High-toughness and high-durability TBM (Tunnel Boring Machine) behind-wall gravel grouting material and preparation method thereof

Abstract

The invention relates to the technical field of constructional engineering, in particular to a high-toughness and high-durability TBM (Tunnel Boring Machine) behind-wall gravel grouting material and a preparation method thereof. The invention relates to a high-toughness and high-durability TBM (Tunnel Boring Machine) behind-wall gravel grouting material, which is prepared from the following raw materials in parts by weight: 800 to 1000 parts of fine sand, 30 to 50 parts of bentonite, 100 to 200 parts of fly ash, 400 to 600 parts of Portland cement, 70 to 100 parts of gypsum, 70 to 100 parts of modified rubber particles, 5 to 10 parts of early strength agent and 400 to 600 parts of water, a hydroxyl group and a sulfur group are grafted on the modified rubber particles. The high-toughness and high-durability TBM wall back gravel grouting material disclosed by the invention has excellent toughness and aging resistance.

Description

Technical Field

[0001] The present application relates to the technical field of construction engineering, and more specifically, to a high-toughness and high-durability TBM wall behind-the-wall crushed stone grouting material and a preparation method thereof. Background Art

[0002] In recent years, the number of tunnel construction cases using the shield method has gradually increased in my country. Many tunnel projects are located in high-intensity earthquake zones, and shield tunnels are susceptible to varying degrees of damage under strong earthquakes. However, due to the complex location of the tunnels, tunnel repair work is also difficult to carry out. Therefore, in order to improve the safety of tunnels under strong earthquakes, it is necessary to carry out research on shock-absorbing technology for shield tunnels.

[0003] Synchronous grouting is a key link in shield tunnel construction, and the selection of grouting materials is also crucial. In this regard, the applicant considered adding rubber particles to the grouting material to improve the toughness of the grouting material through the buffering effect of the rubber particles, thereby obtaining an extremely good shock-absorbing effect. However, due to the weak bonding in the interface transition zone formed between the rubber particles and the grouting material matrix, the toughness of the grouting material still needs to be improved. Summary of the invention

[0004] In order to improve the defect that the toughness of the grouting material is still insufficient due to the presence of an interface between rubber particles and the grouting material, the present application provides a high-toughness and high-durability TBM wall behind-the-wall gravel grouting material and a preparation method thereof.

[0005] In the first aspect, the present application provides a high-toughness and high-durability TBM wall behind-the-wall crushed stone grouting material, which adopts the following technical solution: A high-toughness and high-durability TBM wall behind-the-wall crushed stone grouting material comprises the following raw materials in parts by weight: 800-1000 parts of fine sand, 30-50 parts of bentonite, 100-200 parts of fly ash, 400-600 parts of Portland cement, 70-100 parts of gypsum, 70-100 parts of modified rubber particles, 5-10 parts of early strength agent and 400-600 parts of water; the modified rubber particles are grafted with hydroxyl groups and sulfide groups.

[0006] Preferably, the preparation method of the modified rubber particles is: First, the rubber particles are soaked in a 5% sodium hydroxide solution for 20-30 hours, and then washed with water, and then added into a 5% potassium permanganate solution, and the pH value of the solution is adjusted to 2-3 by sulfuric acid; then, the solution is heated to 50-70°C, and the oxidation reaction is stirred for 1-3 hours. During this period, the pH value is always controlled to be maintained at 2-3 by 5% potassium permanganate solution and sulfuric acid, and then washed with water, and finally the rubber particles are soaked in a sodium bisulfite solution for 1-2 hours, the soaking temperature is 50-70°C, and finally dried to obtain modified rubber particles.

[0007] In the present application, the surface of the rubber particles is modified by oxidant sulfonation, so that a large number of hydroxyl groups, carbon groups and sulfonic acid groups are introduced into the surface of the rubber particles. The introduction of these polar groups significantly improves the hydrophilicity of the rubber, improves the interface relationship between the rubber and the cement, and further promotes a significant increase in the bonding strength between the rubber and the cement, further improving the toughness of the crushed stone grouting material behind the TBM wall.

[0008] Preferably, the rubber particles include the following raw materials in parts by weight: 90-110 parts of styrene-butadiene rubber, 4-6 parts of zinc oxide, 1-3 parts of stearic acid, 1-3 parts of sulfur and 1-2 parts of anti-aging accelerator, wherein the anti-aging accelerator is attapulgite loaded with 2-mercaptobenzimidazole derivatives, and the anti-aging accelerator contains selenide and promoting groups.

