An additive for rapidly increasing the strength of solidified soil grouting and a preparation method thereof

Abstract

The application discloses an additive for rapidly improving the grouting strength of solidified soil, and raw materials of the additive include bisphenol A epoxy resin, graphene oxide, montmorillonite, ultra-fine zeolite powder, magnesium sulfate whisker, poly(propylene glycol)-silane-poly(ethylene glycol) and phthalic anhydride.The application discloses a preparation method of the additive.The application discloses a soil solidifying agent, and raw materials of the soil solidifying agent include ordinary portland cement 20-40 parts, fly ash 10-20 parts, mineral powder 5-15 parts, steel slag 1-5 parts, sodium silicate 2-7 parts, polycarboxylic acid polymer 1-2 parts, hydrophobic nano silicon oxide 1-5 parts, the additive 2-12 parts, sodium hexametaphosphate 1-3 parts, alkyl dimethyl benzyl ammonium chloride 1-2 parts and water 100-150 parts.The application discloses a preparation method of the soil solidifying agent.The application discloses a use method of the soil solidifying agent.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solidified soil, in particular to an additive for rapidly improving the grouting strength of solidified soil and a preparation method thereof, a soil solidifying agent and a preparation method and use method thereof. BACKGROUND

[0002] The soil solidifying agent is a material for changing the engineering properties of soil through a series of physical or chemical reactions after being mixed with soil. Currently, the commonly used inorganic solidifying additive materials include cement, slag, fly ash, lime, sodium silicate and the like, which have good construction stability and low cost, and are currently widely promoted and applied. However, the existing soil solidifying agents basically need mechanical ramming and the like, and the solidified soil itself does not have fluidity, especially for liquid soil solidifying agents, which basically must be rammed to realize solidification and reinforcement of the soil body.

[0003] The existing soil solidifying agents generally have the problem of low fluidity, especially for narrow construction space, manual flattening is still needed, and if the slump of the solidified soil mixture is to be further improved, for example, the slump is more than 180 mm, a large proportion of dispersing agent needs to be added by several times, which not only greatly increases the construction cost, but also does not have a very obvious effect on the fluidity improvement by several times of the dispersing agent, and the prepared solidified soil mixture still has the defect of poor fluidity and is prone to problems such as segregation, bleeding, and hardening. SUMMARY

[0004] The present application relates to the technical field of solidified soil, in particular to an additive for rapidly improving the grouting strength of solidified soil and a preparation method thereof, a soil solidifying agent and a preparation method and use method thereof.

[0005] An additive for rapidly improving the grouting strength of solidified soil, raw materials of which include: bisphenol A epoxy resin, graphene oxide, montmorillonite, ultra-fine zeolite powder, magnesium sulfate whisker, poly(propylene glycol)-silane-poly(ethylene glycol), phthalic anhydride; the mass ratio of bisphenol A epoxy resin, graphene oxide, montmorillonite, ultra-fine zeolite powder, magnesium sulfate whisker, poly(propylene glycol)-silane-poly(ethylene glycol), phthalic anhydride is 20-40:1-2:1-5:1-5:1-5:5-15:1-2.

[0006] Preferably, the epoxy value of the bisphenol A epoxy resin is 0.42-0.54 eq / 100 g.

[0007] Preferably, the particle size of the ultra-fine zeolite powder is 10-50 nm.

[0008] Preferably, the aspect ratio of the magnesium sulfate whisker is >33.

[0009] The above-mentioned additive preparation method comprises the following steps:

[0010] S1, continuously stirring the magnesium sulfate whisker, the stirring temperature is 60-70 DEG C, in the stirring process, drop poly (propylene glycol) -silane-poly (ethylene glycol), drop completely continue stirring, drop to room temperature, then with graphene oxide dispersion in N, N-dimethylformamide, 60-70 DEG C stirring 2-5h, cooling, centrifugation, drying to get preform;

[0011] S2, the preform is added to bisphenol A epoxy resin, vacuum pumping, adding phthalic anhydride mixed uniformly, defoaming treatment, continue to add montmorillonite, superfine zeolite powder, room temperature stirring to get curing additives.

