A kind of anti-seepage early-strength shotcrete and its application in over-excavation seepage conditions

Abstract

The present invention discloses an anti-seepage early-strength shotcrete and its application under over-excavation and water seepage conditions, belonging to the technical field of tunnel lining concrete. The anti-seepage early-strength shotcrete includes the following components: early-strength cementitious material, fine aggregate, coarse aggregate, waterproof and dense component, water reducer, liquid alkali-free quick-setting agent, and water; the waterproof and dense component is composed of a waterproofing agent, an inorganic layered carrier, a spray layer interface enhancer, and water; the inorganic layered carrier is an inorganic silicate layered mineral; the spray layer interface enhancer is a mixture of a copolymer emulsion, a viscosity-increasing component, and nanoparticles. The present invention forms an anti-seepage early-strength shotcrete for over-excavation of surrounding rocks through the early-strength optimization design of cementitious materials and the incorporation of waterproof and dense components. It can significantly improve the situation of shotcrete block dropout under over-excavation conditions and further achieve early support for weak surrounding rocks.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel lining concrete, and in particular relates to an anti-seepage early-strength shotcrete and its application in over-excavation seepage working conditions. Background Art

[0002] The New Austrian Tunnel Construction Method (NATM) defines the first-layer initial support structure based on shotcrete, the quality of which is directly related to the construction and service safety of the tunnel structure. However, due to its special spraying process and mortar material composition, the hardened shotcrete has more pores and low early support strength. Therefore, the material's anti-seepage and waterproof properties and bonding effect with the surrounding rock are poor. During the construction process, it is easy to cause shotcrete to fall off, hardened flatness to be poor, and rebound loss to be large. [Zeng Luping, Zhao Shuang, Wang Wei, Qiao Min, Mu Song, Ran Qianping, Hong Jinxiang, Hu Min. Bubble structure characteristics, water penetration resistance and frost resistance of hardened shotcrete [J]. Journal of the Chinese Ceramic Society, 2020, 48(11): 1781-1790]. Taking the mountainous areas of southwest my country as an example, the mountainous terrain is complex, the soft surrounding rock is relatively abundant, and there is a developed water system. Therefore, the initial support construction of tunnels in this area often encounters complex working conditions such as rich water and over-excavation. However, when overcut occurs in water-rich tunnels, shotcrete is susceptible to the combined effects of gravity and rapid hydration during the spraying process. Consequently, existing technologies for overcuts exceeding 30cm are prone to shotcrete shedding, resulting in significant losses in rebound material costs. Therefore, improving shotcrete's impermeability and early support strength are crucial for enhancing its construction and service performance under overcut and water seepage conditions.

[0003] Existing research focuses on improving the performance of shotcrete materials and construction methods for overexcavation and water seepage. While much research has focused on improving drainage processes and enhancing the anti-seepage properties of shotcrete materials, relatively little research has focused on developing shotcrete materials and supporting construction methods for conditions involving both overexcavation and water seepage. Furthermore, there has been little research focused on improving the early strength of shotcrete and improving the shotcrete process for overexcavation in soft rock. Patent No. CN108894801B, "Anti-seepage support structure and construction method for high-pressure, water-rich cavity sections in tunnels," discloses a support and anti-seepage structure that sequentially utilizes a double-layer initial support, a waterproof structure, and a double-layer secondary lining. The initial support utilizes a circular ring structure composed of a full-ring steel arch frame shotcrete. The waterproof structure utilizes waterstops at construction joints and expansion joints to provide water seepage reinforcement. However, the use of this anti-seepage support structure is complex and the material cost is relatively high. The water seepage reinforcement effect of the waterproof structure and waterstop is not suitable for tunnel conditions with significant water seepage, and can easily increase the pressure of water seepage outside the lining later. Patent No. CN114738050A "An Anti-seepage and Drainage Construction Method for Complex Soft Rock Tunnels" discloses a waterproofing and drainage construction method for complex soft rock tunnels. The construction method adopts measures such as advance drilling, well point pipe pumping, advance pre-grouting of the heading face, and drainage structure construction to achieve waterproofing and drainage of groundwater and surrounding rock seepage. However, the construction method does not take into account the inherent anti-seepage properties of the shotcrete material. In addition, the various advance construction measures included in the construction method require a lot of manpower, material resources and time, and have low economic efficiency, and are not suitable for large-scale promotion. Patent No. CN107916945A "Waterproof sprayed layer structure using anti-seepage sprayed concrete and its construction method" discloses an anti-seepage sprayed concrete and a waterproof sprayed layer structure. The waterproof sprayed layer structure consists of a temporary drainage system and anti-seepage sprayed concrete. The temporary drainage system sets horizontal and vertical drainage blind pipes, permeable cloth and other anti-drainage materials on the surrounding rock surface to form a waterproof drainage network. The sprayed concrete uses silica fume, mineral powder and cellulose fiber to improve the anti-seepage performance of the concrete material. However, the waterproof drainage network is only suitable for the situation where the surrounding rock surface has less seepage, such as the enrichment of point seepage. In addition, the anti-seepage sprayed concrete uses a high proportion of mineral admixtures such as silica fume and mineral powder, and is mixed with a certain amount of fiber material, which easily causes the viscosity of the concrete mixture to be higher, which is not conducive to actual spraying. Patent No. CN113321474A "A kind of anti-seepage shotcrete" discloses an anti-seepage shotcrete, which is prepared by anti-seepage fiber, composite admixture, and slow-release expansion material, wherein the slow-release expansion material is formed by physically coating other materials with a coating material. However, the spraying performance and anti-seepage performance of the shotcrete when over-excavation and water seepage conditions coexist are still unknown, and it does not involve the improvement of the early strength of concrete.Patent No. JP3549632B2, "Sement Rapid-Setting Material and Semint Composition," discloses a cement composition with a cement accelerator and rapid-setting properties. This composition offers excellent water-stopping and anti-seepage properties for jetting during tunnel seepage. The cement composition contains amorphous calcium aluminate silicate, amorphous calcium aluminate borate, and amorphous calcium aluminate phosphate, with an amorphous content exceeding 50%. However, the amorphous component and its content are difficult to obtain and control, and the rapid-setting component in the composition is highly alkaline, which can easily cause a decrease in the later strength of the primary concrete. Patent No. KR100870673B1. Disclosed are a dextrin-modified admixture composition and its application in shotcrete. The dextrin-modified composition is prepared by mixing maltodextrin with other admixtures. When used in shotcrete, the composition can reduce spray rebound and water seepage. However, the maltodextrin is a polysaccharide molecule and its addition to shotcrete can easily bring about a certain retarding effect. Furthermore, the composition can only improve the working condition of water seepage on the surrounding rock surface, and its effect on shotcrete construction under conditions of large water seepage and over-excavation is unknown.

