A synchronous grouting material for shield muck and a preparation method thereof

Abstract

The application provides a shield muck synchronous grouting material and a preparation method thereof. The grouting material comprises the following raw materials in parts by weight: 30-40 parts of cementing material, 50-65 parts of shield muck, 4-6 parts of polymer emulsion, 2-4 parts of activator, 0.1-0.3 parts of early strength agent, 1-2 parts of anti-mud polycarboxylic acid water reducer, 3-5 parts of quaternary ammonium salt coupling agent modified nano magnesium oxide, and 18-32 parts of water. The anti-mud polycarboxylic acid water reducer is prepared by copolymerization of a mono-alkenyl polyether macromonomer, an acrylate derivative and sucrose monoallyl ether at a molar ratio of 1:0.1-0.3:0.15-0.35. Under the synergistic effect of the quaternary ammonium salt coupling agent modified nano magnesium oxide and the anti-mud polycarboxylic acid water reducer, the grouting material has excellent anti-permeability.

Description

A material for synchronous grouting of tunnel boring machine excavation and its preparation method Technical Field

[0001] This invention belongs to the field of grouting material technology, specifically relating to a synchronous grouting material for shield tunneling excavation and its preparation method. Background Technology

[0002] During tunnel construction, on the one hand, it is necessary to improve construction technology to cope with numerous technical challenges, including traversing soft, water-rich strata, weathered rock layers, soft clay layers, sand layers, corrosive water environments, and various underground pipelines; on the other hand, it is also necessary to prevent tunnel seepage and ground subsidence in subway tunnels. Simultaneous grouting technology involves injecting grouting materials with appropriate early and final strength into the tunnel during shield excavation to fill the gaps at the shield tail. This can inhibit natural soil deformation, control ground settlement, and ensure environmental safety. It serves as the first line of defense for tunnel lining waterproofing, possessing a certain degree of waterproofing function, and also acts as a reinforcing layer for the lining structure, improving its durability.

[0003] With the rapid development of shield tunnel engineering in my country, the amount of excavated soil from shield tunnels is increasing dramatically. Due to the limited construction sites, the excavated soil often needs to be disposed of off-site. However, the transportation and disposal costs of large amounts of excavated soil are high, and the transportation and disposal process can easily have adverse effects on the surrounding ecological environment. During the excavation process, tunnel boring machines (TBMs) encounter various types of rock and soil, which generate various types of TBM slag, including sandy slag, clayey slag, mixed slag, and organic slag. Among them, using sandy slag as the sand source for synchronous grouting material has the advantages of being harmless and enabling effective resource utilization, and can also achieve cost reduction and efficiency improvement. It has now received widespread attention and become a research hotspot. For example, patent CN111072347B discloses a method for preparing wall grouting material using waste diorite slag in earth pressure TBMs, which includes the following steps: (1) cleaning and drying the slag discharged during the excavation of the diorite stratum; (2) sending the slag treated in step (1) to a screening machine for screening to remove large particles; (3) replacing part of the medium sand in the original wall grouting material with the slag after screening, and then adding bentonite, fly ash, cement and water to make wall grouting material. Patent CN101928122B discloses a synchronous grouting material for tunnels and its preparation method. This grouting material uses a slag slurry with a clay and fine sand content of 30%-65% and a soil-to-sand weight ratio of 0.1-0.18:1 as the main raw material. The slurry is prepared by adding 80-120 kg of cement, 300-450 kg of fly ash, 200-500 kg of water or slurry, and 3-10 kg of sodium carboxymethyl cellulose per cubic meter of slag slurry. The slurry density is 1.85-2.05 g / cm³. 3 The consistency of the slurry is between 10.5 and 12 cm.

[0004] The above describes technologies that partially or completely replace fine aggregates with sandy slag, which can significantly reduce material costs, realize waste resource utilization, and alleviate the shortage of natural sand resources. However, to reduce processing costs and shorten construction cycles, the mud content of sandy slag is usually not reduced to a particularly low level (the mud content of Class III sand in GB / T 14684-2011 is ≤5%), resulting in a loose internal structure, increased porosity, and decreased impermeability of the grouting material's aggregate. Therefore, it is necessary to improve grouting materials that partially or completely replace fine aggregates with sandy slag to enhance their impermeability. Summary of the Invention

