Tunnel restoration in unstable rock masses: Numerical analysis and validation of monitoring data from innovative instrumentation

The increase of global temperatures caused shortages of water supply in several Italian cities. One of the challenges of responsible institution is how to maintain and restore the old aqueducts facilities. In particular, the most critical problem is related to the water losses along the aqueduct pipes and tunnels due to the aging of the structures and the damages caused by rock mass instabilities. This paper deals with one of these cases, where an aqueduct tunnel, damaged by the progressive movement of a rockslide, underwent to a complete reconstruction. The restoration design required the installation of CIR-Array, an innovative automated monitoring system, which would enable to monitor the surrounding rock mass, as well as the provisional reinforcement and the final lining, during both construction and operational phases. This case has been the first in situ application of this instrumentation and it represents an interesting test, complementary to the previous laboratory one. Construction works are still in progress, as well as the installation of monitoring instrumentations. In this paper, the preliminary results are presented, described and then compared with the expected behavior of the rock mass predicted by the design numerical model.