Gas-Permeable Seal Test - Water Injection Phase
The sand/bentonite seal has been saturated through the sand filter on the side of the concrete plug:
- Phase I - Saturation of the injection filter (11th – 17th July 2012)
- Phase II - Pressurization Phase: The pressure was increased in steps until a manometric height of around 3.5 m was reached (17th July 2012 – 29th April 2013)
The pressure was increased in steps until a manometric height of around 3.5 m was reached
- Phase III - Saturation Phase (29th April 2013 – 29th January 2014). A rate injection is performed
- Leak event (28th January 2014)
- Depressurisation and remediation (29th January 2014 – June 2015)
- Phase VI – Remediation and Resaturation (July 2015)
Longitudinal cross section of the GAST experiment with instrumentation sections Sxx and levels Lx (not all sections and levels shown). Superposed is a vertical section of interpolated pore pressures as observed on 31.12.2013.
a) Injection phases and water flow, b) head space relative humidity, c) S/B pore pressure, d) total pressure at tunnel surface. Sensor code in legends: [Sensor type]_[Section]_[Level] (see figure above for positions).
Gas-Permeable Seal Test (GAST)