Nano-based shield muck improving foaming agent and preparation method and application thereof

Abstract

The invention belongs to the technical field of shield construction, and particularly relates to a nano-based shield muck improving foaming agent as well as a preparation method and application thereof. Specifically, in the field of shield tunneling foaming agents, nano silicon dioxide is innovatively adopted as a powerful foam stabilizer, the powerful foam stabilizer, hydroxypropyl methyl cellulose, polyvinyl alcohol and coconut oil diethanolamide jointly form a powerful foam stabilizing system, and dodecyl dimethyl amine oxide and sodium alpha-olefin sulfonate serve as auxiliary foaming components to expand environmental adaptability. And the muck improved foam with small volume, strong deformability and good stability is formed. Foam prepared by the foaming agent provided by the invention has the advantages of moderate foaming ratio, long half-life period, fine foam, small volume and the like, that is, the foaming agent can continuously and effectively play a role in improving the muck, and can effectively meet the requirements on the performance of the muck in the whole shield construction process, so that the foaming agent has good practical application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of shield construction, and particularly relates to a nano-based shield muck improvement foam agent, a preparation method thereof, and an application thereof. Background Art

[0002] Disclosing the information of this background art section is only intended to increase the understanding of the overall background of the present invention, and is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Under the background of the rapid development of urban rail transit, the shield construction technology, as the core construction method for underground tunnel construction, has been widely applied. It is worth noting that when the shield equipment passes through cohesive soil layers (such as clay and silty clay layers), its operating system often faces severe challenges. Due to the specific viscous characteristics of the fine-grained substances in such strata, it is extremely easy to cause adhesion and accumulation at key parts such as the cutter head system, excavation chamber, and screw soil discharge device. This phenomenon will not only trigger the cutter head mud caking effect, resulting in abnormal torque increase or even equipment jamming, but also cause blockage of the screw conveying channel, and then disrupt the dynamic balance of the pressure field in the excavation chamber, ultimately seriously affecting the shield propulsion efficiency.

[0004] As the core material for soil improvement, although foam agents are widely used in engineering practice, through in-depth research by the inventor, it is found that existing products still have significant technical defects. Specifically, the foaming system has defects such as uneven bubble diameter distribution and loose bubble structure, resulting in insufficient dispersion uniformity of the modifier in the muck; particularly prominent is that the existing foam stability index does not meet the standard, and there is a significant gap between the liquid phase maintenance time and the construction period. When the foam is mixed with the muck, due to the too short foam holding time, a continuous and effective lubricating isolation layer cannot be formed, resulting in the rapid attenuation of the soil improvement effect with the construction process, and thus it is difficult to meet the strict requirements of the full-cycle shield tunneling for the flow plasticity of the muck. Summary of the Invention

[0005] Aiming at the deficiencies of the above-mentioned existing technologies, the purpose of the present invention is to provide a nano-based shield muck improvement foam agent, a preparation method thereof, and an application thereof. Specifically, through the synergistic action of multiple components, the present invention can significantly improve the foaming performance and foam stability, ensure that the generated foam is delicate, uniform, and long-lasting and stable, thereby effectively improving the performance of the shield muck and providing a solid guarantee for the efficient and stable tunneling of the shield machine. Based on the above research results, the present invention is completed.

[0006] In order to achieve the above technical objectives, the technical solutions provided by the present invention are as follows:

[0007] In the first aspect of the present invention, a nano-based shield muck improvement foam agent is provided, which is composed of the following components by weight: 2.1 - 2.7 parts of sodium dodecyl sulfate, 0.7 - 0.9 parts of dodecyldimethylamine oxide, 1.2 - 2.4 parts of α-olefin sulfonate, 1 - 2.5 parts of N,N-dimethylacetamide, 0.05 - 0.1 parts of hydroxypropyl methylcellulose, 0.2 - 0.5 parts of nano-silica, 1 - 2 parts of coconut oil diethanolamide, 2 - 4 parts of polyvinyl alcohol, and 120 - 150 parts of water.