[0004] Therefore, it is urgent to develop a shotcrete material with good anti-seepage performance and fast early strength development, and to develop a tunnel shotcrete construction method suitable for over-excavation and water seepage conditions to ensure the construction quality and service performance of the tunnel support structure. Summary of the Invention

[0005] In order to solve the technical problems of the above-mentioned existing technologies, such as low early strength of shotcrete, poor impermeability, weak bonding effect with surrounding rock, and difficulty in ensuring the construction quality and service performance of shotcrete under over-excavation and water seepage conditions, the present invention provides a kind of impermeable early-strength shotcrete, and provides its application in over-excavation and water seepage conditions, aiming to improve the shotcrete construction quality and impermeability of tunnel shotcrete in water-rich and complex soft surrounding rock environment.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The invention discloses an anti-seepage early-strength shotcrete, whose raw materials include the following components: early-strength cementitious material, fine aggregate, coarse aggregate, waterproof and dense component, water reducer, liquid alkali-free accelerator, and water; per cubic meter, the early-strength cementitious material comprises 400kg-500kg; fine aggregate comprises 850kg-950kg; coarse aggregate comprises 850kg-950kg; liquid alkali-free accelerator comprises 30kg-45kg; the waterproof and dense component accounts for 5%-10% of the mass of the early-strength cementitious material; the water reducer accounts for 0.5%-1.5% of the mass of the early-strength cementitious material; and the water-cement ratio is 0.32-0.38.

[0008] The waterproof and dense component consists of a waterproofing agent, an inorganic layered carrier, a spray layer interface enhancer and water; the mass ratio of the waterproofing agent, the inorganic layered carrier, the spray layer interface enhancer and water is 20-30:1-5:5-10:55-75; furthermore, the solid content of the waterproof and dense component is 25%-35%.

[0009] The inorganic layered carrier is an inorganic silicate layered mineral. Furthermore, the inorganic layered carrier is selected from one of sepiolite, attapulgite, lithium magnesium silicate, kaolin, or bentonite. The waterproofing agent is selected from one of a siloxane waterproofing agent, a fatty acid waterproofing agent, or a cement-based penetrating crystalline waterproofing agent. Further preferably, the waterproofing agent is a cement-based penetrating crystalline waterproofing agent. Compared to siloxane and fatty acid waterproofing agents, the cement-based penetrating crystalline waterproofing agent preferably exhibits superior particle stacking and packing density when used with the inorganic layered carrier, has minimal negative impact on the later strength of the shotcrete, and exhibits a synergistic waterproofing and dense packing compatibility-enhancing effect.

[0010] The spraying interface enhancer is a mixture of copolymer emulsion, viscosity-increasing component and nanoparticles, wherein the mass ratio of copolymer emulsion, viscosity-increasing component and nanoparticles is 40-80:0.1-1.0:20-40; the solid content of the spraying interface enhancer is 20%-40%.

[0011] The copolymer emulsion is an aqueous emulsion with a viscosity of more than 1000 MPa.s; further, the copolymer emulsion is selected from one of vinyl propionate polymer emulsion, pure acrylic acid copolymer emulsion, styrene-acrylate copolymer emulsion, vinyl acetate-vinyl versatate copolymer emulsion, vinyl acetate-ethylene copolymer emulsion or vinyl acetate-vinyl chloride-acrylate copolymer emulsion; the viscosity-increasing component is selected from one of hydroxypropyl methylcellulose ether, hydroxyethyl methylcellulose ether, gellan gum, xanthan gum, diutan gum, weinlun gum, polyacrylamide, polyvinyl alcohol or polyethylene glycol; the nanoparticles are one of nano-silicon dioxide, nano-alumina, nano-calcium carbonate, nano-zeolite, nano-magnesium oxide, nano-titanium dioxide or nano-zinc oxide; and the particle size of the nanoparticles is 20-500 nm.

[0012] The early-strength cementing material is a mixture of silicate cement, rapid-hardening cement, calcium oxide and gypsum, wherein the mass ratio of silicate cement, rapid-hardening cement, calcium oxide and gypsum is 8-12:3-6:1-3:1-3; the strength grade of silicate cement is not less than 42.5, and the proportion of mineral admixture is not more than 5%; the rapid-hardening cement is selected from one of aluminate cement, sulfoaluminate cement or phosphate cement, among which phosphate cement is preferred; the gypsum is selected from one of dihydrate gypsum, hemihydrate gypsum, anhydrous gypsum, phosphogypsum or desulfurized gypsum, among which hemihydrate gypsum is preferred.

[0013] The coarse aggregate is 5-10 mm single-particle crushed stone; further, the needle-like content in the crushed stone is less than 10%, the mud content is less than 0.5%, the water absorption rate is less than 0.5%, and the loose stacking void ratio is less than 40%; the fine aggregate is selected from one of machine-made sand, river sand or mixed sand; further, the fineness modulus of the fine aggregate is 2.5-3.0, the cumulative sieve residue of 4.75 mm is less than 5%, and the mud content is less than 0.5%.

[0014] The water reducer is a mixture of a polycarboxylate water reducer and a retarder, wherein the retarder accounts for 10%-20% of the mass proportion of the polycarboxylate water reducer; the retarder is selected from one of borax, sodium gluconate or sodium citrate, preferably borax.

[0015] The liquid alkali-free accelerator is selected from a fluorine-containing alkali-free accelerator, a fluorine-free alkali-free accelerator, or a sulfur-free alkali-free accelerator; the active Al2O3 content of the liquid alkali-free accelerator is greater than 10%. According to the national standard for liquid accelerators GB / T35159-2017, the product's 6-hour mortar strength is greater than 1.5 MPa, the initial setting time of the net slurry is less than 5 minutes, and the final setting time is less than 8 minutes. Furthermore, the liquid alkali-free accelerator is preferably a fluorine-free alkali-free accelerator. The preferred fluorine-free alkali-free accelerator has better adaptability to the accelerated setting effect between the accelerator and the early strength cementitious material, and can reduce the negative impact of fluoride ions in the accelerator itself on the early strength of the shotcrete.

