Geotechnical study in Cumbres Mayores

In Cumbres Mayores, the predominant substrate is made up of slates and schists, metamorphic materials that occupy most of the municipality. These lithologies, combined with a low presence of granite, gneiss and igneous rocks, generally provide good bearing capacity for shallow (direct) foundations, although their marked impermeability may favour the accumulation of water at the surface or in local aquifers. It is essential to avoid founding on the occasional levels of deltaic muds and peats, as they have an extremely high compressibility and low strength, which could compromise structural stability.

With regard to the relevant geotechnical risks, the area has very low seismicity, with barely three events over thirty years and a maximum recorded magnitude of 3.1, which rules out the need for special seismic measures in design. The non-clayey substrate eliminates the risk of soil expansivity. In conclusion, the main constraint in the geotechnical studies for Cumbres Mayores lies in identifying and excluding peat and mud levels for the foundation, making use of the stable metamorphic formations as a safe base.