[0008] In the second aspect of the present invention, a preparation method of the above nano-based shield muck improvement foam agent is provided, and the preparation method includes:

[0009] S1: After uniformly mixing water and N,N-dimethylacetamide, then successively adding nano-silica, coconut oil diethanolamide, polyvinyl alcohol, dodecyldimethylamine oxide, α-olefin sulfonate, and sodium dodecyl sulfate thereto;

[0010] S2: Heating to 50 - 60 °C, adding hydroxypropyl methylcellulose to the mixed solution in step S1, and naturally cooling to room temperature.

[0011] In the third aspect of the present invention, an application of the above nano-based shield muck improvement foam agent in muck improvement is provided.

[0012] Further, the application environment is specifically a shield construction environment.

[0013] The beneficial technical effects of the above one or more technical solutions:

[0014] In the field of shield foam agents, the above technical solution innovatively uses nano-silica as a powerful foam stabilizer, which together with hydroxypropyl methylcellulose, polyvinyl alcohol, and coconut oil diethanolamide forms a powerful foam stabilizer system, and uses dodecyldimethylamine oxide and α-olefin sulfonate as auxiliary foaming components to expand the environmental adaptability, forming a muck improvement foam with small volume, strong deformation ability, and good stability.

[0015] The foam prepared by the foam agent provided by the above technical solution has the following advantages: the foaming ratio is 20 - 30 times, the half-life is 30 - 40 min, and the overall average radius is 100 - 200 μm. It has the advantages of moderate foaming ratio, long half-life, fine and small foam volume, etc., that is, the foam agent can continuously and effectively play the role of improving muck, can effectively meet the requirements of muck performance during the whole process of shield construction, and therefore has good practical application value. Specific embodiments

[0016] It should be noted that the following detailed description is illustrative and aims to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains.

[0017] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0018] As mentioned above, as a key material for muck improvement, foam agents are widely used in shield tunneling construction. However, the foams produced by common foam agents currently are often not fine and dense enough, and their volume uniformity is poor, making it difficult to achieve uniform dispersion in muck, resulting in uneven muck improvement effects. Moreover, the stability of the foam is poor and the half-life is too short. A large number of bubbles will burst soon after being mixed with muck, and it cannot continuously and effectively play the role of improving muck.

[0019] In view of this, in a typical specific embodiment of the present invention, a nano-based shield muck improvement foam agent is provided. By weight, it is composed of the following components: 2.1 - 2.7 parts of sodium dodecyl sulfate, 0.7 - 0.9 parts of dodecyldimethylamine oxide, 1.2 - 2.4 parts of α-olefin sulfonate, 1 - 2.5 parts of N,N-dimethylacetamide, 0.05 - 0.1 part of hydroxypropyl methylcellulose, 0.2 - 0.5 part of nano-silica, 1 - 2 parts of coconut oil diethanolamide, 2 - 4 parts of polyvinyl alcohol, and 120 - 150 parts of water.

[0020] Among them, sodium dodecyl sulfate, as the main foaming agent, can effectively reduce the surface tension in the solution by virtue of its good surface activity, promoting the generation of a large number of bubbles.

[0021] Dodecyldimethylamine oxide, as a foam stabilizer, forms a mixed micelle with sodium dodecyl sulfate synergistically, enhancing the surface viscoelasticity of the liquid film; stabilizing the foam structure through electrostatic action and inhibiting the coalescence of bubbles. It can effectively enhance the stability and uniformity of the bubbles, make the generated foam structure more stable, and strongly reduce the possibility of foam rupture, prolonging the survival time of the foam in muck.

[0022] α-olefin sulfonate, as an auxiliary foaming agent, can make up for the performance loss of sodium dodecyl sulfate in hard water, enhance the salt tolerance of the foam and geological adaptability, and adapt to complex hydrogeological environments.

[0023] Coconut oil diethanolamide and hydroxypropyl methylcellulose are used as thickening and foam stabilizing agents. Among them, hydroxypropyl methylcellulose can significantly increase the viscosity of the foam solution, effectively slow down the drainage rate of the foam, and strengthen the strength and toughness of the foam liquid film; coconut oil diethanolamide can be compounded with anionic surfactants to form a dense adsorption layer, while reducing the surface tension gradient of the liquid film to inhibit the rupture caused by the Marangoni effect.

