Nano liquid soil stabilizer as well as preparation and application thereof

Abstract

The invention provides a nano liquid soil stabilizer as well as preparation and application thereof. The nano liquid soil stabilizer comprises 6-20 parts of a modifier; 4-20 parts of a stabilizer; 0.5 to 2 parts of nano particles; 10 to 20 parts of an active agent; 1-2 parts of an ion stabilizer; 2-11 parts of a dispersant; 2-15 parts of an accelerant; the stabilizer comprises one or more of isopropanol, ethanol, propylene glycol and ethylene glycol; the nano particles comprise silicon dioxide or aluminum oxide with the particle size of 10-100 nm; the ion stabilizer is one or more of sodium chloride, potassium chloride and sodium sulfate; the accelerant is one or more of triethanolamine oleate, triethanolamine, isopropanolamine and diethanol amine. The soil stabilizer is composed of the specific stabilizer, the nano particles, the ion stabilizer and the accelerant, the organic modifier containing polar groups is introduced, the specific organic modifier is adsorbed and acts on the surfaces of the nano particles by means of intermolecular force, the dispersion effect of the organic modifier is improved, the compactness of soil is remarkably promoted, and the mechanical strength and water stability of the soil are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of soil solidifying agents, and in particular to a nano liquid soil solidifying agent and a preparation and application thereof. Background Art

[0002] As a new type of building material, soil solidifiers can carry out a series of physical and chemical reactions on the abundant soil. After consolidation and reaching a certain strength and stability, they can be used as various road engineering materials. According to the form of soil solidifiers, they can be divided into inorganic powder solidifiers and organic liquid solidifiers. Early soil solidifiers were mainly based on powdered cement and lime. In engineering practice, it was found that cement-lime soil had low strength, poor shrinkage resistance, low roadbed density, and poor water stability of solidified soil. This results in short maintenance intervals and high maintenance costs, and also affects the use of roads. The method of adding admixtures to the cement matrix to improve the strength of cement-solidified soil has attracted widespread attention.

[0003] Chinese invention patent publication number CN115785965 improves soil strength by adding an alkaline early strength agent to the soil. Chinese invention patent publication number CN102676176 adds concentrated sulfuric acid along with a dispersant and an activator to create an ionic liquid soil stabilizer. However, these substances can also acidify or alkalinize the soil, leading to the influx of acidic or alkaline substances into groundwater and soil, posing a high risk of soil and water contamination.

[0004] Chinese invention patent publication number CN113637485A discloses a polymeric liquid soil solidifier comprising glycerol, peregal, carboxymethyl cellulose, sodium sulfate of fatty alcohol polyoxyethylene ether, magnesium chloride, and magnesium sulfate. While the cross-linked network structure and ion exchange produced by the polymeric materials, along with the surfactant's ability to reduce surface tension, improves the stability of the solidified soil, its strength improvement is limited. Therefore, there is a need for a highly stable soil solidifier to enhance soil strength and stability. Summary of the Invention

[0005] The object of the present invention is to provide a nano-liquid soil solidifier having high stability; another object of the present invention is to provide the preparation and application of the nano-liquid soil solidifier.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A nano liquid soil solidifying agent comprises the following raw materials in parts by weight:

[0008] 6-20 parts of modifier; 4-20 parts of stabilizer; 0.5-2 parts of nanoparticles; 10-20 parts of active agent; 1-2 parts of ionic stabilizer; 2-11 parts of dispersant; 2-15 parts of accelerator; 40-60 parts of aqueous solvent;

[0009] The stabilizer comprises one or more components of isopropyl alcohol, ethanol, propylene glycol and ethylene glycol;

[0010] The nanoparticles comprise silicon dioxide or aluminum oxide, and the nanoparticle size ranges from 10 to 100 nm;

[0011] The ion stabilizer is one or more components of sodium chloride, potassium chloride, and sodium sulfate;

[0012] The accelerator is one or more components of triethanolamine oleate, triethanolamine, isopropanolamine, and diethanolamine.

[0013] Furthermore, the nano-liquid soil solidifier further comprises 40 to 60 parts by weight of solvent water.

[0014] Furthermore, the stabilizer is isopropyl alcohol and propylene glycol, and the ratio of isopropyl alcohol to propylene glycol is 3:1.

[0015] Furthermore, the nanoparticles are silicon dioxide or aluminum oxide, and the particle size of the silicon dioxide and aluminum oxide nanoparticles is 10-100 nm. Preferably, the particle size of the silicon dioxide and aluminum oxide nanoparticles is 10-20 nm.

[0016] Furthermore, the ion stabilizers are sodium sulfate and potassium chloride, and the ratio of sodium sulfate to potassium chloride is 1:1.

[0017] Furthermore, the promoter is triethanolamine oleate and triethanolamine; the ratio of triethanolamine oleate and triethanolamine is 2:1.