[0016] Furthermore, the preparation method of the waterproof dense component specifically comprises the following steps:

[0017] Step 1: Mix the inorganic layered carrier with water, stir and shear at 25-35°C and 300-1000 r / min for 1-3 hours to obtain a light yellow suspension solution;

[0018] Step 2: Add the sprayed interface enhancer dropwise into the shear solution obtained in step 1. The addition time is controlled within 0.5 h, the shear rate is adjusted to 300-500 r / min, and shearing is carried out for 1-2 h after the addition is completed;

[0019] Step 3: Add the waterproofing agent to the intermediate obtained in step 2, adjust the shear rate to 100-300 r / min, stir for 1.5-2.5 hours, and finally obtain a light yellow suspended reaction product, which is the waterproof dense component.

[0020] On the other hand, the present invention also provides an application of anti-seepage early-strength shotcrete under over-excavation and water seepage conditions, which specifically includes the following steps:

[0021] (1) Drainage and drainage technology after surrounding rock excavation: After using centralized pressure relief and water diversion in the seepage area of ​​the excavation face, EVA waterproof membrane and high-strength nylon geotextile are used to seal the local seepage area, and the sealing materials are fixed. Finally, a circumferential flexible blind ditch is set on the entire excavation section, and the terminal of the blind ditch is connected to the drainage pipe, and the terminal of the water relief pressure pipe is connected to the flexible drainage blind ditch arranged on the surrounding rock;

[0022] (2) Preparation and construction of spray water-stopping materials for water seepage conditions: Add the spray water-stopping materials to a mixer and mix them thoroughly; load the spray water-stopping materials into the hopper of a dry or tidal spraying machine, mix them with mixing water at the nozzle, and then spray them onto the surface of the surrounding rock treated in step 1;

[0023] (3) Construction of sprayed anti-seepage early-strength shotcrete: anchor rods are embedded in the surface of the sprayed water-stop material, steel arch frames and steel mesh are laid, and then a single-layer or multi-layer wet spraying process is used to spray anti-seepage early-strength shotcrete; the interlayers of the multi-layer wet process sprayed anti-seepage early-strength shotcrete are sprayed with a spray layer interface enhancer.

[0024] In the step (1), the drain pipe is a small advance conduit with a length of 1.5-3.0m and a diameter of 50cm, and the flexible blind ditch is selected from a double-wall perforated corrugated pipe, a soft permeable pipe, or a soft semicircular pipe, and is arranged at a spacing of 5-8m.

[0025] The sprayed water-stopping material in step (2) is composed of a cementitious material, aggregate and a coagulating water-stopping additive, wherein the ratio of cementitious material to aggregate is 1:2-3, and the coagulating water-stopping additive accounts for 3%-8% of the mass of the cementitious material.

[0026] The accelerating water-stopping agent is a mixture of dispersible latex powder and powdered quick-setting material; the powdered quick-setting material is selected from one of aluminum sulfate powder, sodium aluminate powder, amorphous calcium aluminate powder or sodium silicate powder; the mass ratio of the dispersible latex powder to the powdered quick-setting material in the accelerating water-stopping agent is 1-2:3-4.

[0027] The cementitious material in the jet water-stopping material is selected from pure cement or a mixture of cement and silica fume; further, the mass proportion of silica fume in the cementitious material is less than 5% of the total cementitious material; and the cement is selected from silicate cement, aluminate cement or sulphoaluminate cement.

[0028] The aggregate in the jetted waterstop material includes coarse aggregate and fine aggregate, with a mass ratio of coarse aggregate to fine aggregate of 1:1-2. The coarse aggregate is 5-10mm single-particle crushed stone; furthermore, the crushed stone has a needle-like content of less than 10%, a mud content of less than 0.5%, a water absorption rate of less than 0.5%, and a loose bulk void ratio of less than 40%. The fine aggregate is selected from machine-made sand, river sand, or mixed sand, with a fineness modulus of 2.5-3.0, a cumulative 4.75mm sieve residue of less than 5%, and a mud content of less than 0.5%.

[0029] The amount of water used for mixing each cubic meter of sprayed water-stopping material in step (2) is less than 120 kg.

[0030] The spraying thickness of the water-stopping material in step (2) is 50-75 mm.

[0031] The thickness of the sprayed interface enhancer in step (3) is 5-10 mm; further, the spraying pressure of the sprayed interface enhancer is 0.3-0.5 MPa. In step (3), the sprayed interface enhancer is sprayed between concrete layers, and the spraying material is fully sprayed and dispersed on the surface of the sprayed concrete, which can further improve the cohesiveness and impermeability of the concrete surface, better meet the construction performance requirements of thicker sprayed concrete under over-excavation conditions, reduce the rebound loss during the spraying process, and improve the interface mechanics and impermeability of multi-layer wet sprayed concrete.

[0032] Furthermore, in step 3, the thickness of each layer of the anti-seepage and early-strength shotcrete sprayed by the wet spraying process is 15-50 cm.

[0033] Furthermore, in step 3, when the over-excavation thickness is less than 30 cm, anchor rods, steel arch frames, single-layer steel mesh and single-layer anti-permeability early-strength shotcrete are used; when the over-excavation thickness is 30-50 cm, anchor rods, steel arch frames, single-layer steel mesh and double-layer anti-permeability early-strength shotcrete are used; when the over-excavation thickness is 50-100 cm, anchor rods, steel arch frames, single-layer steel mesh and three-layer anti-permeability early-strength shotcrete are used; when the over-excavation thickness is 100-150 cm, anchor rods, steel arch frames, double-layer steel mesh and three-layer anti-permeability early-strength shotcrete are used.

[0034] Furthermore, in step (3), the anchor rod is selected from one of a hollow grouting anchor rod, a mortar anchor rod, a drug coil anchor rod, an expansion shell anchor rod or a water expansion anchor rod; the steel arch frame is selected from one of an I-beam and a steel grid; the steel bar spacing of the steel mesh is 40-60 cm, and the vertical spacing distance of the multi-layer steel mesh is 50-75 cm; the spraying distance of the anti-seepage and early-strength shotcrete is 0.8-1.5 m, the spraying angle formed by the nozzle and the surrounding rock is 85-105°, and the spraying wind pressure is 0.6-1.2 MPa.

