Geotechnical study in Sant Just Desvern

In Sant Just Desvern, the predominant geotechnical substrate is formed mainly by highly hard overconsolidated clays and marls, accompanied in smaller proportions by occasional slates and schists, as well as by occasional fractions of compact gravels and sands. This composition provides good bearing capacity for buildings, especially over the marls and hard soils, while the presence of granular materials, although less frequent, can optimise drainage in certain sectors. The dominant formations, in general, exhibit low permeability, which limits infiltration and may enhance the surface bearing capacity, but requires verifying the existence of shallow aquifers that could influence the long-term behaviour of foundations.

Seismic activity in Sant Just Desvern is very low, with only about 5 events over 30 years and a maximum recorded magnitude of 1.6, which implies an almost negligible seismic hazard for standard structural design. There is no evidence of karst-related risk in this area, and the absence of a clayey substrate eliminates concerns regarding expansivity. As a result, the main geotechnical constraint in Sant Just Desvern lies in the appropriate characterisation of the continuity and compactness of the local hard materials, promoting a stable and reliable shallow foundation for most construction interventions.