[0012] A soil stabilizer, the raw materials include: ordinary Portland cement 20-40 parts, fly ash 10-20 parts, mineral powder 5-15 parts, steel slag 1-5 parts, sodium silicate 2-7 parts, polycarboxylic acid polymer 1-2 parts, hydrophobic nano silicon oxide 1-5 parts, the above additives 2-12 parts, sodium hexametaphosphate 1-3 parts, alkyl dimethyl benzyl ammonium chloride 1-2 parts, water 100-150 parts.

[0013] The preparation method of the above soil stabilizer comprises the following steps: mixing ordinary Portland cement, fly ash, mineral powder, steel slag, sodium silicate, polycarboxylic acid polymer, hydrophobic nano silicon oxide and water uniformly to obtain a premix; adding the above additives, sodium hexametaphosphate and alkyl dimethyl benzyl ammonium chloride to the premix and stirring, curing at 25-32 DEG C for 1-4h to obtain the soil stabilizer.

[0014] The use method of the above soil stabilizer is to apply the soil stabilizer into soil, and the soil stabilizer is mixed with soil at a mass ratio of 1-2:10000 and solidified.

[0015] The technical effects of the present application are as follows:

[0016] The present application adopts the hydrophilic end of poly (propylene glycol) -silane-poly (ethylene glycol) to combine with magnesium sulfate whisker, and the hydrophobic end to combine with bisphenol A epoxy resin, which can not only promote magnesium sulfate whisker to have better dispersibility, improve the efficiency and service life of fluid soil treatment, but also does not affect the fluidity of the grouting process, greatly improving the grouting efficiency.

[0017] The soil solidifying agent takes ordinary portland cement as base material, wherein the additive not only promotes other materials to uniformly disperse in the base material, but also promotes the rapid solidification and formation of the solidified soil after the solidified soil is solidified, and the amphiphilic characteristics of the additive can promote the increase of the inter-particle attraction, which can not only reduce the total thickness of the soil particles and the solidified soil, but also enable the clay particles to gather and condense the newly generated crystal surface with hydroxyl, which can attract the bisphenol A epoxy resin to adhere to the surface, weaken the surface charge of the soil particles, make the soil and the solidifying agent components close to each other, and make the solidified soil more compact and have higher mechanical strength.

[0018] The active carboxyl groups on the graphene oxide are grafted on the magnesium sulfate structure under the action of poly(propylene glycol)-silane-poly(ethylene glycol), and the single-crystal fiber structure of magnesium sulfate and the two-dimensional lattice structure of graphene oxide are cooperatively inserted in the matrix, which not only improves the overall strength of the solidified soil, but also has a network structure of insertion and crosslinking compared with the unadded graphene oxide, so that the system stability of the solidified soil is significantly enhanced.

[0019] The solidifying agent can promote the solid particles of the solidified soil to be closely and compactly attached, reduce the voids, improve the structural strength, make the internal structure of the solidified soil compact and have high cohesive strength. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A comparison chart of the unconfined compressive strength of the soil solidified by the soil solidifying agents obtained in Example 5 and Comparative Examples 1-2 after 7 days.

[0021] Figure 2 A comparison chart of the flexural strength of the soil solidified by the soil solidifying agents obtained in Example 5 and Comparative Examples 1-2 after 25 days. DETAILED DESCRIPTION

[0022] The application will be further described below in combination with specific examples.

[0023] Example 1

[0024] An additive for rapidly improving the grouting strength of solidified soil, which raw materials include: 20 kg of bisphenol A epoxy resin with an epoxy value of 0.42 eq / 100 g, 1 kg of graphene oxide, 1 kg of montmorillonite, 1 kg of ultra-fine zeolite powder with a particle size of 10-50 nm, 1 kg of magnesium sulfate whisker with a length-diameter ratio of >33, 5 kg of poly(propylene glycol)-silane-poly(ethylene glycol), and 1 kg of phthalic anhydride.

[0025] The additive preparation method includes the following steps:

[0026] S1, continuously stirring the magnesium sulfate whiskers, the stirring temperature is 60℃, during the stirring process, drop poly(propylene glycol)-silane-poly(ethylene glycol), after the drop is completed, continue to stir, reduce to room temperature, then disperse the graphene oxide into N,N-dimethylformamide, stirring at 60℃ for 2h, cooling, centrifugation, drying to obtain the preform;

[0027] S2, add the preform into the bisphenol A epoxy resin, vacuum pumping, add phthalic anhydride and mix uniformly, defoaming treatment, continue to add montmorillonite, superfine zeolite powder, stirring at room temperature to obtain the curing additive.

