A method of stabilizing peat

Abstract

The present application relates to peat recycling technical field, especially to a kind of peat's stabilization treatment method, comprising: control peat moisture content to set threshold;Powdered urea-formaldehyde resin and fenton catalyst are added to peat, after mixing, emulsified asphalt is added, after mixing, solidification is obtained to obtain solidification body;Wherein, solidification body inside is along vertical interval and lays the soil film of horizontal placement;Emulsified asphalt is sprayed on the outer surface of solidification body, forms protective layer, carries out long-acting protection;Stable three-dimensional crosslinking network is constructed at molecular level, fundamentally strengthens soil structure, subsequent physical package layer effectively blocks moisture oxygen erosion, significantly delays strength attenuation;Finally, long-acting stability is realized through three-dimensional protection system.

Description

Technical Field

[0001] This invention relates to the field of peat reuse technology, and more particularly to a method for stabilizing peat. Background Technology

[0002] Peat soil, as a soft soil with high organic matter content, has poor engineering properties and is difficult to treat. The core problem lies in the fact that its rich organic components, such as humic acid and fulvic acid, are prone to chemical decomposition and microbial degradation in natural environments, leading to structural damage and significant strength loss. Traditional solidification methods often use inorganic cementing materials such as cement or lime, but these materials easily react adversely with organic matter, inhibiting the hydration process and resulting in low strength and poor long-term stability of the solidified body.

[0003] Currently, the solidification treatment of peat soil mainly uses inorganic cementitious materials such as cement and lime. However, these materials are prone to adverse reactions with organic matter, inhibiting its hydration process and resulting in insufficient strength development and poor long-term stability of the solidified body. Although existing research has attempted to improve the soil using organic chemical agents, there are still many limitations: first, the addition of agents often introduces a large amount of water, offsetting the initial dehydration effect; second, a single solidification mechanism cannot simultaneously achieve the essential strengthening of the microstructure and the long-term stability of macroscopic properties; and third, there is a lack of effective means to block the migration channels of organic matter, making it impossible to construct a complete protective system.

[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 a method for stabilizing peat soil by constructing a stable three-dimensional cross-linked network at the molecular level, which fundamentally strengthens the soil structure. The resulting physical coating layer effectively blocks water and oxygen erosion and significantly delays strength decay. Finally, a three-dimensional protection system is used to achieve long-term stability, 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 stabilizing peat soil includes: S1 controls the moisture content of peat soil to within a set threshold. More specifically, because peat soil has a very high natural moisture content, excessive moisture not only makes the soil in a fluid state, making it difficult to construct, but also significantly dilutes the concentration of subsequently added chemical agents, severely weakening the curing effect. By controlling the moisture content to a set threshold, the soil can reach the optimal plastic state, ensuring the feasibility of mixing and construction. Powdered urea-formaldehyde resin and Fenton catalyst can fully contact and react with organic matter at an effective concentration. S2 adds powdered urea-formaldehyde resin and Fenton catalyst to peat soil, mixes it, adds emulsified asphalt, mixes it again, and then solidifies it to obtain a solidified body. The solidified body contains horizontally placed geomembranes laid at vertical intervals. More specifically, the Fenton catalyst can catalyze the generation of highly active hydroxyl radicals. These hydroxyl radicals preferentially attack the molecular chains of organic matter in the peat soil, generating a large number of new active sites. This promotes the cross-linking polymerization reaction between the hydroxymethyl groups in the urea-formaldehyde resin molecules and the aforementioned active sites, which is beneficial for forming a denser and more stable three-dimensional spatial network structure. This locks easily decomposable organic matter in an inert framework at the molecular level, significantly improving the strength of the solidified body. After the three-dimensional spatial network structure is formed, emulsified asphalt is added. The emulsified asphalt breaks down and spreads on the solidified framework to form a continuous and complete hydrophobic film, which acts as a barrier against oxygen and moisture, cutting off the erosion of the framework by the external environment. More specifically, organic matter decomposition products and water in peat soil tend to migrate vertically under gravity or capillary action. Vertically spaced geomembranes, as horizontal barrier layers, can effectively divide and block migration channels, enhancing the overall structure's ability to resist water intrusion and organic matter migration. S3 sprays emulsified asphalt onto the outer surface of the solidified body to form a protective layer for long-term protection. More specifically, by spraying emulsified asphalt onto the surface of the solidified body, it blocks the intrusion of oxygen in the atmosphere and liquid water on the ground, making up for the deficiencies of internal treatment. In conjunction with the inner protective measures, it delays the aging and strength reduction of materials caused by environmental factors.

[0007] This invention first creates ideal conditions for subsequent treatment by precisely controlling the moisture content; then it adopts a step-by-step stabilization method, first constructing a three-dimensional cross-linked network at the molecular level to achieve the intrinsic stability of organic matter, and then forming a continuous waterproof layer through physical encapsulation; finally, it combines internal geomembrane barrier and surface sealing protection to construct a complete three-dimensional protection system, fundamentally solving the problem of strength attenuation caused by organic matter decomposition and water and oxygen erosion, and achieving simultaneous improvement and long-term maintenance of the strength and durability of the solidified body.

[0008] Furthermore, the method for controlling the moisture content of peat soil is to insert an electrode array into the peat soil to be treated and apply a DC electric field of 0.5~1.5V / cm. More specifically, by applying a DC electric field of 0.5~1.5V / cm to peat soil, a synergistic effect of electrodialysis and electro-oxidation is simultaneously triggered. Electrodialysis drives pore water to migrate directionally to the cathode area and discharge it, achieving efficient dehydration. At the same time, hydroxyl radicals generated in situ near the anode can decompose active components such as small molecule organic acids, which not only eliminates interfering substances in subsequent solidification reactions, but also enhances the reactivity of organic matter through molecular structure pre-activation, achieving the dual effects of physical dehydration and chemical modification.

[0009] Furthermore, the DC electric field is applied intermittently, and the polarity of the electrode array is reversed; More specifically, intermittent operation can effectively dissipate the polarization layer formed at the electrode interface, maintain continuous and efficient dehydration efficiency and reduce energy consumption. Reversing the electrode polarity can promote bidirectional migration of pore water, avoid local water accumulation, improve dehydration uniformity, and effectively overcome common problems in traditional DC electric field treatment such as electrode polarization, uneven dehydration and excessive energy consumption.

[0010] Preferably, the parameters for the intermittent mode are: power on for 20-40 minutes followed by power off for 5-15 minutes.

[0011] Furthermore, the geomembrane has a thickness of 0.5~2mm and is made of polyethylene.

[0012] More specifically, the geomembrane is made of polyethylene with a thickness of 0.5 to 2 mm. The above thickness range can give the membrane sufficient mechanical strength to resist construction impact and soil stress, while maintaining good flexibility to adapt to foundation deformation. Preferably, the polyethylene used is high-density polyethylene, which has a highly dense, non-porous structure and a completely non-polar hydrocarbon skeleton. It not only physically blocks the migration of water and dissolved organic matter through extremely low permeability, but also resists the erosion and dissolution of organic acids by utilizing stable chemical properties.

[0013] Furthermore, the amount of powdered urea-formaldehyde resin added is determined by the following formula: M = k1 × (m × R); Where M is the amount of powdered urea-formaldehyde resin added, k1 is the replenishment coefficient, m is the mass of active organic matter to be fixed in the peat soil to be treated, and R is the average molar reaction coefficient between urea-formaldehyde resin and active organic matter.

[0014] More specifically, by multiplying m by R, the theoretical amount of urea-formaldehyde resin required for complete reaction is determined; and by introducing a correction coefficient k1, the ideal laboratory conditions and on-site construction are incorporated into the calculation system, so that the theoretical value is calibrated by practice, and finally the calculation result M simultaneously meets the dual requirements of sufficient chemical reaction and reliable engineering strength.

[0015] Preferably, the calculation method for R is as follows: First, humic acid, fulvic acid, and other major active organic substances are separated from the peat soil to be treated, and their molar reaction coefficients with urea-formaldehyde resin are determined respectively; then, based on the actual molar proportions of each major active organic substance in the peat soil, the molar reaction coefficients are weighted and averaged to obtain the average molar reaction coefficient of the peat soil. The calculation formula is:

[0016] Among them, R i Let n be the molar reaction coefficient between the i-th active organic matter and the urea-formaldehyde resin. i denoted as the molar amount of the i-th active organic matter in peat soil.