[0024] Nano-silica powder, as a powerful foam stabilizing agent, due to its unique nano-size effect and large specific surface area, can tightly adsorb on the surface of the foam liquid film, effectively fill the weak parts of the liquid film, enhance the anti-deformation ability of the liquid film, and greatly improve the stability of the foam.

[0025] Polyvinyl alcohol is used as an auxiliary foam stabilizing agent, which can form a flexible polymer film on the surface of the liquid film to enhance the anti-mechanical disturbance ability; in cooperation with nano-silica, it constructs a "rigid-flexible combination" composite film structure to further improve the coordinated deformation ability of the foam.

[0026] N,N-dimethylacetamide is used as a dissolution synergist to promote dispersion, and at the same time can adjust the system polarity and enhance the orderly arrangement of surfactant molecules.

[0027] Water is used as a solvent to provide a uniform dispersion medium environment for each component, ensure the full dissolution and mixing of each component, realize the synergistic effect, and ensure the stable performance of the foaming agent.

[0028] The synergistic effect of the above components is as follows:

[0029] This nano-modified shield muck improvement foaming agent constructs a four-in-one high-efficiency system of "foaming-stabilizing foam-anti-interference-structure strengthening" through the synergistic effect of multiple components: the main foaming agent sodium dodecyl sulfate and the auxiliary foaming agent α-olefin sulfonate form a complementarity. The former realizes rapid foaming by virtue of strong surface activity, and the latter improves the salt tolerance through the steric hindrance effect of the sulfonic acid group. Combined with the regulation of the system polarity by N,N-dimethylacetamide, the arrangement of surfactant molecules is optimized, and the foaming efficiency and adaptability to water quality fluctuations are significantly enhanced; in terms of liquid film stability, dodecyldimethylamine oxide and the main foaming agent form mixed micelles through electrostatic interlocking, significantly increasing the viscoelastic modulus of the liquid film. Nano-silica constructs a dense network through interface anchoring to inhibit Ostwald ripening. At the same time, hydroxypropyl methylcellulose and coconut oil diethanolamide synergistically thicken to form a shear-thinning fluid, and the half-life is significantly extended compared with the conventional system; for the complex formation environment, the components form a pH buffer and a gel-like structure through dynamic hydrogen bond recombination, combined with the metal ion tolerance characteristics of α-olefin sulfonate, to achieve stable efficacy in an ionic environment; in addition, the hydrophobic chain segment of coconut oil diethanolamide associates with nanoparticles, and the micro-rupture of the liquid film is autonomously repaired through the Marangoni effect, and the synergistic long-chain entanglement of HPMC further extends the foam half-life.

[0030] In another specific embodiment of the present invention, the sodium dodecyl sulfate, sodium α-olefin sulfonate, and dodecyldimethylamine oxide are all of analytical purity.

[0031] In another specific embodiment of the present invention, the nano-silica has a particle size of 30 - 50 nm. Further, the nano-silica is hydrophobic nano-silica.

[0032] In another specific embodiment of the present invention, a preparation method of the above nano-based shield muck improvement foam agent is provided. The preparation method includes:

[0033] S1: After uniformly mixing water and N,N-dimethylacetamide, successively add nano-silica, coconut oil diethanolamide, polyvinyl alcohol, dodecyldimethylamine oxide, sodium α-olefin sulfonate, and sodium dodecyl sulfate thereto;

[0034] S2: Heat to 50 - 60 °C, and add hydroxypropyl methylcellulose to the mixed solution in step S1, and then naturally cool to room temperature.

[0035] In steps S1 and S2, in order to fully mix the component raw materials, stirring treatment is performed when adding the component raw materials.