[0005] To overcome the problem of loose internal structure, increased porosity, and decreased impermeability of grouting materials caused by the high mud content of shield tunneling excavation soil, this invention provides a synchronous grouting material for shield tunneling excavation soil and its preparation method. The raw material of the grouting material includes a quaternary ammonium salt coupling agent-modified nano-magnesium oxide with a surface grafted with cationic quaternary ammonium salts. Because mud particles preferentially adsorb cations, the quaternary ammonium salt coupling agent-modified nano-magnesium oxide will adsorb onto the surface of the mud particles. On the one hand, it acts as a sacrificial agent, reducing the adsorption of polycarboxylate superplasticizer by the mud particles; on the other hand, as... During the hydration reaction of the cementitious material, magnesium oxide also hydrates and expands in volume. The expansion force compresses the surrounding water-absorbing and expanding mud particles, making the mud particles more compact and reducing the risk of loose internal structure of the stone. In addition, the grouting material also includes a mud-resistant polycarboxylate superplasticizer copolymerized with monoalkenyl polyether macromonomers, acrylate derivatives, and sucrose monoallyl ether as polymer monomers. This superplasticizer can make the hydration reaction of the cementitious material more complete and has a synergistic effect with the quaternary ammonium salt coupling agent to modify nano-magnesium oxide and further improve the impermeability of the grouting material.

[0006] To achieve the above objectives, the following specific technical solutions are adopted:

[0007] A material for synchronous grouting of tunnel boring machine (TBM) slag includes the following raw materials in parts by weight: 30-40 parts cementitious material, 50-65 parts TBM slag, 4-6 parts polymer emulsion, 2-4 parts activator, 0.1-0.3 parts early strength agent, 1-2 parts anti-mud polycarboxylate superplasticizer, and 3-5 parts quaternary ammonium salt coupling agent modified nano-magnesium oxide; wherein the anti-mud polycarboxylate superplasticizer is copolymerized from monoalkenyl polyether macromonomer, acrylate derivative, and sucrose monoallyl ether in a molar ratio of 1:0.1-0.3:0.15-0.35.

[0008] Sucrose monoallyl ether can increase the steric hindrance of polycarboxylate superplasticizer, prevent the adsorption of superplasticizer by clay particles in shield tunnel slag, weaken the interaction between superplasticizer and clay particles, and improve the dispersibility and slump retention effect of superplasticizer.

[0009] The monoalkenyl polyether macromonomers have a number-average molecular weight of 2000-4000 and are selected from one or a combination of two or more of allyl polyoxyethylene ether, methyl allyl polyoxyethylene ether, and isopentenyl polyoxyethylene ether.

[0010] The acrylate derivative is selected from one or a combination of two or more of methyl methacrylate, methyl acrylate, ethyl acrylate, and ethyl methacrylate.

[0011] The anti-mud polycarboxylate superplasticizer is prepared by a method comprising the following steps:

[0012] 1) Add the monoalkenyl polyether macromonomer and sucrose monoallyl ether to water and stir until completely dissolved to obtain a solution;

[0013] 2) Under an inert atmosphere, the solution obtained in step 1) is heated, and an initiator solution and an acrylate derivative solution are added dropwise. After the addition is complete, the reaction is carried out at a constant temperature. After the reaction is completed, the solution is cooled to room temperature, and the solid content is adjusted to obtain the anti-mud polycarboxylate superplasticizer.

[0014] The amount of water used in step 1) is 5-8 times the combined mass of the monoalkenyl polyether macromonomer and the sucrose monoallyl ether.

[0015] Step 2) involves heating to 60-80℃. The dropping time is 0.5-1 h. The isothermal reaction time is 1-3 h. The initiator is selected from one or a combination of two or more of sodium persulfate, potassium persulfate, and ammonium persulfate. The amount of initiator used is 0.1-0.3 wt% of the sum of the masses of the monoalkenyl polyether macromonomer, acrylate derivative, and sucrose monoallyl ether. The solid content is adjusted to 35-40 wt% by adding water or distillation. The solvent for the initiator solution is water with a concentration of 10-15 wt%. The solvent for the acrylate derivative solution is water with a concentration of 0.1-0.2 mol / L.

[0016] The quaternary ammonium salt coupling agent is selected from one or a combination of two or more of trimethyl[3-(trimethoxysilyl)propyl]ammonium chloride, N,N,N-tri-n-butyl-N-trimethoxysilylpropylammonium chloride, and trimethyl[3-(triethoxysilyl)propyl]ammonium chloride.

