**6. Conclusions**

Some aspects that are not directly investigated characterize the situations examined. The first one concerns the materials constituting a wall system built in the fifteenth and sixteenth centuries, completely integrated into the city center; this wall system is bordered by an area in which an underground car parking is planned and the excavation could create dangerous conditions for the wall system itself. In the second case, problems arise from the effects of groundwater in the alluvial soil covering a hill, on the flank of which runs a road. Here, in the case of intense meteoric conditions, the groundwater reaches the foot of the slope and determines its instability, by rotational kinematics, in an unexpected way.

In both cases, traditional geotechnical investigations do not solve the problems. Conversely, geophysical surveys integrate the knowledge framework and provide the fundamental elements for the development of back or sensitivity analysis, which can be performed with numerical methods, based on reliable geomechanical models.

Based on the results obtained, it was possible to conclude that:

