A soil solidifying composite agent containing a biological enzyme and a preparation method and application thereof

Abstract

The application belongs to the technical field of soil solidification and specifically relates to a soil solidification composite agent containing biological enzymes and a preparation method and application thereof. The soil solidification composite agent contains composite biological enzymes, inorganic nano-composites, inorganic gel materials, organic reinforcing materials, penetrating agents, pH buffering agents, water reducing agents and activators. The preparation method comprises the following steps: first, vacuum treatment is performed on the inorganic nano-composites and the composite biological enzymes, and then steel slag powder, slag and desulfurization gypsum are uniformly stirred; second, the organic reinforcing materials are mixed with water, heated and stirred in a water bath to be uniformly mixed; and finally, the three kinds of materials and other additives are mixed and granulated to obtain the soil solidification composite agent containing biological enzymes. The composite biological enzymes of the application can destroy the double electric layer structure of soil, reduce the hydrophilicity and form a waterproof layer. The nano-inorganic composite can load enzyme molecules, and the enzyme loading rate can be improved by combining with the negative pressure immersion process to achieve the effect of slow release. The inorganic gel materials and the organic reinforcing materials can synergistically reduce the porosity and improve the compressive strength.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of soil solidification, and particularly relates to a soil solidification composite agent containing a biological enzyme and a preparation method and application thereof. BACKGROUND

[0002] In the practice of road engineering, the traditional roadbed improvement materials have significant technical bottlenecks. For example, the lignin contains functional groups such as benzene propanol units, hydroxyl groups and methoxyl groups in the molecular structure, which presents a complex three-dimensional network structure, resulting in problems such as uneven molecular weight distribution and poor accessibility of reaction sites. In actual engineering, incomplete solidification reaction and large dispersion of modification effect often occur. For soil with high water content, although lime can reduce the liquid limit through ion exchange, the release rate of calcium ions is slow, and it needs to be added in excess to meet the compaction degree requirement, which is poor in economy and easy to cause stirring segregation. Although lime has the characteristics of rapid water absorption, the intense hydration heat release reaction will cause the construction window period to be shortened, and it is difficult to accurately control the reaction progress under complex working conditions. Although fly ash materials have the effect of micro-aggregate, their volcanic ash activity index is generally low, which is difficult to meet the strength requirement of heavy traffic pavement, and the application of these traditional raw materials also has the problem of increased economic cost. Under this background, the biological enzyme soil solidification technology has attracted widespread attention in the academic field due to its environmental friendly characteristics. This new type of solidification agent is mainly derived from plant cell extracts, and the active ingredients such as protease and lipase prepared by biological fermentation process can catalyze the directional transformation of soil organic matter at room temperature. Its action mechanism is as follows: the soil solidification agent made of 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. The substance is adsorbed and replaced by clay ions, thereby weakening the water absorption capacity of soil particles and reducing their hydrophilicity, shielding water, forming a waterproof soil layer, and through compaction, the soil loses the ability to reabsorb water after compaction, and even after compaction, adding water will not affect the mechanical benefits of the soil after compaction. The reaction is micron-level, and the presence of wet substances and small particles of clay size is essential. By increasing the density of the soil, the strength and stability of the soil can be improved, which can effectively reduce the swelling of the soil and effectively improve the liquefaction phenomenon caused by the dynamic load of the vehicle on the silty roadbed, and prolong the service life of the road.

[0003] Since the 1980s, researchers in developed countries have been working hard on the research of soil solidification technology using biological enzymes. They have developed various soil solidification agent materials such as Conaidsuper, Terrazyme, Permazyme, Roadbond enzyme, etc. The Terrazyme series products developed by Enzyme Solutions Company in the United States have completed engineering verification in more than 50 countries, and the data shows that it can increase the roadbed elastic modulus by more than 300%. Compared with the long research and application history in developed countries such as Europe and the United States, China started late and the time is short, and the research of new soil solidification agent needs to be strengthened. Although the enzyme soil solidification technology has many advantages, it still faces some challenges in practical application. The most important one is the problem of enzyme activity maintenance. Enzymes have high requirements for external environment such as pH when they exert catalytic activity. Direct mixing with soil may cause enzyme deactivation and thus poor solidification effect.

