Dynamic hydraulic pressure resistant cement-based plugging material for tunnel maintenance and preparation method of dynamic hydraulic pressure resistant cement-based plugging material

Abstract

The invention discloses an anti-hydrodynamic-pressure cement-based plugging material for tunnel maintenance and a preparation method thereof. The anti-hydrodynamic-pressure cement-based plugging material comprises the following raw materials in percentage by mass: 40-60% of a cement material, 20-33% of fine aggregate, 5-9% of an admixture, 5-8% of an expanding agent, 6.5-9% of an accelerator, 0.5-0.80% of a water reducing agent and 0.5-1.2% of a tackifier, the total mass content is 100%; wherein the accelerator comprises a nucleating agent and aluminum sulfate, and the mass ratio of the nucleating agent to the aluminum sulfate is (0.2-0.4): (1.0-1.4). The prepared cement-based plugging material is short in setting time, high in bonding strength and excellent in micro-expansion dynamic water pressure resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to a dynamic water pressure resistant cement-based plugging material for tunnel maintenance and a preparation method thereof. Background Art

[0002] Tunnels face many serious problems in their long-term operation, among which water leakage is extremely common and has serious consequences. Due to the complex and changeable geological conditions of the tunnel, the surrounding rock fissure water and groundwater can easily penetrate into the tunnel through the tiny gaps and holes in the lining structure under the action of water pressure, causing safety hazards.

[0003] Traditional plugging materials, such as ordinary cement mortar, often show obvious deficiencies when facing dynamic water pressure environments. On the one hand, its bonding strength is limited, and it is difficult to firmly adhere to the leakage site under the impact of water flow. It is easily eroded and peeled off, and cannot effectively block the leakage channel; on the other hand, the anti-seepage performance of ordinary materials is poor, and it cannot withstand the continuously changing dynamic water pressure, and it is easy to leak again. Although some chemical plugging materials have certain effects in the short term, they have problems such as poor durability and poor environmental protection. Over time, they may lose their plugging effect due to aging and decomposition, and may also have a negative impact on the ecological environment around the tunnel.

[0004] In summary, most of the existing plugging materials are difficult to simultaneously take into account the characteristics of high-strength bonding, excellent impermeability and adaptability to changes in dynamic water pressure. There is an urgent need to develop a cement-based plugging material specifically for tunnel maintenance that can effectively resist dynamic water pressure to ensure the stability, durability and operational safety of the tunnel structure. Summary of the invention

[0005] The purpose of the present invention is to provide a cement-based plugging material for tunnel maintenance that resists dynamic water pressure and a preparation method thereof. The prepared cement-based plugging material has a short setting time, high bonding strength, and excellent micro-expansion and dynamic water pressure resistance.

[0006] The present invention adopts the following technical scheme: a tunnel maintenance anti-dynamic water pressure cement-based plugging material, comprising the following raw materials in percentage by mass: 40% to 60% of cement material, 20% to 33% of fine aggregate, 5% to 9% of admixture, 5% to 8% of expansion agent, 6.5% to 9% of accelerator, 0.5% to 0.80% of water reducer and 0.5% to 1.2% of viscosity enhancer; the total mass content is 100%; wherein:

[0007] The accelerating setting agent comprises a crystal nucleating agent and aluminum sulfate, and the mass ratio of the crystal nucleating agent to the aluminum sulfate is: (0.2-0.4): (1.0-1.4).

[0008] Furthermore, the crystal nucleus agent is prepared from sodium silicate, calcium chloride and polycarboxylic acid high-efficiency water reducing agent.

[0009] Further, the tackifier is konjac flour and VAE glue powder, and the mass ratio of the konjac flour and the VAE glue powder is (1.5-2.0):(1.0-1.5);

[0010] Furthermore, the expansion agent is anhydrous gypsum and light-burned magnesium oxide, and the mass ratio of the anhydrous gypsum to the light-burned magnesium oxide is (1-1.5):1.

[0011] Furthermore, the admixture is silica fume and slaked lime, and the mass ratio of the silica fume to slaked lime is 1:(0.8-1).

[0012] Furthermore, the cement material comprises 60%, fine aggregate 20%, silica fume 3.5%, slaked lime 3.5%, anhydrous gypsum 2.5%, light-burned magnesium oxide 2.5%, nucleating agent 2%, aluminum sulfate 5%, water reducing agent 0.3%, konjac flour 0.2%, and VAE glue powder 0.2%.