[0035] Compared with the prior art, the beneficial technical effects of the present invention are:

[0036] 1. Through reasonable material configuration and construction methods, a kind of anti-seepage early-strength shotcrete and its application in over-excavation water seepage conditions were obtained. In terms of material configuration, a shotcrete water-stopping material targeting surrounding rock water seepage was formed by adding a modified accelerating cohesive water-stopping agent to the dry or tidal shotcrete material with good self-cohesiveness. By rationally controlling the water consumption and spraying thickness of the water-stopping material during the spraying process, the water seepage of the surrounding rock that has been treated with drainage and waterproofing can be further reduced, and the drainage and waterproofing materials taken in the early stage can be well fixed, playing a role in stabilization, sealing and water-stopping. Through the early strength optimization design of the cementitious material and the incorporation of waterproof and dense components, an anti-seepage early-strength shotcrete targeting surrounding rock over-excavation was formed. The concrete material has the characteristics of rapid early strength development, large one-time spraying thickness, excellent anti-seepage performance and high interface bonding strength. It can significantly improve the spraying block drop of shotcrete under over-excavation conditions and further achieve the early support effect of weak surrounding rock earlier.

[0037] 2. In terms of the primary support construction method of the tunnel, for the tunnel working conditions where over-excavation and water seepage exist at the same time, the steps of surrounding rock drainage treatment, spraying water-stopping material construction and multi-layer spraying construction of anti-seepage early-strength shotcrete are carried out in sequence. Among them, the surrounding rock drainage treatment includes centralized pressure relief and water diversion, waterproofing of local water-rich areas and laying of flexible blind ditches on the entire section, which can effectively reduce the water seepage and seepage pressure of the surrounding rock under water seepage conditions, thereby weakening the penetration effect on the subsequent shotcrete. Secondly, the dry or tidal spraying process is used to spray the water-stopping material onto the surface of the weak surrounding rock to achieve the purpose of stabilization, sealing and water-stopping; then, according to the over-excavation thickness, the corresponding multi-layer wet spraying process and interlayer spraying interface enhancer are adopted, which can realize tunnel spraying construction within an over-excavation thickness of 150 cm and ensure the bonding effect between the shotcrete layers and the surrounding rock, without the phenomenon of shotcrete falling off, and comprehensively realize the improvement and guarantee of the construction quality and service performance of shotcrete under water-rich and complex soft surrounding rock conditions.

[0038] 3. The anti-seepage early-strength shotcrete prepared by the present invention has a water seepage resistance grade of P10 or above, a 28-day water absorption rate of less than 0.5%, a 3-hour compressive strength of greater than 6.0 MPa, a 12-hour compressive strength of greater than 15.0 MPa, a 28-day core specimen strength of greater than 45.0 MPa, an interfacial bonding strength of greater than 1.6 MPa, and a single shotcrete thickness of greater than 150 mm. This method can effectively meet the requirements of shotcrete construction, early support strength, and later service performance under complex working conditions with both over-excavation and water seepage. The tunnel primary support construction method under over-excavation and water seepage conditions can effectively simplify the drainage process of water-rich, soft surrounding rock (using only local drainage and drainage, and setting interval blind ditches) and reduce the surrounding rock seepage pressure to below 0.4 MPa. The rebound rate of the shotcrete under over-excavation conditions is less than 10%, significantly reducing the rebound concrete material loss caused by over-excavation shotcrete block drop. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flow chart of the primary support construction method for a tunnel for over-excavation and water seepage conditions according to Application Example 1 of the present invention.

[0040] Figure 2 This is a simplified diagram of the tunnel drainage process for over-excavation and water seepage conditions according to the first application example of the present invention.

[0041] Figure 3 This is a simplified diagram of the multi-layer spraying process for the initial support of a tunnel under over-excavation and water seepage conditions according to the first embodiment of the present invention. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention may be implemented in many different forms, and the present invention should not be construed as being limited to the specific embodiments set forth herein. Instead, these embodiments are provided to explain the principles of the present invention and its practical application, thereby enabling other persons skilled in the art to understand the various embodiments of the present invention and various modifications suitable for specific intended applications.

[0043] In order to verify the excellent performance of the anti-seepage and early-strength shotcrete of the present invention, the present invention also provides Examples 1 to 4 and Comparative Examples 1 to 6.

[0044] The raw materials in Examples 1-4 and Comparative Examples 1-6 are selected as follows:

[0045] Fine aggregate and coarse aggregate (the raw materials are consistent with those selected in Application Examples 1-2 and Comparative Application Examples 1-4): the fine aggregate is mixed sand with a fineness modulus of 2.7, a cumulative sieve residue of 3.5% at 4.75 mm, and a mud content of 0.2%; the coarse aggregate is 5-10 mm single-particle crushed stone with a needle-like content of 7.2%, a mud content of 0.3%, a water absorption rate of 0.2%, and a loose stacking porosity of 32%.

[0046] The silicone waterproofing agent is produced by Nanxiong Dingcheng New Materials Technology Co., Ltd., and its model is FS-150 emulsion type; the fatty acid waterproofing agent is produced by Guangdong Aoboshun Chemical Co., Ltd., and its model is hexadecanoic acid; the cement-based penetrating crystallization waterproofing agent is produced by Shanghai Xiya Chemical Industry and Trade Co., Ltd., and its model is shxy168.

[0047] The water reducer is a mixture of polycarboxylate water reducer and retarder. The polycarboxylate water reducer is produced by Subot Company. Series of polycarboxylic acid high performance water reducers.

[0048] Alkali-free accelerator: Fluorine-containing alkali-free accelerator model JW-1, manufacturer Shanxi Jiawei New Materials Co., Ltd.; fluorine-free and alkali-free accelerator, SBT-N (Ⅱ) liquid accelerator (alkali-free type), Jiangsu Subote New Materials Co., Ltd.; sulfur-free and alkali-free accelerator, produced by Jiangsu Subote New Materials Co., Ltd., SBT-N (Ⅱ) liquid accelerator (sulfur-free type).

[0049] The preparation method of the waterproof dense component in Examples 1-4 and Comparative Examples 1-3 is:

[0050] 1. Mix the inorganic layered carrier with water, stir and shear at room temperature and 800 r / min for 1.0 h to obtain a light yellow suspension solution;

[0051] 2. Add the sprayed interface enhancer dropwise into the shear solution obtained in step 1. The addition time is controlled within 0.5 h, the shear rate is adjusted to 400 r / min, and shearing is continued for 2 h after the addition is completed;

[0052] 3. Add the waterproofing agent to the intermediate obtained in step 2, adjust the shear rate to 200 r / min, and stir for 1.5 h. Finally, a light yellow suspended reactant is obtained, which is the waterproof dense component.