[0018] Furthermore, the modifier is composed of the following components in mass fraction: 40% Span 85, 50% Span 80 and 10% sulfonic acid; the active agent is composed of the following components in mass fraction: 50% sodium dodecyl diphenyl ether disulfonate, 45% sodium long-chain carboxylate polyoxyethylene sulfonate and 5% sodium fatty acid methyl ester sulfonate; the dispersant is composed of the following components in mass fraction: 55% fatty alcohol polyoxyethylene ether and 45% dodecylphenol polyoxyethylene ether.

[0019] Furthermore, the preparation method of the nano liquid soil solidifying agent comprises the following steps:

[0020] S1. The nanoparticles and modifier were sequentially dispersed in water at 50-60°C to form a mixture, stirred at 300-500 rpm for 1 hour, and then ultrasonicated at 600 W for 30 minutes to obtain dispersion 1.

[0021] S2. Add the active agent and ion stabilizer to the dispersion 1 at 50~60°C in sequence and stir at a speed of 300~500 r / min for 2~4 hours to obtain dispersion 2;

[0022] S3. The dispersant fatty alcohol polyoxyethylene ether was added to the dispersion 2, and after stirring and dissolving, the dispersant dodecylphenol polyoxyethylene ether was added dropwise, wherein the addition rate was 1 to 3 d / s, the stirring speed was 150 to 400 r / min, to obtain a dispersion 3;

[0023] S4. Add the accelerator dropwise to the dispersion 3 at a dropping speed of 1 to 3 d / s and stir at a speed of 200 to 400 r / min for 1 to 2 hours to obtain a nano-liquid soil solidifier.

[0024] The present invention seeks to protect the use of the nano-liquid soil solidifier in solidifying soil.

[0025] Furthermore, the soil solidifying agent is diluted with water and then sprayed into the dry mixture containing dry soil, mixed evenly, and rolled until flat; the ratio of the soil solidifying agent to the dry soil is 1:5000~1:500.

[0026] Furthermore, the dry mix is ​​prepared by adding 2-8% quicklime and 3-8% Portland cement by relative mass to soil material, and mixing the mixture evenly with a road mixer; the quicklime needs to be added in advance, and the mixture is stewed for 3-7 days.

[0027] Preferably, the rolling until flat is to use a roller to roll, flatten, and partially repair the roadbed, and repeat this process until flat; after each layer of solidified soil is rolled, it is roughened, watered, and maintained for no less than 7 days.

[0028] Compared with the existing technology, the present invention has the following beneficial effects:

[0029] The nanometer liquid soil solidifier provided by the present invention contains a liquid soil solidifier with uniformly dispersed nanoparticles. By introducing an organic modifier containing a polar group into the liquid soil solidifier and utilizing intermolecular forces to adsorb and act on the surface of nano-silicon dioxide particles, the nanoparticles are well dispersed in the dispersion, and finally a well-dispersed novel liquid nanometer soil solidifier is prepared. The liquid nanometer soil solidifier can promote the cement hydration process in the soil and fill the pores of the solidified soil after compaction, thereby increasing its compactness and significantly improving the mechanical strength and water stability of the solidified and stabilized soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a SEM photograph of the cured soil specimen of Example 1 at a magnification of 5000 times at the age of 6+1 days.

[0031] Figure 2 This is an SEM photograph of the cured soil specimen of comparative example 1 at 5000 times the age of 6+1 days.

[0032] Figure 3 This is the SEM photo of the blank control cured soil specimen at 5000 times the age of 6+1 days. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The materials mentioned in the examples are commercially available unless otherwise specified, and the techniques used are commonly used in the art unless otherwise specified.

[0034] Example 1

[0035] This embodiment provides a nano-liquid soil solidifying agent, comprising the following components:

[0036] Raw materials: 46 kg water, 10 kg stabilizer (isopropyl alcohol: propylene glycol = 3:1), 10 kg modifier, 1 kg nano-silica (particle size 20 nm), 13 kg active agent, 2 kg ion stabilizer (sodium sulfate: potassium chloride = 1:1), 9 kg dispersant, 9 kg accelerator (triethanolamine oleate: triethanolamine = 2:1).

[0037] The nano-liquid soil solidifier of this example was prepared by the following method: the aforementioned nanoparticles and modifier were dispersed in a 55°C water mixture at a ratio of 1:10, stirred at 300 r / min for 1 hour, and then sonicated in a 600 W ultrasonic device for 30 minutes to obtain Dispersion 1. An active agent and an ion stabilizer were sequentially added to Dispersion 1 at 50°C, and stirred at 400 r / min for 2 hours to obtain Dispersion 2. Fatty alcohol polyoxyethylene ether was added to Dispersion 2, and after stirring and dissolving, dodecylphenol polyoxyethylene ether was added dropwise at a rate of 1 d / s and a stirring rate of 300 r / min to obtain Dispersion 3. An accelerator was added dropwise to Dispersion 3 at a rate of 3 d / s, and stirred at 350 r / min for 2 hours to obtain the novel nano-liquid soil solidifier.