[0028] A soil stabilizer, which raw materials include: ordinary Portland cement 20kg, fly ash 10kg, mineral powder 5kg, steel slag 1kg, sodium silicate 2kg, polycarboxylic acid polymer 1kg, hydrophobic nano silicon oxide 1kg, the above additives 2kg, sodium hexametaphosphate 1kg, alkyl dimethyl benzyl ammonium chloride 1kg, water 100kg.

[0029] The preparation method of the above soil stabilizer, which includes the following steps: uniformly mixing ordinary Portland cement, fly ash, mineral powder, steel slag, sodium silicate, polycarboxylic acid polymer, hydrophobic nano silicon oxide and water to obtain a premix; adding the above additives, sodium hexametaphosphate and alkyl dimethyl benzyl ammonium chloride into the premix and stirring, curing at 25℃ for 1h to obtain the soil stabilizer.

[0030] Example 2

[0031] A kind of additive for quickly improving the grouting strength of solidified soil, which raw materials include: bisphenol A epoxy resin with epoxy value of 0.54 eq / 100g 40kg, graphene oxide 2kg, montmorillonite 5kg, superfine zeolite powder with particle size of 10-50nm 5kg, magnesium sulfate whisker with aspect ratio >33 5kg, poly(propylene glycol)-silane-poly(ethylene glycol) 15kg, phthalic anhydride 2kg.

[0032] The preparation method of the above additive, which includes the following steps:

[0033] S1, continuously stirring the magnesium sulfate whiskers, the stirring temperature is 60℃, during the stirring process, drop poly(propylene glycol)-silane-poly(ethylene glycol), after the drop is completed, continue to stir, reduce to room temperature, then disperse the graphene oxide into N,N-dimethylformamide, stirring at 60℃ for 2h, cooling, centrifugation, drying to obtain the preform;

[0034] S2, add the preform into the bisphenol A epoxy resin, vacuum pumping, add phthalic anhydride and mix uniformly, defoaming treatment, continue to add montmorillonite, superfine zeolite powder, stirring at room temperature to obtain the curing additive.

[0035] A soil stabilizer, raw materials of which include: ordinary Portland cement 40 kg, fly ash 20 kg, mineral powder 15 kg, steel slag 5 kg, sodium silicate 7 kg, polycarboxylic acid polymer 2 kg, hydrophobic nano silicon oxide 5 kg, the above-mentioned additive 12 kg, sodium hexametaphosphate 3 kg, alkyl dimethyl benzyl ammonium chloride 2 kg, water 150 kg.

[0036] The preparation method of the soil stabilizer includes the following steps: mixing ordinary Portland cement, fly ash, mineral powder, steel slag, sodium silicate, polycarboxylic acid polymer, hydrophobic nano silicon oxide and water uniformly to obtain a premix; adding the above-mentioned additive, sodium hexametaphosphate and alkyl dimethyl benzyl ammonium chloride into the premix and stirring, curing at 32 DEG C for 4 h to obtain the soil stabilizer.

[0037] Example 3

[0038] An additive for rapidly improving the grouting strength of stabilized soil, raw materials of which include: bisphenol A epoxy resin with an epoxy value of 0.45 eq / 100 g 35 kg, graphene oxide 1.3 kg, montmorillonite 4 kg, ultra-fine zeolite powder with a particle size of 10-50 nm 2 kg, magnesium sulfate whisker with an aspect ratio > 33 4 kg, poly(propylene glycol)-silane-poly(ethylene glycol) 8 kg, phthalic anhydride 1.7 kg.

[0039] The preparation method of the additive includes the following steps:

[0040] S1, continuously stirring the magnesium sulfate whisker at a stirring temperature of 64 DEG C, and adding poly(propylene glycol)-silane-poly(ethylene glycol) dropwise during the stirring process; after the dropwise addition is completed, continue to stir, reduce to room temperature, then disperse the graphene oxide into N,N-dimethylformamide, stir at 68 DEG C for 3 h, cool, centrifuge and dry to obtain a pre-preparation;

[0041] S2, add the pre-preparation into bisphenol A epoxy resin, evacuate under reduced pressure, mix uniformly by adding phthalic anhydride, defoaming treatment, continue to add montmorillonite and ultra-fine zeolite powder, and stir at room temperature to obtain a curing additive.

