CN113307535A

CN113307535A - Soil curing agent

Info

Publication number: CN113307535A
Application number: CN202110679096.9A
Authority: CN
Inventors: 陶祥令; 于庆; 马金荣; 朱科企
Original assignee: Jiangsu Jianzhu Institute
Current assignee: Jiangsu Jianzhu Institute
Priority date: 2021-06-18
Filing date: 2021-06-18
Publication date: 2021-08-27

Abstract

The invention discloses a soil solidifying agent, comprising 20-30 parts of sodium carbonate, 15-20 parts of calcium chloride, 15-20 parts of calcium sulfate, 30-40 parts of polymerized iron sulfate, 5-8 parts of magnesium oxide and potassium phosphate 5-8 parts, 10-12 parts of modified cellulose, 5-7 parts of nano zeolite, and 6-8 parts of repairing microcapsules are mixed in proportion; The weight parts of mud, 2-2.5 parts of fly ash, 2-5 parts of ordinary Portland cement, and 95-97 parts of plain soil are mixed by a mixing device, then spread and maintained; the solidified soil has strong impermeability It also has good complexation and curing effect on heavy metal ions, is not easy to seep out, and has recyclability. The curing agent and soil are evenly dispersed, and the overall curing effect is good.

Description

Soil curing agent

Technical Field

The invention relates to the field of solidification of novel geotechnical materials, in particular to a soil solidifying agent.

Background

The soil is substantially a colloidal sol, the colloidal sol has certain stability, a certain distance is maintained between colloidal particles, the difference of soil strength is large along with the change of water content, soil with high compactness and high strength is required in the projects of road construction, geological disaster prevention and control, water conservancy and hydropower seepage prevention and leakage prevention and the like, the structural effect of the soil and the water-containing state of the solidified soil are required to be changed, chemical substances are added into the soil to change the property of the soil, and the construction effect is beneficial.

The soil stabilizer is a new energy-saving environment-friendly engineering material synthesized by various inorganic and organic materials and used for curing various soils, the soil to be reinforced can reach the required performance index only by adding a certain amount of stabilizer according to the physical and chemical properties of the soil, and through uniform stirring and compaction treatment, compared with the road building using the traditional road surface base material, the road building cost can be saved, the construction period can be shortened, the unconfined compressive strength can be improved under the condition of not changing the construction conditions, the soil stabilizer composite solidified soil specimen can not be dissolved by soaking in water at normal temperature, the water stability is good, the durability is good, and the like, the macromolecule soil stabilizer is applied to a plurality of fields due to high concentration, less dosage, easy transportation and convenient construction in the actual application, but the impermeability, freeze-thaw resistance and the compressive resistance of the macromolecule stabilizer are further improved to meet the requirement of being applicable to more fields, the traditional inorganic soil curing agent mainly comprises a lime cement soil curing agent, which is also the preferred soil curing agent type in the conventional railway roadbed foundation treatment, and a cementing component is formed after the lime cement soil curing agent is combined with water in soil, so that the aim of cementing the soil is finally fulfilled, the stability and the shear strength of the soil are improved, but the problems of deformation, cracking and the like easily occur.

In addition, some soils are often dispersed with a lot of heavy metal ions due to environmental pollution, and how to solidify and recover the heavy metal ions is also a problem to be solved in the current soil solidification.

Disclosure of Invention

In view of the above situation, the present invention aims to provide a soil stabilizer, which has strong impermeability, freeze-thaw resistance, compressive resistance, deformation resistance, cracking resistance, long service life, self-repairing property, and good curing effect on heavy metal ions.

The technical scheme for solving the problem is as follows:

the soil stabilizer is prepared from the following raw materials in parts by weight: 20-30 parts of sodium carbonate, 15-20 parts of calcium chloride, 15-20 parts of calcium sulfate, 30-40 parts of polymeric ferric sulfate, 5-8 parts of magnesium oxide, 5-8 parts of potassium phosphate, 10-12 parts of modified cellulose, 5-7 parts of nano zeolite and 6-8 parts of repair microcapsule;

preparing the modified cellulose: (1) FeCl is added₃·6H₂0 and FeS0₄·7H₂Dissolving 0 in deionized water, heating in a water bath at 70-80 ℃ for 3-5min, dropwise adding ammonia water, stirring at 800rpm for 20-30min, finally performing magnetic separation on the product, and washing with distilled water until the pH is =5-6 to obtain ferroferric oxide magnetic nanoparticles; (2) dissolving cellulose sodium sulfate, corn starch, polyacrylonitrile and alpha-cyclodextrin in a mixed solution of distilled water and DMF, stirring for 30-45min at 500rpm of 400 plus materials, then adding ferroferric oxide magnetic nanoparticles, dropwise adding a polyethyleneimine water solution, stirring for 45-60min at 800rpm of 600 plus materials, dropwise adding a glutaraldehyde solution, continuously stirring for 3-4h at 45-60 ℃, cooling to room temperature, carrying out vacuum filtration, repeatedly washing with distilled water until the pH is =5-6, drying at 45-60 ℃, grinding and sieving with a 200-mesh sieve to obtain modified fibers;