[0038] When soil solidifier is used in base road construction, 2-8% quicklime and 3-8% Portland cement by relative mass can be added to the soil material and mixed evenly using a road mixer. In this embodiment, 3% quicklime and 5% Portland cement are preferred. The quicklime needs to be added in advance and the material is stewed for 5 days. The ratio of soil solidifier to dry soil can be 1:5000-1:500, and in this embodiment, 1:600 ​​is preferred.

[0039] Comparative Example 1

[0040] The preparation method is the same as that of Example 1, except that the nanoparticles are not present, and the other components remain unchanged.

[0041] Comparative Example 2

[0042] The preparation method is the same as that of Example 1, except that the nanoparticles are 1 kg of silicon dioxide nanoparticles with a particle size of 500 nm, and the other components remain unchanged.

[0043] Comparative Example 3

[0044] The preparation method is the same as that of Example 1, except that the mass of the nanoparticles is 3 kg of silicon dioxide nanoparticles, the particle size remains unchanged, and the other components remain unchanged.

[0045] Example 2

[0046] The preparation method is the same as that of Example 1, except that the nanoparticles have a mass of 1 kg, are composed of equal proportions of silicon dioxide and aluminum oxide, have a particle size of 20 nm, and the other components remain unchanged.

[0047] Example 3

[0048] The preparation method is the same as that of Example 1, except that the mass of the silicon dioxide nanoparticles is 2 kg and the particle size is 20 nm, and the other components remain unchanged.

[0049] Example 4

[0050] The preparation method is the same as that of Example 1, except that the mass of the silica nanoparticles is 0.5 kg and the particle size is 20 nm. The other components remain unchanged.

[0051] Example 5

[0052] The preparation method is the same as that of Example 1, except that the nanoparticles are 1 kg of aluminum oxide nanoparticles with a particle size of 20 nm, and the other components remain unchanged.

[0053] Example 6

[0054] The preparation method is the same as that of Example 1, except that the nanoparticles are 1 kg of silicon dioxide nanoparticles with a particle size of 10 nm, and the other components remain unchanged.

[0055] Example 7

[0056] The preparation method is the same as that of Example 1, except that the nanoparticles are 1 kg of silicon dioxide nanoparticles with a particle size of 100 nm, and the other components remain unchanged.

[0057] Comparative Example 4

[0058] The preparation method is the same as that of Example 1, except that no modifier is used and the other components remain unchanged.

[0059] Example 8

[0060] The preparation method is the same as that of Example 1, except that the mass of the modifier is 20 kg, the composition of the modifier remains unchanged, and the other components also remain unchanged.

[0061] Example 9

[0062] The preparation method is the same as that of Example 1, except that the mass of the active agent is 20 kg, the composition of the active agent remains unchanged, and the other components also remain unchanged.

[0063] Comparative Example 5

[0064] The preparation method is the same as that of Example 1, except that the active agent is omitted and the other components remain unchanged.

[0065] Comparative Example 6

[0066] The preparation method is the same as that of Example 1, except that the active agent is omitted and the mass of the dispersant component is changed to 12 kg, while the other components remain unchanged.

[0067] Example 10

[0068] The preparation method is the same as that of Example 1, except that the mass of the dispersant is 11 kg, the composition of the dispersant remains unchanged, and the other components also remain unchanged.

[0069] Comparative Example 7

[0070] The preparation method is the same as that of Example 1, except that the dispersant is omitted and the other components remain unchanged.

[0071] Example 11

[0072] The preparation method is the same as that of Example 1, except that the accelerator is triethanolamine oleate of the same mass, and the other components remain unchanged.

[0073] Comparative Example 8

[0074] The preparation method is the same as that of Example 1, except that the accelerator is omitted and the other components remain unchanged.

[0075] Comparative Example 9

[0076] The preparation method is the same as that of Example 1, except that the accelerator is 16 kg, the accelerator composition remains unchanged, and other components remain unchanged.

[0077] Example 12

[0078] The preparation method is the same as that of Example 1, except that the accelerator is 2 kg, the accelerator composition remains unchanged, and other components remain unchanged.

[0079] Comparative Example 10

[0080] The preparation method is the same as that of Example 1, except that the stabilizer is 21 kg, the stabilizer composition remains unchanged, and other components remain unchanged.

[0081] Comparative Example 11

[0082] The preparation method is the same as that of Example 1, except that the stabilizer is 3 kg, the stabilizer composition remains unchanged, and other components remain unchanged.

[0083] Example 13

[0084] The preparation method is the same as that of Example 1, except that the stabilizer is 15 kg, the stabilizer composition remains unchanged, and other components remain unchanged.