[0053] Example 1 to Example 4

[0054] Table 1 below shows the raw material components and mix ratio parameters of the anti-seepage and early-strength shotcrete provided in Examples 1-4.

[0055] Table 1 Raw material components of anti-seepage early strength shotcrete in Examples 1 to 4

[0056] Unit: kg / cubic tunnel shotcrete

[0057]

[0058]

[0059] The composition of the spray layer interface enhancer in the above Examples 1-4 is shown in Table 2 below:

[0060] Table 2 Composition of spray interface enhancer in Examples 1 to 4

[0061]

[0062] Comparative Example 1

[0063] This comparative example is set based on Example 1, except that 100% Portland cement is used to replace the early strength cementitious material in Example 1, and other conditions are the same as those in Example 1.

[0064] Comparative Example 2

[0065] This comparative example is based on Example 1, except that 100% sulphoaluminate cement is used to replace the early strength cementitious material in Example 2. Other conditions are the same as those in Example 1.

[0066] Comparative Example 3

[0067] This comparative example is set based on Example 1, except that a combination of Portland cement and phosphate cement in a mass ratio of 2:1 is used to replace the early strength cementitious material in Example 2. Other conditions are consistent with Example 1.

[0068] Comparative Example 4

[0069] This comparative example is set based on Example 1, except that 100% silicone waterproofing agent is used to replace the waterproof and dense component in Example 3. Other conditions are consistent with Example 1.

[0070] Comparative Example 5

[0071] This comparative example is set based on Example 1, except that 100% EVA emulsion is used to replace the waterproof and dense component in Example 4. Other conditions are consistent with Example 1.

[0072] Comparative Example 6

[0073] This comparative example is based on Example 1, except that the waterproof dense component does not contain an inorganic layered carrier. The mass composition of the waterproof dense component is 20wt% silicone waterproofing agent + 10wt% spray layer interface enhancer, and the rest is water. Other conditions are consistent with Example 1.

[0074] The waterproof mixture is prepared according to the following steps:

[0075] 1. Add the spray interface enhancer dropwise into the water and shear for 2 hours at room temperature and a shear rate of 400 r / min;

[0076] 2. Add the waterproofing agent to the reactant obtained in step 1, adjust the shear rate to 200 r / min, and stir for 1.5 h. Finally, a white suspended reactant is obtained, which is the waterproof mixture.

[0077] Performance Testing

[0078] In order to verify the fluidity loss and anti-permeability early strength performance of shotcrete provided by Examples 1 to 4 of the present invention, the 1-hour slump loss ratio of concrete was tested with reference to GBT 50080-2016 "Test Method for Performance of Ordinary Concrete Mixtures", and the number and size of test blocks required for the mechanical properties and water seepage resistance tests and other tests were determined by the wet spraying method with reference to Appendix L of GBT 50086-2015 "Technical Specifications for Geotechnical Anchors and Shotcrete Support Engineering". The thickness of the shotcrete material sprayed once during the test was determined. At the same time, the same wet spraying method was used to prepare the comparative shotcrete in the comparative examples 1-4 into comparative test blocks and the single-shot thickness test. The water seepage resistance of shotcrete was evaluated with reference to the water seepage step-by-step pressure method and the water seepage height method in GBT50082-2009 "Test methods for long-term properties and durability of ordinary concrete"; the strength and water absorption of shotcrete specimens were tested with reference to GBT 50081-2019 "Test methods for physical and mechanical properties of concrete"; the interlayer bond strength of shotcrete was evaluated with reference to the core pull-out test in GB 50086-2015 "Technical specification for rock and soil anchors and shotcrete support engineering".

[0079] The performance test results of the shotcrete in Examples 1 to 4 and the shotcrete in Comparative Examples 1 to 6 are shown in Table 3 below.

[0080] Table 3 Performance test results of anti-seepage early strength shotcrete in Examples 1 to 4 and Comparative Examples 1 to 6

[0081]

[0082]

[0083] The water seepage resistance grade of the anti-seepage early-strength shotcrete described in Table 3 is above P10, the 28d water absorption rate is less than 0.5%, the 3h compressive strength is greater than 6.0MPa, the 12h compressive strength is greater than 15.0MPa, the 28d core specimen strength is greater than 45.0MPa, the interface bonding strength is greater than 1.6MPa, and the thickness of one shotcrete is above 150mm. It can meet the problems of low interface bonding strength of shotcrete, small thickness of one shotcrete, poor anti-seepage performance, low hourly strength, etc. under complex working conditions of over-excavation and water seepage, and the comprehensive material performance is significantly improved.

[0084] In Comparative Example 1, no early-strength cementitious material was used, and only pure ordinary Portland cement was used. The 3-hour compressive strength of the shotcrete was only 2.3 MPa, the 12-hour compressive strength was 5.6 MPa, the interface bonding strength was lower than 1.0 MPa, and the early strength was lower than that of Example 1 using the early-strength cementitious material at the same dosage. This shows that the early-strength cementitious material in the present invention has the effect of significantly improving the hourly strength of shotcrete, which is beneficial to improving the early support strength of shotcrete under complex working conditions.

[0085] In Comparative Example 2, pure rapid-hardening cement early-strength gelling material is used to prepare shotcrete. Although the early strength is significantly improved, the later strength is significantly lower than that of Example 2 using early-strength gelling material at the same dosage. This shows that the early-strength gelling material in the present invention can ensure not only the early strength improvement but also the later strength improvement.

[0086] In Comparative Example 3, ordinary Portland cement and phosphate cement are used to replace the early-strength cementitious material to prepare shotcrete. Although the 3-h compressive strength is significantly improved, the early strength after 12 hours is lower than that of Example 1 using the early-strength cementitious material at the same dosage, and the 1-h slump of the concrete is significantly too large. This shows that the early- and late-stage mechanical strengths of the early-strength cementitious material in this aspect are relatively excellent. At the same time, the use of calcium oxide and gypsum components and proportions in the components can significantly improve the working performance of the system and ensure the actual construction time.

