Continuous coring perforations represent the only “direct” method of investigation in the context of the diagnosis of non-invasive techniques, because the withdrawn soil sample has an infinitesimal size compared to the extension of the survey area. As far as possible, soils coring must be a dry coring performed with a 10 cm diameter corer. To avoid overheating phenomena of the cored material is therefore preferable to the use hydraulic hammers that allow a dry coring percussion minimizing the overheating of the cored soil. After the coring manoeuver, the hole must be provisionally coated. If the use of circulation fluids is necessary, clean water, possibly added with biodegradable polymers, is recommended. It is strictly forbidden to use water and / or the recovery fluid. United to geophysical prospecting, core drilling is a useful tool to quickly ascertain the nature of some anomalies. To assess the extent of any cavity or interspaces, detected by other methods, it is possible, under certain conditions, to enter into the hole fibre optic detection tools. The soil samples, extracted in predetermined points, allows a direct reading of the stratigraphic situation with the following purposes:
- Geomorphological reconstruction of the landscape;
- Determination of the depositional environment and the conditions of the deposits formation;
- Assessing of anthropogenic layers presence;
- Analysis of flora and fauna macroremains and palynological analysis.