A contribution to the better understanding of swelling in soils and soft rocks

Abstract

Swelling and shrinkage of sediments rich with clay belong to geologically conditioned risk factors. Economic loss as the consequence of volume changes in the geological catchment area of buildings and infrastructural objects is immense. Untimely detected swelling causes higher prices and unnecessary delays during the construction. In those cases when deep cuts and underground spaces are used as intervention into highly preconsolidated soils and soft rock with clay contents, failures of embankments and improperly designed supporting measures due to swelling are not infrequent. Also periodic appearance of landslides at certain areas can be the consequence of swelling. Some countries, such as the USA, introduced the guidelines and standards for the detection, assessment and handling with swellable geological materials decades ago. Due to some other more urgent geologically conditioned risks, such as landslides, earthquakes and constructions on soft ground, in Slovenia the development of knowledge in the area of swelling soils was several years behind the knowledge in the rest of the world. With the construction of the Slovenian-Hungarian railway connection after 1998, motorways and the introduction of new knowledge about soil suction, also Slovenian experts were introduced to a different dimension of the problem of swelling soils, as well as some important experiences were learned and new possibilities for the investigation and understanding of volume behaviour of swelling soils were opened. This is especially important for the predicted weather extremes, as only adequate knowledge will allow us to adequately explain any new phenomena in the ground and prepare appropriate protection.