Novel soil stabilizer and preparation and use method thereof

Abstract

The invention belongs to the technical field of soil solidification, and particularly relates to a novel soil solidifying agent and a preparation and use method thereof. The novel soil stabilizer is prepared from the following components in parts by mass: 15 to 25 parts of basic curing agent, 0.2 to 1 part of polyacrylamide, 0.5 to 1 part of polypropylene fiber and 0.1 to 0.5 part of nano silicon dioxide, the soil stabilizer disclosed by the invention takes lime and cement as main raw materials, the price is low, the cost performance is high, and nano silicon dioxide can be used for filling tiny pores in soil, so that the strength of the solidified soil is improved; according to the invention, the nano-silica, the polyacrylamide and the polypropylene fiber are compounded according to a proper ratio, and the components have a synergistic effect, so that the curing effect of the cement in the basic curing agent is improved, the curing time of the soil is shortened, and the overall construction cost is reduced; the comprehensive performance of the solidified soil can be obviously improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil solidification, and specifically relates to a novel soil solidifying agent and its preparation and use methods. Background Art

[0002] A soil solidifying agent is an engineering material used to solidify various types of soil. It is widely used in road construction, land restoration, agricultural production, and other civil engineering fields. The soil solidifying agent reacts with water, minerals, and organic matter in the soil to form a solid structure, improving the physical and mechanical properties of the soil, enhancing the bearing capacity of the soil, reducing its expansibility and fluidity, thereby increasing the strength, stability, compressive capacity, and water erosion resistance of the soil, and improving the safety and durability of the project.

[0003] Currently, the soil solidifying agents used in engineering mainly utilize external industrial waste residues such as cement and lime and alkaline activators to solidify the soil. On the one hand, traditional inorganic solidifying agents such as cement and lime rely on hydration reactions to generate cementitious substances, but the strength development of cement hydration takes 28 days to complete, and the carbonation reaction of quicklime takes several months to stabilize, resulting in the need for a long-term curing period in the project. Industrial waste residues (such as fly ash and steel slag) need to be pre-ground to the micron level (specific surface area > 300 m 2 / kg) to activate their activity, and multiple mixing and layered compaction are required (such as lime soil needs to be rolled 6 - 8 times), which also significantly increases the working hours. On the other hand, traditional solidified soil types such as cement soil and lime soil have higher porosity and looseness, and at the same time exhibit significant brittle deformation characteristics, and cannot form a relatively complex cementitious structure inside the soil body, resulting in insufficient strength and poor toughness. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a novel soil solidifying agent and a method for preparing solidified soil using the same. By using the soil solidifying agent proposed by the present invention, the soil can be quickly solidified, significantly shortening the construction period of the project, reducing the overall construction cost, and having little impact on the environment, meeting the requirements of green building and sustainable development. By using the soil solidifying agent proposed by the present invention, the soil body can also balance strength and toughness, with high safety and good durability.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a novel soil solidifying agent, which is composed of the following components in parts by mass: 15 parts to 25 parts of a basic solidifying agent, 0.2 parts to 1 part of polyacrylamide, 0.5 parts to 1 part of polypropylene fiber, and 0.1 parts to 0.5 parts of nano-silica.

[0007] Specifically, the polyacrylamide is cationic with a molecular weight of 16 million to 23 million.

[0008] Specifically, the base curing agent is cement or a mixture of cement and lime.

[0009] Specifically, in the mixture of cement and lime, the mass ratio of cement to lime is (2 - 3):(1 - 2).

[0010] Specifically, the length of the polypropylene fiber is 10 mm - 14 mm, and the diameter is 18 μm - 48 μm.

[0011] Specifically, the diameter of the nano - silica is 25 nm - 35 nm.

[0012] Specifically, it includes the following steps:

[0013] S1. Mix the base curing agent, polyacrylamide, and polypropylene fiber to obtain a mixture.

[0014] S2. Screen the mixture, and uniformly mix the material passing through the sieve with the mixture obtained in S1 to obtain the soil curing agent.

[0015] The present invention also provides a method for using the novel soil curing agent, which includes the following steps:

[0016] s1. Collect the soil to be cured.

[0017] s2. Dry the soil to be cured and then screen it to obtain small - particle soil.

[0018] s3. Uniformly mix the soil curing agent and the small - particle soil obtained in s2 to obtain the first mixed soil.

[0019] s4. Add water to the first mixed soil obtained in s3 and stir evenly to obtain the second mixed soil.

[0020] s5. First, compact the second mixed soil obtained in s4, and then cure it to obtain the cured soil.

