Geotechnical study in Lerín

In the municipality of Lerín, soils of gypsum, anhydrite and salts predominate, making up more than a quarter of the substrate, accompanied by fine sands, silts, limestones, dolomites and compact materials such as gravels and sands. This lithology confers a variable bearing capacity, with areas containing gypsum and salts presenting a risk of dissolution that may affect ground stability, whereas sandy and calcareous strata can provide good conditions for foundation, provided their compaction is adequate. The presence of highly productive, permeable aquifers increases the importance of a detailed analysis of the water table and the possible interaction between groundwater and soluble materials.

Seismic activity in Lerín is very low, with only around 5 events over 30 years and a maximum magnitude of 2.6, so seismicity does not constitute a significant constraint for structural design. However, given the presence of soluble materials and the influence of karst, it is essential to check for cavities or underground dissolutions before carrying out any foundation, as this factor is the main geotechnical constraint in the municipality. As we are situated on a non-clayey substrate, the risk of volumetric ground expansiveness is ruled out, and the analysis focuses on the stability and homogeneity of the subsurface related to dissolution phenomena.