[0042] A soil stabilizer, raw materials of which include: ordinary Portland cement 35 kg, fly ash 12 kg, mineral powder 12 kg, steel slag 2 kg, sodium silicate 5 kg, polycarboxylic acid polymer 1.3 kg, hydrophobic nano silicon oxide 4 kg, the above-mentioned additive 6 kg, sodium hexametaphosphate 2.5 kg, alkyl dimethyl benzyl ammonium chloride 1.3 kg, water 130 kg.

[0043] The preparation method of the soil stabilizer comprises the following steps: uniformly mixing ordinary Portland cement, fly ash, mineral powder, steel slag, sodium silicate, polycarboxylic acid polymer, hydrophobic nano silicon oxide and water to obtain a premix; and adding the additive, sodium hexametaphosphate and alkyl dimethyl benzyl ammonium chloride into the premix, stirring, and curing at 26 DEG C for 3 hours to obtain the soil stabilizer.

[0044] Example 4

[0045] An additive for rapidly improving the grouting strength of solidified soil, which raw materials comprise: 25 kg of bisphenol A epoxy resin with an epoxy value of 0.51 eq / 100 g, 1.7 kg of graphene oxide, 2 kg of montmorillonite, 4 kg of ultra-fine zeolite powder with a particle size of 10-50 nm, 2 kg of magnesium sulfate whiskers with an aspect ratio of >33, 12 kg of poly(propylene glycol)-silane-poly(ethylene glycol), and 1.3 kg of phthalic anhydride.

[0046] The preparation method of the additive comprises the following steps:

[0047] S1, continuously stirring the magnesium sulfate whiskers at a stirring temperature of 66 DEG C, continuously stirring while adding the poly(propylene glycol)-silane-poly(ethylene glycol), continuing to stir after the addition is completed, cooling to room temperature, then dispersing the graphene oxide into N,N-dimethylformamide, stirring at 62 DEG C for 4 hours, cooling, centrifuging, and drying to obtain a pre-preparation;

[0048] S2, adding the pre-preparation into the bisphenol A epoxy resin, vacuum pumping, uniformly mixing the phthalic anhydride, defoaming treatment, continuously adding the montmorillonite and ultra-fine zeolite powder, and stirring at room temperature to obtain the solidification additive.

[0049] A soil stabilizer, which raw materials comprise: 25 kg of ordinary Portland cement, 18 kg of fly ash, 8 kg of mineral powder, 4 kg of steel slag, 3 kg of sodium silicate, 1.7 kg of polycarboxylic acid polymer, 2 kg of hydrophobic nano silicon oxide, 8 kg of the additive, 1.5 kg of sodium hexametaphosphate, 1.7 kg of alkyl dimethyl benzyl ammonium chloride, and 110 kg of water.

[0050] The preparation method of the soil stabilizer comprises the following steps: uniformly mixing ordinary Portland cement, fly ash, mineral powder, steel slag, sodium silicate, polycarboxylic acid polymer, hydrophobic nano silicon oxide and water to obtain a premix; and adding the additive, sodium hexametaphosphate and alkyl dimethyl benzyl ammonium chloride into the premix, stirring, and curing at 26 DEG C for 3 hours to obtain the soil stabilizer.

[0051] Example 5

[0052] An additive for rapidly improving the grouting strength of solidified soil, raw materials of which include: bisphenol A epoxy resin with an epoxy value of 0.48 eq / 100g 30 kg, graphene oxide 1.5 kg, montmorillonite 3 kg, ultra-fine zeolite powder with a particle size of 10-50 nm 3 kg, magnesium sulfate whisker with an aspect ratio >33 3 kg, poly(propylene glycol)-silane-poly(ethylene glycol) 10 kg, phthalic anhydride 1.5 kg.

[0053] The additive preparation method comprises the following steps:

[0054] S1, continuously stirring the magnesium sulfate whisker at a stirring temperature of 65 DEG C, and adding the poly(propylene glycol)-silane-poly(ethylene glycol) dropwise during the stirring process; after the dropwise addition is completed, continue stirring, reduce to room temperature, and then disperse the graphene oxide in N,N-dimethylformamide; stir at 65 DEG C for 3.5 h, cool, centrifuge, and dry to obtain a pre-preparation;

[0055] S2, add the pre-preparation into the bisphenol A epoxy resin, evacuate under reduced pressure, mix uniformly after adding the phthalic anhydride, perform defoaming treatment, continue to add the montmorillonite and the ultra-fine zeolite powder, and stir at room temperature to obtain the solidification additive.

