Geotechnical study in Torroella de Montgrí

In Torroella de Montgrí, fine sands and silts predominate, together with formations of calcareous origin such as limestones, dolomites and marbles. This geotechnical context indicates a variable response in bearing capacity: while the limestone formations offer good support conditions for shallow or deep foundations, the presence of zones with muds and peats of deltaic origin represents a risk to stability, so it is essential to avoid founding on these compressible and low-competence materials. The sandy and silt-sandy horizons, with low permeability, may require specific studies to control the presence of shallow aquifers and to ensure the durability of the structure.

Seismic activity in the area is very low, with only two low-magnitude events recorded over three decades, which limits the impact of this factor on structural design. Given the abundance of limestones, dolomites and marbles, there is the possibility of karstification developing, which requires detailed verification before proceeding with any foundation type due to the potential presence of cavities. The absence of expansive clays rules out the risk of swelling in foundation soils. The main technical constraint here is the need to investigate the presence of karst and ensure that foundations are supported on competent layers, avoiding the sectors with muds and peats.