Sprayed concrete interface reinforced mortar used under water seepage working condition of tunnel in cold region as well as preparation method and application of sprayed concrete interface reinforced mortar

Abstract

The invention relates to sprayed concrete interface reinforced mortar used under a cold region tunnel water seepage working condition, and a preparation method and application thereof, and belongs to the technical field of sprayed concrete. The raw materials comprise cement, water, calcium salt, a phase change temperature control component, a modified silane coupling agent, fine aggregate, a liquid alkali-free accelerator and a water reducing agent, the phase change temperature control component is a mixture of emulsion polymer powder and an adhesive, and the modified silane coupling agent is a nano material modified silane coupling agent. The method is specially used for effectively improving the bonding strength and the water penetration resistance of the sprayed concrete in the low-temperature environment when a tunnel in a cold region faces the low-temperature water seepage construction environment. The new thought not only focuses on solving the common key problems that the concrete bonding force is reduced and the concrete is easily damaged by freezing and thawing in the tunnel construction in the cold region, but also aims at fundamentally improving the bonding condition between the concrete and the construction surface through a refined surface treatment technology; and the capability of resisting structural damage caused by low temperature and moisture permeation is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of shotcrete, and in particular to a shotcrete interface reinforcement mortar for use in tunnel water seepage conditions in cold regions, and a preparation method and application thereof. Background Art

[0002] As an efficient concrete construction technology, shotcrete can quickly and evenly cover the surface to be reinforced or repaired with concrete. It is particularly suitable for the initial support of tunnels and the stabilization and repair of slopes. The application of this technology not only greatly improves the project construction efficiency, effectively reduces labor and material costs, but also ensures that the project quality and safety standards are met. Therefore, shotcrete plays a vital role in building and infrastructure construction. In high-altitude areas, tunnel construction in winter often faces extreme temperature fluctuations, accompanied by severe water seepage conditions, and even causes rock surface icing, which is extremely unfavorable for construction. Low temperature and water seepage not only hinder the early strength development of shotcrete, making it difficult to meet the requirements of rapid construction and strength, but also cause water freezing and the hydration reaction inside the concrete to be blocked, resulting in unstable initial support. Therefore, for tunnels in cold areas facing low-temperature water seepage construction environments, how to effectively improve the bonding strength and anti-freezing properties of shotcrete can help ensure construction quality and safety, and can also provide strong guarantees for the long-term stability and service life of the tunnel.

[0003] In order to reduce the rebound rate of tunnel shotcrete under water seepage conditions in cold-region tunnels, in-depth and systematic research on the existing technologies has been conducted. These studies not only focus on the optimization of concrete mix ratios, but also cover multiple aspects such as construction control, equipment maintenance, and the application of new materials. For example, a Chinese patent application with publication number CN114853419 A discloses a low-rebound shotcrete for high-altitude railway tunnels and a preparation method thereof. The rebound rate of shotcrete is greatly reduced by modifying mineral admixtures and modified fibers, so that the rebound rate of shotcrete is less than 12%, reducing a large amount of resource waste and achieving green and low-carbon construction. However, the fiber materials and admixtures used are prone to cause problems such as high viscosity of the concrete mixture and poor collapse resistance, which is not conducive to actual spraying.

[0004] The Chinese patent application with publication number CN115611585 A discloses a C25 anti-corrosion shotcrete for water-rich surrounding rock in tunnels and a method for preparing and using the shotcrete. When the method is used for water-rich surrounding rock, it can effectively prevent the shotcrete from having cavities and falling blocks, thereby improving the construction quality and promoting engineering safety; it can also reduce the amount of shotcrete rebound, achieve energy saving and consumption reduction, and promote engineering environmental protection. However, the practicality of relying solely on the toughening and strengthening effects of components such as silica fume and polypropylene fiber on low-temperature and humid rock surfaces remains to be studied.

[0005] The Chinese patent application with the publication number CN118724540 A discloses a low-shrinkage and high-freeze-resistant shotcrete, its preparation method and application. Specifically, it discloses a low-shrinkage and high-freeze-resistant shotcrete prepared from solid waste materials, which can effectively promote the resource utilization and high-value utilization of solid waste, significantly reduce the volume shrinkage phenomenon of shotcrete during the curing process, and greatly enhance its ability to resist low-temperature freeze-thaw cycle damage. However, although this solution significantly enhances the low-temperature freeze-resistant performance, it does not consider the construction rebound rate under the condition of low-temperature water seepage.

[0006] The Chinese patent with the publication number CN118754581 A discloses a coagulation-fast and erosion-resistant shotcrete for water-rich tunnels, its preparation method and application. Specifically, it discloses a shotcrete for water-rich tunnels with fast coagulation and erosion resistance prepared by adding modified microsilica powder, thickening admixture, and asphalt-based carbon fiber, which can achieve good prevention and control effects on different types of tunnel water inrush in water-rich tunnels. However, this method will inevitably increase the viscosity of the shotcrete and the construction difficulty, and at the same time, it also needs to be used with a faster-setting accelerator with better coagulation-promoting effect.

[0007] The Chinese patent with the announcement number CN108756939 B discloses a heating system and method for the sprayed concrete and accelerator used in shotcrete construction. The compressed air and / or accelerator heated by the heating device are mixed with the materials of the concrete spraying machine and then sprayed out through the nozzle to complete the construction. By heating the sprayed concrete and the accelerator, the amount of accelerator used can be effectively reduced, the final setting time can be shortened, the rebound effect can be reduced, and the work efficiency can be improved. However, this method involves the transformation of the wet spraying machine, and the heat preservation effect of the air pressure / concrete temperature rise time is worthy of exploration.

[0008] Therefore, there is an urgent need to develop a shotcrete construction method suitable for the water seepage condition in cold-region tunnels. On the one hand, it can ensure the construction performance of the shotcrete, and on the other hand, it can also solve the problems of poor concrete coagulation effect and increased concrete rebound rate under low-temperature conditions. This can guarantee the construction quality and safety, and provide a strong guarantee for the long-term stability and service life of the tunnel. Summary of the Invention

[0009] Technical problems to be solved: Aiming at the problems of poor adhesion and high rebound rate of shotcrete in the water seepage condition in cold regions in the prior art, the present invention provides an interface-enhancing mortar for shotcrete in the water seepage condition in cold-region tunnels, its preparation method and application. Specifically for the construction environment of cold-region tunnels facing low-temperature water seepage, it can effectively improve the adhesion strength of the shotcrete and reduce the rebound rate of the shotcrete.

[0010] Technical solution: The first object of the present invention is to provide a shotcrete interface enhancing mortar for seepage conditions in cold region tunnels. The raw materials are proportioned by mass as follows: 480 - 520 parts of cement, 160 - 180 parts of water, 20 - 40 parts of calcium salt, 2 - 10 parts of phase change temperature control component, 4 - 8 parts of modified silane coupling agent, 800 - 900 parts of fine aggregate, 30 - 45 parts of liquid alkali-free accelerating agent, and 4 - 6 parts of water reducing agent. The calcium salt is at least one of calcium sulfate, calcium formate, and calcium acrylate. The phase change temperature control component is a mixture of emulsion polymer powder and adhesive, and the mass ratio of the emulsion polymer powder to the adhesive is 0.8 - 1.2:1.6 - 2.4. The modified silane coupling agent is a nanomaterial-modified silane coupling agent, and the nanomaterial is at least one of nano-silica, nano-aluminum oxide, nano-calcium carbonate, and nano-titanium oxide. The silane coupling agent is tetraethoxysilane, γ-aminopropyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, or tridecafluorooctyltrimethoxysilane.

[0011] In the present invention, the calcium salt is at least one of calcium sulfate, calcium formate, and calcium acrylate. Preferably, the calcium salt is selected as calcium acrylate. The polar groups of -COOCa and -OH in calcium acrylate can react with Ca 2+ and Al 3+ in the cement. When it is added to the interface enhancing mortar, it will aggregate on the rock surface and further form a network system, overlapping with another network system formed by the concrete, enhancing the bonding force between the tunnel construction surface and the concrete.