[0056] A soil solidification agent, raw materials of which include: ordinary portland cement 30 kg, fly ash 15 kg, mineral powder 10 kg, steel slag 3 kg, sodium silicate 4 kg, polycarboxylic acid polymer 1.5 kg, hydrophobic nano silicon oxide 3 kg, the additive 7 kg, sodium hexametaphosphate 2 kg, alkyl dimethyl benzyl ammonium chloride 1.5 kg, and water 120 kg.

[0057] The soil solidification agent preparation method comprises the following steps: uniformly mix the ordinary portland cement, the fly ash, the mineral powder, the steel slag, the sodium silicate, the polycarboxylic acid polymer, the hydrophobic nano silicon oxide, and the water to obtain a pre-mixture; add the additive, the sodium hexametaphosphate, and the alkyl dimethyl benzyl ammonium chloride into the pre-mixture and stir, and then maintain at 28 DEG C for 2.5 h to obtain the soil solidification agent.

[0058] Comparative Example 1

[0059] An additive for rapidly improving the grouting strength of solidified soil, raw materials of which include: bisphenol A epoxy resin with an epoxy value of 0.48 eq / 100g 30 kg, montmorillonite 3 kg, ultra-fine zeolite powder with a particle size of 10-50 nm 3 kg, magnesium sulfate whisker with an aspect ratio >33 3 kg, poly(propylene glycol)-silane-poly(ethylene glycol) 10 kg, phthalic anhydride 1.5 kg.

[0060] The additive preparation method comprises the following steps:

[0061] i. continuously stirring the magnesium sulfate whiskers at a temperature of 65°C, adding poly(propylene glycol)-silane-poly(ethylene glycol) dropwise during the stirring, continuing the stirring after the dropwise addition is complete, reducing to room temperature, then dispersing into N,N-dimethylformamide, stirring at 65°C for 3.5h, cooling, centrifuging, and drying to obtain a pre-preparation;

[0062] ii. adding the pre-preparation into bisphenol A epoxy resin, vacuuming, adding phthalic anhydride and mixing uniformly, defoaming treatment, continuously adding montmorillonite and ultra-fine zeolite powder, and stirring at room temperature to obtain a solidification additive.

[0063] A soil solidification agent, raw materials of which include: ordinary Portland cement 30 kg, fly ash 15 kg, mineral powder 10 kg, steel slag 3 kg, sodium silicate 4 kg, polycarboxylic acid polymer 1.5 kg, hydrophobic nano silicon oxide 3 kg, the above-mentioned additive 7 kg, sodium hexametaphosphate 2 kg, alkyl dimethyl benzyl ammonium chloride 1.5 kg, and water 120 kg.

[0064] The preparation method of the above-mentioned soil solidification agent includes the following steps: uniformly mixing ordinary Portland cement, fly ash, mineral powder, steel slag, sodium silicate, polycarboxylic acid polymer, hydrophobic nano silicon oxide, and water to obtain a pre-mixture; adding the above-mentioned additive, sodium hexametaphosphate, and alkyl dimethyl benzyl ammonium chloride into the pre-mixture and stirring, curing at 28°C for 2.5h to obtain the soil solidification agent.

[0065] Comparative Example 2

[0066] An additive for rapidly improving the grouting strength of solidified soil, raw materials of which include: bisphenol A epoxy resin with an epoxy value of 0.48 eq / 100g 30 kg, graphene oxide 1.5 kg, montmorillonite 3 kg, ultra-fine zeolite powder with a particle size of 10-50 nm 3 kg, magnesium sulfate whiskers with an aspect ratio >33 3 kg, and phthalic anhydride 1.5 kg.

[0067] The preparation method of the above-mentioned additive includes the following steps:

[0068] i. dispersing the magnesium sulfate whiskers and graphene oxide into N,N-dimethylformamide, stirring at 65°C for 3.5h, cooling, centrifuging, and drying to obtain a pre-preparation;

[0069] ii. adding the pre-preparation into bisphenol A epoxy resin, vacuuming, adding phthalic anhydride and mixing uniformly, defoaming treatment, continuously adding montmorillonite and ultra-fine zeolite powder, and stirring at room temperature to obtain a solidification additive.