[0017] Preferably, k1 is calculated by performing a curing test on the theoretical amount of powdered urea-formaldehyde resin calculated using the aforementioned method when k1=1 under laboratory conditions, and verifying its effectiveness by testing the unconfined compressive strength of the cured body; if the strength does not meet the design standard, the test is repeated by gradually increasing the k1 value according to a certain gradient until the strength meets the standard and the k1 value with the best economic efficiency is determined, and this value is the supplementary coefficient under this process condition; Unconfined compressive strength is a core indicator for evaluating the solidification effect in geotechnical engineering. It can comprehensively reflect the formation quality of three-dimensional network structures and is also directly related to the actual load-bearing requirements of engineering projects. Therefore, measuring unconfined compressive strength is used as the standard for measuring k1.

[0018] Furthermore, the solid content of the emulsified asphalt in step S2 is 55-65%; more specifically, the emulsified asphalt with the above solid content has sufficient fluidity to achieve uniform mixing with the soil, and also ensures that a sufficient amount of continuous asphalt film can be formed after demulsification to provide an effective waterproof barrier. In addition to the effective solids of asphalt, the remaining components of the emulsified asphalt are mainly water and a small amount of emulsifier. The water evaporates or is absorbed by the soil during the demulsification process, while the emulsifier plays the role of maintaining the stability of the emulsion and promoting the demulsification and film formation. The volume of emulsified asphalt added in step S2 is determined by the following formula: V1 = k2 × (V2 × β) / s; Where V1 is the added volume of emulsified asphalt, k2 is the correction coefficient, V2 is the total pore volume of peat soil after step S1, β is the target filling degree of effective solids in asphalt, with a value of 0.3~0.6; and s is the solid content of emulsified asphalt.

[0019] More specifically, the above calculation method calculates the theoretical volume of pore space that needs to be filled by effective asphalt solids through the multiplication operation of V2 and β; then, by dividing by the solid content, the volume of effective asphalt solids is converted into the volume of emulsified asphalt slurry containing water and emulsifier; finally, by multiplying the correction coefficient, it compensates for actual factors such as uneven material distribution and demulsification rate fluctuations during the construction process, and achieves accurate conversion from theoretical filling requirements to actual engineering usage.

[0020] Preferably, the formula for calculating V2 is: ; Among them, V 总 The total volume of peat soil after step S1 is given. The dry density after S1 treatment (measured on-site using the ring cutter method). This refers to the specific gravity of soil particles (determined in the laboratory). Let be the density of water; the above formula determines the volume ratio of solid particles in the soil by the ratio of dry density to soil particle specific gravity, and then the total pore volume can be accurately derived by subtracting the solid volume from the total volume.

[0021] Preferably, the target filling degree is mainly affected by three factors: the complexity of the pore structure of peat soil, the engineering seepage prevention level requirements, and the characteristics of emulsified asphalt materials. Its acquisition requires a systematic experimental verification method, that is, a series of samples with different β values ​​are prepared in the laboratory, and their permeability coefficient and mechanical strength are tested simultaneously after curing. Finally, the optimal value that simultaneously meets the seepage prevention threshold requirements and the asphalt usage is selected as the design basis.

[0022] Furthermore, the Fenton catalyst is at least one of ferrous sulfate, ferrous chloride, and ferrous nitrate, and its addition amount is 0.05 to 0.2% of the dry weight of the peat soil.

[0023] More specifically, the aforementioned ferrous salts can rapidly dissolve in soil pore water, releasing highly active Fe. 2+ It effectively initiates the Fenton reaction chain to generate strong oxidizing hydroxyl radicals. The lower limit of 0.05% ensures sufficient catalysis of the activation sites of organic matter, while the upper limit of 0.2% avoids the negative disturbance of soil structure by excessive iron ions and the ineffective increase in reagent cost.

[0024] Furthermore, the vertical spacing of the geomembrane is 40~60cm; More specifically, the aforementioned size range can effectively divide peat soil through geomembrane, limiting its diffusion range, and can also avoid material waste and increased construction disturbance caused by excessively small spacing.

