Just because something works in theory doesn’t mean that it will work in practice. Field trials and lab experiments serve the purpose of supplying practical proof. Or as the Romans say: Quod erat demonstrandum – what was to be shown.
Subsoil investigation – trenches, dynamic penetration, cone penetration tests
Permeability trials and pore water pressure measurements
Groundwater level measurements, monitoring of wells and springs
Soil mechanical experiments
Supervision of construction work
Plate load tests and installation density
Inclinometer and fissurometer measurements