An interface enhanced peat soil solidification method

Abstract

The present application relates to peat recycling technical field, especially to a kind of interface enhanced peat solidification method, comprising: hydrophobic modified mesoporous silica nanoparticles and sodium persulfate are dispersed in water, and pre-dispersion is obtained, then and peat are mixed;Silane coupling agent aqueous solution is added to the above peat, and mixing is obtained to obtain modified peat slurry;Nano montmorillonite, nano silicon dioxide and cement clinker micro powder are dry mixed, and activated premix is obtained;The activated premix, Portland cement, microbial bacteria liquid, urea and calcium chloride are mixed with the modified peat slurry, shaping and curing conservation;Through chemical bonding and physical filling means, the strengthening system from molecular to microscale is jointly constructed, and the overall mechanical properties and durability of peat are improved.

Description

Technical Field

[0001] This invention relates to the field of peat reuse technology, and more particularly to an interface-enhanced peat solidification method. Background Technology

[0002] Peat soil, as a special soft soil rich in organic matter, has high compressibility and low strength. Its engineering properties are extremely poor. When used directly as a roadbed or foundation, it has prominent problems such as low bearing capacity, large deformation and insufficient stability. It usually needs to be solidified before it can be used.

[0003] Currently, cement-based curing agents are the most commonly used materials for improving this type of soft soil. However, traditional cement curing technology has drawbacks such as low curing efficiency, slow strength growth, and poor long-term stability when treating peat soil. This is mainly due to the high organic matter content in peat soil. On the one hand, organic matter coats soil particles to form a hydrophobic surface, which seriously hinders the effective contact and bonding between cement hydration products and soil particles. On the other hand, the acidity of organic matter and its interference with the cement hydration process lead to the formation of a loose, porous, and weak interface transition zone between soil particles and cement stone. This area becomes a stress concentration point and seepage channel in the solidified soil, significantly weakening the overall mechanical properties and durability.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the general background of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] This invention provides an interface-enhanced peat solidification method, which constructs a reinforcement system from the molecular to the microscale through chemical bonding and physical filling, thereby improving the overall mechanical properties and durability of peat and effectively solving the problems in the prior art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for solidifying peat soil with enhanced interface, comprising: S1 disperses hydrophobically modified mesoporous silica nanoparticles and sodium persulfate in water to obtain a pre-dispersion, which is then mixed with peat moss. More specifically, the organic components in peat moss are highly hydrophobic. By hydrophobically modifying the mesoporous silica, its surface properties become similar to those of the organic matter. Based on the principle of like dissolves like, the hydrophobically modified mesoporous silica nanoparticles can actively and preferentially adsorb onto the surface of the organic matter. S2. Add an aqueous solution of silane coupling agent to the peat soil in step S1 and mix to obtain a modified peat soil slurry. More specifically, by adding the pre-dispersion liquid and the aqueous solution of silane coupling agent to the peat soil in sequence, the ineffective reaction that would occur if the oxidant and the coupling agent came into contact too early in the solution is avoided. After the oxidant target completes the oxidation reaction on the surface of the organic matter to generate a large number of active sites, the coupling agent is then introduced to form a chemical bond, thereby improving the efficiency of interface modification and the strength of chemical bridging. S3 dry-mixes nano-montmorillonite, nano-silica, and cement clinker powder to obtain activated premix; S4 mixes activated premix, silicate cement, microbial inoculum, urea, and calcium chloride with modified peat slurry, then shapes and cures it.