[0087] In comparative examples 4 to 5, pure silicone waterproofing agent and EVA emulsion are used to prepare sprayed concrete, and the water seepage resistance is improved, but the effect on the one-day and later strength of the concrete is greater, which is significantly lower than that of Example 1 using a waterproof and dense component at the same dosage. This shows that the waterproof and dense component in the present invention has good adaptability with the early-strength cementitious material described in the present invention while achieving improved water seepage resistance, and has little negative impact on the one-day and later strength.

[0088] In Comparative Example 6, a composition of a waterproofing agent and an interface enhancer is used to prepare shotcrete, and the water seepage resistance is improved. However, the one-day and later strength loss of the concrete is still greater than that of Example 1 using a waterproof and dense component at the same dosage, and the improvement effect on the thickness of the shotcrete after one spraying is also not as good as that of Example 1. This shows that the waterproof and dense component in the present invention uses a combination of an inorganic layered carrier with a waterproofing agent and an interface enhancer, which has a good synergistic improvement effect on waterproofing, density and anti-seepage performance, can significantly increase the thickness of one spraying and has little negative impact on the later strength.

[0089] The following will describe a tunnel primary support construction method for over-excavation and water seepage conditions provided by the present invention through specific application examples 1-2 and application comparison examples 1-4.

[0090] Application Example 1

[0091] An application of anti-seepage early-strength shotcrete in over-excavation and water seepage conditions comprises the following steps:

[0092] Step 1: Drainage and waterproofing after surrounding rock excavation: After using centralized pressure relief and water diversion for areas with large water seepage on the excavation face, use EVA waterproof membrane and high-strength nylon geotextile to seal the local water seepage area, and fix the sealing material with nails. Finally, set up a circular flexible blind ditch for the entire excavation section, connect the terminal of the blind ditch to the longitudinal drainage pipe, and connect the terminal of the water relief pressure pipe to the flexible drainage blind ditch arranged on the surrounding rock;

[0093] The drainage pipe is a small advanced conduit with a length of 1.5m and a diameter of 50cm; the flexible blind ditch is a double-wall perforated corrugated pipe with an arrangement interval of 8m;

[0094] Step 2: Preparation and construction of spray water-stop materials for water seepage conditions: Add aggregate, cementitious material, and accelerating water-stop additive into a mixer in the order of addition and mix thoroughly; load the spray water-stop material into the hopper of a dry or tidal spraying machine, mix it with mixing water at the nozzle, and then spray it onto the surface of the surrounding rock treated in step 1;

[0095] The sprayed water-stopping material is composed of a cementitious material, aggregate, and a setting-accelerating water-stopping additive. The cementitious material to aggregate ratio is 1:2, and the setting-accelerating water-stopping additive accounts for 8% of the cementitious material's mass. The setting-accelerating water-stopping additive is a mixture of dispersible latex powder and a powdered rapid-setting material, with the mass ratio of the dispersible latex powder to the powdered rapid-setting material being 1:3. The powdered rapid-setting material is sodium silicate powder. The cementitious material is pure cement, and the cement is aluminate cement.

[0096] The mixing water of the spray water-stop material for the water seepage condition is 110kg per cubic meter of concrete, and the spraying thickness is 50mm;

[0097] Step 3: Construction of anti-seepage early-strength shotcrete: The over-excavation depth of the tunnel working condition is 120 cm, and anchor rods, steel arch frames, double-layer steel mesh and three layers of anti-seepage early-strength shotcrete are used;

[0098] The anchor rods are hollow grouting anchor rods; the steel arch frame is a steel grid; the steel bar spacing of the steel mesh is 40 cm, and the vertical spacing of the multi-layer steel mesh is 50 cm; the spraying distance of the anti-seepage early-strength shotcrete is 0.8 m, the spraying angle formed by the nozzle and the surrounding rock is 105°, and the spraying wind pressure is 1.2 MPa;

[0099] The three layers of anti-seepage and early-strength shotcrete are sprayed with a spray layer interface enhancer between the layers. The composition and mass ratio of the spray layer interface enhancer are: 40% vinyl acetate-vinyl chloride-acrylate copolymer emulsion + 0.1% Wenlun glue + 49.9% nano zeolite; the spraying pressure is 0.5MPa and the spraying thickness is 5mm.

[0100] The anti-seepage and early-strength shotcrete in step 3 is the same as that in Example 1.

[0101] Application Example 2

[0102] An application of anti-seepage early-strength shotcrete in over-excavation and water seepage conditions comprises the following steps:

[0103] Step 1: Drainage and waterproofing after surrounding rock excavation: After using centralized pressure relief and water diversion for areas with large water seepage on the excavation face, use EVA waterproof membrane and high-strength nylon geotextile to seal the local water seepage area, and fix the sealing material with nails. Finally, set up a circular flexible blind ditch for the entire excavation section, connect the terminal of the blind ditch to the longitudinal drainage pipe, and connect the terminal of the water relief pressure pipe to the flexible drainage blind ditch arranged on the surrounding rock;

[0104] The drainage pipe is a small advance conduit with a length of 3.0m and a diameter of 50cm; the flexible blind ditch is a soft permeable pipe with a spacing of 5m;

[0105] Step 2: Preparation and construction of spray water-stop materials for water seepage conditions: Add aggregate, cementitious material, and accelerating water-stop additive into a mixer in the order of addition and mix thoroughly; load the spray water-stop material into the hopper of a dry or tidal spraying machine, mix it with mixing water at the nozzle, and then spray it onto the surface of the surrounding rock treated in step 1;

[0106] The jetted water-stopping material is composed of a cementitious material, aggregate, and a setting-accelerating water-stopping additive, wherein the cementitious material to aggregate ratio is 1:3, and the setting-accelerating water-stopping additive accounts for 3% of the cementitious material mass. The setting-accelerating water-stopping additive is a mixture of dispersible latex powder and powdered rapid-setting material, wherein the mass ratio of the dispersible latex powder to the powdered rapid-setting material is 2:3, and the powdered rapid-setting material is amorphous calcium aluminate powder. The cementitious material is a mixture of cement and silica fume, and the cement is Portland cement.

[0107] The mixing water consumption of the spray water-stop material for the water seepage condition is less than 120kg per cubic meter of concrete, and the spraying thickness is 60mm;

[0108] Step 3: Shotcrete construction: The over-excavation depth of the tunnel working condition applied is 25cm, and anchor rods, steel arch frames, single-layer steel mesh and single-layer anti-seepage and early-strength shotcrete are used.

