Soil solidification complexing agent containing biological enzyme as well as preparation method and application of soil solidification complexing agent

Abstract

The invention belongs to the technical field of soil solidification, and particularly relates to a biological enzyme-containing soil solidification complexing agent as well as a preparation method and application thereof. Comprising a composite biological enzyme, an inorganic nano-composite, an inorganic gel substance, an organic enhancer, a penetrating agent, a pH buffer agent, a water reducing agent and an exciting agent, and the preparation method comprises the following steps: firstly, vacuumizing the inorganic nano-composite and the composite biological enzyme, and then uniformly stirring steel slag micro-powder, slag and desulfurized gypsum; mixing the organic reinforcer with water, heating in a water bath, uniformly stirring, and finally mixing the three substances with other auxiliaries, and granulating to obtain the soil solidification complexing agent containing the biological enzyme. The composite bio-enzyme destroys the double electric layer structure of soil and reduces the hydrophilicity to form a waterproof layer; the nano inorganic compound is used for loading enzyme molecules, the enzyme loading rate is improved by combining a negative pressure impregnation process, the slow release effect is achieved, and the porosity is reduced and the compressive strength is improved by the cooperation of the inorganic gel and the organic reinforcer paste.

Description

Technical Field

[0001] This application belongs to the technical field of soil solidification, and specifically relates to a soil solidification composite agent containing bioenzymes, its preparation method and application. Background Art

[0002] Among the highways in our country, the proportion of county and township roads and rural access roads with low grades exceeds 60%, becoming an important carrier to support regional economic development. These roads play an irreplaceable role in promoting the circulation of urban and rural materials and improving people's livelihood, but at the same time, they also face major technical challenges in subgrade treatment under special geological conditions. In road engineering practice, there are significant technical bottlenecks in traditional subgrade improvement materials. Taking lignin as an example, the functional groups such as phenylpropane units, hydroxyl groups, and methoxy groups contained in its molecular structure present a complex three-dimensional network structure, resulting in problems such as uneven molecular weight distribution and poor accessibility of reaction sites in the material. In actual engineering, phenomena such as incomplete curing reactions and large discreteness of modification effects often occur. For soils with relatively high water content, although slaked lime can reduce the liquid limit through ion exchange, its calcium ion release rate is slow, and overdosage addition is required to meet the compaction requirements, resulting in poor economy and easy occurrence of mixing segregation. Although quicklime has the characteristic of rapid water absorption, its violent hydration heat release reaction will shorten the construction window period, and it is difficult to accurately control the reaction process under complex working conditions. Although fly ash materials have a microaggregate effect, their pozzolanic activity index is generally low, making it difficult to meet the strength requirements of heavy-duty traffic pavements. Moreover, the application of these traditional raw materials also has the problem of increasing economic costs. Against this background, bioenzyme soil solidification technology has attracted extensive attention in the academic community due to its environmentally friendly characteristics. Such new curing agents are mainly derived from plant cell extracts, and active ingredients such as protease and lipase prepared through biological fermentation processes can catalyze the directional conversion of soil organic matter under normal temperature conditions. Its mechanism of action is as follows: The soil solidification agent made from living plant cells has good consolidation and stability. Through its catalytic action, a large number of organic macromolecules in clay can combine to form intermediate reaction enzymes. This substance is adsorbed by clay ions and replaces them, thereby weakening the water absorption capacity of soil particles, reducing their hydrophilicity, creating a shielding effect on water, forming a waterproof soil layer. Through compaction, the soil loses its ability to absorb water again after compaction, and even if water is added again after compaction, it will not affect the mechanical efficiency of the compacted soil mass. The reaction is at the micron level, and the presence of wet substances and fine particles the size of clay is essential. By increasing the density of the soil, improving the strength and stability of the soil, the expansibility of the soil can be effectively reduced, and the liquefaction phenomenon caused by vehicle dynamic loads in silty roads can be effectively improved, extending the service life of the road.

[0003] Researchers in developed countries have been intensively studying the technology of using bioenzymes to reinforce soil since the 1980s. They have successively developed various soil stabilizer materials such as Conaidsuper, Terrazyme, Permazyme, and Roadbond enzymes. The Terrazyme series of products developed by Enzyme Solutions in the United States have been verified in more than 50 countries. Data shows that it can increase the elastic modulus of the roadbed by more than 300%. Compared with the long research and application history in developed countries such as Europe and the United States, the research in China started late and the time is short, and the research on new soil stabilizers needs to be strengthened. Although the soil solidification technology with enzymes has many advantages, it still faces some challenges in practical applications. The most important one is the problem of maintaining the activity of enzymes. When enzymes exert catalytic activity, they have high requirements for external environments such as pH. Directly mixing with soil is likely to cause enzyme inactivation and thus lead to poor solidification effect.

