ABSTRACT
The monitoring plan is an essential part of a project. The main goals of monitoring activities during construction are to detect warning signs of instability in a timely fashion and to optimize the design. This chapter focuses on the geotechnical and structural monitoring of tunnels, operating a distinction based on where the measurements are taken from inside the tunnel or on the ground surface. Following the identification of the most relevant physical quantities, the more suitable instruments and measurement techniques are briefly described. Finally, some considerations are made regarding the peculiarities of the calculations that should be carried out to obtain predictions truly comparable with monitoring data and the possibility to use this comparison to improve the predictive models through back-analysis while the excavation is still ongoing.