[0025] Furthermore, in step S3, the spraying dosage of emulsified asphalt is 1.0~2.0 kg / m³. 2 The resulting protective layer has a thickness of 1.5~3mm; More specifically, the above dosage range ensures the formation of a continuous, defect-free, dense waterproof membrane while avoiding material waste or the risk of layer slippage due to excessive spraying; the above thickness range provides sufficient durability reserves to resist environmental erosion while maintaining effective adhesion to the base soil.

[0026] Furthermore, the threshold is set at 40-60%; More specifically, the above range precisely corresponds to the critical interval in which peat soil transitions from a fluid to a plastic state, eliminating the difficulties in mixing and the problem of reagent dilution caused by excessively high moisture content, while avoiding dust and lack of reaction medium caused by excessively low moisture content.

[0027] The technical solution of this invention can achieve the following technical effects: First, by applying a DC electric field to peat soil, a synergistic effect of electrodialysis and electrooxidation is generated. The electrodialysis effect drives the directional migration of pore water, accurately reducing the moisture content of peat soil to within a set threshold, creating ideal conditions for subsequent stabilization treatment. At the same time, the hydroxyl radicals generated in situ near the anode can preferentially decompose active components such as small molecule organic acids, eliminating interfering substances in the subsequent curing reaction. Furthermore, by changing the molecular structure of organic matter, it becomes a pre-activation site for the cross-linking reaction with the curing agent. In the stabilization stage, a stepwise process is used to achieve chemical fixation and physical encapsulation. First, the powdered urea-formaldehyde resin, under the action of Fenton catalyst, attacks the humic acid molecular chain with new active sites through the hydroxyl radicals generated by catalyst activation. This significantly increases the cross-linking density of hydroxymethyl groups and functional groups such as phenolic hydroxyl and amino groups in the resin molecules, forming a dense three-dimensional network framework. This process achieves the intrinsic stability of organic matter at the molecular level. After the chemical cross-linking network is basically formed, the emulsified asphalt added can fully demulsify and spread on the fixed framework to form a continuous and complete hydrophobic encapsulation film, effectively avoiding the physical obstruction of the asphalt film to the previous chemical reaction.

[0028] In the long-term protection phase, the internal vertically spaced geomembrane layers effectively divide and block the migration channels of organic matter. Combined with the protective layer formed by surface emulsified asphalt, they form a three-dimensional protection system at the macro scale, ultimately achieving comprehensive protection from molecular-scale chemical cross-linking to macro-structural physical barrier, thus solving the problem of strength reduction in peat solidified bodies caused by organic matter decomposition and water and oxygen intrusion. Attached Figure Description

[0029] 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.

[0030] Figure 1 This is a schematic flowchart of the peat stabilization treatment method of the present invention. Detailed Implementation

[0031] 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.

[0032] 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.

[0033] 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.

[0034] Example 1:

[0035] This embodiment provides a method for stabilizing peat soil, the process of which is as follows: Project Overview and Parameter Measurement: The total volume of a peat remediation project site is 0.1 m³. 3 The dry density of peat soil after S1 electrochemical pretreatment was determined by on-site ring sampler method. 480kg / m 3 The specific gravity of soil particles was measured in the laboratory. The value was 1.55. The organic matter content was determined to be 58% of the dry soil weight by loss on ignition method. The molar ratio of humic acid to fulvic acid was determined to be 6:4, and their characteristic molar reaction coefficients with urea-formaldehyde resin were 0.22 and 0.28, respectively.