[0070] A soil stabilizer, the raw materials of which include: 30 kg of ordinary silicate cement, 15 kg of fly ash, 10 kg of mineral powder, 3 kg of steel slag, 4 kg of sodium silicate, 1.5 kg of polycarboxylate polymer, 3 kg of hydrophobic nano-silica, 7 kg of the above additives, 2 kg of sodium hexametaphosphate, 1.5 kg of alkyl dimethyl benzyl ammonium chloride, and 120 kg of water.

[0071] The preparation method of the above-mentioned soil stabilizer includes the following steps: ordinary silicate cement, fly ash, mineral powder, steel slag, sodium silicate, polycarboxylate polymer, hydrophobic nano-silica, and water are mixed evenly to obtain a premix; the above-mentioned additives, sodium hexametaphosphate, and alkyl dimethyl benzyl ammonium chloride are added to the premix and stirred, and cured at 28°C for 2.5 hours to obtain the soil stabilizer.

[0072] The soil stabilizer obtained in Example 5 and Comparative Examples 1-2 was mixed with soil at a mass ratio of 1.5:10000, placed in a plastic bag, and sealed and cured in a loose state for 24 hours. Then, its liquid limit, plastic limit and plasticity index were tested.

[0073] Example 5 Comparative Example 1 Comparative Example 2 Liquid limit 45.8 43.9 43.3 Plastic limit 27.9 25.8 23.9 Plasticity index 17.9 18.1 19.4

[0074] As shown in the table above, the soil stabilizer obtained in Example 5 resulted in the largest decrease in plasticity index, indicating that the soil stabilizer obtained in Example 5 can effectively reduce the thickness of the bound water film, reduce the spacing between soil particles, and enhance the bonding force between soil particles.

[0075] Meanwhile, a comparison of the state of the soil stabilizer after mixing with the soil revealed that the soil stabilizers obtained in Example 5 and Comparative Example 1 had better fluidity and construction performance than those in Comparative Example 2. The applicant believes this is because the hydrophilic end of poly(propylene glycol)-silane-poly(ethylene glycol) is combined with magnesium sulfate whiskers, while the hydrophobic end is combined with bisphenol A epoxy resin. This not only promotes better dispersibility of the magnesium sulfate whiskers, improving the efficiency and service life of fluid treatment of soil, but also does not affect the fluidity of the grouting process.

[0076] The soil stabilizers obtained in Example 5 and Comparative Examples 1-2 were mixed with soil at a mass ratio of 1.5:10000, 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.

[0077] 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.

[0078] The unconfined compressive strength of the cured soil with a compaction degree of 98% of the Example 5 group reached 1.89 Mpa, which is better than the other two groups, indicating that the soil solidifying agent obtained in Example 5 has a better solidifying effect than Comparative Examples 1 and 2. The applicant believes that this is because the additive used in the application is compounded by bisphenol A epoxy resin and poly(propylene glycol)-silane-poly(ethylene glycol), which promotes the rapid solidification of the cured soil and forms a whole. At the same time, the amphiphilic characteristics of the additive can increase the interparticle attraction, which can not only reduce the overall thickness of the soil particles and the cured soil, but also enable the clay particles to aggregate and condense the newly generated crystal surface with hydroxyl groups, which can attract bisphenol A epoxy resin to adhere to the surface, weaken the surface charge of the soil particles, and make the soil and the solidifying agent components close to each other, so that the cured soil is more compact and has higher mechanical strength. At the same time, the active carboxyl groups on the graphene oxide are grafted onto the magnesium sulfate structure under the action of poly(propylene glycol)-silane-poly(ethylene glycol), and the single crystal fiber structure of magnesium sulfate and the two-dimensional lattice structure of graphene oxide are cooperatively interpenetrated in the matrix, which not only improves the overall strength of the cured soil, but also significantly enhances the system stability of the cured soil compared with the additive without graphene oxide.

