Geotechnical study in Miajadas

The municipality of Miajadas presents a variety of substrates, with the dominant presence of fine sands and silts, as well as outcrops of sandstones, conglomerates and flysch. This composition indicates that the soils usually show an intermediate bearing capacity, allowing the use of shallow or semi-deep foundations in most cases, always depending on the uniformity and local ground density. Granitic substrates and compact gravels are also found, which favour good stability for founding, whereas hard clays and slates are considered only occasionally and rarely condition the usual geotechnical works. The presence of water-bearing masses and silty-sandy areas requires particular attention to the groundwater level during the drafting and execution of the geotechnical study.

Seismicity in Miajadas is classified as notable, with 56 events recorded over the last 30 years, although with a relatively low maximum magnitude (Mmax 3.1). No karstification has been reported, nor are there any indications of risk due to expansivity, since the predominant substrate is not clayey, ruling out the issue of expansive soils in the area. The most relevant factor to consider in geotechnical studies for projects in Miajadas is lithological variability, particularly in areas where materials of different stiffness and permeability alternate, which requires detailed characterisation to ensure the safety and performance of the designed foundations.