 Jet Grouting Drilling Method -
Jet grouting drilling - single, double, triple type
Under pressure of 100 to 600 bar, sand, gravel or slit are injected and interspread with a cement suspension.
The jet grouting drilling rods of the jet grouting single rod type consist of only one injection string. As the drilling head is used simultaneously as a monitor, the drilling bit is equipped with appropriate nozzles. During injection process the automatic valve seals the path to the drilling bit.
Jet grouting is done while the drilling rods are withdrawn. Withdrawal speed has a crucial influence on the column diameter, which quite possibly varies in size.
To increase injection depth and column diameter of jet grouting, the column is coated with air (double method) using particular jet grouting rods. The internal high-pressure string transports cement suspension, the external string transports air. At the end of the drilling rods is the nozzle combine the suspension to the thin stream. This stream is coated with air, which guarantees the success of the grouting.
Also in jet grouting with double type, the grouting is always done while rods are withdrawn and the automatic valve is closed. Another valve ensures flushing of the drilling bit during back-drill.
Triple jet grouting rods transport additional water in a third string to the drill bit (no illustration).
Jet Grouting Drilling Method |
| single type |
Ø 88,9 / 3,5 |
| double type |
Ø 88,9 / 3,5 |
Ø 114,3 / 4,5 |
| triple type |
Ø 88,9 / 3,5 |
Ø 114,3 / 4,5 |
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