the preparation of the repair microcapsule comprises the following steps: (1) adding gelatin into distilled water at room temperature, stirring at 800-; (2) n is a radical of₂Under the environment, uniformly stirring hexamethylene diisocyanate, isophorone diisocyanate and ethyl acetate, slowly adding an emulsifier mixed solution, emulsifying at 1100r/min of 1000 ℃ for 10-20min, finally adding a formaldehyde solution with the mass fraction of 37%, reacting at 50-55 ℃ for 3-4h, cooling to room temperature, filtering, washing a filter cake, and airing at room temperature to obtain a repair capsule with the particle size of 80-100 um;

the preparation of the soil stabilizer comprises the following steps: uniformly mixing the modified cellulose, the repair microcapsule and the nano zeolite according to the weight parts, and then adding the sodium carbonate, the calcium chloride, the calcium sulfate, the polymeric ferric sulfate, the magnesium oxide and the potassium phosphate according to the weight parts to uniformly mix again;

the use method of the soil stabilizer comprises the following steps: adding 95-97 parts of plain soil into a screening chamber of a mixing device in batches, carrying out grading screening, screening out large-particle impurities such as broken stones and the like, feeding the screened plain soil into a mixing chamber, sequentially passing 3-5 parts of red mud, 0.05-1 part of curing agent, 2-2.5 parts of fly ash and 2-5 parts of ordinary portland cement through a grinding chamber of the mixing device, feeding the mixture into the mixing chamber of the mixing device, fully and uniformly mixing, and then carrying out subsequent spreading and maintenance.

Further, FeCl is added in the step (1) of preparing the modified cellulose₃·6H₂0:FeS0₄·7H₂The mass volume ratio of 0 to deionized water to ammonia water is as follows: 6-7g, 4-6g, 100-120mL, 15-17 mL.

Further, in the step (2) of preparing the modified cellulose, the mass-to-volume ratio of sodium cellulose sulfate, corn starch, polyacrylonitrile, alpha-cyclodextrin, distilled water, DMF, ferroferric oxide magnetic nanoparticles, polyethyleneimine water solution and glutaraldehyde solution is as follows: 6.8-7.2g, 4.3-4.5g, 8.8-10.2g, 5.5-6.5g, 50-60mL, 30-40mL, l.2-1.6g, 5-6mL, 20-22 mL.

Further, the mass fraction of polyethyleneimine in the polyethyleneimine water solution is 30%; the mass fraction of the glutaraldehyde solution is 3.0%.

Further, in the preparation of the repairing microcapsule, the mass volume ratio of gelatin to distilled water to urea to ammonium chloride to resorcinol to hexamethylene diisocyanate to isophorone diisocyanate to ethyl acetate to formaldehyde is as follows: 2.4-4.8g, 100-120mL, 3.2-4.5g, 4.4-5.0g, 7.2-7.8g, 6.6-7.3g, 6-8mL, 10-12 mL.

Furthermore, the water content of the plain soil is 20-60%.

Furthermore, the mixing device comprises a screening chamber, a collecting chamber, a mixing chamber and a grinding chamber; the screening chamber comprises a screening chamber shell, an upper layer screening membrane and a lower layer screening membrane are arranged on the screening chamber shell, the upper layer screening membrane does not allow broken stone particles to pass through, the lower layer screening membrane only allows particles with the size of soil to pass through, telescopic rakes are arranged above the upper layer screening membrane and the lower layer screening membrane, the telescopic rake comprises a metal grid layer, a telescopic rod is connected on the metal grid layer, the telescopic rod is connected with a telescopic cylinder, the telescopic cylinder is fixed on the screening chamber shell, the telescopic rake above the upper screening membrane moves the crushed stone particles into a collecting chamber at the right part of the upper screening membrane, meanwhile, the soil is pressed on the lower layer screening film, the flexible harrow above the lower layer screening film moves the impurities larger than the soil particles into the collection chamber at the right part of the lower layer screening film, meanwhile, extruding soil to pass through the lower-layer screening membrane, wherein inclined baffles are arranged below the upper-layer screening membrane and the lower-layer screening membrane, and the bottom of the screening chamber is communicated with the upper part of the mixing chamber; the upper part of the mixing chamber is communicated with the bottom of the grinding chamber, a mixing structure is arranged in the mixing chamber, and an outlet is arranged at the bottom of the mixing chamber; the grinding chamber comprises a hopper-shaped grinding shell, a material inlet and a motor are arranged at the top of the hopper-shaped grinding shell, a motor shaft faces downwards and is connected with a grinding sheet, the grinding sheet is located above the bottom of the hopper-shaped grinding shell, the bottom of the hopper-shaped grinding shell is a grid plate, and the grinding sheet and the grid plate move relatively to extrude and disperse large particles of added materials.

Polyferric sulfate is often regarded as an excellent performance's inorganic polymer coagulant in traditional curing agent, in this application, polyferric sulfate is except as the flocculating agent, adsorb electrified soil flocculation and coagulation, still take place copolymerization with calcium chloride, form the polymeric sulfuric acid of calcification, the soil before the solidification gathers into a group, surface adsorptivity is strong, it is difficult to get rid of to wrap up moisture in it, and the polymeric sulfuric acid of newly-formed calcification then can dissociate into the soil of group, make soil structure loose blocking, reduced the holding ability of granule to adsorbed water and bound water, more do benefit to the desorption of soil moisture.

