Extreme geotechnical investigations for TirrenoPower

CSI carried out three core drillings with the installation of monitoring instruments inside a confined tunnel at –13 m within the TirrenoPower dam. Complex logistics, very limited access, and guaranteed safety: a successfully completed operation that paves the way for the dam’s seismic retrofitting.

Between July and September 2025, CSI, on behalf of TirrenoPower S.p.A., completed a geological and structural investigation inside the dam in preparation for compliance with seismic regulations.

The activities included three boreholes between 15 and 18 meters deep, with the installation of piezometers and a fiberglass extensometer imported from the United States. All operations took place in a highly complex setting: a narrow pedestrian tunnel inside the dam, 13 meters below the surface, accessible only through a 70 x 70 cm hatch and just 60 cm wide.

Logistics were a true challenge. The Puntel MINIDRILL rig was lowered by helicopter and electric winch to the access shaft and manually transported along the tunnel. CSI ensured safe working conditions using ventilation systems, lighting, gas and oxygen detectors, as well as internal and external communication lines, including a satellite phone.

Thanks to careful planning, the experience of the drilling team, and continuous technical support, the intervention was successfully completed, providing TirrenoPower with the data and tools needed to safely carry out the seismic adaptation of the dam.