[0004] The technical solution of the patent with publication number CN118755481A discloses a soil solidification material based on original enzyme modified nanoparticles and solid waste. The soil solidification material includes the following components by weight: industrial solid waste 8-12 parts, activator 2-6 parts, original enzyme 0-7 parts, and nanomaterial 0-2 parts. The original enzyme and nanoparticles can not only play their own solidification role, but also modify the nanoparticles to improve their dispersibility and filling effect. The Chinese patent with publication number CN113666705B discloses a soil solidification material based on solid waste and biological enzymes and a preparation method. The technical solution uses a soil solidification material based on solid waste and biological enzymes, which includes recycled aggregate, steel slag, industrial waste gypsum, high-calcium fly ash, inorganic adsorbent, organic adsorbent, and biological enzyme. Through microwave radiation, ultrasonic oscillation, calcination, and other treatment methods, a high-efficiency powdered solidification material is formed, which significantly improves the solidification strength and compactness of the soil. In the above two technical solutions, biological enzymes are only mechanically mixed with nanoparticles, which cannot solve the problem of enzyme deactivation in soil.

[0005] In view of the problem of enzyme deactivation in the existing soil solidification agent containing biological enzymes, which can easily lead to shortening of road life, a soil solidification composite agent containing biological enzymes, its preparation method and application are proposed to improve the drawbacks in the prior art. SUMMARY

[0006] In view of the problem of enzyme deactivation in the existing soil solidification agent containing biological enzymes, which can easily lead to shortening of road life, a soil solidification composite agent containing biological enzymes, its preparation method and application are proposed to improve the drawbacks in the prior art.

[0007] In one aspect, the application provides a soil solidification composite agent containing biological enzymes, comprising the following components by weight: 0.5-3 parts of composite biological enzymes, 10-20 parts of inorganic nano-composites, 30-50 parts of inorganic gel, 10-25 parts of organic reinforcing agents, 3-5 parts of penetrating agents, 0.5-3 parts of pH buffers, 3-5 parts of water-reducing agents, and 10-20 parts of activators.

[0008] The composite biological enzymes are ternary composite enzymes of protease, lipase and cellulase; the inorganic nano-composites are nano-composites with tubular structure and layered structure.

[0009] Preferably, the mass ratio of the 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.

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

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

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

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

[0015] In a second aspect, the application provides a preparation method of a soil solidification composite agent containing biological enzymes, comprising the following steps:

[0016] Step S1. Impregnate the inorganic nano-composites and the composite biological enzymes at -0.08 to -0.1 MPa for 30 min, and then freeze-dry at -30°C for 10 hours to obtain a first mixture;

[0017] Step S2. Add steel slag powder, slag and desulfurization gypsum into a dry powder mixer in a proportion, and stir to obtain a second mixture;

[0018] Step S3. Mix the organic reinforcing agent with water in a mass ratio of 1: (1-2), and stir in a water bath at 60°C until completely dissolved to obtain a mixed solution;

[0019] Step S4. Mix the first mixture, the second mixture, the mixed solution, the penetrating agent, the pH buffer, the water reducing agent and the activator evenly, and finally granulate and dry at 50°C to a water content of less than 1% to obtain the soil solidification composite agent containing the biological enzyme.

[0020] In a third aspect, the application provides an application of the soil solidification composite agent containing the biological enzyme, which is used for soil solidification. The specific operation is as follows: the soil solidification composite agent containing the biological enzyme is uniformly mixed with soft soil with a water content of more than 40%, and is left to stand for 2-3 hours, and then 0.5-1% CaCl2 solution is added. Finally, the soil is covered with an oxygen-permeable film and is cured for 6-8 hours.