[0013] The present invention also discloses a method for preparing the above-mentioned anti-dynamic water pressure cement-based plugging material for tunnel maintenance, the preparation method comprising the following steps:

[0014] Step 1: weigh the cement material, fine aggregate, admixture, water reducer and viscosity enhancer according to mass percentage, mix and stir to obtain a dry mixed powder;

[0015] Step 2: prepare a sodium silicate solution and a calcium chloride solution with a concentration of 1 mol / L respectively;

[0016] preparing a crystal nucleating agent;

[0017] The crystal nucleating agent, aluminum sulfate, anhydrous gypsum and light-burned magnesium oxide are mixed and stirred according to mass percentage, and ground into powder to obtain a mixed auxiliary material of an expansion agent and an accelerating setting agent;

[0018] The dry mixed powder and the mixed auxiliary materials are mixed to obtain a dynamic water pressure resistant cement-based plugging material.

[0019] Furthermore, the preparation process of the crystal nucleating agent is as follows: weigh the polycarboxylic acid high-efficiency water reducing agent powder and dissolve it in water to prepare a stabilizer base liquid with a solid content of 1.5%;

[0020] Selecting the sodium silicate solution, calcium chloride solution and stabilizer base solution in a mass ratio of 1:1:1;

[0021] Adding the sodium silicate solution and the calcium chloride solution dropwise into the stabilizer base solution simultaneously, and continuously stirring to obtain a suspension;

[0022] The suspension is treated at 120° C. to 150° C. for 18 to 24 hours, and the solid is collected by filtration to obtain a crystal nucleating agent.

[0023] The beneficial effects of the present invention are as follows: 1. The formation of cement hydration products needs to overcome certain energy barriers to form stable crystal nuclei. The crystal nucleating agent can provide a large number of ready-made nucleation sites for cement hydration. The hydrated ions such as calcium ions and silicate ions generated during the cement hydration process are more likely to aggregate, arrange and crystallize on the surfaces of these crystal nuclei, which greatly reduces the energy barrier required for nucleation and makes the nucleation process more likely to occur; and the addition of the crystal nucleating agent also reduces the inhibition of the growth of hydration products on the surface of cement clinker on the dissolution of C3S, accelerates the dissolution of C3S, and thus accelerates the generation rate of cement hydration products; the crystal nucleating agent is uniformly dispersed in the cement material slurry, and in the process of the growth of the hydration products, they play a supporting role similar to that of a skeleton, guiding the hydration products to grow in an orderly manner on their surfaces, making the arrangement of the generated hydration products such as CSH gel more regular and dense, and improving the mechanical strength of the material; aluminum sulfate can quickly consume calcium ions in the cement system to form a large number of needle-shaped AFt crystals that overlap each other between cement particles, thereby improving the early mechanical properties of the material.

[0024] 2. By mixing anhydrous gypsum with aluminum sulfate in the accelerator as the ettringite expansion source component, and lightly burned magnesium oxide as the magnesium hydroxide expansion source component, the ettringite expansion source is used as the early expansion source and the magnesium hydroxide expansion source is used as the late expansion source to compensate for the volume shrinkage of cement throughout the age; and the entire material expands, and the volume is larger than the original volume of the initial molding material slurry, so that the plugging material has an endogenous expansion source throughout the age, which helps to achieve physical interlocking between the material and the pore wall and resist water pressure.

[0025] 3. Konjac flour and VAE glue powder are mixed as thickeners. Konjac flour can provide adhesion, water retention and filling effects. VAE glue powder continuously forms a continuous film in the slurry, which better bonds cement, aggregate and repair matrix together. The synergistic effect of konjac flour and VAE glue powder prevents the bonding interface from changing due to factors such as drying, thereby ensuring the long-term stability of the material's bonding performance under high water pressure conditions.

[0026] 4. The quick-setting agent can accelerate the hydration reaction, allowing the material to react quickly to form a stone body, so the setting time is extremely short and pressure plugging can be achieved. DETAILED DESCRIPTION

[0027] The present invention is described in detail below through specific implementation modes.

[0028] The invention discloses a hydrodynamic pressure resistant cement-based plugging material for tunnel maintenance, comprising the following raw materials in percentage by mass: 40% to 60% cement material, 20% to 33% fine aggregate, 5% to 9% admixture, 5% to 8% expansion agent, 6.5% to 9% accelerator, 0.5% to 0.80% water reducer and 0.5% to 1.2% viscosity enhancer; the total mass content is 100%; wherein:

[0029] The accelerating setting agent comprises a crystal nucleating agent and aluminum sulfate, and the mass ratio of the crystal nucleating agent to the aluminum sulfate is: (0.2-0.4): (1.0-1.4).