The corn starch has more branched hydrophilic substances, can form hydrogen bonds with water, and has good binding force; alpha-cyclodextrin is a substance having a hydrophilic outer edge and a hydrophobic inner cavity, and thus it can provide a hydrophobic binding site like an enzyme, serving as a host to encapsulate various suitable guest substances such as organic molecules, inorganic ions, etc.; the viscosity increasing effect of the cellulose ether can endow cement, red mud and soil with excellent viscosity, the bonding capacity of the cement, red mud and soil is obviously increased, the anti-sagging performance of the soil is improved, the uniformity and the anti-dispersion capacity of the soil can be increased, the layering, segregation and bleeding of the solidified soil are prevented, but the situation that the viscosity of the cellulose ether is obviously reduced and the viscosity increasing effect is lost sometimes occurs, sodium sulfate is a common additive in cement-based materials, and inorganic salt can cause salting-out of a cellulose ether solution, therefore, the application copolymerizes cellulose sodium sulfate with corn starch, alpha-cyclodextrin, polyacrylonitrile and polyethyleneimine through glutaraldehyde, and loads ferroferric oxide magnetic nanoparticles to obtain modified fibers, so that the salting-out defect brought by the cellulose ether can be reduced, and the modified fibers are endowed with excellent flexibility and tensile strength by the polyethyleneimine, the polyacrylonitrile and the corn starch endow the polyacrylonitrile and the corn starch with super-good water absorption performance and good salinity buffer performance, the cellulose sodium sulfate endows the cellulose sodium sulfate with excellent viscosity performance, and the alpha-cyclodextrin endows the cellulose sodium sulfate with good water absorption and complexing heavy metal and organic pollutant fixing performance, and the ferroferric oxide magnetic nanoparticles can be added to extract heavy metals and organic matters in soil through magnetic recovery before the soil is redeveloped after solidification and abandonment, so that permanent pollution is avoided.

The cement/fly ash/red mud is synergistic in solidifying soil, and Ca exists in calcium sulfate, sodium carbonate and colloid after cement hydration²⁺And OH^-While the mineral surface constituting the red mud will carry Na⁺、K⁺，Ca²⁺Can be mixed with Na in red mud⁺、K⁺Exchange action is carried out, so that particle groups are formed around the red mud particles, hydrate has strong adsorption action, metal ions are fixed in an adsorption and wrapping mode, the alkalinity of the soil is increased, and the heavy metals can be precipitated into silicate, carbonate and hydroxide. The active silicon oxide particles in the fly ash and the alumina in the fly ash are subjected to depolymerization-polycondensation reaction in a strong alkali environment, and then pass through hydrate Ca (OH) of cement₂The further alkali excitation of the modified fiber is depolymerized and condensed to form a gel substance with a network gel structure, the modified fiber is adsorbed and wrapped on heavy metal ions, and the hydration products refine the pore structure and seal pollutants. When the mass ratio of the red mud to the fly ash to the cement is 4:1:8, more gelled substances are formed, the curing strength is higher, and the leaching rate of metal ions is low.

Magnesium oxide as activator in solidified soil, and K₂PO₄And water through combination to form MgKSO₄·6H₂0 to form a compact whole, and the zeolite is a three-dimensional framework-like silicate mineral, the interior of the crystal lattice of the zeolite is provided with a plurality of cavities and channels, and the large diffusibility can be generated, and in the framework-like silicate structure, 0 (Si + A1) is constantly equal to 2, and A1³⁺Isomorphously substitutable Si in tetrahedra⁴⁺And permanent negative charges are generated, so that the porosity in the solidified body is reduced by doping the zeolite, the median pore diameter and the average pore diameter are reduced, the solidified body is more compact, the probability of generating communicated pores inside the solidified body is lower, the mechanical solidification effect on metal ions is enhanced, and meanwhile, the lower porosity is also beneficial to improving the freeze-thaw resistance and soaking resistance of the solidified body.

The curing agent is doped with the repair microcapsule with isocyanate coated by polyurethane-polyurea formaldehyde, the active component isocyanate of the repair microcapsule is very easy to react with moisture in the environment and then cross-linked and cured with the modified fiber to achieve the self-repair purpose, no catalyst is needed during the cross-linking reaction, and the mutual permeation of the self-repair liquid and the catalyst can be prevented. When the cured soil has slight cracks, the capsule wall of the repair microcapsule at the crack is broken, the isocyanate repair liquid seeping from the wall core reacts with water, and then is crosslinked and cured with the modified fiber, so that the self-repair efficiency of the cured soil can be effectively realized, and the service life of the cured soil is prolonged.

The curing agent can be used for curing soil, and the cured soil is used as a roadbed, so that the later-stage bonding with a concrete pavement is facilitated, the layering is reduced, and the service life of a railway and a highway is prolonged.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following advantages;

1. after the soil curing agent disclosed by the invention is used for curing soil, the soil curing agent has stronger impermeability, freeze-thaw resistance and compressive resistance.

