A cured soil with increased bending resistance and a method of making the same

Abstract

The application discloses a kind of solidified soil of enhanced bending resistance, raw materials thereof include: soil solidifying agent and soil, the mass ratio of soil solidifying agent and soil is 1-2:10000;The raw materials of soil solidifying agent include by weight parts: zirconium oxychloride 2-6 parts, cerium nitrate hexahydrate 0.1-1 part, reed fiber 5-15 parts, magnesium sulfate whisker 1-3 parts, poly (propylene glycol) -silane-poly (ethylene glycol) 2-8 parts, bisphenol A epoxy resin 15-35 parts, phthalic anhydride 0.1-1 part, ordinary portland cement 30-40 parts, fly ash 25-35 parts, montmorillonite micro powder 2-8 parts, silicon micro powder 1-5 parts, sodium silicate 1-5 parts, polycarboxylic acid polymer 1-2 parts, expanding agent 1-5 parts, sodium hexametaphosphate 1-2 parts, alkyl dimethyl benzyl ammonium chloride ammonium chloride 1-2 parts.The application discloses the above-mentioned method for manufacturing solidified soil of enhanced bending resistance.

Description

Technical Field

[0001] This invention relates to the field of solidified soil technology, and in particular to a solidified soil with enhanced flexural strength and its preparation method. Background Technology

[0002] Soil stabilization is frequently required during construction projects such as buildings, bridges, and roads. Soil stabilization essentially involves using admixtures to physically and / or chemically treat the soil, thereby altering its composition and engineering properties to improve soil strength and compaction.

[0003] Currently, most areas in my country have a large amount of soft soil, which has fine particles, high water content, low permeability, high compressibility, large settlement, and poor drainage consolidation stability. At the same time, the thickness of soft soil can reach about 30-40m. Due to the large differences in mechanical properties, the self-compacting settlement of new road embankments is usually greater than that of old road embankments, resulting in large uneven deformation or settlement at the cross-section of the new and old roadbeds. This excessive differential settlement will damage the service performance of the highway and thus affect its normal operation.

[0004] Currently, deep mixing is the most common method for foundation treatment. This method involves adding cement or other curing agents to the soil in situ and then forcibly mixing it to combine it with the soil and improve its strength. However, this in-situ mixing method is often uneven due to a lack of flow and operating space, as well as mechanical equipment, resulting in lower strength after treatment.

[0005] Currently, the commonly used soil stabilizers in the construction industry are those that improve soil using lime, cement, etc., and these stabilizers are effective in the early stages of a project. However, in long-term soil stabilization projects, it has been gradually recognized that the compressive strength of traditional soil stabilization materials such as lime and cement is insufficient, leading to the need to increase the amount of stabilizer added during construction to compensate for the lack of strength; furthermore, their water resistance is not good enough, and they cannot solidify the foundation soil after prolonged soaking in rainwater.

[0006] Currently, the most effective way to utilize these natural soils and improve their properties to meet the construction requirements for compressive strength and water resistance, while also reducing the construction cycle, realizing waste utilization, and improving the convenience of construction, has become an urgent task for the industry. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by proposing a solidified soil with enhanced flexural strength and a method for its preparation.

[0008] A type of stabilized soil with enhanced bending resistance, comprising: soil stabilizer and soil, wherein the mass ratio of soil stabilizer to soil is 1-2:10000; the raw materials of the soil stabilizer, by weight, include: 2-6 parts zirconium oxychloride octahydrate, 0.1-1 parts cerium nitrate hexahydrate, 5-15 parts reed fiber, 1-3 parts magnesium sulfate whiskers, 2-8 parts poly(propylene glycol)-silane-poly(ethylene glycol), 15-35 parts bisphenol A epoxy resin, 0.1-1 parts phthalic anhydride, 30-40 parts ordinary silicate cement, 25-35 parts fly ash, 2-8 parts montmorillonite powder, 1-5 parts silica powder, 1-5 parts sodium silicate, 1-2 parts polycarboxylate polymer, 1-5 parts expansion agent, 1-2 parts sodium hexametaphosphate, and 1-2 parts alkyl dimethyl benzyl ammonium chloride.

[0009] Preferably, the cattail fiber is carbonized cattail fiber.

[0010] Preferably, carbonized cattail fiber is prepared by the following specific steps: adding cattail fiber to an aqueous solution of sodium hypochlorite, adjusting the pH of the system to 3-4, stirring for 1-2 hours, heating to 70-90℃ and stirring for 10-30 minutes, filtering, washing, drying, and calcining at 900-1000℃ under a nitrogen atmosphere for 10-30 minutes to obtain carbonized cattail fiber.

[0011] Preferably, the sodium hypochlorite aqueous solution has a mass fraction of 0.2-1%, and the mass ratio of reed fiber to sodium hypochlorite aqueous solution is 5-15:30-50.

[0012] Preferably, the diameter of the carbonized cattail fiber is 1-10 μm.

[0013] Preferably, the silicon micro powder is made by grinding quartz sand, wherein the mass percentage of particles with a particle size of less than 1 μm is greater than 90%, and the SiO2 content is greater than 93.1%.