[0009] Although the addition of rubber particles can effectively improve the toughness of the crushed stone grouting material behind the TBM wall, due to the existence of factors such as tunnel vibration and climate, the crushed stone grouting material behind the TBM wall will continue to be subjected to thermal oxidative aging, which will cause the toughness of the crushed stone grouting material behind the TBM wall to decrease after long-term use.

[0010] 2-Mercaptobenzimidazole derivatives can prevent rubber from aging. The mechanism is that 2-mercaptobenzimidazole derivatives can react with free radicals in rubber molecules, thereby neutralizing the free radicals and stabilizing the rubber molecules to prevent further oxidation and decomposition. At the same time, 2-mercaptobenzimidazole derivatives can also maintain good anti-aging properties in high temperature and humid environments.

[0011] Selenides can form stable chemical bonds with rubber molecules, thereby improving the intermolecular interactions between rubber and other components, and further improving the mechanical properties, aging resistance and electrical conductivity of rubber products. When used in combination with 2-mercaptobenzimidazole derivatives, the prepared rubber products will have better aging resistance.

[0012] In addition, the introduction of hydroxyl and sulfide groups requires oxidation treatment of the surface of the rubber particles, and the presence of 2-mercaptobenzimidazole derivatives will limit the occurrence of oxidation. The surface of attapulgite contains a large number of pores, which can load 2-mercaptobenzimidazole derivatives, thereby achieving a sustained release effect, reducing the impact of 2-mercaptobenzimidazole derivatives when modifying the rubber particles, and also serving the purpose of anti-aging when the grouting material is used later.

[0013] Preferably, the promoting group is a dithiocarbamate group.

[0014] Although selenides can react with double bonds in rubber to form cross-linked structures like sulfides, and even have better aging resistance and stability, the vulcanization rate of selenides is slower than that of sulfides. The introduction of dithiocarbamic acid groups can exist as auxiliary accelerators, thereby accelerating the vulcanization process of rubber.

[0015] Specifically, the dithiocarbamic acid group molecule contains two interacting sulfide bonds. During the vulcanization process, the two sulfide bonds are broken first, and one sulfur atom reacts with the hydrogen atoms in the rubber molecule to form thiol, and the other sulfur atom reacts with the hydrogen atoms in another rubber molecule to form disulfide. Finally, the thiol and disulfide react with hydrogen atoms to form vulcanized rubber.

[0016] Preferably, the preparation method of the anti-aging accelerator is: Dissolve 3-5g 2-mercaptobenzimidazole-selenide in 20-40ml anhydrous ethanol, then add 18-22ml ethanol-water mixture containing 0.7-0.9g caustic soda, the mass ratio of the two in the ethanol-water mixture is 1:1, stir at room temperature until clear, and then cool the solution to 0°C, then add 5-6ml carbon disulfide-ethanol solution at a rate of 2s / drop, the volume ratio of carbon disulfide to ethanol is 15:100, after the addition is completed, continue to stir for 20-40min, finally add 2-3ml 4-methylpiperidine, then let stand for 5-10min, and then add 50ml iodine-potassium iodide aqueous solution at a rate of 1s / drop, the concentration of iodine is 50.8g / L, the concentration of potassium iodide is 50g / L, after the addition is completed, add 4-8g attapulgite and continue to stir for 1-2h, finally filter, wash, filter and dry to obtain an aging-resistant accelerator.

[0017] Preferably, the preparation method of the 2-mercaptobenzimidazole-selenide is: at room temperature, dissolve 2-4g 2-mercaptobenzimidazole in 150-250ml anhydrous ethanol, continue stirring until clear, and then slowly add 15-25ml selenium dioxide-anhydrous ethanol solution, the concentration of selenium dioxide-anhydrous ethanol solution is 0.05g / ml, the dropping speed is 2s / drop, the reaction temperature is controlled at 40-60°C, and after the dropwise addition is completed, stirring is continued for 1-2h, and finally filtered, washed, suction filtered and dried to obtain 2-mercaptobenzimidazole-selenide.