2. The soil cured by the soil curing agent has stable property, long service life and self-repairing property.

3. The soil stabilizer provided by the invention has a good complexing and curing effect on heavy metal ions and organic pollutants in soil, is not easy to seep out, and has recyclability.

4. The soil curing agent, the using method and the using device have the advantages that the soil curing agent and the soil are uniformly dispersed, the integral curing effect is good, and the condition of local curing unevenness is not easy to occur.

Drawings

FIG. 1 is a diagram of a mixing apparatus according to the present invention.

Detailed Description

The foregoing and other technical and scientific aspects, features and utilities of the present invention will be apparent from the following detailed description of the embodiments, which is to be read in connection with the accompanying drawings of fig. 1. The structural contents mentioned in the following embodiments are all referred to the attached drawings of the specification.

Example 1

The soil stabilizer is prepared from the following raw materials in parts by weight: 20 parts of sodium carbonate, 15 parts of calcium chloride, 15 parts of calcium sulfate, 30 parts of polymeric ferric sulfate, 5 parts of magnesium oxide, 5 parts of potassium phosphate, 10 parts of modified cellulose, 5 parts of nano zeolite and 6 parts of repair microcapsule;

preparing the modified cellulose: (1) FeCl is added₃·6H₂06 g and FeS0₄·7H₂04 g of ferroferric oxide magnetic nano-particles are dissolved in 100mL of deionized water, heated in a 70 ℃ water bath for 3min, dropwise added with 15mL of ammonia water, stirred at 600rpm for 20min, and finally subjected to magnetic separation, and washed with distilled water until the pH is =5, so that ferroferric oxide magnetic nano-particles are obtained; (2) dissolving 6.8g of cellulose sodium sulfate, 4.3g of corn starch, 8.8g of polyacrylonitrile and 5.5g of alpha-cyclodextrin in a mixed solution of 50mL of distilled water and 30mL of DMF (dimethyl formamide), stirring at 400rpm for 30min, then adding l.2g of ferroferric oxide magnetic nanoparticles, dropwise adding 5mL of 30% polyethyleneimine aqueous solution, stirring at 600rpm for 45min, dropwise adding 20mL of 3.0% glutaraldehyde solution, continuously stirring at 45 ℃ for 3h, cooling to room temperature, carrying out vacuum filtration, repeatedly washing with distilled water until the pH is =5, drying at 45 ℃, and grinding through a 100-mesh sieve to obtain modified fibers;

the preparation of the repair microcapsule comprises the following steps: (1) 2.4g of gelatin was added to 100mL of distilled water at room temperature, and stirred at 800rpmAfter 20min, sequentially adding 3.2g of urea, 4.4g of ammonium chloride and 4.2g of resorcinol, continuously stirring for 20min, and then adjusting the pH of the mixed solution to 3.0 to obtain an emulsifier mixed solution; (2) n is a radical of₂Under the environment, uniformly stirring 7.2g of hexamethylene diisocyanate, 6.6g of isophorone diisocyanate and 6mL of ethyl acetate, slowly adding an emulsifier mixed solution, emulsifying for 10min at 1000r/min, finally adding 10mL of formaldehyde solution with the mass fraction of 37%, reacting for 3h at 50 ℃, cooling to room temperature, filtering, washing a filter cake, and airing at room temperature to obtain a repair capsule with the particle size of 80-100 um;

the use method of the soil stabilizer comprises the following steps: adding 95 parts of plain soil into a screening chamber of a mixing device in batches, carrying out grading screening, screening out large-particle impurities such as broken stones and the like to a collecting chamber of the mixing device, feeding the screened plain soil into a mixing chamber, sequentially passing 3 parts of red mud, 0.05 part of curing agent, 2 parts of fly ash and 2 parts of ordinary portland cement through a grinding chamber of the mixing device, dispersing some aggregated particles, then feeding the particles into the mixing chamber of the mixing device, fully and uniformly mixing, then carrying out subsequent spreading and maintenance, and using the particles such as broken stones and the like collected by the collecting chamber for subsequent spreading of a road surface behind a roadbed; the water content of the plain soil is 20%.