[0004] The technical solution disclosed in the patent with the publication number CN118755481A discloses a soil solidification material based on native enzyme-modified nanoparticles and solid waste. The soil solidification material includes the following components in parts by weight: 8-12 parts of industrial solid waste, 2-6 parts of activator, 0-7 parts of native enzyme, and 0-2 parts of nanomaterial. The native enzyme and nanoparticles synergistically solidify the soil body. Both can not only play their own solidification roles, but also the native enzyme can modify the nanoparticles to improve the dispersibility of the nanoparticles and the filling effect. The Chinese patent with the publication number CN113666705B discloses a soil solidification material based on solid waste and bioenzyme and its preparation method. This technical solution uses a soil solidification material based on solid waste and bioenzyme, including recycled aggregate, steel slag, industrial waste gypsum, high-calcium fly ash, inorganic adsorbent, organic adsorbent, and bioenzyme. Through treatment methods such as microwave radiation, ultrasonic oscillation, and calcination, a highly efficient powdery solidification material is formed, significantly improving the solidification strength and compactness of the soil. In the above two technical solutions, only the bioenzyme and nanoparticles are mechanically mixed, and there is no way to solve the problem that the enzyme is easily inactivated in the soil.

[0005] In view of the problem that the enzyme in the soil solidifier containing bioenzyme is easily inactivated in the existing technology, which easily leads to the shortening of the road life, it is urgent to propose a soil solidification composite agent containing bioenzyme, its preparation method and application to improve the drawbacks in the existing technology. Summary of the Invention

[0006] In view of the problem that the enzyme in the soil solidifier containing bioenzyme is easily inactivated in the existing technology, which easily leads to the shortening of the road life, the present application proposes a soil solidification composite agent containing bioenzyme, its preparation method and application. The technical solution of the present application is as follows:

[0007] On the one hand, the present application provides a soil solidification composite agent containing bioenzymes, which comprises the following components in parts by weight: 0.5 - 3 parts of composite bioenzymes, 10 - 20 parts of inorganic nano - composites, 30 - 50 parts of inorganic gels, 10 - 25 parts of organic reinforcements, 3 - 5 parts of penetrants, 0.5 - 3 parts of pH buffers, 3 - 5 parts of water - reducing agents, and 10 - 20 parts of activators;

[0008] The composite bioenzymes are a ternary composite enzyme of protease, lipase, and cellulase; the inorganic nano - composite is a nano - compound with a tubular structure and a layered structure.

[0009] Preferably, the mass ratio of protease, lipase, and cellulase is 1:(0.3 - 0.8):(0.5 - 1.2).

[0010] Preferably, the protease is subtilisin, and the lipase is Pseudomonas fluorescens lipase subtilisin.

[0011] Preferably, the inorganic nano - material with a tubular structure is silica, the inorganic nano - material with a layered structure is montmorillonite, and the mass ratio of silica to montmorillonite is 6:4.

[0012] Preferably, the inorganic gel system is a mixture of steel slag powder, slag, and desulfurized gypsum in a mass ratio of 30:54:16.

[0013] Preferably, the organic reinforcement system is a mixture of sodium alginate and sodium lignosulfonate in a mass ratio of 7:3.

[0014] Preferably, the penetrant is fatty alcohol polyoxyethylene ether, the pH buffer is sodium dihydrogen phosphate, the water - reducing agent is a polycarboxylate - based water - reducing agent, and the activator is a mixture of sodium silicate and calcium hydroxide in a mass ratio of 3:1.

[0015] On the second hand, the present application provides a preparation method of a soil solidification composite agent containing bioenzymes, which comprises the following steps:

[0016] Step S1. The inorganic nano - composite and the composite bioenzymes are impregnated at −0.08 to −0.1 MPa for 30 min, and then freeze - dried at −30 °C for 10 hours to obtain a first mixture;

[0017] Step S2. The steel slag powder, slag, and desulfurized gypsum are added to a dry powder mixer in proportion and stirred evenly to obtain a second mixture;

[0018] Step S3. The organic reinforcement is mixed with water in a mass ratio of 1:(1 - 2), and stirred in a 60 °C water bath until completely dissolved to obtain a mixed solution;

[0019] Step S4. Mix the first mixture, the second mixture, the mixed solution, the penetrant, the pH buffer, the water reducer and the activator evenly, and finally granulate and dry at 50 °C until the moisture content is lower than 1% to obtain a bio-enzyme-containing soil solidification composite agent.

[0020] Thirdly, the present application provides an application of a bio-enzyme-containing soil solidification composite agent for soil solidification. The specific operation is as follows: Mix the bio-enzyme-containing soil solidification composite agent evenly with soft soil having a moisture content greater than 40%, let it stand for 2-3 h, and then supplement 0.5-1% CaCl2 solution; finally, cover it with an oxygen-permeable membrane and cure for 6-8 h.

