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Jet injection is a measure that is carried out so that the tunnel can be blasted out safely and in order to protect the groundwater levels.
What is jet injection?
Jet injection involves drilling holes through the ground down to the base of the rock and filling the holes with cement under high pressure. The measure is carried out in order to ensure that the tunnel driving can take place safely and to protect the groundwater levels. The figure below shows how earth and ground reinforcement takes place with jet injection.
What is the procedure?
Step 1. First, holes are drilled down to the level where the jet injection will begin, usually down to the base of the rock.
Step 2. A cement suspension is pumped through a nozzle using high energy while the drill string simultaneously rotates slowly and is pulled upwards.
Step 3. When the jet pillars have hardened, the earth and the ground are reinforced.
How much noise is there?
An important element of environmental work is to limit noise levels. The heavy vehicles and work equipment used in the jet injection can be disturbing.
We work constantly to cause as little disturbance as possible by taking various measures and using adapted work methods. We apologise for any disturbance caused by the work. There are guideline values that govern how much noise we can make. For this reason, we will conduct control measurements.