The mixing device comprises a screening chamber, a collecting chamber, a mixing chamber and a grinding chamber; the screening chamber comprises a screening chamber shell 20, an upper layer screening membrane and a lower layer screening membrane are arranged on the screening chamber shell 20, the upper layer screening membrane 4 does not allow broken stone particles to pass through, the lower layer screening membrane only allows particles with the size of soil to pass through 9, telescopic rakes are arranged above the upper layer screening membrane and the lower layer screening membrane respectively and comprise a metal grid layer 3, a telescopic rod 21 is connected to the metal grid layer 3 and is connected with a telescopic cylinder 22, the telescopic cylinder 22 is fixed on the screening chamber shell 1, the broken stone particles are moved into a collecting chamber 5 at the right part of the upper layer screening membrane 5 by the telescopic rakes at the upper layer screening membrane 4 and are pressed onto the lower layer screening membrane 9, impurities larger than the soil particles are moved into a collecting chamber 10 at the right part of the lower layer screening membrane 9 by the telescopic rakes at the upper layer screening membrane 9, the soil is simultaneously extruded through the lower layer screening membrane 9, inclined baffles 2 are arranged below the upper layer screening membrane and the lower layer screening membrane, the bottom of the screening chamber shell 1 is communicated with the upper part of the mixing chamber shell 11; the upper part of the mixing chamber shell 11 is communicated with the bottom of the grinding chamber shell 18, a mixing structure is arranged in the mixing chamber shell 11, and an outlet 13 is arranged at the bottom of the mixing chamber shell 11; the grinding chamber comprises a hopper-shaped grinding shell 18, a material inlet 14 and a motor 15 are arranged at the top of the hopper-shaped grinding shell 18, a motor shaft faces downwards and is connected with a grinding sheet 17, the grinding sheet 16 is positioned above the bottom of the hopper-shaped grinding shell 18, a grid plate 17 is arranged at the bottom of the hopper-shaped grinding shell 18, and the grinding sheet 16 and the grid plate 17 move relatively to extrude and disperse large particles of added materials.

Example 2

The soil stabilizer is prepared from the following raw materials in parts by weight: 25 parts of sodium carbonate, 17 parts of calcium chloride, 17 parts of calcium sulfate, 35 parts of polymeric ferric sulfate, 6 parts of magnesium oxide, 6 parts of potassium phosphate, 11 parts of modified cellulose, 6 parts of nano zeolite and 7 parts of repair microcapsule;

preparing the modified cellulose: (1) FeCl is added₃·6H₂06.5 g and FeS0₄·7H₂04.5 g of the ferroferric oxide magnetic nano-particles are dissolved in 110mL of deionized water, heated in a water bath at 75 ℃ for 4min, dropwise added with 16mL of ammonia water, stirred at 700rpm for 25min, and finally subjected to magnetic separation, and washed with distilled water until the pH is =5.5, so that the ferroferric oxide magnetic nano-particles are obtained; (2) dissolving 7.0g of cellulose sodium sulfate, 4.4g of corn starch, 9.2g of polyacrylonitrile and 6.0g of alpha-cyclodextrin in a mixed solution of 55mL of distilled water and 35mL of DMF (dimethyl formamide), stirring at 450rpm for 37min, then adding 1.4g of ferroferric oxide magnetic nanoparticles, dropwise adding 5.5mL of 30% polyethyleneimine aqueous solution, stirring at 700rpm for 52min, dropwise adding 21mL of 3.0% glutaraldehyde solution, continuously stirring at 52 ℃ for 3.5h, cooling to room temperature, carrying out vacuum filtration, repeatedly washing with distilled water until the pH is =5.5, drying at 52 ℃, and grinding through a 150-mesh sieve to obtain modified fibers;

the preparation of the repair microcapsule comprises the following steps: (1) adding gelatin 3.6g into distilled water 110mL at room temperature, stirring at 900rpm for 25min, and sequentially adding3.8g of urea, 4.7g of ammonium chloride and 4.3g of resorcinol, continuously stirring for 25min, and then adjusting the pH of the mixed solution to 3.0 to obtain an emulsifier mixed solution; (2) n is a radical of₂Under the environment, uniformly stirring 7.5g of hexamethylene diisocyanate, 7.0g of isophorone diisocyanate and 7mL of ethyl acetate, slowly adding an emulsifier mixed solution, emulsifying for 15min at 1050r/min, finally adding 11mL of formaldehyde solution with the mass fraction of 37%, reacting for 3.5h at 52 ℃, cooling to room temperature, filtering, washing a filter cake, and airing at room temperature to obtain a repair capsule with the particle size of 80-100 um;

the use method of the soil stabilizer comprises the following steps: adding 96 parts of plain soil into a screening chamber of a mixing device in batches, carrying out grading screening, screening out large-particle impurities such as broken stones and the like to a collecting chamber of the mixing device, enabling the screened plain soil to enter a mixing chamber, sequentially enabling 4 parts of red mud, 0.5 part of curing agent, 2.3 parts of fly ash and 3.5 parts of ordinary portland cement to pass through a grinding chamber of the mixing device, dispersing some aggregated particles, then entering the mixing chamber of the mixing device, fully and uniformly mixing, then carrying out subsequent spreading and maintenance, and enabling the particles such as broken stones and the like collected by the collecting chamber to be used for spreading of a road surface behind a subsequent roadbed; the water content of the plain soil is 40%.