[0014] Preferably, the specific surface area of ​​montmorillonite powder is ≥525m². 2 / kg, SiO2 content > 51.4%, Al2O3 content > 4.8%, MgO content > 26.2%.

[0015] The above-mentioned method for preparing solidified soil with enhanced flexural strength includes the following steps:

[0016] S1. Add zirconium oxychloride octahydrate and cerium nitrate hexahydrate to an ethanol aqueous solution and stir evenly. Add reed fiber and ultrasonically treat. Then cool to -35 to -45℃, freeze dry for 10-20h, sinter at 900-1300℃ in an oxygen atmosphere for 20-40min, and cool with the furnace to obtain pre-made bending-resistant fiber.

[0017] S2. Magnesium sulfate whiskers are continuously stirred at 62-68℃ for 1-2 hours. While stirring, poly(propylene glycol)-silane-poly(ethylene glycol) is added dropwise. After the addition is complete, stirring is continued for 5-15 minutes. The mixture is then cooled to room temperature, centrifuged, and dried. Bisphenol A epoxy resin and pre-formed anti-bending fibers are added. The mixture is then degassed and stirred at room temperature for 1-2 hours to obtain composite bisphenol A epoxy resin.

[0018] S3. Mix ordinary silicate cement, fly ash, montmorillonite powder, silica powder, composite bisphenol A epoxy resin, sodium silicate, polycarboxylic acid polymer, and water evenly. Add expansion agent, sodium hexametaphosphate, and alkyl dimethyl benzyl ammonium chloride and stir for 10-30 minutes. Cure at 30-35℃ for 5-10 hours to obtain soil stabilizer. Mix the soil stabilizer with soil and solidify.

[0019] Preferably, in S1, the ultrasonic treatment time is 5-15 min and the ultrasonic frequency is 5-12 kHz.

[0020] Preferably, during the cooling and freezing process of S1, the cooling rate is 3-7℃ / min.

[0021] Freeze-drying is performed by using a freeze dryer. The cooling element of the freeze dryer is located on its bottom side. The freeze dryer first cools the bottom of the material on it, causing ice crystals to grow along the direction of the temperature gradient.

[0022] The technical effects of this invention are as follows:

[0023] This application treats reed fibers with sodium hypochlorite to promote the full release of the fiber structure, followed by high-temperature carbonization, which causes the fiber structure to interweave to form a network structure, while the fiber interior is hollow. Using reed fibers as a template, this application employs zirconium oxychloride sintering, so that the resulting zirconium oxide fibers not only inherit the hollow structure, but also, during the directional freezing process, ice crystals advance from the bottom of the material upwards, compressing the zirconium oxide molecules. The ice crystals between the zirconium oxide molecules promote the formation of an ordered porous structure on the hollow zirconium oxide fiber tube, while cerium doping can effectively stabilize the tetragonal phase structure of zirconium oxide.

[0024] In S2, the hydrophilic end of poly(propylene glycol)-silane-poly(ethylene glycol) combines with magnesium sulfate whiskers, while the hydrophobic end combines with bisphenol A epoxy resin, effectively promoting better dispersibility of magnesium sulfate whiskers. Then, when compounded with pre-fabricated anti-bending fibers, it not only allows the bisphenol A epoxy resin macromolecules to fully enter the hollow structure of the pre-fabricated anti-bending fibers, but also greatly improves the efficiency and service life of fluid treatment of soil, without affecting the fluidity of the grouting process, thus greatly improving grouting efficiency.

[0025] After soil solidification, the bisphenol A epoxy resin and poly(propylene glycol)-silane-poly(ethylene glycol) compound promote rapid solidification of the solidified soil and its formation into a whole. The amphiphilic nature of the soil solidifier increases the attraction between particles, which not only reduces the overall thickness of the soil particles and the solidified soil, but also attracts bisphenol A epoxy resin to adhere to the surface of the newly formed crystals on the surface of the aggregated soil particles, weakening the surface charge of the soil particles. The soil and solidifier components move closer together, making the solidified soil denser and with higher mechanical strength. The pre-fabricated anti-bending fibers are fully solidified in the solidified soil structure under the action of bisphenol A epoxy resin, which can effectively reduce the internal strain of the solidified soil, prevent cracking, and improve the overall strength of the solidified soil.

[0026] Compared to soil without prefabricated flexural fibers, this invention significantly enhances the flexural stability and water resistance of the stabilized soil, particularly its resistance to deformation in acidic solutions. This invention provides excellent soil stabilization, enabling in-situ reinforcement of soft soil foundations and possessing high application value for soft soil foundation widening projects. Attached Figure Description

[0027] Figure 1 The image shows a comparison of the unconfined compressive strength of soil after 7 days of solidification using the soil stabilizers obtained in Examples 3, 6, and the comparative example.

[0028] Figure 2 This is a comparison chart of the deformation modulus of the solidified soils obtained in Examples 3, 6, and the comparative example under different acidic conditions. Detailed Implementation

[0029] The present invention will be further explained below with reference to specific embodiments.