[0021] Preferably, the addition amount of the bio-enzyme-containing soil solidification composite agent is 5-15% of the mass of the soft soil, the addition amount of the CaCl2 solution is 0.5-1% of the mass of the soft soil, and the concentration of CaCl2 is 3 mol / L.

[0022] The beneficial effects of the present application are as follows:

[0023] (1) The protease, lipase and cellulase in the present application are compounded in a ratio of 1:(0.3-0.8):(0.5-1.2) to form a synergistic catalytic network. Subtilisin degrades proteinaceous organic matter in the soil, destroys the organic coating on the surface of clay particles, and exposes the mineral active sites. Pseudomonas fluorescens lipase decomposes lipid substances, reduces the water adsorption capacity of soil organic matter, and cellulase decomposes plant fiber residues, releasing bound clay particles and promoting physical contact between particles. The three work together to break the soil double-layer structure, reduce hydrophilicity, and form a waterproof soil layer. Under negative pressure impregnation conditions in the present application, enzyme molecules are embedded in nano-pores, improving the enzyme molecule loading rate while maintaining the enzyme activity. Based on the slow-release performance of nano-materials, enzymes can be released for a long time, extending the service life of the roadbed. Tubular silica provides a high specific surface area, adsorbs enzyme molecules through capillary action to prevent enzyme inactivation, and layered montmorillonite fixes enzyme molecules through ion exchange. Its interlayer swelling property allows the exposure of enzyme active centers, improving the catalytic efficiency.

[0024] (2) The interpenetrating network of the inorganic gel and the organic enhancer in the present application, the steel slag-slag-desulfurized gypsum ternary cementitious system, the steel slag powder provides Ca 2+ and SiO4 2- , initially hydrates to form C-S-H gel nuclei. The slag releases Al 3+ under the sulfate excitation of desulfurized gypsum and forms ettringite with Ca 2+ , filling the pores. Sodium alginate forms a structural gel with Ca 2+ from the subsequent CaCl2 solution, further filling the voids and improving toughness. Lignosulfonate degrades into humic acid, adsorbs clay particles through π-π bonds, and simultaneously releases negatively charged groups to enhance particle repulsion. The two work together to reduce the porosity and improve the strength.

[0025] (3) The fatty alcohol polyoxyethylene ether of the present application rapidly wets the soil through dynamic desorption, reduces the surface tension, and promotes the penetration of nanoparticles. The sodium dihydrogen phosphate buffer keeps the enzyme activity within the optimal range and delays the premature hardening of the gelling system. The polycarboxylate superplasticizer disperses the gelling particles through steric hindrance effect and reduces the water-cement ratio. The sodium silicate-calcium hydroxide activator provides an alkaline environment to activate the slag vitreous body, and at the same time, the silicate radical reacts with Ca 2+ to form a calcium silicate skeleton.

[0026] (4) In the application process of the present application, the enzymatic reaction and ionic crosslinking control the time sequence. First, let it stand for 2 to 3 hours to allow the enzyme to fully degrade the organic matter, and at this time, the soil water content decreases. After adding the CaCl2 solution, sodium alginate and Ca 2+ form a gel network, and the compressive strength is improved. Covering the oxygen-permeable membrane balances the aerobic activity of the enzyme and the humidity required for the gelling reaction, and avoids causing enzyme inactivation.

[0027] In summary, the soil solidification composite agent containing bioenzymes provided by the present application realizes the improvement of soil solidification efficiency and long-term stability through multi-level coordination. Detailed Embodiments

[0028] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following, in combination with preferred preparation examples, details the specific embodiments, structures, features and their effects according to the present invention as follows.

[0029] Preparation Example 1

[0030] This preparation example provides a preparation method of a soil solidification composite agent containing bioenzymes, which is as follows:

[0031] The ratio of the soil solidification composite agent containing bioenzymes is specifically as follows:

[0032] 1 part of composite bioenzyme: among which, the mass ratio of subtilisin, Pseudomonas fluorescens lipase and cellulase is 1:0.5:0.9 and mixed;

[0033] 15 parts of inorganic nanocomposite: obtained by mixing tubular silica and layered montmorillonite in a mass ratio of 6:4;

[0034] 45 parts of inorganic gel: obtained by mixing steel slag powder, slag and desulfurized gypsum in a mass ratio of 30:54:16;

[0035] 15 parts of organic enhancer: obtained by mixing sodium alginate and sodium lignosulfonate in a mass ratio of 7:3;

[0036] 4 parts of penetrant: fatty alcohol polyoxyethylene ether;

[0037] 1.5 parts of pH buffer: sodium dihydrogen phosphate;

[0038] 4 parts of water reducer polycarboxylic acid;

[0039] 14.5 parts of activator: obtained by mixing sodium silicate and calcium hydroxide in a mass ratio of 3:1.

