Geotechnical study in Onda

In the municipality of Onda, sandy and silty soils predominate, together with a significant development of carbonate materials such as limestones, dolomites and marbles. This combination provides a base with generally favourable bearing capacity for foundations, especially over compact soils and rock. However, there is a localised presence of gypsum, anhydrite and salts, which entails a risk of dissolution and subsidence that must be assessed particularly in areas where these materials crop out. The predominantly non-clayey nature of the ground rules out risks associated with expansivity, providing greater stability for foundations compared with other areas of clayey substrate.

Seismic activity in the Onda area is very low, with only 7 recorded events over 30 years and a maximum magnitude of less than 2.1, meaning the seismic risk is practically negligible in structural design. On the other hand, the presence of carbonate materials requires a thorough check for evidence of karstification before carrying out any foundation work, due to possible cavities and collapses associated with these processes. The main geotechnical constraint in Onda lies in verifying karst-related phenomena and identifying zones affected by soluble soils; these aspects must be prioritised in the characterisation prior to the development of projects.