Geotechnical study in Mesía

In the municipality of Mesía, the predominant geological substratum is formed mainly by sandstones, conglomerates and flysch, which together account for more than 85% of the ground. These lithologies generally exhibit a good bearing capacity, which favours the feasibility of shallow direct foundations in most cases. Although present in smaller proportions, slates and schists may induce a certain anisotropy in the ground’s response, whereas fine sands and silts are very rare and, due to their limited extent, have a limited impact within the overall context of foundation engineering in the area. The overall low permeability of these materials helps to avoid problems related to the migration of water at depth, although small, near-surface aquifers may exist that require specific attention.

Seismicity in Mesía is very low, with only 8 recorded events in the last 30 years and a maximum magnitude of 3.5, which minimises the need for specific measures for seismic design. The substratum does not contain layers of expansive clays, so the risk of expansivity is ruled out in this geotechnical context. No karstification features are identified, and therefore there are no constraints derived from cavities or instability due to dissolution. The main factor requiring attention for the geotechnical study in Mesía lies in the local heterogeneity of the formations and in the possible presence of near-surface groundwater levels associated with smaller aquifers.