[0040] The preparation steps are as follows:

[0041] Step S1: Mix the composite bio-enzyme and the inorganic nano-composite and place them in a vacuum impregnation tank. Adjust the vacuum degree to -0.08 MPa and impregnate for 30 minutes. Transfer to a freeze dryer and dry at -30 °C for 10 hours to obtain the first mixture;

[0042] Step S2: Add steel slag powder, slag, and desulfurized gypsum to a dry powder mixer and stir at a speed of 200 rpm for 20 minutes to obtain the second mixture;

[0043] Step S3: Mix sodium alginate and sodium lignosulfonate, add deionized water (the mass ratio of the sum of the masses of sodium alginate and sodium lignosulfonate to the mass of deionized water is 1:1), and stir at 500 rpm in a 60 °C water bath until completely dissolved to obtain a mixed solution;

[0044] Step S4: Add the first mixture, the second mixture, the mixed solution, fatty alcohol polyoxyethylene ether, sodium dihydrogen phosphate, polycarboxylic acid, and activator to a mixer, stir at 500 rpm for 30 min, and finally form by an extrusion granulator (pore diameter 2 mm), and dry at 50 °C hot air until the moisture content is 0.2% to obtain a bio-enzyme-containing soil solidification composite agent with a particle size of 1 - 3 mm.

[0045] Preparation Example 2

[0046] This preparation example provides a preparation method of a bio-enzyme-containing soil solidification composite agent, which is specifically as follows:

[0047] The ratio of the bio-enzyme-containing soil solidification composite agent is specifically as follows:

[0048] 1.5 parts of composite bio-enzyme: obtained by mixing subtilisin, Pseudomonas fluorescens lipase, and cellulase in a mass ratio of 1:0.3:0.8;

[0049] 14 parts of inorganic nano-composite: obtained by mixing tubular silica and layered montmorillonite in a mass ratio of 6:4;

[0050] 33 parts of inorganic gel: obtained by mixing steel slag powder, slag, and desulfurized gypsum in a mass ratio of 30:54:16;

[0051] 22 parts of organic enhancer: obtained by mixing sodium alginate and sodium lignosulfonate in a mass ratio of 7:3;

[0052] 4.5 parts of penetrant: fatty alcohol polyoxyethylene ether;

[0053] 2 parts of pH buffer: sodium dihydrogen phosphate;

[0054] 4 parts of water reducer polycarboxylic acid;

[0055] 19 parts of activator: obtained by mixing sodium silicate and calcium hydroxide in a mass ratio of 3:1.

[0056] The preparation steps are as follows:

[0057] Step S1: Mix the composite bio-enzyme and the inorganic nano-composite and place them in a vacuum impregnation tank. Adjust the vacuum degree to -0.06 MPa and impregnate for 30 minutes. Transfer to a freeze dryer and dry at -30 °C for 10 hours to obtain the first mixture;

[0058] Step S2: Add steel slag powder, slag, and desulfurized gypsum to a dry powder mixer and stir at a speed of 200 rpm for 20 minutes to obtain the second mixture.

[0059] Step S3: Mix sodium alginate and sodium lignosulfonate, add deionized water (the mass ratio of the sum of the masses of sodium alginate and sodium lignosulfonate to the mass of deionized water is 1:1.2), and stir in a 60 °C water bath at 500 rpm until completely dissolved to obtain a mixed solution.

[0060] Step S4: Add the first mixture, the second mixture, the mixed solution, fatty alcohol polyoxyethylene ether, sodium dihydrogen phosphate, polycarboxylic acid, and activator to a mixer and stir at 500 rpm for 30 min. Finally, form it through an extrusion granulator (pore diameter 2 mm) and dry at 50 °C with hot air until the moisture content is 0.2% to obtain a bio-enzyme-containing soil solidification composite agent with a particle size of 1 - 3 mm.

[0061] Preparation Example 3

[0062] This preparation example provides a preparation method of a bio-enzyme-containing soil solidification composite agent, which is specifically as follows:

[0063] The ratio of the bio-enzyme-containing soil solidification composite agent is specifically as follows:

[0064] 2 parts of composite bio-enzyme: obtained by mixing subtilisin, fluorescent pseudomonas lipase, and cellulase in a mass ratio of 1:0.8:1.2;

[0065] 10 parts of inorganic nano-composite: obtained by mixing tubular silica and layered montmorillonite in a mass ratio of 6:4;

[0066] 40 parts of inorganic gel: obtained by mixing steel slag powder, slag, and desulfurized gypsum in a mass ratio of 30:54:16;

[0067] 18 parts of organic enhancer: obtained by mixing sodium alginate and sodium lignosulfonate in a mass ratio of 7:3;

[0068] 3.5 parts of penetrant: fatty alcohol polyoxyethylene ether;

[0069] 2.5 parts of pH buffer: sodium dihydrogen phosphate;

[0070] 4 parts of water reducer polycarboxylic acid;

[0071] 20 parts of activator: obtained by mixing sodium silicate and calcium hydroxide in a mass ratio of 3:1.