Example 3

The soil stabilizer is prepared from the following raw materials in parts by weight: 30 parts of sodium carbonate, 20 parts of calcium chloride, 20 parts of calcium sulfate, 40 parts of polymeric ferric sulfate, 8 parts of magnesium oxide, 8 parts of potassium phosphate, 12 parts of modified cellulose, 7 parts of nano zeolite and 8 parts of repair microcapsule;

preparing the modified cellulose: (1) FeCl is added₃·6H₂07 g and FeS0₄·7H₂Dissolving 06 g of the aqueous solution in 120mL of deionized water, heating in a water bath at 80 ℃ for 5min, then dropwise adding 17mL of ammonia water, stirring at 800rpm for 30min, finally performing magnetic separation on the product, and washing with distilled water until the pH is =6 to obtain ferroferric oxide magnetic nanoparticles; (2) mixing celluloseDissolving 7.2g of sodium sulfate, 4.5g of corn starch, 10.2g of polyacrylonitrile and 6.5g of alpha-cyclodextrin in a mixed solution of 60mL of distilled water and 40mL of DMF (dimethyl formamide), stirring for 45min at 500rpm, then adding 1.6g of ferroferric oxide magnetic nanoparticles, dropwise adding 6mL of 30% polyethyleneimine water solution, stirring for 60min at 800rpm, dropwise adding 22mL of 3.0% glutaraldehyde solution, continuously stirring for 4h at 60 ℃, cooling to room temperature, carrying out vacuum filtration, repeatedly washing with distilled water until the pH is =6, drying at 60 ℃, grinding and sieving with a 200-mesh sieve to obtain modified fibers;

the preparation of the repair microcapsule comprises the following steps: (1) adding 4.8g of gelatin into 120mL of distilled water at room temperature, stirring at 1000rpm for 30min, then sequentially adding 4.5g of urea, 5.0g of ammonium chloride and 4.5g of resorcinol, continuing stirring for 30min, and then adjusting the pH of the mixed solution to 3.0 to obtain an emulsifier mixed solution; (2) n is a radical of₂Under the environment, uniformly stirring 7.8g of hexamethylene diisocyanate, 7.3g of isophorone diisocyanate and 8mL of ethyl acetate, slowly adding an emulsifier mixed solution, emulsifying for 20min at 1100r/min, finally adding 12mL of formaldehyde solution with the mass fraction of 37%, reacting for 4h at 55 ℃, cooling to room temperature, filtering, washing a filter cake, and airing at room temperature to obtain a repair capsule with the particle size of 80-100 um;

the use method of the soil stabilizer comprises the following steps: 97 parts of plain soil are added into a screening chamber of a mixing device in batches, grading screening is carried out, large-particle impurities such as broken stones are screened out to a collecting chamber of the mixing device, the screened plain soil enters a mixing chamber, 5 parts of red mud, 1 part of curing agent, 2.5 parts of fly ash and 5 parts of ordinary portland cement sequentially pass through a grinding chamber of the mixing device, some gathered particles are dispersed and then enter the mixing chamber of the mixing device, after the mixture is fully and uniformly mixed, subsequent spreading and maintenance are carried out, and the particles such as broken stones collected by the collecting chamber are used for spreading of a subsequent road surface behind a roadbed; the water content of the plain soil is 60%.

Comparative example 1

The preparation process was substantially the same as that of example 1, except that modified cellulose was absent in the raw materials for preparing the soil stabilizer.

Comparative example 2

The preparation process was substantially the same as that of example 1, except that the nano zeolite was absent from the raw materials for preparing the soil stabilizer.

Comparative example 3

The preparation process was substantially the same as that of example 1, except that the raw materials for preparing the soil stabilizer lacked the repairing microcapsules.

Comparative example 4

The preparation process was substantially the same as that of example 1, except that potassium phosphate and magnesium oxide were absent from the raw materials for preparing the soil stabilizer.

Comparative example 5

The procedure of example 1 was followed except that red mud was absent from the raw materials used in combination with the soil conditioner.

Test example 1

Taking the soil solidified by the curing agents of the examples 1-3 and the comparative examples 1-4 to prepare cylindrical test pieces with the diameter (50mm) multiplied by the height (50mm), carrying out static pressure forming by using a jack, putting the test pieces into a standard curing box for curing to a corresponding age, taking out the test pieces and airing the test pieces to test the compression resistance of the solidified soil, wherein the test results are shown in the table 1:

from table 1, it can be seen that the modified fiber, the nano zeolite, the red mud, the remediation capsule, the potassium phosphate and the magnesium oxide can all increase the compressive strength of soil solidification, the nano zeolite, the red mud, the potassium phosphate and the magnesium oxide have a large influence on the soil solidification, the maximum dry density after solidification is increased, and the modified fiber and the red mud are main components affecting the water absorption rate of the soaking water.

Test example 2 the soil cured by the curing agents of examples 1 to 3 and comparative examples 1 to 4 was used as a road filler for simulation construction, and the road filler for simulation construction was subjected to an anti-scour test according to test regulation for inorganic binder stabilizing materials for road engineering (JTG) T0860-2009, the results of which are shown in table 2:

as can be seen from Table 2, after the soil treated by the soil solidifying agent of the invention is washed, the mass loss rate of the soil solidifying agent of the examples 1-3 is obviously lower than that of the soil treated by the comparative examples 1, 4 and 5, which shows that the soil solidifying agent of the examples 1-3 has better washing resistance, and the solidifying agent is uniformly dispersed in the soil to form a gel network structure under the combined action of the modified fiber, the zeolite, the cement/fly ash/red mud, the potassium phosphate and the magnesium oxide, so that the soil has stronger permeability resistance and water resistance.

