ABSTRACT
Weathering of soft rocks is well known phenomenon that causes many problems in geotechnical constructions. Marl from Eocene flysch strata found in Dalmatia region in Croatia, is just one example of these soft rocks. Excavations in these strata such as those for construction pits or cuttings for roads, have considerable problems with durability. Durability problem is caused with marl strength degradation induced by the weathering. Excavation in these materials can be performed only with use of heavy machinery (rock breaker) or explosives, as well as in any other rock. However, in relatively short time after excavation, about few months, in which period excavated slope in marl is exposed to influence of atmospheric agents, weathering process starts on the slope surface. Repeated cycles of wetting and drying, heating and cooling, freezing and thawing, as parts of weathering process can cause marl to deteriorate into soil like materials. For an example, as a consequence of weathering, a cut that was stable after excavation even with almost vertical inclination, could become instable in the engineering time scale (i.e. a period ranging from a few years to a few decades, in which construction is in use).