[0030] Example 1

[0031] A type of stabilized soil with enhanced bending resistance, the raw materials of which include: soil stabilizer and soil, wherein the mass ratio of soil stabilizer to soil is 1:10000.

[0032] The raw materials for the soil stabilizer include: 2 kg of zirconium oxychloride octahydrate, 0.1 kg of cerium nitrate hexahydrate, 5 kg of reed fiber, 1 kg of magnesium sulfate whiskers, 2 kg of poly(propylene glycol)-silane-poly(ethylene glycol), 15 kg of bisphenol A epoxy resin, 0.1 kg of phthalic anhydride, 30 kg of ordinary silicate cement, 25 kg of fly ash, 2 kg of montmorillonite powder, 1 kg of silica powder, 1 kg of sodium silicate, 1 kg of polycarboxylic acid polymer, 1 kg of expansion agent, 1 kg of sodium hexametaphosphate, and 1 kg of alkyl dimethyl benzyl ammonium chloride.

[0033] The above-mentioned method for preparing solidified soil with enhanced flexural strength includes the following steps:

[0034] S1. Add zirconium oxychloride octahydrate and cerium nitrate hexahydrate to 20 kg of 40% ethanol aqueous solution and stir evenly. Add reed fiber and sonicate for 5 min at a frequency of 5 kHz. Then send it to a freeze dryer and cool it from room temperature to -35℃ at a rate of 3℃ / min. Freeze for 10 h and then add it to a high-temperature muffle furnace. Sinter at 900℃ in an oxygen atmosphere for 20 min and cool with the furnace to obtain pre-made bending-resistant fiber.

[0035] S2. Add magnesium sulfate whiskers to a mixer and stir at 62℃ for 1 hour. While stirring, add poly(propylene glycol)-silane-poly(ethylene glycol) dropwise. Continue stirring for 5 minutes after the addition is complete. Cool to room temperature, centrifuge, dry, add bisphenol A epoxy resin and pre-formed anti-bending fiber, reduce pressure and evacuate, add phthalic anhydride curing agent and mix evenly. Degas and stir at room temperature for 1 hour to obtain composite bisphenol A epoxy resin.

[0036] S3. Mix ordinary silicate cement, fly ash, montmorillonite powder, silica powder, composite bisphenol A epoxy resin, sodium silicate, polycarboxylic acid polymer, and water evenly. Add expansion agent, sodium hexametaphosphate, and alkyl dimethyl benzyl ammonium chloride. Stir for 10 minutes and place in a 30℃ curing chamber for 5 hours to obtain a soil stabilizer. Mix the soil stabilizer with soil and solidify.

[0037] Example 2

[0038] A type of solidified soil with enhanced bending resistance, the raw materials of which include: soil stabilizer and soil, wherein the mass ratio of soil stabilizer to soil is 2:10000.

[0039] The raw materials for the soil stabilizer include: 6 kg of zirconium oxychloride octahydrate, 1 kg of cerium nitrate hexahydrate, 15 kg of reed fiber, 3 kg of magnesium sulfate whiskers, 8 kg of poly(propylene glycol)-silane-poly(ethylene glycol), 35 kg of bisphenol A epoxy resin, 1 kg of phthalic anhydride, 40 kg of ordinary silicate cement, 35 kg of fly ash, 8 kg of montmorillonite powder, 5 kg of silica powder, 5 kg of sodium silicate, 2 kg of polycarboxylic acid polymer, 5 kg of expansion agent, 2 kg of sodium hexametaphosphate, and 2 kg of alkyl dimethyl benzyl ammonium chloride.

[0040] The above-mentioned method for preparing solidified soil with enhanced flexural strength includes the following steps:

[0041] S1. Add zirconium oxychloride octahydrate and cerium nitrate hexahydrate to 40 kg of 60% ethanol aqueous solution and stir evenly. Add reed fiber and sonicate for 15 min at an ultrasonic frequency of 12 kHz. Then send it to a freeze dryer and cool it from room temperature to -45℃ at a rate of 7℃ / min for 20 h. Add it to a high-temperature muffle furnace and sinter at 1300℃ in an oxygen atmosphere for 40 min. Cool it with the furnace to obtain pre-made bending-resistant fiber.

[0042] S2. Add magnesium sulfate whiskers to a mixer and stir at 68℃ for 2 hours. While stirring, add poly(propylene glycol)-silane-poly(ethylene glycol) dropwise. Continue stirring for 15 minutes after the addition is complete. Cool to room temperature, centrifuge, dry, add bisphenol A epoxy resin and pre-formed anti-bending fiber, reduce pressure and evacuate, add phthalic anhydride curing agent and mix evenly. Degas and stir at room temperature for 2 hours to obtain composite bisphenol A epoxy resin.

[0043] S3. Mix ordinary silicate cement, fly ash, montmorillonite powder, silica powder, composite bisphenol A epoxy resin, sodium silicate, polycarboxylic acid polymer, and water evenly. Add expansion agent, sodium hexametaphosphate, and alkyl dimethyl benzyl ammonium chloride. Stir for 30 minutes and place in a 35℃ curing chamber for 10 hours to obtain a soil stabilizer. Mix the soil stabilizer with soil and solidify.

