Shotcrete machine requirement for injection process

1. Ejection port to keep the ejection faces perpendicular. In cases of fractured low recess should be sprayed to fill level, and then the normal injection.

2. Injection port to the ejection surface a distance not more than one meter.

3. Nozzle according to generally helical path running spiral circle diameter of 30mm, a half circle around the pressure, even slow-moving.

4. Before injection, it should be divided into sections, in sequence.

  a. Horizontal and inclined roadway sections divided: typically 1.5 ~ 2m, injection after the first order of the arch wall. When spraying walls, from the base of the wall starts from the bottom up. When the spray arch, the arch after the first vault.

  b. Single-line spray Shaft excavation work should be driving section into several small pieces of 1.5 to 2m, and the injection start with the next paragraph starts from the bottom up.

  c. Adjacent segments should Jiecha injection into skew Jiecha a width of twice the thickness.

5. In jet operations, such as plugging occur suddenly or stop the wind, the power outage, you should immediately turn off the valve nozzle, the nozzle is placed downwards to prevent water back to the conveying tube.

6. Shotcrete to strictly control the water-cement ratio, if found concrete surface is dry, loose, fall, slip and crack, should be timely removal and fill spray.

7. When sprayed concrete thickness is greater than 100mm, should be stratified injection and comply with the following provisions:

  a. A spray concrete thickness: Wall of 7 ~ 100mm, the arch is 35 ~ 50mm.

  b. Second injection after the first injection should be the final setting of concrete. If the interval exceeds 2h, water should wet concrete surface, ensure good contact between the concrete layer.

8. With metal mesh or reinforced shotcrete time job, to comply with the following provisions:

  a. A metal mesh to be laid over the roadway contours and maintaining a gap of less than 30mm and rock.

  b. A metal mesh grid, typically less than 150 × 150mm, metal mesh and wire diameter of the steel is generally 2.5*10mm.

  c. Metal banding and bolt to connect securely.

  d. Spray operations, if found off the concrete with metal grid to live, should be promptly removed fill spray.

  e. If the metal mesh blasting upset, should sort out good and then sprayed concrete.

9. Operating procedures must have been completed on the roadway spray sprinkler maintenance seriously. Do sprayed concrete (shotcrete) in accordance with quality acceptance standard test block (200*200*200mm), test spray strength to reach more than 150 to 200.