Geotechnical study in Xunqueira de Ambía

In Xunqueira de Ambía, the predominant substrate consists of sandstones, conglomerates and flysch, representing most of the materials in the municipality. In general, these ground conditions provide good bearing capacity conditions for shallow foundations, although it will be necessary to analyse any occasional levels of clays and hard marls which, although overconsolidated, may have variable behaviour depending on their moisture condition or fracturing. It is important to take particular care regarding the local presence of muds and peats of deltaic origin, which are not suitable for supporting foundations due to their low strength and high compressibility, and should therefore be avoided as a structural bearing stratum.

Seismicity in this area is moderate, with 18 recorded events in the last 30 years and a maximum magnitude of 3.1, which indicates that seismic risk is low from a structural point of view and does not significantly condition the design. There are no signs of karstification or problems associated with gypsum, salts or anhydrites. In addition, the absence of a clayey substratum excludes the risk of expansivity, simplifying the predictability of geotechnical behaviour. Therefore, the main local geotechnical constraint lies in identifying and avoiding foundation settlement on muds or peats, prioritising outcrops of hard, competent materials.