[0021] Preferably, the addition amount of the soil solidification composite agent containing the biological enzyme is 5-15% of the mass of the soft soil, and 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 application has the following beneficial effects:

[0023] (1) The protease, lipase and cellulase in the application are compounded in a ratio of 1:(0.3-0.8):(0.5-1.2) to form a synergistic catalytic network. The subtilisin degrades proteinaceous organic matter in the soil, destroys the organic coating layer on the surface of clay particles, exposes the mineral active sites, the Pseudomonas fluorescens lipase decomposes lipid substances, reduces the water adsorption capacity of soil organic matter, and the cellulase decomposes plant fiber residues to release the bound clay particles and promote the physical contact between the particles. The three enzymes synergistically break the double electric layer structure of the soil, reduce the hydrophilicity, and form a waterproof soil layer. The enzyme molecules are embedded in the nanopores under the condition of immersion under negative pressure, which improves the loading rate of the enzyme molecules while maintaining the activity of the enzyme. Based on the slow-release performance of the nanomaterials, the enzyme is released for a long time, which prolongs the service life of the roadbed. The tubular silicon dioxide provides a high specific surface area, adsorbs enzyme molecules through capillary action, and prevents enzyme deactivation. The layered montmorillonite fixes the enzyme molecules through ion exchange, and the interlayer swelling property allows the enzyme active center to be exposed, which improves the catalytic efficiency.

[0024] (2) The interpenetrating network of the inorganic gel and the organic reinforcing material is constructed. The ternary cementitious system of steel slag-slag-desulfurization gypsum releases Ca 2+ and SiO4 2- , and generates C-S-H gel nuclei through initial hydration. The slag releases Al 3+ under the sulfate activation of desulfurization gypsum, and forms ettringite with Ca 2+ to fill the pores. Sodium alginate forms a structural gel with Ca 2+ from the subsequent CaCl2 solution, further fills the voids to improve toughness, and lignosulfonate is degraded into humic acid, which is adsorbed to clay particles through π-π bonds and releases negative charge groups to enhance particle repulsion. The two synergistically reduce the porosity and improve the strength.

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

[0026] (4) The present application controls the time sequence of the enzymatic reaction and ionic crosslinking in the application process. The enzyme is allowed to fully degrade organic matter for 2-3 hours, at which time the water content of the soil decreases. After supplementing the CaCl2 solution, the sodium alginate reacts with Ca 2+ to form a gel network, and the compressive strength is improved. Covering the oxygen-permeable film balances the oxygen demand of the enzyme and the humidity required for the cementation reaction, avoiding enzyme inactivation.

[0027] In summary, the soil solidification composite agent containing biological enzymes provided by the present application realizes the improvement of soil solidification efficiency and long-term stability through multi-level synergy. DETAILED DESCRIPTION

[0028] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific embodiments, structures, features and effects according to the present application are described in detail as follows in combination with the drawings and preferred preparation examples.

[0029] Preparation Example 1

[0030] The present preparation example provides a preparation method of a soil solidification composite agent containing biological enzymes, which is specifically as follows:

[0031] The proportioning of the soil solidification composite agent containing biological enzymes is specifically as follows:

[0032] 1 part of the composite biological enzyme: the mass ratio of the protease, the lipase and the cellulase is 1:0.5:0.9;

[0033] 15 parts of the inorganic nano-composite: the mass ratio of the tubular silica and the layered montmorillonite is 6:4;

[0034] 45 parts of the inorganic gel: the mass ratio of the steel slag powder, the slag and the desulfurization gypsum is 30:54:16;

[0035] 15 parts of the organic reinforcing material: the mass ratio of the sodium alginate and the sodium lignosulfonate is 7:3;

[0036] 4 parts of the penetrating agent: fatty alcohol polyoxyethylene ether;

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

[0038] 4 parts of water-reducing agent: polycarboxylic acid;

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

[0040] The preparation steps are as follows:

[0041] Step S1: Mix the composite biological enzyme with the inorganic nanocomposite and place it 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 a first mixture;

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

[0043] Step S3: Mix sodium alginate and sodium lignosulfonate and add deionized water (the mass ratio of the sum of the mass of sodium alginate and sodium lignosulfonate to the mass of deionized water is 1:1). Stir in a 60°C water bath at 500 rpm 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 the activator to a mixer and stir at 500 rpm for 30 minutes. Finally, shape by an extrusion granulator (pore size 2 mm) and dry with hot air at 50°C until the water content is 0.2% to obtain a soil solidification composite agent containing biological enzymes with a particle size of 1-3 mm.

[0045] Preparation Example 2

[0046] The present preparation example provides a preparation method of a soil solidification composite agent containing biological enzymes, which is as follows:

[0047] The proportioning of the soil solidification composite agent containing biological enzymes is as follows:

[0048] 1.5 parts of composite biological enzyme: the mass ratio of subtilisin, Pseudomonas fluorescens lipase, and cellulase is 1:0.3:0.8;

[0049] 14 parts of inorganic nanocomposite: the mass ratio of tubular silica and layered montmorillonite is 6:4;

[0050] 33 parts of inorganic gel: the mass ratio of steel slag powder, slag, and desulfurization gypsum is 30:54:16;

[0051] 22 parts of organic reinforcing material: the mass ratio of sodium alginate and sodium lignosulfonate is 7:3;

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

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

[0054] 4 parts of water-reducing agent polycarboxylic acid;

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

[0056] The preparation steps are as follows:

[0057] Step S1: Mix the composite biological enzyme with the inorganic nanocomposite and place it 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 a first mixture;

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

[0059] Step S3: Mix sodium alginate and sodium lignosulfonate and add deionized water (the mass ratio of the sum of the mass of sodium alginate and sodium lignosulfonate to the mass of deionized water is 1:1.2). 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 the activator to a mixer and stir at 500 rpm for 30 minutes. Finally, shape by an extrusion granulator (pore size 2 mm) and dry with hot air at 50°C until the water content is 0.2% to obtain a soil solidification composite containing biological enzymes with a particle size of 1-3 mm.

[0061] Preparation Example 3

[0062] The present preparation example provides a preparation method of a soil solidification composite containing biological enzymes, which is as follows:

[0063] The ratio of the soil solidification composite containing biological enzymes is as follows:

[0064] 2 parts of composite biological enzyme: the mass ratio of subtilisin, Pseudomonas fluorescens lipase, and cellulase is 1:0.8:1.2;

[0065] 10 parts of inorganic nanocomposite: tubular silica and layered montmorillonite mixed in a mass ratio of 6:4;

[0066] 40 parts of inorganic gel: steel slag powder, slag, and desulfurization gypsum mixed in a mass ratio of 30:54:16;

[0067] 18 parts of organic reinforcing agent: sodium alginate and sodium lignosulfonate mixed in a mass ratio of 7:3;

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

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

[0070] 4 parts of water-reducing agent polycarboxylic acid;

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

[0072] The preparation method is as follows:

[0073] Step S1: The composite enzyme and inorganic nanocomposite are mixed and placed in a vacuum impregnation tank, the vacuum degree is adjusted to-0.04 MPa, and impregnation is carried out for 30 minutes. It is transferred to a freeze dryer and dried at-30℃ for 10 hours to obtain a first mixture;

[0074] Step S2: Steel slag powder, slag, and desulfurization gypsum are added to a dry powder mixer and stirred at a speed of 200 rpm for 20 minutes to obtain a second mixture;

[0075] Step S3: Sodium alginate and sodium lignosulfonate are mixed and added with deionized water (the mass ratio of the sum of the mass of sodium alginate and sodium lignosulfonate to the mass of deionized water is 1:1.5), and stirred at 500 rpm in a 60℃ water bath until completely dissolved to obtain a mixed solution;

[0076] Step S4: The first mixture, the second mixture, the mixed solution, the fatty alcohol polyoxyethylene ether, the sodium dihydrogen phosphate, the polycarboxylic acid, and the activator are added to a mixer and stirred at 500 rpm for 30 minutes. Finally, it is formed by an extrusion granulator (pore size 2 mm) and dried by hot air at 50℃ to a water content of 0.2% to obtain a soil solidification composite agent containing a biological enzyme with a particle size of 1-3 mm.

