Gas Migration in EBS and Geosphere (GMT) - Excavation of the EBS - Overview
The aims of the excavation and characterisation phase of the Gas Migration Test (GMT) were:
- Evaluation of EBS following the gas test;
- Determination of sand/bentonite properties
- Detection of gas- and water-flow paths;
- Assessment of the construction methods used;
- Evaluation of interface properties (concrete silo/buffer concrete joint, instrumentation arms, risers);
- Assessment of concrete silo performance and interaction of concrete and bentonite/sand effects
- Recalibration of instrument
The excavation and characterisation of the silo was carried out in a series of eight steps (explained in greater detail in the sections shown in the side menu above):
Step 1: Depressurisation of GMT Cavern.
Step 2: Cutting through the concrete plug.
Step 3: Removal of backfill from GMT Cavern.
Step 4: Investigations from top of Layer 12.
Step 5: Removal of sand/bentonite by layers to top of concrete silo.
Step 6: Investigations in Layers 8 and 7.
Step 7: Removal of Layers 6-5.
Step 8: Restoration of GMT site.