[0012] Preferably, the cement is ordinary Portland cement with a strength grade ≥ 42.5.

[0013] Preferably, the fine aggregate is manufactured sand, river sand, or mixed sand.

[0014] Preferably, the fineness modulus of the fine aggregate is 2.7 - 3.2, the mud content < 0.5%, the water absorption < 0.5%, the apparent density is 2600 - 2650 kg / m 3 , and the bulk density is 1500 - 1550 kg / m 3 .

[0015] Preferably, the liquid alkali-free accelerating agent is a high-activity aluminum-phase fluoride-free and alkali-free accelerating agent, and the water reducing agent is a polycarboxylate superplasticizer.

[0016] Furthermore, the water reducing efficiency of the polycarboxylate superplasticizer > 20%, and the solid content is 15 - 20%.

[0017] Preferably, the initial setting time of the high-activity aluminum-phase fluoride-free and alkali-free accelerating agent is < 3 min, the final setting time is < 10 min, and the 1-day mortar compressive strength of the accelerating agent is > 10 MPa, which is much higher than the performance requirements of the enterprise standard GB / T 35159-2017 for accelerating agents.

[0018] Preferably, the emulsion polymer powder is polyvinyl acetate powder, vinyl acetate-ethylene powder or styrene-butadiene emulsion polymer powder, and the adhesive is acrylate adhesive, polyurethane adhesive or silicone adhesive.

[0019] Furthermore, the emulsion polymer powder is vinyl acetate-ethylene powder and the adhesive is acrylate adhesive. The phase change temperature control component can form a high-binding-strength silica gel cluster layer in the interface-enhanced mortar. When the external low temperature approaches the phase change point of the phase change material (< 10 °C), the phase change material will solidify and release a large amount of heat, which can play a role in delaying temperature changes.

[0020] Preferably, the preparation method of the nanomaterial-modified silane coupling agent is as follows: Add nanomaterials and deionized water with a mass ratio of 0.5 - 1.5:15 - 25 into a reaction vessel, carry out hydrothermal treatment at 70 - 90 °C with constant stirring at 1000 r / min for 4 - 7 h, then add the hydrothermally treated nanomaterials and silane coupling agent into the reaction vessel according to a mass ratio of 1.2 - 1.4:0.8 - 1.2, and stir at a constant temperature of 500 r / min at 20 - 30 °C for 20 - 24 h to obtain the nanomaterial-modified silane coupling agent.

[0021] Furthermore, nano calcium carbonate is selected as the nanomaterial. Tridecafluorooctyltrimethoxysilane is selected as the silane coupling agent. Methanol produced by the hydrolysis of the silane coupling agent is not conducive to the hydration of cement particles. The silane coupling agent modified by nano calcium carbonate will generate silanol groups when hydrolyzed in an alkaline environment, and the silanol groups will further undergo dehydration condensation reactions with alkaline substances in the concrete to form stable silicon-oxygen bonds, improving the interfacial adhesion. At the same time, the strong hydrophobic effect in tridecafluorooctyltrimethoxysilane can hinder the water erosion of the tunnel seepage rock wall on the hardening of mortar / concrete.

[0022] The second object of the present invention is to provide a preparation method of the above-mentioned shotcrete interface-enhanced mortar for cold region tunnel seepage conditions, and the steps are as follows: Add cement, calcium salt, fine aggregate, water and water reducer into a mixer and stir evenly, then add the phase change temperature control component and the modified silane coupling agent into the mixer and continue to stir until evenly mixed, then load the mixed mortar into a concrete spraying machine, and add a liquid alkali-free accelerating agent at the nozzle, and then carry out spraying construction.