[0077] Preparation Example 4

[0078] The present preparation example provides a preparation method of a soil solidification composite agent containing a biological enzyme, which is as follows:

[0079] The proportion of the soil solidification composite agent containing a biological enzyme is as follows:

[0080] 0.5 parts of composite biological enzyme: wherein the mass ratio of subtilisin, Pseudomonas fluorescens lipase, and cellulase is 1:0.4:0.5 mixed;

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

[0082] 30 parts of inorganic gel material: steel slag powder, slag and desulfurization gypsum are mixed in a mass ratio of 30:54:16;

[0083] 25 parts of organic reinforcing material: sodium alginate and sodium lignosulfonate are mixed in a mass ratio of 7:3;

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

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

[0086] 5 parts of water reducing agent polycarboxylic acid;

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

[0088] The preparation method is as follows:

[0089] Step S1: The composite enzyme and inorganic nanocomposite are mixed and placed in a vacuum impregnation tank, the vacuum degree is adjusted to-0.02 MPa, and impregnation is carried out for 30 minutes. Transfer to a freeze dryer, dry at-30℃ for 10 hours to obtain a first mixture;

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

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

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

[0093] Preparation Example 5

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

[0095] The proportion of the soil solidification composite agent containing a biological enzyme is specifically as follows:

[0096] 3 parts of composite biological enzyme: wherein, the mass ratio of subtilisin, fluorescent pseudomonas lipase and cellulase is 1:0.7:1;

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

[0098] 50 parts of inorganic gel: steel slag powder, slag and desulfurization gypsum mixed in a mass ratio of 30:54:16;

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

[0100] 5 parts of penetrating agent: 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: sodium silicate and calcium hydroxide mixed in a mass ratio of 3:1.

[0104] The preparation method is as follows:

[0105] Step S1: The composite enzyme is mixed with the inorganic nano-composite and placed in a vacuum impregnation tank. The vacuum degree is adjusted to-0.1 MPa, and impregnation is carried out for 30 minutes. Then it is transferred to a freeze dryer and dried at-30℃ for 10 hours to obtain a first mixture;

[0106] Step S2: Steel slag powder, slag and desulfurization gypsum are added to a dry powder mixer and stirred at a speed of 200 rpm for 20 minutes to obtain a second mixture;

[0107] Step S3: Sodium alginate and sodium lignosulfonate are mixed and deionized water is added (the mass ratio of the sum of the mass of sodium alginate and sodium lignosulfonate to the mass of deionized water is 1:2). Stirring is carried out in a 60℃ water bath at a speed of 500 rpm until complete dissolution to obtain a mixed solution;

[0108] Step S4: The first mixture, the second mixture, the mixed solution, the fatty alcohol polyoxyethylene ether, the sodium dihydrogen phosphate, the polycarboxylic acid and the activator are added to a mixer and stirred at a speed of 500 rpm for 30 minutes. Finally, it is formed by an extrusion granulator (pore size 2 mm) and dried by hot air at 50℃ until the water content is 0.2% to obtain a soil solidification composite agent containing a biological 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 no protease is added.

[0111] Comparative Preparation Example 2

[0112] The difference between this comparative preparation example and Preparation Example 1 is that no lipase is added.

[0113] Comparative Preparation Example 3

[0114] The difference between this comparative preparation example and Preparation Example 1 is that no cellulase is added.

[0115] Comparative Preparation Example 4

[0116] The difference between this comparative preparation example and Preparation Example 1 is that no cellulase is added.