[0018] Preferably, the preparation method of the rubber particles is: The styrene butadiene rubber is plasticized in an internal mixer, and after being evenly mixed, the styrene butadiene rubber is transferred to a double-roll mill for processing. During the processing, zinc oxide, stearic acid, an anti-aging accelerator and sulfur are added one by one, and are fully mixed after each addition. Cutting, rolling, extrusion and degassing are continuously performed during the mixing process. After the mixing is completed, the styrene butadiene rubber compound is left to stand in a dry environment for 20-30 hours, and finally pelletized to obtain rubber particles.

[0019] In the second aspect, the present application provides a method for preparing a high-toughness and high-durability TBM wall behind-the-wall crushed stone grouting material, which adopts the following technical solution: A method for preparing a high-toughness and high-durability TBM wall back-end crushed stone grouting material is as follows: Add fine sand, bentonite, fly ash, silicate cement, gypsum, modified rubber particles, early strength agent and water into the mortar mixer and mix for 2-5 minutes. Then set the grouting pressure to 0.4-0.8MPa, control the flow rate at 50-120L / min, and use four points of shield tail for simultaneous grouting, with the upper and lower ratio of 6.5:3.5 and the injection rate of 125-150%.

[0020] In summary, this application has the following beneficial effects: 1. In the present application, the surface of the rubber particles is modified by sulfonation with an oxidant, so that a large number of hydroxyl groups, carbon groups and sulfonic acid groups are introduced into the surface of the rubber particles. The introduction of these polar groups significantly improves the hydrophilicity of the rubber, improves the interface relationship between the rubber and the cement, and further promotes a significant increase in the bonding strength between the rubber and the cement, further improving the toughness of the crushed stone grouting material behind the TBM wall.

[0021] 2. Although the addition of rubber particles can effectively improve the toughness of the crushed stone grouting material behind the TBM wall, due to the existence of factors such as tunnel vibration and climate, the crushed stone grouting material behind the TBM wall will continue to be aged by thermal oxidation, which will cause the toughness of the crushed stone grouting material behind the TBM wall to decrease after long-term use; 2-Mercaptobenzimidazole derivatives can prevent the aging of rubber. The mechanism is that 2-Mercaptobenzimidazole derivatives can react with free radicals in rubber molecules, thereby neutralizing the free radicals and stabilizing the rubber molecules to prevent further oxidation and decomposition. At the same time, 2-Mercaptobenzimidazole derivatives can also maintain good anti-aging properties in high temperature and humid environments. Selenides can form stable chemical bonds with rubber molecules, thereby improving the intermolecular interactions between rubber and other components, and further improving the mechanical properties, aging resistance and electrical conductivity of rubber products. When used in combination with 2-mercaptobenzimidazole derivatives, the prepared rubber products will have better aging resistance.

[0022] Since the introduction of hydroxyl and sulfide groups requires oxidation treatment of the surface of the rubber particles, the presence of 2-mercaptobenzimidazole derivatives will limit the occurrence of oxidation. The surface of attapulgite contains a large number of pores, which can load 2-mercaptobenzimidazole derivatives, thereby achieving a sustained release effect, reducing the impact of 2-mercaptobenzimidazole derivatives when modifying the rubber particles, and at the same time, it can also serve the purpose of anti-aging when the grouting material is used later.

[0023] 4. Although selenide can react with double bonds in rubber to form a cross-linked structure like sulfide, and even has better aging resistance and stability, the vulcanization speed of selenide is slower than that of sulfide. The introduction of dithiocarbamic acid groups can exist as an auxiliary accelerator, thereby accelerating the vulcanization process of rubber; Specifically, the dithiocarbamic acid group molecule contains two interacting sulfide bonds. During the vulcanization process, the two sulfide bonds are broken first, and one sulfur atom reacts with the hydrogen atoms in the rubber molecule to form thiol, and the other sulfur atom reacts with the hydrogen atoms in another rubber molecule to form disulfide. Finally, the thiol and disulfide react with hydrogen atoms to form vulcanized rubber. DETAILED DESCRIPTION

[0024] The present application is further described in detail below in conjunction with Examples 1-6 and Comparative Example 1.

[0025] Fine sand CAS: 14808-60-7; Bentonite CAS: 1302-78-9; Fly ash grade II; Portland cement CAS: 1327-39-5; Gypsum CAS: 10101-41-4; Early strength agent Xinzhiyuan Chemical Calcium Formate; Attapulgite CAS: 1337-76-4; Potassium iodide, zinc oxide, stearic acid, and sulfur were all purchased from Dongguan Foster Rubber; Styrene butadiene rubber SBR1502 Dongguan Siqi Rubber; Sodium hydroxide, potassium permanganate, sulfuric acid, ethanol, caustic soda, iodine, potassium iodide, sodium bisulfite, 2-mercaptobenzimidazole, selenium dioxide, and carbon disulfide were all purchased from Shanghai MacLean Biochemical Technology.

