Geotechnical study in Sant Joan Despí

In Sant Joan Despí, fine sands and silts predominate, accompanied in lesser proportion by gravels and compact sands. This soil composition implies bearing capacity values that are typically moderate, although the compaction of the gravels and sands can provide favourable conditions for shallow foundations, especially in lightweight or medium-scale projects. It is important to consider the presence of strata with low permeability, as shallow layers of groundwater may form that affect short-term stability in excavations.

The area shows very low seismicity, with scarce records and a low maximum magnitude, which limits its influence on structural design. The analysis indicates a non-clayey substrate, which eliminates the risk of expansivity in the foundations. Given the absence of karst and the nature of the soils, the main aspect to consider for the geotechnical study in Sant Joan Despí is grain-size variability, which directly affects the selection and sizing of the most suitable type of foundation.