Water-seepage-free, stuffy, humid and permanently-sprayed concrete supporting roadway white spraying coating and construction method

[0024] The preparation method of the coating A comprises the following steps:

[0025] Adding deionized water, butyl acrylate, methacrylate, acrylic acid, styrene and inorganic silicon solution in turn under low-speed stirring, heating to 70℃ and stirring for 10min, then adding perfluoroalkyl acrylate, sodium dodecyl benzene sulfonate, nonylphenol polyoxyethylene ether (OP-10) emulsifier, hydroxyethyl acrylate and ammonium persulfate, heating to 85℃ and stirring for 1.5h, then cooling to 50℃. Adding K20 mildew inhibitor while stirring, adjusting pH to 7.5-8.0 with sodium bicarbonate, finally adding polysiloxane emulsion, stirring at low speed for 15-20min, and filtering with 200 mesh filter.

[0026] The preparation method of the coating B comprises the following steps: stirring and mixing cement, fly ash, talcum powder, heavy calcium carbonate, hydroxypropyl methylcellulose ether, white quartz sand, additives, VAE latex powder and water to form slurry, and grinding the slurry to a fineness of 80μ m-120μ m..

[0027] The construction method of white paint spraying for the tunnel with permanent shotcrete support without water seepage, sweltering heat and humidity comprises the following steps:

[0028] 1) applying the first coating layer: coating the coating A on the roadway wall;

[0029] 2) coating the second coating layer: after the coating A in step 1 is dried, coating the mixture of coating A and coating B on the roadway wall.

[0030] The coating methods in step 2 and step 3 are spraying.

[0031] The first coating layer is sprayed by a small electric airless sprayer, the second coating layer is sprayed by a heavy airless hydraulic sprayer, and the thickness is more than or equal to ≥4mm in a crisscross way, and the spraying range is the area where the tunnel wall is more than 1m away from the bottom plate. The mass ratio of coating A to coating B in the mixture of coating A and coating B is 1:3, and the mixture of coating A and coating B is mixed at this ratio to form a viscous, high-concentration white water-resistant and hydrophobic coating.

[0032] The first coating layer is sprayed with 007 spray gun and 2-series nozzle. When spraying, the spray gun nozzle needs to be 500-600 mm away from the tunnel wall, the extension of the spray pipe is within 30m, and the extension of the spray rod is 2.4-2.6m m.

[0033]The first coating layer in the invention is an alkali-resistant layer, which mainly plays the role of sealing the roadway and spraying concrete, isolating the concrete from direct contact with air and moisture, and preventing the concrete from returning to sand and alkali (mildew). It only needs uniform spraying and complete coverage, and there is no specific spraying thickness requirement. In addition, coating A is an aggregate-free water-based coating, which is sprayed by a small electric airless spraying machine such as GRACO-390PC. This equipment has moderate pressure and high efficiency, and it will not cause coating splash and rebound when spraying aggregate-free water-based coating, wasting coating and increasing cost. The distance between the spray gun and the roadway wall is 500 ~ 600 mm, because the spraying effect is poor if the distance is too far, and the coating cannot completely cover the shotcrete layer of the roadway. If the distance is too close, the coating will bounce and splash, and the utilization rate of the coating will be low. The reason for choosing 007 spray gun is that there is a very fine filter screen in 007 spray gun, and the spray gun is equipped with a self-locking device, so the operators can work for a long time without fatigue, and the spraying efficiency is high. However, this spray gun requires that there should be no more than 600 meshes of fine aggregate in the paint, just because the paint A belongs to water-based paint, and there is no filler aggregate. Therefore, choosing this spray gun for spraying has the highest construction efficiency and the best effect. The reason for choosing 2-series nozzle is that among all nozzles, 2-series nozzle has the best atomization effect and the most uniform sprayed coating. The nozzle extension is within 30m, because the pressure will obviously decrease after the nozzle extension exceeds 30m, which will affect the spraying effect. The length of spraying rod is 2.5m because the width and height of tunnel section in underground mine are generally within 4.2m and 4.8m. If the length of spraying rod is 2.5m plus the height of operators, it can be effectively sprayed on the roof and side wall of tunnel. If it is longer, it will be difficult to operate. If it is too short, it will not reach the roof of tunnel. Spraying at a certain inclination angle is to prevent paint from dripping on people during spraying, and slow spraying at a uniform speed is to ensure uniform spraying effect.

[0034] In the present invention, GRACO GH-833 heavy airless hydraulic spraying machine is adopted, which has high spraying pressure and large flow rate, so as to exert its construction efficiency for maximum efficiency. In addition, 1/4 high-pressure hose is used, and SPQ911 spray gun is adopted, because this kind of spray gun is suitable for spraying paint containing coarse aggregate filler, its spraying efficiency is high, and it is not easy to block the gun. If other spray guns are used, it is easy to block the gun and its service life is short. The length of spray joint is 2.5m；; Because the width and height of underground mine roadway section are generally within 4.2m and 4.8m, the nozzle extension to 2.5m plus the height of the operators can be effectively sprayed on the roadway roof and side wall, but it is difficult to operate if it is longer, and the roadway roof cannot be sprayed if it is too short. When the second coating is sprayed, the spray gun nozzle is 800～1200mm away from the roadway wall, and the pressure is normal when the nozzle is extended to 150m. Otherwise, the pressure can't keep up. When the spray gun is received and the nozzle extension range is less than 90m, the 6-series nozzle can be used to maximize its spraying efficiency.