[0109] The anchor rod is an expansion shell anchor rod; the steel arch frame is an I-beam; the steel bar spacing of the steel mesh surface is 60 cm; the spraying distance of the anti-seepage early strength shotcrete is 1.5 m; the spraying angle formed by the nozzle and the surrounding rock is 105°; the spraying wind pressure is 0.6 MPa;

[0110] The anti-seepage and early-strength shotcrete in step 3 is the same as that in Example 1.

[0111] Comparative Application Example 1

[0112] This comparative example is based on the application of an anti-seepage early-strength shotcrete under over-excavation and water seepage conditions set in Application Example 1. The difference is that this comparative example does not take step 2 in Application Example 1, and the other steps and over-excavation thickness are the same as Example 1.

[0113] Application Comparative Example 2

[0114] This comparative example is based on the application of an anti-seepage early-strength shotcrete set in the over-excavation and water seepage working condition set in Application Example 1. The difference is that in step 2 of this comparative example, ordinary shotcrete is used instead of the shotcrete water-stop material. The raw materials of the ordinary shotcrete are composed of silicate cement, aggregate and powdered accelerator sodium aluminate. The other steps and over-excavation thickness are the same as those in Example 1.

[0115] Application Comparative Example 3

[0116] This comparative example is based on the application of an anti-seepage early-strength shotcrete under over-excavation and water seepage conditions set in Application Example 1. The difference is that this comparative example does not adopt the spraying of the spray layer interface enhancer between the layers of the multi-layer wet shotcrete in step 3 of Application Example 1. The other steps and over-excavation thickness are the same as those in Example 1.

[0117] Comparative Application Example 4

[0118] This comparative example is based on the application of an anti-seepage early-strength shotcrete under over-excavation and water seepage conditions set in Application Example 1. The difference is that in step three of this comparative example: a mixture of a copolymer emulsion and a viscosity-increasing component is sprayed between layers of multi-layer wet shotcrete instead of a spray layer interface enhancer, and the mixture consists of 60% vinyl propionate polymer emulsion, 0.5% xanthan gum and 39.5% water. The other steps and over-excavation thickness are the same as those in Example 1.

[0119] Performance Testing

[0120] In order to verify the drainage effect and jetting construction performance of the tunnel primary support construction method for over-excavation and water seepage conditions provided by the above-mentioned Application Examples 1 to Application Examples 2 and Application Comparison Examples 1 to Application Comparison Examples 2 of this aspect, the water seepage pressure behind the primary support structure before and after construction, the rebound during the jetting process, and the hardened surface conditions of the primary support concrete due to jetting blocks were tested.

[0121] Table 4 Construction parameter results of the primary support construction method of application examples 1 to 2 and comparative examples 1 to 4

[0122]

[0123] Note: The quality of the initial shotcrete hardening is judged by the hardening flatness and concrete penetration;

[0124] It can be seen from the construction parameter test results described in Table 4 that, compared with application comparison examples 1 to 4, the tunnel primary support construction method for over-excavation and seepage conditions of the present invention can reduce the primary support seepage pressure to below 0.4 MPa, control the jet rebound rate to below 10%, and there is no jet block drop phenomenon. It can better improve the problems of obvious water seepage of the primary support structure, large jet block drop, and high rebound rate under the complex working conditions of over-excavation and seepage. The comprehensive construction method has high efficiency and good quality assurance rate.

[0125] In the application of comparative example 1, no spraying water-stopping material was adopted. Although the seepage pressure was significantly reduced, the seepage and water-stopping conditions of the surrounding rock were not improved, resulting in local seepage in the arch shoulders after spraying, and also causing an increase in the rebound rate and the occurrence of spraying blocks. This shows that the spraying water-stopping material in the primary support construction method of the present invention can significantly improve the seepage conditions of the surrounding rock and ensure the construction quality of the subsequent shotcrete.

[0126] In the application of comparative example 2, ordinary wet sprayed concrete was used to carry out spray water stopping in step 2. The water seepage and water stopping effect of the surrounding rock were also not improved, resulting in water seepage in the local part of the arch, and the compatibility with the anti-seepage and early-strength sprayed concrete was general, resulting in an increase in the spray rebound rate and the falling of the arch. This shows that the spray water-stopping material in the primary support construction method of the present invention has good compatibility with the anti-seepage and early-strength sprayed concrete, and has good comprehensive performance in reducing the spray rebound rate and the spraying effect of key support parts such as the arch and arch shoulders.

[0127] When comparative example 3 was applied, the spraying interface enhancer was not sprayed on the shotcrete layer. The spraying block rate was significantly increased and the rebound rate was increased. Local water seepage still existed in the vault part. This shows that the spraying interface enhancer between layers in the multi-layer shotcrete process in the primary support construction method of the present invention significantly reduced the block falling phenomenon in the spraying process and improved the anti-seepage performance between multiple wet shotcrete layers.

[0128] Comparative Example 4 uses an interface material of a mixture of an interlayer spray copolymer emulsion and a viscosity-increasing component, but it fails to improve the problem of falling blocks at key parts of the vault during the spraying process. The spraying rebound rate is relatively high, and there is a small amount of water seepage on the vault. This shows that the spraying interface enhancer in the primary support construction method of the present invention has a good effect of improving the interlayer cohesion and anti-seepage performance of the shotcrete. The presence of nanoparticles in the spray layer interface enhancer also improves the compatibility with the anti-seepage early-strength shotcrete.

[0129] While the invention has been shown and described with reference to particular embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the claims and their equivalents.

Claims

1. An anti-seepage and early-strength shotcrete, characterized in that: The raw materials include the following components: early-strength cementitious materials, fine aggregate, coarse aggregate, waterproof and dense component, water-reducing agent, liquid alkali-free accelerator, and water. The early-strength cementitious materials contain 400kg-500kg of material per cubic meter; the fine aggregate contains 850kg-950kg of material, the coarse aggregate contains 850kg-950kg of material, the liquid alkali-free accelerator contains 30kg-45kg of material, the waterproof and dense component accounts for 5%-10% of the mass of the early-strength cementitious materials, the water-reducing agent accounts for 0.5%-1.5% of the mass of the early-strength cementitious materials, and the water-cement ratio is 0.32-0.