[0030] The crystal nucleus agent is prepared from sodium silicate, calcium chloride and polycarboxylic acid high-efficiency water reducing agent.

[0031] The cement material is formed by mixing ordinary Portland cement with a strength grade of ≥42.5 and double-fast cement, the strength grade of double-fast cement is the same as that of ordinary Portland cement, and the mass ratio of the two is 1:(0.5-2);

[0032] The fine aggregate is quartz sand, and the particle size of the fine aggregate is 70-120 meshes;

[0033] The viscosity enhancer is konjac flour and VAE glue powder, the mass ratio of the konjac flour to the VAE glue powder is (1.5-2.0):(1.0-1.5); the particle size of the konjac flour is 80-120 meshes, and the solid content of the VAE glue powder is ≥98%.

[0034] The expansion agent is anhydrous gypsum and lightly calcined magnesium oxide, and the mass ratio of the anhydrous gypsum to the lightly calcined magnesium oxide is (1-1.5): 1. The calcined magnesium oxide is light magnesium oxide with a calcination temperature of 900°C.

[0035] The admixture is silica fume and slaked lime, and the mass ratio of silica fume to slaked lime is 1:(0.8-1). The silica fume is a gray powder with a SiO2 content of 98%; the slaked lime is a 200-mesh industrial grade white powder with an effective component of 90%.

[0036] The cement material comprises 60%, fine aggregate 20%, silica fume 3.5%, slaked lime 3.5%, anhydrous gypsum 2.5%, light-burned magnesium oxide 2.5%, nucleating agent 2%, aluminum sulfate 5%, water reducing agent 0.3%, konjac flour 0.2% and VAE glue powder 0.2%.

[0037] The present invention also discloses a method for preparing the above-mentioned anti-dynamic water pressure cement-based plugging material for tunnel maintenance, the preparation method comprising the following steps:

[0038] Step 1: weigh the cement material, fine aggregate, admixture, water reducer and viscosity enhancer according to mass percentage, mix and stir to obtain a dry mixed powder;

[0039] Step 2: prepare a sodium silicate solution and a calcium chloride solution with a concentration of 1 mol / L respectively;

[0040] preparing a crystal nucleating agent;

[0041] The crystal nucleating agent, aluminum sulfate, anhydrous gypsum and light-burned magnesium oxide are mixed and stirred for 30 minutes, and then ground into a uniform powder, and passed through a 200-mesh sieve to obtain a mixed auxiliary material of an expansion agent and an accelerating setting agent;

[0042] The dry mixed powder and the mixed auxiliary materials are mixed and stirred for 30 minutes to obtain a dynamic water pressure resistant cement-based plugging material.

[0043] The preparation process of the crystal nucleating agent is as follows: weigh the polycarboxylic acid high-efficiency water reducing agent powder and dissolve it in water to prepare a stabilizer base liquid with a solid content of 1.5%;

[0044] Slowly add the sodium silicate solution and the calcium chloride solution into the stabilizer base solution at the same rate, and the volume ratio of the sodium silicate solution, the calcium chloride solution and the stabilizer base solution is 1:1:1;

[0045] The sodium silicate solution and the calcium chloride solution are simultaneously added dropwise to the stabilizer base solution. The mixed solution needs to be stirred continuously during the addition process. After the mixing is completed, the stirring needs to be continued for 3 days to obtain a stable suspension;

[0046] The suspension is treated at 120° C. to 150° C. for 18 to 24 hours, and the solid product is collected by filtration. After being washed with deionized water for several times, the solid product is dried at 50° C. to 70° C. to obtain a crystal nucleating agent.

[0047] Example 1

[0048] Taking the preparation of 100g of an anti-dynamic water pressure cement-based plugging material for tunnel maintenance in the present invention as an example, the raw materials include the following weights: 30g of ordinary Portland cement, 30g of double-fast cement, 20g of fine aggregate, 2.5g of silica fume, 2.5g of slaked lime, 2.5g of anhydrous gypsum, 2.5g of light-burned magnesium oxide, 2g of nucleating agent, 7g of aluminum sulfate, 0.5g of water reducing agent, 0.3g of konjac flour, and 0.2g of VAE glue powder.