[0026] A high-toughness and high-durability TBM wall back-end crushed stone grouting material includes the following raw materials: 900kg fine sand, 40kg bentonite, 150kg fly ash, 500kg Portland cement, 90kg gypsum, 80kg modified rubber particles, 7kg early strength agent and 500kg water.

[0027] The preparation method of high-toughness and high-durability crushed stone grouting material behind the TBM wall is as follows: add fine sand, bentonite, fly ash, silicate cement, gypsum, modified rubber particles, early strength agent and water into a mortar mixer, and mix for 4 minutes; then set the grouting pressure to 0.6MPa, control the flow rate at 100L / min, and use four points of the shield tail for simultaneous grouting, with a ratio of 6.5:3.5 between the upper and lower parts, and an injection rate of 125-150%.

[0028] The modified rubber particles are grafted with hydroxyl groups and sulfide groups. The preparation method of the modified rubber particles is as follows: First, the rubber particles are immersed in a 5% sodium hydroxide solution for 24 hours, and then washed with water, and then added into a 5% potassium permanganate solution, and the pH value of the solution is adjusted to 3 by sulfuric acid; then, the solution is heated to 60°C and stirred for oxidation reaction for 2 hours. During this period, the pH value is always controlled to be maintained at 3 by 5% potassium permanganate solution and sulfuric acid, and then washed with water. Finally, the rubber particles are immersed in a sodium bisulfite solution for 2 hours, the immersion temperature is 60°C, and finally dried to obtain modified rubber particles.

[0029] The rubber particles include the following raw materials: 100g styrene-butadiene rubber, 5g zinc oxide, 2g stearic acid and 2g sulfur.

[0030] The preparation method of rubber particles is as follows: plasticizing styrene butadiene rubber in an internal mixer, transferring the styrene butadiene rubber to a double-roll mill for processing after mixing evenly, adding zinc oxide, stearic acid and sulfur one by one during the processing, and fully mixing after each addition, and continuously cutting, rolling, extruding and degassing during the mixing process; after mixing, the styrene butadiene rubber compound is left to stand in a dry environment for 24 hours, and finally pelletizing to obtain rubber particles.

[0031] The difference from Example 1 is that the rubber particles include the following raw materials: 100 g of styrene-butadiene rubber, 5 g of zinc oxide, 2 g of stearic acid, 2 g of sulfur and 1.5 g of anti-aging accelerator.

[0032] The preparation method of rubber particles is as follows: plasticizing styrene butadiene rubber in an internal mixer, transferring the styrene butadiene rubber to a double-roll mill for processing after mixing evenly, adding zinc oxide, stearic acid, sulfur and anti-aging accelerator one by one during the processing, and fully mixing after each addition, and continuously cutting, rolling, extruding and degassing during the mixing process; after the mixing is completed, the styrene butadiene rubber compound is left to stand in a dry environment for 24 hours, and finally pelletized to obtain rubber particles.

[0033] The anti-aging accelerator contains 2-mercaptobenzimidazole derivatives and selenide. The preparation method of the anti-aging accelerator is as follows: At room temperature, 3g 2-mercaptobenzimidazole was dissolved in 200ml anhydrous ethanol, and stirring was continued until it was clear. Then 20ml selenium dioxide-anhydrous ethanol solution was slowly added dropwise. The concentration of selenium dioxide-anhydrous ethanol solution was 0.05g / ml. The dropping speed was 2s / drop. The reaction temperature was controlled at 50°C. After the addition was completed, stirring was continued for 2h. Finally, the solution was filtered, washed, filtered and dried to obtain an anti-aging promoter.

[0034] The difference from Example 2 is that the anti-aging agent is attapulgite loaded with 2-mercaptobenzimidazole derivatives, and the anti-aging agent contains selenide.

[0035] The preparation method of the anti-aging accelerator is as follows: At room temperature, 3g 2-mercaptobenzimidazole was dissolved in 200ml anhydrous ethanol, and stirring was continued until it was clear. Then 20ml selenium dioxide-anhydrous ethanol solution was slowly added dropwise, and the concentration of selenium dioxide-anhydrous ethanol solution was 0.05g / ml. The dropping speed was 2s / drop, and the reaction temperature was controlled at 50°C. After the addition was completed, 6g attapulgite was added, and stirring was continued for 2h. Finally, it was filtered, washed, and dried to obtain an anti-aging promoter.