Test example 3

The soil solidified by the firming agents of the examples 1 to 3 and the comparative examples 1 to 4 is subjected to a dry-wet cycle test and a freeze-thaw cycle test, wherein the dry-wet cycle test comprises the following steps: selecting solidified soil with age of 7d, drying in an oven at 70 ℃ for 24h, then placing in a water bath for 24h, setting the temperature to be (22 +/-1) DEG C, wherein the process is a dry-wet cycle process, namely 2 days, a dry-wet cycle period, and repeating for 10 times; freeze-thaw cycle testing: selecting solidified soil with age of 28d, freezing for 16h at-18 ℃ in one freeze-thaw cycle, then melting for 8h in a dissolving water tank at (20 +/-1) DEG C to ensure that the water surface is 2cm higher than the test piece, and carrying out freeze-thaw cycle for 10 times, and after the experiment is finished, detecting the compressive strength of the solidified soil, wherein the results are shown in Table 3:

as can be seen from Table 3, the soil firming agents of examples 1-3 have better dry-wet cycle resistance and freeze-thaw resistance, i.e., better durability, while the durability of comparative example 1 is much weaker, and the infinite lateral pressure resistance, dry-wet cycle resistance and freeze-thaw resistance of comparative examples 2-5 are less than those of example 1, indicating that the addition of the modified fiber enhances the adhesion between soils when the soil firming agent is used for soil solidification, and the samples solidified by the firming agent can be maintained for a longer time.

Test example 4

The method comprises the following steps of determining the concentration of metal ions in soil leachate by referring to a horizontal oscillation method (HJ557-2010) for leaching toxicity of solid wastes, investigating the immobilization effect of a curing agent on arsenic and antimony heavy metal ions, wherein the ratio of the leaching concentration of the heavy metal ions in the cured soil to the leaching concentration of the heavy metal ions in the soil before curing (after impurity removal) is the heavy metal curing degree, crushing the cured soil, collecting the modified fiber loaded with ferroferric oxide by using a magnet, detecting the leaching concentration of the heavy metal ions in the crushed soil again, and calculating the recovery rate of the heavy metal, wherein the test results are shown in Table 4:

as can be seen from the comparative example 1 in the table 4, the doping of the modified fiber greatly improves the complexing and curing effect of the soil curing agent on the heavy metal ions in the soil, and the doping of the red mud can be seen in the comparative example 5, so that the cement/fly ash/red mud synergistic effect is realized, the curing of the heavy metal ions in the soil is increased, and the leaching rate of the heavy metal ions is reduced.

Test example 5

The soil solidified by the curing agent of examples 1 to 3 and comparative example 3 was subjected to pressure application so that the solidified soil was slightly cracked, and then divided into two parts, followed by curing for 7d,

taking the soil cured by the curing agents of the examples 1-3 and the comparative example 3, preparing two groups of cylindrical test pieces with the same diameter (50mm) multiplied by height (50mm), carrying out static pressure forming by using a jack, putting the cylindrical test pieces into a standard curing box for curing to a corresponding age, taking out and airing, applying pressure to cause the cured soil to have slight cracks, carrying out water immersion and water absorption detection on one group, carrying out water immersion and water absorption detection on the other group after curing for 7 days, wherein the detection results are shown in table 5:

from table 5, it can be seen that the soil curing agent doped with the repair capsule can react the exuded isocyanate repair liquid with water after the cured soil has cracks, and then cross-linked and cured with the modified fiber, so that the soil can be repaired by itself.

While the invention has been described in further detail with reference to specific embodiments thereof, it is not intended that the invention be limited to the specific embodiments thereof; for those skilled in the art to which the present invention pertains and related technologies, the extension, operation method and data replacement should fall within the protection scope of the present invention based on the technical solution of the present invention.

Claims

1. a soil solidifying agent, is characterized in that, is prepared from the raw material of following parts by weight: 20-30 parts of sodium carbonate, 15-20 parts of calcium chloride, 15-20 parts of calcium sulfate, 30-20 parts of polyferric sulfate 40 parts, 5-8 parts of magnesium oxide, 5-8 parts of potassium phosphate, 10-12 parts of modified cellulose, 5-7 parts of nano-zeolite, 6-8 parts of repair microcapsules;

Preparation of the modified cellulose: (1) Dissolve FeCl ₃ ·6H ₂ 0 and FeS0 ₄ ·7H ₂ 0 in deionized water, heat in a water bath at 70-80°C for 3-5min, add ammonia water dropwise, 600- Stir at 800rpm for 20-30min, and finally the product is subjected to magnetic separation, washed with distilled water to PH=5-6, to obtain ferric oxide magnetic nanoparticles; (2) cellulose sodium sulfate, corn starch, polyacrylonitrile, α- The cyclodextrin was dissolved in the mixture of distilled water and DMF, stirred at 400-500rpm for 30-45min, then added ferric oxide magnetic nanoparticles, and added dropwise the polyethyleneimine aqueous solution, stirred at 600-800rpm for 45-60min, and then dripped Add glutaraldehyde solution, continue stirring at 45-60 ℃ for 3-4 hours, then cool to room temperature, then carry out vacuum filtration, and repeatedly wash with distilled water to PH=5-6, dry at 45-60 ℃, grind 100-200 mesh sieve to obtain modified fibers;