[0036] In step S1, water and N,N-dimethylacetamide are mixed evenly at medium speed;

[0037] When adding the nano-silica, coconut oil diethanolamide, and polyvinyl alcohol, they are all mixed evenly at high speed;

[0038] When adding the dodecyldimethylamine oxide, it is mixed evenly at medium speed, and after the addition, keep stirring at medium speed for 1 - 2 min;

[0039] When adding the sodium α-olefin sulfonate and sodium dodecyl sulfate, they are mixed evenly at low speed.

[0040] In step S2, when adding the hydroxypropyl methylcellulose, it is mixed evenly at low speed, and after the addition, continue to keep stirring at low speed for 5 - 10 min.

[0041] In another specific embodiment of the present invention, the low-speed stirring speed range is 50 - 100 r / min; the medium-speed stirring speed range is 150 - 300 r / min; the high-speed stirring speed range is 450 - 600 r / min.

[0042] In another specific embodiment of the present invention, in order to ensure that the component raw materials are more evenly mixed when added, a slow addition method is adopted when adding each component raw material.

[0043] In yet another specific embodiment of the present invention, there is provided an application of the above-mentioned nano-based shield muck improvement foam agent in muck improvement.

[0044] In yet another specific embodiment of the present invention, the application environment is specifically a shield construction environment.

[0045] The present invention will be further described below with reference to embodiments. The present invention will be further illustrated by way of examples below, but the present invention is not limited to the scope of the described embodiments. Based on the embodiments of the present invention, any changes to the present invention made by those skilled in the art without creative efforts fall within the protection scope of the present invention. At the same time, in the embodiments of the present invention, unless otherwise specified, all preparation raw materials are commercially available products well known to those skilled in the art. Unless otherwise specified, the nano-silica in the embodiments and comparative examples of the present invention is hydrophobic nano-silica with a particle size of 40 nm.

[0046] Example 1

[0047] Sodium dodecyl sulfate: 2.4 parts, dodecyldimethylamine oxide: 0.8 part, α-olefin sulfonate: 1.8 parts, N,N-dimethylacetamide: 1.75 parts, hydroxypropyl methylcellulose: 0.075 part, nano-silica: 0.35 part, coconut oil diethanolamide: 1.5 parts, polyvinyl alcohol: 3 parts, water: 135 parts.

[0048] The preparation method is as follows:

[0049] Step 1: Weigh sodium dodecyl sulfate, dodecyldimethylamine oxide, α-olefin sulfonate, N,N-dimethylacetamide, hydroxypropyl methylcellulose, nano-silica, coconut oil diethanolamide, polyvinyl alcohol and water according to the ratio.

[0050] Step 2: Put water and N,N-dimethylacetamide into a container and stir evenly at medium speed; after mixing evenly, start rapid stirring, and slowly add all the nano-silica during the stirring process.

[0051] Step 3: Keep rapid stirring and add coconut oil diethanolamide and polyvinyl alcohol in sequence.

[0052] Step 4: Change the stirring speed to medium speed, add dodecyldimethylamine oxide and keep stirring at medium speed for 1 - 2 min.

[0053] Step 5: Keep slow stirring and slowly add α-olefin sulfonate and sodium dodecyl sulfate in sequence.

[0054] Step 6: Raise the temperature to 60 °C, keep stirring, and disperse and add hydroxypropyl methylcellulose; after adding, continue to keep slow stirring for 10 min.

[0055] Step 7: Naturally cool to room temperature.

[0056] In this embodiment, the slow stirring speed is 60 r / min; the medium stirring speed ranges from 200 r / min; the fast stirring speed ranges from 500 r / min.

[0057] Example 2

[0058] 2.1 parts of sodium dodecyl sulfate, 0.7 part of dodecyldimethylamine oxide, 1.2 parts of α-olefin sulfonate, 1 part of N,N-dimethylacetamide, 0.05 part of hydroxypropyl methylcellulose, 0.2 part of nano-silica, 1 part of coconut oil diethanolamide, 2 parts of polyvinyl alcohol, 150 parts of water.

[0059] The preparation method is the same as that of Example 1.