[0117] Comparative Preparation Example 5

[0118] The difference between this comparative preparation example and Preparation Example 1 is that no cellulase is added.

[0119] Comparative Preparation Example 6

[0120] The difference between this comparative preparation example and Preparation Example 1 is that no cellulase is added.

[0121] Comparative Preparation Example 7

[0122] The difference between this comparative preparation example and Preparation Example 1 is that no cellulase is added.

[0123] Comparative Preparation Example 8

[0124] The difference between this comparative preparation example and Preparation Example 1 is that no cellulase is added.

[0125] Comparative Preparation Example 9

[0126] The difference between this comparative preparation example and Preparation Example 1 is that no cellulase is added.

[0127] Comparative Preparation Example 10

[0128] The difference between this comparative preparation example and Preparation Example 1 is that no cellulase is added.

[0129] Example 1

[0130] The soil stabilizing composite agent containing a biological enzyme prepared in Preparation Example 1 is selected in this example. The soft soil with a moisture content of 45% is mixed with the composite agent at a ratio of 5% by mass of the soft soil. The mixture is mixed for 20 minutes using a rotary cultivator (rotational speed 120 rpm). After spreading, the mixture is left to stand for 2 hours (ambient temperature 25°C). A 0.5% CaCl2 solution (concentration 3 mol / L) is sprayed thereon. The compactness is 96%. An oxygen permeable film is applied. The mixture is cured for 7 hours. The 7-day compressive strength is 9.62 MPa and the 28-day compressive strength is 11.74 MPa. The strength loss rate after 50 freeze-thaw cycles is 4.73%.

[0131] Example 2

[0132] The embodiment selects the soil solidifying composite agent containing biological enzyme prepared in Preparation Example 2, and the soft soil with a water content of 45% is mixed, 8% of the composite agent is added according to the mass of the soft soil, and the rotary tiller (rotating speed 120 rpm) is used for mixing for 20 minutes. After paving, it is left for 2 hours (environmental temperature 25 DEG C). 0.6% CaCl2 solution (concentration 3 mol / L) is sprayed, the compaction degree reaches 96%, the oxygen permeable film is covered, and curing is performed for 7 hours. The 7-day compressive strength is 8.94 MPa, the 28-day compressive strength is 10.79 MPa, and the strength loss rate after 50 freeze-thaw cycles is 5.88%.

[0133] Example 3

[0134] The embodiment selects the soil solidifying composite agent containing biological enzyme prepared in Preparation Example 3, and the soft soil with a water content of 45% is mixed, 10% of the composite agent is added according to the mass of the soft soil, and the rotary tiller (rotating speed 120 rpm) is used for mixing for 20 minutes. After paving, it is left for 2.5 hours (environmental temperature 25 DEG C). 0.8% CaCl2 solution (concentration 3 mol / L) is sprayed, the compaction degree reaches 96%, the oxygen permeable film is covered, and curing is performed for 7 hours. The 7-day compressive strength is 9.02 MPa, the 28-day compressive strength is 11.17 MPa, and the strength loss rate after 50 freeze-thaw cycles is 5.07%.

[0135] Example 4

[0136] The embodiment selects the soil solidifying composite agent containing biological enzyme prepared in Preparation Example 4, and the soft soil with a water content of 45% is mixed, 12% of the composite agent is added according to the mass of the soft soil, and the rotary tiller (rotating speed 120 rpm) is used for mixing for 20 minutes. After paving, it is left for 2.5 hours (environmental temperature 25 DEG C). 0.9% CaCl2 solution (concentration 3 mol / L) is sprayed, the compaction degree reaches 96%, the oxygen permeable film is covered, and curing is performed for 7 hours. The 7-day compressive strength is 8.75 MPa, the 28-day compressive strength is 9.94 MPa, and the strength loss rate after 50 freeze-thaw cycles is 6.03%.