[0023] The third object of the present invention is to provide the application of the above-mentioned shotcrete interface enhancement mortar for water seepage conditions in cold-region tunnels as a construction material for interface enhancement mortar in cold-region tunnel water seepage conditions. During construction, the shotcrete interface enhancement mortar for water seepage conditions in cold-region tunnels except for liquid alkali-free accelerating agent is loaded into a concrete spraying machine, and the liquid alkali-free accelerating agent is added at the nozzle, and it is sprayed to a thickness of 1-2 cm on the construction surface of the cold-region tunnel, thus completing the construction of the interface enhancement mortar.

[0024] Beneficial effects: (1) The polar groups (-COOCa and -OH) in the calcium salts of the present invention, especially calcium acrylate, can react with the ions (Ca 2+ 、Al 3+ ) in cement, thereby forming a network system on the rock surface and overlapping with the network system of concrete. This interaction significantly enhances the bonding force between the tunnel construction surface and concrete, improving the overall structural stability and durability. The silane coupling agent modified by nanomaterials hydrolyzes in an alkaline environment to generate silanol groups, which undergo dehydration condensation reactions with the alkaline substances in concrete to form stable silicon-oxygen bonds, thus enhancing the interfacial bonding force. At the same time, the strong hydrophobic component in the modified silane coupling agent can effectively hinder the water erosion effect of the water seepage rock wall of the tunnel on the hardening of the mortar / concrete, protecting the structure from moisture damage. The phase change temperature control component in the interface enhancement mortar can solidify and release a large amount of heat when the temperature is close to the phase change point at low temperature, thereby playing a role in delaying temperature changes. This temperature stabilization effect helps to reduce the negative impact of temperature changes on the mortar / concrete structure, improving the structural stability and durability, especially being of great significance under extreme climate conditions.

[0025] (2) The technical solution of the present invention integrates advanced material modification, surface pretreatment technology, and environmental adaptability design, aiming to ensure that even under extremely harsh climate conditions in cold-region tunnels, the shotcrete can exhibit excellent bonding stability and outstanding frost resistance durability. This innovation not only provides solid technical support for the safe construction and long-term stable operation of tunnel projects, but also opens up new paths for the construction of other key infrastructure such as bridges, water conservancy hubs, and underground comprehensive pipe corridors in cold regions, showing an extremely broad and potential application prospect. With the further research and development and popularization application of this technology, it is expected to play an inestimable positive role in improving the construction quality of facilities in cold regions, accelerating the construction progress, and reducing the maintenance cost. Detailed implementation manners

[0026] The present invention will be further described below in conjunction with specific embodiments.

[0027] To more comprehensively elaborate the core concepts and application effects of the present invention, we will describe it in detail in conjunction with specific embodiments. In this embodiment, the raw materials are all commercially available, and the manufacturers and related models are as follows:

[0028] The cement was purchased from Southwest Cement Co., Ltd., with the model of P·O 42.5 cement. The water reducer and liquid alkali-free accelerator were both from Jiangsu Sobute New Materials Co., Ltd., with the models of PCA®-Ⅰ series polycarboxylate superplasticizer and SBT-N(Ⅱ) liquid accelerator respectively. The fine aggregate was river sand, with a fineness modulus of 2.9, a mud content of <0.5%, a water absorption rate of <0.5%, and an apparent density of 2630 kg / m 3 , and a bulk density of 1525 kg / m 3 . The coarse aggregate was single-sized crushed stone of 5-10mm.

[0029] The calcium acrylate was purchased from Hubei Xinghengye Technology Co., Ltd.; the vinyl acetate-ethylene powder was purchased from Wuhan Jixin Yibang Biotechnology Co., Ltd.; the acrylate adhesive was purchased from Dongguan Guangzhan Adhesive Industry Co., Ltd.; the trifluorooctyltrimethoxysilane was purchased from Hangzhou Jessica Chemical Co., Ltd.; the nano calcium carbonate was purchased from Hubei Huifu Nano Materials Co., Ltd.

