Geotechnical study in La Zubia

In La Zubia, the subsoil is composed mainly of limestones, dolomites and marbles, accompanied by significant proportions of fine sands, silts and gypsum, as well as occasional occurrences of clays and hard marls. These stone materials, being dominant, allow for shallow or semi-deep foundations in most cases, provided that a support level is achieved away from the bands containing gypsum, anhydrite or salts, since there is a risk of dissolution in the latter. The sands and silts, although common, require the study of their density and possible compressibility, whereas overconsolidated clays, being hard and not very extensive, determine the footing type to adopt.

The area has a moderate seismic context, with 47 recorded events over 30 years and a maximum magnitude value of 5.8, which implies that seismic effects must be considered in detail in the geotechnical and structural design. The possible presence of karstic cavities associated with limestones and dolomites requires an exhaustive verification of the karst before implementing any foundation system. In addition, the existence of gypsum and salts highlights the importance of allowing for dissolution processes. The central geotechnical constraint for La Zubia lies in the proper management of karstic and seismic risks, together with special attention to gypsum-bearing zones.