[0049] The preparation method of the above-mentioned anti-dynamic water pressure cement-based plugging material for tunnel maintenance comprises the following steps:

[0050] Step 1: Mix and stir ordinary Portland cement, double-fast cement, fine aggregate, silica fume, slaked lime, water reducing agent, konjac flour and VAE glue powder to obtain a dry mixed powder;

[0051] Step 2: Weigh the polycarboxylate high-efficiency water-reducing agent powder and dissolve it in water to prepare a stabilizer base liquid with a solid content of 1.5%;

[0052] Slowly add the sodium silicate solution and the calcium chloride solution into the stabilizer base solution at the same rate, and the volume ratio of the sodium silicate solution, the calcium chloride solution and the stabilizer base solution is 1:1:1;

[0053] The sodium silicate solution and the calcium chloride solution are simultaneously added dropwise to the stabilizer base solution. The mixed solution needs to be stirred continuously during the addition process. After the mixing is completed, the stirring needs to be continued for 3 days to obtain a stable suspension;

[0054] The suspension is treated at 120° C. to 150° C. for 18 to 24 hours, and the solid product is collected by filtration. After being washed with deionized water for several times, the solid product is dried at 50° C. to 70° C. to obtain a crystal nucleating agent.

[0055] The crystal nucleating agent, aluminum sulfate, anhydrous gypsum and lightly calcined magnesium oxide are mixed and stirred for 30 minutes, then ground into a uniform powder, and passed through a 200-mesh sieve to obtain a mixed auxiliary material of an expansion agent and an accelerating setting agent;

[0056] The dry mixed powder and the mixed auxiliary materials are mixed and stirred for 30 minutes to obtain a dynamic water pressure resistant cement-based plugging material.

[0057] Example 2

[0058] Taking the preparation of 100g of an anti-dynamic water pressure cement-based plugging material for tunnel maintenance in the present invention as an example, the raw materials include the following weights: 20g of ordinary Portland cement, 20g of double-fast cement, 33g of fine aggregate, 5g of silica fume, 4g of slaked lime, 4.8g of anhydrous gypsum, 3.2g of light-burned magnesium oxide, 2g of nucleating agent, 7g of aluminum sulfate, 0.5g of water reducing agent, 0.3g of konjac flour, and 0.2g of VAE glue powder.

[0059] In this embodiment, the preparation method of a dynamic water pressure resistant cement-based plugging material for tunnel maintenance is the same as that in Embodiment 1.

[0060] Example 3

[0061] Taking the preparation of 100g of an anti-dynamic water pressure cement-based plugging material for tunnel maintenance in the present invention as an example, the raw materials include the following weights: 20g of ordinary Portland cement, 40g of double-fast cement, 20g of fine aggregate, 5g of silica fume, 4g of slaked lime, 4.8g of anhydrous gypsum, 3.2g of light-burned magnesium oxide, 2g of nucleating agent, 7g of aluminum sulfate, 0.5g of water reducing agent, 0.3g of konjac flour, and 0.2g of VAE glue powder.

[0062] In this embodiment, the preparation method of a dynamic water pressure resistant cement-based plugging material for tunnel maintenance is the same as that in Embodiment 1.

[0063] Example 4

[0064] Taking the preparation of 100g of a tunnel maintenance anti-dynamic water pressure cement-based plugging material in the present invention as an example, the raw materials include the following weights: 30g of ordinary Portland cement, 15g of double-fast cement, 30g of fine aggregate, 3.5g of silica fume, 3.5g of slaked lime, 4g of anhydrous gypsum, 4g of light-burned magnesium oxide, 1g of nucleating agent, 7g of aluminum sulfate, 0.8g of water reducing agent, 0.8g of konjac flour, and 0.4g of VAE glue powder.

[0065] In this embodiment, the preparation method of a dynamic water pressure resistant cement-based plugging material for tunnel maintenance is the same as that in Embodiment 1.

[0066] Example 5

[0067] Taking the preparation of 100g of an anti-dynamic water pressure cement-based plugging material for tunnel maintenance in the present invention as an example, the raw materials include the following weights: 27.5g of ordinary Portland cement, 27.5g of double-fast cement, 25g of fine aggregate, 2.5g of silica fume, 2.5g of slaked lime, 3.5g of anhydrous gypsum, 3.5g of light-burned magnesium oxide, 1g of nucleating agent, 5.5g of aluminum sulfate, 0.5g of water reducing agent, 0.5g of konjac flour, and 0.5g of VAE glue powder.

[0068] In this embodiment, the preparation method of a dynamic water pressure resistant cement-based plugging material for tunnel maintenance is the same as that in Embodiment 1.