[0044] Example 3

[0045] A type of solidified soil with enhanced bending resistance, the raw materials of which include: soil stabilizer and soil, wherein the mass ratio of soil stabilizer to soil is 1.6:10000.

[0046] The raw materials for the soil stabilizer include: 4 kg of zirconium oxychloride octahydrate, 0.5 kg of cerium nitrate hexahydrate, 10 kg of reed fiber, 5 kg of magnesium sulfate whiskers, 5 kg of poly(propylene glycol)-silane-poly(ethylene glycol), 25 kg of bisphenol A epoxy resin, 0.5 kg of phthalic anhydride, 35 kg of ordinary silicate cement, 30 kg of fly ash, 5 kg of montmorillonite powder, 3 kg of silica powder, 3 kg of sodium silicate, 1.5 kg of polycarboxylic acid polymer, 3 kg of expansion agent, 1.5 kg of sodium hexametaphosphate, and 1.5 kg of alkyl dimethyl benzyl ammonium chloride.

[0047] The above-mentioned method for preparing solidified soil with enhanced flexural strength includes the following steps:

[0048] S1. Add zirconium oxychloride octahydrate and cerium nitrate hexahydrate to 30 kg of 50% ethanol aqueous solution and stir evenly. Add reed fiber and sonicate for 10 min at an ultrasonic frequency of 9 kHz. Then send it to a freeze dryer and cool it from room temperature to -40℃ at a rate of 5℃ / min. Freeze for 15 h and then add it to a high-temperature muffle furnace. Sinter at 1100℃ in an oxygen atmosphere for 30 min and cool with the furnace to obtain pre-made bending-resistant fiber.

[0049] S2. Add magnesium sulfate whiskers to a mixer and stir at 65℃ for 90 minutes. While stirring, add poly(propylene glycol)-silane-poly(ethylene glycol) dropwise. Continue stirring for 10 minutes after the addition is complete. Cool to room temperature, centrifuge, and dry. Add bisphenol A epoxy resin and pre-formed anti-bending fiber. Vacuum under reduced pressure and add phthalic anhydride curing agent. Mix evenly, degas, and stir at room temperature for 90 minutes to obtain composite bisphenol A epoxy resin.

[0050] S3. Mix ordinary silicate cement, fly ash, montmorillonite powder, silica powder, composite bisphenol A epoxy resin, sodium silicate, polycarboxylic acid polymer, and water evenly. Add expansion agent, sodium hexametaphosphate, and alkyl dimethyl benzyl ammonium chloride. Stir for 20 minutes and place in a 33℃ curing chamber for 7 hours to obtain a soil stabilizer. Mix the soil stabilizer with soil and solidify.

[0051] Example 4

[0052] A type of solidified soil with enhanced bending resistance, the raw materials of which include: soil stabilizer and soil, wherein the mass ratio of soil stabilizer to soil is 1.2:10000.

[0053] The raw materials for the soil stabilizer include: 5 kg of zirconium oxychloride octahydrate, 0.2 kg of cerium nitrate hexahydrate, 13 kg of carbonized reed fiber, 1.5 kg of magnesium sulfate whiskers, 6 kg of poly(propylene glycol)-silane-poly(ethylene glycol), 20 kg of bisphenol A epoxy resin, 0.7 kg of phthalic anhydride, 33 kg of ordinary silicate cement, 32 kg of fly ash, 4 kg of montmorillonite powder, 4 kg of silica powder, 2 kg of sodium silicate, 1.7 kg of polycarboxylic acid polymer, 2 kg of expansion agent, 1.7 kg of sodium hexametaphosphate, and 1.2 kg of alkyl dimethyl benzyl ammonium chloride.

[0054] Carbonized cattail fiber is prepared by the following specific steps: 15 kg of cattail fiber is added to 30 kg of 1% sodium hypochlorite aqueous solution, the pH of the system is adjusted to 3-4 with acetic acid, stirred at 500 r / min for 2 h at room temperature, the temperature is raised to 70℃ and stirred for 30 min, filtered, washed, dried in an oven at 70℃ to constant weight, and calcined at 900℃ for 30 min under nitrogen atmosphere, with the temperature raised from room temperature to 4℃ / min, to obtain carbonized cattail fiber with a diameter of 1-10 μm.

[0055] The above-mentioned method for preparing solidified soil with enhanced flexural strength includes the following steps:

[0056] S1. Add zirconium oxychloride octahydrate and cerium nitrate hexahydrate to 25 kg of 55% ethanol aqueous solution and stir evenly. Add carbonized reed fiber and sonicate for 8 min at an ultrasonic frequency of 10 kHz. Then send it to a freeze dryer and cool it from room temperature to -42℃ at a rate of 4℃ / min. Freeze for 12 h and then add it to a high-temperature muffle furnace. Sinter at 1200℃ in an oxygen atmosphere for 25 min and cool with the furnace to obtain pre-made bending-resistant fiber.

