Geotechnical study in Puebla de Obando

In Puebla de Obando, phyllites and schists predominate, accounting for almost 90% of the geological substrate, whereas the presence of fine sands, silts, hard clays and some igneous rocks is only residual. These materials, with low permeability, usually provide a medium to good bearing capacity, allowing for shallow foundations in most cases. The uniformity and hardness of the substrate provides security for construction, although it is advisable to characterise in situ any potential presence of altered or fractured strata.

Seismicity in the municipality is considered notable, with more than 50 events recorded over the last 30 years, although the maximum magnitude (Mmax 4.4) does not fall much below the critical values. In the absence of karstic formations and given the non-clayey nature of the subsoil, the risk from expansivity is ruled out. The geotechnical aspect of greatest relevance in Puebla de Obando is linked to controlling the integrity and compaction of the phyllitic substrate, as well as considering seismicity in the analysis of the foundation system.