Geotechnical study in Jerez de la Frontera

In Jerez de la Frontera, the subsoil is mainly made up of limestones, dolomites and marbles, accounting for around 40% of the surface, accompanied by fine sands, silts and, to a lesser extent, sandstones and conglomerates. These materials, typically solid and compact, provide good bearing-capacity conditions, facilitating the execution of shallow foundations when the groundwater level allows it. However, the occasional presence of soft expansive clays suggests the need for accurate characterisation to avoid localised areas of low strength and differential settlement.

The area has high seismicity, with 167 recorded events over 30 years, although the maximum magnitude observed (Mmax 4.4) does not reach the 4.5 threshold that would require additional considerations in the structural design. Given the dominant calcareous nature and the presence of karst, it is essential to check for cavities and dissolution in the subsoil before defining any foundation type, as the risk associated with hidden voids is the main geotechnical constraint in this municipality. The non-clayey substrate rules out the risk of expansivity over most of the area.