[0007] This invention utilizes hydrophobically modified mesoporous silica nanoparticles as a targeted carrier to transport and enrich sodium persulfate, an oxidant, on the surface of peat organic matter. Sodium persulfate selectively oxidizes humic acid, converting it into active small molecules rich in carboxyl and phenolic hydroxyl groups. The carboxyl groups can form ionic or coordinate bonds with positively charged metal ions or edge sites on the surface of peat particles, which is a very strong bonding mode. Furthermore, the carboxyl and phenolic hydroxyl groups can form a dense hydrogen bond network with the abundant -OH groups on the surface of peat particles, generating a strong physical adsorption force. The active group at one end of the silane coupling agent molecule reacts chemically with the active small molecule, while the hydrolyzable siloxane group at the other end forms a strong Si-O-Si covalent bond with the silicate structure in the subsequent cement hydration products under alkaline conditions, thereby strengthening the chemical connection between soil particles and solidifying agent in a more direct and stable covalent bond bridging mode. At the microstructure level, premixed and dispersed nano-montmorillonite, nano-silica, and cement clinker powder provide high-density hydration nuclei in the interface region, promoting the early and localized formation of dense hydration products. Simultaneously, the introduced microbial mineralization generates calcium carbonate precipitates in the pores of the solidified body, achieving nano- to micron-level physical filling of the pores in the interface transition zone, enhancing the physical density and mechanical interlocking ability of the interface. The combined effect of interface enhancement with silane chemical bonding as the core and microstructure filling and compaction significantly improves the interfacial bonding strength and overall mechanical properties of the solidified body.

[0008] Furthermore, the preparation method of hydrophobically modified mesoporous silica nanoparticles includes: Mesoporous silica nanoparticles are reacted with a silane coupling agent in an ethanol solution at 60-80°C, and then washed and dried to obtain the final product; wherein the amount of silane coupling agent is 5-15% of the mass of the mesoporous silica nanoparticles; and wherein the particle size range of the mesoporous silica nanoparticles is 50-200 nm.

[0009] In the above preparation process, under the conditions of ethanol solution and heating at 60~80℃, the silane coupling agent undergoes hydrolysis to generate reactive silanol; subsequently, the silanol and the silanol on the surface of silica undergo a dehydration condensation reaction to form a strong Si-O-Si covalent bond, thereby chemically grafting the silane coupling agent onto the particle surface; finally, the hydrophobic organic group carried at the other end of the silane coupling agent faces outward, causing the particle surface properties to change from hydrophilic to hydrophobic; the above dosage range can ensure the formation of monolayer chemical grafting and achieve stable hydrophobic functionalization while maximizing the maintenance of the particle's high specific surface area and pore structure integrity.

[0010] Furthermore, the silane coupling agent is at least one of KH-550, KH-560 and KH-570.

[0011] More specifically, the aforementioned silane coupling agents are all bifunctional molecules. The hydrolyzable siloxane group at one end can form a strong Si-O-Si covalent bond with cement hydration products, while the active functional group at the other end can react efficiently with the active sites such as carboxyl groups and phenolic hydroxyl groups generated after peat soil oxidation, forming a stable chemical bridge.

[0012] Furthermore, the pre-dispersed liquid-solid content is 8-10%, and the weight of the pre-dispersed liquid is 8-10% of the dry weight of the peat soil. More specifically, the pre-dispersed liquid-solid content of 8-10% enables the carrier to efficiently complete targeted delivery with appropriate concentration and fluidity through the mechanical energy provided by stirring and hydrophobic interactions. The typical organic matter content range in peat soil is 30-70%, which is the range obtained by estimating the number of moles of functional groups that can be oxidized and approximating the effective oxygen equivalent provided by sodium persulfate. This range ensures that there is sufficient oxidant to react with most of the surface organic matter, while avoiding damage to the soil structure due to excessive oxidation. The concentration of the silane coupling agent aqueous solution is 4-6%, and the dosage is 0.5-0.8 times the mass of the pre-dispersion liquid. More specifically, the concentration of 4-6% keeps the coupling agent molecules highly reactive and dispersible, and avoids the intermolecular condensation that occurs too quickly due to excessive concentration, which would affect the effective bonding with the interface. The amount of pre-dispersion directly determines the number of active small molecules. By setting the dosage of the silane coupling agent aqueous solution to 0.5 to 0.8 times the mass of the pre-dispersion, the number of silane coupling agent molecules can match the number of active small molecules. This not only avoids incomplete interfacial bonding caused by insufficient coupling agent, but also prevents molecular self-aggregation or the formation of weak interfacial layers that may be caused by excessive coupling agent.