[0036] The difference from Example 3 is that the anti-aging accelerator further contains a dithiocarbamic acid group.

[0037] The preparation method of the anti-aging accelerator is as follows: Dissolve 4g of 2-mercaptobenzimidazole-selenide in 30ml of anhydrous ethanol, then add 120ml of ethanol-water mixture containing 0.8g of caustic soda, the mass ratio of the two in the ethanol-water mixture is 1:1, stir at room temperature until clear, and then cool the solution to 0°C, then add 6ml of carbon disulfide-ethanol solution at a rate of 2s / drop, the volume ratio of carbon disulfide to ethanol is 15:100, after the addition is completed, continue to stir for 30min, finally add 3ml of 4-methylpiperidine, then let stand for 8min, and then add 50ml of iodine-potassium iodide aqueous solution at a rate of 1s / drop, the concentration of iodine is 50.8g / L, the concentration of potassium iodide is 50g / L, after the addition is completed, add 6g of attapulgite and continue to stir for 2h, finally filter, wash, filter and dry to obtain an aging-resistant accelerator.

[0038] The preparation method of 2-mercaptobenzimidazole-selenide is: At room temperature, 3g 2-mercaptobenzimidazole was dissolved in 200ml anhydrous ethanol, and the mixture was stirred continuously until it became clear. Then, 20ml selenium dioxide-anhydrous ethanol solution was slowly added dropwise, and the concentration of selenium dioxide-anhydrous ethanol solution was 0.05g / ml. The addition rate was 2s / drop. The reaction temperature was controlled at 50°C. After the addition was completed, stirring was continued for 2h. Finally, the mixture was filtered, washed, and dried to obtain 2-mercaptobenzimidazole-selenide.

[0039] The difference from Example 4 is that the addition amounts of the components of the high-toughness and high-durability TBM wall behind-the-wall crushed stone grouting material are different, as specifically shown in Table 1.

[0040] Table 1 Addition amount of each component of high toughness and high durability TBM wall crushed stone grouting material in Examples 4 to 6 The difference from Example 1 is that the surface of the rubber particles is no longer modified, that is, there are no hydroxyl groups and sulfide groups on the surface of the rubber particles.

[0041] 1. Compressive strength test Three samples were taken from Examples 1 to 6 and Comparative Example 1, and the compressive strength of the samples was tested according to GB / T50123-2019 "Test Procedure for Geotechnical Engineering" to obtain the 7-day compressive strength and take the average value.

[0042] 2. Aging resistance test Three samples were taken out from Examples 1 to 6 and Comparative Example 1, respectively, and then placed in an M115 thermal oxidation aging box with an aging temperature of 100°C and an aging time of 24 hours. The compressive strength of the samples after aging was then tested again with reference to GB / T50123-2019 "Test Procedure for Geotechnical Engineering", and the change in compressive strength was finally calculated.

[0043] Change in compressive strength = (compressive strength at 7 days - compressive strength at 7 days after aging) / compressive strength at 7 days × 100%.

[0044] The test data are shown in Table 2.

[0045] Table 2 Test data table of Example 1 to Example 6 and Comparative Example 1 Referring to Example 1 and Comparative Example 1 and in combination with Table 2, it can be seen that, relative to Comparative Example 1, the 7-day compressive strength of Example 1 is significantly improved, but the change in compressive strength is also significantly increased, which shows that the introduction of hydroxyl and sulfide groups can effectively improve the toughness of the TBM behind-the-wall crushed stone grouting material, but will also affect the aging resistance of the TBM behind-the-wall crushed stone grouting material.

[0046] The reason is that, in the present application, the surface of the rubber particles is modified by oxidant sulfonation, so that a large number of hydroxyl groups, carbon groups and sulfonic acid groups are introduced into the surface of the rubber particles. The introduction of these polar groups significantly improves the hydrophilicity of the rubber, improves the interface relationship between the rubber and the cement, and then significantly improves the bonding strength between the rubber and the cement, further improving the toughness of the crushed stone grouting material behind the TBM wall.

