The Follo Line project is currently the largest infrastructure project in Norway. On this job, Keller installed around 1000pc of Jet grouting columns to support the excavation of a portal linking two major parts of the project.
The project
The project includes 22km of new railway from Oslo to Ski. The main part of the works was the construction of a Portal from the transition zone from Drill and Blast to the Cut and Cover tunnelling into Oslo S.
The challenge
Multiple stages of execution with parallel activities, Jet grouting, injections and anchors. Lack of space due to rural surrounding area with active roads and railway traffic was also an issue.
The solution
With its large foundation portfolio, Keller has been able to assist the client with several different technologies when adjustments have become necessary. This eliminated eventual time loss for the client. Due to the difficult soil conditions many different types of machinery and drilling techniques were used to ensure the stabilisation of the overburden soil and quick clay before reaching the excavation level of 12m height. Keller applied reinforced Jet grouted columns with strand anchors between them, Shotcrete, Fibreglass anchors and Rock bolts.