Abstrakt
Electrical resistivity tomography (ERT) as a tool for monitoring the processes and time-related changes in geological environments has made great progress in recent years and has become standard for observing natural phenomena. This method is simple to use and it often provides high-quality results that are well interpreted.
Our research is based on observing time-lapse changes of the physical parameters (conductivity, for instance) of joints systems (mostly in crystalline massifs). The primary aim is to develop a monitoring system mostly for the needs of deep repositories of nuclear waste.
Geophysical research of such repositories has so far dealt only with one-off research (no time-monitoring) of potential host rocks properties. Contrary to this, our developed system and methodology is unique in continuously measuring the physical properties (in this case, electrical resistivity) of the rock massif.
This system will be permanently fixed in the field and by observing changes in measured data reports if any remarkable occurrence in the EDZ zone is or was happening (for example, opening or closing of the joints or microfractures). Today, our monitoring system is being developed and tested at the field base in Bedrichov (northern Bohemia).
The Bedrichov gallery is approximately 2.5 km long and continuously leads through one type of granite massif. Point 792, where a significant geological fracture zone goes through, was chosen as an ideal place for taking repeated measurements via our ERT system.
Currently, we test the measurement quality, such as whether our system provides real data and is able to reliably observe resistivity changes measured at ERT profiles.