[0036] Material proportion calculation: Calculation of total active organic matter: m = 0.1m 3 ×480kg / m 3 ×58%=27.84kg; Calculation of average molar reaction coefficient: R = (0.22 × 6 + 0.28 × 4) / (6 + 4) = 0.244; Determining the amount of urea-formaldehyde resin to be added (taking k1=1.2): M=1.2×(27.84×0.244)=8.152kg; In step S23, the amount of emulsified asphalt used is calculated. The emulsified asphalt used is a cationic slow-cracking emulsified asphalt (CSS-1h) with a solid content of 60%. Its composition is: 60% asphalt, 39% water, and 1% hexadecyltrimethylammonium bromide emulsifier. Pore ​​volume V2 = 0.1 × [1 - 480 / (1.55 × 1000)] = 0.069 m 3 ; Taking β=0.45, k2=1.1, and s=60%, then: V1=1.1×(0.069×0.45) / 0.6=0.0569m 3 ; Fenton catalyst dosage: Take 0.1% of the dry weight of peat soil in ferrous sulfate heptahydrate: 0.1 × 480 × 0.1% = 0.048 kg; Construction process: S1 controls the peat soil moisture content to within a set threshold; More specifically, using an electrode array with a spacing of 20 cm, applying a DC electric field of 1.2 V / cm, and operating intermittently with power on for 30 min and power off for 10 min, the moisture content decreased from the initial 210% to 52% after 48 h; S2 adds powdered urea-formaldehyde resin and Fenton catalyst to peat soil, mixes it, adds emulsified asphalt, mixes it, and then solidifies it to obtain a solidified body; wherein, horizontal geomembrane is laid at intervals along the vertical direction inside the solidified body. More specifically, the steps are as follows: First, add 8.152 kg of powdered urea-formaldehyde resin and 48 g of ferrous sulfate heptahydrate to S21, and mechanically mix for 25 min. S22 The well-mixed soil is transferred into a standard curing mold and left to cure for 3 hours at a temperature of 20±2℃ and a humidity of ≥95% to complete the construction of a three-dimensional cross-linked network. Add 56.9L of emulsified asphalt to S23 and mix it twice at the same speed for 15 minutes until uniform; S24 The mixture is filled into the mold in layers. For every 50cm thickness, a 1.0mm thick HDPE geomembrane is laid manually. A total of 3 layers are laid, corresponding to a total height of 150cm. Finally, the mixture is compacted and shaped under a static pressure of 2MPa to obtain a solidified body. S3 sprays emulsified asphalt onto the outer surface of the solidified body to form a protective layer for long-term protection; More specifically, 24 hours after the cured body has formed and has achieved initial strength, immediately spray it evenly with a sprayer at a concentration of 1.8 kg / m³. 2 The emulsified asphalt was naturally dried to form a continuous protective layer of 2.5 mm thickness; then it was placed in a standard curing room with a temperature of 20±2℃ and a humidity of ≥95% for 28 days.

[0037] Example 2:

[0038] This embodiment provides a method for stabilizing peat soil, the process of which is as follows: Project Overview and Parameter Measurement: The total volume of a peat remediation project site is 0.1 m³. 3 The dry density of peat soil after S1 electrochemical pretreatment was determined by on-site ring sampler method. 500kg / m 3 The specific gravity of soil particles was measured in the laboratory. The value was 1.6. The organic matter content was determined to be 55% of the dry soil weight by loss on ignition method. The molar ratio of humic acid to fulvic acid was determined to be 7:3, and their characteristic molar reaction coefficients with urea-formaldehyde resin were 0.21 and 0.29, respectively.