38. The waterproof and dense component is composed of a waterproofing agent, an inorganic layered carrier, a spray interface enhancer, and water; the inorganic layered carrier is an inorganic silicate layered mineral; the spray interface enhancer is a mixture of a copolymer emulsion, a tackifying component, and nanoparticles; the mass ratio of the waterproofing agent, the inorganic layered carrier, the spray interface enhancer, and water is 20-30:1-5:5-10:55-75; The mass ratio of the copolymer emulsion, the viscosity-increasing component and the nanoparticles in the spray layer interface enhancer is 40-80:0.1-1.0:20-40.

2. The anti-seepage and early-strength shotcrete according to claim 1, characterized in that: The inorganic layered carrier is selected from one of sepiolite, attapulgite, lithium magnesium silicate, kaolin or bentonite.

3. The anti-seepage and early-strength shotcrete according to claim 1, characterized in that: The waterproofing agent is selected from a silicone waterproofing agent, a fatty acid waterproofing agent or a cement-based penetrating crystallization waterproofing agent.

4. The anti-seepage and early-strength shotcrete according to claim 1, characterized in that: The copolymer emulsion is selected from one of vinyl propionate polymer emulsion, pure acrylic acid copolymer emulsion, styrene-acrylate copolymer emulsion, vinyl acetate-vinyl versatate copolymer emulsion, vinyl acetate-ethylene copolymer emulsion or vinyl acetate-vinyl chloride-acrylate copolymer emulsion; the viscosity-increasing component is selected from one of hydroxypropyl methylcellulose ether, hydroxyethyl methylcellulose ether, gellan gum, xanthan gum, diutan gum, weinlun gum, polyacrylamide, polyvinyl alcohol or polyethylene glycol; the nanoparticles are one of nano-silicon dioxide, nano-aluminum oxide, nano-calcium carbonate, nano-zeolite, nano-magnesium oxide, nano-titanium dioxide or nano-zinc oxide.

5. The anti-seepage and early-strength shotcrete according to claim 1, characterized in that: The early strength gelling material is a mixture of silicate cement, rapid hardening cement, calcium oxide and gypsum, wherein the mass ratio of silicate cement, rapid hardening cement, calcium oxide and gypsum is 8-12:3-6:1-3:1-3.

6. The anti-seepage and early-strength shotcrete according to claim 5, characterized in that: The rapid-hardening cement is selected from aluminate cement, sulphoaluminate cement or phosphate cement, and the gypsum is selected from dihydrate gypsum, hemihydrate gypsum, anhydrous gypsum, phosphogypsum or desulfurized gypsum.

7. The anti-seepage and early-strength shotcrete according to claim 1, characterized in that: The coarse aggregate is 5-10 mm single particle size crushed stone, the fine aggregate is selected from one of machine-made sand, river sand or mixed sand, and the liquid alkali-free accelerator is selected from one of fluorine-containing alkali-free accelerator, fluorine-free alkali-free accelerator or sulfur-free alkali-free accelerator.

8. The anti-permeability and early-strength shotcrete according to claim 1, characterized in that: The water reducer is a mixture of a polycarboxylate water reducer and a retarder, wherein the retarder accounts for 10%-20% of the mass proportion of the polycarboxylate water reducer; the retarder is selected from one of borax, sodium gluconate or sodium citrate.

9. The anti-permeability and early-strength shotcrete according to claim 1, characterized in that: The preparation method of the waterproof dense component specifically comprises the following steps: Step 1: Mix the inorganic layered carrier with water, stir and shear at 25-35°C and 300-1000 r / min for 1-3 hours to obtain a light yellow suspension solution; Step 2: Add the sprayed interface enhancer dropwise into the shear solution obtained in step 1. The addition time is controlled within 0.5 h, the shear rate is adjusted to 300-500 r / min, and shearing is carried out for 1-2 h after the addition is completed; Step 3: Add the waterproofing agent to the intermediate obtained in step 2, adjust the shear rate to 100-300 r / min, stir for 1.5-2.5 hours, and finally obtain a light yellow suspended reaction product, which is the waterproof dense component.

10. Application of the anti-seepage early-strength shotcrete according to any one of claims 1 to 9 in over-excavation and water seepage conditions, characterized in that: The specific steps include: (1) Drainage and drainage technology after surrounding rock excavation: After using centralized pressure relief and water diversion in the seepage area of ​​the excavation face, EVA waterproof membrane and high-strength nylon geotextile are used to seal the local seepage area, and the sealing materials are fixed. Finally, a circumferential flexible blind ditch is set on the entire excavation section, and the terminal of the blind ditch is connected to the drainage pipe, and the terminal of the water relief pressure pipe is connected to the flexible drainage blind ditch arranged on the surrounding rock; (2) Preparation and construction of spray water-stop materials for water seepage conditions: Add the spray water-stop materials into the mixer and mix thoroughly; Load the water-stopping material into the hopper of the dry or tidal jetting machine, mix it with the mixing water at the nozzle, and then spray it onto the surface of the surrounding rock treated in step 1; (3) Construction of sprayed anti-seepage early-strength shotcrete: anchor rods are embedded in the surface of the sprayed water-stop material, steel arch frames and steel mesh are laid, and then a single-layer or multi-layer wet spraying process is used to spray anti-seepage early-strength shotcrete; the interlayers of the multi-layer wet process sprayed anti-seepage early-strength shotcrete are sprayed with a spray layer interface enhancer.

11. Application of the anti-seepage early-strength shotcrete according to claim 10 in over-excavation and water seepage conditions, characterized in that: The sprayed water-stopping material in step (2) is composed of a cementitious material, aggregate and a coagulating water-stopping additive, wherein the ratio of cementitious material to aggregate is 1:2-3, and the coagulating water-stopping additive accounts for 3%-8% of the mass of the cementitious material.

12. Application of the anti-seepage early-strength shotcrete according to claim 11 in over-excavation and water seepage conditions, characterized in that: The accelerating water-stopping agent is a mixture of dispersible latex powder and powdered quick-setting material; the powdered quick-setting material is selected from one of aluminum sulfate powder, sodium aluminate powder, amorphous calcium aluminate powder or sodium silicate powder; the mass ratio of the dispersible latex powder to the powdered quick-setting material in the accelerating water-stopping agent is 1-2:3-4.

13. Application of the anti-seepage early-strength shotcrete according to claim 10 in over-excavation and water seepage conditions, characterized in that: The spraying thickness of the water-stopping material in step (2) is 50-75 mm; the spraying thickness of the spray layer interface enhancer in step (3) is 5-10 mm.

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