[0057] S2. Add magnesium sulfate whiskers to a mixer and stir at 66℃ for 70 min. While stirring, add poly(propylene glycol)-silane-poly(ethylene glycol) dropwise. Continue stirring for 12 min after the addition is complete. Cool to room temperature, centrifuge, dry, add bisphenol A epoxy resin and pre-formed anti-bending fiber, reduce pressure and evacuate, add phthalic anhydride curing agent and mix evenly. Degas and stir at room temperature for 80 min to obtain composite bisphenol A epoxy resin.

[0058] S3. Mix ordinary silicate cement, fly ash, montmorillonite powder, silica powder, composite bisphenol A epoxy resin, sodium silicate, polycarboxylic acid polymer, and water evenly. Add expansion agent, sodium hexametaphosphate, and alkyl dimethyl benzyl ammonium chloride. Stir for 25 minutes and place in a 32℃ curing chamber for 8 hours to obtain a soil stabilizer. Mix the soil stabilizer with soil and solidify.

[0059] Example 5

[0060] A type of solidified soil with enhanced bending resistance, the raw materials of which include: soil stabilizer and soil, wherein the mass ratio of soil stabilizer to soil is 1.8:10000.

[0061] The raw materials for the soil stabilizer include: 3 kg of zirconium oxychloride octahydrate, 0.8 kg of cerium nitrate hexahydrate, 7 kg of carbonized reed fiber, 2.5 kg of magnesium sulfate whiskers, 4 kg of poly(propylene glycol)-silane-poly(ethylene glycol), 30 kg of bisphenol A epoxy resin, 0.3 kg of phthalic anhydride, 37 kg of ordinary silicate cement, 28 kg of fly ash, 6 kg of montmorillonite powder, 2 kg of silica powder, 4 kg of sodium silicate, 1.3 kg of polycarboxylic acid polymer, 4 kg of expansion agent, 1.3 kg of sodium hexametaphosphate, and 1.8 kg of alkyl dimethyl benzyl ammonium chloride.

[0062] Carbonized cattail fiber is prepared by the following specific steps: 5 kg of cattail fiber is added to 50 kg of 0.2% sodium hypochlorite aqueous solution, the pH of the system is adjusted to 3-4 with acetic acid, stirred at 1000 r / min for 1 h at room temperature, the temperature is raised to 90℃ and stirred for 10 min, filtered, washed, dried in an oven at 80℃ to constant weight, and calcined at 1000℃ for 10 min under nitrogen atmosphere, with the temperature raised from room temperature to 1℃ / min, to obtain carbonized cattail fiber with a diameter of 1-10 μm.

[0063] The above-mentioned method for preparing solidified soil with enhanced flexural strength includes the following steps:

[0064] S1. Add zirconium oxychloride octahydrate and cerium nitrate hexahydrate to 35 kg of 45% ethanol aqueous solution and stir evenly. Add carbonized reed fiber and sonicate for 12 min at an ultrasonic frequency of 8 kHz. Then send it to a freeze dryer and cool it from room temperature to -38℃ at a rate of 6℃ / min. Freeze for 18 h and then add it to a high-temperature muffle furnace. Sinter at 1000℃ in an oxygen atmosphere for 35 min and cool with the furnace to obtain pre-made bending-resistant fiber.

[0065] S2. Add magnesium sulfate whiskers to a mixer and stir at 64℃ for 110 min. While stirring, add poly(propylene glycol)-silane-poly(ethylene glycol) dropwise. Continue stirring for 8 min after the addition is complete. Cool to room temperature, centrifuge, dry, add bisphenol A epoxy resin and pre-formed anti-bending fiber, depressurize and evacuate, add phthalic anhydride curing agent and mix evenly. Degas and stir at room temperature for 100 min to obtain composite bisphenol A epoxy resin.

[0066] S3. Mix ordinary silicate cement, fly ash, montmorillonite powder, silica powder, composite bisphenol A epoxy resin, sodium silicate, polycarboxylic acid polymer, and water evenly. Add expansion agent, sodium hexametaphosphate, and alkyl dimethyl benzyl ammonium chloride. Stir for 15 minutes and place in a 34℃ curing chamber for 6 hours to obtain a soil stabilizer. Mix the soil stabilizer with soil and solidify.

[0067] Example 6

[0068] A type of solidified soil with enhanced bending resistance, the raw materials of which include: soil stabilizer and soil, wherein the mass ratio of soil stabilizer to soil is 1.6:10000.

[0069] The raw materials for the soil stabilizer include: 4 kg of zirconium oxychloride octahydrate, 0.5 kg of cerium nitrate hexahydrate, 10 kg of carbonized reed fiber, 5 kg of magnesium sulfate whiskers, 5 kg of poly(propylene glycol)-silane-poly(ethylene glycol), 25 kg of bisphenol A epoxy resin, 0.5 kg of phthalic anhydride, 35 kg of ordinary silicate cement, 30 kg of fly ash, 5 kg of montmorillonite powder, 3 kg of silica powder, 3 kg of sodium silicate, 1.5 kg of polycarboxylic acid polymer, 3 kg of expansion agent, 1.5 kg of sodium hexametaphosphate, and 1.5 kg of alkyl dimethyl benzyl ammonium chloride.

