Geotechnical study in Santovenia de Pisuerga

In Santovenia de Pisuerga, the dominant ground consists of limestones, dolomites and marbles: hard, stable materials that provide excellent bearing capacity for shallow or deep foundations. Compact gravel and sand, also common, provide conditions of high permeability and drainage, facilitating the discharge of water and reducing the risk of problems due to capillary rise. However, the significant presence of gypsum, anhydrite and salts implies a potential risk of dissolution, especially in contact with extensive aquifers, which can lead to subsidence or cavities beneath foundations. The bodies of water and the rarity of fine sands and silts are secondary aspects, but they should be considered locally, particularly with regard to groundwater levels and possible seepage.

With regard to seismicity, the municipality records high activity, with 200 events over 30 years and a maximum magnitude of 4.7, so it is essential to incorporate the seismic factor into structural design. Given the karstic nature of the ground, it becomes a priority to check for voids or dissolution processes before any foundation project, alongside the risk associated with gypsum and salts. Expansive clays only appear in a subordinate way, so the risk due to expansivity is secondary. Thus, the combination of karstic risk, soluble soils and seismic activity constitutes the main geotechnical constraint in Santovenia de Pisuerga, making it mandatory to carry out a detailed geotechnical study prior to any works.