Geotechnical study in Santa Coloma de Gramenet

In Santa Coloma de Gramenet, soils formed by granite, gneiss and other igneous rocks predominate, which confers a high bearing capacity and offers favourable conditions for direct foundations on sound rock. Fine sand and silt environments are also present, which require a detailed assessment of the compactness and fines content to avoid differential settlement, whereas the occasional presence of overconsolidated clays and marls, compact gravels and slates may locally influence the most recommendable foundation type. Given the low permeability of most formations, there is usually little water circulation, except in isolated shallow aquifers.

Seismicity in this municipality is very low, with only 5 events recorded over 30 years and a low maximum magnitude (Mmax 1.6), so it does not represent a relevant constraint for structural design. There is also no risk of karst formation or problems of expansiveness, as the subsoil is not clayey. In conclusion, the main geotechnical consideration to be assessed in Santa Coloma de Gramenet focuses on the presence of granitic materials and their state of alteration or weathering as a key factor in defining the foundation system.