[0070] Carbonized cattail fiber is prepared by the following specific steps: 10 kg of cattail fiber is added to 40 kg of 0.6% sodium hypochlorite aqueous solution, the pH of the system is adjusted to 3-4 with acetic acid, stirred at 800 r / min for 1.5 h at room temperature, the temperature is raised to 80℃ and stirred for 20 min, filtered, washed, dried in an oven at 75℃ to constant weight, and calcined at 950℃ for 20 min under nitrogen atmosphere, with the temperature raised from room temperature to 2.5℃ / min, to obtain carbonized cattail fiber with a diameter of 1-10 μm.

[0071] The above-mentioned method for preparing solidified soil with enhanced flexural strength includes the following steps:

[0072] S1. Add zirconium oxychloride octahydrate and cerium nitrate hexahydrate to 30 kg of 50% ethanol aqueous solution and stir evenly. Add carbonized reed fiber and sonicate for 10 min at an ultrasonic frequency of 9 kHz. Then send it to a freeze dryer and cool it from room temperature to -40℃ at a rate of 5℃ / min. Freeze for 15 h and then add it to a high-temperature muffle furnace. Sinter at 1100℃ in an oxygen atmosphere for 30 min and cool with the furnace to obtain pre-made bending-resistant fiber.

[0073] S2. Add magnesium sulfate whiskers to a mixer and stir at 65℃ for 90 minutes. While stirring, add poly(propylene glycol)-silane-poly(ethylene glycol) dropwise. Continue stirring for 10 minutes after the addition is complete. Cool to room temperature, centrifuge, and dry. Add bisphenol A epoxy resin and pre-formed anti-bending fiber. Vacuum under reduced pressure and add phthalic anhydride curing agent. Mix evenly, degas, and stir at room temperature for 90 minutes to obtain composite bisphenol A epoxy resin.

[0074] S3. Mix ordinary silicate cement, fly ash, montmorillonite powder, silica powder, composite bisphenol A epoxy resin, sodium silicate, polycarboxylic acid polymer, and water evenly. Add expansion agent, sodium hexametaphosphate, and alkyl dimethyl benzyl ammonium chloride. Stir for 20 minutes and place in a 33℃ curing chamber for 7 hours to obtain a soil stabilizer. Mix the soil stabilizer with soil and solidify.

[0075] Comparative Example

[0076] A type of solidified soil with enhanced bending resistance, the raw materials of which include: soil stabilizer and soil, wherein the mass ratio of soil stabilizer to soil is 1.6:10000.

[0077] The raw materials for the soil stabilizer include: 4 kg of zirconium oxychloride octahydrate, 0.5 kg of cerium nitrate hexahydrate, 10 kg of carbonized reed fiber, 5 kg of magnesium sulfate whiskers, 5 kg of poly(propylene glycol)-silane-poly(ethylene glycol), 25 kg of bisphenol A epoxy resin, 0.5 kg of phthalic anhydride, 35 kg of ordinary silicate cement, 30 kg of fly ash, 5 kg of montmorillonite powder, 3 kg of silica powder, 3 kg of sodium silicate, 1.5 kg of polycarboxylic acid polymer, 3 kg of expansion agent, 1.5 kg of sodium hexametaphosphate, and 1.5 kg of alkyl dimethyl benzyl ammonium chloride.

[0078] Carbonized cattail fiber is prepared by the following specific steps: 10 kg of cattail fiber is added to 40 kg of 0.6% sodium hypochlorite aqueous solution, the pH of the system is adjusted to 3-4 with acetic acid, stirred at 800 r / min for 1.5 h at room temperature, the temperature is raised to 80℃ and stirred for 20 min, filtered, washed, dried in an oven at 75℃ to constant weight, and calcined at 950℃ for 20 min under nitrogen atmosphere, with the temperature raised from room temperature to 2.5℃ / min, to obtain carbonized cattail fiber with a diameter of 1-10 μm.

[0079] The above-mentioned method for preparing solidified soil with enhanced flexural strength includes the following steps:

[0080] S1. Add zirconium oxychloride octahydrate and cerium nitrate hexahydrate to 30 kg of 50% ethanol aqueous solution and stir evenly. Add carbonized reed fiber and ultrasonically treat for 10 min at an ultrasonic frequency of 9 kHz. Dry at 85°C and add to a high-temperature muffle furnace. Sinter at 1100°C in an oxygen atmosphere for 30 min and cool with the furnace to obtain pre-made bending-resistant fiber.

[0081] S2. Add magnesium sulfate whiskers to a mixer and stir at 65℃ for 90 minutes. While stirring, add poly(propylene glycol)-silane-poly(ethylene glycol) dropwise. Continue stirring for 10 minutes after the addition is complete. Cool to room temperature, centrifuge, and dry. Add bisphenol A epoxy resin and pre-formed anti-bending fiber. Vacuum under reduced pressure and add phthalic anhydride curing agent. Mix evenly, degas, and stir at room temperature for 90 minutes to obtain composite bisphenol A epoxy resin.