[0030] The preparation method of the interface-enhanced mortar in Examples 1-7 and Comparative Examples 1-5 is as follows:

[0031] 1. Prepare the modified silane coupling agent. Add nano calcium carbonate and deionized water with a mass ratio of 1:12 into a flask, carry out hydrothermal reaction at 85°C with constant stirring at 1000 r / min for 6 h, and then add the hydrothermally treated nano calcium carbonate and the silane coupling agent trifluorooctyltrimethoxysilane into the flask according to a mass ratio of 1.2:1, and stir at a constant temperature of 500 r / min at 25°C for 22 h to obtain the nano material modified silane coupling agent.

[0032] 2. Prepare the phase change temperature control component. Mix the vinyl acetate-ethylene powder and the acrylate adhesive evenly according to a mass ratio of 1:2 to complete the preparation process.

[0033] 3. Add the weighed cement, calcium salt (calcium acrylate), fine aggregate, water, and water reducer into a mixer and stir at a stirring speed of 20 r / min for 90 s until uniform, and then add the phase change temperature control component and the modified silane coupling agent and continue to stir for 30 s until uniform.

[0034] 4. Load the prepared interface-enhanced mortar into a concrete spraying machine, add the accelerator at the nozzle, and spray 1-2 cm onto the tunnel construction surface to complete the construction of the interface-enhanced mortar.

[0035] The preparation method of the shotcrete for the tunnel construction surface is as follows: Add the same batch of raw materials as the interfacial enhancement mortar in the examples: cement, fine aggregate, coarse aggregate, water, and water reducer into a mixer and stir evenly, then load it into a wet concrete shotcreting machine, add a quick-setting agent at the nozzle, and spray it to the designed thickness (15 cm) of the tunnel construction surface. It will harden completely within 30 minutes, and thus the shotcrete construction is completed to obtain the tunnel construction surface in cold regions.

[0036] The following Table 1 and Table 2 show the raw material components and ratio parameters of the interfacial enhancement mortar and shotcrete provided in the examples and comparative examples.

[0037] Table 1 Raw material components of the interfacial enhancement mortar in the comparative examples and examples (kg / m 3 )

[0038]

[0039] Table 2 Raw material components of the shotcrete (tunnel construction surface) in the comparative examples and examples (kg / m 3 )

[0040]

[0041] The preparation methods of Examples 1 to 7 and Comparative Examples 1 to 4 are the same. The difference lies in the changes in the components of the interfacial enhancement mortar, while the shotcrete used has the same mix ratio.

[0042] Example 1

[0043] In this example, the interfacial enhancement mortar does not contain phase change temperature control components and modified silane coupling agents.

[0044] Example 2

[0045] In this example, the interfacial enhancement mortar does not contain calcium acrylate and modified silane coupling agents.

[0046] Example 3

[0047] In this example, the interfacial enhancement mortar does not contain calcium acrylate and phase change temperature control components.

[0048] Example 4

[0049] In this example, the interfacial enhancement mortar does not contain modified silane coupling agents.

[0050] Example 5

[0051] In this example, the interfacial enhancement mortar does not contain calcium acrylate.

[0052] Example 6

[0053] In this example, the interfacial enhancement mortar does not contain phase change temperature control components.

[0054] Example 7

[0055] This example is for the components of a complete interface-enhanced mortar.

[0056] Example 8

[0057] Same as Example 7, except that in this example, there are 480 parts of cement, 160 parts of water, 20 parts of calcium salt, 2 parts of phase change temperature control component, 4 parts of modified silane coupling agent, 800 parts of fine aggregate, 30 parts of liquid alkali-free quick-setting agent, and 4 parts of water reducer.

[0058] Example 9

[0059] Same as Example 7, except that in this example, there are 520 parts of cement, 180 parts of water, 40 parts of calcium salt, 10 parts of phase change temperature control component, 8 parts of modified silane coupling agent, 900 parts of fine aggregate, 45 parts of liquid alkali-free quick-setting agent, and 6 parts of water reducer.

[0060] Comparative Example 1

[0061] This comparative example does not contain interface-enhanced mortar.

[0062] Comparative Example 2

[0063] The difference between this comparative example and Example 1 is that in this comparative example, the calcium salt is calcium formate, while in Example 1, it is calcium acrylate.