[0021] Specifically, in s3, the mass ratio of the small - particle soil to the soil curing agent is (3 - 7):(0.5 - 1.2).

[0022] Specifically, in s4, the mass ratio of the first mixed soil to water is (41 - 42):(8 - 9).

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] (1) The soil stabilizer of the present invention uses lime and cement as the main raw materials, with low price and high cost performance. Due to its high specific surface area and unique chemical properties, nano-silica can not only fill the tiny pores in the soil, enhance the structural compactness of the basic stabilizer, and improve the strength of the solidified soil, but also serve as a nucleation site for the hydration reaction, accelerate the hydration reaction of cement in the basic stabilizer, promote the formation of C-S-H gel, shorten the solidification time of the soil, and reduce the overall construction cost.

[0025] (2) In the present invention, the amide groups on the polyacrylamide molecular chain can form hydrogen bond binding with the hydroxyl groups on the surface of polypropylene fibers, improving the binding force between the fibers. When the polyacrylamide molecular chain winds around the surface of polypropylene fibers, it can fill the gaps between the polypropylene fibers and further tighten the connection between the fibers through the contraction of the molecular chain during the soil solidification process, ensuring the compactness between the soil bodies, improving the toughness and strength of the soil bodies, and enhancing the safety and durability of the soil bodies. In addition, the polypropylene fibers are negatively charged. If the polyacrylamide is cationic, the polypropylene fibers can also adsorb with the cationic groups of the polyacrylamide to form larger flocs, further strengthening the connection inside the soil body and improving the strength and toughness of the solidified soil.

[0026] (3) In the present invention, nano-silica is dispersed in the soil body to form a good interfacial bond with polypropylene fibers, which can increase the molecular chain movement resistance of polypropylene fibers, effectively prevent the slippage of the polypropylene fiber molecular chain in the solidified soil, and thus improve the mechanical properties of the solidified soil.

[0027] (4) The polyacrylamide of the present invention has water retention and is an excellent chelating agent. The surface of the polyacrylamide adsorbs polypropylene fibers and nano-silica particles, which can significantly reduce the permeability coefficient of the solidified soil. While increasing the strength of the solidified soil, lime can also adjust the pH of the solidified soil, enhance the chelating ability of polyacrylamide for Pb 2 +, Cd 2 +, and significantly reduce the leaching of heavy metal ions such as Pb 2 +, Cd 2 +. In addition, the present invention does not contain acidic substances, which can significantly improve the impact of the solidified soil on the environment.

[0028] (5) In the present invention, polyacrylamide can adsorb nano-silica, enhancing the steric hindrance between nano-silica particles and enabling the uniform dispersion of nano-silica in the soil matrix. However, if the content of polyacrylamide is too high, it will instead cause the aggregation of nano-silica, leading to a decline in the comprehensive performance of the solidified soil; if the content of nano-silica is too high, a large number of nano-scale pores will be generated inside the polypropylene fiber, which will also reduce the comprehensive performance of the solidified soil. The present invention rationalizes the ratio of the basic curing agent, nano-silica, polyacrylamide, and polypropylene fiber, improving the comprehensive performance of the solidified soil while ensuring the uniformity of the solidified soil and its stability in the later stage. Detailed implementation manners

[0029] The following will describe clearly and completely the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0030] Embodiment 1

[0031] The novel soil curing agent of this embodiment is composed of the following components in parts by mass:

[0032] 10 parts of cement, 5 parts of lime, 0.2 part of polyacrylamide, 1 part of polypropylene fiber, and 0.1 part of nano-silica.

[0033] The polyacrylamide is cationic with a molecular weight of 16 million.

[0034] The length is 10 mm and the diameter is 18 μm.

[0035] The diameter of the nano-silica is 25 nm.

[0036] The preparation method of the novel soil curing agent of this embodiment includes the following steps:

[0037] S1. Mix the basic curing agent, polyacrylamide, and polypropylene fiber to obtain a mixture.

[0038] S2. Screen the mixture, and uniformly mix the material passing through the screen with the mixture obtained in S1 to obtain the soil curing agent.

[0039] The usage method of the novel soil curing agent prepared in this embodiment includes the following steps:

[0040] s1. Collect the soil to be solidified.

[0041] s2. Dry the soil to be solidified and then screen it to obtain small-particle soil.

[0042] S3. Mix the soil stabilizer and the small particle soil obtained in S2 evenly to obtain the first mixed soil. In the first mixed soil, the mass ratio of the small particle soil to the soil stabilizer is 6:1.