[0085] Example 14

[0086] The preparation method is the same as that of Example 1, except that the stabilizer is equal mass of isopropyl alcohol and ethylene glycol, the mass ratio of isopropyl alcohol to ethylene glycol is 2:1, and other components remain unchanged.

[0087] Example 15

[0088] The present example provides a nano-liquid soil stabilizer, which comprises the following components:

[0089] Raw materials: 40 kg of water, 15 kg of stabilizer (isopropyl alcohol: propylene glycol = 3:1), 6 kg of modifier, 2 kg of nano-silicon dioxide (particle size of 20 nm), 20 kg of active agent, 1 kg of ion stabilizer (sodium sulfate: potassium chloride = 1:1), 7 kg of dispersant, and 9 kg of accelerator (oleic acid triethanolamine: triethanolamine = 2:1).

[0090] The preparation method and construction of the nano-liquid soil stabilizer of the present example are the same as those of Example 1.

[0091] Example 16

[0092] The present example provides a nano-liquid soil stabilizer, which comprises the following components:

[0093] Raw materials: 46 kg water, 15 kg stabilizer (isopropyl alcohol: ethylene glycol = 3:1), 10 kg modifier, 1 kg nano-silica (particle size 100 nm), 13 kg active agent, 1 kg ion stabilizer (sodium chloride), 11 kg dispersant, 9 kg accelerator (triethanolamine oleate: triisopropanolamine = 1:1).

[0094] The preparation method and construction of the nano-liquid soil solidifier in this embodiment are the same as those in Example 1.

[0095] Example 17

[0096] This embodiment provides a nano-liquid soil solidifying agent, comprising the following components:

[0097] Raw materials: 50 kg water, 4 kg stabilizer (isopropyl alcohol), 10 kg modifier, 2 kg nano-silica (particle size 10 nm), 20 kg active agent, 2 kg ion stabilizer (sodium sulfate: potassium chloride = 1:1), 7 kg dispersant, 5 kg promoter (triethanolamine oleate).

[0098] The preparation method and construction of the nano-liquid soil solidifier in this embodiment are the same as those in Example 1.

[0099] Example 18

[0100] This embodiment provides a nano-liquid soil solidifying agent, comprising the following components:

[0101] Raw materials: 40 kg water, 15 kg stabilizer (isopropyl alcohol: ethylene glycol = 2:1), 20 kg modifier, 1 kg nano-silica (particle size 100 nm), 13 kg active agent, 1 kg ion stabilizer (sodium chloride), 11 kg dispersant, 2 kg accelerator (triethanolamine oleate: triisopropanolamine = 1:1).

[0102] The preparation method and construction of the nano-liquid soil solidifier in this embodiment are the same as those in Example 1.

[0103] Example 19

[0104] This embodiment provides a nano-liquid soil solidifying agent, comprising the following components:

[0105] Raw materials: 56 kg water, 4 kg stabilizer (ethanol: propylene glycol = 2:1), 10 kg modifier, 1 kg nano-aluminum oxide (particle size 100 nm), 13 kg active agent, 3 kg ion stabilizer (sodium chloride: potassium chloride = 1:1), 11 kg dispersant, 2 kg promoter (triethanolamine oleate).

[0106] The preparation method and construction of the nano-liquid soil solidifier in this embodiment are the same as those in Example 1.

[0107] Example 20

[0108] This embodiment provides a nano-liquid soil solidifying agent, comprising the following components:

[0109] Raw materials: 50 kg water, 10 kg stabilizer (ethanol: ethylene glycol = 3:1), 10 kg modifier, 2 kg nano-aluminum oxide (particle size 20 nm), 20 kg active agent, 1 kg ion stabilizer (sodium chloride), 2 kg dispersant, 5 kg accelerator (triethanolamine oleate: triethanolamine = 2:1).

[0110] The preparation method and construction of the nano-liquid soil solidifier in this embodiment are the same as those in Example 1.

[0111] Example 21

[0112] This embodiment provides a nano-liquid soil solidifying agent, comprising the following components:

[0113] Raw materials: 46 kg water, 15 kg stabilizer (isopropyl alcohol), 6 kg modifier, 1 kg nano-alumina (particle size of 20 nm and 100 nm mixed in equal proportions), 10 kg active agent, 1 kg ion stabilizer (sodium sulfate: potassium chloride = 1:1), 7 kg dispersant, 15 kg accelerator (triethanolamine oleate: triisopropanolamine = 1:1).

[0114] The preparation method and construction of the nano-liquid soil solidifier in this embodiment are the same as those in Example 1.

[0115] Example 22

[0116] This embodiment provides a nano-liquid soil solidifying agent, comprising the following components:

[0117] Raw materials: 40 kg water, 20 kg stabilizer (ethanol), 6 kg modifier, 1 kg nano-aluminum oxide (particle size 100 nm), 20 kg active agent, 1 kg ion stabilizer (sodium chloride: potassium chloride = 1:1), 7 kg dispersant, 5 kg accelerator (triethanolamine oleate: diethanolamine = 3:1).

