For projects of some importance, or where the realization may be critical, monitoring is an important part of the geotechnical investigation program. Observations and measurements are essential elements in these investigations, and form the final part of the geotechnical investigation.
A geotechnical design is, after all, to a certain extent hypothetical. The geotechnical investigation, as extensive as it may be, gives input to a geotechnical model which can by no means cover all facets of soil behaviour. The designer must therefore make certain (simplified) assumptions, based on a long time experience and available geotechnical data.
Observations and measurements on site are very valuable for the geotechnical engineer to overcome the uncertainties of geotechnical design and to achieve sustainable and economical designs.
Although monitoring is primarily associated with measurements during the execution phase of projects, it can also be a useful tool to optimize design. Also after realization of a project, we continue monitoring to better understand soil behaviour and calibrate our design parameters.