[0039] Material proportion calculation: Calculation of total active organic matter: m = 0.1m 3 ×500kg / m 3 ×58%=27.5kg; Calculation of average molar reaction coefficient: R = (0.21 × 7 + 0.29 × 3) / (7 + 3) = 0.234; Determining the amount of urea-formaldehyde resin to be added (taking k1=1.15): M=1.15×(27.5×0.234)=7.4kg; In step S23, the amount of emulsified asphalt used is calculated. The emulsified asphalt used is a cationic slow-cracking emulsified asphalt (CSS-1h) with a solid content of 60%. Its composition is: 58% asphalt, 40.5% water, and 1.5% hexadecyltrimethylammonium bromide emulsifier. Pore ​​volume V2 = 0.1 × [1 - 500 / (1.6 × 1000)] = 0.06875 m³ 3 ; Taking β=0.5, k2=1.05, and s=58%, then: V1=1.05×(0.06875×0.5) / 0.58=0.062m 3 ; Fenton catalyst dosage: Take 0.08% of the dry weight of peat soil in ferrous sulfate heptahydrate: 0.1 × 500 × 0.1% = 0.04 kg; Construction process: S1 controls the peat soil moisture content to within a set threshold; More specifically, using an electrode array with a spacing of 20 cm, applying a DC electric field of 1.2 V / cm, and operating intermittently with power on for 30 min and power off for 10 min, the moisture content decreased from the initial 220% to 55% after 52 h; S2 adds powdered urea-formaldehyde resin and Fenton catalyst to peat soil, mixes it, adds emulsified asphalt, mixes it, and then solidifies it to obtain a solidified body; wherein, horizontal geomembrane is laid at intervals along the vertical direction inside the solidified body. More specifically, the steps are as follows: S21 is first added with 7.4 kg of powdered urea-formaldehyde resin and 40 g of ferrous sulfate heptahydrate, and mechanically stirred for 25 min. S22 The well-mixed soil is transferred into a standard curing mold and left to cure for 3 hours at a temperature of 20±2℃ and a humidity of ≥95% to complete the construction of a three-dimensional cross-linked network. Add 62.5L of emulsified asphalt to S23 and mix it twice at the same speed for 15 minutes until it is uniform. S24 The mixture is filled into the mold in layers. For every 40cm thickness, a 1.2mm thick HDPE geomembrane is laid manually. A total of 3 layers are laid, corresponding to a total height of 120cm. Finally, it is compacted and shaped with a static press under a pressure of 2MPa to obtain a solidified body. S3 sprays emulsified asphalt onto the outer surface of the solidified body to form a protective layer for long-term protection; More specifically, 24 hours after the cured body has formed and has achieved initial strength, immediately spray it evenly with a sprayer at a concentration of 1.5 kg / m². 2 The emulsified asphalt described above is naturally dried to form a continuous protective layer with a thickness of 2.0 mm; then it is placed in a standard curing room with a temperature of 20±2℃ and a humidity of ≥95% for 28 days.

[0040] Example 3:

[0041] Unlike Example 2, the Fenton catalyst was replaced with ferrous chloride.

[0042] Comparative Example 1: Take the same peat soil sample as in Example 1, with a total volume of 0.1 m³. 3 The initial moisture content was 210%. Ordinary Portland cement (42.5 grade) was used as the curing material, added at a conventional dosage of 15% of the dry weight of the peat soil. 7.2 kg of cement was mechanically mixed with peat moss for 25 minutes, then layered into molds and compacted under a pressure of 2 MPa. The specimens were cured in a standard curing room (20 ± 2℃, humidity ≥ 95%) for 28 days.

[0043] Comparative Example 2: Unlike Example 1, this comparative example uses the following method to reduce the water content of peat soil: vacuum preloading is used instead of electrochemical pretreatment for dehydration, that is, drainage boards and vacuum membranes are laid on the surface of peat soil, and vacuum is applied to a vacuum degree of -80 kPa for 48 hours, so that the water content is reduced from 210% to 52%, the same as in Example 1.

[0044] Comparative Example 3: Unlike Example 1, this comparative example did not have a geomembrane laid.

[0045] Comparative Example 4: Unlike Example 1, this comparative example did not spray the emulsified asphalt in step S3.

[0046] Comparative Example 5: Unlike Example 1, this comparative example did not use emulsified asphalt for physical encapsulation in step S2.

[0047] The following tests were performed on the examples and comparative examples, and the results are shown in Table 1. The test content is as follows: According to the "Standard for Geotechnical Testing Methods" (GB / T50123), the specimens cured for 28 days were made into cylindrical specimens with a diameter of 50 mm and a height of 100 mm. They were continuously loaded on a universal testing machine at an axial strain rate of 1 mm / min, and the peak stress at the time of specimen failure was recorded as the unconfined compressive strength.

[0048] Using a flexible wall permeameter, the sample was made into a standard specimen with a diameter of 61.8 mm and a height of 40 mm. A variable head permeameter test was conducted under a confining pressure of 100 kPa and a head difference of 50 kPa. The permeability coefficient was calculated based on the time-head change relationship.

[0049] Table 1. Test results of the examples and comparative examples.

[0050] In Comparative Example 1, the cement hydration products in the traditional cement solidification method react adversely with organic matter such as humic acid in peat soil. This not only inhibits the normal hydration process of cement, but also generates a large amount of loose calcium-humic acid complex, which seriously damages the compactness of the soil structure, resulting in insufficient strength development and significantly higher permeability of the solidified body.

