Stone cold blasting at Gullmarsplan
At Gullmarsplan, part of the rock had to be frozen in order to finish building the track tunnel. Now that the rock has reached the right temperature, the blasts are in full swing.
During the spring and summer, freezing has taken place by pumping coolant into approximately 40 meter long pipes in the tunnel under Mårtensdal. The area consists of soft rock, and in order to be able to blast more safely, the rock is therefore frozen to at least -5 °C.
– We have reached about a third of the distance in one tunnel tube and have just started the other, says construction manager Mathias Tisjö Brinck.
This video shows the tunnel and the frozen mountain. Notice ice crystals on the tunnel walls:
It has been a bit of a slow start to this section as we had problems getting the shotcrete to stick to the frozen surface. Now, however, we have found a method that seems to work and hope that the rest will go on without problems.