[0072] The preparation method is as follows:

[0073] Step S1: Mix the composite bioenzyme and the inorganic nanocomposite and place them in a vacuum impregnation tank. Adjust the vacuum degree to -0.04 MPa and impregnate for 30 minutes. Transfer to a freeze dryer and dry at -30 °C for 10 hours to obtain the first mixture;

[0074] Step S2: Add steel slag powder, slag, and desulfurized gypsum to a dry powder mixer and stir at a speed of 200 rpm for 20 minutes to obtain the second mixture.

[0075] Step S3: Mix sodium alginate and sodium lignosulfonate, add deionized water (the mass ratio of the sum of the masses of sodium alginate and sodium lignosulfonate to deionized water is 1:1.5), and stir in a 60 °C water bath at 500 rpm until completely dissolved to obtain a mixed solution.

[0076] Step S4: Add the first mixture, the second mixture, the mixed solution, fatty alcohol polyoxyethylene ether, sodium dihydrogen phosphate, polycarboxylic acid, and activator to a mixer and stir at 500 rpm for 30 min. Finally, form it through an extrusion granulator (pore diameter 2 mm) and dry in hot air at 50 °C until the moisture content is 0.2% to obtain a soil solidification composite agent containing bioenzyme, with a particle size of 1 - 3 mm.

[0077] Preparation Example 4

[0078] This preparation example provides a preparation method of a soil solidification composite agent containing bioenzyme, specifically as follows:

[0079] The ratio of the soil solidification composite agent containing bioenzyme is specifically as follows:

[0080] 0.5 part of composite bioenzyme: among them, obtained by mixing subtilisin, Pseudomonas fluorescens lipase, and cellulase in a mass ratio of 1:0.4:0.5;

[0081] 20 parts of inorganic nanocomposite: obtained by mixing tubular silica and layered montmorillonite in a mass ratio of 6:4;

[0082] 30 parts of inorganic gel: obtained by mixing steel slag powder, slag and desulfurized gypsum in a mass ratio of 30:54:16;

[0083] 25 parts of organic reinforcement: obtained by mixing sodium alginate and sodium lignosulfonate in a mass ratio of 7:3;

[0084] 3 parts of penetrant: fatty alcohol polyoxyethylene ether;

[0085] 0.5 part of pH buffer: sodium dihydrogen phosphate;

[0086] 5 parts of water reducer polycarboxylic acid;

[0087] 16 parts of activator: obtained by mixing sodium silicate and calcium hydroxide in a mass ratio of 3:1.

[0088] The preparation method is as follows:

[0089] Step S1: Mix the composite bio-enzyme and the inorganic nano-complex and place them in a vacuum impregnation tank. Adjust the vacuum degree to -0.02 MPa and impregnate for 30 minutes. Transfer to a freeze dryer and dry at -30 °C for 10 hours to obtain the first mixture;

[0090] Step S2: Add steel slag powder, slag and desulfurized gypsum to a dry powder mixer and stir at a speed of 200 rpm for 20 minutes to obtain the second mixture.

[0091] Step S3: Mix sodium alginate and sodium lignosulfonate, add deionized water (the mass ratio of the sum of the masses of sodium alginate and sodium lignosulfonate to the mass of deionized water is 1:1.8), and stir in a 60 °C water bath at 500 rpm until completely dissolved to obtain a mixed solution.

[0092] Step S4: Add the first mixture, the second mixture, the mixed solution, fatty alcohol polyoxyethylene ether, sodium dihydrogen phosphate, polycarboxylic acid and activator to a mixer, stir at 500 rpm for 30 min, and finally form by an extrusion granulator (pore diameter 2 mm), and dry at 50 °C hot air until the moisture content is 0.2%, to obtain a bio-enzyme-containing soil solidification composite agent with a particle size of 1 - 3 mm.

[0093] Preparation Example 5

[0094] This preparation example provides a preparation method of a bio-enzyme-containing soil solidification composite agent, which is specifically as follows:

[0095] The ratio of the bio-enzyme-containing soil solidification composite agent is specifically as follows:

[0096] 3 parts of composite bio-enzyme: among them, obtained by mixing subtilisin, Pseudomonas fluorescens lipase and cellulase in a mass ratio of 1:0.7:1;

[0097] 16 parts of inorganic nano - composite: obtained by mixing tubular silica and layered montmorillonite in a mass ratio of 6:4;

[0098] 50 parts of inorganic gel: obtained by mixing steel slag powder, slag and desulfurized gypsum in a mass ratio of 30:54:16;

[0099] 10 parts of organic reinforcing agent: obtained by mixing sodium alginate and sodium lignosulfonate in a mass ratio of 7:3;

[0100] 5 parts of penetrant: fatty alcohol polyoxyethylene ether;

[0101] 3 parts of pH buffer: sodium dihydrogen phosphate;

[0102] 3 parts of water - reducing agent polycarboxylic acid;

[0103] 10 parts of activator: obtained by mixing sodium silicate and calcium hydroxide in a mass ratio of 3:1.