[0064] Comparative Example 3

[0065] The difference between this comparative example and Example 2 is the phase change temperature control component. The proportion (mass ratio) of the phase change temperature control component in Comparative Example 3 is: polypropylene acetate powder: silicone adhesive = 1:2. While the proportion (mass ratio) of the phase change temperature control component in Example 2 is: vinyl acetate-ethylene powder: acrylate adhesive = 1:2.

[0066] Comparative Example 4

[0067] The difference between this comparative example and Example 3 is the silane coupling agent used in the modified silane coupling agent. In this comparative example, tetraethoxysilane is used as the silane coupling agent, while in Example 3, it is tridecafluorooctyltrimethylsilane.

[0068] Comparative Example 5

[0069] The difference between this comparative example and Example 7 is the dosage (mass) of calcium salt, phase change temperature control component, and modified silane coupling agent. In this comparative example, calcium salt: phase change temperature control component: modified silane coupling agent = 20:3:4, while in Example 7, calcium salt: phase change temperature control component: modified silane coupling agent = 25:5:6.

[0070] Performance test:

[0071] To verify the low-temperature construction performance achieved by the shotcrete interface enhancement mortar for water seepage conditions in cold-region tunnels, its preparation method and application provided in the above embodiments and comparative examples of the present invention, a bond strength test of core-drilled shotcrete was carried out with reference to Appendix M in the Standard for Technical Code of Rock and Soil Anchor and Shotcrete Support Engineering GB / T 50086-2015; the water permeability resistance of shotcrete was tested by the water seepage height method with reference to the Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete GB / T 50082-2009; the real-time temperature of the shotcrete interface enhancement mortar on the tunnel construction surface was measured after 10 minutes using a Raytek ST60+ infrared thermometer; the actual rebound rate of shotcrete was tested with reference to Appendix G in the Technical Specification for Application of Shotcrete JGJ / T 372-2016.

[0072] Table 3 shows the performance test results of the tunnel interface enhancement mortar composite shotcrete for Examples 1 to 7 and Comparative Examples 1 to 5.

[0073] Table 3 Performance Test of Tunnel Interface Enhancement Mortar Composite Shotcrete

[0074]

[0075] Combining Examples 1, 3, 6, Comparative Example 1 and Comparative Example 2, it can be seen that using calcium acrylate has a higher bond strength than calcium formate, and the combined action of calcium acrylate and the modified silane coupling agent can enhance the bond strength between the shotcrete and the tunnel rock formation.

[0076] Combining Examples 2, 4, 5, Comparative Example 1 and Comparative Example 3, it can be seen that adding the phase change temperature control component can increase the temperature of the construction surface by about 10°C. And the combination of vinyl acetate-ethylene powder and acrylate adhesive has more excellent temperature rise performance.

[0077] Combining Examples 3, 5, 6, Comparative Example 1 and Comparative Example 4, it can be seen that the interfacial hydrophobic effect of the modified silane coupling agent can enhance the water penetration resistance of the shotcrete, and using tridecafluorooctyltrimethylsilane has stronger hydrophobicity than tetraethoxysilane.

[0078] Combining Examples 4 to 7 and Comparative Examples 1 and 5, it can be seen that the use of the interface enhancement mortar can increase the temperature of the construction surface, enhance the bond strength and water penetration resistance, and reduce the rebound rate of the shotcrete. Reducing the dosages of calcium salt, phase change temperature control component and modified silane coupling agent will weaken this performance.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A shotcrete interface reinforcement mortar for use in tunnel water seepage conditions in cold regions, characterized in that: The raw materials are proportioned as follows by mass: 480-520 parts of cement, 160-180 parts of water, 20-40 parts of calcium salt, 2-10 parts of phase-change temperature control component, 4-8 parts of modified silane coupling agent, 800-900 parts of fine aggregate, 30-45 parts of liquid alkali-free quick-setting agent and 4-6 parts of water reducer, wherein the calcium salt is at least one of calcium sulfate, calcium formate and calcium acrylate, the phase-change temperature control component is a mixture of emulsion polymer powder and adhesive, the mass ratio of the emulsion polymer powder to the adhesive is 0.8-1.2:1.6-2.4, the modified silane coupling agent is a nano material modified silane coupling agent, the nano material is at least one of nano silicon dioxide, nano aluminum oxide, nano calcium carbonate and nano titanium oxide, and the silane coupling agent is tetraethoxysilane, γ-aminopropyltriethoxysilane, 3-isocyanatepropyltriethoxysilane or tridecafluorooctyltrimethoxysilane.