[0013] Furthermore, the peat soil obtained in step S1 is left to stand at 20~30℃ for 30~60 minutes before proceeding to step S2.

[0014] More specifically, during the aforementioned time period, sodium persulfate can more thoroughly transform hydrophobic organic matter into an adhesive surface rich in active groups, thereby creating more and more uniform bonding sites for the subsequently added silane coupling agent.

[0015] Furthermore, the mass ratio of nano-montmorillonite, nano-silica, and cement clinker powder is 1:1~2:8~18; The particle size of nano-montmorillonite is 30~100nm, the particle size of nano-silica is 10~30nm, and the particle size of cement clinker powder is 1~10μm.

[0016] More specifically, the hydration of cement clinker powder forms the main cementitious skeleton and initially fills the larger pores; nano-montmorillonite, with its layered structure, inserts into and adsorbs into the small and medium pores between the skeleton, providing physical support and barrier; and the more active nano-silica further penetrates into even smaller pores, generating secondary gels through volcanic ash reaction to achieve ultimate densification. The three components construct a continuous dense structure from micrometers to nanometers, significantly reducing the porosity and average pore size of the interface region.

[0017] Furthermore, the concentration of Bacillus pasteurellii in the microbial culture was 1×10⁻⁶. 8 ~5×10 8 CFU / mL.

[0018] More specifically, the urease secreted by Bacillus pasteurellii can efficiently catalyze the hydrolysis of urea, rapidly generating carbonate ions and alkalinity in the local microenvironment. The carbonate ions then combine with calcium ions in the system, depositing calcium carbonate crystals in situ. This process acts on the micropores and interfacial transition zones that were not fully filled by cement hydration. The generated calcium carbonate, as a natural cementing and filling material, densifies the pore structure from the nanometer to the micrometer scale, significantly improving the mechanical interlocking ability of the interface and the overall density of the solidified body. The above concentration ensures that there is a sufficiently high number of highly active bacteria per unit volume, which can quickly start and maintain an effective mineralization reaction rate, avoiding reaction lag or insufficient precipitation due to insufficient bacterial count.

[0019] Furthermore, the amounts of each component relative to the dry peat soil mass are as follows: silicate cement 30-50%, microbial inoculum 1.5-5.0%, urea and calcium chloride 0.6-2.5%, and activated premix 4.5-12.5%.

[0020] More specifically, 30-50% silicate cement is the main cementing material, providing a basic strength framework and the necessary alkaline environment; 4.5-12.5% ​​activated premix serves as a nano-functional phase, strengthening the interfacial transition zone; 1.5-5.0% bacterial solution and 0.6-2.5% urea and calcium chloride constitute optimized biomineralization units, generating supplementary cement in the pores.

[0021] Furthermore, urea and calcium chloride are added in the form of an aqueous solution with a concentration of 20-40%, with a molar ratio of 1:1-1.2; More specifically, urea and calcium chloride are added in the form of a 20-40% aqueous solution, which allows them to be rapidly dispersed in the entire system in molecular / ionic form, avoiding uneven mixing and local concentration runaway that may be caused by direct addition of solids; the molar ratio of 1:1 to 1.2 allows the carbonate ions produced by urea hydrolysis to achieve almost complete precipitation transformation with calcium ions, and the slightly excess calcium ions can effectively compensate for the part that may be complexed by peat organic matter, and drive the reaction to generate calcite-type calcium carbonate with the best cementing performance.

