Geotechnical study in Pallejà

In Pallejà, the subsoil is characterised by a marked presence of gypsum, anhydrite and salts, as well as limestones and dolomites in significant proportions. These materials give the ground a high permeability, favouring the presence of extensive and productive aquifers, which must be taken into account in the design of foundations to avoid problems associated with groundwater and possible dissolution of soluble materials. Mixtures with sandstones, conglomerates and hard formations of slates or schists indicate variable bearing capacity, where precise identification of the load-bearing layers is essential in order to define the optimal foundation type.

Seismic activity in Pallejà is very low, with only two recorded events in thirty years and a maximum magnitude Mmax of 1.6, so it does not represent a relevant constraint in structural sizing. However, the existence of karst processes is a determining factor, especially in the presence of gypsum and soluble materials, making a specific geotechnical assessment of the karst essential before undertaking any foundation project. On the other hand, since it is a non-clayey substrate, the risk of expansiveness is ruled out, leaving as the main constraint the need to control dissolution phenomena and cavities associated with the karstic ground.