[0104] The preparation method is as follows:

[0105] Step S1: Mix the composite bio - enzyme with the inorganic nano - composite and place it in a vacuum impregnation tank. Adjust the vacuum degree to - 0.1 MPa and impregnate for 30 minutes. Transfer it to a freeze - dryer and dry at - 30 °C for 10 hours to obtain the first mixture;

[0106] Step S2: Add steel slag powder, slag and desulfurized gypsum to a dry powder mixer and stir at a speed of 200 rpm for 20 minutes to obtain the second mixture.

[0107] Step S3: Mix sodium alginate and sodium lignosulfonate, add deionized water (the mass ratio of the sum of the masses of sodium alginate and sodium lignosulfonate to deionized water is 1:2), and stir in a 60 °C water bath at 500 rpm until completely dissolved to obtain a mixed solution.

[0108] Step S4: Add the first mixture, the second mixture, the mixed solution, fatty alcohol polyoxyethylene ether, sodium dihydrogen phosphate, polycarboxylic acid and activator to a mixer, stir at 500 rpm for 30 min, and finally form it through an extrusion granulator (pore diameter 2 mm), and dry at 50 °C hot air until the moisture content is 0.2%, to obtain the soil solidification composite agent containing bio - enzyme, with a particle size of 1 - 3 mm.

[0109] Comparative Preparation Example 1

[0110] The difference between this comparative preparation example and Preparation Example 1 is that protease is not added.

[0111] Comparative Preparation Example 2

[0112] The difference between this comparative preparation example and Preparation Example 1 is that lipase is not added.

[0113] Comparative Preparation Example 3

[0114] The difference between this comparative preparation example and Preparation Example 1 is that cellulase was not added.

[0115] Comparative Preparation Example 4

[0116] The difference between this comparative preparation example and Preparation Example 1 is that silica was not added.

[0117] Comparative Preparation Example 5

[0118] The difference between this comparative preparation example and Preparation Example 1 is that montmorillonite was not added.

[0119] Comparative Preparation Example 6

[0120] The difference between this comparative preparation example and Preparation Example 1 is that neither montmorillonite nor silica was added.

[0121] Comparative Preparation Example 7

[0122] The difference between this comparative preparation example and Preparation Example 1 is that vacuum pumping treatment was not carried out.

[0123] Comparative Preparation Example 8

[0124] The difference between this comparative preparation example and Preparation Example 1 is that sodium alginate was not added.

[0125] Comparative Preparation Example 9

[0126] The difference between this comparative preparation example and Preparation Example 1 is that sodium lignosulfonate was not added.

[0127] Comparative Preparation Example 10

[0128] The difference between this comparative preparation example and Preparation Example 1 is that neither sodium alginate nor sodium lignosulfonate was added.

[0129] Example 1

[0130] The bio-enzyme-containing soil solidification composite agent prepared in Preparation Example 1 was selected in this example.

[0131] It was mixed with soft soil with a water content of 45%. The composite agent was added at 5% of the mass of the soft soil, and a rotary tiller (rotation speed 120 rpm) was used to mix for 20 minutes. After paving, it was left standing for 2 h (ambient temperature 25 °C). A 0.5% CaCl2 solution (concentration 3 mol / L) was sprayed, and the compaction degree reached 96%. An oxygen-permeable membrane was covered, and it was cured for 7 hours. The 7-day compressive strength was detected to be 9.62 MPa and the 28-day compressive strength was 11.74 MPa, and the strength loss rate after 50 freeze-thaw cycles was 4.73%.

[0132] Example 2

[0133] In this example, the soil solidification composite agent containing bio-enzyme prepared in Preparation Example 2 was selected.

[0134] The soft soil with a water content of 45% was mixed, and the composite agent was added at 8% of the soft soil mass. A rotary tiller (rotation speed 120 rpm) was used to mix for 20 minutes. After paving, it was left to stand for 2 h (ambient temperature 25°C). A 0.6% CaCl2 solution (concentration 3 mol / L) was sprayed, the compaction degree reached 96%, an oxygen-permeable membrane was covered, and curing was carried out for 7 hours. The 7-day compressive strength was detected to be 8.94 MPa and the 28-day compressive strength was 10.79 MPa, and the strength loss rate after 50 freeze-thaw cycles was 5.88%.

[0135] Example 3

[0136] In this example, the soil solidification composite agent containing bio-enzyme prepared in Preparation Example 3 was selected.

[0137] The soft soil with a water content of 45% was mixed, and the composite agent was added at 10% of the soft soil mass. A rotary tiller (rotation speed 120 rpm) was used to mix for 20 minutes. After paving, it was left to stand for 2.5 h (ambient temperature 25°C). A 0.8% CaCl2 solution (concentration 3 mol / L) was sprayed, the compaction degree reached 96%, an oxygen-permeable membrane was covered, and curing was carried out for 7 hours. The 7-day compressive strength was detected to be 9.02 MPa and the 28-day compressive strength was 11.17 MPa, and the strength loss rate after 50 freeze-thaw cycles was 5.07%.

