Geotechnical study in San Lorenzo de la Parrilla

In San Lorenzo de la Parrilla, the dominant substrate is mainly composed of formations of limestones, dolomites and marbles, which provides solid and stable soils ideal for building and good performance in terms of bearing capacity for most foundation projects. However, the occasional presence of gypsum, anhydrite and salts introduces a potential risk of dissolution in the subsoil, which can lead to stability problems if an adequate geotechnical characterisation is not carried out. It is also important to highlight the existence, although limited, of expansive white or soft clays which should be particularly considered in the areas where they crop out, as they can locally influence the choice of foundation type.

Seismicity in the area is very low, with only one recorded event in thirty years and a low maximum magnitude, so this factor does not represent a relevant technical constraint for structural design. The risk of expansivity, although present in subordinate cases, is mitigated by the dominant nature of the substrate and by climatic conditions that do not favour the activation of expansive clays. No karst development is detected in the area. In conclusion, the main aspect to be studied in the geotechnical campaign will be the possible effects of gypsum and salts in the substrate, which could compromise the stability of foundations if their behaviour and extent are not analysed appropriately.