Table 1 Features of the main in situ heating tests performed in the Mont Terri rock laboratory
Experiment | HE-B (HE) | HE-D | HE-E |
|---|---|---|---|
Borehole/tunnel | Vertical | Horizontal | Horizontal |
Borehole/tunnel diameter (m) | 0.3 | 0.3 | 1.3 |
Heater/liner diameter (m) | 0.1 | 0.3 | 0.3 |
Heater length (m) | 2.02 | 2 × 2 | 2 × 4 |
Max. heater temperature (°C) | 100 | 100 | 140 |
Backfill thickness (m) | 0.1 | – | 0.5 |
Backfill material | Compacted blocks (Febex bentonite) | – | Granular bentonite (MX80, MX80 + sand) |
Backfill hydration | Artificial | – | Natural |
Heating duration | 18 months | 11 months | Long term |
Heating period | February 2002–August 2003 | March 2004–February 2005 | June 2011–? |