Geotechnical study in All

In the municipality of Tous, soils formed by limestones, dolomites and marbles predominate, implying rock subsoils with a high bearing capacity, which favours direct foundations on sound rock. However, in some areas fine sands and silts appear, albeit occasionally, offering lower strength and requiring careful assessments for foundation design. The presence of gypsum, anhydrite and salts, although in the minority, introduces the risk of underground dissolution, a factor to consider especially if water flows are detected at depth.

Seismic activity in Tous is notable, with 67 recorded events over the last 30 years, although the maximum magnitude (Mmax 3.4) does not require exceptional considerations in structural design. Given the presence of carbonate substrata, it is essential to check for cavities or karst processes before proceeding with any foundation, as these may affect ground stability. The non-clayey substratum allows expansivity problems to be ruled out, so the main geotechnical condition lies in characterising the karst and the possible dissolution of gypsum and salts.