TUNNEL VAL DI SAMBRO
Monitoring of the highway tunnel, Val di Sambro. A1 Milan – Naples.
Adjustment of the Apennine stretch between Sasso Marconi and Barberino di Mugello
Customer: SPEA Engineering - Atlantia Group
The "OF” System has been designed and installed in Val di Sambro tunnel, with the aim of controlling its convergence and longitudinal deformations, as the tunnel is located in a land landslides-prone. The "OF" System monitors longitudinal deformation due to thrusts generated by the land surrounding, as well as convergence measurements in key points of the tunnel.
3 lines of sensors have been installed along the whole tunnel, while the thermal sensors have been installed at distances previously set. This to compensate the effects, on the readings, of thermal variations and to obtain a pure mechanical deformation. It is possible to control the longitudinal movements of the tunnel, and verify if the tunnel "keeps" the initial shape as designed.
For additional monitoring, in the two critical points of the tunnel, about 20 sensors have been installed to control the convergence, i.e. to verify that the tunnel maintains its curvature radius.
In case of anomalies, i.e. when sensor reads a deformation greater than the preset threshold, the system sends an alarm by email to worn that a sensor, at that particular point, is registering tension over the safety threshold; so that it is possible to intervene quickly and precisely in the affected area.
The sensors used are strain and temperature sensors, connected to a single acquisition machine running the "OF" Software that provides, in real time, analysis of parameters to be monitored.
Sensors carried out the measures simultaneously, with a frequency of ten data per second. 780 were the sensors installed. About 30 were the kilometres of optical fiber installed. Data per second, acquired by the operating system, were more than seven thousand. The system is operational 24/24h, 365d/year.
30 km of optical fiber
7.800 data acquired per second
4 PLE (working platform, lifting)
System installation time: 18 days
20 technicians/engineers involved in the system assembling
NTSG supports the customer in data analysis and maintenance of the system, providing the costumer web interface for the visualization and control of the readings taken by the system and the alarms recorded.