Geotechnical study in Tordera

In Tordera, granitic soils predominate, along with gneisses and other igneous rocks, which constitute approximately 75% of the subsoil. This type of material is characterised by a high bearing capacity and favourable stability for solutions involving direct foundations. The fine sands and silts present occasionally may show a local reduction in bearing capacity, whereas the limestones and dolomites, due to their low frequency, have a lesser impact at a general level. The formations are generally impermeable or of very low permeability, which limits the risk of issues associated with the groundwater level except in specific areas with shallow aquifers.

The seismic activity in Tordera is considered moderate, with 20 recorded events over the last 30 years and a maximum magnitude of 2.6, far below the thresholds that would affect conventional structural design. The risk of expansiveness is ruled out, since the subsoil is not clayey. Nor are there any signs of karstification identified. Therefore, the main factor to take into account in geotechnical studies will be the accurate characterisation of these hard materials and the possible identification of areas with loose granular material, which may require special treatment in the foundation.