The purpose of works is ground freezing in order to excavate the crossing of the RER C in service, at the new Clichy Saint-Ouen station.
The tunnel to be built was 28 m long, 12 m wide and 11 m high and connected two existing shafts. In order to obtain the frozen cylinder, we then worked on two sides, installing a total of 61 freezing probes per shaft having an average length of 15 m, in order to obtain an overlap in the centre between the probes coming from the two sides. The linear total of probes is 1.800 m for freezing 1.200 m3 of soil at a temperature of -10° C. Approximately 1.200 m of ducts were laid for the nitrogen and brine distribution circuits.