[0047] But at the same time, the oxidation modification method also changes the internal structure of the rubber particles in the crushed stone grouting material behind the TBM wall, thereby accelerating the aging of the rubber particles and affecting the durability of the crushed stone grouting material behind the TBM wall.

[0048] Referring to Example 1 and Example 2 and combining with Table 2, it can be seen that, relative to Example 1, the 7-day compressive strength of Example 2 is significantly improved, and at the same time, the change in compressive strength of Example 2 is also significantly reduced, which shows that the use of the anti-aging accelerator can improve the durability of the crushed stone grouting material behind the TBM wall while effectively improving the toughness of the crushed stone grouting material behind the TBM wall.

[0049] The reason is that 2-mercaptobenzimidazole derivatives can prevent rubber from aging. The mechanism is that 2-mercaptobenzimidazole derivatives can react with free radicals in rubber molecules, thereby neutralizing the free radicals and stabilizing the rubber molecules to prevent further oxidation and decomposition. At the same time, 2-mercaptobenzimidazole derivatives can also maintain good anti-aging properties in high temperature and humid environments.

[0050] Selenides can form stable chemical bonds with rubber molecules, thereby improving the intermolecular interactions between rubber and other components, and further improving the mechanical properties, aging resistance and electrical conductivity of rubber products. When used in combination with 2-mercaptobenzimidazole derivatives, the prepared rubber products will have better aging resistance.

[0051] Referring to Example 2 and Example 3 and in combination with Table 2, it can be seen that, relative to Example 2, although the 7-day compressive strength of Example 3 is basically unchanged, the change in compressive strength of Example 3 is significantly reduced, which shows that the addition of attapulgite can effectively improve the durability of the crushed stone grouting material behind the TBM wall.

[0052] The reason may be that the introduction of hydroxyl and sulfide groups requires oxidation treatment of the surface of the rubber particles, and the presence of 2-mercaptobenzimidazole derivatives will limit the occurrence of oxidation. The surface of attapulgite contains a large number of pores, which can load 2-mercaptobenzimidazole derivatives, thereby achieving a sustained release effect, reducing the impact of 2-mercaptobenzimidazole derivatives when modifying the rubber particles, and also serving the purpose of anti-aging when the grouting material is used later.

[0053] Referring to Example 3 and Example 4 and combining with Table 2, it can be seen that compared with Example 3, the 7-day compressive strength of Example 4 is significantly improved, but the change in the compressive strength of Example 4 is basically unchanged, which shows that the introduction of dithiocarbamic acid groups can further improve the toughness of the TBM wall behind the gravel grouting material.

[0054] The reason is that although selenide, like sulfide, can react with double bonds in rubber to form a cross-linked structure and even has better aging resistance and stability, the vulcanization rate of selenide is slower than that of sulfide. The introduction of dithiocarbamic acid groups can exist as an auxiliary accelerator, thereby accelerating the vulcanization process of rubber and improving the mechanical strength and stability of rubber particles.

[0055] Specifically, the dithiocarbamic acid group molecule contains two interacting sulfide bonds. During the vulcanization process, the two sulfide bonds are broken first, and one sulfur atom reacts with the hydrogen atoms in the rubber molecule to form thiol, and the other sulfur atom reacts with the hydrogen atoms in another rubber molecule to form disulfide. Finally, the thiol and disulfide react with hydrogen atoms to form vulcanized rubber.

[0056] With reference to Examples 4 to 6 and in combination with Table 2, it can be seen that, relative to Example 4, the 7-day compressive strength or the change in compressive strength of Examples 5 to 6 is significantly worse, which indicates that when the components of the TBM behind-the-wall crushed stone grouting material are added in the amounts of Example 4, the prepared TBM behind-the-wall crushed stone grouting material will have both better toughness and durability.

[0057] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A high-toughness and high-durability TBM wall behind the crushed stone grouting material, characterized in that: The invention comprises the following raw materials in parts by weight: 800-1000 parts of fine sand, 30-50 parts of bentonite, 100-200 parts of fly ash, 400-600 parts of silicate cement, 70-100 parts of gypsum, 70-100 parts of modified rubber particles, 5-10 parts of early strength agent and 400-600 parts of water; the modified rubber particles are grafted with hydroxyl groups and sulfide groups.