[0060] Example 3

[0061] 2.7 parts of sodium dodecyl sulfate, 0.9 part of dodecyldimethylamine oxide, 2.4 parts of α-olefin sulfonate, 2.5 parts of N,N-dimethylacetamide, 0.1 part of hydroxypropyl methylcellulose, 0.5 part of nano-silica, 2 parts of coconut oil diethanolamide, 4 parts of polyvinyl alcohol, 120 parts of water.

[0062] The preparation method is the same as that of Example 1.

[0063] Comparative Example 1

[0064] 2.4 parts of sodium dodecyl sulfate, 1.8 parts of α-olefin sulfonate, 1.75 parts of N,N-dimethylacetamide, 0.075 part of hydroxypropyl methylcellulose, 0.35 part of nano-silica, 1.5 parts of coconut oil diethanolamide, 3 parts of polyvinyl alcohol, 135 parts of water.

[0065] The preparation method is the same as that of Example 1, except that dodecyldimethylamine oxide is not added.

[0066] Comparative Example 2

[0067] 2.4 parts of sodium dodecyl sulfate, 0.8 part of dodecyldimethylamine oxide, 1.75 parts of N,N-dimethylacetamide, 0.075 part of hydroxypropyl methylcellulose, 0.35 part of nano-silica, 1.5 parts of coconut oil diethanolamide, 3 parts of polyvinyl alcohol, 135 parts of water.

[0068] The preparation method is the same as that of Example 1, except that α-olefin sulfonate is not added.

[0069] Comparative Example 3

[0070] 2.4 parts of sodium dodecyl sulfate, 0.8 part of dodecyldimethylamine oxide, 1.8 parts of α-olefin sulfonate, 0.075 part of hydroxypropyl methylcellulose, 0.35 part of nano-silica, 1.5 parts of coconut oil diethanolamide, 3 parts of polyvinyl alcohol, 135 parts of water.

[0071] The preparation method is the same as that of Example 1, with the only difference being that N,N-dimethylacetamide is not added.

[0072] Comparative Example 4

[0073] 2.4 parts of sodium dodecyl sulfate, 0.8 part of dodecyldimethylamine oxide, 1.8 parts of α-olefin sulfonate, 1.75 parts of N,N-dimethylacetamide, 0.35 part of nano-silica, 1.5 parts of coconut oil diethanolamide, 3 parts of polyvinyl alcohol, 135 parts of water.

[0074] The preparation method is the same as that of Example 1, with the only difference being that hydroxypropyl methylcellulose is not added.

[0075] Comparative Example 5

[0076] 2.4 parts of sodium dodecyl sulfate, 0.8 part of dodecyldimethylamine oxide, 1.8 parts of α-olefin sulfonate, 1.75 parts of N,N-dimethylacetamide, 0.075 part of hydroxypropyl methylcellulose, 1.5 parts of coconut oil diethanolamide, 3 parts of polyvinyl alcohol, 135 parts of water.

[0077] The preparation method is the same as that of Example 1, with the only difference being that nano-silica is not added.

[0078] Comparative Example 6

[0079] 2.4 parts of sodium dodecyl sulfate, 0.8 part of dodecyldimethylamine oxide, 1.8 parts of α-olefin sulfonate, 1.75 parts of N,N-dimethylacetamide, 0.075 part of hydroxypropyl methylcellulose, 0.35 part of nano-silica, 3 parts of polyvinyl alcohol, 135 parts of water.

[0080] The preparation method is the same as that of Example 1, with the only difference being that coconut oil diethanolamide is not added.

[0081] Comparative Example 7

[0082] 2.4 parts of sodium dodecyl sulfate, 0.8 part of dodecyldimethylamine oxide, 1.8 parts of α-olefin sulfonate, 1.75 parts of N,N-dimethylacetamide, 0.075 part of hydroxypropyl methylcellulose, 0.35 part of nano-silica, 1.5 parts of coconut oil diethanolamide, 135 parts of water.

[0083] The preparation method is the same as that of Example 1, with the only difference being that polyvinyl alcohol is not added.