[0017] The average particle size of the nano-magnesium oxide is 50-100 nm. The amount of the quaternary ammonium salt coupling agent is 3-5 wt% of the nano-magnesium oxide.

[0018] The quaternary ammonium salt coupling agent modified nano-magnesium oxide is prepared by a method comprising the following steps:

[0019] Nano-magnesium oxide was dispersed in an alcohol solution, a quaternary ammonium salt coupling agent was added, and the mixture was stirred to carry out the reaction. After the reaction was completed, the nano-magnesium oxide was filtered, washed, and dried to obtain quaternary ammonium salt silane coupling agent modified nano-magnesium oxide.

[0020] The alcohol solution is a mixture of alcohol and water at a mass ratio of 1-4:1. The mass ratio of nano-magnesium oxide to the alcohol solution is 1:18-20. The stirring temperature is 20-40℃. The reaction time is 12-24 hours. The washing is performed 1-3 times with water. The alcohol is selected from one or a combination of two or more of methanol, ethanol, and isopropanol.

[0021] The fineness modulus of the shield tunneling slag is 1-2, the mud content is 15-20%, the moisture content is 5-15%, and the pH is 7-8.

[0022] The cementitious material is a mixture of red mud, high-sulfur tailings powder, slag, and steel slag in a mass ratio of 1-2:2-4:1-2:1-2.

[0023] The polymer emulsion has a solid content of 40-55% and is selected from one or a combination of two or more of styrene-acrylic emulsion, styrene-butadiene emulsion, polyvinyl acetate-ethylene copolymer emulsion, and waterborne epoxy resin emulsion.

[0024] The early strength agent is selected from one or a combination of two or more of sodium silicate, sodium nitrate, sodium acetate, triethanolamine, triisopropanolamine, and methanol.

[0025] The activator is selected from one or a combination of two or more of calcium hydroxide, sodium carbonate, calcium oxide or calcium sulfate.

[0026] The red mud is Bayer process red mud, with an average particle size of 10-30 μm and a specific surface area of ​​800-1200 m². 2 / kg.

[0027] The high-sulfur tailings powder has a residue of less than 20% on a 45μm square-hole sieve and a specific surface area of ​​400-500m². 2 / kg, SO3 content 10-15%, Fe2O3 content 15-20%, SiO2 content 35-45%.

[0028] The slag is selected from one or a combination of two of S95 grade slag powder and S105 grade slag powder.

[0029] The steel slag powder is selected from one or a combination of two of G85 grade steel slag powder and G95 grade steel slag powder.

[0030] The present invention also provides a method for preparing the above-mentioned shield tunneling slag synchronous grouting material, comprising the following steps:

[0031] Mixture A is prepared by uniformly mixing cementitious materials, shield tunneling slag, quaternary ammonium salt coupling agent modified nano magnesium oxide, activator, and early strength agent. Simultaneously, mixture B is prepared by uniformly mixing polymer emulsion, anti-mud polycarboxylate superplasticizer, and water. Then, mixture B is added to mixture A and stirred to form a slurry, thus obtaining the shield tunneling slag synchronous grouting material.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] The grouting material of this invention contains a quaternary ammonium salt coupling agent-modified nano-magnesium oxide with a surface grafted with cationic quaternary ammonium salt. Because clay particles preferentially adsorb cations, the quaternary ammonium salt coupling agent-modified nano-magnesium oxide adsorbs onto the surface of the clay particles. On one hand, it acts as a sacrificial agent, reducing the adsorption of polycarboxylate superplasticizer by the clay particles. On the other hand, as the cementitious material undergoes hydration, the magnesium oxide also hydrates and expands in volume. This expansion force compresses the surrounding water-absorbing and expanding clay particles, making them more compact and reducing the risk of a loose internal structure in the grouting mass. Furthermore, the grouting material also includes an anti-mud polycarboxylate superplasticizer copolymerized from monoalkenyl polyether macromonomers, acrylate derivatives, and sucrose monoallyl ether. This superplasticizer allows for a more complete hydration reaction of the cementitious material and synergistically enhances the impermeability of the grouting material with the quaternary ammonium salt coupling agent-modified nano-magnesium oxide. Detailed Implementation

[0034] The present invention will be further described below with reference to specific embodiments, but is not limited to the contents of the specification. Unless otherwise specified, all "parts" mentioned in the embodiments of the present invention are parts by weight. All reagents used are commercially available in the art.

[0035] The nano-magnesium oxide has an average particle size of 50 nm and was purchased from Qinghe County Chaotai Metal Materials Co., Ltd.