[0118] The preparation method and construction of the nano-liquid soil solidifier in this embodiment are the same as those in Example 1.

[0119] Example 23

[0120] This embodiment provides a nano-liquid soil solidifying agent, comprising the following components:

[0121] Raw materials: 40 kg of water, 4 kg of stabilizer (isopropyl alcohol: ethylene glycol = 2:1), 20 kg of modifier, 1 kg of nano-silicon dioxide (particle size of 10 nm and 100 nm mixed in equal ratio), 13 kg of active agent, 2 kg of ion stabilizer (sodium chloride), 11 kg of dispersing agent, 9 kg of promoter (oleic acid triethanolamine).

[0122] The preparation method and construction of the nano-liquid soil stabilizer of the present embodiment are the same as those of Example 1.

[0123] Example 24

[0124] The present embodiment provides a nano-liquid soil stabilizer which is the same as Example 1, and the only difference is that when the soil stabilizer is applied to the construction of the base road engineering, the mass of the soil stabilizer remains unchanged, and the ratio of the soil stabilizer to dry soil is 1:1000.

[0125] Example 25

[0126] The present embodiment provides a nano-liquid soil stabilizer which is the same as Example 1, and the only difference is that when the soil stabilizer is applied to the construction of the base road engineering, 5% of quicklime and 5% of silicate cement are added to the soil material, and a road mixer is used for mixing; among them, the quicklime needs to be added in advance, and the material needs to be stewed for 5 days, and the ratio of the soil stabilizer to dry soil is 1:600.

[0127] Example 26

[0128] The present embodiment provides a nano-liquid soil stabilizer which is the same as Example 1, and the only difference is that when the soil stabilizer is applied to the construction of the base road engineering, 3% of quicklime and 3% of silicate cement are added to the soil material, and a road mixer is used for mixing; among them, the quicklime needs to be added in advance, and the material needs to be stewed for 5 days, and the ratio of the soil stabilizer to dry soil is 1:600.

[0129] Example 27

[0130] The present embodiment provides a nano-liquid soil stabilizer which is the same as Example 1, and the only difference is that when the soil stabilizer is applied to the construction of the base road engineering, 3% of quicklime and 8% of silicate cement are added to the soil material, and a road mixer is used for mixing; among them, the quicklime needs to be added in advance, and the material needs to be stewed for 5 days, and the ratio of the soil stabilizer to dry soil is 1:600.

[0131] Comparative Example 12

[0132] The preparation method is the same as Example 1, and the only difference is that when the soil stabilizer is applied to the construction of the base road engineering, the mass of the soil stabilizer remains unchanged, and the ratio of the soil stabilizer to dry soil is 1:6000.

[0133] Test Example 1 Performance Test

[0134] 1. Performance testing methods

[0135] In this test example, performance tests were conducted on Examples 1 to 27 and Comparative Examples 1 to 12, and soil without curing agent was used as a blank control (wherein the amounts of quicklime and cement added were the same as in Example 1).

[0136] (1) Preparation, curing and determination of unconfined compressive strength of solidified soil test blocks:

[0137] Standard specimens were made in accordance with JTG 3441-2024 "Test Procedures for Stabilized Materials with Inorganic Binders for Highway Engineering" and cured under the specified standard temperature and humidity environment (standard curing temperature 20℃±2℃, relative humidity 95%). The unconfined compressive strength values ​​after 7-day curing, 6+1 (6-day curing, 1-day immersion), and 4-hour post-forming were measured using a pavement strength tester.

[0138] The calculation formula of the unconfined compressive strength of the specimen is as follows:

[0139] (Formula 1)

[0140] Where R c ——unconfined compressive strength of the specimen (MPa);

[0141] P——maximum pressure when the specimen is destroyed (N);

[0142] A——cross-sectional area of ​​the specimen (mm 2 ).

[0143] (2) Moisture content of stabilized soil: The moisture content of the same test piece of stabilized soil was measured before and after curing. Specifically, the freshly pressed stabilized soil sample was weighed together with an aluminum box (mass m0) as m1, placed in an oven at 105°C for 24 hours to a constant weight, and then cooled and weighed together with the aluminum box as m2. The moisture content calculation formula is as follows:

[0144] (Formula 2)

[0145] Where, W is the water absorption rate of the sample (%);

[0146] m1——mass of test block before curing (g);

[0147] m2——mass of the test block after curing (g).

[0148] (4) Coefficient of influence of setting time

[0149] The ratio of the unconfined compressive strength of the specimen formed after 4 hours to that of the specimen formed immediately; according to the standard "Soil Solidification Admixtures" (CJ / T 486-2015), the setting time influence coefficient ratio is ≥100%.

[0150] (5) Coefficient ratio of setting time

[0151] The ratio of the setting time influence coefficients of the test specimen to that of the reference specimen.