[0084] Comparative Example 8

[0085] 2.4 parts of sodium dodecyl sulfate, 0.8 part of dodecyldimethylamine oxide, 1.8 parts of α-olefin sulfonate, 1.75 parts of N,N-dimethylacetamide, 0.075 part of hydroxypropyl methylcellulose, 0.1 part of nano-silica, 1.5 parts of coconut oil diethanolamide, 3 parts of polyvinyl alcohol, 135 parts of water.

[0086] The preparation method is the same as that of Example 1.

[0087] Comparative Example 9

[0088] 2.4 parts of sodium dodecyl sulfate, 0.8 part of dodecyldimethylamine oxide, 1.8 parts of α-olefin sulfonate, 1.75 parts of N,N-dimethylacetamide, 0.075 part of hydroxypropyl methylcellulose, 0.35 part of nano-silica, 1.5 parts of coconut oil diethanolamide, 8 parts of polyvinyl alcohol, 135 parts of water.

[0089] The preparation method is the same as that of Example 1.

[0090] Comparative Example 10

[0091] 4.8 parts of sodium dodecyl sulfate, 1.6 parts of dodecyldimethylamine oxide, 3.6 parts of α-olefin sulfonate, 1.75 parts of N,N-dimethylacetamide, 0.075 part of hydroxypropyl methylcellulose, 0.35 part of nano-silica, 1.5 parts of coconut oil diethanolamide, 3 parts of polyvinyl alcohol, 135 parts of water.

[0092] The preparation method is the same as that of Example 1.

[0093] Comparative Example 11

[0094] 2.4 parts of sodium dodecylbenzenesulfonate, 0.8 part of dodecyldimethylamine oxide, 1.8 parts of α-olefin sulfonate, 1.75 parts of N,N-dimethylacetamide, 0.075 part of hydroxypropyl methylcellulose, 0.35 part of nano-silica, 1.5 parts of coconut oil diethanolamide, 3 parts of polyvinyl alcohol, 135 parts of water.

[0095] The preparation method is the same as that of Example 1.

[0096] Comparative Example 12

[0097] 2.4 parts of sodium dodecyl sulfate, 0.8 part of dodecyldimethylamine oxide, 1.8 parts of α-olefin sulfonate, 1.75 parts of N,N-dimethylacetamide, 0.075 part of hydroxypropyl methylcellulose, 0.35 part of nano-silica, 1.5 parts of coconut oil diethanolamide, 3 parts of polyvinyl alcohol, 135 parts of water.

[0098] The preparation method is the same as that of Example 1, except that the nano-silica in the raw materials is hydrophilic.

[0099] Comparative Example 13

[0100] 2.4 parts of sodium dodecyl sulfate, 0.8 part of dodecyldimethylamine oxide, 1.8 parts of α-olefin sulfonate, 1.75 parts of N,N-dimethylacetamide, 0.075 part of hydroxypropyl methylcellulose, 0.35 part of nano-silica, 1.5 parts of coconut oil diethanolamide, 3 parts of polyvinyl alcohol, and 135 parts of water.

[0101] The preparation method was the same as that of Example 1, except that the particle size of the nano-silica in the raw materials was 100 nm.

[0102] The test experiments of the examples and comparative examples included the foaming ratio test and the half-life test; the foam images were collected by an electron magnifying glass, and the parametric analysis of the foam size was carried out using ImageJ software; the slump test was used to evaluate the plastic flowability of the improved clay, and the water contents of the soil body were 25% and 35% respectively.

[0103] The test results are as follows:

[0104] The results of the foaming ratio, half-life test and foam size parameter analysis are shown in Table 1.

[0105] Table 1 Results of foaming ratio, half-life test and foam size parameter analysis

[0106]

[0107] The slump test results under different water contents of the soil body are shown in Table 2.

[0108] Table 2 Slump test results under different water contents of the soil body

[0109]

[0110]

[0111] According to the test results, it can be seen that the foaming agents prepared in Examples 1-3 have uniform and delicate foaming, smaller overall size, longer half-life and better stability; the slump test shows that it can still improve the muck to a better plastic flow state under lower water content conditions.