[0043] S4. Add water to the first mixed soil obtained in S3 and stir evenly to obtain the second mixed soil. In the second mixed soil, the mass ratio of the first mixed soil to water is 41:8.

[0044] S5. First compact the second mixed soil obtained in S4, and then cure it to obtain the solidified soil.

[0045] Example 2

[0046] The novel soil stabilizer of this example is composed of the following components in parts by mass:

[0047] 9 parts of cement, 9 parts of lime, 0.5 part of polyacrylamide, 0.8 part of polypropylene fiber, and 0.2 part of nano-silica.

[0048] The polyacrylamide is cationic with a molecular weight of 18 million.

[0049] The length is 11 mm and the diameter is 28 μm.

[0050] The diameter of the nano-silica is 27 nm.

[0051] The preparation method of the novel soil stabilizer of this example includes the following steps:

[0052] S1. Mix the basic stabilizer, polyacrylamide, and polypropylene fiber to obtain a mixture.

[0053] S2. Screen the mixture, and evenly mix the undersize with the mixture obtained in S1 to obtain the soil stabilizer.

[0054] The usage method of the novel soil stabilizer prepared in this example includes the following steps:

[0055] S1. Collect the soil to be solidified.

[0056] S2. Dry the soil to be solidified and then screen it to obtain small particle soil.

[0057] S3. Mix the soil stabilizer and the small particle soil obtained in S2 evenly to obtain the first mixed soil. In the first mixed soil, the mass ratio of the small particle soil to the soil stabilizer is 7:1.2.

[0058] S4. Add water to the first mixed soil obtained in S3 and stir evenly to obtain the second mixed soil. In the second mixed soil, the mass ratio of the first mixed soil to water is 41.5:8.5.

[0059] S5. First, compact the second mixed soil obtained in S4, and then cure it to obtain the solidified soil.

[0060] Example 3

[0061] The novel soil stabilizer of this example is composed of the following components in parts by mass:

[0062] 21 parts of cement, 0.8 part of polyacrylamide, 0.6 part of polypropylene fiber, 0.4 part of nano-silica.

[0063] The polyacrylamide is cationic with a molecular weight of 21 million.

[0064] The length is 12 mm and the diameter is 38 μm.

[0065] The diameter of the nano-silica is 32 nm. [[ID=2Y]]

[0066] The preparation method of the novel soil stabilizer of this example includes the following steps:

[0067] S1. Mix the base stabilizer, polyacrylamide, and polypropylene fiber to obtain a mixture.

[0068] S2. Screen the mixture, and uniformly mix the undersize with the mixture obtained in S1 to obtain the soil stabilizer.

[0069] The usage method of the novel soil stabilizer prepared in this example includes the following steps:

[0070] s1. Collect the soil to be solidified.

[0071] s2. Dry the soil to be solidified and then screen it to obtain small particle soil.

[0072] s3. Uniformly mix the soil stabilizer and the small particle soil obtained in s2 to obtain the first mixed soil; in the first mixed soil, the mass ratio of the soil stabilizer to the small particle soil is 4:0.7.

[0073] s4. Add water to the first mixed soil obtained in s3 and stir evenly to obtain the second mixed soil; in the second mixed soil, the mass ratio of the first mixed soil to water is 42:9.

[0074] s5. First, compact the second mixed soil obtained in s4, and then cure it to obtain the solidified soil.

[0075] Example 4

[0076] The novel soil stabilizer of this example is composed of the following components in parts by mass:

[0077] 18.5 parts of cement, 6.5 parts of lime, 1 part of polyacrylamide, 0.5 part of polypropylene fiber, 0.5 part of nano-silica.

[0078] The polyacrylamide is cationic with a molecular weight of 23 million.

[0079] The length is 14 mm and the diameter is 48 μm.

[0080] The diameter of the nano-silica is 35 nm.

[0081] The preparation method of the novel soil stabilizer in this embodiment includes the following steps:

[0082] S1. Mix the basic stabilizer, polyacrylamide, and polypropylene fiber to obtain a mixture.

[0083] S2. Screen the mixture, and uniformly mix the undersize with the mixture obtained in S1 to obtain the soil stabilizer.

[0084] The usage method of the novel soil stabilizer prepared in this embodiment includes the following steps:

[0085] s1. Collect the soil to be solidified.

[0086] s2. Dry the soil to be solidified and then screen it to obtain small-particle soil.