2. The shotcrete interface reinforcement mortar for use in tunnel water seepage conditions in cold regions according to claim 1, characterized in that: The cement is ordinary Portland cement with a strength grade of ≥42.

5.

3. The shotcrete interface reinforcement mortar for use in tunnel water seepage conditions in cold regions according to claim 1, characterized in that: The fine aggregate is machine-made sand, river sand or mixed sand.

4. The shotcrete interface reinforcement mortar for use in tunnel water seepage conditions in cold regions according to claim 3, characterized in that: Fine aggregate fineness modulus 2.7~3.2, mud content <0.5%, water absorption <0.5%, apparent density 2600-2650kg / m 3 , bulk density is 1500-1550 kg / m 3 .

5. The shotcrete interface reinforcement mortar for use in tunnel water seepage conditions in cold regions according to claim 1, characterized in that: The liquid alkali-free quick-setting agent is a high-activity aluminum phase fluorine-free alkali-free quick-setting agent, and the water reducer is a polycarboxylic acid high-efficiency water reducer.

6. The shotcrete interface reinforcement mortar for use in tunnel water seepage conditions in cold regions according to claim 5, characterized in that: The high-activity aluminum phase fluorine-free and alkali-free quick-setting agent has an initial setting time of <3 min, a final setting time of <10 min, and a 1d mortar compressive strength of >10 MPa.

7. The shotcrete interface reinforcement mortar for use in tunnel water seepage conditions in cold regions according to claim 1, characterized in that: The emulsion polymer powder is polyvinyl acetate powder, vinyl acetate-ethylene powder or styrene-butadiene emulsion polymer powder, and the adhesive is acrylic adhesive, polyurethane adhesive or organic silicone adhesive.

8. The shotcrete interface reinforcement mortar for use in tunnel water seepage conditions in cold regions according to claim 1, characterized in that: The preparation method of the nanomaterial modified silane coupling agent is as follows: adding nanomaterial and deionized water in a mass ratio of 0.5-1.5:15-25 into a reaction container, stirring at a constant temperature of 1000 r / min for 4-7 hours at 70-90° C. for hydrothermal treatment, then adding the hydrothermally treated nanomaterial and silane coupling agent in a mass ratio of 1.2-1.4:0.8-1.2 into the reaction container, stirring at a constant temperature of 500 r / min for 20-24 hours at 20-30° C., to obtain the nanomaterial modified silane coupling agent.

9. The method for preparing the shotcrete interface reinforcement mortar for use in cold region tunnel water seepage conditions according to any one of claims 1 to 8, characterized in that: The steps are as follows: add cement, calcium salt, fine aggregate, water and water reducing agent into the mixer and mix evenly, then add the phase change temperature control component and modified silane coupling agent into the mixer and continue to mix until evenly mixed, then load the mixed mortar into the concrete spraying machine, add liquid alkali-free quick-setting agent at the nozzle, and start spraying construction.

10. Use of the shotcrete interface reinforcement mortar for cold region tunnel water seepage conditions according to any one of claims 1 to 8 as a construction material for interface reinforcement mortar for cold region tunnel water seepage conditions, characterized in that: During construction, the shotcrete interface reinforcement mortar for water seepage in cold-region tunnels except for the liquid alkali-free quick-setting agent is loaded into the concrete spraying machine, and the liquid alkali-free quick-setting agent is added at the nozzle, and sprayed 1~2 cm to the construction surface of the cold-region tunnel to complete the interface reinforcement mortar construction.

Images