[0082] S3. Mix ordinary silicate cement, fly ash, montmorillonite powder, silica powder, composite bisphenol A epoxy resin, sodium silicate, polycarboxylic acid polymer, and water evenly. Add expansion agent, sodium hexametaphosphate, and alkyl dimethyl benzyl ammonium chloride. Stir for 20 minutes and place in a 33℃ curing chamber for 7 hours to obtain a soil stabilizer. Mix the soil stabilizer with soil and solidify.

[0083] The soil stabilizers obtained in Examples 3, 6 and the comparative example were mixed evenly with the soil in proportion, placed in plastic bags, and then compacted and cured to obtain stabilized soil with compaction degrees of 96% and 98% respectively. Their 7-day unconfined compressive strength was then measured.

[0084] like Figure 1 As shown, the unconfined compressive strength of the solidified soil with a compaction degree of 98% was significantly higher than that of the solidified soil with a compaction degree of 96%, indicating that the soil stabilizers in each group have a solidification effect on the soil, and the solidification effect is more obvious with the increase of compaction degree.

[0085] The unconfined compressive strength of the solidified soil in Example 6 group with a compaction degree of 98% reached 1.91 MPa, which was better than the other two groups, indicating that the soil solidifier obtained in Example 6 had the best solidification effect.

[0086] The applicant believes that this is because the reed fiber is treated with sodium hypochlorite, which promotes the full release of its fibrous structure. Then, it undergoes high-temperature carbonization, causing the fiber structure to intertwine and form a network structure, while the fiber interior remains hollow. Using reed fiber as a template and employing zirconium oxychloride sintering, the resulting zirconium oxide fiber not only inherits the hollow structure but also, during directional freezing, ice crystals propagate upwards from the bottom of the material, compressing the zirconium oxide molecules. The ice crystals between the zirconium oxide molecules promote the formation of an ordered porous structure on the hollow zirconium oxide fiber tubes. Furthermore, cerium doping effectively stabilizes the tetragonal phase structure of zirconium oxide. The pre-formed flexural fibers, fully cured in the solidified soil structure under the action of bisphenol A epoxy resin, effectively reduce the internal strain of the solidified soil, prevent cracking, exhibit good curing performance, excellent flexural strength, and improve the overall strength of the solidified soil.

[0087] The solidified soils obtained in Examples 3, 6, and the comparative example were placed in a standard curing chamber with constant temperature and humidity. The temperature of the curing chamber was set at 20.5±1℃ and the humidity at 95%. On the 6th day of curing, the soils were removed and completely immersed in a water tank for 24 hours. After curing to the designated age, the performance parameters of each group of samples were tested according to the test methods in JTGE51-2009 "Test Procedures for Inorganic Binder Stabilized Materials for Highway Engineering", as follows:

[0088] Example 3 Example 6 Comparative Example Water stability coefficient, % 91.4 94.6 85.3 The ratio of the influence coefficient of setting time, % 107.5 111.4 102.2 7d compressive resilience modulus, MPa 91.7 94.8 73.5

[0089] The table above shows that the soil stabilizer obtained in this application can improve the structural strength and water stability of the stabilized soil, and has a good stabilization effect. The applicant believes this is because after the soil stabilizer obtained in this application is used to stabilize the soil, the bisphenol A epoxy resin and poly(propylene glycol)-silane-poly(ethylene glycol) compound promote rapid stabilization of the stabilized soil and its formation into a whole. The amphiphilic nature of the soil stabilizer increases the attraction between particles, not only reducing the overall thickness of the soil particles and the stabilized soil, but also attracting bisphenol A epoxy resin to adhere to the surface of the newly formed crystals from the aggregation and coagulation of soil particles, weakening the surface charge of the soil particles. The soil and stabilizer components move closer together, making the stabilized soil denser and with higher mechanical strength. Furthermore, the pre-fabricated anti-bending fibers are fully solidified in the stabilized soil structure under the action of bisphenol A epoxy resin, effectively reducing the internal strain of the stabilized soil, preventing cracking, exhibiting good stabilization performance, excellent flexural performance, and improving the overall strength of the stabilized soil.

[0090] The solidified soils obtained in Examples 3, 6, and the comparative example were placed in a standard curing chamber with constant temperature and humidity, set at 20.5 ± 1℃ and 95% humidity. On the 6th day of curing, they were removed and completely submerged in a water tank for 24 hours. 98% concentrated sulfuric acid was diluted to prepare solutions with pH values ​​of 2, 3.5, and 5 to simulate acid rain environments. Each group of samples was removed from the water and dried to minimize the impact of residual moisture on the solution's pH. They were then completely immersed in the diluted sulfuric acid solution for 72 hours, and the container openings were sealed with plastic wrap to prevent the solution from being exposed to air and causing a decrease in pH, which could affect the accuracy of the test results.

