Redpath-Deilmann and DMI Injektionstechnik signed contract for ground freezing work in the Netherlands as a joint venture "Freezing Comol 5"
At the beginning of April 2020, Redpath-Deilmann, together with DMI Injektionstechnik from Berlin, signed the contract for ground freezing work on a tunnel construction site in the Netherlands as JV "Freezing Comol 5".
A large highway and tunnel project has been underway under and around the cities of Leiden and Voorschoten, which lies between Den Haag and Amsterdam in the province of South Holland. The tunnel, the main component of the so-called "Rijnlandroute", is being built by the JV Comol 5. Comol5 is an international association of Mobilis BV, Croonwolter & dros BV, VINCI Construction Grands Projets SAS and DEME Infra Marine Contractors BV.
The Rijnland Route consists of a two-tube motorway tunnel with a finished diameter of 9.7 m and a length of 2.25 km. The tunnel will connect the dutch A4 to the A44 and is intended to reduce through traffic through the city of Leiden. For this purpose, two large motorway junctions are also being built.
The two tunnel tubes are constructed by using a Hydroschild tunnel boring machine built by “Herrenknecht”. The first tube broke through at the end of January 2020. The tunnel boring machine is currently being reassembled at the starting point of the second tunnel after being transported back from the target shaft of the first tunnel.
The start of the work of the joint venture “Freezing Comol 5” is scheduled for the end May. Then the start of drilling for the freeze and temperature measuring holes as well as the first installations for the freeze pipes are planned. These are required to create eight cross passages (connections between the tunnel tubes for maintenance work and as escape routes) in the sandy and water-bearing soil.
The drilling work for this is carried out by DMI Injektionstechnik GmbH. Redpath-Deilmann has already been successful with DMI, e.g. worked together on our ground freezing construction site in Hamburg for the Hamburger Hochbahn.
In contrast to tunnel construction projects, where Redpath-Deilmann was already involved in ground freezing measures in the past, this project has a completely different workflow:
The necessary freeze pipes, which are necessary for the freezing of the ground, are drilled and prepared in two stages with a construction interruption of 5 weeks. In addition, in this project, some of the pipes are already being drilled from the first tunnel, although the second tunnel, which is normally used as a reference or end point for the hole length, is drilled before the tunnel boring machine passes through. The holes for freezing are therefore partially shorter than usual.
Two large drilling rigs are used during the work, some in parallel operation, as well as eight freezing machines with up to 100 kW cooling capacity and small freezers (10kW) for additional surface cooling.
The further course is reported.