Centrifugal spraying technology is to pump the pre-prepared paste-like repair material to the high-speed rotary nozzle driven by compressed air located in the inspection well, and the material is evenly thrown to the inner wall of the inspection well under the action of high-speed rotating centrifugal force, and the rotating nozzle moves up and down at a certain speed along the central axis in the inspection well under the traction of the lifting winch, so that the repair material forms a continuous and dense lining layer on the wall of the well, until the lining layer formed by spraying reaches the design thickness.
1. The lining design should follow the following basic principles:
1. When there is obvious water leakage before the inspection well is repaired, the water should be blocked first;
2. After repair, the structure of the inspection well should be able to meet the requirements of bearing capacity, anti-seepage, anti-corrosion and size;
3. The lining constructed by centrifugal spraying method usually refers to the section of the well wall between the bottom of the manhole cover and the bottom of the well, and the bottom of the well, the launder and the horizontal roof can be repaired by manual spraying or scraping;
4. The minimum thickness of the cement-based lining of the drainage inspection well should not be less than 15mm, and the thickness of the lining should not be less than 20mm when there is a requirement for closed water.
5. When the rectangular inspection well is repaired structurally, steel bars (or other tensile strength) should be added to the lining to improve the bending performance of the lining.
2. Before the cement-based lining repair of the inspection well, it should be pretreated and meet the following requirements:
1. When cleaning the inspection well, measures should be taken to avoid the large hard debris falling from the well wall from being washed into the pipeline;
2. The treated well wall should be free of sludge, garbage, grease and organic coating and other attachments, and the rot on the well wall.
The etched layer and loose structure should be cleaned;
3. When there is water leakage in the well, the water should be stopped according to the on-site situation.
4. Defects such as depressions, holes and cracks exposed after substrate treatment should be filled with cement mortar.
5. The cavities around the well that have been proved should be filled by grouting and other methods.
6. When the inspection well is sinking as a whole, the foundation can be strengthened to make its foundation stable.
7. The lining slurry should be stirred according to the water-to-material ratio recommended by the material supplier, and the stirred slurry should be specified.
Occasional use;
8. Before spraying construction, ensure that the substrate is in a wet state, but there shall be no obvious water droplets or flowing water; While.
When the ambient temperature of the construction is higher than 35, cooling measures should be taken.
9. When the centrifugal spraying method is used for repair, the following steps should be followed:
10. Place the centrifugal rotary sprayer in the center of the well, start the rotary sprayer, and start the mortar conveying after its operation is stable.
Pump, after the slurry is evenly thrown out from the rotary sprayer, the crane arm is operated to make the rotary spraying machine smoothly descend to the bottom of the well.
After switching the direction, the rotary blowout is lifted to the wellhead to complete a spraying return, and so on and so forth.
3. Design thickness;
1. In the process of centrifugal spraying, the lowering and lifting speed of the rotary sprayer should not be greater than 3m min;
2. If the centrifugal spraying process is interrupted for some reason, the equipment should be cleaned up in time to avoid blockage;
3. After the lining is sprayed, the original shape of the lining is retained, and the surface can also be pressed and wiped according to the requirements.
4. The joint between the bottom of the well and the wall of the well should be rounded and transitioned, and the thickness of the bottom lining of the well should not be less than 20mm.
5. The lining should be cured in a windless and humid environment to avoid cracking caused by rapid evaporation of water.