[0152] (6) Water stability coefficient

[0153] The ratio of the unconfined compressive strength of the specimens at the standard curing age (6+1 days, soaking in water on the last day) to the unconfined compressive strength of the specimens of the same age without soaking in water is used.

[0154] (7) Water stability coefficient ratio

[0155] The ratio of the water stability coefficient of the test specimen to that of the reference specimen; according to the standard "Soil Solidification Admixtures" (CJ / T 486-2015), the setting time influence coefficient ratio is ≥100% and the water stability coefficient ratio is ≥105%.

[0156] (8) Scanning electron microscope microscopic test

[0157] The microstructures of Example 1, Comparative Example 1 and the blank control were tested using a scanning electron microscope.

[0158] 2. Performance test results

[0159] Tables 1-5 show the effects of nanoparticles and their particle size. The blank control exhibited an unconfined compressive strength of 2.90 MPa at 7 days, 2.13 MPa at 6+1 days, and 2.07 MPa after 4 hours of molding. The setting time effect coefficient was 0.972, and the water stability coefficient was 0.734. Comparisons in Tables 1-4 indicate that the soil stabilizers prepared in Examples 1-23 exhibited moderate pH values, ranging between weakly acidic and weakly alkaline. After being incorporated into soil with lime and Portland cement, the resulting stabilized soils exhibited high compressive strength at the same compaction level. The measured setting time effect coefficient ratio and water stability coefficient ratio met the requirements specified in the "Soil Stabilizing Admixtures" (CJ / T 486-2015): setting time effect coefficient ratio ≥ 100% and water stability coefficient ratio ≥ 105%. The corresponding stabilized soil moisture content was kept below 18%.

[0160] (1) Nanoparticles and their particle size effects

[0161] As shown in Table 1, it can be seen from Example 1 and Comparative Example 1 that the soil solidifier incorporating nanoparticles (such as nano-SiO2) can significantly improve the compressive strength of the solidified soil, and the 7-day unconfined compressive strength is increased by 30.3%.

[0162] As can be seen from Examples 1, 2, and 5, both nano-SiO2 and nano-Al2O3 can improve the strength of solidified soil to varying degrees. Both can promote the hydration of cement in solidified soil and, as nanoparticles, fill the pores of the solidified soil and the cementitious material after hydration. However, comparing the compressive strength of the solidified soil, nano-SiO2 clearly outperforms nano-Al2O3.

[0163] It can be seen from Example 1, Example 3, Example 4 and Comparative Example 3 that the nano-SiO2 content has a certain influence on the strength of the solidified soil. Nano-SiO2 can effectively promote the hydration of cement, prompting the generation of the hydration product CSH gel, and also plays the role of nano-particle physical filling, which is beneficial to the improvement of the strength of the solidified soil. Within a certain range, the more nano-SiO2 content, the higher the solidified soil strength. However, as the amount of nano-SiO2 added increases, beyond a certain range value, the nano-particles are difficult to disperse and easily cause agglomeration, and the corresponding solidified soil instead decreases, and the water stability coefficient of the solidified soil obviously decreases.

[0164] As can be seen from Examples 1, 6, 7, and Comparative Example 2, SiO2 with a particle size within a certain range can fill the pores of the solidified soil and cement hydration gelling material, thereby increasing the compactness of the solidified soil and improving the strength of the solidified soil. The data show that the mechanical strength of the solidified soil with 20 nm SiO2 is superior to that of the solidified soil with 10 nm SiO2 and 100 nm SiO2. When the particle size range is exceeded, the mechanical strength of the solidified soil decreases significantly. For example, the 7-day unconfined compressive strength of the solidified soil with 500 nm SiO2 decreases by 18.3% compared to the solidified soil with 20 nm SiO2.

[0165] Table 1 Effects of nanoparticles and their particle sizes on test indicators in Examples 1 to 7 and Comparative Examples 1 to 3

[0166] Table 2 Effects of multiple parameters on test indicators in Examples 15 to 23

[0167] (2) Influence of modifiers, active agents and dispersants

[0168] The modifier acts on the surface of nano-SiO2 particles through hydrogen bonds, making nano-SiO2 easy to disperse during the incorporation process, which helps to improve the strength of the solidified soil. As shown in Tables 1 and 3 above, it can be seen from Example 1, Example 8 and Comparative Example 4 that the 7-day unconfined compressive strength of the solidified soil incorporating 10% modifier is significantly improved compared to Comparative Example 4, with an improvement of 31.6%. In addition, the modifier acts as a surfactant to reduce surface tension, which helps to improve the water resistance of the solidified soil. As the amount of modifier incorporated increases, the corresponding solidified soil water stability coefficient shows a trend of first increasing and then decreasing. When 10% of the modifier is incorporated, the solidified soil water stability coefficient reaches an optimal value, i.e. 0.835. The modifier also plays a role in regulating the acidity and alkalinity of the soil solidifier. Its sulfonic acid component neutralizes the alkalinity in the original solidifying agent well.