[0022] Furthermore, methods for curing and maintaining the condition include: Q1 is cured in a closed environment at a temperature of 25±1℃ and a relative humidity of ≥95% for 18~24h; this step allows the silicate cement to fully undergo early hydration, form a preliminary strength skeleton, and establish the alkaline environment necessary for the system, which is also conducive to the rapid colonization and preliminary metabolic activities of Bacillus pasteurellii. Q2 Remove the seal and cure in an environment with a temperature of 30±2℃ and a relative humidity of ≥90% for 48~72h. This step increases the temperature, which can significantly stimulate the urease activity of Bacillus pasteurellii, greatly increasing the rate and amount of urea decomposition and calcium carbonate precipitation. This stage also promotes the secondary hydration reaction of cement, which leads to a rapid increase in the strength of the solidified body. Removing the seal allows some excess moisture to evaporate gently, which helps to further compact the structure. Q3 Curing is carried out in a standard curing room at a temperature of 20±2℃ and a relative humidity of ≥95% until the specified age. This step allows the cured body to complete long-term performance development under standard conditions, ensuring the stability of the final mechanical properties and durability.

[0023] The technical solution of this invention can achieve the following technical effects: This invention utilizes the targeted delivery effect of hydrophobically modified mesoporous silica to selectively oxidize the organic matter in peat soil with sodium persulfate, generating active small molecules rich in carboxyl / phenolic hydroxyl groups. These active small molecules are firmly bound to soil particles through a network of ionic bonds, coordination bonds, and hydrogen bonds. On this basis, one end of a silane coupling agent is bonded to the active small molecules, while the other end forms a Si-O-Si covalent bond with cement hydration products in an alkaline environment. This constructs a complete interface enhancement system from strong physical adsorption to stable chemical bridging, fundamentally strengthening the bond between soil and solidifying agent. At the microstructure level, premixed and dispersed nano-montmorillonite, nano-silica, and cement clinker powder provide high-density hydration nuclei in the interface region, promoting the early and localized formation of dense hydration products. Simultaneously, the introduced microbial mineralization generates calcium carbonate precipitates in the pores of the solidified body, achieving nano- to micron-level physical filling of the pores in the interface transition zone, enhancing the physical density and mechanical interlocking ability of the interface. The combined effect of interface enhancement with silane chemical bonding as the core and microstructure filling and compaction significantly improves the interfacial bonding strength and overall mechanical properties of the solidified body. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the process for an interface-enhanced peat solidification method. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] The above description is merely an overview of the technical solution of this application. In order to make the technical means of this application clearer and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below.

[0029] Example 1:

[0030] This embodiment provides a method for solidifying peat soil with enhanced interface, the specific steps of which are as follows: S1 disperses hydrophobically modified mesoporous silica nanoparticles and sodium persulfate in water to obtain a pre-dispersion, which is then mixed with peat moss; Specifically: Take 1000g of dry peat soil for later use, with an organic matter content of approximately 55%; 10g of hydrophobically modified mesoporous silica nanoparticles and 5g of sodium persulfate were weighed and added to 85g of deionized water. The mixture was then ultrasonically dispersed to obtain 100g of pre-dispersion. The hydrophobically modified mesoporous silica nanoparticles were prepared as follows: 10g of mesoporous silica nanoparticles (average particle size 100nm) were reacted with 1.0g of silane coupling agent KH-550 in 60mL of ethanol at 70℃ for 5h. After washing and drying, the mixture was obtained. Add the pre-dispersed liquid and peat to a mixer and mix at 60 rpm for 20 minutes. After mixing, let the mixture stand at 25°C for 45 minutes.

[0031] S2 Add an aqueous solution of silane coupling agent to the peat soil in step S1 and mix to obtain modified peat soil slurry; Specifically, add 50g of a 5% KH-550 aqueous solution to the mixture after it has been allowed to stand, which is 0.5 times the mass of the pre-dispersion solution. Increase the stirring speed to 100 rpm and continue stirring for 25 minutes to obtain modified peat slurry.