[0091] Since the solidified soil is a nonlinear material, this application uses the secant modulus E. 50 The deformation modulus of solidified soil is expressed by the following formula:

[0092] E 50 =q u ÷2ε'

[0093] Among them, E 50 q is the deformation modulus of the material, with units of MPa; u ε is the unconfined compressive strength of the specimen, in MPa; ε' is the strain corresponding to 50% of the stress peak, in %.

[0094] like Figure 2 As shown, acidic solutions affect the ability of solidified soil to resist deformation, and the solidified soils obtained in Examples 3 and 6 exhibit significantly higher resistance to deformation in acidic solutions than the comparative examples. The applicant believes this is because the pre-fabricated flexural fibers used in this application are fully cured into the solidified soil structure under the action of bisphenol A epoxy resin, which effectively reduces the internal strain of the solidified soil, prevents cracking, improves the overall strength of the solidified soil, and greatly enhances its resistance to deformation in acidic solutions.

[0095] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A cured soil having enhanced resistance to bending, the raw materials of which comprise: The mass ratio of soil stabilizer to soil is 1-2:10000; The raw materials of the soil stabilizer, by weight, include: 2-6 parts zirconium oxychloride octahydrate, 0.1-1 parts cerium nitrate hexahydrate, 5-15 parts reed fiber, 1-3 parts magnesium sulfate whiskers, 2-8 parts poly(propylene glycol)-silane-poly(ethylene glycol), 15-35 parts bisphenol A epoxy resin, 0.1-1 parts phthalic anhydride, 30-40 parts ordinary silicate cement, 25-35 parts fly ash, 2-8 parts montmorillonite powder, 1-5 parts silica powder, 1-5 parts sodium silicate, 1-2 parts polycarboxylate polymer, 1-5 parts expansion agent, 1-2 parts sodium hexametaphosphate, and 1-2 parts alkyl dimethyl benzyl ammonium chloride.

2. The stabilized soil according to claim 1, wherein Cattail fiber is carbonized cattail fiber.

3. The stabilized soil of claim 2, wherein the soil is stabilized by mixing the soil with the water-soluble polymer and the water. Carbonized cattail fiber is prepared by the following specific steps: cattail fiber is added to sodium hypochlorite aqueous solution, the pH of the system is adjusted to 3-4, stirred for 1-2 hours, heated to 70-90℃ and stirred for 10-30 minutes, filtered, washed, dried, and calcined at 900-1000℃ for 10-30 minutes under nitrogen atmosphere to obtain carbonized cattail fiber.

4. The stabilized soil of claim 3, wherein the soil is stabilized by mixing the soil with the water-soluble polymer and the water. The sodium hypochlorite aqueous solution has a mass fraction of 0.2-1%, and the mass ratio of reed fiber to sodium hypochlorite aqueous solution is 5-15:30-50.

5. The stabilized soil according to any one of claims 2 to 4, wherein the cured soil is characterized by, The diameter of carbonized cattail fibers is 1-10 μm.

6. The stabilized soil of claim 1, wherein the soil is stabilized by mixing the soil with the polymer and the water. The silicon micro powder is made by grinding quartz sand, in which particles with a diameter of less than 1μm account for more than 90% by mass and the SiO2 content is greater than 93.1%.

7. The solidified soil with enhanced flexural strength according to claim 1, characterized in that, MgO powder has a specific surface area ≥525m² 2 / kg, SiO2 content > 51.4%, Al2O3 content > 4.8%, MgO content > 26.2%.

8. A method of producing a cured soil having enhanced bending resistance according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Add zirconium oxychloride octahydrate and cerium nitrate hexahydrate to an ethanol aqueous solution and stir evenly. Add reed fiber and ultrasonically treat. Then cool to -35 to -45℃, freeze dry for 10-20h, sinter at 900-1300℃ in an oxygen atmosphere for 20-40min, and cool with the furnace to obtain pre-made bending-resistant fiber. S2. Magnesium sulfate whiskers are continuously stirred at 62-68℃ for 1-2 hours. While stirring, poly(propylene glycol)-silane-poly(ethylene glycol) is added dropwise. After the addition is complete, stirring is continued for 5-15 minutes. The mixture is then cooled to room temperature, centrifuged, and dried. Bisphenol A epoxy resin and pre-formed anti-bending fibers are added. The mixture is then degassed and stirred at room temperature for 1-2 hours to obtain composite bisphenol A epoxy resin. S3. Mix ordinary silicate cement, fly ash, montmorillonite powder, silica powder, composite bisphenol A epoxy resin, sodium silicate, polycarboxylic acid polymer, and water evenly. Add expansion agent, sodium hexametaphosphate, and alkyl dimethyl benzyl ammonium chloride and stir for 10-30 minutes. Cure at 30-35℃ for 5-10 hours to obtain soil stabilizer. Mix the soil stabilizer with soil and solidify.

9. The method of claim 8, wherein the cured soil has a bending resistance of 0.5 to 1.5 kgf / cm. In S1, the ultrasonic treatment time is 5-15 min and the ultrasonic frequency is 5-12 kHz.

10. The method of claim 8, wherein the cured soil has an increased bending resistance. During the cooling and freezing process of S1, the cooling rate is 3-7℃ / min.

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