[0138] Example 4

[0139] In this example, the soil solidification composite agent containing bio-enzyme prepared in Preparation Example 4 was selected.

[0140] The soft soil with a water content of 45% was mixed, and the composite agent was added at 12% of the soft soil mass. A rotary tiller (rotation speed 120 rpm) was used to mix for 20 minutes. After paving, it was left to stand for 2.5 h (ambient temperature 25°C). A 0.9% CaCl2 solution (concentration 3 mol / L) was sprayed, the compaction degree reached 96%, an oxygen-permeable membrane was covered, and curing was carried out for 7 hours. The 7-day compressive strength was detected to be 8.75 MPa and the 28-day compressive strength was 9.94 MPa, and the strength loss rate after 50 freeze-thaw cycles was 6.03%.

[0141] Example 5

[0142] In this example, the soil solidification composite agent containing bio-enzyme prepared in Preparation Example 5 was selected.

[0143] Mixing soft soil with a water content of 45%, adding a compound agent at 15% of the soft soil mass, and using a rotary tiller (rotation speed 120 rpm) to mix for 20 minutes. After paving, let it stand for 3 hours (ambient temperature 25°C). Spray 1% CaCl2 solution (concentration 3 mol / L), with the compaction degree reaching 96%, cover with an oxygen-permeable membrane, and cure for 7 hours. The 7-day compressive strength is detected to be 9.17 MPa and the 28-day compressive strength is 10.97 MPa, and the strength loss rate after 50 freeze-thaw cycles is 5.95%.

[0144] Comparative Example 1

[0145] The difference between this comparative example and Example 1 is that the bio-enzyme-containing soil solidification compound agent prepared in Preparation Example 1 is selected. The 7-day compressive strength is detected to be 8.15 MPa and the 28-day compressive strength is 9.04 MPa, and the strength loss rate after 50 freeze-thaw cycles is 7.85%.

[0146] Comparative Example 2

[0147] The difference between this comparative example and Example 1 is that the bio-enzyme-containing soil solidification compound agent prepared in Preparation Example 2 is selected. The 7-day compressive strength is detected to be 7.98 MPa and the 28-day compressive strength is 8.86 MPa, and the strength loss rate after 50 freeze-thaw cycles is 7.74%.

[0148] Comparative Example 3

[0149] The difference between this comparative example and Example 1 is that the bio-enzyme-containing soil solidification compound agent prepared in Preparation Example 3 is selected. The 7-day compressive strength is detected to be 8.01 MPa and the 28-day compressive strength is 9.12 MPa, and the strength loss rate after 50 freeze-thaw cycles is 7.20%.

[0150] Comparative Example 4

[0151] The difference between this comparative example and Example 1 is that the bio-enzyme-containing soil solidification compound agent prepared in Preparation Example 4 is selected. The 7-day compressive strength is detected to be 7.24 MPa and the 28-day compressive strength is 7.96 MPa, and the strength loss rate after 50 freeze-thaw cycles is 8.11%.

[0152] Comparative Example 5

[0153] The difference between this comparative example and Example 1 is that the bio-enzyme-containing soil solidification compound agent prepared in Preparation Example 5 is selected. The 7-day compressive strength is detected to be 7.35 MPa and the 28-day compressive strength is 8.01 MPa, and the strength loss rate after 50 freeze-thaw cycles is 8.56%.

[0154] Comparative Example 6

[0155] The difference between this comparative example and Example 1 is that the soil solidification composite containing biological enzyme prepared in Preparation Example 6 is used. The compressive strength after 7 days is 6.99 MPa and after 28 days is 7.81 MPa, and the strength loss rate after 50 freeze-thaw cycles is 8.45%.

[0156] Comparative Example 7

[0157] The difference between this comparative example and Example 1 is that the soil solidification composite agent containing biological enzymes prepared in Preparation Example 7 was used. The compressive strength after 7 days and 28 days was 7.49 MPa and 7.79 MPa, respectively, and the strength loss rate after 50 freeze-thaw cycles was 8.68%.

[0158] Comparative Example 8

[0159] The difference between this comparative example and Example 1 is that the soil solidification composite agent containing biological enzymes prepared in Preparation Example 8 was used. The compressive strength after 7 days was 7.41 MPa and the compressive strength after 28 days was 8.94 MPa, and the strength loss rate after 50 freeze-thaw cycles was 7.49%.

[0160] Comparative Example 9

[0161] The difference between this comparative example and Example 1 is that the soil solidification composite agent containing biological enzymes prepared in Preparation Example 9 was used. The compressive strength after 7 days and 28 days was 7.57 MPa and 7.96 MPa, respectively, and the strength loss rate after 50 freeze-thaw cycles was 8.11%.