[0032] S3 dry-mixes nano-montmorillonite, nano-silica, and cement clinker powder to obtain activated premix; Weigh out 1g of nano-montmorillonite with a particle size of about 50nm, 1.5g of nano-silica with a particle size of about 20nm, and 12g of cement clinker powder with a particle size of about 5μm; place the above three in a ball mill jar and dry mix for 30min to obtain a homogeneous activated premix, totaling 14.5g. S4 mixes activated premix, silicate cement, microbial inoculum, urea and calcium chloride with modified peat slurry, molds and cures it; Specifically, weigh 6.6g of urea and 13.4g of calcium chloride, with a molar ratio of 1:1.1, and dissolve them in 46.7g of deionized water to prepare a urea-calcium chloride mixed aqueous solution with a mass fraction of approximately 30%, totaling approximately 66.7g.

[0033] While stirring, 450g of PO 42.5 silicate cement, 14.5g of activated premix, and a 3×10⁻⁶ concentration of [unspecified ingredient] are added sequentially to the modified peat slurry obtained in step S2. 8 30g of Bacillus pasteurellium culture at CFU / mL and all of the urea-calcium chloride solution prepared above; stir all components at high speed of 120 rpm for 5 minutes until they are evenly mixed.

[0034] Pour the above mixture into a standard mold measuring 40mm×40mm×160mm, vibrate to compact, scrape level, and then cure as follows: Q1: Place the test mold in a closed environment with a temperature of 25℃ and a relative humidity of ≥95% for 21 hours; Q2: Remove the seal and cure in an environment with a temperature of 30℃ and a relative humidity of ≥90% for 60 hours; Q3: Demold the specimens and transfer them to a standard curing room with a temperature of 20℃ and a relative humidity of ≥95% for continued curing until 28 days of age.

[0035] Example 2:

[0036] This embodiment provides a method for solidifying peat soil with enhanced interface, the specific steps of which are as follows: S1 disperses hydrophobically modified mesoporous silica nanoparticles and sodium persulfate in water to obtain a pre-dispersion, which is then mixed with peat moss; Specifically: Take 1000g of dry peat soil for later use, with an organic matter content of approximately 55%; Weigh 8g of hydrophobically modified mesoporous silica nanoparticles and 5g of sodium persulfate, add them to 87g of deionized water, and disperse by ultrasonication to obtain 100g of pre-dispersion; wherein, the preparation method of hydrophobically modified mesoporous silica nanoparticles is as follows: take 10g of mesoporous silica nanoparticles, react with 1.5g of silane coupling agent KH-560 in 60mL of ethanol at 70℃ for 5h, and obtain the product after washing and drying; Add the pre-dispersed liquid and peat to a mixer and mix at 60 rpm for 20 minutes. After mixing, let the mixture stand at 20°C for 60 minutes.

[0037] S2 Add an aqueous solution of silane coupling agent to the peat soil in step S1 and mix to obtain modified peat soil slurry; Specifically, add 64g of a 6% KH-550 aqueous solution to the mixture after it has been allowed to stand, which is 0.8 times the mass of the pre-dispersion solution. Increase the stirring speed to 100 rpm and continue stirring for 25 minutes to obtain modified peat slurry.

[0038] S3 dry-mixes nano-montmorillonite, nano-silica, and cement clinker powder to obtain activated premix; Weigh out 1.5g of nano-montmorillonite with a particle size of about 80nm, 1.5g of nano-silica with a particle size of about 25nm, and 24g of cement clinker powder with a particle size of about 3μm; place the above three materials in a ball mill jar and dry mix for 30min to obtain a homogeneous activated premix, totaling 27g. S4 mixes activated premix, silicate cement, microbial inoculum, urea and calcium chloride with modified peat slurry, molds and cures it; Specifically: Weigh 5g of urea and 9.2g of calcium chloride, with a molar ratio of 1:1.2, and dissolve them in 23.8g of deionized water to prepare a urea-calcium chloride mixed aqueous solution with a mass fraction of approximately 37.5%, totaling approximately 38g.