[0036] Dow PRIMAL DC-420 styrene-acrylic emulsion, with a solid content of 48%, was purchased from Qingdao Pintel Trading Co., Ltd.

[0037] Allyl polyoxyethylene ether APEG-2400 has a number-average molecular weight of 2400 and was purchased from Jiangsu Haian Petrochemical Co., Ltd.

[0038] The number-average molecular weight of isopentenyl polyoxyethylene ether TPEG-4000 is 4000, and it was purchased from Liaoning Aoke Chemical Co., Ltd.

[0039] The shield tunneling slag has a fineness modulus of 1.6, a mud content of 17.5%, a moisture content of 10.5%, and a pH of 7.6. It comes from the shield tunneling sand of Beijing Metro Line 3.

[0040] The Bayer process red mud was purchased from Shandong Aluminum Industry Co., Ltd., with an average particle size of 17.3 μm and a specific surface area of ​​1180 m².2 / kg.

[0041] The high-sulfur tailings powder was purchased from Zibo Qirong Building Materials Co., Ltd. It had a 14.5% residue on a 45μm square-hole sieve and a specific surface area of ​​450 m². 2 / kg, SO3 content 13.5%, Fe2O3 content 16.0%, SiO2 content 40%.

[0042] Example 1

[0043] 1) Add 1 mol TPEG-4000 and 0.35 mol sucrose monoallyl ether to 5 times the mass of the two monomers and water, and stir until completely dissolved to obtain a solution;

[0044] 2) Under a nitrogen atmosphere, the solution obtained in step 1) was heated to 80°C, and simultaneously a 10wt% ammonium persulfate aqueous solution (added dropwise over 40 min, the mass of ammonium persulfate being 0.3wt% of the sum of the masses of TPEG-4000, sucrose monoallyl ether, and methyl acrylate) and 1.5L of a 0.2mol / L methyl acrylate aqueous solution (added dropwise over 60 min) were added dropwise. The reaction was carried out at a constant temperature for 3 h. After the reaction was completed, the solution was cooled to room temperature, and the water was removed by distillation to adjust the solid content to 45wt%, yielding an anti-mud polycarboxylate superplasticizer. The weight-average molecular weight was 58,000 as determined by GPC.

[0045] 3) Disperse 1 kg of nano magnesium oxide in 20 kg of an alcohol solution made of ethanol and water in a mass ratio of 4:1, add 50 g of trimethyl[3-(triethoxysilyl)propyl]ammonium chloride, stir at 25 °C for 24 h, filter, wash with water 3 times, and dry at 80 °C to constant weight to obtain quaternary ammonium salt silane coupling agent modified nano magnesium oxide.

[0046] 4) Mix 4 kg of cementitious material composed of red mud, high-sulfur tailings powder, S95 grade slag powder, and G85 grade steel slag powder in a mass ratio of 2:4:1:1, 6.5 kg of shield tunneling slag, 0.5 kg of quaternary ammonium salt coupling agent modified nano-magnesium oxide, 0.4 kg of calcium hydroxide, and 0.03 kg of triethanolamine evenly to obtain mixture A. At the same time, mix 0.6 kg of PRIMAL DC-420 styrene-acrylic emulsion, 0.2 kg of anti-mud polycarboxylate superplasticizer, and 3.2 kg of water evenly to obtain mixture B. Then add mixture B to mixture A and stir to make slurry, which is the shield tunneling slag synchronous grouting material.

[0047] Example 2

[0048] The rest is the same as in Example 1, except that in step 1), the amount of sucrose monoallyl ether used is 0.15 mol. The resulting anti-mud polycarboxylate superplasticizer has a weight-average molecular weight of 54,000 as determined by the GPC method.

[0049] Example 3

[0050] The rest is the same as in Example 1, except that in step 1), TPEG-4000 is replaced with an equimolar amount of APEG-2400. The weight-average molecular weight of the anti-mud polycarboxylate superplasticizer, measured by GPC method, is 56,000.

[0051] Example 4

[0052] The rest is the same as in Example 1, except that in step 3), the amount of trimethyl[3-(triethoxysilyl)propyl]ammonium chloride used is 30g.

[0053] Example 5

[0054] The rest is the same as in Example 1, except that in step 4), the amount of quaternary ammonium salt coupling agent modified nano magnesium oxide is 0.3 kg.

[0055] Example 6

[0056] The rest is the same as in Example 1, except that in step 4), the amount of anti-mud polycarboxylate superplasticizer used is 0.1 kg.

