During the spraying operation of the small hydraulic wet shotcrete machine, the water-cement ratio and the amount of quick-setting agent should be strictly controlled. After spraying, the surface of the spray layer should be smooth and smooth, without dry spots or slipping flow; the spraying of the wet shotcrete machine should be segmented , Division, block, according to the wall first after arch, from bottom to top.
The length of the section does not exceed 6m, the section is first down then up, and the size of the block is 2m × 2m, so as to reduce the occurrence of sliding or shedding of the concrete due to gravity; when the wet sprayer sprays the concrete, it can be spiral Moving forward, you can also use S-shaped round-trip moving forward; control the distance and angle of the nozzle and the receiving surface, the distance is preferably 0.8 ~ 1.2m, too large or too small will increase the rebound amount, the nozzle and the receiving surface Vertical, and slightly biased to the part just sprayed (inclination angle should not be greater than 100), the rebound amount is the smallest and the spraying effect is the best. For the rock depressions, spray first and spray more, and protruding parts spray later or less; adjust the wind pressure and water pressure. If the wind pressure is too large, the springback will increase, and if it is too small, the concrete density will be poor; spraying operation It should be carried out in layers. One shot is too thick, it will cause expansion, affect the adhesion and cohesion of the concrete, and it is easy to cause delamination or self-weight to cause large slumps; the first shot is too thin, the coarse aggregate should not be sticky The connection is firm, increasing the amount of rebound; therefore, a thick or too thin shot will affect the quality of the shot, but the thickness of the initial shot should not be less than 4 ~ 6cm; after the concrete spraying operation of the wet sprayer is completed, the product in the sprayer and the delivery pipe The material must be cleaned in time; the shotcrete operation of the wet shotcrete machine must closely follow the excavation surface, and the interval between the next blasting and the completion of the shotcrete operation surface should not be less than 4h;
The principle of spraying concrete by wet shotcrete machine is to mix the aggregate, cement and water uniformly according to the design ratio, and use the wet shotcrete machine to press the mixed concrete mixture to the spray head, and then fill the spray head with accelerating agent and spray The quality of wet sprayed concrete is easier to control, and the amount of dust and rebound during the spraying process is less.