[0039] While stirring, 500g of PO 42.5 silicate cement, 27g of activated premix, and a 1×10⁻⁶ concentration of [unspecified ingredient] are added sequentially to the modified peat slurry obtained in step S2. 8 50g of Bacillus pasteurellium culture at CFU / mL and all of the urea-calcium chloride solution prepared above; stir all components at 120 rpm for 5 minutes until they are evenly mixed.

[0040] The above mixture was poured into a standard mold of 40mm×40mm×160mm, vibrated to compact, scraped flat, and then cured according to the method in Example 1.

[0041] Example 3:

[0042] This embodiment provides a method for solidifying peat soil with enhanced interface, the specific steps of which are as follows: S1 disperses hydrophobically modified mesoporous silica nanoparticles and sodium persulfate in water to obtain a pre-dispersion, which is then mixed with peat moss; Specifically: Take 1000g of dry peat soil for later use, with an organic matter content of approximately 55%; 9g of hydrophobically modified mesoporous silica nanoparticles and 5g of sodium persulfate were weighed and added to 86g of deionized water. The mixture was then ultrasonically dispersed to obtain 100g of pre-dispersion. The hydrophobically modified mesoporous silica nanoparticles were prepared by taking 10g of mesoporous silica nanoparticles and reacting them with 0.5g of silane coupling agent KH-570 in 60mL of ethanol at 70℃ for 5h. After washing and drying, the mixture was obtained. Add the pre-dispersed liquid and peat to a mixer and mix at 60 rpm for 20 minutes. After mixing, let the mixture stand at 20°C for 60 minutes.

[0043] S2 Add an aqueous solution of silane coupling agent to the peat soil in step S1 and mix to obtain modified peat soil slurry; Specifically, add 60g of a 4% KH-570 aqueous solution to the settled mixture, which is 0.6 times the mass of the pre-dispersion liquid; Increase the stirring speed to 100 rpm and continue stirring for 25 minutes to obtain modified peat slurry.

[0044] S3 dry-mixes nano-montmorillonite, nano-silica, and cement clinker powder to obtain activated premix; Weigh out 0.8g of nano-montmorillonite with a particle size of about 100nm, 1.6g of nano-silica with a particle size of about 15nm, and 8g of cement clinker powder with a particle size of about 8μm; place the above three materials in a ball mill jar and dry mix for 30 minutes to obtain a homogeneous activated premix, totaling 10.4g. S4 mixes activated premix, silicate cement, microbial inoculum, urea and calcium chloride with modified peat slurry, molds and cures it; Specifically: Weigh 3g of urea and 4.6g of calcium chloride, with a molar ratio of 1:1.0, and dissolve them in 15.4g of deionized water to prepare a urea-calcium chloride mixed aqueous solution with a mass fraction of approximately 33%, totaling approximately 23g.

[0045] While stirring, 350g of PO 42.5 silicate cement, 10.4g of activated premix, and a 5×10⁻⁶ concentration of [unspecified ingredient] are added sequentially to the modified peat slurry obtained in step S2. 8 20g of Bacillus pasteurellium culture at CFU / mL and all of the urea-calcium chloride solution prepared above; stir all components at 120 rpm for 5 minutes until they are evenly mixed.

[0046] The above mixture was poured into a standard mold of 40mm×40mm×160mm, vibrated to compact, scraped flat, and then cured according to the method in Example 1.

[0047] Comparative Example 1: Compared with Example 1, this comparative example does not add hydrophobically modified mesoporous silica nanoparticles, but only dissolves sodium persulfate in an equal amount of deionized water and mixes it with peat.

[0048] Comparative Example 2: Compared with Example 1, this comparative example uses unmodified mesoporous silica nanoparticles and sodium persulfate dissolved in an equal amount of deionized water and then mixed with peat moss.

[0049] Comparative Example 3: Compared with Example 1, this comparative example uses an equal mass of cement clinker powder instead of nano-montmorillonite and nano-silica in step S3.