[0069] In order to verify the influence of various raw materials on the performance of cement-based plugging material in a cement-based plugging material for tunnel maintenance of the present invention, the following comparative examples are given:

[0070] Comparative Example 1

[0071] Taking the preparation of 100g product as an example, it is prepared from the following raw materials by weight: 21.5g of ordinary Portland cement, 21.5g of double-fast cement, 33g of fine aggregate, 5g of silica fume, 4g of slaked lime, 1g of anhydrous gypsum, 4g of light-burned magnesium oxide, 2g of nucleating agent, 7g of aluminum sulfate, 0.5g of water reducing agent, 0.3g of konjac flour, and 0.2g of VAE glue powder. The above materials are prepared according to the preparation method of the present invention to obtain a product.

[0072] Comparative Example 2

[0073] Taking the preparation of 100g product as an example, it is prepared from the following raw materials by weight: 30g of ordinary Portland cement, 30g of double-fast cement, 22g of fine aggregate, 2.5g of silica fume, 2.5g of slaked lime, 2.5g of anhydrous gypsum, 2.5g of light-burned magnesium oxide, 7g of aluminum sulfate, 0.5g of water reducer, 0.3g of konjac flour, and 0.2g of VAE glue powder. The above materials are prepared according to the preparation method of the anti-dynamic water pressure cement-based plugging material for tunnel maintenance.

[0074] Comparative Example 3

[0075] Taking the preparation of 100g product as an example, it is prepared from the following raw materials by weight: 30g ordinary Portland cement, 20g double-fast cement, 30g fine aggregate, 3.5g silica fume, 3.5g slaked lime, 4g anhydrous gypsum, 4g light-burned magnesium oxide, 1g nucleating agent, 2g aluminum sulfate, 0.8g water reducing agent, 0.8g konjac flour, and 0.4g VAE glue powder.

[0076] Comparative Example 4

[0077] Taking the preparation of 100g product as an example, it is prepared from the following raw materials by weight: 28g ordinary Portland cement, 28g double-fast cement, 25g fine aggregate, 2.5g silica fume, 2.5g slaked lime, 3.5g anhydrous gypsum, 3.5g light-burned magnesium oxide, 1g nucleating agent, 5.5g aluminum sulfate, and 0.5g water reducer.

[0078] In Comparative Examples 1 to 4, the preparation methods of the products are based on the preparation method of a cement-based leak-proof material for tunnel maintenance resistant to dynamic water pressure of the present invention. In each step, if a raw material is missing, the preparation process involved in the missing raw material is reduced accordingly.

[0079] Performance comparison test:

[0080] With reference to GB 23440-2009 "Inorganic waterproof plugging material", various properties of Examples 1 to 5 and Comparative Examples 1 to 4 were tested. The mass ratio of the dynamic water pressure resistant cement-based plugging material for tunnel maintenance to water was 1:0.27, and the test stirring time was 20s. Table 1 below shows the test results of various properties.

[0081] Table 1 Performance test results of various embodiments and comparative examples

[0082]

[0083] It can be seen from the performance results of Example 4, Example 3, Example 2 and Example 1 that appropriately increasing the proportion of double-fast cement is beneficial to shortening the setting time of the material and improving the early mechanical properties of the material.

[0084] It can be seen from the performance results of Comparative Example 1 and Example 2 that anhydrous gypsum can react with aluminum sulfate to generate expansive Aft, thereby increasing the early expansion rate of the material, while lightly burned magnesium oxide ensures the continuous increase of the later expansion rate of the material, which can effectively compensate for the shrinkage of cement materials throughout their age, and at the same time ensure that the dynamic water pressure-resistant cement-based plugging material for tunnel maintenance has expansion characteristics, forms a strong expansion extrusion force and friction force with the concrete matrix when plugging water leakage, can prevent water from leaking into the structure from weak points, and resist the lateral thrust generated by the dynamic water pressure, preventing the material and the concrete matrix from relative displacement.

[0085] From the performance results of Comparative Example 2 and Example 1, it can be seen that the nucleating agent provides nucleation sites for cement hydration and reduces the nucleation barrier. On the one hand, it accelerates the formation of cement hydration products, and on the other hand, it reduces the inhibition of the growth of hydration products on the surface of cement clinker on the dissolution of C3S, thereby accelerating the dissolution of C3S; the nucleating agent is beneficial to shorten the setting time and improve the early strength of the material. From the performance results of Comparative Example 3 and Example 4, it can be seen that aluminum sulfate can quickly consume calcium ions in the cement system, forming a large number of needle-shaped AFt crystals that overlap each other between cement particles, thereby improving the early mechanical properties of the material. Nucleating agents and aluminum sulfate are key components to ensure the rapid setting of materials.