[0169] The ions or polar groups in the active agent can form chemical bonds with the metal cations on the surface of the soil particles, promoting flocculation on the surface of the soil particles, which is beneficial to increase the strength of the solidified soil. In addition, the hydrophobic chains in the active agent are easily adsorbed on the outer surface of the soil particles, improving the water-absorbing properties of the soil particles. It can be seen from Example 1, Example 9, Comparative Example 5 and Comparative Example 6 that there is an optimal value for the amount of active agent added. The 7-day unconfined compressive strength of the solidified soil with 13% active agent added is 13.2% higher than that of the solidified soil without active agent added; its water stability coefficient is increased by 39.4%.

[0170] Dispersants in soil solidifiers also play a role in reducing the surface tension of the solution and adsorbing soil particles. As shown in Examples 1 and 10, Comparative Examples 7, 5, and 6, adding a certain amount of dispersant significantly improves the water resistance of the solidified soil, increasing the water stability coefficient of the corresponding solidified soil, with the water stability coefficient ratio exceeding 105%. However, there is an optimal dispersant dosage, and the water resistance of the corresponding solidified soil is optimal when the dispersant dosage is 9%.

[0171] Table 3 Effects of modifiers, active agents and dispersants on test indicators in Examples 8 to 10 and Comparative Examples 5 to 7

[0172] (3) Effects of accelerators and stabilizers

[0173] The amine structure in the accelerator can form complexes with metal ions in soil, cement and other minerals, accelerating the release of silica and alumina, thereby improving the comprehensive mechanical properties of the solidified soil.

[0174] Examples 1, 11, 12, and Comparative Examples 8 and 9 demonstrate that, within a certain range, the higher the accelerator ratio, the higher the corresponding solidified soil strength. When the accelerator ratio exceeds this range, the soil solidifier exhibits strong alkalinity, easily causing soil alkalization. In this case, the solidified soil setting time influence coefficient is less than 100%, which is not conducive to construction operations.

[0175] The function of stabilizers is to regulate the stretchability of organic molecular chains, making them more susceptible to adsorption of soil particles and forming a hydrophobic layer on the soil surface, thereby improving the water resistance of the stabilized soil. Examples 1, 13, 14, Comparative Examples 10, and 11 demonstrate that, within a certain range, the addition of a certain amount of stabilizer can improve the water resistance of the stabilized soil, resulting in a water-stability coefficient ratio exceeding 105%. However, excessive amounts of stabilizer, exceeding this range, further restrict the stretchability of the organic molecular chains, resulting in a significant decrease in the water-stability coefficient ratio, below the standard value (105%).

[0176] Table 4 Effects of modifiers, active agents and dispersants on test indicators in Examples 11 to 14 and Comparative Examples 8 to 11

[0177] (4) Influence of construction technology

[0178] As shown in Tables 1 and 5, Example 1 and Blank Example 1 (cement-stabilized soil without a solidifying agent), soil solidifying agents contribute to and improve the mechanical properties and water resistance of the solidified soil. Examples 1, 24, and Comparative Example 12 demonstrate that soil solidifying agents contribute to and improve the properties of the solidified soil, which is related to the ratio of the two (soil solidifying agent to dry soil). When the solidifying agent to dry soil ratio is too low (outside the range), the compressive strength is almost the same as that of the blank sample (cement-stabilized soil). Comparing Examples 1 and 25, lime improves the strength of the solidified soil due to ion exchange with soil particles and volcanic ash reactions. However, increasing the lime content actually decreases the strength of the solidified soil. Comparing Examples 1, 26, and 27, it is found that the 7-day unconfined compressive strength of the solidified soil increases with increasing cement content. When the cement content reaches 5%, the strength reaches 3.88 MPa. However, further increasing the cement content does not significantly change the strength value. Therefore, incorporating a high proportion of cement into solidified soil has little economic benefit.

[0179] Table 5 Effect of construction technology of Examples 24 to 27 and Comparative Example 12 on test indicators

[0180] (5) Observe the shape, pores, hydration products, etc. of the solidified soil from the perspective of micromorphology to further explain the mechanical properties; Figures 1 to 3They are SEM images of Example 1, Comparative Example 1 and blank cement-cured soil specimens respectively.

[0181] By comparison Figures 1-3 It can be seen that the blank cement-stabilized soil mainly contains flat aggregates and flaky particles, most of which are loose and have large pores. Therefore, the corresponding compressive strength is relatively low.

[0182] Comparative Example 1 shows that the addition of a SiO2-free soil stabilizer to the stabilized soil increases the amount of cementation products (e.g., CSH) and forms irregular, blocky aggregates. Small amounts of needle-shaped ettringite are distributed within the aggregates. However, the soil itself exhibits significant pores, resulting in moderate compressive strength.