[0050] Comparative Example 4: Compared with Example 1, this comparative example does not add microbial culture, urea and calcium chloride in step S4.

[0051] Comparative Example 5: Compared with Example 1, in this comparative example, the silane coupling agent is directly added to the pre-dispersion liquid of S1 to prepare a mixed slurry containing a carrier, oxidant and coupling agent, and then mixed with peat soil in one go, eliminating the standing step.

[0052] Comparative Example 6: Compared with Example 1, in step S2 of this comparative example, the amount of silane coupling agent aqueous solution was increased to 1.2 times the mass of the pre-dispersion liquid.

[0053] The samples prepared in the examples and comparative examples were subjected to the following tests, and the results are shown in Table 1. The test contents are as follows: (a) Microstructure: The cross-section of the sample was observed using scanning electron microscopy (SEM) in backscattered electron (BSE) mode. Before testing, the solidified sample was cut, ground, and polished to obtain a smooth observation surface. In BSE mode, the difference in atomic number contrast clearly distinguishes peat particles, cement hydration products, and pores. The gradient region with significantly different structures between the edge of the soil particles and the starting point of the continuous cement stone matrix was defined as the interfacial transition zone (ITZ). The density, pore distribution, cracking, and bonding state between the ITZ and the main body on both sides were observed in detail.

[0054] (b) Unconfined compressive strength: The cured samples, after being cured to the specified age, are processed into standard cylindrical specimens. A universal testing machine is used for testing. The specimen is placed vertically at the center of the machine's pressure plate, and an axial load is continuously applied at a constant displacement rate until the specimen fails. The load-displacement curves throughout the loading process are recorded, and the peak load is used to calculate the unconfined compressive strength.

[0055] (c) Strength Retention Rate: Specimens cured to the reference age were used to determine their initial unconfined compressive strength (as a control group). Another group of parallel specimens with the same mix proportions and age were taken and completely immersed in the specified conditions for 7 days. After immersion, the specimens were removed, surface free water was wiped off, and their unconfined compressive strength under saturated water conditions was immediately measured. The strength retention rate was calculated using the following formula: Strength Retention Rate = (Compressive Strength of Immersed Group / Compressive Strength of Control Group) × 100%.

[0056] Table 1 Test results of the examples and comparative examples

[0057] As can be seen from Table 1, the ITZ of the embodiment is extremely thin and dense, without obvious cracks, with soil particles and cement stone tightly bonded together and very few pores. This is due to the present invention, which establishes a strong chemical bond bridge between peat soil and solidifying agent through targeted oxidation and silane coupling, fundamentally solving the problem of weak interfacial adhesion. Nanomaterials fill the interfacial pores, making it more compact, and calcium carbonate generated by microorganisms further fills the micropores, turning the loose and weak areas into a dense and strong band. Therefore, it exhibits higher strength and more stable performance after soaking in water.

[0058] Comparative Example 1, lacking the addition of hydrophobically modified mesoporous silica and sodium persulfate, resulted in untreated peat organic matter, preventing the establishment of effective chemical bonds between soil particles and cement paste. Comparative Example 2, using unmodified mesoporous silica as a carrier, could not adsorb onto the surface of hydrophobic organic matter, leading to inaccurate delivery of oxidants and coupling agents, and inefficient and uneven interfacial modification reactions. Comparative Example 3, lacking nano-montmorillonite and nano-silica, lost the physical means of actively filling pores and providing nuclei to refine hydration products at the microscale. This resulted in insufficient density and numerous micropores in the interfacial transition zone, despite some bonding. Comparative Example 4, without the addition of microbial inoculum, urea, and calcium chloride, lacked the secondary, adaptive filling and cementation of micropores by microbially induced calcium carbonate, resulting in a decrease in strength retention. In Comparative Example 5, the oxidant and coupling agent were pre-mixed in solution, which easily led to side reactions such as redox reactions and mutual depletion. At the same time, the elimination of the standing step saved time for the oxidation reaction to proceed fully, which together led to a serious decrease in the efficiency and quality of interfacial chemical modification. In Comparative Example 6, the dosage of silane coupling agent far exceeded the upper limit of 0.8. Excessive coupling agent could not effectively bond, but instead, molecular self-aggregation occurred at the interface, forming a loose and weakened organic interlayer, which became a new structural defect.