[0087] s3. Uniformly mix the soil stabilizer and the small-particle soil obtained in s2 to obtain the first mixed soil; in the first mixed soil, the mass ratio of the soil stabilizer to the small-particle soil is 5:1.

[0088] s4. Add water to the first mixed soil obtained in s3 and stir evenly to obtain the second mixed soil; in the second mixed soil, the mass ratio of the first mixed soil to water is 41:9.

[0089] s5. First compact the second mixed soil obtained in s4, and then cure it to obtain the solidified soil.

[0090] In the above embodiments, the screening can be carried out using a square-hole sieve with a pore size of 60 μm to 100 μm.

[0091] Comparative Example 1

[0092] The difference from Example 1 is that it does not contain nano-silica, and the rest is the same as Example 1.

[0093] Comparative Example 2

[0094] The difference from Example 2 is that it does not contain polyacrylamide, and the rest is the same as Example 2.

[0095] Comparative Example 3

[0096] It is different from Example 3 in that it does not contain polypropylene fibers, and the rest is the same as Example 3.

[0097] Comparative Example 4

[0098] Replace the amount of nano-silica in Example 1 with 0.6 parts, and the rest is the same as Example 4.

[0099] Comparative Example 5

[0100] Replace the amount of polypropylene fibers in Example 1 with 0.3 parts, and the rest is the same as Example 1.

[0101] To better understand the excellent performance of the present invention, the solidified soils obtained from Examples 1 to 4 and Comparative Examples 1 to 5 were respectively filled into unconfined compression test molds, and standard cylindrical specimens with a diameter of 50 mm and a height of 50 mm were prepared by the sample pressing method, and demolded with a jack; the prepared specimens were wrapped with fresh-keeping film to prevent water loss, and placed in a constant temperature and humidity curing box (temperature is 20 ± 2 °C, humidity is 95% ± 1%) for curing for 7 d and 14 d. Referring to the requirements of JTGE51-2009 "Test Procedures for Inorganic Binding Material Stabilized Materials in Highway Engineering", the compressive test of the solidified soil was carried out, and referring to GBT50123-2023 "Standard for Geotechnical Test Methods", a vertical pressure of 100 kPa was selected to carry out the shear test on the solidified soil. The test results are as follows in the table:

[0102]

[0103] The specific implementation manners of the present invention enable those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0104] It should be understood that the present invention is not limited to the above-described content, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A novel soil stabilizer, characterized in that, It is composed of the following components by mass parts: 15 parts to 25 parts of a base curing agent, 0.2 parts to 1 part of polyacrylamide, 0.5 parts to 1 part of polypropylene fiber, and 0.1 parts to 0.5 parts of nano-silica.

2. The novel soil stabilizer according to claim 1, wherein The polyacrylamide is cationic and has a molecular weight of 16 million to 23 million.

3. The novel soil stabilizer according to claim 1, characterized in that, The base curing agent is cement or a mixture of cement and lime.

4. The novel soil stabilizer according to claim 3, characterized in that, In the mixture of cement and lime, the mass ratio of cement to lime is (2 to 3):(1 to 2).

5. The novel soil stabilizer according to claim 1, characterized in that, The length of the polypropylene fiber is 10 mm to 14 mm, and the diameter is 18 μm to 48 μm.

6. The novel soil stabilizer according to claim 1, characterized in that, The diameter of the nano-silica is 25 nm to 35 nm.

7. The preparation method of the novel soil stabilizer according to any one of claims 1 to 6, characterized in that, It includes the following steps: S1. Mix the base curing agent, polyacrylamide, and polypropylene fiber to obtain a mixture. S2. Screen the mixture, and uniformly mix the undersize with the mixture obtained in S1 to obtain a soil curing agent.

8. A method for using the novel soil stabilizer according to any one of claims 1 to 6, characterized in that, It includes the following steps: s1. Collect the soil to be cured. s2. Dry the soil to be cured and then screen it to obtain small-particle soil. s3. Uniformly mix the soil curing agent and the small-particle soil obtained in s2 to obtain a first mixed soil. s4. Add water to the first mixed soil obtained in s3 and stir evenly to obtain a second mixed soil. s5. First compact the second mixed soil obtained in s4, and then cure it to obtain a cured soil.

9. The method for using the novel soil stabilizer according to claim 8, wherein, In s3, the mass ratio of the small-particle soil to the soil curing agent is (3 to 7):(0.5 to 1.2).

10. The method for using the novel soil stabilizer according to claim 8, characterized in that, In s4, the mass ratio of the first mixed soil to water is (41 to 42):(8 to 9).

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