Geotechnical study in Leganés

In Leganés, the predominant ground consists of sandstones, conglomerates and flysch, which represent the most common base for foundations in the area. These materials usually exhibit good bearing capacity and provide favourable conditions for shallow foundations, particularly in areas where compact gravels and sands occur. However, although limestones and dolomites are very infrequent, the local presence of these materials can modify the ground response at specific points. The existence of extensive aquifers with moderate permeability must be taken into account in the foundation design, mainly due to the possible influence on the groundwater table during construction.

As regards seismic dynamics, Leganés shows very low seismicity, with only one event every thirty years and a maximum magnitude of less than 4, so this factor does not significantly condition the structural design. There is no risk of karstification in the municipality due to the scarce presence of carbonate materials. Nevertheless, it is important to highlight the risk associated with the presence of dispersed non-expansive clays within the matrix; although the expansivity risk is tempered, it is advisable to analyse these zones in detail and avoid founding on layers that could prove problematic. In short, the key factor to control is the possible presence of interbedded clayey strata that could affect the stability of the foundations.