[0162] Comparative Example 10

[0163] The difference between this comparative example and Example 1 is that the soil solidification composite agent containing biological enzymes prepared in Preparation Example 10 was used. The compressive strength after 7 days and 28 days was 7.09 MPa and 7.81 MPa, respectively, and the strength loss rate after 50 freeze-thaw cycles was 8.37%.

[0164] By comparing Examples 1-5 and Comparative Examples 1-10, it can be seen that the preparation method of the present application can achieve a multi-stage synergistic mechanism for efficient soil stabilization. The composite biological enzyme destroys the soil's double electrical layer structure, reducing hydrophilicity to form a waterproof layer. The nano-inorganic composite loads the enzyme molecules, and the negative pressure impregnation process increases the enzyme loading rate, achieving a sustained release effect. The inorganic gel and organic reinforcement paste synergistically reduce porosity and increase compressive strength.

[0165] The above description is only a preferred preparation example of the present invention and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with a preferred preparation example, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to form equivalent preparation examples of equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes and modifications made to the above preparation examples based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A soil solidification composite agent containing bioenzymes, characterized in that, It comprises the following components in parts by weight: 0.5 - 3 parts of composite bio - enzyme, 10 - 20 parts of inorganic nano - composite; 30 - 50 parts of inorganic gel, 10 - 25 parts of organic enhancer, 3 - 5 parts of penetrant, 0.5 - 3 parts of pH buffer, 3 - 5 parts of water - reducing agent, and 10 - 20 parts of activator; The composite bio - enzyme is a ternary composite enzyme of protease, lipase and cellulase; the inorganic nano - composite is a nano - compound with tubular structure and layered structure.

2. The soil solidification composite agent containing bioenzymes according to claim 1, characterized in that, The mass ratio of the protease, lipase and cellulase is 1:(0.3 - 0.8):(0.5 - 1.2).

3. The soil solidification composite agent containing bioenzymes according to claim 1, characterized in that, The protease is subtilisin, and the lipase is Pseudomonas fluorescens lipase subtilisin.

4. A soil solidification composite agent containing biological enzymes according to claim 1, characterized in that, The inorganic nano - material with tubular structure is silica, and the inorganic nano - material with layered structure is montmorillonite. The mass ratio of silica to montmorillonite is 6:

4.

5. A soil solidification composite agent containing bioenzymes according to claim 1, characterized in that, The inorganic gel system is a mixture of steel slag powder, slag and desulfurized gypsum in a mass ratio of 30:54:

16.

6. The soil solidification composite agent containing bioenzymes according to claim 1, wherein The organic enhancement system is a mixture of sodium alginate and sodium lignosulfonate in a mass ratio of 7:

3.

7. The soil solidification composite agent containing bioenzymes according to claim 1, characterized in that The penetrant is fatty alcohol polyoxyethylene ether, the pH buffer is sodium dihydrogen phosphate, the water - reducing agent is polycarboxylate - type water - reducing agent, and the activator is a mixture of sodium silicate and calcium hydroxide in a mass ratio of 3:

1.

8. A preparation method of a soil solidification composite agent containing bioenzymes according to any one of claims 1 to 7, characterized in that, It includes the following steps: Step S1. The inorganic nano - composite and the composite bio - enzyme are impregnated at - 0.08 to - 0.1 MPa for 30 min, and then freeze - dried at - 30 °C for 10 hours to obtain the first mixture; Step S2. Add steel slag powder, slag and desulfurized gypsum in proportion to a dry powder mixer and stir evenly to obtain the second mixture; Step S3. Mix the organic enhancer and water in a mass ratio of 1:(1 - 2), and stir in a 60 °C water bath until completely dissolved to obtain a mixed solution; Step S4. Mix the first mixture, the second mixture, the mixed solution, the penetrant, the pH buffer, the water - reducing agent and the activator evenly, and finally granulate and dry at 50 °C until the moisture content is less than 1% to obtain the soil - solidifying composite agent containing bio - enzyme.

9. Use of a soil solidification composite agent containing bioenzymes according to any one of claims 1 to 7, characterized in that, It is used for soil solidification. The specific operation is as follows: Mix the soil - solidifying composite agent containing bio - enzyme evenly with soft soil with a moisture content greater than 40%, stand for 2 - 3 h, then supplement 0.5 - 1% CaCl2 solution, and finally cover with an oxygen - permeable membrane for curing for 6 - 8 h.

10. Use of a soil solidification composite agent containing biological enzymes according to claim 9, characterized in that, The addition amount of the soil - solidifying composite agent containing bio - enzyme is 5 - 15% of the mass of the soft soil, the addition amount of the CaCl2 solution is 0.5 - 1% of the mass of the soft soil, and the concentration of CaCl2 is 3 mol / L.