Geotechnical study in La Rioja

In the municipality of Rioja, the dominant substrate consists of phyllites and schists, followed by limestones, dolomites and marbles. Both lithologies provide a competent behaviour as a foundation support, although the presence of carbonate formations introduces the possibility of voids. Loose materials, such as fine sands and silts, as well as sandstones and conglomerates, appear infrequently and generally do not condition the choice of foundation type, which will normally be shallow in areas of sound rock and at depth if there are voids or fracturing.

The seismicity in Rioja can be considered high, with more than 150 recorded events over 30 years, although the maximum magnitude does not exceed 4. This level of seismic activity, despite its moderate intensity, must be taken into account in the geotechnical characterisation of the ground. On the other hand, the presence of karst associated with the limestone formations implies the obligation to analyse and verify the existence of caves or dissolutions beneath the foundation line. The non-clayey substrate rules out expansivity risks, so the main factor for a geotechnical study in Rioja is the possible influence of karst, which may affect the safety and stability of the project.