Geotechnical study in Pradoluengo

In Pradoluengo, the most representative bedrock corresponds to phyllites and schists—metamorphic materials of low permeability—which predominate and provide good bearing capacity at most sites. Fine sands and silts occur occasionally, whereas limestones, dolomites and marbles appear in a very secondary way and, in minimum proportion, sandstones and conglomerates can also be observed. The overwhelming presence of metamorphic material favours conventional foundation solutions, although the low permeability may affect drainage during construction.

The seismicity recorded for the area is very low, with only 8 events over 30 years and a maximum magnitude of 1.8, and therefore it does not represent a relevant constraint for structural design. However, given that outcrops of limestones and dolomites exist, albeit infrequently, any local karstic phenomenon must be ruled out before proceeding with foundation works, since the presence of voids or underground dissolution would seriously affect stability. The non-clayey bedrock rules out any expansive risk, leaving the main factor to control as the possible presence of localised karstification in carbonaceous soils.