The preparation of the repairing microcapsules: (1) at room temperature, add gelatin to distilled water, stir at 800-1000rpm for 20-30min, then add urea, ammonium chloride and resorcinol in sequence, continue to stir for 20-30min, then Adjust the pH of the mixture to 3.0 to obtain an emulsifier mixture; (2) under N ₂ environment, stir hexamethylene diisocyanate, isophorone diisocyanate and ethyl acetate evenly, then slowly add the emulsifier mixture, Emulsify at 1000-1100r/min for 10-20min, finally add 37% formaldehyde solution, react at 50-55°C for 3-4h, cool to room temperature, filter, wash the filter cake, air dry at room temperature to obtain 80- 100um repair capsule;

The preparation of the soil solidifying agent: the modified cellulose, the repaired microcapsules, and the nano-zeolite are mixed uniformly, and then sodium carbonate, calcium chloride, calcium sulfate, polymerized ferric sulfate, magnesium oxide, and potassium phosphate are added and mixed uniformly again;

The use method of the soil curing agent is as follows: 95-97 parts of plain soil are added in batches to the screening chamber of the mixing device, grading and sieving are carried out, and large particles of impurities such as crushed stones are screened out to the collection chamber of the mixing device, and sieving is carried out. The pasted plain soil enters the mixing chamber, and then 3-5 parts of red mud, 0.05-1 part of curing agent, 2-2.5 parts of fly ash, and 2-5 parts of ordinary Portland cement are passed through the grinding chamber of the mixing device in turn. Then enter the mixing chamber of the mixing device, fully mix evenly, and then carry out subsequent spreading and maintenance.

2. The preparation system of a soil solidifying agent according to claim 1, wherein in the preparation step (1) of the modified cellulose, FeCl ₃ .6H ₂ 0:FeSO ₄ .7H ₂ 0: The mass volume ratio of deionized water: ammonia water is: 6-7g:4-6g:100-120mL:15-17mL.

3. The preparation system of a soil curing agent according to claim 1, wherein in the preparation step (2) of the modified cellulose, sodium cellulose sulfate: corn starch: polyacrylonitrile: α-ring The mass volume ratio of dextrin: distilled water: DMF: ferric oxide magnetic nanoparticles: polyethyleneimine aqueous solution: glutaraldehyde solution: 6.8-7.2g:4.3-4.5g:8.8-10.2g:5.5-6.5g : 50-60mL: 30-40mL: 1.2-1.6g: 5-6mL: 20-22mL.

4. The preparation system of a soil curing agent according to claim 1, wherein the mass fraction of polyethyleneimine in the polyethyleneimine aqueous solution is 30%; the mass fraction of glutaraldehyde solution The mass fraction is 3.0%.

5. the preparation system of a kind of soil solidifying agent according to claim 1, is characterized in that, in the preparation of described repairing microcapsules: gelatin: distilled water: urea: ammonium chloride: resorcinol: hexamethylene diamine The mass volume ratio of isocyanate:isophorone diisocyanate:ethyl acetate:formaldehyde is: 2.4-4.8g:100-120mL:3.2-4.5g:4.4-5.0g:4.2-4.5g:7.2-7.8g:6.6 -7.3g: 6-8mL: 10-12mL.

6. The preparation system of a soil curing agent according to claim 1, wherein the moisture content of the plain soil is 20-60%.

7 . The preparation system of a soil curing agent according to claim 1 , wherein the mixing device comprises a screening chamber, a collection chamber, a mixing chamber and a grinding chamber; the screening chamber comprises a screening chamber shell. 8 . The upper and lower sieving membranes are arranged on the body and the sieving chamber shell. The upper sieving membrane does not allow the passage of gravel particles, and the lower sieving membrane only allows soil-sized particles to pass through. The upper and lower sieving membranes are above the All are equipped with telescopic harrows. The telescopic harrow above the upper screening membrane moves the gravel particles into the collection chamber on the right of the upper screening membrane, and at the same time presses the soil onto the lower screening membrane. The telescopic harrow above the lower screening membrane will be larger than The impurities of the soil particles are moved into the collection chamber on the right of the lower sieving membrane, and the soil is squeezed through the lower sieving membrane at the same time. There are inclined baffles under the upper and lower sieving membranes, and the bottom of the sieving chamber is connected to the upper part of the mixing chamber. The upper part of the mixing chamber is connected to the bottom of the grinding chamber, the mixing chamber is provided with a mixing structure, and the bottom of the mixing chamber is provided with an outlet; the grinding chamber includes a bucket-shaped grinding shell, and the top of the bucket-shaped grinding shell is provided with a material inlet and a motor, and the motor The machine shaft faces down and is connected with a grinding disc. The grinding disc is located above the bottom of the bucket-shaped grinding shell. The bottom of the bucket-shaped grinding shell is a grid plate. The relative movement of the grinding disc and the grid plate squeezes the large particles of the added material. dispersion.