claim 1 is characterized in that: In step S1, the preparation process of liquid B is as follows: anhydrous sodium carbonate and water are mixed in a molar ratio of (2-4): 1:1, and stirred evenly.

8. The sand solidification method based on bionic induction of calcium carbonate crystal precipitation according to claim 7 is characterized in that: The stirring speed is 1000r / min-1200r / min, and the stirring time is 30min.

9. The sand solidification method based on bionic induction of calcium carbonate crystal precipitation according to claim 1, characterized in that: In step S2.3, the multiple cycles are 10 to 20 times.

10. The sand solidification method based on bionic induction of calcium carbonate crystal precipitation according to claim 1, characterized in that: In the step S3, ventilation and drying specifically includes: ventilation and drying at room temperature for 5 to 7 days.

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