CFM Site Preparation from 2009 to 2010
While adequate sealing of the tunnel surface is essential for the success of the CFM experiment, it has been an extremely difficult requirement to fulfil. Since the beginning of the project in 2004, numerous considerations resulted in the implementation of three increasingly sophisticated sealing concepts. The final step in autumn 2009 was an improvement to the previously installed megapacker. While the 5 m long steel liner remained in place, the cement-filled Bullflex packers at each end were replaced with inflatable rubber packers. The improved megapacker sealing system has showed stable performance since then and appears to be suitable for the performance of the long-term in-situ experiment.
The groundwater monitoring and tracer testing instrumentation was augmented in November 2009 with two chemistry cabinets. These facilitate conservative, homologue and radioactive tracer testing. Their features include flow control and monitoring, online measurements of chemistry parameters, control of test parameters and sampling. For the in-situ experiment it may be necessary to modify the injection cabinet for long-term monitoring.
Excavation and removal of the cement packers.
Excavation of the cement-filled Bullflex packers on each end of the megapacker in September 2009
Donut packer installation in September 2009
Packaged and sent from the US to Grimsel
Arrival of the two inflatable rubber packers, also referred to as donut packers
With the rubber donut packers (seen as black ring) emplaced on either end, the steel megapacker (fondly referred to as “yellow submarine”) functions well; the blue chemistry cabinets are seen in the foreground
Two chemistry cabinets for injection and extraction during tracer tests, and adaptable for long-term monitoring
Completion of site preparation activities in November 2009
Colloid Formation and Migration Experiment