Geotechnical study in Onzonilla

In Onzonilla, soils formed by fine sands and silts predominate, with a significant presence of sandstones, conglomerates, flysch, as well as compact gravels and sands. These materials generally show good bearing capacity, facilitating flexible construction options for shallow foundations. However, it is essential to analyse the heterogeneity of the materials, as silts may exhibit variable behaviour under loads and moisture changes, and areas with masses of water suggest zones of high permeability that require particular attention in drainage management.

Seismicity in Onzonilla is characterised by high activity, with 200 events over 30 years and a maximum magnitude of 4.7, which necessitates incorporating seismic criteria into the structural and foundation design calculations. Although expansive clays are present, their occurrence is subordinate or found in climate areas without deficit, so the risk from expansivity is low, with seismic action being the main constraint to take into account during the planning and execution of the geotechnical study.