[0079] The soil solidifying agent obtained in Example 5 and Comparative Examples 1-2 was used to solidify the soil at a mass ratio of 1.5:10000, and after 25d of curing, the flexural strength test was carried out according to the test procedure of the flexural strength test in GB / T 50081-2016 “Standard for Testing Methods of Mechanical Properties of Ordinary Concrete”, as shown in Figure 2

[0080] The 25d flexural strength of the Example 5 group is much better than the comparative examples, and the applicant believes that this is because the additive used in the application is compounded by bisphenol A epoxy resin and poly(propylene glycol)-silane-poly(ethylene glycol), which promotes the rapid solidification of the cured soil and forms a whole, and promotes the increase of interparticle attraction, which can not only reduce the overall thickness of the soil particles and the cured soil, but also weaken the surface charge of the soil particles, and make the soil and the solidifying agent components close to each other, so that the cured soil is more compact and has higher mechanical strength. At the same time, the active carboxyl groups on the graphene oxide are grafted onto the magnesium sulfate structure under the action of poly(propylene glycol)-silane-poly(ethylene glycol), and the single crystal fiber structure of magnesium sulfate and the two-dimensional lattice structure of graphene oxide are cooperatively interpenetrated in the matrix, which improves the overall strength of the cured soil and significantly enhances the system stability of the cured soil.

[0081] The above is only the preferred specific embodiment of the application, but the protection scope of the application is not limited to this. Any person skilled in the art can make equivalent substitutions or changes within the technical scope disclosed in the application and according to the technical solution and inventive concept of the application, which should be covered within the protection scope of the application.​

Claims

1. An additive for rapidly improving the grouting strength of solidified soil, characterized in that, Its raw materials include: bisphenol A epoxy resin, graphene oxide, montmorillonite, ultrafine zeolite powder, magnesium sulfate whiskers, poly(propylene glycol)-silane-poly(ethylene glycol), and phthalic anhydride; the mass ratio of bisphenol A epoxy resin, graphene oxide, montmorillonite, ultrafine zeolite powder, magnesium sulfate whiskers, poly(propylene glycol)-silane-poly(ethylene glycol), and phthalic anhydride is 20-40:1-2:1-5:1-5:1-5:5-15:1-2.

2. The additive for rapidly improving the grouting strength of solidified soil according to claim 1, characterized in that, The epoxy value of bisphenol A epoxy resin is 0.42-0.54 eq / 100g.

3. The additive for rapidly improving the grouting strength of solidified soil according to claim 1, characterized in that, The particle size of ultrafine zeolite powder is 10-50 nm.

4. The additive for rapidly improving the grouting strength of solidified soil according to claim 1, characterized in that, The aspect ratio of magnesium sulfate whiskers is >33.

5. A method for preparing an additive as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Magnesium sulfate whiskers are continuously stirred at a temperature of 60-70℃. During the stirring process, poly(propylene glycol)-silane-poly(ethylene glycol) is added dropwise. After the addition is complete, stirring is continued. The mixture is cooled to room temperature and then dispersed with graphene oxide in N,N-dimethylformamide. The mixture is stirred at 60-70℃ for 2-5 hours, cooled, centrifuged, and dried to obtain the preform. S2. Add the pre-made material to the bisphenol A epoxy resin, depressurize and evacuate the air, add phthalic anhydride and mix evenly, degas the mixture, and then add montmorillonite and ultrafine zeolite powder. Stir at room temperature to obtain the curing additive.

6. A soil stabilizer, characterized in that, The raw materials, by weight, include: 20-40 parts of ordinary silicate cement, 10-20 parts of fly ash, 5-15 parts of mineral powder, 1-5 parts of steel slag, 2-7 parts of sodium silicate, 1-2 parts of polycarboxylate polymer, 1-5 parts of hydrophobic nano-silica, 2-12 parts of the additives as described in any one of claims 1-4, 1-3 parts of sodium hexametaphosphate, 1-2 parts of alkyl dimethyl benzyl ammonium chloride, and 100-150 parts of water.

7. A method for preparing the soil stabilizer as described in claim 6, characterized in that, The process includes the following steps: mixing ordinary silicate cement, fly ash, mineral powder, steel slag, sodium silicate, polycarboxylate polymer, hydrophobic nano-silica, and water evenly to obtain a premix; adding the additives described in any one of claims 1-4, sodium hexametaphosphate, and alkyl dimethyl benzyl ammonium chloride to the premix and stirring, then curing at 25-32℃ for 1-4 hours to obtain a soil stabilizer.

8. A method of using the soil stabilizer as described in claim 6, characterized in that, The soil stabilizer as described in claim 6 is applied to the soil, and the soil stabilizer is mixed with the soil at a mass ratio of 1-2:10000 and then stabilized.

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