[0057] Example 7

[0058] 1) Add 1 mol APEG-2400 and 0.35 mol sucrose monoallyl ether to 5 times the mass of the two monomers and water, and stir until completely dissolved to obtain a solution;

[0059] 2) Under a nitrogen atmosphere, the solution obtained in step 1) was heated to 80°C, and simultaneously a 10wt% ammonium persulfate aqueous solution (added dropwise over 40 min, the mass of ammonium persulfate being 0.3wt% of the sum of the masses of TPEG-4000, sucrose monoallyl ether, and methyl acrylate) and 1.5L of a 0.2mol / L methyl acrylate aqueous solution (added dropwise over 60 min) were added dropwise. The reaction was carried out at a constant temperature for 3 h. After the reaction was completed, the solution was cooled to room temperature, and the water was distilled off to adjust the solid content to 45wt%, yielding an anti-mud polycarboxylate superplasticizer. The weight-average molecular weight was 56,000 as determined by GPC.

[0060] 3) Disperse 1 kg of nano magnesium oxide in 20 kg of an alcohol solution made of ethanol and water in a mass ratio of 4:1, add 50 g of trimethyl[3-(trimethoxysilyl)propyl]ammonium chloride, stir at 25 °C for 24 h, filter, wash with water 3 times, and dry at 80 °C to constant weight to obtain quaternary ammonium salt silane coupling agent modified nano magnesium oxide.

[0061] 4) Mix 3 kg of cementitious material composed of red mud, high-sulfur tailings powder, S95 grade slag powder, and G85 grade steel slag powder in a mass ratio of 1:2:2:2, 5 kg of shield tunnel slag, 0.3 kg of quaternary ammonium salt coupling agent modified nano-magnesium oxide, 0.2 kg of calcium hydroxide, and 0.03 kg of triethanolamine evenly to obtain mixture A. At the same time, mix 0.6 kg of PRIMAL DC-420 styrene-acrylic emulsion, 0.2 kg of anti-mud polycarboxylate superplasticizer, and 2.4 kg of water evenly to obtain mixture B. Then add mixture B to mixture A and stir to make slurry, which is the shield tunnel slag synchronous grouting material.

[0062] Comparative Example 1

[0063] The rest is the same as in Example 1, except that in step 3), 3-aminopropyltrimethoxysilane is used instead of trimethyl[3-(triethoxysilyl)propyl]ammonium chloride.

[0064] Comparative Example 2

[0065] The rest is the same as in Example 1, except that sucrose monoallyl ether is not added in step 1), and the amount of 0.2 mol / L methyl acrylate aqueous solution used in step 2) is 3.25 L (dropped over 120 min). The weight-average molecular weight determined by GPC is 53,000.

[0066] Comparative Example 3

[0067] The rest is the same as in Example 1, except that in step 4), an equal mass of conventional polycarboxylate superplasticizer - BASF polycarboxylate superplasticizer RHEOPLUS 413 - is used instead of the anti-mud polycarboxylate superplasticizer.

[0068] The grouting materials prepared in the above embodiments and comparative examples were subjected to the following performance tests:

[0069] Cement mortar fluidity: The fluidity of cement mortar was tested in accordance with the standard GB / T 2419-2005. The mortar composition was determined according to the specific implementation examples and comparative examples.

[0070] Impermeability: The test was conducted in accordance with the standard JGJ / T 70-2009 Test Method for Basic Performance of Building Mortar. The formula for calculating the impermeability grade of the sample is as follows: P = 10H-1, where P represents the impermeability grade of the sample and H represents the water pressure (MPa) when 3 out of 6 samples show water seepage.

[0071] Compressive strength: Tested according to standard GB / T 177-85 Cement Mortar Strength Test Method, with mold specifications of 40mm×40mm×160mm; Curing conditions for specimens: air curing, room temperature 20℃, relative humidity 85%.

[0072] Table 1 Performance Test Results

[0073]

[0074]

[0075] As can be seen from Table 1, under the synergistic effect of anti-mud polycarboxylate superplasticizer and quaternary ammonium salt coupling agent modified nano-magnesium oxide, the grouting material prepared by this invention has excellent dispersion performance and dispersion retention performance, indicating that the cementitious material particles can maintain a good dispersion state, the mud particles do not have an adverse effect on the normal hydration of the cementitious material particles, the internal structure of the stone body is dense, and the impermeability is excellent.