[0137] Example 5

[0138] The embodiment selects the soil solidifying composite agent containing biological enzyme prepared in Preparation Example 5, and the soft soil with a water content of 45% is mixed, 15% of the composite agent is added according to the mass of the soft soil, and the rotary tiller (rotating speed 120 rpm) is used for mixing for 20 minutes. After paving, it is left for 3 hours (environmental temperature 25 DEG C). 1% CaCl2 solution (concentration 3 mol / L) is sprayed, the compaction degree reaches 96%, the oxygen permeable film is covered, and curing is performed for 7 hours. The 7-day compressive strength is 9.17 MPa, the 28-day compressive strength is 10.97 MPa, and the strength loss rate after 50 freeze-thaw cycles is 5.95%.

[0139] Comparative Example 1

[0140] The difference between the present comparative example and Example 1 is that the soil solidifying composite agent containing a bioenzyme prepared in Preparation Example 1 is used. The 7-day compressive strength is 8.15 MPa, the 28-day compressive strength is 9.04 MPa, and the strength loss rate after 50 freeze-thaw cycles is 7.85%.

[0141] Comparative Example 2

[0142] The difference between the present comparative example and Example 1 is that the soil solidifying composite agent containing a bioenzyme prepared in Preparation Example 2 is used. The 7-day compressive strength is 7.98 MPa, the 28-day compressive strength is 8.86 MPa, and the strength loss rate after 50 freeze-thaw cycles is 7.74%.

[0143] Comparative Example 3

[0144] The difference between the present comparative example and Example 1 is that the soil solidifying composite agent containing a bioenzyme prepared in Preparation Example 3 is used. The 7-day compressive strength is 8.01 MPa, the 28-day compressive strength is 9.12 MPa, and the strength loss rate after 50 freeze-thaw cycles is 7.20%.

[0145] Comparative Example 4

[0146] The difference between the present comparative example and Example 1 is that the soil solidifying composite agent containing a bioenzyme prepared in Preparation Example 4 is used. The 7-day compressive strength is 7.24 MPa, the 28-day compressive strength is 7.96 MPa, and the strength loss rate after 50 freeze-thaw cycles is 8.11%.

[0147] Comparative Example 5

[0148] The difference between the present comparative example and Example 1 is that the soil solidifying composite agent containing a bioenzyme prepared in Preparation Example 5 is used. The 7-day compressive strength is 7.35 MPa, the 28-day compressive strength is 8.01 MPa, and the strength loss rate after 50 freeze-thaw cycles is 8.56%.

[0149] Comparative Example 6

[0150] The difference between the present comparative example and Example 1 is that the soil solidifying composite agent containing a bioenzyme prepared in Preparation Example 6 is used. The 7-day compressive strength is 6.99 MPa, the 28-day compressive strength is 7.81 MPa, and the strength loss rate after 50 freeze-thaw cycles is 8.45%.

[0151] Comparative Example 7

[0152] The difference between the present comparative example and Example 1 is that the soil solidifying composite agent containing a bioenzyme prepared in Preparation Example 7 is used. The 7-day compressive strength is 7.49 MPa, the 28-day compressive strength is 7.79 MPa, and the strength loss rate after 50 freeze-thaw cycles is 8.68%.

[0153] Comparative Example 8

[0154] The comparative example is different from example 1 in that the soil solidifying composite agent containing biological enzyme prepared in preparation example 8 is selected. The 7-day compressive strength is 7.41 MPa, the 28-day compressive strength is 8.94 MPa, and the strength loss rate after 50 freeze-thaw cycles is 7.49%.

[0155] Comparative example 9

[0156] The comparative example is different from example 1 in that the soil solidifying composite agent containing biological enzyme prepared in preparation example 9 is selected. The 7-day compressive strength is 7.57 MPa, the 28-day compressive strength is 7.96 MPa, and the strength loss rate after 50 freeze-thaw cycles is 8.11%.

