Ground investigation: a tool for landslide risk mitigation of infrastructures

Recent monitoring experiences for bridges in Central and South Italy have shown that it is not common for bridges to be directly damaged by landslides phenomena in their vicinities, either because their siting was very carefully selected at the origin or because appropriate protection measures have been taken to reduce geological risk to acceptable levels. In the first case, periodic visual inspections of the manufacts may suffice to monitor possible consequences of ground instability phenomena, but in the second case monitoring of the infrastructure and of the ground is the only possible tool to evaluate the existence of a landslide-structure interaction which can influence its performance and safety. Ground investigation is a fundamental activity for landslide monitoring and analysis, and this is specifically true when a landslide-infrastructure interaction problem needs to be investigated and assessed. By discussing the results from case studies recently inspected, this paper shows how the knowledge of the physical processes and the monitoring of selected parameters are the first irreplaceable tools to mitigate risks associated with instability phenomena interacting with sensitive infrastructures.