[0076] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. A material for synchronous grouting of tunnel boring machine excavation waste, characterized in that, The raw materials include the following parts by weight: 30-40 parts cementitious material, 50-65 parts shield tunnel slag, 4-6 parts polymer emulsion, 2-4 parts activator, 0.1-0.3 parts early strength agent, 1-2 parts anti-mud polycarboxylate superplasticizer, 3-5 parts quaternary ammonium salt coupling agent modified nano magnesium oxide, and 18-32 parts water; the anti-mud polycarboxylate superplasticizer is copolymerized from monoalkenyl polyether macromonomer, acrylate derivative, and sucrose monoallyl ether in a molar ratio of 1:0.1-0.3:0.15-0.

35.

2. The shield tunneling spoil synchronous grouting material according to claim 1, characterized in that, The monoalkenyl polyether macromonomer has a number average molecular weight of 2000-4000 and is selected from one or a combination of two or more of allyl polyoxyethylene ether, methyl allyl polyoxyethylene ether, and isopentenyl polyoxyethylene ether; the acrylate derivative is selected from one or a combination of two or more of methyl methacrylate, methyl acrylate, ethyl acrylate, and ethyl methacrylate.

3. The shield tunneling spoil synchronous grouting material according to claim 1, characterized in that, The anti-mud polycarboxylate superplasticizer is prepared by the following steps: 1) adding monoalkenyl polyether macromonomer and sucrose monoallyl ether to water and stirring until completely dissolved to obtain a solution; 2) heating the solution obtained in step 1) under an inert atmosphere, while adding an initiator solution and an acrylate derivative solution dropwise, and reacting at a constant temperature after the addition is complete. After the reaction is completed, cooling to room temperature and adjusting the solid content, the anti-mud polycarboxylate superplasticizer is obtained.

4. The shield tunneling spoil synchronous grouting material according to claim 3, characterized in that, Step 1) The amount of water used is 5-8 times the combined mass of the monoalkenyl polyether macromonomer and the sucrose monoallyl ether.

5. The shield tunneling spoil synchronous grouting material according to claim 3, characterized in that, Step 2) The initiator is selected from one or a combination of two or more of sodium persulfate, potassium persulfate, and ammonium persulfate; the amount of the initiator is 0.1-0.3 wt% of the sum of the mass of the monoalkenyl polyether macromonomer, acrylate derivative, and sucrose monoallyl ether.

6. The shield tunneling spoil synchronous grouting material according to claim 1, characterized in that, The quaternary ammonium salt coupling agent modified nano-magnesium oxide is prepared by a method including the following steps: dispersing nano-magnesium oxide in an alcohol solution, adding quaternary ammonium salt coupling agent, stirring to carry out the reaction, and after the reaction is completed, filtering, washing, and drying to obtain quaternary ammonium salt coupling agent modified nano-magnesium oxide.

7. The shield tunneling spoil synchronous grouting material according to claim 6, characterized in that, The quaternary ammonium salt coupling agent is selected from one or a combination of two or more of trimethyl[3-(trimethoxysilyl)propyl]ammonium chloride, N,N,N-tri-n-butyl-N-trimethoxysilanepropylammonium chloride, and trimethyl[3-(triethoxysilyl)propyl]ammonium chloride; the average particle size of the nano-magnesium oxide is 50-100 nm; and the amount of the quaternary ammonium salt coupling agent is 3-5 wt% of the nano-magnesium oxide.

8. The shield tunneling spoil synchronous grouting material according to claim 6, characterized in that, The alcohol solution is a mixture of alcohol and water in a mass ratio of 1-4:1; the mass ratio of nano-magnesium oxide to the alcohol solution is 1:18-20.

9. The shield tunneling spoil synchronous grouting material according to claim 1, characterized in that, The fineness modulus of the shield tunneling excavated soil is 1-2, the mud content is 15-20%, the water content is 5-15%, and the pH is 7-8.

10. The method for preparing the shield tunneling spoil synchronous grouting material according to any one of claims 1-9, characterized in that, The process includes the following steps: mixing cementitious materials, shield tunnel slag, quaternary ammonium salt coupling agent modified nano magnesium oxide, activator, and early strength agent evenly to obtain mixture A; simultaneously mixing polymer emulsion, anti-mud polycarboxylate superplasticizer, and water evenly to obtain mixture B; then adding mixture B to mixture A and stirring to form a slurry, thus obtaining the shield tunnel slag synchronous grouting material.

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