[0051] In Comparative Example 2, although the vacuum pre-compression method can achieve physical dehydration, it completely lacks the key role of electrochemical pre-oxidation. It fails to decompose small molecule organic acids and pre-activate the molecular structure of organic matter, which greatly reduces the efficiency and extent of the subsequent Fenton catalytic cross-linking reaction. It cannot form a sufficiently dense three-dimensional network skeleton, thus affecting the overall performance of the final cured body.

[0052] In Comparative Example 3, due to the absence of an internal geomembrane and the lack of a horizontal three-dimensional barrier layer, the vertical migration channels of water and organic matter decomposition products could not be effectively separated and blocked. As a result, potential erosion paths still existed inside the solidified body, leading to its long-term stability and impermeability being significantly inferior to that of the complete protection system.

[0053] In Comparative Example 4, the lack of a surface emulsified asphalt sealing layer exposes the cured body directly to the external environment, allowing atmospheric oxygen and liquid water to easily penetrate. This not only accelerates the oxidative aging of the surface material but also penetrates deep into the interior through capillary action, damaging the chemical cross-linking structure. Consequently, the cured body exhibits a significant edge effect and suffers from severe overall inadequacy in durability.

[0054] In Comparative Example 5, due to the lack of a continuous hydrophobic coating film formed by emulsified asphalt, the internal pores of the solidified body are directly exposed to the environment. Moisture and oxygen can easily penetrate and destroy the formed chemical cross-linking network, resulting in a strength retention rate of only 70% of that in Example 1, and the permeability coefficient increases by about 200 times. The physical coating layer plays an irreplaceable role in maintaining long-term stability.

[0055] 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 stabilizing peat soil, characterized in that, include: S1 controls the peat soil moisture content to within a set threshold; S2 adds powdered urea-formaldehyde resin and Fenton catalyst to peat soil, mixes it, adds emulsified asphalt, mixes it, and then solidifies it to obtain a solidified body; wherein, the solidified body is filled with horizontally placed geomembranes at vertical intervals inside. S3 sprays emulsified asphalt onto the outer surface of the solidified body to form a protective layer for long-term protection.

2. The method for stabilizing peat soil according to claim 1, characterized in that, The method for controlling the moisture content of peat soil is to insert an electrode array into the peat soil to be treated and apply a DC electric field of 0.5~1.5V / cm.

3. The method for stabilizing peat soil according to claim 2, characterized in that, The DC electric field is applied intermittently, and the polarity of the electrode array is reversed.

4. The method for stabilizing peat soil according to claim 1, characterized in that, The geomembrane has a thickness of 0.5~2mm and is made of polyethylene.

5. The method for stabilizing peat soil according to claim 1, characterized in that, The amount of powdered urea-formaldehyde resin added is determined by the following formula: M = k1 × (m × R); Where M is the amount of powdered urea-formaldehyde resin added, k1 is the replenishment coefficient, m is the mass of active organic matter to be fixed in the peat soil to be treated, and R is the average molar reaction coefficient between urea-formaldehyde resin and active organic matter.

6. The method for stabilizing peat soil according to claim 5, characterized in that, The solid content of the emulsified asphalt in step S2 is 55-65%; The volume of emulsified asphalt added in step S2 is determined by the following formula: V1 = k2 × (V2 × β) / s; Wherein, V1 is the added volume of emulsified asphalt, k2 is the correction coefficient, V2 is the total pore volume of peat soil after step S1, β is the target filling degree of effective solids in asphalt, with a value of 0.3~0.6; and s is the solid content of the emulsified asphalt.

7. The method for stabilizing peat soil according to claim 1, characterized in that, The Fenton catalyst is at least one of ferrous sulfate, ferrous chloride, and ferrous nitrate, and its addition amount is 0.05 to 0.2% of the dry weight of peat soil.

8. The method for stabilizing peat soil according to claim 1, characterized in that, The geomembrane is laid at vertical intervals of 40-60cm.

9. The method for stabilizing peat soil according to claim 1, characterized in that, In step S3, the spraying dosage of emulsified asphalt is 1.0~2.0 kg / m³. 2 The resulting protective layer has a thickness of 1.5~3mm.

10. The method for stabilizing peat soil according to claim 1, characterized in that, The set threshold is 40-60%.

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