Geotechnical study in Amposta

In Amposta, calcareous rocks, dolomites and marbles predominate as substrates, accompanied by fine sands and silts in significant proportions. These materials generally offer good bearing capacity for buildings, although the occasional presence of sands and silts may slightly affect this capacity, particularly if the levels of fines are high. Hard deposits of clays and marls are also observed, although they have a limited distribution. Owing to the composition and characteristics of the substrate, it is usual for foundation projects to be approached with direct solutions, adjusting the design to the thicknesses and actual quality of each identified material in the boreholes.

The level of seismicity in the municipality is moderate, with 18 events in the last 30 years and a low maximum magnitude (Mmax 2), which does not impose additional structural requirements linked to significant seismic action. However, special attention should be paid to karstification processes in the limestones and dolomites, as these may cause cavities or ground instability; this aspect requires prior verification before any foundation approach is considered. The fact that the substrate is not clayey eliminates the risk of expansiveness, so the main geotechnical limiting factor in Amposta will be the detailed assessment of the karst associated with the carbonate formations.