[0059] Although this application has been described in conjunction with specific features and embodiments, it is apparent that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and accompanying drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A method for solidifying peat soil with enhanced interface, characterized in that, include: S1 disperses hydrophobically modified mesoporous silica nanoparticles and sodium persulfate in water to obtain a pre-dispersion, which is then mixed with peat moss; S2 Add an aqueous solution of silane coupling agent to the peat soil in step S1 and mix to obtain modified peat soil slurry; S3 dry-mixes nano-montmorillonite, nano-silica, and cement clinker powder to obtain activated premix; S4 mixes the activated premix, silicate cement, microbial inoculum, urea, and calcium chloride with the modified peat slurry, and then shapes and cures it.

2. The method for solidifying interface-enhanced peat soil according to claim 1, characterized in that, Methods for preparing hydrophobically modified mesoporous silica nanoparticles include: Mesoporous silica nanoparticles are reacted with a silane coupling agent in an ethanol solution at 60-80°C, and then washed and dried to obtain the final product; wherein the amount of silane coupling agent is 5-15% of the mass of the mesoporous silica nanoparticles; and wherein the particle size range of the mesoporous silica nanoparticles is 50-200 nm.

3. The method for solidifying interface-enhanced peat soil according to claim 1, characterized in that, The silane coupling agent is at least one of KH-550, KH-560 and KH-570.

4. The method for solidifying interface-enhanced peat soil according to claim 1, characterized in that, The pre-dispersed liquid has a solid content of 8-10%, and the weight of the pre-dispersed liquid is 8-10% of the dry weight of the peat soil. The concentration of the aqueous solution of the silane coupling agent is 4-6%, and the dosage is 0.5-0.8 times the mass of the pre-dispersion liquid.

5. The method for solidifying interface-enhanced peat soil according to claim 4, characterized in that, The peat soil obtained in step S1 is left to stand at 20~30℃ for 30~60 minutes before proceeding to step S2.

6. The method for solidifying interface-enhanced peat soil according to claim 1, characterized in that, The mass ratio of the nano-montmorillonite, nano-silica and cement clinker powder is 1:1~2:8~18; The nano-montmorillonite has a particle size of 30~100nm, the nano-silica has a particle size of 10~30nm, and the cement clinker powder has a particle size of 1~10μm.

7. The method for solidifying interface-enhanced peat soil according to claim 1, characterized in that, The concentration of Bacillus pasteurellii in the microbial culture was 1×10⁻⁶. 8 ~5×10 8 CFU / mL.

8. The method for solidifying interface-enhanced peat soil according to claim 7, characterized in that, The amounts of each component relative to the dry weight of the peat soil are as follows: silicate cement 30-50%, microbial inoculum 1.5-5.0%, urea and calcium chloride 0.6-2.5%, and activated premix 4.5-12.5%.

9. The method for solidifying interface-enhanced peat soil according to claim 8, characterized in that, The urea and calcium chloride are added in the form of an aqueous solution with a mass of 20-40% and a molar ratio of 1:1-1.

2.

10. The method for solidifying interface-enhanced peat soil according to claim 1, characterized in that, The curing and maintenance method includes: Q1 is cured in a closed environment with a temperature of 25±1℃ and a relative humidity of ≥95% for 18~24h; Q2 Remove the seal and cure in an environment with a temperature of 30±2℃ and a relative humidity of ≥90% for 48~72h; Q3 is cured in a standard curing room at a temperature of 20±2℃ and a relative humidity of ≥95% until the specified age.

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