[0183] In Example 1, after treatment with the nano-liquid soil solidifier, the hydrated cementing material in the solidified soil increased significantly. The soil particles entrained by the cementing product formed large blocks, and the boundaries between the particles became more blurred. The images also show that SiO2 nanoparticles fill the pores between the soil particles and the cement, and that a large amount of cement hydration products, such as amorphous CSH cementitious material and needle-shaped ettringite (AFt), are interspersed in the solidified soil. In summary, the addition of the nano-liquid soil solidifier significantly increases the cementing product of the solidified soil, greatly reduces the pores between the particles, and significantly improves the compactness. Therefore, the macroscopic manifestation is improved mechanical properties.

[0184] The above performance test results show that the nano-liquid soil solidifier of the present invention has a moderate pH value, and the solidified soil prepared with quicklime, cement and soil has excellent performance parameters such as compressive strength, water stability coefficient, setting time influence coefficient and moisture content.

[0185] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A nano liquid soil solidifier, characterized in that: The following raw materials are included in parts by weight: 6-20 parts of modifier; 4-20 parts of stabilizer; 0.5-2 parts of nanoparticles; 10-20 parts of active agent; 1-2 parts of ionic stabilizer; 2-11 parts of dispersant; 2-15 parts of accelerator; The stabilizer comprises one or more components of isopropyl alcohol, ethanol, propylene glycol and ethylene glycol; The nanoparticles comprise silicon dioxide or aluminum oxide, and the nanoparticle size ranges from 10 to 100 nm; The ion stabilizer is one or more components of sodium chloride, potassium chloride, and sodium sulfate; The accelerator is one or more components of triethanolamine oleate, triethanolamine, isopropanolamine, and diethanolamine.

2. The nano liquid soil solidifier according to claim 1, characterized in that The invention also includes 40 to 60 parts by weight of solvent water.

3. The nano liquid soil solidifying agent according to claim 1, characterized in that: The stabilizers are isopropyl alcohol and propylene glycol, and the ratio of isopropyl alcohol to propylene glycol is 3:

1.

4. The nano liquid soil solidifier according to claim 1, characterized in that: The nanoparticles are silicon dioxide or aluminum oxide, and the particle size of the silicon dioxide and aluminum oxide nanoparticles is 10-100 nm. Preferably, the particle size of the silicon dioxide and aluminum oxide nanoparticles is 10-20 nm.

5. The nano liquid soil solidifier according to claim 1, characterized in that: The ion stabilizers are sodium sulfate and potassium chloride, and the ratio of sodium sulfate to potassium chloride is 1:

1.

6. The nano liquid soil solidifying agent according to claim 1, characterized in that: The accelerators are triethanolamine oleate and triethanolamine; the ratio of triethanolamine oleate to triethanolamine is 2:

1.

7. The nano liquid soil solidifier according to claim 1, characterized in that: The modifier is composed of the following components in mass fraction: 40% Span 85, 50% Span 80 and 10% sulfonic acid; the active agent is composed of the following components in mass fraction: 50% sodium dodecyl diphenyl ether disulfonate, 45% sodium long-chain carboxylate polyoxyethylene sulfonate and 5% sodium fatty acid methyl ester sulfonate; the dispersant is composed of the following components in mass fraction: 55% fatty alcohol polyoxyethylene ether and 45% dodecylphenol polyoxyethylene ether.

8. The method for preparing the nano-liquid soil solidifying agent according to claim 1, characterized in that: The steps include: S1. The nanoparticles and the modifier were dispersed in water at 50~60 ℃ to form a mixture, stirred at a speed of 300~500r / min for 1 hour, and then ultrasonicated in an ultrasonic device with a power of 600W for 30min to obtain a dispersion 1; S2. The active agent and the ionic stabilizer were sequentially added to the dispersion 1 at 50~60°C and stirred at a speed of 300~500r / min for 2~4 hours to obtain a dispersion 2; S3. The dispersant fatty alcohol polyoxyethylene ether was added to the dispersion 2, and after stirring and dissolving, the dispersant dodecylphenol polyoxyethylene ether was added dropwise, wherein the addition rate was 1 to 3 d / s, the stirring speed was 150 to 400r / min, to obtain a dispersion 3; S4. Add the accelerator dropwise to the dispersion 3 at a dropping speed of 1 to 3 d / s and stir at a speed of 200 to 400 r / min for 1 to 2 hours to obtain a nano-liquid soil solidifier.

9. Use of the nano liquid soil solidifier according to claim 1 in solidifying soil.

10. The use according to claim 9, characterized in that: The soil solidifier according to claim 1 is diluted with water and then sprayed on a dry mix containing dry soil, mixed evenly, and rolled until flat; the ratio of the soil solidifier to the dry soil is 1:5000~1:500; the dry mix is ​​prepared by adding 2~8% of quicklime and 3~8% of Portland cement by relative mass to the soil material, and mixing it evenly using a road mixer.

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