[0157] Comparative example 10

[0158] The comparative example is different from example 1 in that the soil solidifying composite agent containing biological enzyme prepared in preparation example 10 is selected. The 7-day compressive strength is 7.09 MPa, the 28-day compressive strength is 7.81 MPa, and the strength loss rate after 50 freeze-thaw cycles is 8.37%.

[0159] By comparing examples 1-5 and comparative examples 1-10, it can be seen that the preparation method of the application can realize efficient and stable soil solidification through multi-level synergistic mechanism. The composite biological enzyme destroys the double electric layer structure of the soil, reduces the hydrophilicity to form a waterproof layer; the nano inorganic compound loads the enzyme molecules, and the enzyme loading rate is improved by combining the negative pressure immersion process to achieve the effect of slow release. The inorganic gel and the organic reinforcing material paste synergistically reduce the porosity and improve the compressive strength.

[0160] The above is only a preferred preparation example of the application, and does not limit the application in any form. Although the application has been disclosed as above, it is not intended to limit the application. Any person skilled in the art can make some changes or modifications to the equivalent preparation examples without departing from the scope of the technical solution of the application. Any modification, equivalent change and modification of the above preparation examples, which do not depart from the technical solution of the application, are still within the scope of the technical solution of the application.

Claims

1. A soil stabilizing composite agent containing bio-enzymes, characterized in that, It includes the following components in parts by weight: 0.5-3 parts of compound bio-enzyme, 10-20 parts of inorganic nanocomposite; 30-50 parts of inorganic gel, 10-25 parts of organic reinforcing agent, 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 bioenzyme is a ternary composite enzyme consisting of protease, lipase, and cellulase; the inorganic nanocomposite is a nanocomposite with tubular and layered structures. The mass ratio of the protease, lipase, and cellulase is 1:(0.3-0.8):(0.5-1.2). The protease is Bacillus subtilis protease, and the lipase is Pseudomonas fluorescens lipase. The inorganic nanomaterial with a tubular structure is silicon dioxide, and the inorganic nanomaterial with a layered structure is montmorillonite. The mass ratio of silicon dioxide to montmorillonite is 6:

4. The inorganic gel is a mixture of steel slag powder, slag, and desulfurized gypsum in a mass ratio of 30:54:16; The organic reinforcing material is a mixture of sodium alginate and sodium lignin sulfonate in a mass ratio of 7:

3.

2. The soil stabilizing composite containing bio-enzymes 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 a polycarboxylic acid water-reducing agent, and the activator is a mixture of sodium silicate and calcium hydroxide in a mass ratio of 3:

1.

3. A method for preparing a soil stabilization composite containing biological enzymes as described in any one of claims 1 to 2, characterized in that, Includes the following steps: Step S1. The inorganic nanocomposite and the composite bioenzyme were impregnated at -0.08~-0.1MPa for 30 min, followed by freeze drying at -30℃ for 10 h to obtain the first mixture; Step S2. Add the inorganic gel to a dry powder mixer and stir until homogeneous to obtain a second mixture; Step S3. Mix the organic enhancer with water at a mass ratio of 1:(1~2), and stir in a water bath at 60°C until completely dissolved to obtain a mixture; Step S4. Mix the first mixture, the second mixture, the mixed liquid, 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 a soil solidification composite containing biological enzymes.

4. The application of the soil stabilization composite containing bio-enzymes as described in any one of claims 1 to 2, characterized in that, For soil stabilization, the specific operation is as follows: mix the soil stabilization compound containing biological enzymes with soft soil with a moisture content greater than 40%, let it stand for 2-3 hours, then add 0.5-1% CaCl2 solution, and finally cover with an oxygen-permeable membrane for 6-8 hours of curing.

5. The application of the soil stabilization composite containing bio-enzymes according to claim 4, characterized in that, The amount of the soil stabilizing compound containing bio-enzymes added is 5-15% of the mass of the soft soil, the amount of CaCl2 solution added is 0.5-1% of the mass of the soft soil, and the concentration of CaCl2 is 3 mol / L.