[0035] When spraying, the cross-type spraying refers to spraying it longitudinally forward, longitudinally backward, transversely to the right and transversely to the left at a constant speed and slowly along the extension direction of the roadway at a certain inclination angle, which is a cross-type spraying. Each time, the paint sprayed in the previous time should be dried before the next spraying. The total thickness of the spraying layer is not less than 4mm, and the spraying range is the area (including the vault) where the roadway wall is more than 1m away from the floor. Cross-spraying is adopted because most of the tunnel walls in underground mines are uneven, and the tunnel walls cannot be completely covered by spraying only from one direction. Only by cross-spraying from four directions can the corners and potholes of the tunnel walls be completely covered by spraying.

[0037] Example 1

[0038] White spraying paint for permanent shotcrete supporting roadway without water seepage, sweltering heat and humidity comprises paint A and paint B, wherein paint A comprises the following raw materials in parts by weight: 0.3 part of K20 mildew inhibitor, 6 parts of inorganic silicon solution, 55 parts of butyl acrylate, 36 parts of methacrylate, 6 parts of acrylic acid, 10 parts of styrene, 10 parts of perfluoroalkyl acrylate, 2 parts of sodium dodecyl benzene sulfonate, and nonylphenol polyoxyethylene ether (OP-10).

[0039] The preparation method of coat5ming A is as follows: deionized water, butyl acrylate, methacrylate, acrylic acid, styrene, and inorganic silicon solution are sequentially added in the state of low-speed stirring, and then stirred for 5 minutes after heating to 80℃, and then perfluoroalkyl acrylate, sodium dodecyl benzene sulfonate, nonylphenol polyoxyethylene ether (OP-10) emulsifier, hydroxyethyl acrylate, and ammonium persulfate are continuously added, and stirred for 1 hour after heating to 75℃. Then cooling to below 50℃, adding K20 mildew inhibitor while stirring, adjusting pH to 8.0 with sodium bicarbonate, finally adding polysiloxane emulsion, stirring at low speed for 15min, filtering with 200 mesh filter, and discharging.

[0040] Coating B comprises the following raw materials in parts by weight: 45 parts of cement, 5 parts of fly ash, 7 parts of talcum powder, 60 parts of white quartz sand, 10 parts of heavy calcium carbonate, 0.45 part of hydroxypropyl methylcellulose ether, 0.6 part of assistant, 5 parts of VAE latex powder and 75 parts of water, wherein the white quartz sand comprises 6 parts of 100-mesh white quartz sand and 3 parts of 70-mesh white quartz sand.

[0041] The preparation method of coating B is as follows: cement, fly ash, talcum powder, heavy calcium carbonate, hydroxypropyl methylcellulose ether, white quartz sand, additives, VAE latex powder and water are stirred and mixed according to the above ratio to form slurry, and the slurry is ground to a fineness of 120μm m..

[0042] Example 2

[0043] The waterproof, sweltering and humid permanent shotcrete-supported roadway white-spraying coating comprises coating A and coating B, wherein coating A comprises the following raw materials in parts by weight: K20 mildew inhibitor 0.1, inorganic silicon solution 5, butyl acrylate 54, methacrylate 34, acrylic acid 4, styrene 8, perfluoroalkyl acrylate 5, sodium dodecyl benzene sulfonate 1 and nonylphenol polyoxyethylene ether (OP-10).

[0044] Coating B comprises the following raw materials in parts by weight: 35 parts of cement, 3 parts of fly ash, 7 parts of talcum powder, 70 parts of white quartz sand, 10 parts of heavy calcium carbonate, 0.45 part of hydroxypropyl methylcellulose ether, 0.4 part of assistant, 3 parts of VAE latex powder and 65 parts of water, wherein the white quartz sand comprises 6 parts of 120 mesh white quartz sand and 3 parts of 80 mesh white quartz sand.

[0045] The preparation method of coating A is as follows: deionized water, butyl acrylate, methacrylate, acrylic acid, styrene and inorganic silicon solution are added in sequence according to the above ratio in a low-speed stirring state, and then stirred continuously for 15min after heating to 60℃, then perfluoroalkyl acrylate, sodium dodecyl benzene sulfonate, nonylphenol polyoxyethylene ether (OP-10) emulsifier, hydroxyethyl acrylate and ammonium persulfate are added continuously after heating to 95℃ for constant temperature. Then cooling to below 50℃, adding K20 mildew inhibitor while stirring, adjusting pH to 7.9 with sodium bicarbonate, finally adding polysiloxane emulsion, stirring at low speed for 20min, and filtering with 200 mesh filter.

[0046] The preparation method of coating B is as follows: cement, fly ash, talcum powder, heavy calcium carbonate, hydroxypropyl methylcellulose ether, white quartz sand, additives, VAE latex powder and water are stirred and mixed according to the above ratio to form slurry, and the slurry is ground to a fineness of 80μm m..