[0112] For Comparative Example 5, compared with the results of the examples and other comparative examples, the foaming volume is large and the uniformity is poor. The slump test results show that the improved soil has poor plastic flowability, and the difference in the use effect is particularly obvious under lower water content conditions.

[0113] For Comparative Example 8, the foaming ratio is large, the foam volume is large, the stability becomes poor, and the application effect is not good.

[0114] Comparative Example 9 has extremely poor foam stability, and polyvinyl alcohol shows foam suppression at this concentration.

[0115] Comparative Example 10 is generally similar to Example 1, but its stability is slightly worse and its economy is worse.

[0116] In Comparative Example 11, the comprehensive effects are all inferior to those of Example 1.

[0117] In Comparative Example 12, after the nano-silica is hydrophilically treated, the foam stabilizing effect is extremely insignificant.

[0118] In Comparative Example 13, when large-particle nano materials are used, the comprehensive indicators all become worse.

[0119] It should be noted that the above examples are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the given examples, those of ordinary skill in the art can modify or equivalently replace the technical solutions of the present invention according to needs, without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A nano-based shield muck improvement foam agent, characterized in that, By weight parts, it consists of the following components: 2.1 - 2.7 parts of sodium dodecyl sulfate, 0.7 - 0.9 parts of dodecyldimethylamine oxide, 1.2 - 2.4 parts of α-olefin sulfonate, 1 - 2.5 parts of N,N-dimethylacetamide, 0.05 - 0.1 parts of hydroxypropyl methylcellulose, 0.2 - 0.5 parts of nano-silica, 1 - 2 parts of coconut oil diethanolamide, 2 - 4 parts of polyvinyl alcohol, and 120 - 150 parts of water.

2. The nano-based shield muck improvement foaming agent according to claim 1, characterized in that, The sodium dodecyl sulfate, α-olefin sulfonate, and dodecyldimethylamine oxide are all of analytical purity.

3. The nano-based shield muck improvement foaming agent according to claim 1, characterized in that, The selected nano-silica has a particle size of 30 - 50 nm.

4. The nano-based shield muck improvement foam agent according to claim 1, wherein The nano-silica is hydrophobic nano-silica.

5. The preparation method of the nano-based shield muck improvement foam agent according to any one of claims 1-4, characterized in that, The preparation method includes: S1. After mixing water and N,N-dimethylacetamide evenly, then successively add nano-silica, coconut oil diethanolamide, polyvinyl alcohol, dodecyldimethylamine oxide, α-olefin sulfonate, and sodium dodecyl sulfate thereto; S2: Heat to 50 - 60 °C, add hydroxypropyl methylcellulose to the mixed solution in step S1, and naturally cool to room temperature.

6. The preparation method according to claim 5, characterized in that, In steps S1 and S2, stirring treatment is performed when adding the component raw materials.

7. The preparation method according to claim 5, characterized in that, In step S1, water and N,N-dimethylacetamide are stirred and mixed evenly at a medium speed; When adding the nano-silica, coconut oil diethanolamide, and polyvinyl alcohol, they are all stirred and mixed evenly at a high speed; When adding the dodecyldimethylamine oxide, it is stirred and mixed evenly at a medium speed, and after the addition, keep stirring at a medium speed for 1 - 2 min; When adding the α-olefin sulfonate and sodium dodecyl sulfate, they are stirred and mixed evenly at a low speed.

8. The preparation method according to claim 5, characterized in that, In step S2, when adding the hydroxypropyl methylcellulose, it is stirred and mixed evenly at a low speed, and after the addition, continue to keep stirring at a low speed for 5 - 10 min.

9. For the preparation method according to claim 7 or 8, in its special operation, the low-speed stirring speed range is 50 - 100 r / min; the medium-speed stirring speed range is 150 - 300 r / min; the high-speed stirring speed range is 450 - 600 r / min.

10. The application of the nano-based shield muck improvement foam agent according to any one of claims 1 - 4 in muck improvement; Furthermore, the application environment is specifically the shield construction environment.

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