2. The high-toughness and high-durability TBM wall behind-the-wall crushed stone grouting material according to claim 1 is characterized in that: The preparation method of the modified rubber particles is: First, the rubber particles are soaked in a 5% sodium hydroxide solution for 20-30 hours, and then washed with water, and then added into a 5% potassium permanganate solution, and the pH value of the solution is adjusted to 2-3 by sulfuric acid; then, the solution is heated to 50-70°C, and the oxidation reaction is stirred for 1-3 hours. During this period, the pH value is always controlled to be maintained at 2-3 by 5% potassium permanganate solution and sulfuric acid, and then washed with water, and finally the rubber particles are soaked in a sodium bisulfite solution for 1-2 hours, the soaking temperature is 50-70°C, and finally dried to obtain modified rubber particles.

3. The high-toughness and high-durability TBM wall behind-the-wall crushed stone grouting material according to claim 2 is characterized in that: The rubber particles include the following raw materials in parts by weight: 90-110 parts of styrene-butadiene rubber, 4-6 parts of zinc oxide, 1-3 parts of stearic acid, 1-3 parts of sulfur and 1-2 parts of anti-aging accelerator, wherein the anti-aging accelerator is attapulgite loaded with 2-mercaptobenzimidazole derivatives, and the anti-aging accelerator contains selenide and promoting groups.

4. The high-toughness and high-durability TBM wall behind-the-wall crushed stone grouting material according to claim 3 is characterized by: The promoting group is a dithiocarbamate group.

5. The high-toughness and high-durability TBM wall behind-the-wall crushed stone grouting material according to claim 4, characterized in that: The preparation method of the anti-aging accelerator is: Dissolve 3-5g 2-mercaptobenzimidazole-selenide in 20-40ml anhydrous ethanol, then add 18-22ml ethanol-water mixture containing 0.7-0.9g caustic soda, the mass ratio of the two in the ethanol-water mixture is 1:1, stir at room temperature until clear, and then cool the solution to 0°C, then add 5-6ml carbon disulfide-ethanol solution at a rate of 2s / drop, the volume ratio of carbon disulfide to ethanol is 15:100, after the addition is completed, continue to stir for 20-40min, finally add 2-3ml 4-methylpiperidine, then let stand for 5-10min, and then add 50ml iodine-potassium iodide aqueous solution at a rate of 1s / drop, the concentration of iodine is 50.8g / L, the concentration of potassium iodide is 50g / L, after the addition is completed, add 4-8g attapulgite and continue to stir for 1-2h, finally filter, wash, filter and dry to obtain an aging-resistant accelerator.

6. The high-toughness and high-durability TBM wall behind-the-wall crushed stone grouting material according to claim 5, characterized in that: The preparation method of the 2-mercaptobenzimidazole-selenide is as follows: at room temperature, dissolve 2-4g of 2-mercaptobenzimidazole in 150-250ml of anhydrous ethanol, continue stirring until it is clear, and then slowly drop 15-25ml of selenium dioxide-anhydrous ethanol solution, wherein the concentration of the selenium dioxide-anhydrous ethanol solution is 0.05g / ml, the dropping speed is 2s / drop, the reaction temperature is controlled at 40-60°C, and after the drop addition is completed, the stirring is continued for 1-2h, and finally the 2-mercaptobenzimidazole-selenide is filtered, washed, sucked and dried to obtain the 2-mercaptobenzimidazole-selenide.

7. The high-toughness and high-durability TBM wall behind-the-wall crushed stone grouting material according to claim 3, characterized in that: The preparation method of the rubber particles is: The styrene butadiene rubber is plasticized in an internal mixer, and after being evenly mixed, the styrene butadiene rubber is transferred to a double-roll mill for processing. During the processing, zinc oxide, stearic acid, an anti-aging accelerator and sulfur are added one by one, and are fully mixed after each addition. Cutting, rolling, extrusion and degassing are continuously performed during the mixing process. After the mixing is completed, the styrene butadiene rubber compound is left to stand in a dry environment for 20-30 hours, and finally pelletized to obtain rubber particles.

8. A method for preparing the high-toughness and high-durability TBM wall behind-wall crushed stone grouting material according to any one of claims 1 to 7, characterized in that: Its preparation method is: Add fine sand, bentonite, fly ash, silicate cement, gypsum, modified rubber particles, early strength agent and water into the mortar mixer and mix for 2-5 minutes. Then set the grouting pressure to 0.4-0.8MPa, control the flow rate at 50-120L / min, and use four points of shield tail for simultaneous grouting, with the upper and lower ratio of 6.5:3.5 and the injection rate of 125-150%.

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