[0086] It can be known from the performance results of Comparative Example 4, Example 5 and Example 1 that konjac flour and VAE glue powder are used, and konjac flour can provide adhesion, water retention and filling effects, and VAE glue powder continuously forms a continuous film in the slurry, and cement, aggregate and repair matrix are better bonded together; Konjac flour and VAE glue powder synergistically prevent the bonding interface from changing due to factors such as drying, thereby ensuring the long-term stability of the material bonding performance. Konjac flour and VAE glue powder can improve the material bonding performance, and VAE glue powder improves the effect better. Adding tackifier in the material can prolong the setting time of the material to a certain extent and reduce the mechanical properties.

Claims

1. A cement-based plugging material for tunnel maintenance that resists dynamic water pressure, characterized in that: The raw materials include the following mass percentages: cement material 40% to 60%, fine aggregate 20% to 33%, admixture 5% to 9%, expansion agent 5% to 8%, accelerator 6.5% to 9%, water reducer 0.5% to 0.80% and viscosity enhancer 0.5% to 1.2%; the total mass content is 100%; wherein: The accelerating setting agent comprises a crystal nucleating agent and aluminum sulfate, and the mass ratio of the crystal nucleating agent to the aluminum sulfate is: (0.2-0.4): (1.0-1.4).

2. The anti-dynamic water pressure cement-based plugging material for tunnel maintenance according to claim 1, characterized in that: The crystal nucleus agent is prepared from sodium silicate, calcium chloride and polycarboxylic acid high-efficiency water reducing agent.

3. The anti-dynamic water pressure cement-based plugging material for tunnel maintenance according to claim 2, characterized in that: The viscosity enhancers are konjac flour and VAE glue powder, and the mass ratio of the konjac flour to the VAE glue powder is (1.5-2.0):(1.0-1.5).

4. The anti-dynamic water pressure cement-based plugging material for tunnel maintenance as claimed in claim 3, characterized in that: The expansion agent is anhydrous gypsum and light-burned magnesium oxide, and the mass ratio of the anhydrous gypsum to the light-burned magnesium oxide is (1-1.5):

1.

5. The anti-dynamic water pressure cement-based plugging material for tunnel maintenance as claimed in claim 4, characterized in that: The admixtures are silica fume and slaked lime, and the mass ratio of the silica fume to slaked lime is 1:(0.8-1).

6. The anti-dynamic water pressure cement-based plugging material for tunnel maintenance according to claim 5, characterized in that: The cement material comprises 60%, fine aggregate 20%, silica fume 3.5%, slaked lime 3.5%, anhydrous gypsum 2.5%, light-burned magnesium oxide 2.5%, nucleating agent 2%, aluminum sulfate 5%, water reducing agent 0.3%, konjac flour 0.2% and VAE glue powder 0.2%.

7. A method for preparing a cement-based leak-proof material for tunnel maintenance resistant to dynamic water pressure according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: Step 1: weigh the cement material, fine aggregate, admixture, water reducer and viscosity enhancer according to mass percentage, mix and stir to obtain a dry mixed powder; Step 2: prepare a sodium silicate solution and a calcium chloride solution with a concentration of 1 mol / L respectively; preparing a crystal nucleating agent; The crystal nucleating agent, aluminum sulfate, anhydrous gypsum and light-burned magnesium oxide are mixed and stirred according to mass percentage, and ground into powder to obtain a mixed auxiliary material of an expansion agent and an accelerating setting agent; The dry mixed powder and the mixed auxiliary materials are mixed to obtain a dynamic water pressure resistant cement-based plugging material.

8. The method for preparing a cement-based leak-proof material for tunnel maintenance according to claim 7, characterized in that: The preparation process of the crystal nucleating agent is as follows: weigh the polycarboxylic acid high-efficiency water reducing agent powder and dissolve it in water to prepare a stabilizer base liquid with a solid content of 1.5%; Selecting the sodium silicate solution, calcium chloride solution and stabilizer base solution in a mass ratio of 1:1:1; Adding the sodium silicate solution and the calcium chloride solution dropwise into the stabilizer base solution simultaneously, and continuously stirring to obtain a suspension; The suspension is treated at 120° C. to 150° C. for 18 to 24 hours, and the solid is collected by filtration to obtain a crystal nucleating agent.

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