Shotcrete concrete spraying technology in tunnel construction

Shotcrete concrete spraying technology is using concrete spraying machine/shotcrete machine, the concrete mixed with accelerator sprayed to the rock surface, forming a support structure, the surrounding rock has some support role.

A. Shotcrete concrete spraying technology

Shotcrete concrete spraying technology includes dry spraying, wet spraying, wet spray and mix spraying. The main difference is the order of addition of materials, especially water and accelerators.

The disadvantage of dry concrete spraying is dust big, big rebound, adding water by the valve on the nozzle control. The water / cement control range depends on the skill level of the operator.

However, dry sprayers are easy to clean and maintain.

Damp-concrete spraying is adding a little water first to make the concrete damp, then adding cement, it could reduce the dust on working. However in this way it still adding much water by the valve on the nozzle.

Wet concrete spraying is easy to control the quality, and it is small dust and rebound during operating. However it is high requirement on the shotcrete machine and it is hard to clean the machine and maintenance. For thicker soft rock and leaking tunnel spraying project, it is not recommended to use wet spraying machine.

Shotcrete concrete spraying technology in tunnel construction is to add water and part of the sand, and then add all the cement forced mixing to form a shell, adding water and water reducer to form the SEC mortar; the other part of the sand, accelerators forced mixing. The two materials were then conveyed to a mixing hose and then sprayed using a mortar pump and a dry jet concrete machine.

Because of the concrete spraying technology in tunnel, the strength of the concrete is different, the dry concrete spraying and the wet concrete spraying technique have low strength and are normal in the C20, wet concrete spraying and shotcrete concrete spraying and reaching C30-C35.

B. Shotcrete concrete spraying process and function

Shotcrete concrete spraying process

Preparation before construction --- Working face --- Marking with built-in concrete coating thickness --- Spray machine ready --- Connect air, water and power, and test the machine --- The first time spraying concrete ---- Re-spray the concrete --- check the quality of work

Shotcrete concrete spraying function

One. Support rock b. Uninstall c. Fill and enhance the surrounding rock d. Cover the surrounding rock e. Loose surrounding rock f. Assign external force.

Any questions about shotcrete concrete spraying technology in tunnel construction, you can tell us freely. Email address: sales@leadcrete.com.